幽门螺杆菌对人胃癌MKN45细胞p38MAPK信号转导通路激活作用的研究

背景与目的: 环氧合酶2(cyelooxygenase-2,COX-2)是花生四烯酸转化为前列腺素(prostaglandins,PGs)代谢中重要的限速酶,幽门螺杆菌(Helicobacterpylori,Hp)感染诱导胃黏膜COX-2的过度表达是胃癌发生的重要环节,但Hp感染胃黏膜细胞COX-2表达的机制尚不清楚.本研究旨在揭示Hp对人胃癌MKN45细胞COX-2表达和p38MAPK信号通路的影响,探讨COX-2表达的可能机制.方法: 采用实时荧光定量PCR(real time-PCR)检测Hp标准株NCTC11637感染对人胃痛MKN45细胞COX-2 mRNA转录的影响,Western blot检测坳COX-2蛋白表达的影响和p38MAPK信号通路的激活及其下游因子ATF-2的表达.结果: Hp感染人胃癌MKN45细胞后,COX-2 mRNA的表达明显上调,Hp感染3、6、9、12 h后COX-2 mRNA的表达量分别为正常值的3倍、7.2倍、5.1倍和4.3倍,各时间组COX-2 mRNA表达均明显高于对照组(P＜0.01);Up与MKN45细胞共培养24 h后,COX-2蛋白的表达亦显著增加(P＜0.01).Hp感染MKN45 20 min后,p38MAPK信号通路被激活,60 min达峰值;p38MAPK下游因子ATF-2的表达也明显增加,2 h达高峰,随着作用时间的延长,表达逐渐下降,24 h仍有表达.结论: Hp感染能诱导人胃癌MKN45细胞COX-2的表达;激活p38MAPK信号通路,增加其下游因子ATF-2的表达,可能是其诱导COX-2表达的机制.

Study of Helicobacterpylori on p38MAPK signal transduction pathway activation in gastric epithelial cancer cells line MKN45

Background and purpose:Cyclooxygenase-2 (Cyclooxygenase-2,COX-2) is an important rate-limiting enzyme that is responsible for transformation of arachidonic acid into prostaglandins(PGs).Although Helicobacter pylori(Hp) infection-induced gastric over-expression of COX-2 (COX-2) is an important factor of gastric cancer,the mechanism of COX-2 expression in gastric mucosa cells infected with Hp is still not clear.Our study was to reveal the effect of Hp on expression of COX-2(cyclooxygenase-2),the impact of p38...