Byssochlamysol, a new antitumor steroid against IGF-1-dependent cells from Byssochlamys nivea. I. Taxonomy, fermentation, isolation and biological activity.

A new antitumor steroid, byssochlamysol, was isolated from the mycelium of Byssochlamys nivea M#5187. Byssochlamysol inhibited IGF-1-dependent growth of MCF-7 human breast cancer cells with an IC50 of 20 ng/ml, whereas serum-dependent cell growth was not inhibited by less than 10 microg/ml of byssochlamysol. This substance induced apoptosis in IGF-1-dependent Colo320DM human colon cancer cells.