Delayed caspase-8 activation and enhanced integrin β1-activated FAK underpins anoikis in oesophageal carcinoma cells harbouring mt p53-R175H

Cell Biol Int. 2011 Aug;35(8):819-26. doi: 10.1042/CBI20100894.

Abstract

FAK (focal adhesion kinase)-mediated signalling reportedly suppresses caspase-8 activation and, as a consequence, rescues epithelial cells from Fas-mediated anoikis. Critical was the use of a HOSCC (human oesophageal squamous carcinoma) cell line harbouring mt (mutant) p53-R175H and displaying resistance to detachment and Tyr397 dephosphorylation of FAK. Here we show, although caspase-8 activation is delayed in the mt p53-R175H cell line, comparable apoptotic events evidenced in the wt (wild type) p53 HOSCC cell lines could be induced in the mt p53-R175H cell line by strengthening the apoptotic stimulus. Significant to anoikis-related regulation, the delay in caspase-8 activation was accompanied by the maintenance of FAK Tyr397 phosphorylation, integrin β1-associated FAK and a FAK/caspase-8 complex. Thus, mt p53-R175H may desensitize tumours to Fas-mediated anchorage-independent death via a FAK-dependent mechanism.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anoikis*
  • Apoptosis
  • Caspase 8 / metabolism*
  • Cell Adhesion / genetics
  • Cell Line, Tumor
  • Enzyme Activation
  • Esophageal Neoplasms / metabolism*
  • Extracellular Matrix / metabolism
  • Fluorescent Antibody Technique, Indirect
  • Focal Adhesion Kinase 1 / metabolism*
  • Humans
  • Immunoblotting
  • Immunoprecipitation
  • Integrin beta1 / metabolism*
  • Mutation*
  • Phosphorylation
  • Signal Transduction / genetics
  • Tumor Suppressor Protein p53 / genetics*

Substances

  • Integrin beta1
  • TP53 protein, human
  • Tumor Suppressor Protein p53
  • Focal Adhesion Kinase 1
  • PTK2 protein, human
  • CASP8 protein, human
  • Caspase 8