胃癌细胞中环氧合酶-2对延迟整流性钾通道调控机制的研究  

The mechanism of delayed rectifier potassium channel regulated by cyclooxygenase -2 in gastric cancer cells

作　　者：邵晓冬[1] 吴开春[1] 郭晓钟[2] 谢满江[3] 张靖[1] 樊代明[1] 

机构地区：[1]第四军医大学西京医院消化科,西安710032 [2]沈阳军区总医院消化科 [3]第四军医大学航空航天医学系

出　　处：《中华消化杂志》2009年第1期46-49,共4页Chinese Journal of Digestion

基　　金：国家自然科学基金资助项目（30400204）

摘　　要：目的探讨胃癌细胞中环氧合酶（COX）-2对延迟整流性钾通道（HERG）电流的影响和相应的调控机制。方法①采用逆转录聚合酶链反应（PCR）、Western印迹和膜片钳技术检测环氧合酶（COX）-2反义载体转染胃癌细胞前后HERG mRNA、蛋白和电流的变化。②采用酶联免疫吸附试验检测COX-2反义载体转染胃癌细胞前后环磷酸腺苷（cAMP）水平的变化。③采用PCR技术构建缺失cAMP结合结构域的HERG突变体，并转染胃癌细胞。④应用COX-2抑制剂和前列腺素（PG）E2作用于胃癌细胞和HERG突变体转染的胃癌细胞，观察HERG电流的变化。⑤将cAMP的拟似剂和拮抗剂、蛋白激酶（PK）A抑制剂分别作用于胃癌细胞和HERG突变体转染的胃癌细胞，观察相应的HERG电流变化。结果①与亲本细胞相比，COX-2反义转染胃癌细胞的HERG mRNA和蛋白表达无变化，而HERG电流强度减弱（P〈0．05）。②与亲本细胞相比，COX-2反义转染胃癌细胞中的cAMP水平明显下降（P〈0．05）。③COX-2抑制剂减弱而PGE2增强HERG电流的强度。但在缺失cAMP结合域的HERG突变体转染后的胃癌细胞，COX-2抑制剂和PGE2对HERG电流未产生明显的影响。④cAMP拟似剂可增强SGC7901细胞的HERG电流，而cAMP拮抗剂则减弱其电流。但对于缺失cAMP结合结构域的突变体转染的胃癌细胞中的HERG电流，cAMP的拟似剂和拮抗剂均未显示出明显的增强或抑制作用。⑤PKA抑制剂对SGC7901细胞和突变体转染的胃癌细胞的HERG电流均无明显影响。结论COX-2通过其代谢产物PGE2而影响HERG电流。PGE2通过与受体结合后影响cAMP浓度，而cAMP通过与HERG蛋白上的特殊结构域结合对HERG电流产生影响，此过程不受PKA的调控。Objective To investigate the currents impact on delayed rectifier potassium （HERG）regulated by cyclooxygenase （COX）-2 in gastric cancer cells and its mechnism. Methods ① The HERG mRNA, protein and current in gastric cancer cells transfected with or without COX-2 antisense vector were measured by RT-PCR, Western blot and patch-clamp, respectively. ② cAMP concentration in gastric cancer cells transfected with or without COX-2 antisense vector was measured by ELISA. ③ The mutant HERG, which was absence of cAMP-binding domain, was constructed by PCR and transfected into gastric cancer cells.④ The impact of COX-2 inhibitor and proglandin （PG） E2 on HERG current in gastric cancer cells transfected with or without mutant HERG was investigated by patch clamp. ⑤ The effects of agonist and antagonist of cAMP and inhibitor of protein kinase （PK） A on HERG current in gastric cancer cells transfected with or without HERG mutant were observed by patch clamp. Results① The expression of HERG mRNA and protein in gastric cancer cells transfected with COX-2 antisense vector were not altered, but the amplitude of HERG current was diminished （P〈0.05）. ② The cAMP concentration in gastric cancer cells transfected with COX-2 antisense vector was lower than that in parental gastric cancer cells （P〈0.05）. ③ COX-2 inhibitor and PGE2 had influence on the HERG currents in gastric cancer cells. COX 2 inhibitor reduced and PGE2 enhanced the amplitude of HERG current in gastric cancer cells. However, neither COX-2 inhibitor nor PGE2 showed any negative or positive effects on currents of mutant HERG. ④ cAMP agonist enhanced the amplitude of HERG current and cAMP antagonist reduced the amplitude in gastric cancer cells. Neither agonist nor antagonist had effect on currents of mutant HERG. ⑤ PKA inhibitor did not influence the HERG current of parental gastric cancer cells and gastric cancer cells transfeeted with mutant. Conclusions COX-2 regulates HERG current through its catalytic product of PGE2,

关 键 词：胃肿瘤 环氧合酶-2 钾离子通道 

分 类 号：R686[医药卫生—骨科学]