胃癌组织中miR-497表达及其生物学意义

目的检测胃癌组织和癌旁组织中miR-497的表达差异，寻找其下游作用靶点。方法选取2010-2013年期间在中国医科大学附属第一医院胃肠外科手术切除的94例胃癌及其癌旁组织。用RT-PCR法定量检测miR-497在其中的表达；在线软件预测miR-497靶基因，用阴性对照及miR-497-mimics转染SGC-7901细胞系，RT-PCR及Western检测胃癌细胞miR-497过表达后靶点基因mRNA及蛋白水平的改变；MTT法检测miR-497-mimics组（miR-497过表达）细胞株与阴性对照组间对5-氟尿嘧啶（5-FU）化疗的敏感性。结果①miR-497表达量在胃癌组织中明显低于癌旁组织，差异有统计学意义（P〈0．01）。②BCL2L2被预测为miR-497的靶基因，miR-497在胃癌SGC-7901细胞中过表达后BCL2L2蛋白表达在miR-497-mimics组细胞中明显弱于阴性对照组细胞，BCL2L2mRNA在2组细胞中的表达差异无统计学意义（P〉0．05）。miR-497-mimics组细胞对5-FU的Ic50值明显低于阴性对照组细胞（P=0．0046）。结论miR-497在胃癌组织中低表达，BCL2L2为miR-497的靶基因，miR-497过表达可提高胃癌细胞对5-Fu的敏感性，这为进一步研究miR-497与BCL2L2在胃癌中的作用及治疗提供了新的方向。

Expression of MicroRNA-497 in Gastric Cancer and Its Biological Significance

Objective To detect the expression of microRNA-497 （miR-497） in gastric cancer and its biological significance, and to find out its regulatory links with other genes and investigate the effect of miR-497 overexpression interference on chemotherapy sensitivity of gastric cancer cell line. Methods Ninety-four gastric cancer tissues and adjacent to cancer tissues from 2010 to 2013 in this hospital were collected. The expression of miR-497 in the gastric cancer tissue or adjacent to cancer tissue was detected by real-time PCIL SGC-7901 cell line was transfected by miR- 497-negative control and miR-497-mimics, respectively. The BCL2L2 expression was measured by Western blot after upregnlation ofmiR-497. The chemotherapy sensitivity of cell line was tested by MTT assay. Results ① The expression of miR-497 was significantly downregnlated in the gastric cancer tissues as compared with the adjacent to cancer tissues （P〈 0. 01）. ② BCL2L2 was predicted to target gene of miR-497. After miR-497 overexpression in cells, the expression of BCL2L2 protein was decreased in the miR-497-mimics cells as compared with negative control cells. The IC50 in the miR-497-mimics cells was significantly lower than that in the negative control cells （P=0. 004 6）. Conclusions miR-497 expression is frequently downregnlated in gastric cancer tissue. Overexpression of miR-497 could inhibit the expression of target gene BCL2L2, and improve chemotherapy sensitivity of gastric cancer cell line, which implies that miR-497 may play an important role in carcinogenesis and therapy of gastric cancer.