阻断自分泌性胃泌素对胃癌SGC-7901细胞增殖和凋亡的影响

目的 探讨胃癌组织中是否存在胃泌素／胆囊收缩素（CCK）-B受体自分泌环及其在胃癌的发生发展中的作用。方法 采用人胃癌细胞系SGC-7901在含10％新生小牛血清RPMI-1640培养基中培养于37％、5％CO：的培养箱中。SGC-7901细胞中胃泌素／CCK-B受体自分泌环的检测分别用逆转录-聚合酶链反应（RT-PCR）、免疫细胞化学及放射免疫分析法。抗胃泌素单克隆抗体阻断自分泌环对细胞生长与凋亡的影响采用SGC-7901细胞与不同浓度的抗胃泌素单克隆抗体共同孵育72h后,搜集细胞,分别用四甲基偶氮唑盐比色法及流式细胞术检测细胞生长率、细胞周期及凋亡细胞,以不加抗体孵育作为阴性对照。结果 SGC-7901细胞复合表达CCK-B受体和胃泌素基因,其序列已被测序证实。胃泌素蛋白主要在SGC-7901细胞的胞质中表达,且培养液中的胃泌素浓度随培养时间的延长和细胞数的增加而增加。用抗胃泌素单克隆抗体阻断此自分泌环后,细胞的生长率从正常对照的100％降至31．4％（抗体浓度为2μg／ml）,而S期细胞数从正常对照的27．8％降至9．5％（抗体浓度为1．2μg／ml）,且细胞凋亡率分别从正常对照的0．9％（亚G1峰法）和1．1％（膜联蛋白-V／碘化丙啶双染法）升至6．5％（亚G1峰法）和7．5％（膜联蛋白-V／碘化丙啶双染法）。结论 胃癌细胞系SGC-7901中存在胃泌素／CCK-B受体自分泌环,阻断此自分泌环后能抑制细胞增殖,促进细胞凋亡。

Blocking the gastrin/cholecystokinin-B receptor autocrine loop influences the growth and apoptosis of human gastric cancer cells

Objective To study whether gastrin/cholecystokinin-B (CCK-B) receptor autocrine loop exists in human gastric cancer cells and the effects of gastrin/CCK-B receptor autocrine loop on the growth and apoptosis of human gastric cancer cells. Methods Human gastric cancer cells of the line SGC-7901 were cultured . The expression of gastrin and CCK-B was detected by RT-PCR, immunocytochemistry and radioimmunoassay. Antibody against gastrin was added so as to block the autocrine loop to observe the growth rate, cell cycle and apoptosis by 3-(4. 5-dimethylthiaxol-z-yl) -2,5- dipheny tertraxolium blue (MMT) colorimetric assay and flow cytometry (FCM). Results The SGC-7901 cells co-expressed gastrin and CCK-B receptor mRNAs, confirmed by sequencing, thus forming gastrin/the CCK-B receptor autocrine loop. After the blocking of the autocrine loop by antibody against gastrin, the cell growth rate and the number of cells residing in the S-phase of the cell cycle decreased and the apoptotic rate increased in an antibody concentration-dependent manner. Conclusion Human gastric cancer SGC-7901 cells possess the gastrin/ the CCK-B receptor autocrine loop. Blocking the autocrine loop inhibits the cell proliferation and promotes the cell apoptosis.