Circ_0027089 regulates NACC1 by targeting miR-136-5p to aggravate the development of hepatitis B virus-related hepatocellular carcinoma

Hepatitis B virus (HBV) infection is the main trigger of hepatocellular carcinoma (HCC). Circular RNA plays an indispensable role in cancer development, and this study aimed to disclose the function and mechanism of circ_0027089 in HBV-related HCC. The expression levels of circ_0027089, miR-136-5p and nucleus accumbens associated protein 1 (NACC1) mRNA were measured by quantitative real-time PCR, and the protein level of NACC1 was detected by western blot. For functional analyses, cell proliferation was assessed by cell counting kit-8 assay and colony formation assay. Cell apoptosis and cell cycle were detected by flow cytometry assay, and cell apoptosis was also assessed by caspase 3/7 activity. The capacities of migration and invasion were evaluated by wound healing assay and transwell assay, respectively. The predicted relationship between miR-136-5p and circ_0027089 or NACC1 was validated by dual-luciferase reporter assay and RNA binding protein immunoprecipitation assay. Animal experiments were performed in nude mice to explore the role of circ_0027089 in vivo. Circ_0027089 expression and NACC1 expression were elevated, while miR-136-5p expression was decreased in HBV-related HCC tissues and cells. In function, circ_0027089 knockdown inhibited HepG2.2.15 and HepAD38 (tet-off) cell proliferation, migration and invasion but induced cell cycle arrest and apoptosis, while circ_0027089 overexpression played the reversed effects. For mechanism exploration, miR-136-5p was a target of circ_0027089, and miR-136-5p deficiency could reverse the role of circ_0027089 knockdown. Circ_0027089 functioned as an oncogene to promote the development of HBV-related HCC by regulating NACC1 via competitively targeting miR-136-5p.