Repression of let-7a cluster prevents adhesion of colorectal cancer cells by enforcing a mesenchymal phenotype in presence of liver inflammation

Cell Death Dis. 2018 May 1;9(5):489. doi: 10.1038/s41419-018-0477-1.

Abstract

The liver is the most common site of metastasis in patients with colorectal cancer, and colorectal cancer liver metastasis (CRLM) is associated with poor rates of survival. However, CRLM occurs infrequently in livers exhibiting signs of hepatitis or cirrhosis, suggesting a role for inflammation in attenuating CRLM. The molecular mechanisms driving this phenomenon remain unclear. The aim of this study was to confirm the mechanism by which liver inflammation inhibits CRLM. We used BALB/c animal models of inflammatory liver diseases to confirm that liver inflammation inhibits CRLM, and then elucidated the molecular mechanisms governing that process. Out data showed that liver inflammation induces IFN-γ expression, which then downregulates expression of the let-7a cluster through IRF-1 in colorectal cancer cells. Finally, we showed that modulation of let-7a expression regulated the epithelial-mesenchymal transition in colorectal cancer cell lines, and inhibited their capacity to metastasize in vivo. Cumulatively, we clarified the critical role played by the IFN-γ/IRF-1/let-7a cluster/EMT pathway in regulating the spread of circulating colorectal cancer cells to the liver, and highlighted the critical role that the hepatitis microenvironment plays in modulating that process.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Adhesion*
  • Chemical and Drug Induced Liver Injury / genetics
  • Chemical and Drug Induced Liver Injury / metabolism*
  • Chemical and Drug Induced Liver Injury / pathology
  • Colorectal Neoplasms / genetics
  • Colorectal Neoplasms / metabolism*
  • Colorectal Neoplasms / pathology
  • Disease Models, Animal
  • Epithelial-Mesenchymal Transition*
  • Gene Expression Regulation, Neoplastic
  • HT29 Cells
  • Humans
  • Interferon Regulatory Factor-1 / genetics
  • Interferon Regulatory Factor-1 / metabolism
  • Interferon-gamma / metabolism
  • Liver Neoplasms / genetics
  • Liver Neoplasms / metabolism*
  • Liver Neoplasms / prevention & control
  • Liver Neoplasms / secondary
  • Male
  • Mice, Inbred BALB C
  • MicroRNAs / genetics
  • MicroRNAs / metabolism*
  • Signal Transduction
  • Tumor Microenvironment

Substances

  • IFNG protein, mouse
  • Interferon Regulatory Factor-1
  • Irf1 protein, mouse
  • MicroRNAs
  • mirnlet7 microRNA, human
  • mirnlet7 microRNA, mouse
  • Interferon-gamma