显示样式:     当前分类: 医药    当前期刊: Molecular Cancer Therapeutics    加入关注    导出
我的关注
我的收藏
您暂时未登录!
登录
  • Inhibition of the Receptor Tyrosine Kinase AXL Restores Paclitaxel Chemosensitivity in Uterine Serous Cancer
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-01-01
    Marguerite L. Palisoul, Jeanne M. Quinn, Emily Schepers, Ian S. Hagemann, Lei Guo, Kelsey Reger, Andrea R. Hagemann, Carolyn K. McCourt, Premal H. Thaker, Matthew A. Powell, David G. Mutch, Katherine C. Fuh

    Uterine serous cancer (USC) is aggressive, and the majority of recurrent cases are chemoresistant. Because the receptor tyrosine kinase AXL promotes invasion and metastasis of USC and is implicated in chemoresistance in other cancers, we assessed the role of AXL in paclitaxel resistance in USC, determined the mechanism of action, and sought to restore chemosensitivity by inhibiting AXL in vitro and in vivo. We used small hairpin RNAs and BGB324 to knock down and inhibit AXL. We assessed sensitivity of USC cell lines to paclitaxel and measured paclitaxel intracellular accumulation in vitro in the presence or absence of AXL. We also examined the role of the epithelial-mesenchymal transition in AXL-mediated paclitaxel resistance. Finally, we treated USC xenografts with paclitaxel, BGB324, or paclitaxel plus BGB324 and monitored tumor burden. AXL expression was higher in chemoresistant USC patient tumors and cell lines than in chemosensitive tumors and cell lines. Knockdown or inhibition of AXL increased sensitivity of USC cell lines to paclitaxel in vitro and increased cellular accumulation of paclitaxel. AXL promoted chemoresistance even in cells that underwent the epithelial-mesenchymal transition in vitro. Finally, in vivo studies of combination treatment with BGB324 and paclitaxel showed a greater than 51% decrease in tumor volume after 2 weeks of treatment when compared to no treatment or single agent treatments (P<0.001). Our results show that AXL expression mediates chemoresistance independent of EMT and prevents accumulation of paclitaxel. This study supports the continued investigation of AXL as a clinical target, particularly in chemoresistant USC.

    更新日期:2017-09-14
  • Superior properties of Fc-comprising scTRAIL fusion proteins
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-01-01
    Meike Hutt, Lisa Marquardt, Oliver Seifert, Martin Siegemund, Ines Müller, Dagmar Kulms, Klaus Pfizenmaier, Roland E. Kontermann

    The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been considered as a promising molecule for cancer treatment. However, clinical studies with soluble TRAIL failed to show therapeutic activity, which resulted in subsequent development of more potent TRAIL-based therapeutics. In the present study, we applied defined oligomerization and tumor targeting as strategies to further improve the activity of a single-chain version of TRAIL (scTRAIL). We compared three different formats of epidermal growth factor receptor (EGFR)-targeting dimeric scTRAIL fusion proteins (Diabody (Db)-scTRAIL, scFv-IgE heavy chain domain 2 (EHD2)-scTRAIL, scFv-Fc-scTRAIL) as well as two non-targeted dimeric scTRAIL molecules (EHD2-scTRAIL, Fc-scTRAIL) to reveal the influence of targeting and protein format on anti-tumor activity. All EGFR-targeted dimeric scTRAIL molecules showed similar binding properties and comparable cell death induction in vitro, exceeding the activity of the respective non-targeted dimeric format and monomeric scTRAIL. Superior properties were observed for the Fc fusion proteins with respect to production and in vivo half-life. In vivo studies using a Colo205 xenograft model revealed potent anti-tumor activity of all EGFR-targeting formats and Fc-scTRAIL and furthermore highlighted the higher efficacy of fusion proteins comprising an Fc part. Despite enhanced in vitro cell death induction of targeted scTRAIL molecules, however, comparable anti-tumor activities were found for the EGFR-targeting scFv-Fc-scTRAIL and the non-targeting Fc-scTRAIL in vivo.

    更新日期:2017-09-14
  • CCR5-dependent homing of T regulatory cells to the tumor microenvironment contributes to skin squamous cell carcinoma development
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-01-01
    Carine Ervolino de Oliveira, Thais Helena Gasparoto, Claudia Ramos Pinheiro, Nádia Ghinelli Amôr, Maria Renata Sales Nogueira, Ramon Kaneno, Gustavo Pompermaier Garlet, Vanessa Soares Lara, João Santana da Silva, Karen Angélica Cavassani, Ana Paula Campanelli

    Squamous cell carcinoma (SCC) is one of the most common human cancers worldwide. Recent studies show that regulatory T cells (Tregs) have a critical role in the modulation of an anti- tumor immune response, and consequently the SCC development. Since the accumulation of Tregs at the tumor site is, in part, due to selective recruitment through CCR5 and CCR5-associated chemokines, we investigated the role of CCR5 in the SCC development. Our findings showed that CCR5-deficient mice (CCR5KO) were efficient in controlling papilloma's incidence when compared with wild-type mice. Analysis of tumor lesions in wild-type (WT) and CCR5KO mice revealed that lack of CCR5 lead to significant reduction in frequency of Treg cells and increased of CD4 T cells into the tumors. Moreover, the adoptive transfer of naturally occurring Tregs CD4+CD25+CCR5+, CD4+CD25-CCR5+ or CD8+CCR5+ conventional T cells to CCR5KO mice resulted in an increased papilloma incidence. Interestingly, adoptive transfer of WT CD4+CD25+CCR5+ cells to CCR5KO mice induced more undifferentiated SCC lesions, characterized by higher infiltration of macrophages and dendritic cells. In the present study, we also demonstrated that Treg migration to the tumor microenvironment is mediated by CCR5, and these cells are promoting tumor growth via inhibition of anti-tumor cells such as cytotoxic CD8+ T cells. Our findings reinforce the therapeutic potential of CCR5 inhibition for cancer treatment, and indicate an attractive approach for SCC treatment.

    更新日期:2017-09-14
  • Basal-A Triple Negative Breast Cancer Cells Selectively Rely on RNA Splicing for Survival
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-01-01
    Stefanie Chan, Praveen Sridhar, Rory Kirchner, Ying Jie Lock, Zach Herbert, Silvia Buonamici, Peter Smith, Judy Lieberman, Fabio Petrocca

    Prognosis of triple-negative breast cancer (TNBC) remains poor. To identify shared and selective vulnerabilities of basal-like TNBC, the most common TNBC subtype, a directed siRNA lethality screen was performed in 7 human breast cancer cell lines, focusing on 154 previously identified dependency genes of one TNBC line. Thirty common dependency genes were identified, including multiple proteasome and RNA splicing genes, especially those associated with the U4/U6.U5 tri-snRNP complex (e.g., PRPF8, PRPF38A). PRPF8 or PRPF38A knockdown or the splicing modulator E7107 led to widespread intronic retention and altered splicing of transcripts involved in multiple basal-like TNBC dependencies, including protein homeostasis, mitosis and apoptosis. E7107 treatment suppressed the growth of basal-A TNBC cell line and patient-derived basal-like TNBC xenografts at a well-tolerated dose. The anti-tumor response was enhanced by adding the proteasome inhibitor bortezomib. Thus, inhibiting both splicing and the proteasome might be an effective approach for treating basal-like TNBC.

    更新日期:2017-09-07
  • Death by HDAC inhibition in synovial sarcoma cells
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-01-01
    Aimée N. Laporte, Neal M. Poulin, Jared J. Barrott, Xiu Qing Wang, Alireza Lorzadeh, Ryan Vander Werff, Kevin B. Jones, T. Michael Underhill, Torsten O. Nielsen

    Conventional cytotoxic therapies for synovial sarcoma provide limited benefit, and no drugs specifically targeting the causative SS18-SSX fusion oncoprotein are currently available. Histone deacetylase (HDAC) inhibition has been shown in previous studies to disrupt the synovial sarcoma oncoprotein complex, resulting in apoptosis. To understand the molecular effects of HDAC inhibition, RNA-Seq transcriptome analysis was undertaken in six human synovial sarcoma cell lines. HDAC inhibition induced pathways of cell cycle arrest, neuronal differentiation and response to oxygen-containing species, effects also observed in other cancers treated with this class of drugs. More specific to synovial sarcoma, polycomb-group targets were reactivated including tumor suppressor CDKN2A, and pro-apoptotic transcriptional patterns were induced. Functional analyses revealed that ROS-mediated FOXO activation and pro-apoptotic factors BIK, BIM and BMF were important to apoptosis induction following HDAC-inhibition in synovial sarcoma. HDAC-inhibitor pathway activation results in apoptosis and decreased tumor burden following a 7-day quisinostat treatment in the Ptenfl/fl;hSS2 mouse model of synovial sarcoma. This study provides mechanistic support for a particular susceptibility of synovial sarcoma to HDAC inhibition as a means of clinical treatment.

    更新日期:2017-09-07
  • Interleukin 4 receptor-targeted pro-apoptotic peptide blocks tumor growth and metastasis by enhancing anti-tumor immunity
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-01-01
    Sri Murugan Poongkavithai Vadevoo, Jung-Eun Kim, Gowri Rangaswamy Gunassekaran, Hyun-Kyung Jung, Lianhua Chi, Dong Eon Kim, Seung-Hyo Lee, Sin-Hyeog Im, Byungheon Lee

    Cellular crosstalk between tumors and M2-polarized tumor-associated macrophages (TAMs) favors tumor progression. Upregulation of interleukin 4 receptor (IL4R) is observed in diverse tumors and TAMs. We tested whether an IL4R-targeted pro-apoptotic peptide could inhibit tumor progression. The IL4R-binding peptide (IL4RPep-1) preferentially bound to IL4R-expressing tumor cells and M2-polarized macrophages both in vitro and in 4T1 breast tumors in vivo. To selectively kill IL4R-expressing cells, we designed an IL4R-targeted pro-apoptotic peptide, IL4RPep-1-K, by adding the pro-apoptotic peptide (KLAKLAK)2 to the end of IL4RPep-1. IL4RPep-1-K exerted selective cytotoxicity against diverse IL4R-expressing tumor cells and M2-polarized macrophages. Systemic administration of IL4RPep-1-K inhibited tumor growth and metastasis in 4T1 breast tumor-bearing mice. Interestingly, IL4RPep-1-K treatment increased the number of activated cytotoxic CD8+ T cells while reducing the numbers of immunosuppressive regulatory T cells and M2-polarized TAMs. No significant systemic side effects were observed. These results suggest that IL4R-targeted pro-apoptotic peptide has potential for treating diverse IL4R-expressing cancers.

    更新日期:2017-09-07
  • The p97 inhibitor CB-5083 is a unique disrupter of protein homeostasis in models of Multiple Myeloma.
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-01-01
    Ronan Le Moigne, Blake T. Aftab, Stevan Djakovic, Eugen Dhimolea, Eduardo Valle, Megan Murnane, Emily M. King, Ferdie Soriano, Mary-Kamala Menon, Zhi Yong Wu, Stephen T. Wong, Grace J. Lee, Bing Yao, Arun P. Wiita, Christine Lam, Julie Rice, Jinhai Wang, Marta Chesi, P. Leif Bergsagel, Marianne Kraus, Christoph Driessen, Szerenke Kiss von Soly, F. Michael Yakes, David Wustrow, Laura Shawver, Han-Jie Zhou, Thomas G. Martin, Jeffrey L. Wolf, Constantine S. Mitsiades, Daniel J. Anderson, Mark Rolfe

    Inhibition of the AAA ATPase, p97, was recently shown to be a novel method for targeting the ubiquitin proteasome system (UPS) and CB-5083, a first in class inhibitor of p97, has demonstrated broad antitumor activity in a range of both hematological and solid tumor models. Here, we show that CB-5083 has robust activity against multiple myeloma (MM) cell lines and a number of in vivo MM models. Treatment with CB-5083 is associated with accumulation of ubiquitinated proteins, induction of the unfolded protein response (UPR) and apoptosis. CB-5083 decreases viability in MM cell lines and patient derived MM cells, including those with background proteasome inhibitor (PI) resistance.  CB-5083 has a unique mechanism of action that combines well with PIs which is likely owing to the p97-dependent retro-translocation of the transcription factor, Nrf1, which transcribes proteasome subunit genes following exposure to a PI. In vivo studies using clinically relevant MM models demonstrate that single-agent CB-5083 inhibits tumor growth and combines well with MM standard of care agents. Our preclinical data demonstrate the efficacy of CB-5083 in several MM disease models and provide the rationale for clinical evaluation as monotherapy and in combination in MM.

