Autophagy induced by p53-reactivating molecules protects pancreatic cancer cells from apoptosis

Apoptosis. 2013 Mar;18(3):337-46. doi: 10.1007/s10495-012-0790-6.

Abstract

TP53 mutations compromising p53 transcriptional function occur in more than 50 % of human cancers, including pancreatic adenocarcinoma, and render cancer cells more resistant to conventional therapy. In the last few years, many efforts have been addressed to identify p53-reactivating molecules able to restore the wild-type transcriptionally competent conformation of the mutated proteins. Here, we show that two of these compounds, CP-31398 and RITA, induce cell growth inhibition, apoptosis, and autophagy by activating p53/DNA binding and p53 phosphorylation (Ser15), without affecting the total p53 amount. These effects occur in both wild-type and mutant p53 pancreatic adenocarcinoma cell lines, whereas they are much less pronounced in normal human primary fibroblasts. Furthermore, CP-31398 and RITA regulate the axis SESN1-2/AMPK/mTOR by inducing AMPK phosphorylation on Thr172, which has a crucial role in the autophagic response. The protective role of autophagy in cell growth inhibition by CP-31398 and RITA is supported by the finding that the AMPK inhibitor compound C or the autophagy inhibitors chloroquine or 3-methyladenine sensitize both pancreatic adenocarcinoma cell lines to the apoptotic response induced by p53-reactivating molecules. Our results demonstrate for the first time a survival role for autophagy induced by p53-reactivating molecules, supporting the development of an anti-cancer therapy based on autophagy inhibition associated to p53 activation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • AMP-Activated Protein Kinases / antagonists & inhibitors
  • AMP-Activated Protein Kinases / metabolism
  • Adenine / analogs & derivatives
  • Adenine / pharmacology
  • Apoptosis / drug effects*
  • Autophagy / drug effects*
  • Cell Line, Tumor
  • Enzyme Activation
  • Furans / pharmacology
  • Humans
  • Pancreatic Neoplasms / drug therapy*
  • Pyrimidines / pharmacology*
  • TOR Serine-Threonine Kinases / metabolism
  • Tumor Suppressor Protein p53 / genetics
  • Tumor Suppressor Protein p53 / metabolism*

Substances

  • Furans
  • NSC 652287
  • Pyrimidines
  • Tumor Suppressor Protein p53
  • 3-methyladenine
  • MTOR protein, human
  • TOR Serine-Threonine Kinases
  • AMP-Activated Protein Kinases
  • CP 31398
  • Adenine