Cancer Therapy: Preclinical Wnt-Pathway Activation in Two Molecular Classes of Hepatocellular Carcinoma and Experimental Modulation by Sorafenib

Purpose: Hepatocellular carcinoma (HCC) is a heterogeneous cancer with active Wnt signaling. Underlying biologic mechanisms remain unclear and no drug targeting this pathway has been approved todate.Weaimed to characterizeWnt-pathway aberrations inHCCpatients, and to investigate sorafenib as a potential Wnt modulator in experimental models of liver cancer. Experimental Design: The Wnt-pathway was assessed using mRNA (642 HCCs and 21 liver cancer cell lines) and miRNA expression data (89 HCCs), immunohistochemistry (108 HCCs), and CTNNB1mutation data (91 HCCs). Effects of sorafenib on Wnt signaling were evaluated in four liver cancer cell lines with active Wnt signaling and a tumor xenograft model. Results: Evidence for Wnt activation was observed for 315 (49.1%) cases, and was further classified as CTNNB1 class (138 cases [21.5%]) orWnt-TGFb class (177 cases [27.6%]). CTNNB1 classwas characterized by upregulation of liver-specific Wnt-targets, nuclear b-catenin and glutamine-synthetase immunostaining, and enrichment of CTNNB1-mutation-signature, whereas Wnt-TGFb class was characterized by dysregulation of classical Wnt-targets and the absence of nuclear b-catenin. Sorafenib decreased Wnt signaling and b-catenin protein in HepG2 (CTNNB1 class), SNU387 (Wnt-TGFb class), SNU398 (CTNNB1-mutation), and Huh7 (lithium-chloride-pathway activation) cell lines. In addition, sorafenib attenuated expression of liver-related Wnt-targets GLUL, LGR5, and TBX3. The suppressive effect on CTNNB1 class–specific Wntpathway activation was validated in vivo using HepG2 xenografts in nude mice, accompanied by decreased tumor volume and increased survival of treated animals. Conclusions:Distinct dysregulation ofWnt-pathway constituents characterize two differentWnt-related molecular classes (CTNNB1 and Wnt-TGFb), accounting for half of all HCC patients. Sorafenib modulates b-catenin/Wnt signaling in experimental models that harbor the CTNNB1 class signature. Clin Cancer Res; 18(18); 4997–5007. 2012 AACR.