Cyclopamine inhibits activation of the Hedgehog response pathway by binding to and inhibiting the proto-oncogene Smoothened (SMO). The effects of oncogenic mutations that either activate SMO or inactivate the tumor suppressor Patched (Ptch) can be reversed by cyclopamine treatment. Cyclopamine has also been shown to induce apoptosis in colorectal adenoma cell lines, carcinoma-derived cell lines, and skin basal cell carcinomas and is being investigated as an anti-cancer drug.