不同浓度幽门螺杆菌对胃癌细胞增殖凋亡及FAF1mRNA表达的影响

目的 研究不同浓度幽门螺杆菌（helicobacter pylori,Hp）感染对人胃癌细胞HGC-27生长及Fas相关因子1（fasassociated factor 1,FAF1）m RNA表达的影响,探讨Hp致胃癌发生的分子机制。方法 人胃癌细胞HGC-27与不同浓度Hp标准菌株NCTC11637共培养24 h,根据感染复数（细胞/细菌比）分为1∶1共培养组、1∶50共培养组、1∶100共培养组、1∶200共培养组及对照组（未与Hp共培养）,采用噻唑蓝（MTT）比色法测定0 h、12 h、24 h、48 h的OD值,绘制细胞生长曲线。共培养24 h后以流式细胞仪检测细胞凋亡率,实时荧光定量逆转录聚合酶链反应（q RT-PCR）技术检测HGC-27细胞FAF1 m RNA的相对表达量,比较不同浓度Hp感染前后FAF1 m RNA表达的变化。结果 经革兰氏染色及生化实验证实培养细菌为Hp。与对照组相比,共培养12 h时,1∶50共培养组细胞增殖活性升高（P〈0.05）,1∶1共培养组、1∶100共培养组及1∶200共培养组细胞增殖活性低于对照组（P〈0.05）;共培养24 h、36 h、48 h时,各共培养组细胞增殖活性均低于对照组（P〈0.05）。共培养24 h时,1∶1共培养组及1∶50共培养组细胞凋亡率及FAF1 m RNA的相对表达量与对照组比较,差异无统计学意义（P均〉0.05）;1∶100共培养组及1∶200共培养组细胞凋亡率明显升高,FAF1 m RNA的相对表达量较对照组明显降低（P〈0.05）。结论 Hp感染可导致胃癌细胞增殖凋亡失衡,下调胃癌细胞FAF1 m RNA的表达,FAF1m RNA的表达量与Hp的感染浓度有关,FAF1 m RNA的表达下调可能是Hp致胃癌发生的机制之一。

Effects of different Helicobacter pylori loads on proliferation,apoptosis and FAF1 mRNA expression in gastric cancer cells

Objective To explore the molecular involvement of Helicobacter pylori in gastric cancer by examining the effects of dif- ferent H. pylori loads on proliferation, apoptosis and FAFI mRNA expression in gastric cancer ceils. Method Human gastric carcinoma HGC-27 cells were co-cultured with different amounts of standard H. pylori strain NCTC11637 ;multiplicities of infection （MOIs, bacteria/cells） were O, 1,50,100 and 200. H. pylori was identified based on Gram staining and biochemical tests. Cancer cell proliferation was measured using the thiazolyl blue （MTT） assay after 0,12,24,36 and 48 h of co-culture. After 24 h co-culture,apoptosis in the cancer cells was measured using flow cytometry, and FAF1 mRNA expression was quantitated using fluorescent real-time quantitative RT-PCR. Expression of the β-actin gene was used as a reference for normalizing FAF1 mRNA expression levels. Results After 12 h co-culture, cancer cell proliferation at MOI 50 was significantly greater than at MOI 0 （P〈0.05）,whereas proliferation at other MOIs was lower than at MOI 0 （P〈O.05）. After co-culture for 24,36 and 48 h,cancer cell proliferation at all MOls was significantly lower than at MOI 0 （P〈0.05）. After 24 h co-cuhure,apoptosis levels and relative FAF1 mRNA expression were similar at MOIs O, 1 ,and 50 （P〉O.05）. In contrast, apoptosis levels were significantly higher and relative FAF1 mRNA expression significantly lower at MOIs 100 and 200 than at MOI 0 （P〈0.05）. Conclusion H. pylori infection can suppress proliferation, promote apoptosis and down-regulate FAF1 mRNA expression in gastric cancer cells. Down-regulation of FAF1 mRNA by H. pylori may lead to gastric cancer.