Human MicroRNA-602 Inhibits Hepatitis C Virus Genotype 1b Infection and Promotes Tumor Suppressor Gene Expression in a Hepatoma Cell Line
Objective: Hepatitis C virus (HCV) infects 200 million people worldwide, inducing cirrhosis and hepatocellular carcinoma. Liverspecific microRNA (miR) miR-122 facilitates HCV replication, and Locked Nucleic Acid (LNA)-anti-miR-122 was used successfully as a mono-therapy in HCV infected patients. Studies show that anti-miR-122 may negatively impact hepatocyte metabolism. Previously, we showed that human (hsa) miR-602 relative intracellular expression was up-regulated in microarray profiling when transfected with HCV genotype 1b, and hsa-miR-602 lowered HCV accumulation in infected Huh-7.5 cells. This study compares the effectiveness of hsa-miR-602 and LNA-anti-miR-122 on inhibiting HCV replication and regulating the expression of tumor suppressor genes p53, p73, and RASSF1A.
Methods: Huh-7.5 cells were transfected with HCV genotype 1b and treated with hsa-miR-602, LNA-anti-miR-122 or both. Cytopathic effect (CPE) and cell aggregation were observed regularly after transfection. HCV load and localization in the un-transfected, transfected, and treated cells were detected by qRT-PCR and immunostaining, respectively. qRT-PCR detected the expression of p53, p73, and RASSF1A. The Cancer Cell Lines Encyclopedia (CCLE) and The Cancer Genome Atlas (TCGA) were used to correlate gene copy number and expression for TP53, TP73 and RASSF1A in normal and hepatocellular carcinoma (HCC) patient tissues and HCC cell lines. The survival curve for patients with MIR- 602 expression was done using TCGA HCC clinical data sets.
Results: HCV load decreased in all treated cells but was more pronounced with hsa-miR-602. HCV transfected Huh-7.5 cells treated with hsa-miR-602 showed no morphological changes whereas cells treated with LNA-anti-miR-122 or LNA-anti-miR-122 and hsa-miR-602 together showed morphological changes. p53, p73, RASSF1A were down-regulated in HCV transfected cells and all treatments restored expression to near normal levels. Similar down-regulated expression was seen in the HCC patient samples and cell lines.
Conclusion: Hsa-miR-602 effectively reduces HCV load and restores p53, p73, and RASSF1A expression in HCV transfected cells.