Downregulation of MicroRNA-145 Caused by Hepatitis B Virus X Protein Promotes Expression of CUL5 and Contributes to Pathogenesis of Hepatitis B Virus-Associated Hepatocellular Carcinoma
Downregulation of MicroRNA-145 Caused by Hepatitis B Virus X Protein Promotes Expression of CUL5 and Contributes to Pathogenesis of Hepatitis B Virus-Associated Hepatocellular Carcinoma
Blog Article
Background: Hepatitis B viral infection-induced Glass Defrost Element hepatocellular carcinoma (HCC) is a major threat to human health in China.Hepatitis B virus X protein (HBX), an HBV protein, has been reported to be involved in regulating the cellular activities of the host cells and is responsible for HCC oncogenesis.Methods and Results: In this study, we performed real-time PCR in tumor tissue samples collected from 53 HCC patients (25 HBV-positive cases and 28 HBV-negative cases) to screen the candidate miRNAs that have previously been reported to be aberrantly expressed in HBV-associated HCC and found that miR-145 was significantly downregulated.The following computational analysis identified CUL5 and RAB5C as virtual targets of miR-145, whereas only CUL5 was verified as a validated target gene of miR-145 in liver cells via luciferase reporter assay.
In line with this result, we found that both the mRNA and protein expression levels of CUL5 were significantly higher in HBV-positive Hair Set than in HBV-negative HCC.An in vitro experiment demonstrated a significant decrease in the expression of miRNA-145, a substantial increase in the mRNA and protein expression of CUL5, and an enhanced proliferation of HBX over-expressing HepG2 cells compared with the control.In HepG2.2.
15, we found significant decreases in both the expression of CUL5 and the cell growth rate of H cells transfected with 60 nM miR-145 mimics compared with the scramble controls.Conclusion: HBV infection promotes cell growth, at least partially, through the HBX-induced downregulation of miRNA-145 expression, which is responsible for the oncogenesis of HBV-associated HCC.