Complex formation between heat shock protein 72 and hepatitis B virus X protein in hepatocellular carcinoma tissues

Hepatitis B virus (HBV) infection is a major factor contributing to the development of hepatocellular carcinoma (HCC) in the world. Hepatitis B virus X protein (HBx) has been verified to play an important role in hepatocarcinogenesis. Heat shock protein 72 (HSP72) as a molecular chaperone has been confirmed to overexpress in epithelial carcinoma cells. There may be a possible association between the expression of HSP72 and HBx during the growth and progression of hepatocellular carcinoma cells. The aim of the study was to investigate the relationship between heat shock protein 72 and HBx in human hepatocellular carcinomas. The localization of HSP72 and HBx in human hepatocellular carcinomas was determined by immunohistochemistry and confocal laser microscopy. The interaction between HSP72 and HBx in liver cancer cells was analyzed by immunoprecipitation and Western blot. Our results revealed that hepatocellular carcinoma synchronously co-expressed higher level of HSP72 and HBx than that in the adjacent tissues to hepatocellular carcinoma. HSP72 and HBx were mainly immunolocalized in the cytoplasm. On the basis of immunoprecipitation and Western blot, we found that HSP72 formed complex with HBx in human hepatocellular carcinoma cells. The association between HSP72 and HBx in human hepatocellular carcinoma cells may contribute to study the pathogenesis and immunotherapy of hepatocellular carcinoma.