1. Academic Validation
  2. Association of the epithelial-to-mesenchymal transition phenotype with responsiveness to the p21-activated kinase inhibitor, PF-3758309, in colon cancer models

Association of the epithelial-to-mesenchymal transition phenotype with responsiveness to the p21-activated kinase inhibitor, PF-3758309, in colon cancer models

  • Front Pharmacol. 2013 Mar 28;4:35. doi: 10.3389/fphar.2013.00035.
Todd M Pitts 1 Gillian N Kulikowski Aik-Choon Tan Brion W Murray John J Arcaroli John J Tentler Anna Spreafico Heather M Selby Maria I Kachaeva Kelly L McPhillips Blair C Britt Erica L Bradshaw-Pierce Wells A Messersmith Marileila Varella-Garcia S Gail Eckhardt
Affiliations

Affiliation

  • 1 Division of Medical Oncology, University of Colorado Anschutz Medical Campus Aurora, CO, USA.
Abstract

The p21-activated kinase (PAK) family of serine/threonine kinases, which are overexpressed in several Cancer types, are critical mediators of cell survival, motility, mitosis, transcription, and translation. In the study presented here, we utilized a panel of colorectal Cancer (CRC) cell lines to identify potential biomarkers of sensitivity or resistance that may be used to individualize therapy to the PAK inhibitor PF-03758309. We observed a wide range of proliferative responses in the CRC cell lines exposed to PF-03758309, this response was recapitulated in other phenotypic assays such as anchorage-independent growth, three-dimensional (3D) tumor spheroid formation, and migration. Interestingly, we observed that cells most sensitive to PF-03758309 exhibited up-regulation of genes associated with a mesenchymal phenotype (CALD1, VIM, ZEB1) and cells more resistant had an up-regulation of genes associated with an epithelial phenotype (CLDN2, CDH1, CLDN3, CDH17) allowing us to derive an epithelial-to-mesenchymal transition (EMT) gene signature for this agent. We assessed the functional role of EMT-associated genes in mediating responsiveness to PF-3758309, by targeting known genes and transcriptional regulators of EMT. We observed that suppression of genes associated with the mesenchymal phenotype conferred resistance to PF-3758309, in vitro and in vivo. These results indicate that PAK inhibition is associated with a unique response phenotype in CRC and that further studies should be conducted to facilitate both patient selection and rational combination strategies with these agents.

Keywords

EMT; PAK; PF-3758309; colorectal cancer; intrinsic resistance.

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