Original Article
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World J Gastroenterol. Mar 21, 2012; 18(11): 1216-1228
Published online Mar 21, 2012. doi: 10.3748/wjg.v18.i11.1216
Proteomic analysis of gastric cancer and immunoblot validation of potential biomarkers
Nina Kočevar, Federico Odreman, Alessandro Vindigni, Snježana Frković Grazio, Radovan Komel
Nina Kočevar, Radovan Komel, Medical Centre for Molecular Biology, Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Ljubljana 1000, Slovenia
Federico Odreman, Alessandro Vindigni, International Centre for Genetic Engineering and Biotechnology Trieste, AREA Science Park, Trieste 34149, Italy
Snježana Frković Grazio, Department of Obstetrics and Gynecology, Department of Gynecological Pathology and Cytology, University Clinical Hospital Ljubljana, Ljubljana 1000, Slovenia
Author contributions: Komel R designed and supervised the research; Vindigni A supervised some of the mass spectrometry; Kočevar N performed most proteomic experiments; Odreman F contributed part of the mass spectrometry analysis; and Grazio SF provided tissue samples and clinical data.
Supported by Research grant, No. P1-0104-0386; and the Junior Researcher Grant, No. 1000-07-310086, awarded to Kočevar N, both from the Slovenian Research Agency
Correspondence to: Radovan Komel, PhD, Professor of Bichemistry, Medical Centre for Molecular Biology, Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, Ljubljana 1000, Slovenia. radovan.komel@mf.uni-lj.si
Telephone: +386-1-5437662 Fax: +386-1-5437641
Received: April 16, 2011
Revised: May 26, 2011
Accepted: June 3, 2011
Published online: March 21, 2012

AIM: To search for and validate differentially expressed proteins in patients with gastric adenocarcinoma.

METHODS: We used two-dimensional gel electrophoresis and mass spectrometry to search for differentially expressed proteins in patients with gastric adenocarcinoma. A set of proteins was validated with immunoblotting.

RESULTS: We identified 30 different proteins involved in various biological processes: metabolism, development, death, response to stress, cell cycle, cell communication, transport, and cell motility. Eight proteins were chosen for further validation by immunoblotting. Our results show that gastrokine-1, 39S ribosomal protein L12 (mitochondrial precursor), plasma cell-induced resident endoplasmic reticulum protein, and glutathione S-transferase mu 3 were significantly underexpressed in gastric adenocarcinoma relative to adjacent non-tumor tissue samples. On the other hand, septin-2, ubiquitin-conjugating enzyme E2 N, and transaldolase were significantly overexpressed. Translationally controlled tumor protein was shown to be differentially expressed only in patients with cancer of the gastric cardia/esophageal border.

CONCLUSION: This work presents a set of possible diagnostic biomarkers, validated for the first time. It might contribute to the efforts of understanding gastric cancer carcinogenesis.

Keywords: Two-dimensional gel electrophoresis, Mass spectrometry, Gastric adenocarcinoma, Proteome, Biomarkers