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. 2014 Mar 15;74(6):1870-1880.
doi: 10.1158/0008-5472.CAN-13-2485. Epub 2014 Jan 30.

p300 acetyltransferase regulates androgen receptor degradation and PTEN-deficient prostate tumorigenesis

Jian Zhong #  1   2   3 , Liya Ding #  1   2   3 , Laura R Bohrer  4 , Yunqian Pan  1 , Ping Liu  4 , Jun Zhang  5 , Thomas J Sebo  5 , R Jeffrey Karnes  2 , Donald J Tindall  2   3 , Jan van Deursen  1   3 , Haojie Huang  1   2   3
Affiliations

p300 acetyltransferase regulates androgen receptor degradation and PTEN-deficient prostate tumorigenesis

Jian Zhong et al. Cancer Res. .

Abstract

Overexpression of the histone acetyltransferase p300 is implicated in the proliferation and progression of prostate cancer, but evidence of a causal role is lacking. In this study, we provide genetic evidence that this generic transcriptional coactivator functions as a positive modifier of prostate tumorigenesis. In a mouse model of PTEN deletion-induced prostate cancer, genetic ablation of p300 attenuated expression of the androgen receptor (AR). This finding was confirmed in human prostate cancer cells in which PTEN expression was abolished by RNA interference-mediated attenuation. These results were consistent with clinical evidence that the expression of p300 and AR correlates positively in human prostate cancer specimens. Mechanistically, PTEN inactivation increased AR phosphorylation at serine 81 (Ser81) to promote p300 binding and acetylation of AR, thereby precluding its polyubiquitination and degradation. In support of these findings, in PTEN-deficient prostate cancer in the mouse, we found that p300 was crucial for AR target gene expression. Taken together, our work identifies p300 as a molecular determinant of AR degradation and highlights p300 as a candidate target to manage prostate cancer, especially in cases marked by PTEN loss.

