Hepatitis C virus–induced tumor-initiating cancer stem–like cells activate stromal fibroblasts in a xenograft tumor model

Abstract

Hepatitis C virus (HCV) often causes persistent infection and is an increasingly important factor in the etiology of fibrosis/cirrhosis and hepatocellular carcinoma, although the mechanisms for the disease processes remain unclear. We have shown previously that HCV infection generates an epithelial–mesenchymal transition state and tumor-initiating cancer stem–like cells in human hepatocytes. In this study, we investigated whether HCV-induced tumor-initiating cancer stem–like cells when implanted into mice activate stromal fibroblasts. A number of fibroblast activation markers, including matrix metalloproteinase 2, were significantly increased at the mRNA or protein level in the xenograft tumors, suggesting the presence of tumor-associated fibroblasts. Fibroblast activation markers of murine origin were specifically increased in tumor, suggesting that fibroblasts migrate to form stroma. Next, we demonstrated that conditioned medium from HCV-infected human hepatocytes activates fibrosis-related markers in hepatic stellate cells. We further observed that these HCV-infected hepatocytes express transforming growth factor beta, which activates stromal fibroblast markers. Subsequent analysis suggested that anti–transforming growth factor beta neutralizing antibody, when incubated with conditioned medium from HCV-infected hepatocytes, inhibits fibrosis marker activation in primary human hepatic stellate cells. Conclusion: HCV-infected hepatocytes induce local fibroblast activation by secretion of transforming growth factor beta, and a preneoplastic or tumor state of the hepatocytes influences the network for the tumor-associated fibroblast environment. (Hepatology 2017;66:1766–1778).