E3 ubiquitin protein ligase, E6-associated protein (E6-AP) regulates PI3K-Akt signaling and prostate cell growth

Sathish Srinivasan, Zafar Nawaz

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

This study elucidates the role of E6-associated protein, E6-AP (a dual function steroid hormone receptor coactivator and ubiquitin-protein ligase) in the regulation of PI3K-Akt signaling pathway, prostate gland growth and proliferation. Here, we report the generation of transgenic mice and prostate cancer cell line, LNCaP cells that overexpress E6-AP protein. Using these models we show that the levels of total Akt and phosphorylated Akt (active Akt) are increased in E6-AP overexpressing prostate gland and LNCaP cells suggesting that E6-AP regulates the PI3K-Akt signaling pathway. The prostate glands in our transgenic mice are ~. 20% larger and produce preneoplastic lesions at the age of 18. months. Our data also suggest that E6-AP modulates PI3K-Akt signaling pathway by both androgen-independent and -dependent mechanisms. In the androgen-independent mechanism, E6-AP modulates PI3K-Akt signaling by regulating the protein levels of RhoA, a small GTPase, which is a negative regulator of the Akt signaling pathway. Further, we show that E6-AP, a known coactivator of AR, amplifies the androgen-dependent activation of PI3K-Akt signaling pathway. In addition, we show that stable overexpression of E6-AP in prostate cancer cells results in increased cell size and proliferation. Overall our data suggests that E6-AP regulates both the positive and negative modulators of the PI3K-Akt pathway in prostate cells which results in increased prostate cell growth, proliferation and decreased apoptosis.

Original languageEnglish (US)
Pages (from-to)119-127
Number of pages9
JournalBiochimica et Biophysica Acta - Gene Regulatory Mechanisms
Volume1809
Issue number2
DOIs
StatePublished - Feb 2011

Keywords

  • Androgen receptor
  • E6-AP
  • PI3K-AKT
  • Prostate gland
  • RhoA

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Genetics
  • Molecular Biology
  • Structural Biology

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