DNMT3B基因在肝细胞癌中的表达及其对肝癌细胞增殖和侵袭迁移的影响
Expression of DNMT3B gene in hepatocellular carcinoma and its effect on proliferation, invasion and metastasis of hepatoma cells

摘要：目的 探讨DNA甲基转移酶3b(DNMT3B)基因在肝细胞癌(HCC)组织中的表达及其对肝癌细胞增殖、侵袭迁移的影响及机制。方法 收集46例肝癌患者的癌组织与对应癌旁组织，qRT-PCR法检测DNMT3B在肝癌组织及对应癌旁组织中的表达，并分析其与临床病理特征之间的关系；应用RNA干扰(RNAi)技术合成针对DNMT3B的siRNA并转染MHCC97-H细胞，qRT-PCR和Western blot检测相关基因mRNA和蛋白表达；MTT法检测细胞增殖能力，Transwell实验检测细胞侵袭和迁移能力。结果 46例肝癌患者中，DNMT3B基因在肝癌组织中的表达较对应癌旁组织升高者占73.91%，其高表达与肝癌的病理分化类型和肿瘤大小有关(P均<0.05)；在细胞水平，抑制DNMT3B基因表达使MHCC97-H细胞增殖及侵袭迁移能力降低；干扰DNMT3B基因可以增加抑癌相关基因RASSFA1、APC、MTSS1 mRNA和蛋白表达水平。结论 DNMT3B与肝癌的进展密切相关，它可能通过调控下游抑癌基因甲基化水平影响其表达，从而抑制肝癌细胞的增殖及侵袭迁移能力。
ABSTRACT: Objective To investigate the expression of DNA methyltransferase 3b (DNMT3B) in hepatocellular carcinoma (HCC) and its effect and mechanism on the proliferation, invasion and migration of HCC cells. Methods The expression of DNMT3B gene was detected by qRT-PCR in 46 cases of HCC tissues and corresponding adjacent tissues; the results and clinical pathological parameters were analyzed. SiRNA targeting DNMT3B was transfected into MHCC97-H cells by RNA interference (RNAi) technique. The mRNA and protein expression levels of related genes were detected by qRT-PCR and Western blot. The cell proliferation was measured by MTT assay, and the invasion nd migration abilities were measured by Transwell assay. Results In 46 HCC patients, the expression of DNMT3B (73.91%) was significantly higher in HCC than in adjacent normal tissue. The high expression of DNMT3B gene was associated with histological type and tumor size of HCC (all P<0.05). Inhibition of DNMT3B gene expression decreased proliferation, invasion and migration of MHCC97-H cells. Interference with DNMT3B gene increased the expressions of tumor suppressor genes RASSFA1, APC and MTSS1 at mRNA and protein levels.Conclusion DNMT3B is associated with the progression of HCC. It may inhibit the proliferation, invasion and migration of HCC cells by regulating the methylation of downstream tumor suppressor gene