Abstract
BackgroundPersistent infection with hepatitis B virus (HBV) accounts for the majority of hepatocellular carcinoma (HCC), but the molecular mechanisms underlying liver carcinogenesis are still not completely understood. Increasing evidence demonstrates that microRNAs (miRNAs) play significant functional roles in virus–host interactions. The aim of this study was to explore differentially expressed miRNA profiles and investigate the molecular mechanism of miR-0308-3p in HBV-positive HCC carcinogenesis.MethodsHigh-throughput sequencing was used to detect novel miRNAs in three samples of HBV-positive HCC tissue compared to matched HBV-negative HCC tissue. The Cancer Genome Atlas (TCGA) database was used to mine miRNAs related to HBV-positive HCC. Bioinformatics analyses were conducted to predict the miRNAs’ possible biological and pathway regulatory functions. Quantitative polymerase chain reaction (qPCR) was then applied to evaluate the expression levels of randomly selected miRNAs. CCK-8 was used to measure cell proliferation and cell cycles were analyzed using flow cytometry. A dual luciferase reporter gene assay was used to confirm the downstream targets of miR-0308-3p.ResultsIn total, there were 34 overlapping miRNAs in both our miRNA-seq data and the TCGA database. We found two overlapping miRNAs in both the HBV-positive HCC samples and the TCGA database, and 205 novel pre-miRNA sequences were predicted. miR-522 and miR-523 were markedly overexpressed in HBV-positive HCC and were associated with a significantly poorer long-term prognosis (miR-522, HR 2.19, 95% CI 1.33–3.6, p = 0.0015; miR-523HR 1.5, 95% CI 1–2.44, p = 0.0047). Of note, we found that the novel miR-0308-3p was markedly downregulated in HBV-positive HCC samples and HCC cancer cell lines compared with HBV-negative HCC samples and adjacent normal hepatic tissue. Moreover, elevated expression of miR-0308-3p was found to inhibit proliferation of cancer cells by promoting G1/S cell cycle arrest but did not influence the apoptosis of cancer cells. A dual luciferase reporter activity assay identified that miR-0308-3p acted directly on the target sequence of the CDK6 and Cyclin D1 mRNA 3ʹUTR to suppress CDK6 and Cyclin D1 expression.ConclusionsMiR-0308-3p upregulation dramatically suppressed HCC cell proliferation and induced G1/S cell cycle arrest by directly targeting CDK6/Cyclin D1. These findings reveal a novel molecular mechanism for activation of G1/S arrest in HCC and may prove clinically useful for developing new therapeutic targets.
Highlights
Hepatocellular carcinoma (HCC) comprises the vast majority of primary liver cancers [1]; it is the sixth most prevalent cancer and third most frequent cause of cancer-associated deaths worldwide [2]
A dual luciferase reporter activity assay identified that miR-0308-3p acted directly on the target sequence of the CDK6 and Cyclin D1 mRNA 3ʹ-untranslated region (3ʹUTR) to suppress CDK6 and Cyclin D1 expression
MiR-0308-3p upregulation dramatically suppressed hepatocellular carcinoma (HCC) cell proliferation and induced G1/S cell cycle arrest by directly targeting CDK6/Cyclin D1. These findings reveal a novel molecular mechanism for activation of G1/S arrest in HCC and may prove clinically useful for developing new therapeutic targets
Summary
Hepatocellular carcinoma (HCC) comprises the vast majority of primary liver cancers [1]; it is the sixth most prevalent cancer and third most frequent cause of cancer-associated deaths worldwide [2]. Approximately 240 million people are chronically infected with HBV, and approximately 25% of those affected eventually develop HCC. Approximately 60% of HCC cases in Africa and Asia are associated with HBV infection [9]. The mechanism for HBV-positive HCC is still poorly understood. A better understanding of the molecular mechanisms underlying HBV-positive HCC carcinogenesis would help in the development of more effective molecular-targeted interventions for the primary prevention and treatment of HCC. Persistent infection with hepatitis B virus (HBV) accounts for the majority of hepatocellular carcinoma (HCC), but the molecular mechanisms underlying liver carcinogenesis are still not completely understood. The aim of this study was to explore differentially expressed miRNA profiles and investigate the molecular mechanism of miR0308-3p in HBV-positive HCC carcinogenesis
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have