| Objective: To discuss the function of microRNA-148a (miRNA-148a) in hepatocarcinogenesis through acting the DNA methyltransferase 1 to maintain its oneself CpG island methylation .Methods: (1)Quantitative real-time PCR was performed to detect miRNA-148a expression in different liver tissues. (2)Quantitative real-time PCR and western blot were employed to detect the mRNA and protein expression of DNMT1 and RASSF1A. (3)The activity of DNMT1 was down regulated with DNMT1 siRNA transfection, and then quantitative real-time PCR and western blot were used to detect the expression change of DNMT1 and RASSF1A mRNA and protein in HepG2.(4) The activity of miRNA-148a was up regulated with miRNA-148a mimic transfection, and then quantitative real-time PCR and western blot were used to detect the expression change of miRNA-148a, DNMT1 and RASSF1A mRNA and protein in HepG2. (5)Transwell and CCK-8 were performed to detect invasion and proliferation changes of HepG2.Result: (1)MiRNA-148a mRNA was underexpressed in para-tumoral tissues and HCC compared to normal liver tissues.And the miRNA-148a degree of decline in bulky and metastatic HCC is relative large.(2)DNMT1 mRNA and protein was overexpressed in para-tumoral tissues and HCC compared to normal liver(.3)DNMT1 mRNA and protein expression in HepG2 was downregulated after DNMT1 siRNA transfection. , RASSF1A mRNA and protein expression in HepG2 was upregulated after DNMT1 siRNA transfection. (4)DNMT1 mRNA and protein expression in HepG2 was downregulated after miRNA-148a mimics transfection. , but miRNA-148a,RASSF1A mRNA and protein expression in HepG2 was upregulated after miRNA-148a mimics transfection. (5)The invasiveness and proliferation of HepG2 were significantly reduced after miRNA-148a mimics transfection. Conclution: The inhibition of tumor suppressor genes RASSF1A, which is caused by the loss of inhibition of DNMT1 resulted by the low expression of miRNA-148a, may be an important mechanism for hepatocarcinogenesis. |
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