Small-molecule inhibition of Wnt signaling through activation of casein kinase
Small-molecule inhibition of Wnt signaling through activation of casein kinase 1α
Curtis A Thorne, Alison J Hanson, Judsen Schneider, Emilios Tahinci,
Darren Orton, Christopher S Cselenyi, Kristin K Jernigan, Kelly C Meyers,
Brian I Hang, Alex G Waterson, Kwangho Kim, Bruce Melancon, Victor P Ghidu, Gary A Sulikowski, Bonnie LaFleur, Adrian Salic, Laura A Lee, David M Miller III & Ethan Lee
Nature Chemical Biology 6 ,829–836 (2010)
doi:10.1038/nchembio.453
Received 06 May 2010
Accepted 08 September 2010
Published online 03 October 2010
Wnt/β-catenin signaling is critically involved in metazoan development, stem cell maintenance and human disease. Using Xenopus laevis egg extract to screen for compounds that both stabilize Axin and promote β-catenin turnover, we identified an FDA-approved drug, pyrvinium, as a potent inhibitor of Wnt signaling (EC50 of ∼10 nM). We show pyrvinium binds all casein kinase 1 (CK1) family members in vitro at low nanomolar concentrations and pyrvinium selectively potentiates casein kinase 1α (CK1α) kinase activity. CK1α knockdown abrogates the effects of pyrvinium on the Wnt pathway. In addition to its effects on Axin and β-catenin levels, pyrvinium promotes degradation of Pygopus, a Wnt transcriptional component. Pyrvinium treatment of colon cancer cells with mutation of the gene for adenomatous polyposis coli (APC) or β-catenin inhibits both Wnt signaling and proliferation. Our findings reveal allosteric activation of CK1α as an effective mechanism to inhibit Wnt signaling and highlight a new strategy for targeted therapeutics directed against the Wnt pathway.