    更新日期:2017-09-07
  • Highlights of This Issue
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-09-01
    American Association for Cancer Research

    ### [Dréan et al. Page 2022][1] PARP inhibitor (PARPi) resistance is often associated with “revertant” mutations that restore BRCA1 or BRCA2 gene function. Drean and colleagues used CRISPR-Cas9 mutagenesis to model these reversion mutations, finding that PARPi treatment selects for revertant

    更新日期:2017-09-05
  • Cotargeting of MEK and PDGFR/STAT3 Pathways to Treat Pancreatic Ductal Adenocarcinoma
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-09-01
    Nisebita Sahu, Emily Chan, Felix Chu, Thinh Pham, Hartmut Koeppen, William Forrest, Mark Merchant, Jeff Settleman

    Pancreatic ductal adenocarcinoma (PDAC) is among the most lethal human diseases and remains largely refractory to available drug treatments. Insufficient targeting of the known oncogenic drivers and activation of compensatory feedback loops and inability to prevent metastatic spread contribute to poor prognosis for this disease. The KRAS -driven MEK pathway is mutationally activated in most pancreatic cancers and is an important target for therapeutics. Using a two-dimensional monolayer culture system as well as three-dimensional spheroid culture system, we conducted a screen of a large panel of anticancer agents and found that MAP2K (MEK) inhibitors were most effective in targeting PDAC spheroids in comparison with monolayer cultures. Combination treatment with an MEK inhibitor and the multikinase inhibitor ponatinib was effective in targeting pancreatic cancer cells both in monolayer and spheroids by effectively blocking signaling via the PDGFRα and MEK kinases, while also preventing the activation of STAT3- and S6-mediated compensatory feedback loops in cancer cells. Furthermore, using xenograft models, we demonstrate that cotreatment with a MEK inhibitor and ponatinib causes significant tumor regression. PDAC patient samples also provided evidence of increased STAT3 activation in PDAC tumors and MAPK1 (ERK) activation in liver metastases, implicating STAT3 and ERK as key drivers in primary tumors and metastases, respectively. These results reveal a combination drug treatment strategy that may be effective in pancreatic cancer. Mol Cancer Ther; 16(9); 1729–38. ©2017 AACR . This article is featured in Highlights of This Issue, [p. 1727][1] [1]: /lookup/volpage/16/1727?iss=9

    更新日期:2017-09-05
  • Preclinical Efficacy and Molecular Mechanism of Targeting CDK7-Dependent Transcriptional Addiction in Ovarian Cancer
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-09-01
    Zhenfeng Zhang, Huixin Peng, Xiaojie Wang, Xia Yin, Pengfei Ma, Ying Jing, Mei-Chun Cai, Jin Liu, Meiying Zhang, Shengzhe Zhang, Kaixuan Shi, Wei-Qiang Gao, Wen Di, Guanglei Zhuang

    Ovarian cancer remains a significant cause of gynecologic cancer mortality, and novel therapeutic strategies are urgently needed in clinic as new treatment options. We previously showed that BET bromodomain inhibitors displayed promising efficacy for the treatment of epithelial ovarian cancer by downregulating pivot transcription factors. However, the potential antitumor activities and molecular mechanisms of other epigenetic or transcriptional therapies have not been systematically determined. Here, by performing an unbiased high-throughput drug screen to identify candidate compounds with antineoplastic effects, we identified THZ1, a recently developed covalent CDK7 inhibitor, as a new transcription-targeting compound that exerted broad cytotoxicity against ovarian tumors. Mechanistically, CDK7 represented a previously unappreciated actionable vulnerability in ovarian cancer, and CDK7 inhibition led to a pronounced dysregulation of gene transcription, with a preferential repression of E2F-regulated genes and transcripts associated with super-enhancers. Our findings revealed the molecular underpinnings of THZ1 potency and established pharmaceutically targeting transcriptional addiction as a promising therapeutic strategy in aggressive ovarian cancer. Mol Cancer Ther; 16(9); 1739–50. ©2017 AACR .

    更新日期:2017-09-05
  • CDK4/6 Inhibitors Sensitize Rb-positive Sarcoma Cells to Wee1 Kinase Inhibition through Reversible Cell-Cycle Arrest
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-09-01
    Ashleigh M. Francis, Angela Alexander, Yanna Liu, Smruthi Vijayaraghavan, Kwang Hui Low, Dong Yang, Tuyen Bui, Neeta Somaiah, Vinod Ravi, Khandan Keyomarsi, Kelly K. Hunt

    Research into the biology of soft tissue sarcomas has uncovered very few effective treatment strategies that improve upon the current standard of care which usually involves surgery, radiation, and chemotherapy. Many patients with large (>5 cm), high-grade sarcomas develop recurrence, and at that point have limited treatment options available. One challenge is the heterogeneity of genetic drivers of sarcomas, and many of these are not validated targets. Even when such genes are tractable targets, the rarity of each subtype of sarcoma makes advances in research slow. Here we describe the development of a synergistic combination treatment strategy that may be applicable in both soft tissue sarcomas as well as sarcomas of bone that takes advantage of targeting the cell cycle. We show that Rb-positive cell lines treated with the CDK4/6 inhibitor palbociclib reversibly arrest in the G1 phase of the cell cycle, and upon drug removal cells progress through the cell cycle as expected within 6–24 hours. Using a long-term high-throughput assay that allows us to examine drugs in different sequences or concurrently, we found that palbociclib-induced cell-cycle arrest poises Rb-positive sarcoma cells (SK-LMS1 and HT-1080) to be more sensitive to agents that work preferentially in S–G2 phase such as doxorubicin and Wee1 kinase inhibitors (AZD1775). The synergy between palbociclib and AZD1775 was also validated in vivo using SK-LMS1 xenografts as well as Rb-positive patient-derived xenografts (PDX) developed from leiomyosarcoma patients. This work provides the necessary preclinical data in support of a clinical trial utilizing this treatment strategy. Mol Cancer Ther; 16(9); 1751–64. ©2017 AACR .

    更新日期:2017-09-05
  • {beta}-Catenin Inhibitor BC2059 Is Efficacious as Monotherapy or in Combination with Proteasome Inhibitor Bortezomib in Multiple Myeloma
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-09-01
    Ioanna Savvidou, Tiffany Khong, Andrew Cuddihy, Catriona McLean, Stephen Horrigan, Andrew Spencer

    Currently available treatment options are unlikely to be curative for the majority of multiple myeloma patients, emphasizing a continuing role for the introduction of investigational agents that can overcome drug resistance. The canonical Wnt/β-catenin signaling pathway, essential for self-renewal, growth, and survival, has been found to be dysregulated in multiple myeloma, particularly in advanced stages of disease. This provides the rationale for evaluating the novel β-catenin inhibitor BC2059 as monotherapy and in combination with proteasome inhibitors in vitro and in vivo . Here, we show nuclear localization of β-catenin in human myeloma cell lines (HMCL), consistent with activation of the canonical Wnt pathway. BC2059 attenuates β-catenin levels, in both the cytoplasm and the nucleus, reducing the transcriptional activity of the TCF4/LEF complex and the expression of its target gene axin 2. Treatment of HMCL with BC2059 inhibits proliferation and induces apoptosis in a dose-dependent manner. This is also observed in HMCL–stromal cell cocultures, mitigating the protective effect afforded by the stroma. Similarly, BC2059 induces apoptosis in primary multiple myeloma samples in vitro , causing minimal apoptosis on healthy peripheral blood mononuclear cells. Furthermore, it synergizes with the proteasome inhibitor bortezomib both in HMCL and primary multiple myeloma samples. Finally, in xenograft models of human myelomatosis, BC2059 delays tumor growth and prolongs survival with minor on-target side effects. Collectively, these results demonstrate the efficacy of targeting the Wnt/β-catenin pathway with BC2059 both in vitro and in vivo , at clinically achievable doses. These findings support further clinical evaluation of BC2059 for the treatment of multiple myeloma. Mol Cancer Ther; 16(9); 1765–78. ©2017 AACR .

    更新日期:2017-09-05
  • Inhibition of Hsp90 Suppresses PI3K/AKT/mTOR Signaling and Has Antitumor Activity in Burkitt Lymphoma
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-09-01
    Lisa Giulino-Roth, Herman J. van Besien, Tanner Dalton, Jennifer E. Totonchy, Anna Rodina, Tony Taldone, Alexander Bolaender, Hediye Erdjument-Bromage, Jouliana Sadek, Amy Chadburn, Matthew J. Barth, Filemon S. Dela Cruz, Allison Rainey, Andrew L. Kung, Gabriela Chiosis, Ethel Cesarman

    Hsp90 is a molecular chaperone that protects proteins, including oncogenic signaling complexes, from proteolytic degradation. PU-H71 is a next-generation Hsp90 inhibitor that preferentially targets the functionally distinct pool of Hsp90 present in tumor cells. Tumors that are driven by the MYC oncoprotein may be particularly sensitive to PU-H71 due to the essential role of Hsp90 in the epichaperome, which maintains the malignant phenotype in the setting of MYC. Burkitt lymphoma (BL) is an aggressive B-cell lymphoma characterized by MYC dysregulation. In this study, we evaluated Hsp90 as a potential therapeutic target in BL. We found that primary BL tumors overexpress Hsp90 and that Hsp90 inhibition has antitumor activity in vitro and in vivo , including potent activity in a patient-derived xenograft model of BL. To evaluate the targets of PU-H71 in BL, we performed high-affinity capture followed by proteomic analysis using mass spectrometry. We found that Hsp90 inhibition targets multiple components of PI3K/AKT/mTOR signaling, highlighting the importance of this pathway in BL. Finally, we found that the anti-lymphoma activity of PU-H71 is synergistic with dual PI3K/mTOR inhibition in vitro and in vivo . Overall, this work provides support for Hsp90 as a therapeutic target in BL and suggests the potential for combination therapy with PU-H71 and inhibitors of PI3K/mTOR. Mol Cancer Ther; 16(9); 1779–90. ©2017 AACR .

    更新日期:2017-09-05
  • Discovery of a Novel Small-Molecule Inhibitor that Targets PP2A-{beta}-Catenin Signaling and Restricts Tumor Growth and Metastasis
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-09-01
    Shrankhla Maheshwari, Srinivasa R. Avula, Akhilesh Singh, L. Ravithej Singh, Gopala R. Palnati, Rakesh K. Arya, Srikanth H. Cheruvu, Sudhir Shahi, Tanuj Sharma, Sanjeev Meena, Anup K. Singh, Ruchir Kant, Mohammed Riyazuddin, Himangsu K. Bora, Mohammad I. Siddiqi, Jiaur R. Gayen, Koneni V. Sashidhara, Dipak Datta

    Molecular hybridization of different pharmacophores to tackle both tumor growth and metastasis by a single molecular entity can be very effective and unique if the hybrid product shows drug-like properties. Here, we report synthesis and discovery of a novel small-molecule inhibitor of PP2A–β-catenin signaling that limits both in vivo tumor growth and metastasis. Our molecular hybridization approach resulted in cancer cell selectivity and improved drug-like properties of the molecule. Inhibiting PP2A and β-catenin interaction by selectively engaging PR55α-binding site, our most potent small-molecule inhibitor diminished the expression of active β-catenin and its target proteins c-Myc and Cyclin D1. Furthermore, it promotes robust E-cadherin upregulation on the cell surface and increases β-catenin–E-Cadherin association, which may prevent dissemination of metastatic cells. Altogether, we report synthesis and mechanistic insight of a novel drug-like molecule to differentially target β-catenin functionality via interacting with a particular subunit of PP2A. Mol Cancer Ther; 16(9); 1791–805. ©2017 AACR .

    更新日期:2017-09-05
  • Metformin Synergizes with BCL-XL/BCL-2 Inhibitor ABT-263 to Induce Apoptosis Specifically in p53-Defective Cancer Cells
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-09-01
    Xinzhe Li, Bo Li, Zhenhong Ni, Peng Zhou, Bin Wang, Jintao He, Haojun Xiong, Fan Yang, Yaran Wu, Xilin Lyu, Yan Zhang, Yijun Zeng, Jiqin Lian, Fengtian He

    p53 deficiency, a frequent event in multiple kinds of malignancies, decreases the sensitivity of diverse targeted chemotherapeutics including the BCL-XL/BCL-2 inhibitor ABT-263. Loss of p53 function can activate mTOR complex 1 (mTORC1), which may make it a vulnerable target. Metformin has shown anti-neoplastic efficiency partially through suppressing mTORC1. However, it remains unknown whether mTORC1 activation confers ABT-263 resistance and whether metformin can overcome it in the p53-defective contexts. In this study, we for the first time demonstrated that metformin and ABT-263 synergistically elicited remarkable apoptosis through orchestrating the proapoptotic machineries in various p53-defective cancer cells. Mechanistic studies revealed that metformin sensitized ABT-263 via attenuating mTORC1-mediated cap-dependent translation of MCL-1 and survivin and weakening internal ribosome entry site (IRES)-dependent translation of XIAP . Meanwhile, ABT-263 sensitized metformin through disrupting the BCL-XL/BIM complex. However, metformin and ABT-263 had no synergistic killing effect in p53 wild-type (p53-WT) cancer cells because the cotreatment dramatically induced the senescence-associated secretory phenotype (SASP) in the presence of wild type p53, and SASP could aberrantly activate the AKT/ERK–mTORC1–4EBP1–MCL-1/survivin signaling axis. Blocking the axis using corresponding kinase inhibitors or neutralizing antibodies against different SASP components sensitized the cotreatment effect of metformin and ABT-263 in p53-WT cancer cells. The in vivo experiments showed that metformin and ABT-263 synergistically inhibited the growth of p53-defective (but not p53-WT) cancer cells in tumor xenograft nude mice. These results suggest that the combination of metformin and ABT-263 may be a novel targeted therapeutic strategy for p53-defective cancers. Mol Cancer Ther; 16(9); 1806–18. ©2017 AACR .

    更新日期:2017-09-05
  • Combination Treatment with Orlistat-Containing Nanoparticles and Taxanes Is Synergistic and Enhances Microtubule Stability in Taxane-Resistant Prostate Cancer Cells
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-09-01
    Joshua J. Souchek, Amanda L. Davis, Tanner K. Hill, Megan B. Holmes, Bowen Qi, Pankaj K. Singh, Steven J. Kridel, Aaron M. Mohs

    Taxane-based therapy provides a survival benefit in patients with metastatic prostate cancer, yet the median survival is less than 20 months in this setting due in part to taxane-associated resistance. Innovative strategies are required to overcome chemoresistance for improved patient survival. Here, NanoOrl, a new experimental nanoparticle formulation of the FDA-approved drug, orlistat, was investigated for its cytotoxicity in taxane-resistant prostate cancer utilizing two established taxane-resistant (TxR) cell lines. Orlistat is a weight loss drug that inhibits gastric lipases, but is also a potent inhibitor of fatty acid synthase (FASN), which is overexpressed in many types of cancer. NanoOrl was also investigated for its potential to synergize with taxanes in TxR cell lines. Both orlistat and NanoOrl synergistically inhibited cell viability when combined with paclitaxel, docetaxel, and cabazitaxel in PC3-TxR and DU145-TxR cells, yet these combinations were also additive in parental lines. We observed synergistic levels of apoptosis in TxR cells treated with NanoOrl and docetaxel in combination. Mechanistically, the synergy between orlistat and taxanes was independent of effects on the P-glycoprotein multidrug resistance protein, as determined by an efflux activity assay. On the other hand, immunoblot and immunofluorescence staining with an anti-detyrosinated tubulin antibody demonstrated that enhanced microtubule stability was induced by combined NanoOrl and docetaxel treatment in TxR cells. Furthermore, TxR cells exhibited higher lipid synthesis, as demonstrated by 14C-choline incorporation that was abrogated by NanoOrl. These results provide a strong rationale to assess the translational potential of NanoOrl to overcome taxane resistance. Mol Cancer Ther; 16(9); 1819–30. ©2017 AACR .

