DNA methyltrans-ferase 3b regulating the Cyclin D1 gene expression by microRNA-145 in the human hepatocellular carcinoma cell line

Abstract

Objective To discuss the mechanism of the DNA methyltrans-ferase 3b (DNMT3b) regulating the Cyclin D1 gene expression in SMMC7721 cell line.Methods DNMT3b small interfering RNA (siRNA) was transfected into SMMC-7721 cells.Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect the expression of the microRNA (miR)-145 and Cyclin D1 mRNA.MSP was used to detect whether the promoter of miR-145 was methylated.Results DNMT3b has been successfully suppressed in the culture cells transfected by miR-145 with a transfection efficiency over 90％ ; The methylation status of miR-145 gene showed no significant differences between two groups (P ＞0.05) ; The expression of miR-145 was significantly higher than in control group (P ＜ 0.01) and the change between two groups had no difference (P ＞ 0.05).Conclusion DNMT3b can regulate the expression of Cyclin D1 by miR-145,affect the cell cycle and cause a large number of apoptosis of SMMC-7721 cells. Key words: Carcinoma, hepatocellular; DNA methyltrans-ferase 3b; Cyclin D1; Small interfering RNA; MicroRNA-145