Preclinical characterization of therapeutic antibodies targeted at the carboxy-terminus of Sonic hedgehog

The Sonic Hedgehog (Shh) signaling pathway has been implicated in the development and tumor progression of a number of human cancers. Using synthetic peptide mimics to mount an immune response, we generated a mouse mAb to the carboxy (C)-terminus of the Shh protein and characterized its preclinical antitumor effects. In vitro screening guided selection of the best candidate for mAb scale-up production and therapeutic development. C-term anti-Shh, Ab 1C11-2G4 was selected based on ELISA screens, Western blotting, and flow cytometric analyses. Purified Ab 1C11-2G4 was shown to recognize and bind both Shh peptide mimics and cell surface Shh. Administration of Ab 1C11-2G4 not only reduced cell viability in 7 cancer cell lines but also significantly inhibitted tumor growth in a xenograft model of A549 lung cancer cells. Ex vivo analyses of xenograft tumors revealed a reduction in Shh signal transduction and apoptosis in 2G4-treated mice. Collectively, our results provide early demonstration of the antitumor utility of antibodies specific for the C-terminal region of Shh, and support continued development to evaluate their potential efficacy in cancers in which Shh activity is elevated.