Interruption of nuclear factor kappaB signaling by the androgen receptor facilitates 12-O-tetradecanoylphorbolacetate-induced apoptosis in androgen-sensitive prostate cancer LNCaP cells.
12-O-tetradecanoylphorbolacetate (TPA) influences proliferation, differentiation, and apoptosis in a variety of cells including prostate cancer cells. Here, we show that androgen treatment potentiates TPA-induced apoptosis in androgen-sensitive prostate cancer LNCaP cells but not in androgen-independent prostate cancer cell lines DU145 and PC-3. The use of the antiandrogen bicalutamide (Casodex) rescued LNCaP cells from 5-alpha-dihydrotestosterone (DHT)/TPA-induced apoptosis, suggesting that DHT/TPA-induced apoptosis is mediated by androgen/androgen receptor (AR). In addition, a caspase-3 inhibitor (Ac-DEVD-CHO) reduced the level of apoptosis, suggesting that DHT/TPA-mediated apoptosis occurs through a caspase-3-dependent pathway. A functional reporter assay using nuclear factor (NF) kappaB-luciferase and an electromobility gel shift assay showed that DHT suppressed NFkappaB activity. In addition, apoptosis mediated by combined DHT/TPA treatment was abrogated by overexpression of the NFkappaB subunit p65 in LNCaP-p65 cells, suggesting that NFkappaB may play an important role in regulating the effects of androgen/AR and TPA on apoptosis. Furthermore, use of the c-Jun N-terminal kinase (JNK) inhibitor SB202190 showed that the combination of DHT/TPA increased JNK activation in LNCaP cells but not in LNCaP-p65 cells, demonstrating that NFkappaB may be able to suppress JNK activity. These results indicate that androgen/AR facilitates TPA-induced apoptosis by interruption of the NFkappaB signaling pathway, leading to activation of JNK in LNCaP cells. These data describe a signaling pathway that could potentially be useful in proposed therapeutic treatment strategies exploiting combinations of different agents that control apoptosis in prostate tumors.
Altuwaijri
Saleh
S
George Whipple Laboratory for Cancer Research, Department of Pathology, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642, USA.
Lin
Hui-Kuan
HK
Chuang
Kuang-Hsiang
KH
Lin
Wen-Jye
WJ
Yeh
Shuyuan
S
Hanchett
LeRoy A
LA
Rahman
Mujib M
MM
Kang
Hong-Yo
HY
Tsai
Meng-Ying
MY
Zhang
Yanqing
Y
Yang
Lin
L
Chang
Chawnshang
C
D000728:Androgens / Q000502:physiology; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D045744:Cell Line, Tumor; D013196:Dihydrotestosterone / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases; D008297:Male; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology; D009376:Neoplasms, Hormone-Dependent / Q000188:drug therapy / Q000235:genetics / Q000473:pathology*; D011471:Prostatic Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000473:pathology*; D011944:Receptors, Androgen / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D051996:Transcription Factor RelA; D014162:Transfection
D000728:Androgens; D016328:NF-kappa B; D011944:Receptors, Androgen; D051996:Transcription Factor RelA; D013196:Dihydrotestosterone; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; D013755:Tetradecanoylphorbol Acetate