外源性FHIT基因对奥曲肽诱导胃癌细胞MGC-803凋亡的影响

目的:探讨外源性脆性组氨酸三联体(fragile histidine triad, FHIT)基因对奥曲肽(octreotide)诱导胃癌细胞凋亡的影响,并探讨其作用机制.方法:采用脂质体法将带有FHIT基因的表达载体pRcCMV-FHIT和空载体pRcCMV分别转入FHIT表达缺失的人类胃癌细胞系MGC-803中.Western 印迹法检测转染细胞中FHIT蛋白的表达.使用不同浓度的奥曲肽(10~(-10)、10~(-9)、10~(-8) 、10~(-7)和10~(-6)mol/L)分别处理各组细胞24、48 和72 h, MTT法检测分析细胞增殖情况,FCM法检测细胞凋亡. Western印迹法检测奥曲肽作用细胞前后,细胞中bcl-2和bax的表达.结果:转染FHIT基因后,胃癌细胞系MGC-803中检测到FHIT蛋白的表达.奥曲肽(10~(-8) mol/L)处理细胞48 h后,转染FHIT基因组细胞的凋亡率为(26.777±1.702)%,与转染空载体组的(13.800±0.511)%和空白细胞组的(12.634±0.479)%相比,凋亡率明显增高(F=245.789,P<0.05,).转染FHIT基因组细胞经奥曲肽处理后bcl-2蛋白表达量减少,bax蛋白表达量增加.结论:外源性FHIT基因表达与奥曲肽可协同促进胃癌细胞MGC-803凋亡,其机制可能与bcl-2家族中的凋亡相关蛋白改变有关.

Effects of exogenous fragile histidine triad gene on apoptosis of MGC-803 gastric cancer cells induced by octreotide

Objective:To investigate the effect of exogenous extopic fragile hisdidine triad (FHIT) gene on the apoptosis of gastric cancer cells induced by octreotide and elucidate the underlying mechanism. Methods: Human gastric cancer cell line MGC-803, which was loss of FHIT gene, was transfected with plasmid pRcCMV-FHIT and pRcCMV via lipofectamine mediation. After transfection, Western blotting was used to analyse the expression of FHIT protein in positive cells screened out by G418. The cells were treated with octreotide 10~(-10), 10~(-9), 10~(-8), 10-7, and 10~(-6) mol/L for 24, 48 and 72 h. Cell proliferation was evaluated by MTT assay and apoptosis by flow cytometry. The expression of bcl-2 and bax protein was detected with Western blotting.Results:FHIT protein expression was detected in MGC-803 gastric cancer cells after FHIT gene transfection. After treatment with octreotide 10~(-8) mol/L for 48 h, the apoptotic rate of MGC-803 cells transfected with FHIT gene was (26.777±1.702)%, significantly higher than that in empty vector group and untransfected group (13.800±0.511)% vs (12.634±0.479)%, F=245.789, P<0.05]. The expression of bcl-2 protein was decreased while the expression of bax protein was increased in FHIT gene transfection group after octreotide treatment. Conclusion:The exogenous FHIT gene and octreotide had strong synergistic effects on apoptosis of MGC-803 cell lines, and their action mechanism may be related to the alteration of the expression of apoptosis-related proteins of bcl-2 family.