BRAF status modulates Interelukin-8 expression through a CHOP-dependent mechanism in colorectal cancer

Commun Biol. 2020 Oct 1;3(1):546. doi: 10.1038/s42003-020-01263-y.

Abstract

Inflammation might substantially contribute to the limited therapeutic success of current systemic therapies in colorectal cancer (CRC). Amongst cytokines involved in CRC biology, the proinflammatory chemokine IL-8 has recently emerged as a potential prognostic/predictive biomarker. Here, we show that BRAF mutations and PTEN-loss are associated with high IL-8 levels in CRC models in vitro and that BRAF/MEK/ERK, but not PI3K/mTOR, targeting controls its production in different genetic contexts. In particular, we identified a BRAF/ERK2/CHOP axis affecting IL-8 transcription, through regulation of CHOP subcellular localization, and response to targeted inhibitors. Moreover, RNA Pol II and an open chromatin status in the CHOP-binding region of the IL-8 gene promoter cooperate towards increased IL-8 expression, after a selective BRAF inhibition. Overall, our data show that IL-8 production is finely and differentially regulated depending on the tumor genetic context and might be targeted for therapeutic purposes in molecularly defined subgroups of CRC patients.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blotting, Western
  • Cell Line, Tumor
  • Colorectal Neoplasms / metabolism*
  • Fluorescent Antibody Technique
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Interleukin-8 / metabolism*
  • Mitogen-Activated Protein Kinase Kinases / metabolism
  • Mutagenesis, Site-Directed
  • Proto-Oncogene Proteins B-raf / metabolism*
  • Proto-Oncogene Proteins B-raf / physiology
  • RNA Polymerase II / metabolism
  • Signal Transduction
  • Transcription Factor CHOP / metabolism*

Substances

  • CXCL8 protein, human
  • DDIT3 protein, human
  • Interleukin-8
  • Transcription Factor CHOP
  • BRAF protein, human
  • Proto-Oncogene Proteins B-raf
  • Mitogen-Activated Protein Kinase Kinases
  • RNA Polymerase II