NF-kappaB2 processing and p52 nuclear accumulation after androgenic stimulation of LNCaP prostate cancer cells.
Several reports suggest that androgen signalling interferes with canonical RelA-p50 activity in androgen-sensitive cells. Whether this also occurs with non-canonical NF-kappaB subunits has not been studied. Here we report that androgenic stimulation of LNCaP cells with the androgen analogue R1881 appears to positively regulate the non-canonical NF-kappaB pathway as p52 accumulates both in the cytoplasm and nucleus after 48-72 h of stimulation. In contrast to TNF-alpha stimulation, androgen stimulation fails to induce RelB expression and is absent from nucleus of R1881-treated LNCaP cells. Electromobility shift assays reveal a time-dependent change in the nature of NF-kappaB complexes actively bound to DNA after 72 h of androgenic stimulation concomitant with the appearance of p52-containing complexes. Co-immunoprecipitation studies indicate that newly produced p52 can exist as a heterodimer with RelA or p50, but may be mainly present as a homodimer. RNAi experiments targeting IKK-alpha and IKK-beta show that the R1881-induced nuclear accumulation of p52 is IKK-alpha-dependent. These results point to a novel mechanism by which androgens regulate NF-kappaB and provide a rationale for further studies into the biological significance of non-canonical NF-kappaB signalling in prostate cancer.
Lessard
Laurent
L
Université de Montréal, Centre de recherche du CHUM et Institut du cancer de Montréal, 1560 Sherbrooke East, Montréal, QC, Canada, H2L 4M1.
Saad
Fred
F
Le Page
Cécile
C
Diallo
Jean-Simon
JS
Péant
Benjamin
B
Delvoye
Nathalie
N
Mes-Masson
Anne-Marie
AM
D000728:Androgens / Q000378:metabolism*; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D006801:Humans; D051550:I-kappa B Kinase / Q000378:metabolism; D008297:Male; D015741:Metribolone / Q000494:pharmacology; D052002:NF-kappa B p50 Subunit / Q000378:metabolism; D052003:NF-kappa B p52 Subunit / Q000378:metabolism*; D011471:Prostatic Neoplasms / Q000378:metabolism*; D011944:Receptors, Androgen / Q000378:metabolism; D015398:Signal Transduction; D045165:Testosterone Congeners / Q000494:pharmacology; D051996:Transcription Factor RelA / Q000378:metabolism
D000728:Androgens; D052002:NF-kappa B p50 Subunit; D052003:NF-kappa B p52 Subunit; D011944:Receptors, Androgen; D045165:Testosterone Congeners; D051996:Transcription Factor RelA; D015741:Metribolone; C496559:CHUK protein, human; D051550:I-kappa B Kinase