Abstract:Objective：To investigate the effect and mechanism of cyclopamine，the inhibitor of Sonic hedgehog signaling pathway, on the proliferation and apoptosis of pancreatic cancer cell line SUIT-2. Methods：The SUIT-2 cells used in the experiment were cultured in vitro，and the MTT assay was used to examine the antiproliferative effect of cyclopamine. Flow cytometry(FCM) was used to examine the effects of cyclopamine on the proliferation index(PI) and apoptosis index(AI) of SUIT-2 cells. Nude mice tumor graft model was used to determine the effect of cyclopamine on growth inhibition of tumor graft.Results：Cyclopamine produced time and concentration dependent antiproliferative effects on SUIT-2 cells. Cyclopamine could induce apoptosis and block cell cycle at G0／G1 phase. In cyclopamin treated SUIT-2 cells, the apoptosis index(AI) was 14.3±0.35, and proliferation index(PI) was 36.1±0.44; and in control group, the AI was 1.3±0.24, the PI was 52.3±0.28(all P<0.05）．In the nude mice model, cyclopamine produced apparent antiproliferative effect in concurrent treatment group, but had weaker effect in delayed treatment group. Conclusions：shh signaling pathway is essential for the maintaining of pancreatic cancer cell proliferation. Blocking shh pathway can inhibit the growth of pancreatic cancer cell and induce apoptosis.