Gene trapping identifies chloride channel 4 as a novel inducer of colon cancer cell migration, invasion and metastases

Br J Cancer. 2010 Feb 16;102(4):774-82. doi: 10.1038/sj.bjc.6605536. Epub 2010 Jan 19.

Abstract

Background: To date, there are few reports on gene products contributing to colon cancer progression.

Methods: We used a gene trap comprised of an enhanced retroviral mutagen (ERM) cassette that includes a tetracycline-responsive promoter upstream of a haemagglutinin (HA) tag and a splice donor site. Integration of the ERM within an endogenous gene yields a tetracycline-regulated HA-tagged transcript. We transduced RKO colon cancer cells expressing a tetracycline trans-activator-off with the ERM-encoding retrovirus and screened for enhanced migration.

Results: One clone showed fivefold enhanced migration with tetracycline withdrawal. Rapid amplification of cDNA ends identified the trapped gene as the chloride channel 4 (CLCN4) exchanger. Stable expression of a CLCN4 cDNA enhanced motility, whereas cells knocked down or null for this transcript showed reduced migration/invasion. CLCN4-overexpressing RKO colon cancer cells were more resistant than controls to proton load-induced cytotoxicity, consistent with the H(+)-extruding function of this antiporter. Intra-splenic delivery of RKO-CLCN4 transfectants, but not controls, yielded liver metastases, and transcript levels were higher in colon cancer metastases to the liver when compared with primary tumours.

Conclusions: CLCN4 is a novel driver of colon cancer progression.

Publication types

  • Research Support, N.I.H., Extramural
  • Validation Study

MeSH terms

  • Adenocarcinoma / genetics
  • Adenocarcinoma / pathology*
  • Animals
  • Cell Movement / genetics*
  • Cells, Cultured
  • Chloride Channels / genetics
  • Chloride Channels / isolation & purification
  • Chloride Channels / physiology*
  • Cloning, Molecular / methods
  • Colonic Neoplasms / genetics
  • Colonic Neoplasms / pathology*
  • Disease Progression
  • HCT116 Cells
  • Humans
  • Liver Neoplasms / genetics
  • Liver Neoplasms / secondary
  • Mice
  • Mice, Nude
  • Neoplasm Invasiveness
  • Neoplasm Metastasis
  • Neoplasm Transplantation
  • Transplantation, Heterologous

Substances

  • CLCN4 protein, human
  • Chloride Channels