Phosphoinositide 3-kinases (PI3Ks) are critical regulators of diverse cellular functions and have emerged as promising targets in cancer therapy. Despite significant progress, existing PI3K inhibitors encounter various challenges such as suboptimal bioavailability, potential off-target effects, restricted therapeutic indices, and cancer-acquired resistance. Hence, novel inhibitors that overcome some of these challenges are needed. Here, we describe the characterization of KTC1101, a novel pan-PI3K inhibitor that simultaneously targets tumor cell proliferation and the tumor microenvironment. Our studies demonstrate that KTC1101 significantly increases the anti-PD-1 efficacy in multiple pre-clinical mouse models. KTC1101 was synthesized and characterized employing chemical synthesis, molecular modeling, Nuclear Magnetic Resonance (NMR), and mass spectrometry. Its target specificity was confirmed through the kinase assay, JFCR39 COMPARE analysis, and RNA-Seq analysis. Metabolic stability was verified via liver microsome and plasma assays, pharmacokinetics determined by LC–MS/MS, and safety profile established through acute toxicity assays to determine the LD50. The antiproliferative effects of KTC1101 were evaluated in a panel of cancer cell lines and further validated in diverse BALB/c nude mouse xenograft, NSG mouse xenograft and syngeneic mouse models. The KTC1101 treatment effect on the immune response was assessed through comprehensive RNA-Seq, flow cytometry, and immunohistochemistry, with molecular pathways investigated via Western blot, ELISA, and qRT-PCR. KTC1101 demonstrated strong inhibition of cancer cell growth in vitro and significantly impeded tumor progression in vivo. It effectively modulated the Tumor Microenvironment (TME), characterized by increased infiltration of CD8+ T cells and innate immune cells. An intermittent dosing regimen of KTC1101 enhanced these effects. Notably, KTC1101 synergized with anti-PD-1 therapy, significantly boosting antitumor immunity and extending survival in preclinical models. KTC1101's dual mechanism of action—directly inhibiting tumor cell growth and dynamically enhancing the immune response— represents a significant advancement in cancer treatment strategies. These findings support incorporating KTC1101 into future oncologic regimens to improve the efficacy of immunotherapy combinations.

中文翻译：

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新型泛 PI3K 抑制剂 KTC1101 通过靶向肿瘤抑制和免疫激活与抗 PD-1 疗法产生协同作用

磷酸肌醇 3-激酶 (PI3K) 是多种细胞功能的关键调节因子，并已成为癌症治疗中有希望的靶标。尽管取得了重大进展，现有的 PI3K 抑制剂仍面临各种挑战，例如生物利用度欠佳、潜在的脱靶效应、治疗指数受限和癌症获得性耐药。因此，需要克服其中一些挑战的新型抑制剂。在这里，我们描述了 KTC1101 的特性，这是一种新型泛 PI3K 抑制剂，可同时靶向肿瘤细胞增殖和肿瘤微环境。我们的研究表明，KTC1101 在多种临床前小鼠模型中显着提高了抗 PD-1 功效。KTC1101 采用化学合成、分子建模、核磁共振 (NMR) 和质谱法进行合成和表征。其靶标特异性通过激酶测定、JFCR39 COMPARE 分析和 RNA-Seq 分析得到证实。通过肝微粒体和血浆测定验证代谢稳定性，通过 LC-MS/MS 测定药代动力学，并通过急性毒性测定确定 LD50 建立安全性概况。KTC1101 的抗增殖作用在一组癌细胞系中进行了评估，并在不同的 BALB/c 裸鼠异种移植物、NSG 小鼠异种移植物和同基因小鼠模型中得到了进一步验证。通过综合 RNA-Seq、流式细胞术和免疫组织化学评估 KTC1101 治疗对免疫反应的影响，并通过蛋白质印迹、ELISA 和 qRT-PCR 研究分子途径。KTC1101 在体外表现出对癌细胞生长的强烈抑制作用，并在体内显着阻碍肿瘤的进展。它有效调节肿瘤微环境 (TME)，其特点是增加 CD8+ T 细胞和先天免疫细胞的浸润。KTC1101 的间歇给药方案增强了这些效果。值得注意的是，KTC1101 与抗 PD-1 疗法具有协同作用，显着增强抗肿瘤免疫力并延长临床前模型的生存期。KTC1101 的双重作用机制——直接抑制肿瘤细胞生长和动态增强免疫反应——代表了癌症治疗策略的重大进步。这些发现支持将 KTC1101 纳入未来的肿瘤治疗方案中，以提高免疫治疗组合的疗效。