    更新日期:2017-09-05
  • Synthesis and Profiling of a Novel Potent Selective Inhibitor of CHK1 Kinase Possessing Unusual N-trifluoromethylpyrazole Pharmacophore Resistant to Metabolic N-dealkylation
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-09-01
    Pounami Samadder, Tereza Suchánková, Ondřej Hylse, Prashant Khirsariya, Fedor Nikulenkov, Stanislav Drápela, Nicol Straková, Petr Vaňhara, Kateřina Vašíčková, Hana Kolářová, Lucia Binó, Miroslava Bittová, Petra Ovesná, Peter Kollár, Radek Fedr, Milan Ešner, Josef Jaroš, Aleš Hampl, Lumír Krejčí, Kamil Paruch, Karel Souček

    Checkpoint-mediated dependency of tumor cells can be deployed to selectively kill them without substantial toxicity to normal cells. Specifically, loss of CHK1, a serine threonine kinase involved in the surveillance of the G2–M checkpoint in the presence of replication stress inflicted by DNA-damaging drugs, has been reported to dramatically influence the viability of tumor cells. CHK1′s pivotal role in maintaining genomic stability offers attractive opportunity for increasing the selectivity, effectivity, and reduced toxicity of chemotherapy. Some recently identified CHK1 inhibitors entered clinical trials in combination with DNA antimetabolites. Herein, we report synthesis and profiling of MU380, a nontrivial analogue of clinically profiled compound SCH900776 possessing the highly unusual N-trifluoromethylpyrazole motif, which was envisioned not to undergo metabolic oxidative dealkylation and thereby provide greater robustness to the compound. MU380 is a selective and potent inhibitor of CHK1 which sensitizes a variety of tumor cell lines to hydroxyurea or gemcitabine up to 10 times. MU380 shows extended inhibitory effects in cells, and unlike SCH900776, does not undergo in vivo N-dealkylation to the significantly less selective metabolite. Compared with SCH900776, MU380 in combination with GEM causes higher accumulation of DNA damage in tumor cells and subsequent enhanced cell death, and is more efficacious in the A2780 xenograft mouse model. Overall, MU380 represents a novel state-of-the-art CHK1 inhibitor with high potency, selectivity, and improved metabolic robustness to oxidative N-dealkylation. Mol Cancer Ther; 16(9); 1831–42. ©2017 AACR .

    更新日期:2017-09-05
  • ADA-07 Suppresses Solar Ultraviolet-Induced Skin Carcinogenesis by Directly Inhibiting TOPK
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-09-01
    Ge Gao, Tianshun Zhang, Qiushi Wang, Kanamata Reddy, Hanyong Chen, Ke Yao, Keke Wang, Eunmiri Roh, Tatyana Zykova, Weiya Ma, Joohyun Ryu, Clara Curiel-Lewandrowski, David Alberts, Sally E. Dickinson, Ann M. Bode, Ying Xing, Zigang Dong

    Cumulative exposure to solar ultraviolet (SUV) irradiation is regarded as the major etiologic factor in the development of skin cancer. The activation of the MAPK cascades occurs rapidly and is vital in the regulation of SUV-induced cellular responses. The T-LAK cell–originated protein kinase (TOPK), an upstream activator of MAPKs, is heavily involved in inflammation, DNA damage, and tumor development. However, the chemopreventive and therapeutic effects of specific TOPK inhibitors in SUV-induced skin cancer have not yet been elucidated. In the current study, ADA-07, a novel TOPK inhibitor, was synthesized and characterized. Pull-down assay results, ATP competition, and in vitro kinase assay data revealed that ADA-07 interacted with TOPK at the ATP-binding pocket and inhibited its kinase activity. Western blot analysis showed that ADA-07 suppressed SUV-induced phosphorylation of ERK1/2, p38, and JNKs and subsequently inhibited AP-1 activity. Importantly, topical treatment with ADA-07 dramatically attenuated tumor incidence, multiplicity, and volume in SKH-1 hairless mice exposed to chronic SUV. Our findings suggest that ADA-07 is a promising chemopreventive or potential therapeutic agent against SUV-induced skin carcinogenesis that acts by specifically targeting TOPK. Mol Cancer Ther; 16(9); 1843–54. ©2017 AACR .

    更新日期:2017-09-05
  • Antitumor Synergism and Enhanced Survival with a Tumor Vasculature-Targeted Enzyme Prodrug System, Rapamycin, and Cyclophosphamide
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-09-01
    John J. Krais, Needa Virani, Patrick H. McKernan, Quang Nguyen, Kar-Ming Fung, Vassilios I. Sikavitsas, Carla Kurkjian, Roger G. Harrison

    Mutant cystathionine gamma-lyase was targeted to phosphatidylserine exposed on tumor vasculature through fusion with Annexin A1 or Annexin A5. Cystathionine gamma-lyase E58N, R118L, and E338N mutations impart nonnative methionine gamma-lyase activity, resulting in tumor-localized generation of highly toxic methylselenol upon systemic administration of nontoxic selenomethionine. The described therapeutic system circumvents systemic toxicity issues using a novel drug delivery/generation approach and avoids the administration of nonnative proteins and/or DNA required with other enzyme prodrug systems. The enzyme fusion exhibits strong and stable in vitro binding with dissociation constants in the nanomolar range for both human and mouse breast cancer cells and in a cell model of tumor vascular endothelium. Daily administration of the therapy suppressed growth of highly aggressive triple-negative murine 4T1 mammary tumors in immunocompetent BALB/cJ mice and MDA-MB-231 tumors in SCID mice. Treatment did not result in the occurrence of negative side effects or the elicitation of neutralizing antibodies. On the basis of the vasculature-targeted nature of the therapy, combinations with rapamycin and cyclophosphamide were evaluated. Rapamycin, an mTOR inhibitor, reduces the prosurvival signaling of cells in a hypoxic environment potentially exacerbated by a vasculature-targeted therapy. IHC revealed, unsurprisingly, a significant hypoxic response (increase in hypoxia-inducible factor 1 α subunit, HIF1A) in the enzyme prodrug–treated tumors and a dramatic reduction of HIF1A upon rapamycin treatment. Cyclophosphamide, an immunomodulator at low doses, was combined with the enzyme prodrug therapy and rapamycin; this combination synergistically reduced tumor volumes, inhibited metastatic progression, and enhanced survival. Mol Cancer Ther; 16(9); 1855–65. ©2017 AACR . This article is featured in Highlights of This Issue, [p. 1727][1] [1]: /lookup/volpage/16/1727?iss=9

    更新日期:2017-09-05
  • A Potential Mechanism for ADC-Induced Neutropenia: Role of Neutrophils in Their Own Demise
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-09-01
    Hui Zhao, Sara Gulesserian, Maria Christina Malinao, Sathish Kumar Ganesan, James Song, Mi Sook Chang, Melissa M. Williams, Zhilan Zeng, Michael Mattie, Brian A. Mendelsohn, David R. Stover, Fernando Doñate

    Neutropenia is a common adverse event in cancer patients treated with antibody–drug conjugates (ADC) and we aimed to elucidate the potential mechanism of this toxicity. To investigate whether ADCs affect neutrophil production from bone marrow, an in vitro assay was developed in which hematopoietic stem cells (HSC) were differentiated to neutrophils. Several antibodies against targets absent in HSCs and neutrophils were conjugated to MMAE via a cleavable valine-citrulline linker (vcMMAE-ADC) or MMAF via a noncleavable maleimidocaproyl linker (mcMMAF-ADC), and their cytotoxicity was tested in the neutrophil differentiation assay. Results showed that HSCs had similar sensitivity to vcMMAE-ADCs and mcMMAF-ADCs; however, vcMMAE-ADCs were more cytotoxic to differentiating neutrophils than the same antibody conjugated to mcMMAF. This inhibitory effect was not mediated by internalization of ADC either by macropinocytosis or FcγRs. Our results suggested that extracellular proteolysis of the cleavable valine-citrulline linker is responsible for the cytotoxicity to differentiating neutrophils. Mass spectrometry analyses indicated that free MMAE was released from vcMMAE-ADCs in the extracellular compartment when they were incubated with differentiating neutrophils or neutrophil conditioned medium, but not with HSC-conditioned medium. Using different protease inhibitors, our data suggested that serine, but not cysteine proteases, were responsible for the cleavage. In vitro experiments demonstrated that the purified serine protease, elastase, was capable of releasing free MMAE from a vcMMAE-ADC. Here we propose that ADCs containing protease cleavable linkers can contribute to neutropenia via extracellular cleavage mediated by serine proteases secreted by differentiating neutrophils in bone marrow. Mol Cancer Ther; 16(9); 1866–76. ©2017 AACR . See related article by Zhao et al., [p. 1877][1] This article is featured in Highlights of This Issue, [p. 1727][2] [1]: /lookup/volpage/16/1877?iss=9 [2]: /lookup/volpage/16/1727?iss=9

    更新日期:2017-09-05
  • Inhibition of Megakaryocyte Differentiation by Antibody-Drug Conjugates (ADCs) is Mediated by Macropinocytosis: Implications for ADC-induced Thrombocytopenia
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-09-01
    Hui Zhao, Sara Gulesserian, Sathish Kumar Ganesan, Jimmy Ou, Karen Morrison, Zhilan Zeng, Veronica Robles, Josh Snyder, Lisa Do, Hector Aviña, Sher Karki, David R. Stover, Fernando Doñate

    Thrombocytopenia is a common adverse event in cancer patients treated with antibody–drug conjugates (ADC), including AGS-16C3F, an ADC targeting ENPP3 (ectonucleotide pyrophosphatase/phosphodiesterase-3) and trastuzumab emtansine (T-DM1). This study aims to elucidate the mechanism of action of ADC-induced thrombocytopenia. ENPP3 expression in platelets and megakaryocytes (MK) was investigated and shown to be negative. The direct effect of AGS-16C3F on platelets was evaluated using platelet rich plasma following the expression of platelet activation markers. Effects of AGS-16C3F, T-DM1, and control ADCs on maturing megakaryocytes were evaluated in an in vitro system in which human hematopoietic stem cells (HSC) were differentiated into MKs. AGS-16C3F, like T-DM1, did not affect platelets directly, but inhibited MK differentiation by the activity of Cys-mcMMAF, its active metabolite. FcγRIIA did not appear to play an important role in ADC cytotoxicity to differentiating MKs. AGS-16C3F, cytotoxic to MKs, did not bind to FcγRIIA on MKs. Blocking the interaction of T-DM1 with FcγRIIA did not prevent the inhibition of MK differentiation and IgG1-mcMMAF was not as cytotoxic to MKs despite binding to FcγRIIA. Several lines of evidence suggest that internalization of AGS-16C3F into MKs is mediated by macropinocytosis. Macropinocytosis activity of differentiating HSCs correlated with cell sensitivity to AGS-16C3F. AGS-16C3F was colocalized with a macropinocytosis marker, dextran-Texas Red in differentiating MKs. Ethyl isopropyl amiloride (EIPA), a macropinocytosis inhibitor, blocked internalization of dextran-Texas Red and AGS-16C3F. These data support the notion that inhibition of MK differentiation via macropinocytosis-mediated internalization plays a role in ADC-induced thrombocytopenia. Mol Cancer Ther; 16(9); 1877–86. ©2017 AACR . See related article by Zhao et al., [p. 1866][1] [1]: /lookup/volpage/16/1866?iss=9

    更新日期:2017-09-05
  • Enzymatic Inactivation of Endogenous IgG by IdeS Enhances Therapeutic Antibody Efficacy
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-09-01
    Sofia Järnum, Anna Runström, Robert Bockermann, Lena Winstedt, Max Crispin, Christian Kjellman

    Endogenous plasma IgG sets an immunologic threshold that dictates the activity of tumor-directed therapeutic antibodies. Saturation of cellular antibody receptors by endogenous antibody limits antibody-dependent cell-mediated cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP). Here, we show how enzymatic cleavage of IgG using the bacterial enzyme IdeS can be utilized to empty both high and low affinity Fcγ-receptors and clear the entire endogenous antibody pool. Using in vitro models, tumor animal models as well as ex vivo analysis of sera collected during a previous clinical trial with IdeS, we show how clearing of competing plasma antibody levels with IdeS unblocks cellular antibody receptors. We show that therapeutic antibodies against breast cancer (trastuzumab), colon cancer (cetuximab), and lymphomas (rituximab and alemtuzumab) can be potentiated when endogenous IgG is removed. Overall, IdeS is shown to be a potent tool to reboot the human antibody repertoire and to generate a window to preferentially load therapeutic antibodies onto effector cells and thereby create an armada of dedicated tumor-seeking immune cells. Mol Cancer Ther; 16(9); 1887–97. ©2017 AACR .

    更新日期:2017-09-05
  • IL6 Receptor Blockade Enhances Chemotherapy Efficacy in Pancreatic Ductal Adenocarcinoma
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-09-01
    Kristen B. Long, Graham Tooker, Evan Tooker, Santiago Lombo Luque, Jae W. Lee, Xiaoqing Pan, Gregory L. Beatty

    Inflammation mediated by activation of JAK/STAT signaling is a major cause of chemotherapy resistance in cancer. We studied the impact of selectively blocking the IL6 receptor (IL6R) as a strategy to inhibit IL6-induced STAT activation and to overcome chemoresistance in pancreatic ductal adenocarcinoma (PDAC). To do this, STAT activation was investigated in tumors arising spontaneously in LSL-KrasG12D/+;LSL-Trp53R172H/+;Pdx-1Cre (KPC) mice. Plasma from patients with PDAC was assessed for its ability to activate STAT3/SOCS3 in human monocytes using immunofluorescence microscopy and quantitative gene expression assays. KPC mice and syngeneic mice (wild type and IL6−/−) implanted with KPC-derived cell lines were treated with an IL6R-blocking antibody (anti-IL6R). The impact of treatment on tumor growth in KPC mice and mice with KPC-derived tumor implants was monitored using ultrasonography and calipers, respectively. Tumors were analyzed by IHC to detect changes in STAT activation, tumor viability, and proliferation. We found that STAT3 was the most activated STAT protein in PDAC tumors from KPC mice. Plasma from patients with advanced PDAC stimulated STAT3/SOCS3 activation in human monocytes. In mice, anti-IL6R antibodies targeted Ly6Chi monocytes, inhibited STAT3 activation in tumor cells, and decreased tumor cell proliferation in vivo . IL6R blockade in combination with chemotherapy induced tumor cell apoptosis, tumor regressions, and improved overall survival. Overall, we show that IL6 signaling drives STAT3 activation in tumor cells and mediates chemoresistance in PDAC. Thus, disrupting IL6 signaling using anti-IL6R antibodies holds promise for improving chemotherapy efficacy in PDAC. Mol Cancer Ther; 16(9); 1898–908. ©2017 AACR .

