HPI-4 is a Hedgehog pathway inhibitor and ciliogenesis inhibitor. The Hedgehog (HH) signaling pathway is targeted for anti-cancer therapeutics and HPI-4 blocks Sonic hedgehog (Shh)-induced hedgehog pathway activation (IC50 = 7 μM) downstream of Smo. It also inhibits cytoplasmic AAA+ ATPase dynein-dependent microtubule gliding and ATPase activity.
1. Hyman, Joel M., et al., 2009. Small-molecule inhibitors reveal multiple strategies for Hedgehog pathway blockade. Proceedings of the National Academy of Sciences of the United States of America. 106(33): 14132-7. PMID: 19666565