SMYD2通过抑制APC2激活WNT/β-catenin通路影响结直肠癌细胞的迁移和侵袭

SMYD2 promotes the migration and invasion of colorectal cancer cells by activating WNT/β-catenin pathway via APC2

目的:探讨SET和MYND域包含蛋白质2(SET and MYND domaincontaining protein 2,SMYD2)调控结直肠癌(colorectal cancer,CRC)细胞迁移和侵袭的机制。方法:从徐州医科大学附属医院收集2019年08月至2020年03月的24对结直肠癌及癌旁组织,进行实时荧光定量PCR(quantitative real-time PCR,qRT-PCR)分析SMYD2的表达量。构建SMYD2和腺瘤性息肉病蛋白2(adenomatous polyposis coli 2,APC2)的小干扰RNA,使用Transwell和蛋白免疫印迹实验检测转染后结直肠癌细胞的迁移和侵袭能力。结果:癌组织中SMYD2的mRNA和蛋白表达量显著高于癌旁组织(P<0.001,P<0.05),且结直肠癌细胞系SW480和HCT116中SMYD2的表达量显著高于正常结直肠细胞系FHC(P<0.001)。在SW480和HCT116细胞中敲低SMYD2后细胞的迁移和侵袭能力减弱(P<0.01),同时E-cadherin的表达量升高(P<0.001),而N-cadherin和Vimentin的表达量降低(P<0.01)。生物信息学分析显示,SMYD2与APC2的表达呈负相关(P<0.001),且APC2可以抑制WNT/β-catenin通路。在SW480和HCT116细胞中敲低SMYD2后APC2的表达量增高(P<0.001),而WNT/β-catenin通路中的β-catenin、c-MYC和CyclinD1表达降低(P<0.01)。敲低APC2可以恢复SMYD2敲低引起的SW480和HCT116细胞的迁移和侵袭降低(P<0.001),E-cadherin升高(P<0.001)和N-cadherin、Vimentin、β-catenin、c-MYC、CyclinD1降低(P<0.01)。结论:在结直肠癌细胞中,SMYD2通过抑制APC2激活WNT/β-catenin通路促进结直肠癌细胞的上皮-间质转化(epithelial-mesenchymal transition,EMT),从而影响细胞的迁移和侵袭能力。

Objective:To investigate the mechanism of SET and MYND domaincontaining protein 2(SMYD2)regulating the metastasis of colorectal cancer(CRC)cells.Methods:24 pairs of CRC adjacent tissues from August 2019 to March 2020 were collected from Affiliated Hospital of Xuzhou Medical University,and the expression of SMYD2 was analyzed by quantitative real-time PCR(qRT-PCR).Small interfering RNA(siRNA)of SMYD2 and adenomatous polyposis coli 2(APC2)were constructed and Transwell and Western Blot(WB)assay were conducted to detect the metastasis ability of CRC cells after transfection.Results:The mRNA and protein expression of SMYD2 in cancer tissues was significantly higher than that in adjacent tissues(P<0.001,P<0.05).The expression of SMYD2 in colorectal cancer cell lines SW480 and HCT116 are significantly higher than normal colorectal cell lines FHC(P<0.001).After knocking down SMYD2 in SW480 and HCT116 cells,the cell migration and invasion ability were weakened(P<0.01).Simultaneously,knockdown SMYD2 in SW480 and HCT116 cells increased the expression of E-cadherin(P<0.001)while the expression of N-cadherin and Vimentin decreased(P<0.01).Bioinformatics analysis showed that SMYD2 was negatively correlated with the expression of APC2(P<0.001),and APC2 has been confirmed as an inhibitor of WNT/β-catenin pathway.After knocking down SMYD2 in SW480 and HCT116 cells,the expression of APC2 increased(P<0.001),while molecules in the WNT/β-catenin pathway such asβ-catenin,c-MYC and CyclinD1 decreased(P<0.01).APC2 knockdown could rescue the decrease of migration and invasion(P<0.001),the increased expression of E-cadherin(P<0.001)and the decreased expression of N-cadherin,Vimentin,β-catenin,c-MYC and CyclinD1(P<0.01)which caused by SMYD2 knockdownin SW480 and HCT116 cells.Conclusion:SMYD2 promotes epithelial-mesenchymal transfection(EMT)of CRC cells by inhibiting APC2 to activate the WNT/β-catenin pathway,thereby affecting the ability of migration and invasion.