P62 regulates resveratrol-mediated Fas/Cav-1 complex formation and transition from autophagy to apoptosis

Oncotarget. 2015 Jan 20;6(2):789-801. doi: 10.18632/oncotarget.2733.

Abstract

Resveratrol is a potential polyphenol drug used in cancer treatment. We examined the relationship between autophagy and apoptosis in RSV-treated non-small lung adenocarcinoma A549 cells. Resveratrol treatment increased autophagy and autophagy-mediated degradation of P62. Immunocytochemistry revealed P62 co-localized with Fas/Cav-1 complexes, known to induce apoptosis. However, siRNA-mediated P62 downregulation enhanced formation of Fas/Cav-1 complexes, suggesting that P62 inhibited Fas/Cav-1 complex formation. Fas/Cav-1 complexes triggered caspase-8 activation and cleavage of Beclin-1, releasing a C-terminal Beclin-1 peptide that translocated to the mitochondria and initiate apoptosis. Inhibition of autophagy by siRNA-mediated repression of Beclin-1 also blocked RSV-induced apoptosis, showing a dependence of apoptosis on autophagy. P62 knockdown by siRNA accelerated the activation of caspase-8 and initiate apoptosis, while Cav-1 knockdown inhibited apoptosis, but increased autophagy. Inhibition of autophagy by 3-MA prevented both P62 degradation and induction of apoptosis, whereas inhibition of apoptosis by z-IETD-FMK or z-DEVD-FMK enhanced both P62 induction and autophagic cell death. In conclusion, P62 links resveratrol-induced autophagy to apoptosis. P62 blocks apoptosis by inhibiting Fas/Cav-1 complex formation, but RSV-induced autophagic degradation of P62 enables formation of Fas/Cav-1 complexes which then activate caspase-8-mediated Beclin-1 cleavage, resulting in translocation of the Beclin-1 C-terminal fragment to the mitochondria to initiate apoptosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents, Phytogenic / pharmacology
  • Apoptosis / drug effects
  • Autophagy / drug effects
  • Carcinoma, Non-Small-Cell Lung / drug therapy*
  • Carcinoma, Non-Small-Cell Lung / genetics
  • Carcinoma, Non-Small-Cell Lung / metabolism
  • Carcinoma, Non-Small-Cell Lung / pathology
  • Caveolin 1 / biosynthesis
  • Caveolin 1 / metabolism*
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Humans
  • Lung Neoplasms / drug therapy*
  • Lung Neoplasms / genetics
  • Lung Neoplasms / metabolism
  • Lung Neoplasms / pathology
  • RNA-Binding Proteins / genetics
  • RNA-Binding Proteins / metabolism*
  • Resveratrol
  • Stilbenes / pharmacology*
  • Transfection
  • fas Receptor / metabolism*

Substances

  • Antineoplastic Agents, Phytogenic
  • Caveolin 1
  • IGF2BP2 protein, human
  • P62 protein, human
  • RNA-Binding Proteins
  • Stilbenes
  • fas Receptor
  • Resveratrol