Resveratrol is reported to possess chemotherapeutic properties in several cancers. In this study, we wanted to investigate the molecular mechanisms of resveratrol-induced cell cycle arrest and apoptosis as well as the impact of resveratrol on NAMPT and SIRT1 protein function and asked whether there are differences in hepatocarcinoma cells (HepG2, Hep3B cells) and non-cancerous primary human hepatocytes. We found a lower basal NAMPT mRNA and protein expression in hepatocarcinoma cells compared to primary hepatocytes. In contrast, SIRT1 was significantly higher expressed in hepatocarcinoma cells than in primary hepatocytes. Resveratrol induced cell cycle arrest in the S- and G2/M- phase and apoptosis was mediated by activation of p53 and caspase-3 in HepG2 cells. In contrast to primary hepatocytes, resveratrol treated HepG2 cells showed a reduction of NAMPT enzymatic activity and increased p53 acetylation (K382). Resveratrol induced NAMPT release from HepG2 cells which was associated with increased NAMPT mRNA expression. This effect was absent in primary hepatocytes where resveratrol was shown to function as NAMPT and SIRT1 activator. SIRT1 inhibition by EX527 resembled resveratrol effects on HepG2 cells. Furthermore, a SIRT1 overexpression significantly decreased both p53 hyperacetylation and resveratrol-induced NAMPT release as well as S-phase arrest in HepG2 cells. We could show that NAMPT and SIRT1 are differentially regulated by resveratrol in hepatocarcinoma cells and primary hepatocytes and that resveratrol did not act as a SIRT1 activator in hepatocarcinoma cells.

Liver disease is now a leading cause of non-AIDS related morbidity and mortality in people living with HIV (PLWH). The present study investigated the interplay between adverse lifestyle factors that are prevalent in PLWH, biological mediators of liver pathogenesis, and a non-invasive measure of liver fibrosis (FIB-4 index) in HIV mono- and HIV/HCV co-infected individuals. The results of this investigation in the Miami Adult Studies of HIV (MASH) cohort show that the odds of liver fibrosis progression significantly increased over two years for HIV mono-infected participants who drank alcohol hazardously (OR 3.038, P=0.048), and had BMI ≥ 28kg/m2 (OR 2.934, P=0.027). Cocaine use reduced the odds of advancing one stage of liver fibrosis (OR 0.228, P=0.038), but an interaction between high BMI and cocaine use slightly raised the odds by 4.8% of liver fibrosis progression (P=0.072). HIV/HCV co-infected participants showed interactions between cocaine use and high BMI with increased FIB-4 stage (OR 4.985, P= 0.034), however no lifestyle factors could independently predict FIB-4 stage in this group. Biological mediators previously associated with liver pathogenesis were associated with higher FIB-4 index over 2 years in a subset of (n=65) HIV mono-infected participants. Plasma measures of oxidative stress (% oxidized glutathione: OR 4.342, P= 0.046), hepatocyte-specific apoptosis (Cytokeratin-18 (CK-18): OR 1.008, P=0.021), and microbial endotoxin (lipopolysaccharide (LPS): OR 1.098, P= 0.097) were associated with having higher odds of progressing at least one stage of FIB-4 over 2 years. The same biological mediators were also associated with liver fibrosis within HIV infected people who also had a harmful lifestyle characteristic. FIB-4 index was significantly associated with % oxidized glutathione in obese subjects (β=0.563, P=0.018), TGF-β1 in cocaine users (β=0.858, P=0.027), and CK-18 in HIV infected individuals without any adverse lifestyle factors (β=0.435, P=0.015). Taken together, the findings of these studies describe interrelationships between HIV disease status, lifestyle, and biological mediators of liver fibrosis. The results show interactions between lifestyle conditions and the mediators of liver fibrosis may account for higher rates of liver disease in HIV infection. Research is warranted to develop personalized therapeutics for PLWH to curb the burden of liver disease.