Background:

Cyclopamine is a naturally occurring Hedgehog (Hh)?specific small?molecule signaling steroidal alkaloid inhibitor, causes a profound inhibition of tumor growth, has significant anti?invasive, anti?proliferative and anti?estrogenic potency in human breast cancer cells [2] [1]. The EC50 of cyclopamine is 10.57 μM, it was identified by an FXR-bla (farnesoid X receptor- b-lactamase) assay [3].

Hh signaling pathway plays a critical role in embryonic development and tumorigenesis [4]. Hh signaling pathway shows saliency in regulating cellular proliferation and differentiation in a wide array of human tissues. It is related to aberrant cell survival in numerous human malignancies, ranging from BCCs and medulloblastomas to small cell lung, gastrointestinal, breast and prostate tumors [1].

Treated with cyclopamine (10 or 20 μM) only and incubated for time periods ranging from 0 to10 days, MCF-7 cells and MDA?MB?231 cells displayed a significant reduction in proliferation rate compared with the control cells on days 3 and 6 (P<0.01). In the MCF?7 cells, cyclopamine significantly induced cell accumulation in the G1 phase (P<0.01) and a modest decrease in the S population percentage, from 22 to 16% (P<0.01). In the MDA?MB?231 cells, cyclopamine caused a significant increase in G1 cells. The invasion rate of cyclopamine?treated MCF?7 and MDA?MB?231cells significantly decreased compared with the CK [2].

Embryoes exposed to cyclopamine resulted in visible external defects, including cyclopia, proboscis formation, microphthalmia, thoracic lordosis, amelia and decreased body size. Examination of gastrointestinal organs revealed severe deficits, including less length of the gut tube and mesenchymal cell numbers in foregut-derived organs. Ectopic structures in duodenum, stomach, and dorsal pancreas were also found [5].

参考文献:
[1].  Marc J. Meth and Jeffrey M. Weinberg. Cyclopamine: Inhibiting Hedgehog in the Treatment of Psoriasis. Continuing Medical Education, 2006, 78: 185-188.
[2].  Jun Che, Fu-Zheng Zhang, Chao-Qian Zhao, et al. Cyclopamine is a novel Hedgehog signaling inhibitor with significant anti?proliferative, anti?invasive and anti?estrogenic potency in human breast cancer cells. Oncology Letters, 2013, 5: 1417-1421.
[3].  Chia-Wen Hsu, Jinghua Zhao, Ruili Huang, et al. Quantitative High-Throughput Profiling of Environmental Chemicals and Drugs that Modulate Farnesoid X Receptor. Scientific Reports, 2014, 4: 6437.
[4].  Robert J. Lipinski, Paul R. Hutson, Paul W. Hannam, et al. Dose- and Route-Dependent Teratogenicity, Toxicity, and Pharmacokinetic Profiles of the Hedgehog Signaling Antagonist Cyclopamine in the Mouse. Toxicological Sciences, 2008, 104(1):189-197.
[5].  Seung K. Kim and Douglas A. Melton. Pancreas development is promoted by cyclopamine, a Hedgehog signaling inhibitor. Proc. Natl. Acad. Sci. USA, 1998, 95: 13036-13041.