p300 mediates androgen-independent transactivation of the androgen receptor by interleukin 6.
Prostate cancer (PCa) begins as an androgen-dependent tumor that will eventually progress to an androgen-independent stage after androgen ablation. Although little is understood about this transition to androgen independence, the androgen receptor (AR) appears to be involved. The coactivator p300 has been shown to interact with the AR during its androgen-dependent transactivation. We show that p300 is involved downstream of the mitogen-activated protein kinase pathway during transactivation of the AR by interleukin-6 (IL-6). Furthermore, we demonstrate that sequestration of p300 with E1A inhibits the IL-6-dependent transactivation of the AR, and that increasing amounts of p300 reverse this inhibition. A mutant p300 that lacks histone acetyltransferase (HAT) activity did not reverse E1A-mediated inhibition. By using small-interference RNA designed to target p300 transcripts, we demonstrate that, after silencing p300, there was no induction of AR activity by IL-6. These findings reveal a unique role for p300 and its HAT activity, indicating that it is necessary for the ligand-independent transactivation of the AR in androgen-independent PCa cells.
Debes
Jose D
JD
Departments of Urology, Mayo Clinic and Foundation, Rochester, Minnesota 55905, USA.
Schmidt
Lucy J
LJ
Huang
Haojie
H
Tindall
Donald J
DJ
D000123:Acetyltransferases / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D000728:Androgens / Q000502:physiology; D018797:Cell Cycle Proteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D051548:Histone Acetyltransferases; D006801:Humans; D007150:Immunohistochemistry; D015850:Interleukin-6 / Q000494:pharmacology* / Q000502:physiology; D020935:MAP Kinase Signaling System / Q000502:physiology; D008297:Male; D009376:Neoplasms, Hormone-Dependent / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D011471:Prostatic Neoplasms / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics; D011944:Receptors, Androgen / Q000235:genetics / Q000502:physiology*; D014157:Transcription Factors; D015533:Transcriptional Activation / Q000502:physiology*; D014162:Transfection; D014407:Tumor Cells, Cultured; D050880:p300-CBP Transcription Factors; D000099224:p300-CBP-Associated Factor; D000093242:Interleukin-6 Inhibitors
D000123:Acetyltransferases; D000728:Androgens; D018797:Cell Cycle Proteins; D051548:Histone Acetyltransferases; D015850:Interleukin-6; D034741:RNA, Small Interfering; D011944:Receptors, Androgen; D014157:Transcription Factors; D050880:p300-CBP Transcription Factors; D000099224:p300-CBP-Associated Factor; D000093242:Interleukin-6 Inhibitors