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Poly (A) Binding Protein Cytoplasmic 1 Is a Novel Co-Regulator of the Androgen Receptor.

Eisermann K, Dar JA, Dong J, Wang D, Masoodi KZ, Wang Z - PLoS ONE (2015)

Bottom Line: Mass spectrometry analysis of the pulled down proteins identified poly (A) binding protein cytoplasmic 1 (PABPC1) interaction with this region of the AR.Knockdown of PABPC1 decreased nuclear AR protein levels and inhibited androgen activation of the AR target PSA in LNCaP and C4-2 cells.These findings suggest that PABPC1 is a novel co-regulator of the AR and may be a potential target for blocking activation of the AR in CRPC.

View Article: PubMed Central - PubMed

Affiliation: Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America.

ABSTRACT
The androgen receptor (AR) is a member of the steroid receptor superfamily that regulates gene expression in a ligand-dependent manner. The NTD of the AR plays a key role in AR transactivation including androgen-independent activation of the AR in castration-resistant prostate cancer (CRPC) cells. We recently reported that amino acids (a.a.) 50-250 of the NTD are capable of modulating AR nucleocytoplasmic trafficking. To further explore the mechanism associated with a.a. 50-250, GFP pull-down assays were performed in C4-2 CRPC cells transfected with GFP tagged a.a. 50-250 of the AR. Mass spectrometry analysis of the pulled down proteins identified poly (A) binding protein cytoplasmic 1 (PABPC1) interaction with this region of the AR. In silico analysis of gene expression data revealed PABPC1 up-regulation in prostate cancer tissue specimens and this up-regulation correlates to increased disease recurrence. Co-immunoprecipitation assays confirmed the association of PABPC1 with a.a. 50-250 of the NTD of the AR. Knockdown of PABPC1 decreased nuclear AR protein levels and inhibited androgen activation of the AR target PSA in LNCaP and C4-2 cells. Additionally, knockdown of PABPC1 inhibited transactivation of the PSA promoter by NAR (AR lacking the LBD) and attenuated proliferation of AR-positive prostate cancer cells. These findings suggest that PABPC1 is a novel co-regulator of the AR and may be a potential target for blocking activation of the AR in CRPC.

No MeSH data available.


Related in: MedlinePlus

PABPC1 is expressed in prostate cancer cells.(A) Prostate cancer cell lines (PC3, LNCaP, C4-2, and 22Rv1) and normal prostate cells (WPMY-1) were analyzed by Western blot for protein expression levels of PABPC1 (Santa Cruz). (B) Expression levels of the AR in C4-2, LNCaP, and 22Rv1 cell lines. GAPDH (Santa Cruz) was used as a loading control. The numbers indicate the relative expression of PABPC1 or AR quantitated using ImageJ software when normalized to GAPDH.
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pone.0128495.g002: PABPC1 is expressed in prostate cancer cells.(A) Prostate cancer cell lines (PC3, LNCaP, C4-2, and 22Rv1) and normal prostate cells (WPMY-1) were analyzed by Western blot for protein expression levels of PABPC1 (Santa Cruz). (B) Expression levels of the AR in C4-2, LNCaP, and 22Rv1 cell lines. GAPDH (Santa Cruz) was used as a loading control. The numbers indicate the relative expression of PABPC1 or AR quantitated using ImageJ software when normalized to GAPDH.

Mentions: Prostate cancer cells (PC3, C4-2, LNCaP, and 22Rv1) and normal prostate stromal fibroblasts (WPMY-1) were examined to determine the relative expression levels of PABPC1 (Fig 2A). Western blot analysis showed that PABPC1 is expressed in all the tested cells with slightly higher expression in AR-positive prostate cancer cells (Fig 2B).


Poly (A) Binding Protein Cytoplasmic 1 Is a Novel Co-Regulator of the Androgen Receptor.

Eisermann K, Dar JA, Dong J, Wang D, Masoodi KZ, Wang Z - PLoS ONE (2015)

PABPC1 is expressed in prostate cancer cells.(A) Prostate cancer cell lines (PC3, LNCaP, C4-2, and 22Rv1) and normal prostate cells (WPMY-1) were analyzed by Western blot for protein expression levels of PABPC1 (Santa Cruz). (B) Expression levels of the AR in C4-2, LNCaP, and 22Rv1 cell lines. GAPDH (Santa Cruz) was used as a loading control. The numbers indicate the relative expression of PABPC1 or AR quantitated using ImageJ software when normalized to GAPDH.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4503479&req=5

pone.0128495.g002: PABPC1 is expressed in prostate cancer cells.(A) Prostate cancer cell lines (PC3, LNCaP, C4-2, and 22Rv1) and normal prostate cells (WPMY-1) were analyzed by Western blot for protein expression levels of PABPC1 (Santa Cruz). (B) Expression levels of the AR in C4-2, LNCaP, and 22Rv1 cell lines. GAPDH (Santa Cruz) was used as a loading control. The numbers indicate the relative expression of PABPC1 or AR quantitated using ImageJ software when normalized to GAPDH.
Mentions: Prostate cancer cells (PC3, C4-2, LNCaP, and 22Rv1) and normal prostate stromal fibroblasts (WPMY-1) were examined to determine the relative expression levels of PABPC1 (Fig 2A). Western blot analysis showed that PABPC1 is expressed in all the tested cells with slightly higher expression in AR-positive prostate cancer cells (Fig 2B).

Bottom Line: Mass spectrometry analysis of the pulled down proteins identified poly (A) binding protein cytoplasmic 1 (PABPC1) interaction with this region of the AR.Knockdown of PABPC1 decreased nuclear AR protein levels and inhibited androgen activation of the AR target PSA in LNCaP and C4-2 cells.These findings suggest that PABPC1 is a novel co-regulator of the AR and may be a potential target for blocking activation of the AR in CRPC.

View Article: PubMed Central - PubMed

Affiliation: Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America.

ABSTRACT
The androgen receptor (AR) is a member of the steroid receptor superfamily that regulates gene expression in a ligand-dependent manner. The NTD of the AR plays a key role in AR transactivation including androgen-independent activation of the AR in castration-resistant prostate cancer (CRPC) cells. We recently reported that amino acids (a.a.) 50-250 of the NTD are capable of modulating AR nucleocytoplasmic trafficking. To further explore the mechanism associated with a.a. 50-250, GFP pull-down assays were performed in C4-2 CRPC cells transfected with GFP tagged a.a. 50-250 of the AR. Mass spectrometry analysis of the pulled down proteins identified poly (A) binding protein cytoplasmic 1 (PABPC1) interaction with this region of the AR. In silico analysis of gene expression data revealed PABPC1 up-regulation in prostate cancer tissue specimens and this up-regulation correlates to increased disease recurrence. Co-immunoprecipitation assays confirmed the association of PABPC1 with a.a. 50-250 of the NTD of the AR. Knockdown of PABPC1 decreased nuclear AR protein levels and inhibited androgen activation of the AR target PSA in LNCaP and C4-2 cells. Additionally, knockdown of PABPC1 inhibited transactivation of the PSA promoter by NAR (AR lacking the LBD) and attenuated proliferation of AR-positive prostate cancer cells. These findings suggest that PABPC1 is a novel co-regulator of the AR and may be a potential target for blocking activation of the AR in CRPC.

No MeSH data available.


Related in: MedlinePlus