目的：探究敲减Beclin1 表达对卵巢癌细胞A2780 对顺铂耐药的影响及其相关机制。方法：以Western blotting 及qPCR 检测卵巢癌细胞株A2780 及耐药细胞株A2780/DDP 中Beclin1 的表达情况；A2780/DDP 细胞转染Beclin1 siRNA 后，用MTT法检测细胞对顺铂敏感性的变化，克隆形成实验检测各组细胞的克隆形成情况，流式细胞术检测各组细胞的凋亡，MDC荧光染色检测细胞的自噬情况，Western blotting 检测自噬相关蛋白、溶酶体相关膜蛋白Lamp-2 以及组织蛋白酶Cathepsin B的表达情况。结果：顺铂耐药细胞株A2780/DDP 中Beclin1 mRNA及蛋白的表达水平均明显高于A2780 细胞株（均P<0.05），在A2780细胞中加入顺铂刺激后Beclin1 蛋白的表达水平显著升高（P<0.05）。敲减Beclin1 表达可促进顺铂诱导的A2780/DDP 细胞的凋亡（P<0.05）、抑制细胞自噬的发生（P<0.05）、减少细胞克隆形成（P<0.05）和增加细胞对顺铂的敏感性（P<0.05）；Western blotting结果显示，敲减Beclin1 可上调A2780/DDP 细胞中cleaved-caspase 3 和Cathepsin B的蛋白水平，下调Atg3、Atg7、LC3Ⅱ/Ⅰ、Lamp-2的表达水平（均P<0.05）。结论：敲减Beclin1 表达可提高A2780/DDP细胞对顺铂的敏感性，其机制可能与调节自噬相关蛋白表达抑制细胞保护性自噬和影响溶酶体功能，从而促进顺铂诱导耐药细胞凋亡有关。

Objective: To investigate the effect of Beclin1 knockdown on cisplatin resistance in ovarian cancer A2780 cells and its related mechanisms. Methods: The mRNA and protein expressions of Beclin1 in A2780 cells and drug resistant A2780/DDP cells were determined by qPCR and Western blotting. After transfection with Beclin1 siRNA, the sensitivity of A2780/DDP cells to cisplatin was detected by MTT assay; Cell clone formation and apoptosis were detected by the Colony formation assay and Flow cytometry assay, respectively; cell autophagy was monitored by monodansylcadaverin (MDC) staining. Furthermore, the protein levels of cell autophagy related proteins, lysosomal associated membrane protein Lamp-2 and Cathepsin B were detected by Western blotting.Results: The mRNA and protein expression levels of Beclin1 in cisplatin-resistant A2780/DDP cells were significantly higher than those in A2780 cells (all P<0.05). The expression of Beclin1 was significantly increased in A2780 cells after treated with cisplatin (P<0.05). Beclin1 knockdown promoted cisplatin induced apoptosis of A2780/DDP cells (P<0.05), inhibited autophagy and cell colony formation (all P<0.05), and increased cell sensitivity to cisplatin (P<0.05). Meanwhile, Western blotting showed that Beclin1 knockdown increased the protein levels of cleaved-caspase 3 and Cathepsin B in A2780/DDP cells, while down-regulated the protein expressions of Atg3, Atg7, LC3Ⅱ/Ⅰ and Lamp-2 (all P<0.05). Conclusion: Beclin1 knockdown can improve the sensitivity of A2780/DDP cells to cisplatin, and the mechanism may be related to the inhibition of protective autophagy of cells by regulating the expressions of autophagy related proteins, and the regulation of lysosomes, thus further promoting cisplatin-induced apoptosis of drug-resistant cells.

河南省医学科技攻关计划项目(No. 201503140)