Phytoestrogens from Belamcanda chinensis regulate the expression of steroid receptors and related cofactors in LNCaP prostate cancer cells.
OBJECTIVE
To investigate the changes in expression underlying the marked reduction of tumour growth in vivo, by analysing the effect of Belamcanda chinensis extract (BCE) on LNCaP cells in vitro, as phytoestrogens are chemopreventive in prostate cancer, and in previous studies we examined the effects of the isoflavone tectorigenin isolated from B. chinensis on LNCaP prostate cancer cells, and a BCE consisting of 13 phytoestrogenic compounds on tumour-bearing nude mice.


METHODS
LNCaP cells were treated with 100, 400 or 1400 microg/mL BCE; proliferation was assessed with an Alamar Blue assay. We used real-time reverse transcription-polymerase chain reaction to quantify mRNA expression of the androgen receptor (AR), the AR coactivator prostate derived Ets transcription factor (PDEF), NKX3.1, prostate specific antigen (PSA) and oestrogen receptor-beta (ER-beta) compared with the expression of the housekeeping gene porphobilinogen deaminase (PBGD). PSA secretion from LNCaP cells was measured and protein expression of the AR investigated by Western blot analysis.


RESULTS
Concomitant with a marked decrease of tumour cell proliferation BCE down-regulated the expression of the AR, PDEF, NKX3.1 and PSA. In the same experiments, the expression of PBGD was unaltered, whereas ER-beta expression increased. Furthermore, AR protein and PSA secretion were markedly diminished after treatments with the BCE.


CONCLUSIONS
BCE, comprising 13 different phytoestrogens, decreases the expression of the AR and its co-activator PDEF concomitant with diminished cell proliferation and PSA secretion. NKX3.1 expression was also reduced by BCE. We hypothesise that the positive effects of BCE are initiated by up-regulation of the ER-beta, a putative tumour-suppressor gene.
Thelen
Paul
P
Department of Urology, Georg-August-University, Göttingen, Germany. pthelen@gwdg.de
Peter
Thomas
T
Hünermund
Anika
A
Kaulfuss
Silke
S
Seidlová-Wuttke
Dana
D
Wuttke
Wolfgang
W
Ringert
Rolf-Hermann
RH
Seseke
Florian
F
D000818:Animals; D015153:Blotting, Western; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D006801:Humans; D027621:Iridaceae / Q000737:chemistry*; D008297:Male; D051379:Mice; D008819:Mice, Nude; D048789:Phytoestrogens / Q000494:pharmacology*; D010936:Plant Extracts / Q000494:pharmacology; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000378:metabolism*; D012333:RNA, Messenger; D011944:Receptors, Androgen / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured
D048789:Phytoestrogens; D010936:Plant Extracts; D012333:RNA, Messenger; D011944:Receptors, Androgen; D017430:Prostate-Specific Antigen