Caspase-1 is a novel target of p63 in tumor suppression

Cell Death Dis. 2013 May 23;4(5):e645. doi: 10.1038/cddis.2013.175.

Abstract

p63 is a p53 family transcription factor, which besides unique roles in epithelial development, shares tumor suppressive activity with its homolog p53. The p63 gene has different transcriptional start sites, which generate two N-terminal isoforms (transactivation domain (TA)p63 and amino terminal truncated protein(ΔN)p63); in addition alternative splicing at the 5'-end give rise to at least five C-terminal isoforms. This complexity of gene structure has probably fostered the debate and controversy on p63 function in cancer, with TP63-harboring two distinctive promoters, codifying for the TAp63 and ΔNp63 isoforms, and having discrete functions. However, ΔNp63 also drives expression of target genes that have a relevant role in cancer and metastasis. In this study, we identified a novel p63 transcriptional target, caspase-1. Caspase-1 is proinflammatory caspase, which functions in tumor suppression. We show that both p63 isoforms promote caspase-1 expression by physical binding to its promoter. Consistent with our in vitro findings, we also identified a direct correlation between p63 and caspase-1 expression in human cancer data sets. In addition, survival estimation analysis demonstrated that functional interaction between p63 and caspase-1 represents a predictor of positive survival outcome in human cancers. Overall, our data report a novel p63 target gene involved in tumor suppression, and the clinical analysis underlines the biological relevance of this finding and suggests a further clinically predictive biomarker.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Caspase 1 / genetics
  • Caspase 1 / metabolism*
  • Cell Line
  • HEK293 Cells
  • Humans
  • Promoter Regions, Genetic
  • Protein Binding
  • Protein Isoforms / genetics
  • Protein Isoforms / metabolism
  • RNA, Messenger / metabolism
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*
  • Transcriptional Activation
  • Tumor Suppressor Proteins / genetics
  • Tumor Suppressor Proteins / metabolism*

Substances

  • Protein Isoforms
  • RNA, Messenger
  • TP63 protein, human
  • Transcription Factors
  • Tumor Suppressor Proteins
  • Caspase 1