Ground glass hepatocytes co-express HBx and pre-S mutants and represent precursor lesions of HBV-related hepatocellular carcinoma: Implication for chemoprevention

[[abstract]]Ground glass hepatocytes (GGHs) represent a histologic hallmark of chronic hepatitis B virus (HBV) infection and harbor hepatitis B surface antigens. In the past years, we demonstrated that GGHs contain mutant pre-S1 or pre-S2 mutant proteins and represent precursor lesions of HBV-related hepatocellular carcinoma (HCC). The mutant pre-S proteins are accumulated in endoplasmic reticulum (ER) and initiate ER stress which cause oxidative DNA damage and genomic instability. Furthermore, the pre-S mutants can activate the Akt/mTOR signals through the VEGF-A pathway linked to ER stress. Besides ER stress-dependent signals, the pre-S2 mutants could additionally activate a signal pathway of JAB1/p27/RB/cyclins pathway, leading to cell proliferation. Patients with pre-S mutants in the serum or with clustered GGHs in the cirrhotic livers are high risk populations to develop HCC or to have recurrent tumor after surgery. In transgenic mice, both HBX and pre-S mutants can develop HCC but at different time points. The double-construct lines of HBx plus pre-S2 mutant can develop HCC at a much early stage. Interestingly, the transgenic mice livers revealed consistent fatty change at the early stage of tumorigenesis. By serial gene expression pro?les analyses, we found that the genes associated with in?ammation and lipid metabolism play an important role at the early and the tumor stages of HBV tumorigenesis. The activation of NFkB and mTOR/Akt signaling are activated in HBx transgenic livers and provide targets for chemoprevention of HCC. Since peroxisome proliferator activated receptors (PPARs) are involved in the regulation of metabolic syndrome through NFkB and in?ammation, we adopted natural products which exhibited high activities of PPAR-alpha and gamma, together with resveratrol (from grape skin), for the chemoprevention of HCC in HBx and pre-S2 mutant transgenic mice. In vitro, resveratrol and silymarin showed synergistic PPAR agonistic activities which can inhibit mTOR and Akt activities in Hep-G2 and Huh-7 cells. In vivo, preliminary studies in transgenic mice also observed dramatic effects of these products in the amelioration of fatty change and the reduction in the incidence of HCC formation. Therefore, these in vitro and in vivo studies provide supportive data for chemopreventive trials using natural products on patients with high risk to develop HCC or to relapse after HCC surgery