Role of PI3K/AKT/mTOR signaling in the cell cycle progression of human prostate cancer

Biochem Biophys Res Commun. 2003 Oct 31;310(4):1124-32. doi: 10.1016/j.bbrc.2003.09.132.


Prostate cancer is one of the most common cancers among men. Recent studies demonstrated that PI3K signaling is an important intracellular mediator which is involved in multiple cellular functions including proliferation, differentiation, anti-apoptosis, tumorigenesis, and angiogenesis. In the present study, we demonstrate that the inhibition of PI3K activity by LY294002, inhibited prostate cancer cell proliferation and induced the G(1) cell cycle arrest. This effect was accompanied by the decreased expression of G(1)-associated proteins including cyclin D1, CDK4, and Rb phosphorylation at Ser780, Ser795, and Ser807/811, whereas expression of CDK6 and beta-actin was not affected by LY294002. The expression of cyclin kinase inhibitor, p21(CIP1/WAF1), was induced by LY294002, while levels of p16(INK4) were decreased in the same experiment. The inhibition of PI3K activity also inhibited the phosphorylation and p70(S6K), but not MAPK. PI3K regulates cell cycle through AKT, mTOR to p70(S6K). The mTOR inhibitor rapamycin has similar inhibitory effects on G(1) cell cycle progression and expression of cyclin D1, CDK4, and Rb phosphorylation. These results suggest that PI3K mediates G(1) cell cycle progression and cyclin expression through the activation of AKT/mTOR/p70(S6K) signaling pathway in the prostate cancer cells.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Cell Cycle*
  • GTP-Binding Proteins / metabolism
  • Humans
  • Male
  • Phosphatidylinositol 3-Kinases / metabolism*
  • Phosphorylation
  • Prostatic Neoplasms / enzymology
  • Prostatic Neoplasms / metabolism*
  • Prostatic Neoplasms / pathology
  • Protein Kinases / metabolism*
  • Protein-Serine-Threonine Kinases*
  • Proto-Oncogene Proteins / metabolism*
  • Proto-Oncogene Proteins c-akt
  • Ribosomal Protein S6 Kinases / metabolism
  • Signal Transduction*
  • TOR Serine-Threonine Kinases
  • Tumor Cells, Cultured


  • Proto-Oncogene Proteins
  • Protein Kinases
  • Phosphatidylinositol 3-Kinases
  • MTOR protein, human
  • TOR Serine-Threonine Kinases
  • AKT1 protein, human
  • Protein-Serine-Threonine Kinases
  • Proto-Oncogene Proteins c-akt
  • Ribosomal Protein S6 Kinases
  • GTP-Binding Proteins