Overexpression of nicotinamide N-methyltransferase in gastric cancer tissues and its potential post-translational modification.
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.
Lim
Bo-Hyun
BH
Department of Microbiology, College of Natural Science, Gyeongsang National University, Jinju 600-701, Korea.
Cho
Bok-Im
BI
Kim
Yu Na
YN
Kim
Jae Won
JW
Park
Soon-Tae
ST
Lee
Chang-Won
CW
D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis; D014408:Biomarkers, Tumor / Q000302:isolation & purification; D015153:Blotting, Western / Q000379:methods; D002277:Carcinoma / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D050903:Nicotinamide N-Methyltransferase / Q000276:immunology / Q000378:metabolism*; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D020543:Proteome / Q000032:analysis; D013274:Stomach Neoplasms / Q000378:metabolism*; D013276:Stomach Ulcer / Q000378:metabolism; D014018:Tissue Distribution
D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor; D020543:Proteome; C494406:NNMT protein, human; D050903:Nicotinamide N-Methyltransferase