Differential expression of nitric oxide synthase in human stomach cancer.
The level of expression and cellular localization of isoenzymes of nitric oxide synthase (NOS) was detected in human stomach tumor tissues. Tumor tissues showed 70% higher activity of NOS than that of normal tissues (P < 0.01). Poorly differentiated adenocarcinoma tend to have higher activity (P < 0.05) than well differentiated and moderately differentiated tumor tissues. Aminoguanidine (AG), 2-amino-5,6-dihydro-6-methyl-4H-1,3-thiazine (AMT), NG-monomethyl-L-arginine (L-NMMA), and Nomega-nitro-L-arginine (L-NNA) inhibited NOS activity in tumor tissues by 18, 14, 11 and 13%, respectively. The TNF-alpha mRNA expression was correlated with the inducible NOS (iNOS) level, which was high in adenocarcinomas and low in normal tissues. Tumor tissues showed higher expression of iNOS in gland epithelial cells but the level of eNOS was significantly decreased with an exception of concentrated localization in the proliferating capillary endothelium. These results revealed that isoforms of NOS might contribute differentially to growth and progression of human stomach tumor.
Koh
E
E
Department of Genetic Engineering, Sungkyunkwan University, Suwon, South Korea.
Noh
S H
SH
Lee
Y D
YD
Lee
H Y
HY
Han
J W
JW
Lee
H W
HW
Hong
S
S
D000328:Adult; D000368:Aged; D005260:Female; D006146:Guanidines / Q000494:pharmacology; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D019001:Nitric Oxide Synthase / Q000235:genetics / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000201:enzymology* / Q000473:pathology
D006146:Guanidines; D012333:RNA, Messenger; C496319:NOS2 protein, human; C496314:NOS3 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C004479:pimagedine