Inhibition of extracellular signal-regulated kinase 1 by adenovirus mediated small interfering RNA attenuates hepatic fibrosis in rats.

UNLABELLED: Extracellular signal-regulated kinase 1 (ERK1) is a critical part of the mitogen-activated protein kinase signal transduction pathway, which is involved in hepatic fibrosis. However, the effect of down-regulation of ERK1 on hepatic fibrosis has not been reported. Here, we induced hepatic fibrosis in rats with dimethylnitrosamine administration or bile duct ligation. An adenovirus carrying small interfering RNA targeting ERK1 (AdshERK1) was constructed to determine its effect on hepatic fibrosis, as evaluated by histological and immunohistochemical examination. Our results demonstrated that AdshERK1 significantly reduced the expression of ERK1 and suppressed proliferation and levels of fibrosis-related genes in hepatic stellate cells in vitro. More importantly, selective inhibition of ERK1 remarkably attenuated the deposition of the extracellular matrix in fibrotic liver in both fibrosis models. In addition, both hepatocytes and biliary epithelial cells were proven to exert the ability to generate the myofibroblasts depending on the insults of the liver, which were remarkably reduced by AdshERK1. Furthermore, up-regulation of ERK1 paralleled the increased expression of transforming growth factor beta1 (TGF-beta1), vimentin, snail, platelet-derived growth factor-BB (PDGF-BB), bone morphogenetic protein 4 (BMP4), and small mothers against decapentaplegic-1 (p-Smad1), and was in reverse correlation with E-cadherin in the fibrotic liver. Nevertheless, inhibition of ERK1 resulted in the increased level of E-cadherin in parallel with suppression of TGF-beta1, vimentin, snail, PDGF-BB, BMP4, and p-Smad1. Interestingly, AdshERK1 treatment promoted hepatocellular proliferation. CONCLUSION: Our study provides the first evidence for AdshERK1 suppression of hepatic fibrosis through the reversal of epithelial-mesenchymal transition of both hepatocytes and biliary epithelial cells without interference of hepatocellular proliferation. This suggests that ERK1 is implicated in hepatic fibrogenesis and selective inhibition of ERK1 by small interfering RNA may present a novel option for hepatic fibrosis treatment.

[Genetic analysis of HAV strains isolated from patients with acute hepatitis in Hebei Shijiazhuang of China].

OBJECTIVE: To characterize the hepatitis A virus (HAV) wild type strains circulating in Hebei Shijiazhuang of China during 2005-2007, to provide the bases for further investigation of the sources of HAV infection. METHODS: The VP1/P2A junction regions were detected by RT-PCR from HAV IgM positives serum samples during 2005 and 2007, the 34 RT-PCR positive samples were sequenced and subjected to phylogenetic analysis by Neighbor Joining (NJ) method. RESULTS: All the detected HAV strains were identified as sub-genotype I A, the homology of nucleotide sequence in the VP1-2A imation region ranged from 95%-100%, the amino acid sequences of HAV strains almost had no difference. CONCLUSION: There are different HAV strains existing in Hebei Shijiazhuang of China, same HAV strain may exist in different areas; or in one area, identical or different HAV strains may be detected. This work provides the bases for further investigation of the sources of HAV infection and also for effectively control measures to prevent the spread of the disease.

Differentiation therapy of hepatocellular carcinoma in mice with recombinant adenovirus carrying hepatocyte nuclear factor-4alpha gene.

UNLABELLED: Previous studies have shown that hepatocyte nuclear factor-4alpha (HNF4alpha) is a central regulator of differentiated hepatocyte phenotype and forced expression of HNF4alpha could promote reversion of tumors toward a less invasive phenotype. However, the effect of HNF4alpha on cancer stem cells (CSCs) and the treatment of hepatocellular carcinoma (HCC) with HNF4alpha have not been reported. In this study, an adenovirus-mediated gene delivery system, which could efficiently transfer and express HNF4alpha, was generated to determine its effect on hepatoma cells (Hep3B and HepG2) in vitro and investigate the anti-tumor effect of HNF4alpha in mice. Our results demonstrated that forced re-expression of HNF4alpha induced the differentiation of hepatoma cells into hepatocytes, dramatically decreased "stemness" gene expression and the percentage of CD133(+) and CD90(+) cells, which are considered as cancer stem cells in HCC. Meanwhile, HNF4alpha reduced cell viability through inducing apparent apoptosis in Hep3B, while it induced cell cycle arrest and cellular senescence in HepG2. Moreover, infection of hepatoma cells by HNF4alpha abolished their tumorigenesis in mice. Most interestingly, systemic administration of adenovirus carrying the HNF4alpha gene protected mice from liver metastatic tumor formation, and intratumoral injection of HNF4alpha also displayed significant antitumor effects on transplanted tumor models. CONCLUSION: The striking suppression effect of HNF4alpha on tumorigenesis and tumor development is attained by inducing the differentiation of hepatoma cells--especially CSCs--into mature hepatocytes, suggesting that differentiation therapy with HNF4alpha may be an effective treatment for HCC patients. Our study also implies that differentiation therapy may present as one of the best strategies for cancer treatment through the induction of cell differentiation by key transcription factors.