Expression of HBx and COX-2 in chronic hepatitis B, cirrhosis and hepatocellular carcinoma: implication of HBx in upregulation of COX-2.

Hepatitis B virus is a major etiological factor of hepatocellular carcinoma, but the underlying mechanisms remain unclear. We have previously demonstrated that upregulation of cyclooxygenase (COX)-2 in chronic hepatitis B persisted despite successful antiviral therapy. In this study, we investigated the relationship between the transactivator HBx and COX-2 in hepatitis B virus-associated chronic liver diseases. Expressions of HBx and COX-2 in tissue specimens were determined by single and double immunohistochemistry. The effects of HBx on COX-2 and prostaglandin E2 production were studied by transfection. HBx was expressed in 11/11 (100%) of chronic hepatitis B, 23/23 (100%) of cirrhosis, and 18/23 (78%) of hepatocellular carcinoma, whereas no immunoreactivity was found in four nonalcoholic steato-hepatitis controls. COX-2 expression was also detected in all specimens of liver lesions except in only 29% of poorly differentiated hepatocellular carcinoma. Significant correlation between HBx and COX-2 immunoreactivity scores was found in different types of chronic liver diseases (chronic hepatitis B, rs = 0.68; cirrhosis, rs = 0.57; hepatocellular carcinoma, rs = 0.45). Double immunohistochemistry showed colocalization of HBx and COX-2 in hepatic parenchymal cells. Similar to COX-2, there was no significant change in HBx expression in patients with chronic hepatitis B after interferon and lamivudine therapy when hepatitis B virus DNA became undetectable and inflammation subsided. Transfection of Hep3B hepatocellular carcinoma cells with HBx increased COX-2 expression and prostaglandin E2 production. HBx was localized mainly in the cytoplasm and less in nucleus, as found in the liver lesions. In conclusion, our results strongly suggested that there was a close relationship between HBx and COX-2. COX-2 might represent an important cellular effector of HBx that contributes to hepatitis B virus-associated hepatocarcinogenesis.

Cyclooxygenase-2 pathway correlates with vascular endothelial growth factor expression and tumor angiogenesis in hepatitis B virus-associated hepatocellular carcinoma.

Evidence indicates that cyclooxygenase (COX)-2-derived prostaglandins (PGs) contribute to tumor growth by inducing angiogenesis. We investigated the role of COX-2 in hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC). COX-2 and vascular endothelial growth factor (VEGF) expressions were examined by immunohistochemistry in 24 HBV-associated HCC. Tumor micro-vessel density (MVD) was assessed using CD34 immunohistochemistry. Hep3B HCC cell line, which carries integrated HBV genome, was stably transfected with human COX-2 cDNA. COX-2 and VEGF expressions were determined by Western blot while PG level was determined by ELISA. The effects of PGs on VEGF expression were also investigated. Expression of COX-2 and VEGF in HCC cells were observed in 19 (79%) and 16 (67%) cases, respectively. Well-differentiated HCC expressed COX-2 more strongly than less-differentiated HCC (p<0.001). COX-2 expression was found to correlate with VEGF expression and MVD (p=0.003 and 0.004, respectively). COX-2 overexpressing Hep3B clone had higher VEGF expression as compared to non-COX-2 expressing clone and parental cells. Treatment of the COX-2 overexpressing cells with a COX-2-selective inhibitor, NS-398 (10 microM), decreased PGE2 level and attenuated VEGF expression. Addition of PGE2 (10 microM) and the stable analog of PGI2, carbaprostacyclin (5 microM), to Hep3B cells also increased VEGF expression. Up-regulation of COX-2 correlates with VEGF expression and tumor angiogenesis in HBV-associated HCC. Moreover, COX-2 up-regulates VEGF expression in HCC cells, possibly via PGs production. Selective inhibition of COX-2 may block HCC associated angiogenesis and thus provides a rational approach for treatment of this malignancy.

Combination of a new composite biocampatible skin graft on the neodermis of artificial skin in an animal model.

INTRODUCTION: There have been very limited and inconsistent attempts at combining the cultured epidermal autograft (CEA) with the neodermis of artificial skin (Integra). The reasons for this remain unknown. The basement membrane proteins of conventional CEA sheets are easily damaged by the dispase treatment during the harvesting of the CEA from the culture flask. The damage of the basement membrane proteins may affect the anchorage of CEA onto the neodermis of Integra. A new Composite Biocompatible Skin Graft (CBSG) was recently developed. METHODS: Composite biocompatible skin graft consists of autologous keratinocytes cultivated on a pliable hyaluronate-derived membrane (Laserskin)which has been pre-seeded with allogenic dermal fibroblasts. Basement membrane proteins of CBSG are protected from the dispase treatment because the keratinocytes are directly seeded onto Laserskin. The engraftment of CBSG was evaluated on 20 wounds of 10 rats. Integrawas grafted on two freshly excised full-thickness wounds (3cm in diameter) in the dorsum of each animal. A polypropylene ring was applied to each wound to prevent the migration of epithelium from the edges. Composite Biocompatible Skin Graft was used to cover the neodermis of Integra after the silicone membrane was removed 14-21 days postgrafting. RESULTS: Fourteen (70%) of 20 skin biopsies taken at day 21 from the centre of the grafted wounds revealed regenerated epithelium. CONCLUSION: A feasible delivery system of cultured keratinocytes onto theneodermis of Integra is demonstrated in this animal -experiment.