APOBEC3G exerts tumor suppressive effects in human hepatocellular carcinoma.

In this study, we collected 44 hepatitis B virus surface antigen positivity HBsAg (+) tumor and nontumor hepatocellular tissues from hepatocellular carcinoma (HCC) patients during hepatectomy, and quantified the APOBEC3G (A3G) mRNA by using a real-time PCR. Our results showed higher expression of A3G mRNA in the nontumor tissues than in the tumor tissues of the HBsAg (+) HCC patients. To further investigate this phenomenon, we constructed a pLV-A3G vector and transfected it into the human HCC cell line, Hep 3B. The results of an immunofluorescence analysis showed the overexpression of A3G in the cytoplasm. We then evaluated A3G cytotoxicity by using a cell viability assay (MTS assay), the results of which showed that Hep 3B cell viability was 88 and 58% after the transfection of pLV and pLV-A3G, respectively, indicating the growth inhibitory effects of A3G on Hep 3B cells. To further evaluate the tumor suppressive effects of A3G, we used a plastic pipette tip to scratch Hep 3B cells grown on a culture dish (to 70-80% confluence) after transfection with pLV-A3G. Our data indicated a ratio of wound closure of 100% in the control cells and in the pLV-expressing cells, compared with 43% in the pLV-A3G-overexpressing cells, 72 h after the wound scratch, as observed using phase-contrast microscopy. These results indicated that A3G inhibits wound healing in Hep 3B cells. Overall, our results suggest that A3G inhibits the growth of human hepatoma cells.

APOBEC3B: a potential factor suppressing growth of human hepatocellular carcinoma cells.

BACKGROUND: To realize the role of apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like 3B (APOBEC3B) in hepatocellular carcinoma (HCC) occurrence, mRNAs of APOBEC3B from tumor and non-tumor tissues of patients with hepatectomy were isolated and in vitro studies were designed. MATERIALS AND METHODS: Seventy-two tumor and non-tumor tissue samples, as well as clinical data, were collected from HCC patients during hepatectomy. The mRNA of APOBEC3B was assessed by real-time polymerase chain reaction. The viability of pLV-APOBEC3B-transfected Hep 3B cells was then determined. Cell growth of pLV-APOBEC3B-transfected Hep 3B cells was evaluated by in vitro migration assay. RESULTS: The real-time polymerase chain reaction results indicated a higher expression of APOBEC3B mRNA in tumor tissues than in non-tumor tissues of patients with HBsAg+ HCC. The expression of APOBEC3B in tumor or non-tumor tissue was not found to be a risk factor of recurrence in patients with HCC. The cell viability assay results indicated the growth-inhibitory effects of APOBEC3B on Hep 3B cells. The cell migration results indicated that APOBEC3B inhibits wound healing in Hep 3B cells. CONCLUSION: Based on these observations, we infer that APOBEC3B is a potential factor contributing to suppression of tumor growth in HCC.