WNT信号通路在KRAS基因突变型结直肠癌中的作用

Mutations of KRAS involved development of colorectal carcinoma through regulating WNT signaling pathway

目的:探讨WNT信号通路在KRAS基因突变型结直肠癌的作用。方法:收集206例郑州大学第一附属医院结直肠癌患者的临床病理资料及其新鲜组织,采用qRT-PCR方法检测WNT信号通路相关蛋白β-catenin和Cyclin D1 mRNA的表达。将KRAS基因突变的结直肠癌细胞SW480分为β-catenin siRNA组、阴性对照组及空白对照组3组,β-catenin siRNA组和阴性对照组分别转染特异性β-catenin siRNA和si-control,空白对照组细胞只加入含体积分数10%胎牛血清的RPMI 1640培养基,利用MTT法检测细胞增殖,Annexin-V/PI双染法检测细胞凋亡。结果:206例结直肠癌标本中KRAS基因突变率为37.8%;与野生型标本相比,突变型标本WNT信号通路相关蛋白β-catenin和Cyclin D1 mRNA的表达升高(P<0.05)。与阴性对照组和空白对照组相比,β-catenin siRNA组细胞增殖下降(P<0.05)、凋亡升高(P<0.05)。结论:与野生型相比,β-catenin和Cyclin D1两种蛋白在KRAS突变型结直肠癌样本中的表达水平更高,且抑制β-catenin表达后降低了KRAS突变型结直肠癌细胞的增殖,促进了细胞的凋亡。

Aim:To investigate the molecular mechanism of WNT signaling pathway in KRAS mutant colorectal cancer.Methods:The clinicopathological data and fresh tissues of 206 patients with colorectal cancer in the first affiliated Hospital of Zhengzhou University were collected.The mRNA expressions of WNT pathway-related proteinsβ-catenin and Cyclin D1 were detected by using qRT-PCR method.The SW480 cells inβ-catenin siRNA group and negative control group were transfected with specificβ-catenin siRNA and si-control respectively,and the SW480 cells in blank group were cultured in RPMI 1640 with 10%(V/V)fetal bovine serum.MTT assay was used to detect cell proliferation activity.Annexin-V/PI double staining was used to detect cell apoptosis.Results:The mutation rate of KRAS gene in 206 cases of colorectal cancer was 37.8%.The mRNA expressions ofβ-catenin and Cyclin D1 were significantly increased in samples with KRAS mutations compared with those with wild type(P<0.05).Compared with negative control group and blank group,the proliferation of SW480 cells inβ-catenin siRNA group significantly decreased(P<0.05),and the apoptosis of the SW480 cells significantly increased(P<0.05).Conclusion:The expression levels ofβ-catenin and Cyclin D1 proteins were significantly higher in KRAS mutation colorectal cancer samples compared with wild type.And inhibiting the expression ofβ-catenin could inhibit the proliferation and induce the apoptosis of SW480 cells.