Plant derived 3,3'-diindolylmethane is a strong androgen antagonist in human prostate cancer cells
Hien T. Le, Charlene M. Schaldach, Gary L. Firestone, and Leonard F. Bjeldanes
Nutritional Sciences and Toxicology, University of California at Berkeley, Berkekey, CA 94720
Corresponding Author:
lfb@nature.berkeley.edu
3,3’-Diindolylmethane (DIM), is a major digestive product of indole-3-carbinol (I3C), a potential anticancer component of cruciferous vegetables. Our results indicate that DIM exhibits potent antiproliferative and antiandrogenic properties in androgen dependent human prostate cancer cells. DIM suppresses cell proliferation of LNCaP cells and inhibits dihydrotestosterone (DHT) stimulation of DNA synthesis. These activities were not produced in androgen independent PC-3 cells. Moreover, DIM inhibited endogenous PSA transcription and reduced intracellular and secreted PSA protein levels induced by DHT in LNCaP cells. Also, DIM inhibited, in a concentration dependent manner, the DHT-induced expression of a PSA promoter regulated reporter gene construct in transiently transfected LNCaP cells. Similar effects of DIM were observed in PC-3 cells only when these cells were co-transfected with a wild type androgen receptor expression plasmid. Using fluorescence imaging with GFP-AR and Western blot analysis, we demonstrated that DIM inhibited androgen-induced AR translocation into the nucleus. Results of receptor binding assays indicated further that DIM is a strong competitive inhibitor of DHT binding to the AR. Results of structural modeling studies showed that DIM is remarkably similar in conformational geometry and surface charge distribution to an established synthetic AR antagonist although the atomic compositions of the two substances are quite different. Taken together with our published reports of the estrogen agonist activities of DIM, the present results establish DIM as a unique bifunctional hormone disrupter. To our knowledge, DIM is the first example of a pure androgen receptor antagonist from plants.
http://www.jbc.org/cgi/content/abstract/M300588200v1
It does have antiandrogen effect.