Proteomic expression analysis of colorectal cancer by two‐dimensional differential gel electrophoresis

Abstract

The identification of specific protein markers for colorectal cancer would provide the basis for early diagnosis and detection, as well as clues for understanding the molecular mechanisms governing cancer progression. In this report, we describe the proteomic analysis of the samples of colorectal cancer corresponding to seven patients. We have used the highly sensitive two-dimensional differential gel electrophoresis (2-D DIGE) coupled with mass spectrometry (MS) for the identification of proteins differentially expressed in tumoral and neighboring normal mucosa. We have detected differences in abundance of 52 proteins with statistical variance of the tumor versus normal spot volume ratio within the 95th confidence level (Student's t-test; p < 0.05). Forty-one out of 52 analyzed proteins were unambiguously identified by matrix-assisted laser desorption/ionization-time of flight MS coupled with database interrogation as being differentially expressed in colorectal cancer. An ontology analysis of these proteins revealed that they were mainly involved in regulation of transcription (synovial sarcoma X5 protein, metastasis-associated protein 1), cellular reorganization and cytoskeleton (cytokeratins, vimentin, beta actin), cell communication and signal transduction (annexins IV and V, relaxin, APC), and protein synthesis and folding (heat shock protein 60, calreticulin, cathepsin D, RSP4) among others. Preliminary studies demonstrated that the differentially expressed proteins found by 2-D DIGE could be confirmed and validated by immunoblotting and immunohistochemistry analyses in those few cases where antibodies were available. We believe that the incorporation of more samples and new datasets will permit the definition of a collection of proteins with a potential interest as biomarkers for colorectal cancer.

Fra‐1 regulates vimentin during Ha‐RAS‐induced epithelial mesenchymal transition in human colon carcinoma cells

“…Evidence exist that vimentin is increased in tumors from patients with colorectal cancer. 25 For the first time, we provide evidence that vimentin is a protein differentially regulated between Ha-RAS and Ki-RAS, leading to Ha-RAS specific induction of migrative phenotype and eventually EMT. Vimentin regulation seems to be partly done through the MAPK-ERK pathway.…”

Annexin I Regulates SKCO-15 Cell Invasion by Signaling through Formyl Peptide Receptors

“…The classic bacterial derived FPR-1 ligand, fMLP, has also been shown to activate FPRL-1, albeit with significantly reduced affinity (79). Other infectious agent-derived agonists include human immunodeficiency virus, type 1 envelope proteins and the Helicobacter pylori peptide Hp (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). WKYMVm is an agonist for all three nFPR family members that were derived from peptide libraries (80,81).…”

Proteomics-based Validation of Genomic Data

“…Some of these genes have been proposed as candidate cancer biomarkers (10 -12). More recently a number of proteomic studies have also addressed the identification of potential targets in CRC (13)(14)(15).…”