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06:48

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Published on: September 19, 2013

PTEN inhibits cell proliferation and induces apoptosis by downregulating cell surface IGF-IR expression in prostate

Hong Zhao1, Joelle Dupont, Shoshana Yakar

  • 1Diabetes Branch, NIDDK, National Institute of Health, Room 8D12, Bldg 10, Bethesda, MD 20892-1758, USA.

Oncogene
|January 23, 2004
PubMed

Insights

The tumor suppressor PTEN (phosphatase and tensin homolog) regulates cell proliferation and apoptosis. Overexpressing PTEN in prostate cancer cells inhibited growth and increased apoptosis by reducing insulin-like growth factor-I receptor synthesis.

Area of Science:

  • Molecular Biology
  • Cancer Research
  • Cell Biology

Background:

  • PTEN (phosphatase and tensin homolog) is a critical tumor suppressor gene frequently altered in human cancers.
  • PTEN functions as a lipid phosphatase, regulating the phosphatidylinositol-3'-kinase/AKT pathway, which controls cell proliferation and apoptosis.
  • Prostate cancer cells (PC3) lacking PTEN were used to investigate its tumor-suppressive functions.

Purpose of the Study:

  • To elucidate the role of PTEN in regulating cell proliferation and apoptosis in prostate cancer.
  • To investigate the molecular mechanisms by which PTEN influences these cellular processes.

Main Methods:

  • Stable overexpression of PTEN in PTEN-null PC3 prostate cancer cells.
  • Assessment of cell proliferation and apoptosis (serum starvation-induced).
  • Quantification of total and cell surface insulin-like growth factor-I receptor (IGF-IR) protein levels.
  • [35S]methionine pulse-chase experiments to analyze IGF-IR synthesis and degradation.

Main Results:

  • PTEN overexpression significantly inhibited cell proliferation and increased apoptosis in PC3 cells.
  • PTEN overexpression led to a substantial reduction (44-60%) in total IGF-IR protein and (49-64%) in cell surface IGF-IR expression.
  • Pulse-chase experiments revealed that PTEN overexpression decreases IGF-IR precursor synthesis, not its degradation.

Conclusions:

  • PTEN regulates prostate cancer cell proliferation and apoptosis by inhibiting the synthesis of IGF-IR.
  • These findings highlight a novel mechanism involving PTEN and IGF-IR in prostate cancer development.
  • Targeting the PTEN-IGF-IR axis may offer therapeutic strategies for prostate cancer.

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