Genistein induces cell growth inhibition in prostate cancer through the suppression of telomerase activity.
OBJECTIVE
To clarify the mechanism of the anticancer effect of genistein, we examined the effect of genistein on telomerase activity in prostate cancer cells. We hypothesized that genistein may exert its anticancer effect by modifying telomerase activity in prostate cancer cells.


METHODS
Prostate cancer (LNCaP) cells were cultured with genistein and the number of viable cells was counted. Growth medium was also collected to measure prostate-specific antigen (PSA) concentration. Polymerase chain reaction (PCR)-based telomeric repeat amplification protocol (TRAP) assay and reverse transcriptase (RT)-PCR analysis were performed to investigate telomerase activity and the expression of human telomerase reverse transcriptase (hTERT), c-myc and p21 mRNA. To examine the possibility that hTERT transcriptional activity is modulated by genistein, transient cell transfection studies were performed by using luciferase reporter assay. Telomere repeat amplification protocol (TRAP) assay and PCR analysis of hTERT were performed in androgen independent cells, DU-145.


RESULTS
Cell growth of LNCaP was inhibited by genistein and PSA secretion was similarly reduced. In TRAP assay, the telomerase activity of LNCaP cells was reduced by genistein. Reverse transcriptase-PCR analysis revealed that the expression of hTERT and c-myc mRNA was down-regulated by genistein, whereas p21 mRNA increased in response to genistein. Luciferase reporter assay revealed that genistein reduced the transcriptional activity of hTERT. In DU-145 cells, telomerase activity and the expression of hTERT mRNA were also reduced by genistein.


CONCLUSIONS
The current study elucidated the molecular mechanism of cell growth inhibition by genistein. The antiproliferative effects of genistein seem to be exerted on the hTERT transcriptional activity via different molecular pathways.
Ouchi
Hideki
H
Department of Urology, Yokohama City University Graduate School of Medicine, Yokohama, Japan.
Ishiguro
Hitoshi
H
Ikeda
Naoya
N
Hori
Mayumi
M
Kubota
Yoshinobu
Y
Uemura
Hiroji
H
D000970:Antineoplastic Agents / Q000494:pharmacology*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D050759:Cyclin-Dependent Kinase Inhibitor p21; D015536:Down-Regulation; D019833:Genistein / Q000494:pharmacology*; D006801:Humans; D008297:Male; D016133:Polymerase Chain Reaction; D017430:Prostate-Specific Antigen / Q000097:blood / Q000187:drug effects; D011471:Prostatic Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D019098:Telomerase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D014158:Transcription, Genetic; D014162:Transfection; D014407:Tumor Cells, Cultured
D000970:Antineoplastic Agents; C493956:CDKN1A protein, human; D018797:Cell Cycle Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; C489427:MYC protein, human; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D019833:Genistein; D019098:Telomerase; D017430:Prostate-Specific Antigen