HPV16阳性和阴性患者宫颈癌组织中miR-27a-3p和HOXB8蛋白的表达差异及其机制研究

摘要

目的:探讨miR-27a-3p和同源盒B8(HOXB8)蛋白在人乳头瘤病毒16型阳性[HPV16(+)]和阴性[HPV16(-)]患者宫颈癌组织中表达的差异及其机制.方法:选取2012年1月-2016年1月于我院就诊的宫颈癌患者120例,根据其是否感染HPV16分为HPV16(+)组(60例)和HPV16(-)组(60例).采用实时荧光定量聚合酶链反应法检测两组患者宫颈癌组织中miR-27a-3p和HOXB8 mRNA的表达水平,采用蛋白印迹法检测HOXB8蛋白的表达水平,采用巢式降落式甲基化特异性聚合酶链反应法检测miR-27a-3p启动子区DNA甲基化水平,采用染色质免疫共沉淀-定量聚合酶链反应法检测miR-27a-3p启动子区组蛋白甲基化水平;培养人宫颈癌细胞系SiHa细胞株,考察转染miR-27a-3p模拟物(mimic)和抑制物(inhibitor)后miR-27a-3p和HOXB8 mRNA的表达水平.结果:HPV16(+)组患者宫颈癌组织中miR-27a-3p的表达水平显著低于HPV16(-)组患者,HOXB8 mRNA和蛋白表达水平、miR-27a-3p启动子区DNA甲基化水平和组蛋白甲基化水平均显著高于HPV16(-)组患者,差异均有统计学意义(P<0.05或P<0.01).在SiHa细胞转染miR-27a-3p mimic后,miR-27a-3p的表达水平显著升高,而HOXB8 mRNA的表达水平显著降低;转染miR-27a-3p inhibitor后,miR-27a-3p的表达水平显著降低,而HOXB8 mRNA的表达水平则显著升高,差异均有统计学意义(P<0.01).结论:HPV16可能通过启动子区DNA甲基化和组蛋白甲基化下调miR-27a-3p的表达,从而影响宫颈癌的发生与发展,HOXB8蛋白可能是其作用靶点.%OBJECTIVE:To investigate the expression difference and its mechanism of miR-27a-3p and HOXB8 protein in cer-vical cancer tissues of HPV16-positive and HPV16-negative patients. METHODS:A total of 120 patients with cervical cancer in our hospital during Jan. 2012-Jan. 2016 were divided into HPV16-positive group(60 cases)and HPV16-negative group(60 cases) according to HPV16 infection situation. The expression of miR-27a-3p mRNA and HOXB8 mRNA in cervical cancer tissue were de-tected by RT-qPCR. The expression of HOXB8 protein was detected by Western blotting assay. DNA methylation level of miR-27a-3p promoter region was detected by nested-down methylation specific PCR (nMS-PCR). Histone methylation level of miR-27a-3p promoter region was detected by chromatin immunoprecipitation PCR (CHIP-PCR). The expression of miR-27a-3p mRNA and HOXB8 mRNA were detected after transfecting miR-27a-3p mimic and inhibitor into Human cervical cancer cell line SiHa,respectively. RESULTS:The expression of miR-27a-3p in HPV16-positive group was significantly lower than HPV16-nega-tive group,while HOXB8 mRNA and protein expression,DNA and histone methylation levels of miR-27a-3p promoter region were significantly higher than HPV16-negative group,with statistical significance (P<0.05 or P<0.01). After transfecting miR-27a-3p mimic into SiHa cells,the expression of miR-27a-3p was increased significantly,while that of HOXB8 mRNA was de-creased significantly;after miR-27a-3p inhibitor transfection,the expression of miR-27a-3p was decreased significantly,while that of HOXB8 mRNA was increased significantly,with statistical significance(P<0.01). CONCLUSIONS:HPV16 may down-regu-late the expression of miR-27a-3p through DNA methylation and histone methylation of promoter region,so as to influence the gen-eration and development of cervical cancer. HOXB8 may be the target protein of miR-27a-3p.