Phytoestrogens derived from Belamcanda chinensis have an antiproliferative effect on prostate cancer cells in vitro.
OBJECTIVE
Phytoestrogens are nonsteroidal plant derived compounds with estrogenic activity that have been implicated in protecting against prostate cancer progression. We hypothesized that these compounds would alter cell number and increase the ability of antiandrogens to induce cell death in prostate cancer cells.


METHODS
RWPE-1, LNCaP and PC-3 cells were treated with or without an extract of Belamcanda chinensis, 2 purified phytoestrogens derived from this extract (irigenin and tectorigenin) and the antiandrogen bicalutamide. We assessed the effect on cell number, proliferation and apoptosis.


RESULTS
Phytoestrogens (50 to 100 microM) and bicalutamide (10 to 50 microM) alone decreased the cell number in all 3 cell lines. Phytoestrogens (50 microM) combined with bicalutamide (10 microM) further decreased the number of RWPE-1 and PC-3 cells compared to these agents alone. Tectorigenin and irigenin inhibited the proliferation of RWPE-1, LNCaP and PC-3 cells, causing G1 arrest and the induction of p21WAF1 or p27 protein expression, whereas bicalutamide induced apoptosis in a dose dependent manner in all 3 cell lines. Phytoestrogens did not have antiandrogenic activity.


CONCLUSIONS
These in vitro studies demonstrate a role for tectorigenin and irigenin in regulating prostate cancer cell number by inhibiting proliferation through cell cycle regulation.
Morrissey
Colm
C
Department of Surgery, Mater Misericordiae University Hospital, Conway Institute of Biomolecular and Biomedical Research, Dublin Molecular Medicine Centre, University College Dublin, Dublin, Ireland.
Bektic
Jasmin
J
Spengler
Barbara
B
Galvin
David
D
Christoffel
Volker
V
Klocker
Helmut
H
Fitzpatrick
John M
JM
Watson
R William G
RW
D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D004353:Drug Evaluation, Preclinical; D006801:Humans; D027621:Iridaceae; D007529:Isoflavones / Q000494:pharmacology / Q000627:therapeutic use*; D008297:Male; D048789:Phytoestrogens / Q000494:pharmacology / Q000627:therapeutic use*; D010936:Plant Extracts / Q000494:pharmacology / Q000627:therapeutic use*; D011471:Prostatic Neoplasms / Q000188:drug therapy* / Q000473:pathology*; D014407:Tumor Cells, Cultured
D007529:Isoflavones; D048789:Phytoestrogens; D010936:Plant Extracts; C509874:irigenin; C120039:tectorigenin