Comparative Proteomics Analysis of Barrett Metaplasia and Esophageal Adenocarcinoma Using Two-dimensional Liquid Mass Mapping

Abstract

Esophageal adenocarcinoma, currently the seventh leading cause of cancer-related death, has been associated with the presence of Barrett metaplasia. The malignant potential of Barrett metaplasia is evidenced by ultimate progression of this condition to invasive adenocarcinoma. We utilized liquid phase separation of proteins with chromatofocusing in the first dimension and nonporous reverse phase HPLC in the second dimension followed by ESI-TOF mass spectrometry to identify proteins differentially expressed in six Barrett metaplasia samples as compared with six esophageal adenocarcinoma samples; all six Barrett samples were obtained from the identical six patients from whom we obtained the esophageal adenocarcinoma tissue. Approximately 300 protein bands were detected by mass mappings, and 38 differentially expressed proteins were identified by LC-MS/MS. The false positive rates of the peptide identifications were evaluated by reversed database searching. Among the proteins that were identified, Rho GDP dissociation inhibitor 2, ␣-enolase, Lamin A/C, and nucleoside-diphosphate kinase A were demonstrated to be up-regulated in both mRNA and protein expression in esophageal adenocarcinomas relative to Barrett metaplasia. Candidate proteins were examined at the mRNA level using high density oligonucleotide microarrays. The cellular expression patterns were verified in both esophageal adenocarcinomas and in Barrett metaplasia by immunohistochemistry. These differentially expressed proteins may have utility as useful candidate markers of esophageal adenocarcinoma. Molecular & Cellular Proteomics 6:987-999, 2007.Esophageal adenocarcinoma is increasing rapidly in Western countries and is currently the seventh leading cause of cancer-related death (1). Esophageal adenocarcinoma has been associated with the presence of Barrett metaplasia, a condition in which the normal squamous epithelium of the esophagus is replaced by columnar epithelium. The malignant potential of this condition is evidenced by the progression of Barrett metaplasia to low grade dysplasia, high grade dysplasia, and ultimately to invasive adenocarcinoma. The risk of developing adenocarcinoma is 30 -125 times higher in people who have Barrett metaplasia than people who do not. The prognosis of patients with esophageal adenocarcinoma remains poor with overall 5-year survival rates of only 5-15% (1). Unfortunately patients often present with regionally advanced disease (2). Given the poor prognosis associated with esophageal adenocarcinoma, it is imperative to improve our understanding of the tumorigenesis and the factors associated with increased risk. It is possible that therapeutic targets or protein markers can be identified that will ultimately facilitate improved patient survival.Proteomics technologies have been used for the identification of candidate markers for early cancer detection (3). The global analysis of protein expression complements genomics analyses. For example, proteomics analysis may provide further insight into post-translational mod...

Quantitative Shotgun Proteomics Unveils Candidate Novel Esophageal Adenocarcinoma (EAC)-specific Proteins

“…The sample number was therefore based on previous esophageal discovery-phase proteomic studies or studies in similar tissue types (19–22), and the availability of high quality clinical material.…”

Comparative Proteomics Approach to Screening of Potential Diagnostic and Therapeutic Targets for Oral Squamous Cell Carcinoma

“…Some of these proteins, such as SCC1, stathmin, calmodulin, fatty-acid binding protein, glutathione S transferase, galectin-7, calgranulin B, tropomyosin, Annexin A1, and nucleoside-diphosphate kinase A, have been reported to be associated with OSCC in previous studies but without clinical validation and in-depth functional research (6 -8). Furthermore eight of the altered expressed proteins, such as Rho GDP dissociation inhibitor 1 (19), proteasome activator complex subunit 2 (20), S100 family proteins (21), translationally controlled tumor protein (22), peroxiredoxin-4 (23), RACK1, calcium-binding protein P22, and protein DJ-1 have been observed to be differentially expressed in cancers from other origins but not previously in OSCC. However, most of these altered proteins have been found to be involved in multiple cellular pathways related to carcinogenesis (e.g.…”

Current advances in esophageal cancer proteomics

“…The insight into potential mechanisms underlying the progression from Barrett's metaplasia to EAC was gained by Zhao et al [81], who found that Rho GDP dissociation inhibitor 2, alpha-enolase, lamin A/C, and nucleoside-diphosphate kinase A were upregulated at both mRNA and protein levels in EAC compared to Barrett's metaplasia. The results suggest that the identified proteins play a role in EAC development and may be candidate biomarkers of the progression from Barrett's metaplasia to EAC.…”