长链非编码RNA CCAT2对结肠癌细胞增殖和凋亡的影响及机制探讨

目的:观察长链非编码RNA（lncRNA）结肠癌相关转录本2（CCAT2）在结肠癌细胞系中的表达及对细胞增殖和凋亡的影响，并探讨其机制。方法:采用荧光定量PCR技术（qRT-PCR）检测结肠癌细胞系HCT116、SW620、LOVO、HT29与正常结肠上皮细胞系NCM460中lncRNA CCAT2的表达。将结肠癌细胞系SW620分成CCAT2-siRNA组、Control-siRNA组及Mock组，CCAT2-siRNA组和Control-siRNA组经LipofectamineTM 2000分别转染CCAT2-siRNA及Control-siRNA，Mock组以PBST作对照。MTT实验和流式细胞术分别测定增殖和凋亡能力，Western blot测定p53、裂解型聚腺苷二磷酸-核糖聚合酶（PARP）及B细胞淋巴瘤/白血病-2（Bcl-2）蛋白的表达。结果:lncRNA CCAT2在结肠癌细胞系LOVO、HT29、HCT116、SW620中均比正常结肠上皮细胞系NCM460表达水平升高（P＜0.05)。MTT示:转染后0 h、24 h、48 h,CCAT2-siRNA组与Control-siRNA组OD490 nm值差异无统计学意义（P＞0.05)。转染后72 h、96 h，CCAT2-siRNA组OD490 nm值低于Control-siRNA组（P＜0.05)。CCAT2-siRNA组细胞凋亡率高于Control-siRNA组（P＜0.01）。与Control-siRNA组相比，CCAT2-siRNA组p53、裂解型PARP表达上调，Bcl-2蛋白表达下调。结论:lncRNA CCAT2在结肠癌细胞系中高表达，敲低lncRNA CCAT2表达可抑制结肠癌细胞增殖，并诱导凋亡，其机制可能与p53、裂解型PARP表达上调，Bcl-2蛋白表达下调有关。

The effects of lncRNA CCAT2 on the proliferation and apoptosis in colon carcinoma cell and its mechanism

Objective:To investigate the expression of lncRNA CCAT2 in colon carcinoma cell lines and its roles on proliferation and apoptosis of colon carcinoma in vitro,and explore the underlying mechanism.Methods:The expression of lncRNA CCAT2 in colon carcinoma cell lines including LOVO,HT29,HCT116,SW620 and normal colon cells was assayed by qRT-PCR.The SW620 cell line was divided into three groups and transfecte CCAT2-siRNA and Control-siRNA and PBST by LipofectamineTM 2000,respectively.MTT assay and flow cytometry was used to measure the proliferation and apoptosis ability.The expression levels of p53,cleaved PARP and Bcl-2 protein was measured by Western blot.Results:Compared with NCM460 cell line,lncRNA CCAT2 was up-regulated expression in colon carcinoma cell lines,including LOVO,HT29,HCT116 and SW620(P＜0.05).MTT showed that there was no significantly difference between CCAT2-siRNA and Control-siRNA group in terms of OD490 nm after transfect for 0 h,24 h and 48 h (P＞0.05).The OD490 nm value of CCAT2-siRNA group was significantly lower than that in Control-siRNA after transfect for 72 and 96 h (P＜0.05).The apoptosis rate of CCAT2-siRNA group was significantly higher than that in Control-siRNA group (P＜0.01).Compared with Control-siRNA group,the p53 and cleaved PARP showed up-regulated expression,while Bcl-2 showed down-regulated expression.Conclusion:lncRNA CCAT2 was over-expressed in colon carcinoma cell lines.siRNA-mediated CCAT2 knockdown inhibits the cell proliferations and promotes apoptosis of colon cancer cells in vitro,possibly by activating apoptosis signaling pathway.