STAT3 deficiency prevents hepatocarcinogenesis and promotes biliary proliferation in thioacetamide-induced liver injury

AIM To elucidate the role of STAT3 in hepatocarcinogenesis and biliary ductular proliferation following chronic liver injury. METHODS We investigated thioacetamide(TAA)-induced liver injury, compensatory hepatocyte proliferation, and hepatocellular carcinoma(HCC) development in hepatic STAT3-deficient mice. In addition, we evaluated TAAinduced biliary ductular proliferation and analyzed the activation of sex determining region Y-box9(SOX9) and Yes-associated protein(YAP), which regulate the transdifferentiation of hepatocytes to cholangiocytes.RESULTS Both compensatory hepatocyte proliferation and HCC formation were significantly decreased in hepatic STAT3-deficient mice as compared with control mice. STAT3 deficiency resulted in augmentation of hepatic necrosis and fibrosis. On the other hand, biliary ductular proliferation increased in hepatic STAT3-deficient livers as compared with control livers. SOX9 and YAP were upregulated in hepatic STAT3-deficient hepatocytes.CONCLUSION STAT3 may regulate hepatocyte proliferation as well as transdifferentiation into cholangiocytes and serve as a therapeutic target for HCC inhibition and biliary regeneration.

Tumor-derived insulin-like growth factor-binding protein-1 contributes to resistance of hepatocellular carcinoma to tyrosine kinase inhibitors

Background:Antiangiogenic tyrosine kinase inhibitors(TKIs)provide one of the few therapeutic options for effective treatment of hepatocellular carcinoma(HCC).However,patients with HCC often develop resistance toward antiangiogenic TKIs,and the underlying mechanisms are not understood.The aim of this study was to determine the mechanisms underlying antiangiogenic TKI resistance in HCC.Methods:We used an unbiased proteomic approach to define proteins that were responsible for the resistance to antiangiogenic TKIs in HCC patients.We evaluated the prognosis,therapeutic response,and serum insulin-like growth factor-binding protein-1(IGFBP-1)levels of 31 lenvatinib-treated HCC patients.Based on the array of results,a retrospective clinical study and preclinical experiments using mouse and human hepatoma cells were conducted.Additionally,in vivo genetic and pharmacological gain-and loss-of-function experiments were performed.Results:In the patient cohort,IGFBP-1 was identified as the signaling molecule with the highest expression that was inversely associated with overall survival.Mechanistically,antiangiogenic TKI treatment markedly elevated tumor IGFBP-1 levels via the hypoxia-hypoxia inducible factor signaling.IGFBP-1 stimulated angiogenesis through activation of the integrinα5β1-focal adhesion kinase pathway.Consequently,loss of IGFBP-1 and integrinα5β1 by genetic and pharmacological approaches re-sensitized HCC to lenvatinib treatment.Conclusions:Together,our data shed light onmechanisms underlying acquired resistance of HCC to antiangiogenic TKIs.Antiangiogenic TKIs induced an increase of tumor IGFBP-1,which promoted angiogenesis through activating the IGFBP-1-integrinα5β1 pathway.These data bolster the application of a new therapeutic concept by combining antiangiogenic TKIs with IGFBP-1 inhibitors.