    更新日期:2017-09-05
  • A Novel Theranostic Strategy for MMP-14-Expressing Glioblastomas Impacts Survival
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-09-01
    Suchismita Mohanty, Zixin Chen, Kai Li, Goreti Ribeiro Morais, Jessica Klockow, Ketan Yerneni, Laura Pisani, Frederick T. Chin, Siddharta Mitra, Samuel Cheshier, Edwin Chang, Sanjiv Sam Gambhir, Jianghong Rao, Paul M. Loadman, Robert A. Falconer, Heike E. Daldrup-Link

    Glioblastoma (GBM) has a dismal prognosis. Evidence from preclinical tumor models and human trials indicates the role of GBM-initiating cells (GIC) in GBM drug resistance. Here, we propose a new treatment option with tumor enzyme-activatable, combined therapeutic and diagnostic (theranostic) nanoparticles, which caused specific toxicity against GBM tumor cells and GICs. The theranostic cross-linked iron oxide nanoparticles (CLIO) were conjugated to a highly potent vascular disrupting agent (ICT) and secured with a matrix-metalloproteinase (MMP-14) cleavable peptide. Treatment with CLIO-ICT disrupted tumor vasculature of MMP-14 –expressing GBM, induced GIC apoptosis, and significantly impaired tumor growth. In addition, the iron core of CLIO-ICT enabled in vivo drug tracking with MR imaging. Treatment with CLIO-ICT plus temozolomide achieved tumor remission and significantly increased survival of human GBM-bearing mice by more than 2-fold compared with treatment with temozolomide alone. Thus, we present a novel therapeutic strategy with significant impact on survival and great potential for clinical translation. Mol Cancer Ther; 16(9); 1909–21. ©2017 AACR .

    更新日期:2017-09-05
  • Herpes Simplex Virus Glycoprotein D Targets a Specific Dendritic Cell Subset and Improves the Performance of Vaccines to Human Papillomavirus-Associated Tumors
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-09-01
    Bruna F.M.M. Porchia, Ana Carolina R. Moreno, Rodrigo N. Ramos, Mariana O. Diniz, Laís Helena T.M. de Andrade, Daniela S. Rosa, José Alexandre M. Barbuto, Silvia B. Boscardin, Luís Carlos S. Ferreira

    Cervical cancer is a major public health problem and one of the leading causes of cancer deaths in women. Virtually all cases of cervical cancer, as well as a growing share of anal and head/neck tumors, are associated with human papillomavirus (HPV) infection. Despite the effectiveness, the available prophylactic vaccines do not benefit women with cervical lesions or cancer. Therefore, the search of new immunotherapeutic approaches to treat HPV-induced tumors is still a priority. The present study characterizes a therapeutic antitumor vaccine based on the genetic fusion of the Herpes simplex virus-1 (HSV-1) glycoprotein D (gD) with the E7 oncoprotein from HPV-16 (gDE7). Two subcutaneous doses of gDE7, admixed with poly (I:C), conferred complete and long-lasting therapeutic antitumor protection on mice previously challenged with tumor cells expressing the HPV-16 oncoproteins. The vaccine induced multifunctional E7-specific CD8+ T cells with cytotoxic activity and effector memory phenotype (CD44+ CD62Llow). In addition, gDE7 admixed with poly (I:C) vaccination controlled the expansion of tumor-induced regulatory T cells and myeloid-derived suppressor cells. More importantly, gDE7 activated mouse CD11c+ CD8α+ and human BDCA3+ dendritic cells (DC), specialized in antigen cross-presentation to CD8+ T cells, under in vitro conditions. These results indicated that the activation of a specific DC population, mediated by gD, improved the antigen-specific immune responses and the therapeutic performance induced by antitumor vaccines. These results open perspectives for the clinical testing of gDE7-based vaccines under the concept of active immunization as a tool for the therapeutic control of cancer. Mol Cancer Ther; 16(9); 1922–33. ©2017 AACR .

    更新日期:2017-09-05
  • Inhibition of Aurora A and Aurora B Is Required for the Sensitivity of HPV-Driven Cervical Cancers to Aurora Kinase Inhibitors
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-09-01
    David Martin, Sora Fallaha, Martina Proctor, Alexander Stevenson, Lewis Perrin, Nigel McMillan, Brian Gabrielli

    The activity and efficacy of Aurora inhibitors have been reported in a wide range of cancer types. The most prominent Aurora inhibitor is alisertib, an investigational Aurora inhibitor that has been the subject of more than 30 clinical trials. Alisertib has inhibitory activity against both Aurora A and B, although it is considered to be primarily an Aurora A inhibitor in vivo . Here, we show that alisertib inhibits both Aurora A and B in vivo in preclinical models of HPV-driven cervical cancer, and that it is the inhibition of Aurora A and B that provides the selectivity and efficacy of this drug in vivo in this disease setting. We also present formal evidence that alisertib requires progression through mitosis for its efficacy, and that it is unlikely to combine with drugs that promote a G2 DNA damage checkpoint response. This work demonstrates that inhibition of Aurora A and B is required for effective control of HPV-driven cancers by Aurora kinase inhibitors. Mol Cancer Ther; 16(9); 1934–41. ©2017 AACR .

    更新日期:2017-09-05
  • mTORC1 Inhibition Induces Resistance to Methotrexate and 6-Mercaptopurine in Ph+ and Ph-like B-ALL
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-09-01
    Thanh-Trang T. Vo, J. Scott Lee, Duc Nguyen, Brandon Lui, William Pandori, Andrew Khaw, Sharmila Mallya, Mengrou Lu, Markus Müschen, Marina Konopleva, David A. Fruman

    Elevated activity of mTOR is associated with poor prognosis and higher incidence of relapse in B-cell acute lymphoblastic leukemia (B-ALL). Thus, ongoing clinical trials are testing mTOR inhibitors in combination with chemotherapy in B-ALL. However, the combination of mTOR inhibitors with standard of care chemotherapy drugs has not been studied extensively in high-risk B-ALL subtypes. Therefore, we tested whether mTOR inhibition can augment the efficacy of current chemotherapy agents in Ph+ and Ph-like B-ALL models. Surprisingly, inhibiting mTOR complex 1 (mTORC1) protected B-ALL cells from killing by methotrexate and 6-mercaptopurine, two antimetabolite drugs used in maintenance chemotherapy. The cytoprotective effects correlated with decreased cell-cycle progression and were recapitulated using cell-cycle inhibitors, palbociclib or aphidicolin. Dasatinib, a tyrosine kinase inhibitor currently used in Ph+ patients, inhibits ABL kinase upstream of mTOR. Dasatinib resistance is mainly caused by ABL kinase mutations, but is also observed in a subset of ABL unmutated cases. We identified dasatinib-resistant Ph+ cell lines and patient samples in which dasatinib can effectively reduce ABL kinase activity and mTORC1 signaling without causing cell death. In these cases, dasatinib protected leukemia cells from killing by 6-mercaptopurine. Using xenograft models, we observed that mTOR inhibition or dasatinib increased the numbers of leukemia cells that emerge after cessation of chemotherapy treatment. These results demonstrate that inhibitors targeting mTOR or upstream signaling nodes should be used with caution when combined with chemotherapeutic agents that rely on cell-cycle progression to kill B-ALL cells. Mol Cancer Ther; 16(9); 1942–53. ©2017 AACR .

    更新日期:2017-09-05
  • Wnt/{beta}-catenin Signaling Contributes to Tumor Malignancy and Is Targetable in Gastrointestinal Stromal Tumor
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-09-01
    Shan Zeng, Adrian M. Seifert, Jennifer Q. Zhang, Michael J. Cavnar, Teresa S. Kim, Vinod P. Balachandran, Juan A. Santamaria-Barria, Noah A. Cohen, Michael J. Beckman, Benjamin D. Medina, Ferdinand Rossi, Megan H. Crawley, Jennifer K. Loo, Joanna H. Maltbaek, Peter Besmer, Cristina R. Antonescu, Ronald P. DeMatteo

    Gastrointestinal stromal tumor (GIST) is the most common type of sarcoma and usually harbors either a KIT or PDGFRA mutation. However, the molecular basis for tumor malignancy is not well defined. Although the Wnt/β-catenin signaling pathway is important in a variety of cancers, its role in GIST is uncertain. Through analysis of nearly 150 human GIST specimens, we found that some human GISTs expressed β-catenin and contained active, dephosphorylated nuclear β-catenin. Furthermore, advanced human GISTs expressed reduced levels of the Wnt antagonist DKK4. Accordingly, in human GIST T1 cells, Wnt stimulation increased β-catenin–mediated transcriptional activity in a reporter assay as well as transcription of the downstream target genes Axin2 and CCND1 . In contrast, DKK4 overexpression in GIST T1 cells reduced Wnt/β-catenin signaling. In addition, we showed that nuclear β-catenin stability was partially regulated by the E3 ligase COP1, as demonstrated with coimmunoprecipitation and COP1 knockdown. Three molecular inhibitors of the Wnt/β-catenin pathway demonstrated antitumor efficacy in various GIST models, both in vitro and in vivo . Notably, the tankyrase inhibitor G007-LK alone had substantial activity against tumors of genetically engineered KitV558Δ/+ mice, and the effect was increased by the addition of the Kit inhibitor imatinib mesylate. Collectively, our findings demonstrate that Wnt/β-catenin signaling is a novel therapeutic target for selected untreated or imatinib-resistant GISTs. Mol Cancer Ther; 16(9); 1954–66. ©2017 AACR .

    更新日期:2017-09-05
  • An In Vivo Functional Screen Identifies JNK Signaling As a Modulator of Chemotherapeutic Response in Breast Cancer
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-09-01
    Matthew Ashenden, Antoinette van Weverwijk, Nirupa Murugaesu, Antony Fearns, James Campbell, Qiong Gao, Marjan Iravani, Clare M. Isacke

    Chemotherapy remains the mainstay of treatment for advanced breast cancer; however, resistance is an inevitable event for the majority of patients with metastatic disease. Moreover, there is little information available to guide stratification of first-line chemotherapy, crucial given the common development of multidrug resistance. Here, we describe an in vivo screen to interrogate the response to anthracycline-based chemotherapy in a syngeneic metastatic breast cancer model and identify JNK signaling as a key modulator of chemotherapy response. Combining in vitro and in vivo functional analyses, we demonstrate that JNK inhibition both promotes tumor cell cytostasis and blocks activation of the proapoptotic protein Bax, thereby antagonizing chemotherapy-mediated cytotoxicity. To investigate the clinical relevance of this dual role of JNK signaling, we developed a proliferation-independent JNK activity signature and demonstrate high JNK activity to be enriched in triple-negative and basal-like breast cancer subtypes. Consistent with the dual role of JNK signaling in vitro , high-level JNK pathway activation in triple-negative breast cancers is associated both with poor patient outcome in the absence of chemotherapy treatment and, in neoadjuvant clinical studies, is predictive of enhanced chemotherapy response. These data highlight the potential of monitoring JNK activity as early biomarker of response to chemotherapy and emphasize the importance of rational treatment regimes, particularly when combining cytostatic and chemotherapeutic agents. Mol Cancer Ther; 16(9); 1967–78. ©2017 AACR .

    更新日期:2017-09-05
  • FBW7-Dependent Mcl-1 Degradation Mediates the Anticancer Effect of Hsp90 Inhibitors
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-09-01
    Jingshan Tong, Shuai Tan, Zaneta Nikolovska-Coleska, Jian Yu, Fangdong Zou, Lin Zhang

    Heat shock protein 90 (Hsp90) is widely overexpressed in cancer cells and necessary for maintenance of malignant phenotypes. Hsp90 inhibition induces tumor cell death through degradation of its client oncoproteins and has shown promises in preclinical studies. However, the mechanism by which Hsp90 inhibitors kill tumor cells is not well-understood. Biomarkers associated with differential sensitivity and resistance to Hsp90 inhibitors remain to be identified. In this study, we found that colorectal cancer cells containing inactivating mutations of FBW7 , a tumor suppressor and E3 ubiquitin ligase, are intrinsically insensitive to Hsp90 inhibitors. The insensitive colorectal cancer cells lack degradation of Mcl-1, a prosurvival Bcl-2 family protein. Hsp90 inhibition promotes GSK3β-dependent phosphorylation of Mcl-1, which subsequently binds to FBW7 and undergoes ubiquitination and proteasomal degradation. Specifically blocking Mcl-1 phosphorylation by genetic knock-in abrogates its degradation and renders in vitro and in vivo resistance to Hsp90 inhibitors, which can be overcame by Mcl-1–selective small-molecule inhibitors. Collectively, our findings demonstrate a key role of GSK3β/FBW7-dependent Mcl-1 degradation in killing of colorectal cancer cells by Hsp90 inhibitors and suggest FBW7 mutational status as a biomarker for Hsp90-targeted therapy. Mol Cancer Ther; 16(9); 1979–88. ©2017 AACR .

