Ceramides are bioactive lipids that mediate cell death in cancer cells, and ceramide-based therapy is now being tested in dose-escalating phase I clinical trials as a cancer treatment. Multiple nanoscale delivery systems for ceramide have been proposed to overcome the inherent toxicities, poor pharmacokinetics, and difficult biophysics associated with ceramide. Using the ceramide nanoliposomes (CNL), we now investigate the therapeutic efficacy and signaling mechanisms of this nanoscale delivery platform in refractory ovarian cancer. Treatment of ovarian cancer cells with CNL decreased the number of living cells through necroptosis but not apoptosis. Mechanistically, dying SKOV3 ovarian cancer cells exhibit activation of pseudokinase mixed lineage kinase domain-like (MLKL) as evidenced by oligomerization and relocalization to the blebbing membranes, showing necroptotic characteristics. Knockdown of MLKL, but not its upstream protein kinases such as receptor-interacting protein kinases, with siRNA significantly abolished CNL-induced cell death. Monomeric MLKL protein expression inversely correlated with the IC50 values of CNL in distinct ovarian cancer cell lines, suggesting MLKL as a possible determinant for CNL-induced cell death. Finally, systemic CNL administration suppressed metastatic growth in an ovarian cancer cell xenograft model. Taken together, these results suggest that MLKL is a novel pronecroptotic target for ceramide in ovarian cancer models. Mol Cancer Ther; 17(1); 50–59. ©2017 AACR.

中文翻译：

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神经酰胺纳米脂质体作为 MLKL 依赖性、诱导坏死性凋亡的卵巢癌化疗试剂


神经酰胺是介导癌细胞死亡的生物活性脂质，基于神经酰胺的疗法目前正在剂量递增的 I 期临床试验中作为癌症治疗进行测试。已经提出了多种神经酰胺纳米级递送系统来克服与神经酰胺相关的固有毒性、较差的药代动力学和困难的生物物理学。使用神经酰胺纳米脂质体（CNL），我们现在研究这种纳米级递送平台在难治性卵巢癌中的治疗功效和信号传导机制。用 CNL 处理卵巢癌细胞会通过坏死性凋亡而不是凋亡减少活细胞数量。从机制上讲，垂死的 SKOV3 卵巢癌细胞表现出假激酶混合谱系激酶结构域样 (MLK​​L) 的激活，寡聚化和重新定位到起泡膜即可证明，显示出坏死性凋亡特征。用 siRNA 敲低 MLKL，但不能敲低其上游蛋白激酶，如受体相互作用蛋白激酶，可显着消除 CNL 诱导的细胞死亡。在不同的卵巢癌细胞系中，单体 MLKL 蛋白表达与 CNL 的 IC50 值呈负相关，表明 MLKL 可能是 CNL 诱导的细胞死亡的决定因素。最后，全身 CNL 给药抑制卵巢癌细胞异种移植模型中的转移生长。综上所述，这些结果表明 MLKL 是卵巢癌模型中神经酰胺的一种新的促凋亡靶点。摩尔癌症治疗； 17(1)； 50–59。 ©2017 AACR。