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Deubiquitinating enzyme Usp12 regulates the interaction between the androgen receptor and the Akt pathway.

McClurg UL, Summerscales EE, Harle VJ, Gaughan L, Robson CN - Oncotarget (2014)

Bottom Line: We have recently reported that AR is deubiquitinated and stabilised by Usp12 resulting in increased transcriptional activity.In this report we demonstrate that Usp12, in complex with Uaf-1 and WDR20, directly deubiquitinates and stabilises the Akt phosphatases PHLPP and PHLPPL resulting in decreased levels of active pAkt.Decreased pAkt in turn down-regulates AR Ser213 phosphorylation resulting in enhanced receptor stability and transcriptional activity.

View Article: PubMed Central - PubMed

Affiliation: Solid Tumour Target Discovery Laboratory, Newcastle Cancer Centre, Northern Institute for Cancer Research, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.

ABSTRACT
The androgen receptor (AR) is a transcription factor involved in prostate cell growth, homeostasis and transformation regulated by post-translational modifications, including ubiquitination. We have recently reported that AR is deubiquitinated and stabilised by Usp12 resulting in increased transcriptional activity. In this study we have investigated the relationship between Usp12, PHLPP and PHLPPL tumour suppressors in the regulation of AR transcriptional activity in prostate cancer (PC). PHLPP and PHLPPL are pro-apoptotic phosphatases that dephosphorylate and subsequently deactivate Akt. Phosphorylated Akt is reported to deactivate AR in PC by phosphorylation at Ser213 and Ser791 leading to ligand dissociation and AR degradation. In contrast, PHLPP- and PHLPPL-mediated dephosphorylation and inactivation of Akt elevates the levels of active AR. In this report we demonstrate that Usp12, in complex with Uaf-1 and WDR20, directly deubiquitinates and stabilises the Akt phosphatases PHLPP and PHLPPL resulting in decreased levels of active pAkt. Decreased pAkt in turn down-regulates AR Ser213 phosphorylation resulting in enhanced receptor stability and transcriptional activity. Additionally, we observe that depleting Usp12 sensitises PC cells to therapies aimed at Akt inhibition irrespectively of their sensitivity to androgen ablation therapy. We propose that Usp12 inhibition could offer a therapeutic alternative for castration resistant prostate cancer.

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Related in: MedlinePlus

Usp12 depletion sensitises PC cells to Akt inhibition irrespectively of their castration sensitivity and AR status indicated by decreased cellular occupation of the wells(A-C) LNCaP, LNCaP-AI and PC3 cells respectively were treated with siRNA and compounds as indicated. Cells were grown in their respective full media (FM); LNCaP and PC3 cells were grown in steroid containing media and LNCaP-AI were grown in steroid depleted media. Cellular occupation of the wells was measured every 4h using the IncuCyte system. Data are a mean of three independent experiments.
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Figure 5: Usp12 depletion sensitises PC cells to Akt inhibition irrespectively of their castration sensitivity and AR status indicated by decreased cellular occupation of the wells(A-C) LNCaP, LNCaP-AI and PC3 cells respectively were treated with siRNA and compounds as indicated. Cells were grown in their respective full media (FM); LNCaP and PC3 cells were grown in steroid containing media and LNCaP-AI were grown in steroid depleted media. Cellular occupation of the wells was measured every 4h using the IncuCyte system. Data are a mean of three independent experiments.

Mentions: Our data confirms that Usp12 controls the levels of pAkt in PC cells by deubiquitinating and stabilising two Akt phosphatases PHLPP and PHLPPL. Depleting Usp12 results in increased pAkt and as such predisposes Akt to be a major driver of cellular proliferation under those conditions. To assess the impact of Usp12 depletion on Akt inhibition we used three different compounds, GDC-0941 which is a PI3K inhibitor acting upstream of Akt and two direct Akt inhibitors MK-2206 and Perifosine. We analysed cellular proliferation in LNCaP (castration sensitive), LNCaP-AI (castration resistant) and PC3 (AR negative) PC cells using two separate assays. We report that depleting Usp12 significantly sensitised PC cells to Akt inhibition irrespectively of their castration sensitivity or AR status (Figure 5A-C and 6A-C).