    更新日期:2017-09-05
  • Tyrosine Kinase Inhibitors Protect the Salivary Gland from Radiation Damage by Inhibiting Activation of Protein Kinase C-{delta}
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-09-01
    Sten M. Wie, Elizabeth Wellberg, Sana D. Karam, Mary E. Reyland

    In patients undergoing irradiation (IR) therapy, injury to nontumor tissues can result in debilitating, and sometimes permanent, side effects. We have defined protein kinase C-δ (PKCδ) as a regulator of DNA damage–induced apoptosis and have shown that phosphorylation of PKCδ by c-Abl and c-Src activates its proapoptotic function. Here, we have explored the use of tyrosine kinase inhibitors (TKI) of c-Src and c-Abl to block activation of PKCδ for radioprotection of the salivary gland. Dasatinib, imatinib, and bosutinib all suppressed tyrosine phosphorylation of PKCδ and inhibited IR-induced apoptosis in vitro . To determine whether TKIs can provide radioprotection of salivary gland function in vivo , mice were treated with TKIs and a single or fractionated doses of irradiation. Delivery of dasatinib or imatinib within 3 hours of a single or fractionated dose of irradiation resulted in >75% protection of salivary gland function at 60 days. Continuous dosing with dasatinib extended protection to at least 5 months and correlated with histologic evidence of salivary gland acinar cell regeneration. Pretreatment with TKIs had no impact on clonogenic survival of head and neck squamous cell carcinoma (HNSCC) cells, and in mice harboring HNSCC cell–derived xenografts, combining dasatinib or imatinib with fractionated irradiation did not enhance tumor growth. Our studies indicate that TKIs may be useful clinically to protect nontumor tissue in HNC patients undergoing radiotherapy, without negatively impacting cancer treatment. Mol Cancer Ther; 16(9); 1989–98. ©2017 AACR .

    更新日期:2017-09-05
  • Optimization of RAS/BRAF Mutational Analysis Confirms Improvement in Patient Selection for Clinical Benefit to Anti-EGFR Treatment in Metastatic Colorectal Cancer
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-09-01
    Cristina Santos, Daniel Azuara, Rocio Garcia-Carbonero, Pilar Garcia Alfonso, Alfredo Carrato, Mª Elena Elez, Auxiliadora Gomez, Ferran Losa, Clara Montagut, Bartomeu Massuti, Valenti Navarro, Mar Varela, Adriana Lopez-Doriga, Victor Moreno, Manuel Valladares, Jose Luis Manzano, Jose Maria Vieitez, Enrique Aranda, Xavier Sanjuan, Josep Tabernero, Gabriel Capella, Ramon Salazar

    In metastatic colorectal cancer (mCRC), recent studies have shown the importance to accurately quantify low-abundance mutations of the RAS pathway because anti-EGFR therapy may depend on certain mutation thresholds. We aimed to evaluate the added predictive value of an extended RAS panel testing using two commercial assays and a highly sensitive and quantitative digital PCR (dPCR). Tumor samples from 583 mCRC patients treated with anti–EGFR- ( n = 255) or bevacizumab- ( n = 328) based therapies from several clinical trials and retrospective series from the TTD/RTICC Spanish network were analyzed by cobas, therascreen , and dPCR. We evaluated concordance between techniques using the Cohen kappa index. Response rate, progression-free survival (PFS), and overall survival (OS) were correlated to the mutational status and the mutant allele fraction (MAF). Concordance between techniques was high when analyzing RAS and BRAF (Cohen kappa index around 0.75). We observed an inverse correlation between MAF and response in the anti-EGFR cohort ( P < 0.001). Likelihood ratio analysis showed that a fraction of 1% or higher of any mutated alleles offered the best predictive value. PFS and OS were significantly longer in RAS / BRAF wild-type patients, independently of the technique. However, the predictability of both PFS and OS were higher when we considered a threshold of 1% in the RAS scenario (HR = 1.53; CI 95%, 1.12–2.09 for PFS, and HR = 1.9; CI 95%, 1.33–2.72 for OS). Although the rate of mutations observed among techniques is different, RAS and BRAF mutational analysis improved prediction of response to anti-EGFR therapy. Additionally, dPCR with a threshold of 1% outperformed the other platforms. Mol Cancer Ther; 16(9); 1999–2007. ©2017 AACR .

    更新日期:2017-09-05
  • Cooperative Targets of Combined mTOR/HDAC Inhibition Promote MYC Degradation
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-09-01
    John K. Simmons, Aleksandra M. Michalowski, Benjamin J. Gamache, Wendy DuBois, Jyoti Patel, Ke Zhang, Joy Gary, Shuling Zhang, Snehal Gaikwad, Daniel Connors, Nicholas Watson, Elena Leon, Jin-Qiu Chen, W. Michael Kuehl, Maxwell P. Lee, Adriana Zingone, Ola Landgren, Peter Ordentlich, Jing Huang, Beverly A. Mock

    Cancer treatments often require combinations of molecularly targeted agents to be effective. mTORi (rapamycin) and HDACi (MS-275/entinostat) inhibitors have been shown to be effective in limiting tumor growth, and here we define part of the cooperative action of this drug combination. More than 60 human cancer cell lines responded synergistically (CI<1) when treated with this drug combination compared with single agents. In addition, a breast cancer patient–derived xenograft, and a BCL-XL plasmacytoma mouse model both showed enhanced responses to the combination compared with single agents. Mice bearing plasma cell tumors lived an average of 70 days longer on combination treatment compared with single agents. A set of 37 genes cooperatively affected (34 downregulated; 3 upregulated) by the combination responded pharmacodynamically in human myeloma cell lines, xenografts, and a P493 model, and were both enriched in tumors, and correlated with prognostic markers in myeloma patient datasets. Genes downregulated by the combination were overexpressed in several untreated cancers (breast, lung, colon, sarcoma, head and neck, myeloma) compared with normal tissues. The MYC/E2F axis, identified by upstream regulator analyses and validated by immunoblots, was significantly inhibited by the drug combination in several myeloma cell lines. Furthermore, 88% of the 34 genes downregulated have MYC-binding sites in their promoters, and the drug combination cooperatively reduced MYC half-life by 55% and increased degradation. Cells with MYC mutations were refractory to the combination. Thus, integrative approaches to understand drug synergy identified a clinically actionable strategy to inhibit MYC/E2F activity and tumor cell growth in vivo . Mol Cancer Ther; 16(9); 2008–21. ©2017 AACR .

    更新日期:2017-09-05
  • Modeling Therapy Resistance in BRCA1/2-Mutant Cancers
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-09-01
    Amy Dréan, Chris T. Williamson, Rachel Brough, Inger Brandsma, Malini Menon, Asha Konde, Isaac Garcia-Murillas, Helen N. Pemberton, Jessica Frankum, Rumana Rafiq, Nicholas Badham, James Campbell, Aditi Gulati, Nicholas C. Turner, Stephen J. Pettitt, Alan Ashworth, Christopher J. Lord

    Although PARP inhibitors target BRCA1 - or BRCA2 -mutant tumor cells, drug resistance is a problem. PARP inhibitor resistance is sometimes associated with the presence of secondary or “revertant” mutations in BRCA1 or BRCA2 . Whether secondary mutant tumor cells are selected for in a Darwinian fashion by treatment is unclear. Furthermore, how PARP inhibitor resistance might be therapeutically targeted is also poorly understood. Using CRISPR mutagenesis, we generated isogenic tumor cell models with secondary BRCA1 or BRCA2 mutations. Using these in heterogeneous in vitro culture or in vivo xenograft experiments in which the clonal composition of tumor cell populations in response to therapy was monitored, we established that PARP inhibitor or platinum salt exposure selects for secondary mutant clones in a Darwinian fashion, with the periodicity of PARP inhibitor administration and the pretreatment frequency of secondary mutant tumor cells influencing the eventual clonal composition of the tumor cell population. In xenograft studies, the presence of secondary mutant cells in tumors impaired the therapeutic effect of a clinical PARP inhibitor. However, we found that both PARP inhibitor–sensitive and PARP inhibitor–resistant BRCA2 mutant tumor cells were sensitive to AZD-1775, a WEE1 kinase inhibitor. In mice carrying heterogeneous tumors, AZD-1775 delivered a greater therapeutic benefit than olaparib treatment. This suggests that despite the restoration of some BRCA1 or BRCA2 gene function in “revertant” tumor cells, vulnerabilities still exist that could be therapeutically exploited. Mol Cancer Ther; 16(9); 2022–34. ©2017 AACR . This article is featured in Highlights of This Issue, [p. 1727][1] [1]: /lookup/volpage/16/1727?iss=9

    更新日期:2017-09-05
  • Metformin Inhibits Cellular Proliferation and Bioenergetics in Colorectal Cancer Patient-Derived Xenografts
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-09-01
    Nur-Afidah Mohamed Suhaimi, Wai Min Phyo, Hao Yun Yap, Sharon Heng Yee Choy, Xiaona Wei, Yukti Choudhury, Wai Jin Tan, Luke Anthony Peng Yee Tan, Roger Sik Yin Foo, Suzanne Hui San Tan, Zenia Tiang, Chin Fong Wong, Poh Koon Koh, Min-Han Tan

    There is increasing preclinical evidence suggesting that metformin, an antidiabetic drug, has anticancer properties against various malignancies, including colorectal cancer. However, the majority of evidence, which was derived from cancer cell lines and xenografts, was likely to overestimate the benefit of metformin because these models are inadequate and require supraphysiologic levels of metformin. Here, we generated patient-derived xenograft (PDX) lines from 2 colorectal cancer patients to assess the properties of metformin and 5-fluorouracil (5-FU), the first-line drug treatment for colorectal cancer. Metformin (150 mg/kg) as a single agent inhibits the growth of both PDX tumors by at least 50% ( P < 0.05) when administered orally for 24 days. In one of the PDX models, metformin given concurrently with 5-FU (25 mg/kg) leads to an 85% ( P = 0.054) growth inhibition. Ex vivo culture of organoids generated from PDX demonstrates that metformin inhibits growth by executing metabolic changes to decrease oxygen consumption and activating AMPK-mediated pathways. In addition, we also performed genetic characterizations of serial PDX samples with corresponding parental tissues from patients using next-generation sequencing (NGS). Our pilot NGS study demonstrates that PDX represents a useful platform for analysis in cancer research because it demonstrates high fidelity with parental tumor. Furthermore, NGS analysis of PDX may be useful to determine genetic identifiers of drug response. This is the first preclinical study using PDX and PDX-derived organoids to investigate the efficacy of metformin in colorectal cancer. Mol Cancer Ther; 16(9); 2035–44. ©2017 AACR .

    更新日期:2017-09-05
  • A CRISPR/Cas9-based screening for non-homologous end joining inhibitors reveals ouabain and penfluridol as radiosensitizers
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-01-01
    Jie Du, Jun Shang, Fei Chen, Yushuo Zhang, Narui Yin, Ting Xie, Haowen Zhang, Jiahua Yu, Fenju Liu

    Non-homologous end joining (NHEJ) is the major pathway responsible for the repair of ionizing radiation (IR)-induced DNA double-strand breaks (DSBs), and correspondingly regulates the cellular response to IR. Identification of NHEJ inhibitors could substantially enhance the tumor radiosensitivity and improve the therapeutic efficiency of radiotherapy. In present study, we demonstrated a screening for NHEJ inhibitors by using the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system and high-resolution melting (HRM) analysis. Since NHEJ is regarded as an error-prone mechanism, the NHEJ-mediated ligation of the site-specific DSB induced by Cas9 nuclease would eventually cause the mutation of the targeted sequence. Then, HRM analysis, a reliable and rapid assay for detecting sequence variation, was performed to evaluate the mutation efficiency of the targeted site. Validating analysis confirmed the NHEJ activities was positively correlated with the mutation frequencies. Next, an approved drug library containing 1540 compounds was interrogated by using this screening strategy. Our results identified ouabain, a cardiotonic agent, and penfluridol, an antipsychotic agent, have the capacity to restrain NHEJ activity. Further experiments in vitro revealed the radiosensitizing effects of these compounds. Overall, we presented a cell-based screening for NHEJ inhibitors which could promote the discovery of novel radiosensitizers.

    更新日期:2017-09-04
  • mTOR kinase inhibition effectively decreases progression of a subset of neuroendocrine tumors that progress on rapalog therapy and delays cardiac impairment
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-01-01
    Melissa A. Orr-Asman, Zhengtao Chu, Min Jiang, Mariah Worley, Kathleen LaSance, Sheryl E Koch, Vinicius S. Carreira, Hanan M. Dahche, David R. Plas, Kakajan Komurov, Xiaoyang Qi, Carol A Mercer, Lowell B. Anthony, Jack Rubinstein, Hala Elnakat Thomas

    Inhibition of mTOR signaling using the rapalog everolimus is an FDA-approved targeted therapy for patients with lung and gastroenteropancreatic neuroendocrine tumors (NETs). However, patients eventually progress on treatment, highlighting the need for additional therapies. We focused on pancreatic NETs (pNETs) and reasoned that treatment of these tumors upon progression on rapalog therapy, with an mTOR kinase inhibitor (mTORKi) such as CC-223 could overcome a number of resistance mechanisms in tumors and delay cardiac carcinoid disease. We performed preclinical studies using human pNET cells in vitro and injected them subcutaneously or orthotopically to determine tumor progression and cardiac function in mice treated with either rapamycin alone or switched to CC-223 upon progression. Detailed signaling and RNA sequencing analyses were performed on tumors that were sensitive or progressed on mTOR treatment. Approximately 57% of mice bearing pNET tumors which progressed on rapalog therapy showed a significant decrease in tumor volume upon a switch to CC-223. Moreover, mice treated with an mTORKi exhibited decreased cardiac dilation and thickening of heart valves than those treated with placebo or rapamycin alone. In conclusion, in the majority of pNETs that progress on rapalogs, it is possible to reduce disease progression using an mTORKi, such as CC-223. Moreover, CC-223 had an additional transient cardiac benefit on valvular fibrosis compared to placebo- or rapalog-treated mice. These results provide the preclinical rationale to further develop mTORKi clinically upon progression on rapalog therapy and to further test their long term cardioprotective benefit in those NET patients prone to carcinoid syndrome.

