Investigation of the role of tyrosine kinase receptor EPHA3 in colorectal cancer

Elena Andretta,Elena Andretta,Irati Macaya,Irati Macaya,Arthur Brown,Santiago Ramon Y Cajal,Josipa Bilic,Josipa Bilic,Rocio Nieto,Lizbeth M Jimenez-Flores,Priscila Guimarães De Marcondes,Priscila Guimarães De Marcondes,Diego Arango,Diego Arango,Simo Schwartz,Simo Schwartz,Simo Schwartz,Stefania Landolfi,Fernando Cartón-García,Fernando Cartón-García,Higinio Dopeso,Higinio Dopeso,Águeda Martínez-Barriocanal,Águeda Martínez-Barriocanal,Paulo Rodrigues,Paulo Rodrigues,Sarah Bazzocco,Sarah Bazzocco

doi:10.1038/srep41576

Abstract

EPH signaling deregulation has been shown to be important for colorectal carcinogenesis and genome-wide sequencing efforts have identified EPHA3 as one of the most frequently mutated genes in these tumors. However, the role of EPHA3 in colorectal cancer has not been thoroughly investigated. We show here that ectopic expression of wild type EPHA3 in colon cancer cells did not affect their growth, motility/invasion or metastatic potential in vivo. Moreover, overexpression of mutant EPHA3 or deletion of the endogenous mutant EPHA3 in colon cancer cells did not affect their growth or motility. EPHA3 inactivation in mice did not initiate the tumorigenic process in their intestine, and had no effects on tumor size/multiplicity after tumor initiation either genetically or pharmacologically. In addition, immunohistochemical analysis of EPHA3 tumor levels did not reveal associations with survival or clinicopathological features of colorectal cancer patients. In conclusion, we show that EPHA3 does not play a major role in colorectal tumorigenesis. These results significantly contribute to our understanding of the role of EPH signaling during colorectal carcinogenesis, and highlighting the need for detailed functional studies to confirm the relevance of putative cancer driver genes identified in sequencing efforts of the cancer genome.

Highlights

EPH signaling deregulation has been shown to be important for colorectal carcinogenesis and genomewide sequencing efforts have identified EPHA3 as one of the most frequently mutated genes in these tumors
Despite the evidence from the genetic screens, we found that overexpression of wild type or mutant EPHA3 did not affect the growth of colon cancer cells
EPH signaling has been shown to regulate the proliferative activity in the normal intestinal epithelium and maintain proliferating cells confined to the crypts of Lieberkühn[7,32]

Summary

Introduction

EPH signaling deregulation has been shown to be important for colorectal carcinogenesis and genomewide sequencing efforts have identified EPHA3 as one of the most frequently mutated genes in these tumors. We show that EPHA3 does not play a major role in colorectal tumorigenesis These results significantly contribute to our understanding of the role of EPH signaling during colorectal carcinogenesis, and highlighting the need for detailed functional studies to confirm the relevance of putative cancer driver genes identified in sequencing efforts of the cancer genome. Additional studies have confirmed the presence of recurrent EPHA3 mutations in colorectal tumors[12,13] that are distributed throughout the coding sequence of EPHA3 (Supplementary Figure 1) and that have been shown to disrupt EPHA3 signaling[16] Based on these genetic data, and the known importance of EPH signaling in colorectal cancer, EPHA3 inactivation would be expected to significantly contribute to the progression of colorectal tumors. Our results indicate that EPHA3 inactivation is not an important step in the tumorigenic process of colorectal tumors, and highlights the need to functionally validate the findings of large exome/genome sequencing studies

Methods

Results

Conclusion