01.09 Inhibition of ECM Protein Expression in Hepatic Stellate Cells by JHC0123, an Inhibitor of STAT3

F. J. Bohanon¹, X. Wang¹, O. A. Nunez Lopez¹, A. Kandathiparampil¹, N. Ye¹, S. J. Vasudevan¹, H. Chen¹, J. Zhou¹, R. S. Radhakrishnan^{1 1}University Of Texas Medical Branch,Galveston, TX, USA

Introduction: STAT3 plays an important role in many physiologic and pathologic processes by regulating cell proliferation, differentiation, and metabolism. It has been reported that the STAT3 pathway is involved in hepatic fibrogenesis. Activated hepatic stellate cells (HSC) are the major effector cells for liver fibrosis, and HSC activation is characterized by increased proliferation and over-expression of α-smooth muscle actin, and extracellular matrix (ECM) proteins. Recently, our team developed a series of novel small-molecule inhibitors of STAT3 and demonstrated their potent anti-tumor effects in breast cancer cells. In the present study, we tested their anti-fibrogenic effects using activated HSC.

Methods: The proliferation of activated human and rat HSC cell lines LX-2 and HSC-T6 were measured by Alamar Blue. Cellular proteins were determined by Western blots and immunofluorescence. Flow cytometry was conducted for cell cycle study. Yo-pro-1 staining was used for apoptosis.

Results:HJC0123 treatment significantly inhibited LX-2 and HSC-T6 cell growth and attenuated HSC activation marker α-smooth muscle actin expression. The expression of endogenous ECM collagen type I and fibronectin was suppressed by HJC0123 in a dose- and time-dependent manner. TGFβ has been identified as the most potent stimulator for ECM. Our data show that in LX-2 cells, TGFβ significantly up-regulated collagen type I and fibronectin expression, and pretreatment with HJC0123 prevented TGFβ-stimulated ECM production. Furthermore, pretreatment with HJC0123 impaired TGFβ-induced pSmad2/3 expression and nuclear translocation, indicating that the TGFβ/pSmad pathway plays a role in ECM regulation by HJC0123.

Conclusion:HJC0123 inhibits HSC proliferation, suppresses endogenous and TGFβ-induced ECMs expression. HJC0123 is a promising anti-hepatic fibrogenic agent.