Background
Hepatitis B virus (HBV) is a top contributor to hepatoma. Circular RNAs (circRNAs) have been elucidated to have a close connection with HBV-induced hepatoma. This study aimed to explore the role of circRNA BTB domain and CNC homolog 1 (circBACH1) in HBV replication and hepatoma progression, as well as the potential mechanistic pathway.
Conclusion
CircBACH1 knockdown had inhibitory effects on HBV replication and hepatoma progression, at least partly by modulating the miR-200a-3p/MAP3K2 axis.
Methods
Quantitative real-time polymerase chain reaction (qRT-PCR) assay was performed to assess the expression of circBACH1, microRNA (miR)-200a-3p, and mitogen-activated protein kinase kinase kinase 2 (MAP3K2). HBV replication was determined by enzyme-linked immunosorbent assay (ELISA) and qRT-PCR assay. Cell viability and clonogenicity were detected via Cell Counting Kit-8 (CCK-8) assay and colony formation assay, respectively. Cell metastasis was examined by Transwell assay and wound healing assay. Annexing-V/PI staining was employed to monitor cell apoptosis using flow cytometry. Levels of MAP3K2, proliferation- and apoptosis-related proteins were analyzed by Western blotting. Target interaction between miR-200a-3p and circBACH1 or MAP3K2 was confirmed by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. The role of circBACH1 in vivo was investigated by xenograft model assay.
Results
Expression of circBACH1 and MAP3K2 was increased, while miR-200a-3p expression was decreased in HCC tissues and HBV-transfected hepatoma cells. Depletion of circBACH1 or miR-200a-3p overexpression impeded HBV replication, proliferation, and metastasis in HBV-transfected hepatoma cells. CircBACH1 was able to regulate MAP3K2 expression by sponging miR-200a-3p. CircBACH1 regulated HBV replication and hepatoma progression through the miR-200a-3p/MAP3K2 pathway. Moreover, circBACH1 deficiency hampered tumor growth in vivo.