The phosphatidylinositol 3-kinase/AKT signal transduction pathway plays a critical role in the expression of p21WAF1/CIP1/SDI1 induced by cisplatin and paclitaxel

Cancer Res. 2000 Oct 1;60(19):5390-4.

Abstract

The cyclin-dependent kinase inhibitor p21WAF1/CIP1/SD11 (p21) plays a crucial role in DNA repair, cell differentiation, and apoptosis through regulation of the cell cycle. A2780 human ovarian carcinoma cells, which are sensitive to cisplatin and paclitaxel, express wild-type p53 and exhibit a p53-mediated increase in p21 in response to the chemotherapeutic agents. Here, we demonstrate that phosphatidylinositol 3-kinase (PI3K) and its downstream targets serine/threonine kinases AKT1 and AKT2 (AKT), are required for the full induction of p21 in A2780 cells treated with cisplatin or paclitaxel. Inactivation of the PI3K/AKT signal transduction pathway either by its specific inhibitor LY294002 or by expression of dominant negative AKT inhibited p21 expression but had no inhibitory effect on the expression of the proapoptotic protein BAX by cisplatin and paclitaxel treatment. In addition, overexpression of wild-type or constitutively active AKT in A2780 cells sustained the regulation of p21 induction or increased the level of p21 expression, respectively. Experiments with additional ovarian carcinoma cell lines revealed that PI3K is involved in the expression of p21 induced by cisplatin or paclitaxel in OVCAR-10 cells, which have wild-type p53, but not in OVCAR-5 cells, which lack functional p53. These data indicate that the PI3K/AKT signal transduction pathway mediates p21 expression and suggest that this pathway contributes to cell cycle regulation promoted by p53 in response to drug-induced stress. However, inactivation of PI3K/AKT signaling did not result in significant alteration of the drug sensitivity of A2780 cells, suggesting that the cell death induced by cisplatin or paclitaxel proceeds independently of cell protective effects of PI3K and AKT.

Publication types

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

MeSH terms

  • Antineoplastic Agents / pharmacology
  • Antineoplastic Agents, Phytogenic / pharmacology
  • Cell Death / drug effects
  • Cell Death / physiology
  • Cisplatin / pharmacology*
  • Cyclin-Dependent Kinase Inhibitor p21
  • Cyclins / biosynthesis*
  • Cyclins / genetics
  • Enzyme Activation / drug effects
  • Female
  • Humans
  • Ovarian Neoplasms / drug therapy
  • Ovarian Neoplasms / enzymology
  • Ovarian Neoplasms / metabolism
  • Paclitaxel / pharmacology*
  • Phosphatidylinositol 3-Kinases / physiology*
  • Protein Serine-Threonine Kinases / physiology*
  • Proto-Oncogene Proteins / physiology*
  • Proto-Oncogene Proteins c-akt
  • RNA, Messenger / biosynthesis
  • RNA, Messenger / genetics
  • Signal Transduction / drug effects
  • Signal Transduction / physiology*
  • Tumor Cells, Cultured

Substances

  • Antineoplastic Agents
  • Antineoplastic Agents, Phytogenic
  • CDKN1A protein, human
  • Cyclin-Dependent Kinase Inhibitor p21
  • Cyclins
  • Proto-Oncogene Proteins
  • RNA, Messenger
  • AKT1 protein, human
  • AKT2 protein, human
  • Protein Serine-Threonine Kinases
  • Proto-Oncogene Proteins c-akt
  • Paclitaxel
  • Cisplatin