Sorafenib is the first approved targeted therapeutic reagent for hepatocellular carcinoma (HCC). Here, we report that Src homology region 2 (SH2) domain-containing phosphatase 1 (SHP-1) is a major target of sorafenib and generates a series of sorafenib derivatives to search for potent SHP-1 agonists that may act as better anti-HCC agents than sorafenib. Sorafenib increases SHP-1 activity by direct interaction and impairs the association between the N-SH2 domain and the catalytic protein tyrosine phosphatase domain of SHP-1. Deletion of the N-SH2 domain (dN1) or point mutation (D61A) of SHP-1 abolished the effect of sorafenib on SHP-1, phosphorylated signal transducer and activator of transcription 3 (p-STAT3), and apoptosis, suggesting that sorafenib may affect SHP-1 by triggering a conformational switch relieving its autoinhibition. Molecular docking of SHP-1/sorafenib complex confirmed our findings in HCC cells. Furthermore, novel sorafenib derivatives SC-43 and SC-40 displayed more potent anti-HCC activity than sorafenib, as measured by enhanced SHP-1 activity, inhibition of p-STAT3, and induction of apoptosis. SC-43 induced substantial apoptosis in sorafenib-resistant cells and showed better survival benefits than sorafenib in orthotopic HCC tumors.
Conclusion: In this study, we identified SHP-1 as a major target of sorafenib. SC-43 and SC-40, potent SHP-1 agonists, showed better anti-HCC effects than sorafenib in vitro and in vivo. Further clinical investigation is warranted.
© 2013 by the American Association for the Study of Liver Diseases.