Inducible nitric oxide synthase expression in human colorectal cancer: correlation with tumor angiogenesis.
To investigate the potential involvement of the nitric oxide (NO) pathway in colorectal carcinogenesis, we correlated the expression and the activity of inducible nitric oxide synthase (iNOS) with the degree of tumor angiogenesis in human colorectal cancer. Tumor samples and adjacent normal mucosa were obtained from 46 surgical specimens. Immunohistochemical expression of iNOS, vascular endothelial growth factor (VEGF), and CD31 was analyzed on paraffin-embedded tissue sections. iNOS activity and cyclic GMP levels were assessed by specific biochemical assays. iNOS protein expression was determined by Western blot analysis. iNOS and VEGF mRNA levels were evaluated using Northern blot analysis. Both iNOS and VEGF expressions correlated significantly with intratumor microvessel density (r(s) = 0.31, P = 0.02 and r(s) = 0.67, P < 0.0001, respectively). A significant correlation was also found between iNOS and VEGF expression (P = 0.001). iNOS activity and cyclic GMP production were significantly higher in the cancer specimens than in the normal mucosa (P < 0.0001 and P < 0.0001, respectively), as well as in metastatic tumors than in nonmetastatic ones (P = 0.002 and P = 0.04, respectively). Western and Northern blot analyses confirmed the up-regulation of the iNOS protein and gene in the tumor specimens as compared with normal mucosa. NO seems to play a role in colorectal cancer growth by promoting tumor angiogenesis.
Cianchi
Fabio
F
Department of General Surgery, Medical School, University of Florence, Florence, Italy. cianchif@mail.unifi.it
Cortesini
Camillo
C
Fantappiè
Ornella
O
Messerini
Luca
L
Schiavone
Nicola
N
Vannacci
Alfredo
A
Nistri
Silvia
S
Sardi
Iacopo
I
Baroni
Gianna
G
Marzocca
Cosimo
C
Perna
Federico
F
Mazzanti
Roberto
R
Bechi
Paolo
P
Masini
Emanuela
E
D015703:Antigens, CD / Q000378:metabolism; D015152:Blotting, Northern; D015179:Colorectal Neoplasms / Q000098:blood supply* / Q000201:enzymology / Q000235:genetics* / Q000473:pathology; D006152:Cyclic GMP / Q000378:metabolism; D015232:Dinoprostone / Q000378:metabolism; D016228:Endothelial Growth Factors / Q000032:analysis / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D036341:Intercellular Signaling Peptides and Proteins / Q000032:analysis / Q000235:genetics; D008222:Lymphokines / Q000032:analysis / Q000235:genetics; D009389:Neovascularization, Pathologic / Q000235:genetics / Q000473:pathology*; D019001:Nitric Oxide Synthase / Q000235:genetics* / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D014158:Transcription, Genetic; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D015703:Antigens, CD; D016228:Endothelial Growth Factors; D036341:Intercellular Signaling Peptides and Proteins; D008222:Lymphokines; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; C496319:NOS2 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D006152:Cyclic GMP; D015232:Dinoprostone