Cyclopamine is a natural steroidal alkaloid that inhibits signaling through the hedgehog pathway at the level of the pathway activator Smoothened. By altering gene expression in this signaling sequence, cyclopamine induces defects in morphogenesis, first observed in chicks and sheep as cyclopia. As a readout of action, cyclopamine inhibits hedgehog-dependent expression of Pax7 with an IC50 value of 24 nM. Although teratogenic during development, cyclopamine has potential applications in the treatment of cancer.
