A Quantitative Proteomic Approach of the Different Stages of Colorectal Cancer Establishes OLFM4 as a New Nonmetastatic Tumor Marker

Abstract

Expression profiles represent new molecular tools that are useful to characterize the successive steps of tumor progression and the prediction of recurrence or chemotherapy response. In this study, we have used quantitative proteomic analysis to compare different stages of colorectal cancer. A combination of laser microdissection, OFFGEL separation, iTRAQ labeling, and MALDI-TOF/TOF MS was used to explore the proteome of 28 colorectal cancer tissues. Two software packages were used for identification and quantification of differentially expressed proteins: Protein Pilot and iQuantitator. Based on ϳ1,190,702 MS/MS spectra, a total of 3138 proteins were identified, which represents the largest database of colorectal cancer realized to date and demonstrates the value of our quantitative proteomic approach. In this way, individual protein expression and variation have been identified for each patient and for each colorectal dysplasia and cancer stage (stages I-IV). A total of 555 proteins presenting a significant fold change were quantified in the different stages, and this differential expression correlated with immunohistochemistry results reported in the Human Protein Atlas database. To identify a candidate biomarker of the early stages of colorectal cancer, we focused our study on secreted proteins. In this way, we identified olfactomedin-4, which was overexpressed in adenomas and in early stages of colorectal tumors. This early stage overexpression was confirmed by immunohistochemistry in 126 paraffin-embedded tissues. Our results also indicate that OLFM4 is regulated by the Ras-NF-B2 path-

Plasma olfactomedin 4 level in peripheral blood and its association with clinical features of breast cancer

“…The results from the present study indicated that plasma OLFM4 levels in breast cancer patients were associated with histological tumor differentiation. High plasma OLFM4 levels were detected in patients with high histological grade, which was consistent with data from previous studies on pancreatic (5) and gastric cancer (9,11).…”

“…Research has demonstrated that OLFM4 is involved in regulation of cell apoptosis, where OLFM4 attenuates apoptosis induced by hydrogen peroxide and tumor necrosis factor-α, and also inhibits the release of cytochrome c and activation of caspase 3 and 9. OLFM4 protein in cells ultimately has an anti-apoptotic role when cells are treated with a combination of interferon (IFN) β and retinoic acid (5,6). Furthermore, OLFM4 exerts a regulatory role in the cell cycle in DNA synthesis and mitosis from the S to the G2/M phase (7).…”

“…Furthermore, OLFM4 exerts a regulatory role in the cell cycle in DNA synthesis and mitosis from the S to the G2/M phase (7). In 2011, Besson et al (5) analyzed colorectal tumor tissue at different stages by quantitative immunohistochemistry. It was found that OLFM4 is over-expressed in low-grade and high-grade adenoma tumor tissues, adenoma in situ, and stage I-II colorectal cancer tissues.…”

“…Using a mouse melanoma model, Park et al (9) observed that OLFM4 suppresses tumor growth and metastasis by downregulating Studies have shown relatively low levels of OLFM4 expression in normal tissues of several organs, including the stomach, colon and pancreas. Whereas, to varying degrees, upregulation of OLFM4 expression has been implicated in gastric, pancreatic, lung, colon, rectal, and head/neck squamous cell cancer (5,(10)(11)(12). A study observed that there was no OLFM4 expression prostate cancer tissue, with moderate expression in benign prostatic hyperplasia and high expression in normal prostate tissue (13).…”

Sorbitol Dehydrogenase Overexpression and Other Aspects of Dysregulated Protein Expression in Human Precancerous Colorectal Neoplasms: A Quantitative Proteomics Study

“…9 and 20). We therefore decided to explore the proteome of a relatively large series of these precancerous lesions (each with a paired sample of normal colon mucosa) using quantitative shotgun MS with the widely used iTRAQ 1 peptide labeling technique (21,22) and OFFGEL fractionation. Adenoma-related protein expression variations specific to the epithelial compartments of these lesions were identified with a novel approach, which involved comparing the human tissue proteome with that of colon epithelial cell lines.…”