紫杉醇联合NSC23925通过抑制肿瘤细胞自噬增强卵巢癌紫杉醇敏感性及其机制研究

The development of paclitaxel resistance severely limits the success of chemotherapy and clinical outcome in ovarian cancer. Paclitaxel in combination with chemosensitizer has been considered as one of the promising strategies to overcome paclitaxel resistance. NSC23925 (a small molecular compound, http://pubchem.ncbi.nlm.nih.gov/) previously has been identified as a potent palcitaxel resistance reversal agent; however, relatively little is known about its underling molecular mechanisms. Our most recent results showed that increased paclitaxel sensitivity as well as decreased expression of autophagy-associated proteins Beclin 1, Atg5 and LC3 was exhibited in paclitaxel-NSC23925 co-treated cells as compared to paclitaxel-treated ovarian cancer cells. However, whether the combination of paclitaxel and NSC23925 initially inhibits autophagy, subsequently enhances ovarian cancer sensitivity to paclitaxel, and the detailed mechanisms remains unclear. Thus, the objectives of present study are to verify the effects of NSC23925 on the regulation of autophagy in ovarian cancer both in cultured cells and in mouse models, determine whether NSC23925 restore paclitaxel sensitivity of ovarian cancer via actively inhibiting autophagy, identify either the target genes or proteins, and further evaluate expression patterns of the identified target factor in clinical ovarian cancer samples. The current work will further elucidate the mechanisms of NSC23925 on reversing of paclitaxel resistance in ovarian cancer, and therefore promote the potential clinical application of NSC23295 to prolong survival of women with ovarian cancer.

紫杉醇耐药严重影响卵巢癌患者化疗结局和临床预后，寻找化疗增敏剂对攻克卵巢癌化疗耐药具有重要意义。申请人已报道NSC23925（小分子化合物，简称NSC）可以防治卵巢癌紫杉醇耐药，但有关其作用机制报道较少。我们最新研究发现，与紫杉醇单独处理相比，紫杉醇联合NSC处理在增强卵巢癌紫杉醇敏感性的同时，降低自噬相关蛋白Atg5、LC3等的表达。但是，上述蛋白水平的改变是卵巢癌细胞紫杉醇敏感性增强后的结果，还是NSC通过主动调节自噬水平，增强卵巢癌细胞对紫杉醇的敏感性，以及潜在的分子机制，目前还未知。因此，本项目将在卵巢癌体外培养细胞和体内裸鼠模型中探讨NSC对紫杉醇诱导的自噬的影响，验证联合应用NSC是否通过抑制自噬增强卵巢癌对紫杉醇的敏感性，揭示其抑制自噬的作用靶点，并进一步在卵巢癌临床标本中评估此靶点的表达水平和临床意义。本项目将进一步丰富NSC的作用机制研究，为其向临转化提供实验室理论基础。

紫杉醇耐药严重影响卵巢癌患者化疗结局和临床预后，寻找化疗增敏剂对攻克卵巢癌化疗耐药具有重要意义。已报道，NSC23925可以防治卵巢癌紫杉醇耐药，但有关其作用机制报道较少。本项目探讨了联合应用NSC23925对卵巢癌紫杉醇处理过程中自噬水平的影响。我们的研究结果提示紫杉醇可以诱导卵巢癌细胞高表达LC3A/B II，促进自噬。与紫杉醇单独处理相比，紫杉醇联合NSC23925处理的卵巢细胞ES-2和HeyTR高表达LC3A/B II和P62，低表达PI3K III和Beclin 1。使用自噬双标腺病毒（mRFP-GFP-LC3）、透射电子显微镜等，进一步证实，联合使用NSC2935可以抑制卵巢癌紫杉醇处理过程中的自噬流，促进细胞凋亡，从而增加卵巢癌细胞对紫杉醇的敏感性。PI3K III/beclin1通路可能参与此过程。此项目进一步丰富了NSC23925防治卵巢癌耐药的作用机制研究，为其向临床转化提供实验室理论基础。