Deubiquitinating enzyme Usp12 regulates the interaction between the androgen receptor and the Akt pathway.

McClurg UL, Summerscales EE, Harle VJ, Gaughan L, Robson CN - Oncotarget (2014)

Usp12 depletion sensitises PC cells to Akt inhibition irrespectively of their castration sensitivity and AR status indicated by decreased cellular occupation of the wells(A-C) LNCaP, LNCaP-AI and PC3 cells respectively were treated with siRNA and compounds as indicated. Cells were grown in their respective full media (FM); LNCaP and PC3 cells were grown in steroid containing media and LNCaP-AI were grown in steroid depleted media. Cellular occupation of the wells was measured every 4h using the IncuCyte system. Data are a mean of three independent experiments.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4196185&req=5

Figure 5: Usp12 depletion sensitises PC cells to Akt inhibition irrespectively of their castration sensitivity and AR status indicated by decreased cellular occupation of the wells(A-C) LNCaP, LNCaP-AI and PC3 cells respectively were treated with siRNA and compounds as indicated. Cells were grown in their respective full media (FM); LNCaP and PC3 cells were grown in steroid containing media and LNCaP-AI were grown in steroid depleted media. Cellular occupation of the wells was measured every 4h using the IncuCyte system. Data are a mean of three independent experiments.
Mentions: Our data confirms that Usp12 controls the levels of pAkt in PC cells by deubiquitinating and stabilising two Akt phosphatases PHLPP and PHLPPL. Depleting Usp12 results in increased pAkt and as such predisposes Akt to be a major driver of cellular proliferation under those conditions. To assess the impact of Usp12 depletion on Akt inhibition we used three different compounds, GDC-0941 which is a PI3K inhibitor acting upstream of Akt and two direct Akt inhibitors MK-2206 and Perifosine. We analysed cellular proliferation in LNCaP (castration sensitive), LNCaP-AI (castration resistant) and PC3 (AR negative) PC cells using two separate assays. We report that depleting Usp12 significantly sensitised PC cells to Akt inhibition irrespectively of their castration sensitivity or AR status (Figure 5A-C and 6A-C).

Bottom Line: We have recently reported that AR is deubiquitinated and stabilised by Usp12 resulting in increased transcriptional activity.In this report we demonstrate that Usp12, in complex with Uaf-1 and WDR20, directly deubiquitinates and stabilises the Akt phosphatases PHLPP and PHLPPL resulting in decreased levels of active pAkt.Decreased pAkt in turn down-regulates AR Ser213 phosphorylation resulting in enhanced receptor stability and transcriptional activity.

View Article: PubMed Central - PubMed

Affiliation: Solid Tumour Target Discovery Laboratory, Newcastle Cancer Centre, Northern Institute for Cancer Research, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.

ABSTRACT
The androgen receptor (AR) is a transcription factor involved in prostate cell growth, homeostasis and transformation regulated by post-translational modifications, including ubiquitination. We have recently reported that AR is deubiquitinated and stabilised by Usp12 resulting in increased transcriptional activity. In this study we have investigated the relationship between Usp12, PHLPP and PHLPPL tumour suppressors in the regulation of AR transcriptional activity in prostate cancer (PC). PHLPP and PHLPPL are pro-apoptotic phosphatases that dephosphorylate and subsequently deactivate Akt. Phosphorylated Akt is reported to deactivate AR in PC by phosphorylation at Ser213 and Ser791 leading to ligand dissociation and AR degradation. In contrast, PHLPP- and PHLPPL-mediated dephosphorylation and inactivation of Akt elevates the levels of active AR. In this report we demonstrate that Usp12, in complex with Uaf-1 and WDR20, directly deubiquitinates and stabilises the Akt phosphatases PHLPP and PHLPPL resulting in decreased levels of active pAkt. Decreased pAkt in turn down-regulates AR Ser213 phosphorylation resulting in enhanced receptor stability and transcriptional activity. Additionally, we observe that depleting Usp12 sensitises PC cells to therapies aimed at Akt inhibition irrespectively of their sensitivity to androgen ablation therapy. We propose that Usp12 inhibition could offer a therapeutic alternative for castration resistant prostate cancer.

Show MeSH
Related in: MedlinePlus