    更新日期:2017-09-04
  • Inhibition of discoidin domain receptor 1 reduces collagen-mediated tumorigenicity in pancreatic ductal adenocarcinoma
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-01-01
    Kristina Y Aguilera, Huocong Huang, Wenting Du, Moriah M Hagopian, Zhen Wang, Stefan Hinz, Tae Hyun Hwang, Huamin Wang, Jason B. Fleming, Diego H Castrillon, Xiaomei Ren, Ke Ding, Rolf A Brekken

    The extracellular matrix (ECM), a principal component of pancreatic ductal adenocarcinoma (PDA), is rich in fibrillar collagens that facilitate tumor cell survival and chemoresistance. Discoidin domain receptor 1 (DDR1) is a receptor tyrosine kinase that specifically binds fibrillar collagens and has been implicated in promoting cell proliferation, migration, adhesion, ECM remodeling, and response to growth factors. We found that collagen-induced activation of DDR1 stimulated pro-tumorigenic signaling through protein tyrosine kinase 2 (PYK2) and pseudopodium-enriched atypical kinase 1 (PEAK1) in pancreatic cancer cells. Pharmacologic inhibition of DDR1 with an ATP competitive orally available small molecule kinase inhibitor (7rh) abrogated collagen-induced DDR1 signaling in pancreatic tumor cells and consequently reduced colony formation and migration. Furthermore, the inhibition of DDR1 with 7rh showed striking efficacy in combination with chemotherapy in orthotopic xenografts and autochthonous pancreatic tumors where it significantly reduced DDR1 activation and downstream signaling, reduced primary tumor burden, and improved chemoresponse. These data demonstrate that targeting collagen-signaling in conjunction with conventional cytotoxic chemotherapy has the potential to improve outcome for pancreatic cancer patients.

    更新日期:2017-09-04
  • Dual inhibition of Hedgehog and c-Met pathways for pancreatic cancer treatment
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-01-01
    Agnieszka A Rucki, Qian Xiao, Stephen Muth, Jianlin Chen, Xu Che, Jennifer Kleponis, Rajni Sharma, Robert A. Anders, Elizabeth M. Jaffee, Lei Zheng

    Pancreatic adenocarcinoma (PDA) is one of the most chemotherapy and radiotherapy resistant tumors. The c-Met and Hedgehog (Hh) pathways have been shown previously by our group to be key regulatory pathways in the primary tumor growth and metastases formation. Targeting both the HGF/c-Met and Hh pathways has shown promising results in pre-clinical studies; however, the benefits were not readily translated into to clinical trials with PDA patients. In this study, utilizing mouse models of PDA, we showed that inhibition of either HGF/c-Met or Hh pathways sensitize the PDA tumors to gemcitabine resulting in decreased primary tumor volume as well as significant reduction of metastatic tumor burden. However, prolonged treatment of single HGF/c-Met or Hh inhibitor leads to the resistance to these single inhibitors, likely because the single c-Met treatment leads to the enhanced expression of Shh, and vice versa. Targeting both the HGF/c-Met and Hh pathways simultaneously overcame the resistance to the single inhibitor treatment and led to a more potent anti-tumor effect in combination with the chemotherapy treatment.

    更新日期:2017-09-04
  • Trp53 Mutants Drive Neuroendocrine Lung Cancer through Loss-of-Function Mechanisms with Gain-of-Function Effects on Chemotherapy Response
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-01-01
    Nagako Akeno, Alisa L. Reece, Melissa Callahan, Ashley L. Miller, Rebecca G. Kim, Diana He, Adam Lane, Jonathan S. Moulton, Kathryn A. Wikenheiser-Brokamp

    Lung cancer is the leading cause of cancer deaths with small cell lung cancer (SCLC) as the most aggressive subtype. Preferential occurrence of TP53 missense mutations rather than loss implicates a selective advantage for TP53 mutant expression in SCLC pathogenesis. We show that lung epithelial expression of R270H and R172H (R273H and R175H in humans), common Trp53 mutations in lung cancer, combined with Rb1 loss selectively results in two subtypes of neuroendocrine carcinoma, SCLC and large cell neuroendocrine carcinoma (LCNEC). Tumor initiation and progression occur in a remarkably consistent time frame with short latency and uniform progression to lethal metastatic disease by 7 months. R270H or R172H expression and Trp53 loss result in similar phenotypes demonstrating that Trp53 mutants promote lung carcinogenesis through loss-of-function and not gain-of-function mechanisms. Tumor responses to targeted and cytotoxic therapeutics were discordant in mice and corresponding tumor cell cultures demonstrating need to assess therapeutic response at the organismal level. Rapamycin did not have therapeutic efficacy in the mouse model despite inhibiting mTOR signaling and markedly suppressing tumor cell growth in culture. In contrast, cisplatin/etoposide treatment using a patient regimen prolonged survival with development of chemoresistance recapitulating human responses. R270H, but not R172H, expression conferred gain-of-function activity in attenuating chemotherapeutic efficacy. These data demonstrate a causative role for Trp53 mutants in development of chemoresistant lung cancer, and provide tractable preclinical models to test novel therapeutics for refractory disease.

    更新日期:2017-08-29
  • Synthetic lethality interaction between Aurora kinases and CHEK1 inhibitors in ovarian cancer
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-01-01
    Ana Alcaraz-Sanabria, Cristina Nieto-Jiménez, Verónica Corrales-Sánchez, Leticia Serrano-Oviedo, Fernando Andrés-Pretel, Juan Carlos Montero, Miguel Burgos, Juan Llopis, Eva María Galán-Moya, Atanasio Pandiella, Alberto Ocaña

    Ovarian cancer is characterized by frequent mutations at TP53. These tumors also harbor germline mutations at homologous recombination repair (HR) genes, so they rely on DNA-damage checkpoint proteins, like the Checkpoint kinase 1 (CHEK1) to induce G2 arrest. In our study, by using an in silico approach, we identified a synthetic lethality interaction between CHEK1 and mitotic Aurora Kinase A (AURKA) inhibitors.  Gene expression analyses were used for the identification of relevant biological functions. OVCAR3, OVCAR8, IGROV1 and SKOV3 were used for proliferation studies. Alisertib was tested as AURKA inhibitor and LY2603618 as CHEK1 inhibitor.  Analyses of cell cycle and intracellular mediators were performed by flow cytometry and Western blot. Impact on stem cell properties was evaluated by flow cytometry analysis of surface markers  and sphere formation assays. Gene expression analyses followed by functional annotation identified a series of deregulated genes which belonged to cell cycle, including AURKA/B, TTK kinase and CHEK1.  AURKA and CHEK1 were amplified in 8.7% and 3.9% of ovarian cancers, respectively. AURKA and CHEK1 inhibitors showed a synergistic interaction in different cellular models.  Combination of Alisertib and LY2603618 triggered apoptosis, reduced the stem cell population and increased the effect of taxanes and platinum compounds. Finally, expression of AURKA and CHEK1 was linked with detrimental outcome in patients. Our data describes a synthetic lethality interaction between CHEK1 and AURKA inhibitors with potential translation to the clinical setting.

    更新日期:2017-08-29
  • Oncolytic Reactivation of KSHV as a Therapeutic Approach for Primary Effusion Lymphoma
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-01-01
    Feng Zhou, Michiko Shimoda, Laura Olney, Yuanzhi Lyu, Khiem Tran, Guochun Jiang, Kazushi Nakano, Ryan R. Davis, Clifford G. Tepper, Emanual Maverakis, Mel Campbell, Yuanpei Li, Satya Dandekar, Yoshihiro Izumiya

    Primary effusion lymphoma (PEL) is an aggressive subtype of non-Hodgkin lymphoma caused by Kaposi's sarcoma-associated herpesvirus (KSHV) infection. Currently treatment options for patients with PEL are limited. Oncolytic viruses have been engineered as anti-cancer agents and have recently shown increased therapeutic promise. Similarly, lytic activation of endogenous viruses from latently infected tumor cells can also be applied as a cancer therapy. In theory, such a therapeutic strategy would induce oncolysis by viral replication, while simultaneously stimulating an immune response to viral lytic cycle antigens. We examined the combination of the FDA-approved drug PEP005 (ingenol-3-angelate) with epigenetic drugs as a rational therapeutic approach for KSHV-mediated malignancies. JQ1, a bromodomain and extra terminal protein (BET) inhibitor, in combination with PEP005, not only robustly induced KSHV lytic replication, but also inhibited IL-6 production from PEL cells. Using the dosages of these agents that was found to be effective in reactivating HIV (as a means to clear latent virus with HAART therapy), we were able to inhibit PEL growth in vitro and delay tumor growth in a PEL xenograft tumor model. KSHV reactivation was mediated by activation of NF-κB pathway by PEP005, which led to increased occupancy of RNA polymerase II onto the KSHV genome. RNA-sequencing analysis further revealed cellular targets of PEP005, JQ1, and the synergistic effects of both. Thus, combination of PEP005 with a BET inhibitor may be considered as a rational therapeutic approach for the treatment of PEL.

    更新日期:2017-08-29
  • Lack of constitutively active DNA repair sensitizes glioblastomas to Akt inhibition and induces synthetic lethality with radiation treatment in a p53-dependentmanner
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-01-01
    Kamalakannan Palanichamy, Disha Patel, John R. Jacob, Kevin T. Litzenberg, Nicolaus Gordon, Kirstin Acus, Shin-ei Noda, Arnab Chakravarti

    Treatment refractory glioblastoma (GBM) remains a major clinical problem globally and targeted therapies in GBM have not been promising to date. TCGA integrative analysis of GBM reported the striking finding of genetic alterations in the p53 and PI3K pathways in over 80% of GBMs. Given the role of these pathways in making cell-fate decisions and responding to genotoxic stress, we investigated the reliance of these two pathways in mediating radiation-resistance. We selected a panel of GBM cell lines and glioma stem cells (GSC) with wild-type TP53 (p53-wt) and mutant TP53, mutations known to interfere with p53 functionality (p53-mt). Cell lines were treated with a brain permeable inhibitor of P-Akt (ser473), phosphatidylinositol ether lipid analogue (PIA), with and without radiation treatment. Sensitivity to treatment was measured using Annexin-V/PI flow cytometry and western blot analysis for the markers of apoptotic signaling, alkaline COMET assay. All results were verified in p53 isogenic cell lines. p53-mt cell lines were selectively radiosensitized by PIA. This radiosensitization effect corresponded with an increase in DNA damage and a decrease in DNA-PKcs levels. TP53 silencing in p53-wt cells showed a similar response as the p53-mt cells. Additionally, the radiosensitization effects of Akt inhibition were not observed in normal human astrocytes suggesting this treatment strategy could have limited off-target effects. We demonstrate that the inhibition of the PI3K/Akt pathway by PIA radiosensitizes p53-mt cells by antagonizing DNA repair. In principle, this strategy could provide a large therapeutic window for the treatment of TP53 mutant tumors.

    更新日期:2017-08-25
  • T790M-selective EGFR-TKI combined with dasatinib as an optimal strategy for overcoming EGFR-TKI resistance in T790M-positive non-small cell lung cancer
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-01-01
    Satomi Watanabe, Takeshi Yoshida, Hisato Kawakami, Naoki Takegawa, Junko Tanizaki, Hidetoshi Hayashi, Masayuki Takeda, Kimio Yonesaka, Junji Tsurutani, Kazuhiko Nakagawa

    T790M mutation-selective epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) have demonstrated clinical benefits in non-small cell lung cancer (NSCLC) patients harboring T790M mutation, which is the major cause of resistance to EGFR-TKI. However, their efficacy is limited, possibly due to the emergence of apoptosis resistance in T790M-positive NSCLC. We previously identified Src family kinases as co-oncogenic drivers along with T790M and found that the Src inhibitor dasatinib combined with an irreversible or a preclinical T790M-selective EGFR-TKI enhanced anti-tumor activity in T790M-positive cells. In the current study, we evaluated the efficacy of dasatinib combined with the clinically relevant T790M-selective EGFR-TKI or osimertinib in EGFR mutation-positive NSCLC with or without T790M mutation. A cell viability assay revealed that dasatinib had synergistic effects with these TKIs in T790M-positive cells, and simultaneously inhibited Src, Akt, and Erk, which remained activated upon single-agent treatment. Dasatinib also increased the rate of apoptosis in T790M-positive cells induced by T790M-selective EGFR-TKIs, as determined by the annexin-V binding assay; this was associated with downregulation of the anti-apoptotic Bcl-2 family member Bcl-xL, a finding that was confirmed in mice bearing T790M-positive xenografts. Our results suggest that Bcl-xL plays a key role in the apoptosis resistance of T790M-positive NSCLC, and that dasatinib combined with clinically relevant T790M-selective EGFR-TKIs is potentially effective in overcoming resistance to first-generation EGFR-TKIs in NSCLC patients with acquired T790M.

    更新日期:2017-08-25
  • Animacroxam, a novel dual-mode compound targeting histone deacetylases and cytoskeletal integrity of testicular germ cell cancer cells
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-01-01
    Gustav Steinemann, Alexandra Dittmer, Weronika Kuzyniak, Björn Hoffmann, Mark Schrader, Rainer Schobert, Bernhard Biersack, Bianca Nitzsche, Michael Hoepfner

    Novel approaches for the medical treatment of advanced solid tumors including testicular germ cell tumors (TGCT) are desperately needed. Especially, TGCT patients not responding to cisplatin-based therapy need therapeutic alternatives, as there is no effective medical treatment available for this particular subgroup. Here, we studied the suitability of the novel dual mode compound animacroxam for TGCT treatment. Animacroxam consists of a HDAC-inhibitory hydroxamate moiety coupled to a 4,5-diarylimidazole with inherent cytoskeleton disrupting potency. Animacroxam revealed pronounced antiproliferative, cell cycle arresting, and apoptosis inducing effects in TGCT cell lines with different cisplatin sensitivities. The IC50 values of animacroxam ranged from 0.22 to 0.42 µM and were not correlated to the cisplatin sensitivity of the tumor cells. No unspecific cytotoxicity of animacroxam was observed in either cisplatin sensitive or resistant TGCT cells - even at doses as high as 10 µM. Furthermore, animacroxam induced the formation of actin stress fibers in cancer cells thereby confirming the cytoskeleton disrupting and antimigratory properties of its imidazole moiety. When compared with the clinically established HDAC-inhibitor vorinostat, the novel dual mode compound animacroxam exhibited superior antitumoral efficacy in vitro. Animacroxam also reduced the tumor size of TGCT tumors in vivo, as evidenced by performing xenograft experiments on tumor bearing chorio-allantoic membranes of fertilizes chicken eggs (CAM assay). The in vivo experiments also revealed a very good tolerability of the compound and hence, aniamcroxam may be a promising candidate for innovative treatment of TGCT in general and the more so for platinum-insensitive or -refractory TGCT.

