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目的 探讨动力相关蛋白1(dynamin-related protein 1,DRP1)基因沉默对人胃癌细胞株MKN-45奥沙利铂敏感性的影响及其可能的机制.方法 构建靶向DRP1基因的短发夹状RNA(shRNA)慢病毒载体,转染至293T细胞,再感染MKN-45细胞,用qRT-PCR鉴定沉默效率.用终浓度为0.5、1.0、2.0、4.0、8.0、16.0及32.0 μg/ml的奥沙利铂分别处理实验组、阴性对照组(NC组)和空白对照组(CON组),48 h后采用MTT实验检测细胞存活率并计算半数抑制浓度(IC50),流式细胞术检测细胞凋亡,Westem blot检测LC3-Ⅱ和p62表达.结果 实验组的DRP1 mRNA(0.087±0.025)显著低于NC组(1.040±0.020)和CON组(1.027±0.021)(均P＜0.001).随奥沙利铂浓度增加,实验组的细胞存活率明显降低(均P ＜0.001).实验组的IC5.值(14.1±0.4) μg/ml较NC组(20.0±1.1) μg/ml和CON组(20.0±1.8) μg/ml降低(均P＜0.01);实验组的细胞凋亡率(9.4％±1.1％)较NC组(6.4％±0.8％)和CON组(6.5％±1.0％)升高(均P＜0.05);实验组的LC3-Ⅱ(0.36±0.03)较NC组(0.62±0.04)和CON组(0.59±0.07)降低(均P＜0.01);实验组的P62(0.58±0.04)较NC组(0.39±0.04)和CON组(0.36±0.04)升高(均P＜0.01). 结论 DRP1介导的线粒体自噬提高了MKN-45细胞对奥沙利铂的敏感性.

Objective To investigate the effects of DRP1 gene silencing on the chemosensitivity of human gastric cancer MKN-45 cells to oxaliplatin.Methods A lentiviral vector containing short hairpin RNA (shRNA) targeting DRP1 was constructed and cotransfected to MKN-45 cells.Levels of DRP1mRNA was detected by quantitative RT-PCR,With a final concentration of 0.5,1.0,2.0,4.0,8.0,16.0 and 32.0 μg/ml of oxaliplatin processing Lv-shRNA-DRPI group (experimental group),negative control group (NC group),and blank control group (CON group) respectively.Cellular proliferation was determined by MTT assay and calculate half maximal inhibitory concentration (IC5o).Celluar apoptosis was analyzed by flowcytometry.Using Western blot to detect LC3-Ⅱ and p62 expression.Results DRP1mRNA levels in experimental group (0.087 ± 0.025) was significantly inhibited as compared with NC group (1.040 ± 0.020) and CON group (1.027 ± 0.021) (P ＜ 0.001).Cellular survival rate decreased in a oxaliplatin dose-dependent manner (all P ＜ 0.001).IC50 value in experimental group (14.1 ± 0.4) μg/ml dropped compared with NC group (20.0 ± 1.1) μg/ml and CON group (20.0 ± 1.8) pg/ml (both P ＜ 0.01).Celluar apoptosis rates in experimental group (9.4％ ± 1.1％) elevated in contrast with NC group (6.4％ ± 0.8％) and CON group (6.5％ ± 1.0％) (both P ＜ 0.05),expression of LC3 in experimental group(0.36 ± 0.03) dropped compared with NC group (0.62 ± 0.04) and CON group (0.59 ± 0.07) (both P ＜ 0.05),expression of P62 in experimental group (0.58 ±-0.04) increased in contrast with NC group (0.39±0.04) and CON group (0.36 ±0.04) (both P＜0.05).Conclusions DRP1-mediated overactive mitophagy plays a vital role in increasing the sensitivity of gastric cancer cell MKN-45 to oxaliplatin.