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Published on: October 24, 2019

PTEN induces chemosensitivity in PTEN-mutated prostate cancer cells by suppression of Bcl-2 expression

H Huang1, J C Cheville, Y Pan

  • 1Department of Urology Research, Mayo Foundation, Rochester, Minnesota 55905,USA.

The Journal of Biological Chemistry
|August 10, 2001
PubMed

Insights

Loss of the PTEN tumor suppressor gene in prostate cancer elevates Bcl-2, promoting cell survival and chemoresistance. Restoring PTEN function inhibits Bcl-2, offering therapeutic potential.

Area of Science:

  • Oncology
  • Molecular Biology
  • Genetics

Background:

  • The tumor suppressor gene PTEN is frequently lost in advanced prostate cancer (PCa).
  • The precise role of PTEN in PCa tumorigenesis and its downstream effects remain incompletely understood.
  • Bcl-2 expression is often dysregulated in cancer and promotes cell survival.

Purpose of the Study:

  • To investigate the functional relationship between PTEN loss and Bcl-2 expression in prostate cancer.
  • To elucidate the molecular mechanisms by which PTEN influences Bcl-2 regulation.
  • To assess the therapeutic implications of the PTEN-Bcl-2 axis in PCa chemoresistance.

Main Methods:

  • Analysis of PTEN protein and Bcl-2 expression in human prostate tumors and PCa cell lines.
  • PTEN gene transfection into PTEN-null PCa cells to assess effects on Bcl-2 mRNA and protein levels.
  • Luciferase reporter assays using the Bcl-2 promoter to study transcriptional regulation by PTEN.
  • Investigation of the roles of PTEN's lipid-phosphatase activity, Akt signaling, and CREB phosphorylation.

Main Results:

  • PTEN loss in PCa correlates with increased Bcl-2 expression.
  • Ectopic PTEN expression in PCa cells down-regulates Bcl-2 transcription, requiring PTEN's phosphatase activity and inhibited by Akt.
  • PTEN-induced Bcl-2 inhibition involves decreased CREB phosphorylation at Ser133.
  • Overexpression of Bcl-2 rescues PTEN-induced apoptosis but not cell cycle arrest and attenuates PTEN-mediated chemosensitivity.

Conclusions:

  • Loss of PTEN function in prostate cancer leads to Bcl-2 up-regulation, contributing to cancer cell survival and chemoresistance.
  • The PTEN-Bcl-2 pathway represents a critical mechanism driving PCa progression and treatment resistance.
  • Targeting the PTEN pathway holds promise for novel therapeutic strategies in prostate cancer treatment.

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