PARP-1在脱氧胆酸钠促结肠癌细胞增殖中的作用

Effect of PARP-1 on Proliferation of Colon Cancer Cells Induced by Sodium Deoxycholate

结肠癌的发生与肠腔内脱氧胆酸引起的DNA损伤有关,聚腺苷二磷酸核糖聚合酶-1（PARP-1）对DNA损伤具有修复作用.目的：探讨PARP-1在脱氧胆酸钠促结肠癌细胞增殖中的作用及其可能机制.方法：选用不同浓度的脱氧胆酸钠、PARP-1抑制剂5-氨基异喹啉酮（5-AIQ）或两者联合分别作用于人结肠腺癌细胞株HT-29.MTT实验检测细胞增殖情况,流式细胞仪检测细胞周期和细胞凋亡,免疫细胞化学染色检测环氧合酶-2（COX-2）、caspase-3、PARP-1蛋白表达.结果：10～50 μmol/L脱氧胆酸钠能促进HT-29细胞增殖,增加COX-2、PARP-1蛋白表达,减低caspaae-3蛋自表达.100μmol/L 5-AIQ单独作用对HT-29细胞增殖无明显影响,但能减低COX-2、PARP-1蛋白表达.与单独作用相比,10μmol/L脱氧胆酸钠与100 μmol/L 5-AIQ联合能显著抑制HT-29细胞生长,阻滞细胞周期,诱导细胞凋亡,COX-2、PARP-1蛋白表达减低,caspase-3蛋白表达无明显变化.结论：COX-2与PARP-1在脱氧胆酸钠促结肠癌细胞增殖的过程中可能存在相互作用,PARP-1抑制剂5-AIQ可能用于预防脱氧胆酸诱发的结肠癌.

Background： It is reported that DNA damage induced by colonic luminal deoxycholic acid is involved in colon carcinogenesis, and DNA damage can be repaired by poly（ADP-ribose） polymerase-1 （PARP-1）. Aims： To investigate the effect of PARP-1 on proliferation of colon cancer cells induced by sodium deoxycholate and its potential mechanism. Methods： Human colon adenocarcinoma cell line HT-29 was treated with different concentrations of sodium deoxycholate, 5-aminoisoquinolinone （5-AIQ, an inhibitor of PARP-1） and their combination, respectively. The proliferation activity of HT-29 cells was measured by MTT assay, the cell cycle and apoptosis were analyzed by flow cytometry, and the protein expressions of eyclooxygenase-2 （COX-2）, caspase-3 and PARP-1 were determined by immunocytochemical stain. Results： Sodium deoxycholate （10-50 μmol/L） enhanced the proliferation of HT-29 cells, increased COX-2 and PARP-1 expressions and decreased easpase-3 expression, while 5-AIQ （100 μmol/L） inhibited the expressions of COX-2 and PARP-1 but had no obvious effect on cell proliferation. Compared with sodium deoxycholate （10 μmol/L） alone, co- administration of sodium deoxycholate （10 μmol/L） and 5-AIQ （100 μmol/L） suppressed the proliferation of HT-29 cells, arrested cell cycle and induced apoptosis, concomitantly with a decrease of COX-2 and PARP-1 expressions and an unchanged caspase-3 expression. Conclusions： There might be an interaction between COX-2 and PARP-1 in the process of proliferation of colon cancer cells induced by sodium deoxycholate. 5-AIQ, the inhibitor of PARP-1, might be a promising agent in preventing colon cancer induced by deoxycholic acid.