Exp Mol Med.  2006 Oct;38(5):455-465.

Overexpression of nicotinamide N-methyltransferase in gastric cancer tissues and its potential post-translational modification

• Lim BH
• Cho BI
• Kim YN
• Kim JW
• Park ST
• Lee CW

Abstract

Gastric cancer is one of the most common cancers worldwide. The purpose of this study was to find out potential markers for gastric cancer. Tumor and normal tissues from 152 gastric cancer cases were analyzed by two-dimensional gel electrophoresis (2-DE). The images of silver stained gels were analyzed and statistical analysis of spot intensities revealed that spot 4262 showed higher expression (5.7-fold increase) in cancer tissues than in normal tissues (P< 0.001). It was identified by peptide mass fingerprinting as nicotinamide N-methyltransferase (NNMT). A monoclonal antibody with a detection limit down to 10 ng was produced against NNMT in mouse. Using the prepared monoclonal antibody, western blot analysis of NNMT was performed for gastric tissues from 15 gastric cancer patients and two gastric ulcer patients. The results corroborated those of 2-DE experiments. A single spot was detected in gastric ulcer tissues while four to five spots were detected in gastric cancer tissues. In cancer tissues, two additional spots of acidic and basic form were mainly detected on 2-DE gels. This suggests that NNMT receives a post-translational modification in cancer- specific manner.

Keyword

electrophoresis, gel, two-dimensional; nicotinamide N-methyltransferase; protein processing, post- translational; proteomics; stomach neoplasms

MeSH Terms

Tumor Markers, Biological/isolation & purification
Tissue Distribution
Stomach Ulcer/metabolism
Stomach Neoplasms/*metabolism
Proteome/analysis
*Protein Processing, Post-Translational
Phosphorylation
Nicotinamide N-Methyltransferase/immunology/*metabolism
Mice, Inbred BALB C
Mice
Humans
Carcinoma/*metabolism
Blotting, Western/methods
Antibodies, Monoclonal/biosynthesis
Animals