    更新日期:2017-08-25
  • The selective Tie2 inhibitor rebastinib blocks recruitment and function of Tie2Hi macrophages in breast cancer and pancreatic neuroendocrine tumors.
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-01-01
    Allison S Harney, George S. Karagiannis, Jeanine Pignatelli, Bryan D. Smith, Ece Kadioglu, Scott C. Wise, Molly M. Hood, Michael D. Kaufman, Cynthia B. Leary, Wei-Ping Lu, Gada Al-Ani, Xiaoming Chen, David Entenberg, Maja H. Oktay, Yarong Wang, Lawrence Chun, Michele De Palma, Joan G. Jones, Daniel L. Flynn, John S. Condeelis

    Tumor-infiltrating myeloid cells promote tumor progression by mediating angiogenesis, tumor cell intravasation and metastasis, which can offset the effects of chemotherapy, radiation, and anti-angiogenic therapy. Here, we show that the kinase switch control inhibitor rebastinib inhibits Tie2, a tyrosine kinase receptor expressed on endothelial cells and pro-tumoral Tie2-expressing macrophages in mouse models of metastatic cancer. Rebastinib reduces tumor growth and metastasis in an orthotopic mouse model of metastatic mammary carcinoma through reduction of Tie2+ myeloid cell infiltration, anti-angiogenic effects, and blockade of tumor cell intravasation mediated by perivascular Tie2Hi/Vegf-AHi macrophages in the tumor microenvironment of metastasis (TMEM). The anti-tumor effects of rebastinib enhance the efficacy of microtubule inhibiting chemotherapeutic agents, either eribulin or paclitaxel, by reducing tumor volume, metastasis, and improving overall survival. Rebastinib inhibition of angiopoietin/Tie2 signaling impairs multiple pathways in tumor progression mediated by pro-tumoral Tie2+ macrophages, including TMEM-dependent dissemination and angiopoietin/Tie2-dependent angiogenesis. Rebastinib is a promising therapy for achieving Tie2 inhibition in cancer patients.

    更新日期:2017-08-25
  • The Neddylation Inhibitor Pevonedistat (MLN4924) Suppresses and Radiosensitizes Head and Neck Squamous Carcinoma Cells and Tumors
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-01-01
    Vanessa Vanderdys, Amir Allak, Fadila Guessous, Mouadh Benamar, Paul W. Read, Mark J. Jameson, Tarek Abbas

    The cullin RING E3 ubiquitin ligase 4 (CRL4) with its substrate receptor CDT2 (CRL4-CDT2) is emerging as a critical regulator of DNA replication through targeting CDT1, SET8 and p21 for ubiquitin-dependent proteolysis. The aberrant increased stability of these proteins in cells with inactivated CRL4-CDT2 results in DNA rereplication, which is deleterious to cells due to the accumulation of replication intermediates and stalled replication forks. Here, we demonstrate that CDT2 is overexpressed in head and neck squamous cell carcinoma (HNSCC) and its depletion by siRNA inhibits the proliferation of human papilloma virus negative (HPV-ve) HNSCC cells primarily through the induction of rereplication. Treatment of HNSCC with the NEDD8-activating enzyme (NAE) inhibitor pevonedistat (MLN4924), which inhibits all cullin-based ligases, induces significant rereplication and inhibits HNSCC cell proliferation in culture and HNSCC xenografts in mice. Pevonedistat additionally sensitizes HNSCC cells to ionizing radiation (IR) and enhances IR-induced suppression of xenografts in mice. Induction of rereplication via CDT2 depletion, or via the stabilization or activation of CDT1, also radiosensitizes HNSCC cells. Collectively, these results demonstrate that induction of rereplication represents a novel approach to treating radioresistant HNSCC tumors and suggest that pevonedistat may be considered as an adjuvant for IR-based treatments.

    更新日期:2017-08-25
  • Radiosensitisation in vivo by histone deacetylase inhibition with no increase in early normal tissue radiation toxicity
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-01-01
    Blaz Groselj, Jia-Ling Ruan, Helen Scott, Jessica Gorrill, Judith Nicholson, Jacqueline Kelly, Selvakumar Anbalagan, James Thompson, Michael RL Stratford, Sarah J. Jevons, Ester M. Hammond, Cheryl L. Scudamore, Martin Kerr, Anne E. Kiltie

    As the population ages, more elderly patients require radiotherapy-based treatment for their pelvic malignancies, including muscle-invasive bladder cancer, as they are unfit for major surgery. Therefore, there is an urgent need to find radiosensitising agents minimally toxic to normal tissues, including bowel and bladder, for such patients. We developed methods to determine normal tissue toxicity severity in intestine and bladder in vivo , using novel radiotherapy techniques on a small animal radiation research platform (SARRP). The effects of panobinostat (PAN) on in vivo tumour growth delay were evaluated using subcutaneous xenografts in athymic nude mice. PAN concentration levels in xenografts, plasma and normal tissues were measured in CD1-nude mice. CD1-nude mice were treated with drug/irradiation combinations to assess acute normal tissue effects in small intestine using the intestinal crypt assay, and later effects in small and large intestine at 11 weeks by stool assessment and at 12 weeks by histological examination. In vitro effects of PAN were assessed by qPCR and of PAN, TMP195 and mocetinostat by clonogenic assay, and western blot. PAN resulted in growth delay in RT112 bladder cancer xenografts but did not significantly increase acute (3.75 days) or 12 weeks' normal tissue radiation toxicity. Radiosensitisation by PAN was effective in hypoxic bladder cancer cells and associated with class I HDAC inhibition, and protein downregulation of HDAC2 and MRE11. Pan-HDAC inhibition is a promising strategy for radiosensitisation, but more selective agents may be more useful radiosensitisers clinically, resulting in fewer systemic side effects.

    更新日期:2017-08-25
  • Tumor Mutational Burden as an Independent Predictor of Response to Immunotherapy in Diverse Cancers
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-01-01
    Aaron M. Goodman, Shumei Kato, Lyudmila Bazhenova, Sandip P. Patel, Garrett M. Frampton, Vincent Miller, Philip J. Stephens, Gregory A Daniels, Razelle Kurzrock

    Immunotherapy induces durable responses in a subset of patients with cancer. High TMB may be a response biomarker for PD-1/PD-L1 blockade in tumors such as melanoma and non-small cell lung cancer (NSCLC). Our aim was to examine the relationship between TMB and outcome in diverse cancers treated with various immunotherapies. We reviewed data on 1,638 patients who had undergone comprehensive genomic profiling and had TMB assessment. Immunotherapy-treated patients (N = 151) were analyzed for response rate (RR), progression-free and overall survival (PFS, OS). Higher TMB was independently associated with better outcome parameters (multivariable analysis). The RR for patients with high (≥ 20 mutations/mb) vs. low to intermediate TMB was 22/38 (58%) vs. 23/113 (20%) (P = 0.0001); median PFS, 12.8 vs. 3.3 months (P = <0.0001); median OS, not reached vs. 16.3 months (P = 0.0036) (Table). Results were similar when anti-PD-1/PD-L1 monotherapy was analyzed (N = 102 patients), with a linear correlation between higher TMB and favorable outcome parameters; the median TMB for responders vs. non-responders treated with anti-PD-1/PD-L1 monotherapy was 18.0 vs. 5.0 mutations/mb (P < 0.0001). Interestingly, anti-CTLA4/anti-PD-1/PD-L1 combinations vs. anti-PD-1/PD-L1 monotherapy was selected as a factor independent of TMB for predicting better RR (77% vs. 21%) (P = 0.004) and PFS (P = 0.024). Higher TMB predicts favorable outcome to PD-1/PD-L1 blockade across diverse tumors. Benefit from dual checkpoint blockade did not show a similarly strong dependence on TMB.

    更新日期:2017-08-24
  • Targeting phosphatidylinositol 3-kinase signaling pathway for therapeutic enhancement of vascular-targeted photodynamic therapy
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-01-01
    Daniel Kraus, Pratheeba Palasuberniam, Bin Chen

    Vascular-targeted photodynamic therapy (PDT) selectively disrupts vascular function by inducing oxidative damages to the vasculature, particularly endothelial cells. Although effective tumor eradication and excellent safety profile are well demonstrated in both preclinical and clinical studies, incomplete vascular shutdown and angiogenesis are known to cause tumor recurrence after vascular-targeted PDT. We have explored therapeutic enhancement of vascular-targeted PDT with phosphatidylinositol 3-kinase (PI3K) signaling pathway inhibitors because the activation of PI3K pathway was involved in promoting endothelial cell survival and proliferation after PDT. Here three clinically relevant small molecule inhibitors (BYL719, BKM120 and BEZ235) of the PI3K pathway were evaluated in combination with verteporfin-PDT. Although all three inhibitors were able to synergistically enhance PDT response in endothelial cells, PDT combined with dual PI3K/mTOR inhibitor BEZ235 exhibited the strongest synergism, followed in order by combinations with pan-PI3K inhibitor BKM120 and p110α isoform-selective inhibitor BYL719. Combination treatments of PDT and BEZ235 exhibited a cooperative inhibition of anti-apoptotic Bcl-2 family protein Mcl-1 and induced more cell apoptosis than each treatment alone. In addition to increasing treatment lethality, BEZ235 combined with PDT effectively inhibited PI3K pathway activation and consequent endothelial cell proliferation after PDT alone, leading to a sustained growth inhibition. In the PC-3 prostate tumor model, combination treatments improved treatment outcomes by turning a temporary tumor regrowth delay induced by PDT alone to a more long-lasting treatment response. Our study strongly supports the combination of vascular-targeted PDT and PI3K pathway inhibitors, particularly mTOR inhibitors, for therapeutic enhancement.

    更新日期:2017-08-24
  • Estrogen receptor {beta} is a novel target in acute myeloid leukemia
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-01-01
    Sarah-Grace Rota, Alessia Roma, Iulia Dude, Christina Ma, Robert Stevens, Janet MacEachern, Joanna Graczyk, Shaundrei Mabriel G Espiritu, Praveen N. Rao, Mark D Minden, Elena Kreinin, David A. Hess, Andrew C Doxey, Paul A Spagnuolo

    Acute myeloid leukemia (AML) is a devastating disease characterized by poor patient outcome and suboptimal chemotherapeutics. Here, a high throughput screen identified diosmetin, a citrus flavonoid, with anti-AML activity. Diosmetin imparted selective toxicity against leukemia and leukemia stem cells in vitro and in vivo with no effect on normal hematopoietic stem cells. Mechanistically, we demonstrated that diosmetin targets estrogen receptor (ER) β. ERβ expression conferred cell sensitivity, as patient-derived AML cells with high levels of ERβ were sensitive whereas cells with low ERβ were insensitive to diosmetin. Knockdown of ERβ confirmed resistance whereas overexpression enhanced sensitivity to diosmetin; which was demonstrated to be mediated by ROS signaling.  In summary, these studies highlight targeting of ERβ with diosmetin as a potential novel therapeutic strategy for the treatment of AML.

    更新日期:2017-08-24
  • EZH2 inhibition by tazemetostat results in altered dependency on B-cell activation signaling in DLBCL
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-01-01
    Dorothy Brach, Danielle Johnston-Blackwell, Allison Drew, Trupti Lingaraj, Vinny Motwani, Natalie M. Warholic, Igor Feldman, Christopher Plescia, Jesse J. Smith, Robert A. Copeland, Heike Keilhack, Elayne Chan-Penebre, Sarah K. Knutson, Scott A Ribich, Alejandra Raimondi, Michael J. Thomenius

    The EZH2 small molecule inhibitor tazemetostat (EPZ-6438) is currently being evaluated in phase II clinical trials for the treatment of non-Hodgkin's Lymphoma (NHL).  We have previously shown that EZH2 inhibitors display an anti-proliferative effect in multiple pre-clinical models of NHL, and that models bearing gain-of-function mutations in EZH2 were consistently more sensitive to EZH2 inhibition than lymphomas with wild-type (WT) EZH2 . Here, we demonstrate that cell lines bearing EZH2 mutations show a cytotoxic response, while cell lines with WT- EZH2 show a cytostatic response and only tumor growth inhibition without regression in a xenograft model.  Previous work has demonstrated that co-treatment with tazemetostat and glucocorticoid receptor agonists lead to a synergistic anti-proliferative effect in both mutant and wild-type backgrounds, which may provide clues to the mechanism of action of EZH2 inhibition in WT- EZH2 models.  Multiple agents that inhibit the B-cell receptor pathway (e.g. ibrutinib) were found to have synergistic benefit when combined with tazemetostat in both mutant and WT- EZH2 backgrounds of diffuse large B-Cell Lymphomas (DLBCL). The relationship between B-cell activation and EZH2 inhibition is consistent with the proposed role of EZH2 in B-cell maturation.  To further support this, we observe that cell lines treated with tazemetostat show an increase in the B-cell maturation regulator, PRDM1 /BLIMP1 and gene signatures corresponding to more advanced stages of maturation.  These findings suggest that EZH2 inhibition in both mutant and wild-type backgrounds leads to increased B-cell maturation and a greater dependence on B-cell activation signaling.

