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Assessment of Resistance to Tyrosine Kinase Inhibitors by an Interrogation of Signal Transduction Pathways by Antibody Arrays
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Assessment of Resistance to Tyrosine Kinase Inhibitors by an Interrogation of Signal Transduction Pathways by Antibody Arrays

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Src family tyrosine kinases-driven colon cancer cell invasion is induced by Csk membrane delocalization

A Sirvent1, C Bénistant, J Pannequin

  • 1CRBM, CNRS, UMR5237, Equipe Labellisée 'Ligue Nationale contre le Cancer', University of Montpellier 1 and 2, Montpellier, France.

Oncogene
|December 17, 2009
PubMed

Insights

Src family kinases (SFK) drive colorectal cancer (CRC) invasion through the mis-localization of C-terminal Src kinase (Csk). Impaired Csk membrane transport, linked to PAG downregulation, activates SFK in CRC cells.

Area of Science:

  • Oncology
  • Molecular Biology
  • Cell Biology

Background:

  • Src family kinases (SFK) are deregulated in colorectal cancer (CRC), promoting tumor growth and metastasis.
  • The precise mechanisms activating SFK in CRC remain unclear.
  • C-terminal Src kinase (Csk) is a negative regulator of SFK activity.

Purpose of the Study:

  • To elucidate the mechanism of SFK activation in colorectal cancer.
  • To investigate the role of Csk localization and its regulatory partners in CRC progression.

Main Methods:

  • Analysis of Csk and SFK levels and localization in CRC cells.
  • Functional assays assessing cell invasion upon manipulation of Csk and PAG expression.
  • Comparison of Csk-SFK interactions in CRC versus breast cancer cells.

Main Results:

  • Csk levels did not correlate with SFK activity; impaired Csk membrane translocation was observed in CRC cells.
  • Downregulation of Csk-binding protein (PAG) facilitated Csk cytoplasmic accumulation, enhancing SFK-driven invasion.
  • Restoring PAG expression inhibited SFK invasion in late-stage CRC cells, while its loss promoted invasion in early-stage CRC cells.
  • Csk mis-localization was specific to CRC, unlike in breast cancer cells where Csk-SFK coupling was evident.

Conclusions:

  • Csk mis-localization represents a novel mechanism for SFK oncogenic activation in colorectal cancer.
  • PAG plays a critical role in regulating Csk localization and SFK activity in CRC.
  • Targeting Csk localization could offer a therapeutic strategy for colorectal cancer.

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