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Updated: Aug 18, 2025

Fluorescence-based Monitoring of PAD4 Activity via a Pro-fluorescence Substrate Analog
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Pals1 functions in redundancy with SMAP1 to inhibit Arf6 in order to prevent Rac1-dependent colorectal cancer cell

Julia Harms1, Simona Mareike Lüttgenau1, Christin Emming1

  • 1Medical Clinic D, Medical Cell Biology, University Hospital of Münster, Münster, Germany.

Cancer Gene Therapy
|December 9, 2022
PubMed

Insights

Colorectal cancer cells

Area of Science:

  • Cell biology
  • Molecular oncology
  • Cancer metastasis

Background:

  • Cell-cell adhesion loss and increased motility drive cancer metastasis.
  • Pals1 (Partitioning defective 1 homolog) downregulation in colorectal cancer enhances cell migration and metastasis via Arf6 and Rac1 activation.

Purpose of the Study:

  • To investigate the functional redundancy between SMAP1 and Pals1 in regulating Arf6 activity and cell migration in colorectal cancer.
  • To determine the clinical significance of SMAP1 and Pals1 alterations in colorectal cancer patient survival.

Main Methods:

  • Functional assays assessing cell migration and invasion.
  • Analysis of Arf6 and Rac1 activity.
  • Gene expression analysis in colorectal cancer cell lines and patient cohorts.
  • Genetic manipulation (deletion/inactivation) of SMAP1 and Pals1.

Main Results:

  • SMAP1 and Pals1 exhibit functional redundancy in controlling Arf6 activity and Rac1-dependent cell migration.
  • SMAP1 gene disruptions are frequent in microsatellite instable colorectal cancer.
  • Inactivation of both SMAP1 and Pals1 significantly increases Arf6/Rac1 activity, cell migration, and invasion.
  • Co-downregulation of SMAP1 and Pals1 in patients correlates with decreased survival.

Conclusions:

  • SMAP1 and Pals1 are redundant regulators of Arf6/Rac1 signaling, impacting colorectal cancer cell migration, invasion, and metastasis.
  • Combined loss of SMAP1 and Pals1 represents a potential biomarker for poor prognosis in colorectal cancer.

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