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Figures

Figure 1
Figure 1
P300 deletion inhibits PTEN-deficient prostate tumorigenesis in mice. A, IHC for Pten (i), phosphorylated Akt (Akt-S473-p) (ii) and p300 (iii) in prostate sections of 4-month-old ‘wild-type’, Ptenpc−/−, p300pc−/−, p300pc−/−;Ptenpc−/− mice (n = 8/group). The inset shows a high magnification image of the representative (framed) area in each panel. Scar bar, 50 μm. Scare bar in inset, 10 μm. B, H&E analysis of ventral prostate (VP) of 4-month-old mice with indicated genotypes (n = 8/genotype). Scar bar, 50 μm. C, IHC for smooth muscle actin (SMA) in the prostate of Ptenpc−/− and p300pc−/−;Ptenpc−/− mice. Arrows: disrupted and absent smooth muscle stroma in the Ptenpc−/− mouse. Scar bar, 50 μm. D, quantification of nonmalignant, low-grade PIN (LGPIN) and high-grade PIN (HGPIN) or cancerous (with areas suggestive of microinvasion) acini in the prostates (including AP, VP and DLP) of mice with the indicated genotypes (n = 8/genotype). E, representatives of genitourinary tracts of Ptenpc−/− and p300pc−/−;Ptenpc−/− mice (n = 6/genotype) that survived to 8 months. B, bladder; AP, anterior prostate; VP, ventral prostate. Scar bar, 2 mm. F, Ptenpc−/− mice lacking p300 in the prostates tend to live longer. Survival was monitored for 12 months and is displayed using Kaplan-Meyer plots.
Figure 2
Figure 2
P300 knockout decreases cell proliferation and AR protein levels in PTEN-deleted prostate tumors in mice. A, IHC for Ki-67 in the prostates of 4-month-old mice with indicated genotypes (n = 3/group). The inset in each panel shows a representative (framed) area in high magnification. Scar bar, 50 μm. Scare bar in inset, 10 μm. B, quantitative data of Ki-67 staining shown in (A). Columns, mean values of Ki-67 positive cells among three individual mice. Error bars, SD. *, p < 0.01. C, IHC of AR protein in the prostates of 4-month-old mice with indicated genotypes (n = 3/group). Scar bar, 50 μm. D, western blot analysis of indicated proteins in cell lysates prepared from the prostates of three mice in each group at 4 months of age.
Figure 3
Figure 3
IHC of p300 and AR proteins in human PCa specimens. A-C, representative images of H&E staining (A), p300 (B) and AR IHC (C) in prostate cancers exhibiting high and low expression of p300 and AR proteins. Scale bar, 100 μm. Insets show high magnification images of framed areas, scale bar, 50 μm. D, scoring data of the staining index for expression of p300 and AR proteins in human PCa specimens examined.
Figure 4
Figure 4
P300 regulates AR ubiquitination and proteasome degradation in PCa cells. A, p300 knockdown induces AR proteasome degradation. LAPC4 cells were transfected as indicated. 64 h later, cells were treated with vehicle or MG132 (20 uM) for 8 h followed by western blot (WB) analysis. B, LAPC4 cells were transfected with indicated siRNAs for 72 h and then treated with MG132 for 8 h followed by IP and WB analyses. C, AR-negative PC-3 cells were transfected with wild-type AR (AR-WT) and mutants (K630,632,633A and K630,632,633Q) in combination with HA-tagged Ub for 16 h, followed by treatment with MG132 (20 uM) for 8 h. Cell lysates were subjected to IP and WB as in (B). D, PC-3 cells were transfected with the plasmids as indicated for 16 h, followed by treatment with MG132 (20 uM) for 8 h. Cell lysates were subjected to IP and WB as in (B). E, effect of AKT on p300 and PTEN regulation of AR degradation. LAPC-4 cells were transfected with indicated siRNAs for 72 h, followed by treatment of LY294002 for 12 h and WB analysis. F, effect of AKT phosphorylation of AR at Ser213 and Ser791 on p300 and PTEN regulation of AR degradation. DU145 PCa cells were transfected with plasmids and siRNAs as indicated for 48 h followed by WB analysis.
Figure 5
Figure 5
AR Ser81 phosphorylation by CDK1 is crucial for p300-AR interaction, AR acetylation and p300 regulation of AR ubiquitination. A, LAPC4 cells were transfected with indicated siRNAs for 72 h followed by WB analysis. B, 293T cells were transfected with wild-type and S81A mutated AR for 24 h followed by treatment with 10 nM mibolerone (Mib) for additional 24 h. Cell lysates were subjected to IP and WB. C, 293T cells were transfected with AR-WT and S81A mutant in combination with or without CDK1 and cyclin B1 for 24 h followed by treatment with 10 nM Mib for additional 24 h. Cell lysates were subjected to IP and WB. D, 293T cells were transfected with the indicated plasmids for 24 h followed by treatment with 10 nM Mib in combination with or without 10 μM roscovitine for 24 h. Cell lysates were subjected to IP and WB. E, 293T cells were transfected with the indicated plasmids for 24 h and treated with 10 nM Mib for 24 h. Cell lysates were subjected to IP and WB analysis. F, 293T cells were transfected with the plasmids and siRNAs as indicated for 24 h and treated 10 nM Mib for 24 h. Cell lysates were subjected to IP and WB. G, LAPC4 cells were transfected with indicated siRNAs for 72 h followed by WB analysis.
Figure 6
Figure 6
P300 depletion impairs AR target gene expression in PTEN-deficiency PCa cells. A-C, RT-qPCR (upper panels) and IHC (lower panels) analyses of expression of AR target genes Pb (A), Nkx3.1 (B) and Mme (C) in prostate tissues from mice (n = 3) with the indicated genotypes at 4 months of age. Columns, mean values among three replicates; error bars, SD. *, p < 0.01. Lower panels: representative IHC staining of Pb (cytoplasmic and secreted out of cells), Nkx3.1 (cytoplasmic) and Mme (plasma membrane). D, LAPC4 cells were transfected as indicated for 48 h and treated with 10 nM Mib for 24 h. Expression of indicated genes was analyzed by RT-qPCR. Columns, mean values among three replicates; error bars, SD. *, p < 0.01. E, A diagram depicts the role of p300 and CDK phosphorylation of AR at Ser81 in regulation of AR stabilization and function by inhibiting PTEN loss or AKT activation-induced AR ubiquitination. Ac with circle, acetylation. P with circle, phosphorylation. Ub, ubiquitin.
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References

    1. Debes JD, Tindall DJ. Mechanisms of androgen-refractory prostate cancer. N Engl J Med. 2004;351:1488–90. - PubMed
    1. Isaacs JT. Antagonistic effect of androgen on prostatic cell death. Prostate. 1984;5:545–57. - PubMed
    1. Scher HI, Sawyers CL. Biology of progressive, castration-resistant prostate cancer: directed therapies targeting the androgen-receptor signaling axis. J Clin Oncol. 2005;23:8253–61. - PubMed
    1. Scher HI, Fizazi K, Saad F, Taplin ME, Sternberg CN, Miller K, et al. Increased survival with enzalutamide in prostate cancer after chemotherapy. N Engl J Med. 2012;367:1187–97. - PubMed
    1. de Bono JS, Logothetis CJ, Molina A, Fizazi K, North S, Chu L, et al. Abiraterone and increased survival in metastatic prostate cancer. N Engl J Med. 2011;364:1995–2005. - PMC - PubMed

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