[Frontiers in Bioscience E5, 574-582, January 1, 2013]

Effect of genomic instability and mutations on the signaling pathways in colon cancer cells

Miao Cui1, Fei Ye2, Bo Jiang3, Peng Deng1, Xinying Wang3, Yong Jiang1, David Zhang2

1Department of Pathophysiology, Southern Medical University, Guangzhou 510515, China, 2Departments of Pathology, Mount Sinai School of Medicine, New York, NY 10029, USA, 1Department of Gastroenterology3, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China

TABLE OF CONTENTS

1. Abstract
2. Introduction
3. Materials and methods
3.1. Cell culture
3.2. Protein Pathway Array analysis
3.3. Antibodies used in this study
3.4. Signaling network analysis
4. Results
4.1. Genetic characteristics of colon cancer cell lines
4.2. Comparison of the protein expression between MSI and MSS cells
4.3. Comparison of the protein expression between K-RAS mutant cells and K-RAS wild type cells with MSS
4.4. Canonical pathways altered in MSI cells and K-RAS mutant cells
4.5. The interactive network in MSI cells
4.6. Effect of MSI and K-ras mutation on EGFR pathway
5. Discussion
6. Acknowledgements
7. References

1. ABSTRACT

Microsatellite instability (MSI) is present in about 15% of colorectal cancers and plays critical roles in the development and progression of these cancers. The goal of this study is to determine the global effect of microsatellite instability on the signaling pathways and network in colon cancer cells. We profiled the expression and phosphorylation of 110 proteins in six colon cancer cell lines by using Protein Pathway Array. The pathways and network constituted by these proteins were identified by using Ingenuity Pathway Analysis. Our results showed that 25 proteins and phosphoproteins change more than 1.5-fold between MSI and microsatellite stable (MSS) cells. Sixteen major pathways were affected in MSI cells, including p53 and 14-3-3β pathways, with p53 and HGF being the most important pathways. Finally, although the EGFR/K-RAS/MEK pathway was not affected in MSI cells, collateral pathways such as the p70S6K and p90RSK pathways were activated in MSI cells. Thus, suppression of the p53 pathway and activation of the HGF pathway in MSI cells may be critical in the tumorigenesis of MSI colorectal cancer.