The correlation between cyclooxygenase-2 expression and hepatocellular carcinogenesis.
Overexpression of cyclooxygenase 2 (COX-2) is associated with tumorigenesis in a number of human cancers. Recently, COX-2 overexpression has also been reported in hepatocellular carcinoma (HCC), especially in well-differentiated HCC. However, doubt has been cast on these claims concerning HCC. Here we show by Western blot analysis that COX-2 protein level is higher in the adjacent chronic hepatitis liver than in the tumors themselves. We also show, by immunohistochemical staining, that the mean intensity of COX-2 expression in cirrhotic liver specimens is significantly higher than in normal livers and in moderately-differentiated HCC. In addition, the frequency and level of expression of COX-2 in poorly differentiated HCC was similar to that of well-differentiated HCC. Nevertheless all types of HCC expressed more COX-2 than normal livers, and immunofluorescence staining showed cytoplasmic expression of COX-2 in 7 out of 8 human hepatoma cell lines. Collectively, our data suggest that both chemoprevention and chemotherapy of HCC by COX-2 specific inhibitors should be considered. Our data also suggest that COX-2 may play a role in the advanced stages as well as early stages of hepatocarcinogenesis.
Sung
Young Kwan
YK
Department of Immunology, School of Medicine, Kyungpook National University, Daegu 700-422, Korea.
Hwang
Sun Young
SY
Kim
Jin Oh
JO
Bae
Han Ik
HI
Kim
Jung-Chul
JC
Kim
Moon Kyu
MK
D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000201:enzymology* / Q000378:metabolism; D002454:Cell Differentiation; D002467:Cell Nucleus / Q000378:metabolism; D002908:Chronic Disease; D051546:Cyclooxygenase 2; D003593:Cytoplasm / Q000378:metabolism; D006505:Hepatitis / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000096:biosynthesis*; D008099:Liver / Q000378:metabolism; D008113:Liver Neoplasms / Q000201:enzymology*; D008565:Membrane Proteins; D008856:Microscopy, Fluorescence; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis*; D014407:Tumor Cells, Cultured
D007527:Isoenzymes; D008565:Membrane Proteins; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases