Cyclopamine: From Cyclops Lambs to Cancer Treatment

In the late 1960s, the steroidal alkaloid cydopamine was isolated from the plant Veratrum californicum and identified as the teratogen responsible for craniofacial birth defects including cyclops in the offspring of sheep grazing on mountain ranges in the western United States. Cyclopamine was found to inhibit the hedgehog (Hh) signaling pathway, which plays a critical role in embryonic development. More recently, aberrant Rh signaling has been implicated in several types of cancer. Thus, inhibitors of the Rh signaling pathway, including cyclopamine derivatives, have been targeted as potential treatments for certain cancers and other diseases associated with the HI, signaling pathway. A brief history of cyclopamine and cyclopamine derivatives investigated for the treatment of cancer is presented.