    更新日期:2017-08-24
  • Characterization of in vivo resistance to osimertinib and JNJ-61186372, an EGFR/Met bi-specific antibody, reveals unique and consensus mechanisms of resistance
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-01-01
    Kristina B. Emdal, Antje Dittmann, Raven J. Reddy, Rebecca S. Lescarbeau, Sheri L. Moores, Sylvie Laquerre, Forest M. White

    Approximately 10% of non-small cell lung cancer (NSCLC) patients in the U.S. and 40% of NSCLC patients in Asia have activating EGFR mutations and are eligible to receive targeted anti-EGFR therapy. Despite an extension of life expectancy associated with this treatment, resistance to EGFR tyrosine kinase inhibitors and anti-EGFR antibodies is almost inevitable. To identify additional signaling routes that can be co-targeted to overcome resistance, we quantified tumor-specific molecular changes that govern resistant cancer cell growth and survival. Mass spectrometry-based quantitative proteomics was used to profile in vivo signaling changes in 41 therapy resistant tumors from four xenograft NSCLC models. We identified unique and tumor-specific tyrosine phosphorylation rewiring in tumors resistant to treatment with the irreversible third generation EGFR-inhibitor, osimertinib, or the novel dual-targeting EGFR/Met antibody, JNJ-61186372. Tumor-specific increases in tyrosine-phosphorylated peptides from EGFR family members, Shc1 and Gab1 or Src family kinase substrates were observed, underscoring a differential ability of tumors to uniquely escape EGFR inhibition. Although most resistant tumors within each treatment group displayed a marked inhibition of EGFR as well as Src family kinase (SFK) signaling, the combination of EGFR inhibition (osimertinib) and SFK inhibition (saracatinib or dasatinib) led to further decrease in cell growth in vitro. This result suggests that residual SFK signaling mediates therapeutic resistance and that elimination of this signal through combination therapy may delay onset of resistance. Overall, analysis of individual resistant tumors captured unique in vivo signaling rewiring that would have been masked by analysis of in vitro cell population averages.

    更新日期:2017-08-23
  • Inhibition of Aurora A and Aurora B Is Required for the Sensitivity of HPV-Driven Cervical Cancers to Aurora Kinase Inhibitors
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-05-18
    David Martin, Sora Fallaha, Martina Proctor, Alexander Stevenson, Lewis Perrin, Nigel McMillan, Brian Gabrielli

    The activity and efficacy of Aurora inhibitors have been reported in a wide range of cancer types. The most prominent Aurora inhibitor is alisertib, an investigational Aurora inhibitor that has been the subject of more than 30 clinical trials. Alisertib has inhibitory activity against both Aurora A and B, although it is considered to be primarily an Aurora A inhibitor in vivo . Here, we show that alisertib inhibits both Aurora A and B in vivo in preclinical models of HPV-driven cervical cancer, and that it is the inhibition of Aurora A and B that provides the selectivity and efficacy of this drug in vivo in this disease setting. We also present formal evidence that alisertib requires progression through mitosis for its efficacy, and that it is unlikely to combine with drugs that promote a G2 DNA damage checkpoint response. This work demonstrates that inhibition of Aurora A and B is required for effective control of HPV-driven cancers by Aurora kinase inhibitors. Mol Cancer Ther; 16(9); 1–8. ©2017 AACR.

    更新日期:2017-08-23
  • Targeting TAO kinases using a new inhibitor compound delays mitosis and induces mitotic cell death in centrosome amplified breast cancer cells.
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-01-01
    Chuay-Yeng Koo, Caterina Giacomini, Marta Reyes-Corral, Yolanda Olmos, Ignatius A. Tavares, Charles M. Marson, Spiros Linardopoulos, Andrew N. Tutt, Jonathan D.H. Morris

    Thousand-and-one amino acid kinases (TAOKs) 1 and 2 are activated catalytically during mitosis and can contribute to mitotic cell rounding and spindle positioning. Here, we characterize a compound that inhibits TAOK1 and TAOK2 activity with IC50 values of 11-15 nM, is ATP-competitive and targets these kinases selectively. TAOK inhibition or depletion in centrosome amplified SKBR3 or BT549 breast cancer cell models increases the mitotic population, the percentages of mitotic cells displaying amplified centrosomes and multipolar spindles, induces cell death and inhibits cell growth. In contrast, non-tumorigenic and dividing bipolar MCF-10A breast cells appear less dependent on TAOK activity and can complete mitosis and proliferate in the presence of the TAOK inhibitor. We demonstrate that TAOK1 and TAOK2 localize to the cytoplasm and centrosomes respectively during mitosis. Live cell imaging shows that the TAOK inhibitor prolongs the duration of mitosis in SKBR3 cells, increases mitotic cell death and reduces the percentages of cells exiting mitosis, whereas MCF-10A cells continue to divide and proliferate. Over 80% of breast cancer tissues display supernumerary centrosomes and tumor cells frequently cluster extra centrosomes to avoid multipolar mitoses and associated cell death. Consequently, drugs that stimulate centrosome declustering and induce multipolarity are likely to target dividing centrosome amplified cancer cells preferentially, whilst sparing normal bipolar cells. Our results demonstrate that TAOK inhibition can enhance centrosome declustering and mitotic catastrophe in cancer cells and these proteins may therefore offer novel therapeutic targets suitable for drug inhibition and the potential treatment of breast cancers, where supernumerary centrosomes occur.

    更新日期:2017-08-23
  • IL-6 receptor blockade enhances chemotherapy efficacy in pancreatic ductal adenocarcinoma
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-01-01
    Kristen B. Long, Graham Tooker, Evan Tooker, Santiago Lombo Luque, Jae W. Lee, Xiaoqing Pan, Gregory L. Beatty

    Inflammation mediated by activation of JAK/STAT signaling is a major cause of chemotherapy resistance in cancer. We studied the impact of selectively blocking the IL6 receptor (IL6R) as a strategy to inhibit IL6-induced STAT activation and to overcome chemoresistance in pancreatic ductal adenocarcinoma (PDAC). To do this, STAT activation was investigated in tumors arising spontaneously in LSL-KrasG12D/+;LSL-Trp53R172H/+;Pdx-1Cre (KPC) mice. Plasma from patients with PDAC was assessed for its ability to activate STAT3/SOCS3 in human monocytes using immunofluorescence microscopy and quantitative gene expression assays. KPC mice and syngeneic mice (wild type and IL6−/−) implanted with KPC-derived cell lines were treated with an IL6R-blocking antibody (anti-IL6R). The impact of treatment on tumor growth in KPC mice and mice with KPC-derived tumor implants was monitored using ultrasonography and calipers, respectively. Tumors were analyzed by IHC to detect changes in STAT activation, tumor viability, and proliferation. We found that STAT3 was the most activated STAT protein in PDAC tumors from KPC mice. Plasma from patients with advanced PDAC stimulated STAT3/SOCS3 activation in human monocytes. In mice, anti-IL6R antibodies targeted Ly6Chi monocytes, inhibited STAT3 activation in tumor cells, and decreased tumor cell proliferation in vivo . IL6R blockade in combination with chemotherapy induced tumor cell apoptosis, tumor regressions, and improved overall survival. Overall, we show that IL6 signaling drives STAT3 activation in tumor cells and mediates chemoresistance in PDAC. Thus, disrupting IL6 signaling using anti-IL6R antibodies holds promise for improving chemotherapy efficacy in PDAC. Mol Cancer Ther; 16(9); 1–11. ©2017 AACR.

    更新日期:2017-08-23
  • Inhibition of Hsp90 suppresses PI3K/AKT/mTOR signaling and has antitumor activity in Burkitt lymphoma
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-01-01
    Lisa Giulino-Roth, Herman J Van Besien, Tanner Dalton, Jennifer E. Totonchy, Anna Rodina, Tony Taldone, Alexander Bolaender, Hediye Erdjument-Bromage, Jouliana Sadek, Amy Chadburn, Matthew J Barth, Filemon S Dela Cruz, Allison Rainey, Andrew L Kung, Gabriela Chiosis, Ethel Cesarman

    Hsp90 is a molecular chaperone that protects proteins, including oncogenic signaling complexes, from proteolytic degradation. PU-H71 is a next-generation Hsp90 inhibitor that preferentially targets the functionally distinct pool of Hsp90 present in tumor cells. Tumors that are driven by the MYC oncoprotein may be particularly sensitive to PU-H71 due to the essential role of Hsp90 in the epichaperome, which maintains the malignant phenotype in the setting of MYC. Burkitt lymphoma (BL) is an aggressive B-cell lymphoma characterized by MYC dysregulation. In this study, we evaluated Hsp90 as a potential therapeutic target in BL. We found that primary BL tumors overexpress Hsp90 and that Hsp90 inhibition has antitumor activity in vitro and in vivo , including potent activity in a patient-derived xenograft model of BL. To evaluate the targets of PU-H71 in BL, we performed high-affinity capture followed by proteomic analysis using mass spectrometry. We found that Hsp90 inhibition targets multiple components of PI3K/AKT/mTOR signaling, highlighting the importance of this pathway in BL. Finally, we found that the anti-lymphoma activity of PU-H71 is synergistic with dual PI3K/mTOR inhibition in vitro and in vivo . Overall, this work provides support for Hsp90 as a therapeutic target in BL and suggests the potential for combination therapy with PU-H71 and inhibitors of PI3K/mTOR. Mol Cancer Ther; 16(9); 1–12. ©2017 AACR.

    更新日期:2017-08-23
  • Arginine Deprivation Therapy: Putative Strategy to Eradicate Glioblastoma Cells by Radiosensitization
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-01-01
    C. Noreen Hinrichs, Mirjam Ingargiola, Theresa Käubler, Steffen Löck, Achim Temme, Alvaro Köhn-Luque, Andreas Deutsch, Olena Vovk, Oleh Stasyk, Leoni A. Kunz-Schughart

    Tumor cells - even if non-auxotrophic - are often highly sensitive to arginine deficiency. We hypothesized that arginine deprivation therapy (ADT) if combined with irradiation could be a new treatment strategy for glioblastoma (GBM) patients since systemic ADT is independent of local penetration and diffusion limitations. A proof-of-principle in vitro study was performed with ADT been mimicked by application of recombinant human arginase or arginine-free diets. ADT inhibited 2-D growth and cell cycle progression, and reduced growth recovery after completion of treatment in four different GBM cell line models. Cells were less susceptible to ADT alone in the presence of citrulline and in a 3-D environment. Migration and 3-D invasion were not unfavourably affected. However, ADT caused a significant radiosensitization which was more pronounced in a GBM cell model with p53 loss of function as compared to its p53- wildtype counterpart. The synergistic effect was independent of basic and induced argininosuccinate synthase (ASS) or argininosuccinate lyase (ASL) protein expression and not abrogated by the presence of citrulline. The radiosensitizing potential was maintained or even more distinguishable in a 3-D environment as verified in p53-knockdown and p53-wildtype U87-MG cells via a 60-day spheroid control probability assay. While the underlying mechanism is still ambiguous, the observation of ADT-induced radiosensitization is of great clinical interest, in particular for patients with GBM showing high radioresistance and/or p53 loss of function.

    更新日期:2017-08-23
  • An in vivo functional screen identifies JNK signaling as a modulator of chemotherapeutic response in breast cancer
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-01-01
    Matthew Ashenden, Antoinette van Weverwijk, Nirupa Murugaesu, Antony Fearns, James Campbell, Qiong Gao, Marjan Iravani, Clare M. Isacke

    Chemotherapy remains the mainstay of treatment for advanced breast cancer; however, resistance is an inevitable event for the majority of patients with metastatic disease. Moreover, there is little information available to guide stratification of first-line chemotherapy, crucial given the common development of multidrug resistance. Here, we describe an in vivo screen to interrogate the response to anthracycline-based chemotherapy in a syngeneic metastatic breast cancer model and identify JNK signaling as a key modulator of chemotherapy response. Combining in vitro and in vivo functional analyses, we demonstrate that JNK inhibition both promotes tumor cell cytostasis and blocks activation of the proapoptotic protein Bax, thereby antagonizing chemotherapy-mediated cytotoxicity. To investigate the clinical relevance of this dual role of JNK signaling, we developed a proliferation-independent JNK activity signature and demonstrate high JNK activity to be enriched in triple-negative and basal-like breast cancer subtypes. Consistent with the dual role of JNK signaling in vitro , high-level JNK pathway activation in triple-negative breast cancers is associated both with poor patient outcome in the absence of chemotherapy treatment and, in neoadjuvant clinical studies, is predictive of enhanced chemotherapy response. These data highlight the potential of monitoring JNK activity as early biomarker of response to chemotherapy and emphasize the importance of rational treatment regimes, particularly when combining cytostatic and chemotherapeutic agents. Mol Cancer Ther; 16(9); 1–12. ©2017 AACR.

    更新日期:2017-08-23
  • Discovery of a Novel Small-Molecule Inhibitor that Targets PP2A-{beta}-Catenin Signaling and Restricts Tumor Growth and Metastasis
    Mol. Cancer Ther. (IF 5.764) Pub Date : 2017-05-12
    Shrankhla Maheshwari, Srinivasa R. Avula, Akhilesh Singh, L. Ravithej Singh, Gopala R. Palnati, Rakesh K. Arya, Srikanth H. Cheruvu, Sudhir Shahi, Tanuj Sharma, Sanjeev Meena, Anup K. Singh, Ruchir Kant, Mohammed Riyazuddin, Himangsu K. Bora, Mohammad I. Siddiqi, Jiaur R. Gayen, Koneni V. Sashidhara, Dipak Datta

    Molecular hybridization of different pharmacophores to tackle both tumor growth and metastasis by a single molecular entity can be very effective and unique if the hybrid product shows drug-like properties. Here, we report synthesis and discovery of a novel small-molecule inhibitor of PP2A–β-catenin signaling that limits both in vivo tumor growth and metastasis. Our molecular hybridization approach resulted in cancer cell selectivity and improved drug-like properties of the molecule. Inhibiting PP2A and β-catenin interaction by selectively engaging PR55α-binding site, our most potent small-molecule inhibitor diminished the expression of active β-catenin and its target proteins c-Myc and Cyclin D1. Furthermore, it promotes robust E-cadherin upregulation on the cell surface and increases β-catenin–E-Cadherin association, which may prevent dissemination of metastatic cells. Altogether, we report synthesis and mechanistic insight of a novel drug-like molecule to differentially target β-catenin functionality via interacting with a particular subunit of PP2A. Mol Cancer Ther; 16(9); 1–15. ©2017 AACR.

    更新日期:2017-08-23
Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
所有期刊列表A-Z