Patterns of cyclooxygenase-1 and -2 expression in human gliomas in vivo.
Cyclooxygenases (COX, prostaglandin endoperoxide synthases, PGG/H synthases) are potent mediators of inflammation. While COX-1 is constitutively expressed in a wide range of tissues, COX-2 is cytokine inducible. Although COX-1 expression is observed in normal tissue, enhanced COX-2 expression has been attributed a key role in the development of edema, impeding blood flow and immunomodulation observed in pathologically altered tissues. Here, we have analyzed the expression of COX-1 and COX-2 in 50 gliomas and 10 control brains with no neuropathological alterations by immunohistochemistry; 22 glioblastoma multiforme, 9 anaplastic astrocytomas, 5 protoplasmic astrocytomas, 1 gemistocytic astrocytoma and 13 fibrillary astrocytomas were included in the study. Compared with control brains, accumulation of COX-1 was detected in 20-50% of all cells in both low- and high-grade gliomas. Double-labeling experiments revealed COX-1 expression in subsets of macrophages/microglial cells within the tumor parenchyma and in areas of infiltrative tumor growth. Of the COX-1-positive cells, 90% expressed MHC class II antigens. No COX-1 immunoreactivity was observed in tumor cells. COX-2-positive cells accumulated in tumor cells and in single macrophages/microglial cells in the immediate vicinity of necroses. Further studies are required to determine whether COX-2 is involved in the development of necrosis or, more likely, whether COX-2 is a part of the tumor tissue response to necrosis.
Deininger
M H
MH
Institute of Brain Research, University of Tuebingen Medical School, Germany. hirnforschung@uni-tuebingen.de
Weller
M
M
Streffer
J
J
Mittelbronn
M
M
Meyermann
R
R
D000328:Adult; D000368:Aged; D001921:Brain / Q000201:enzymology* / Q000473:pathology; D001932:Brain Neoplasms / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D005260:Female; D005904:Glial Fibrillary Acidic Protein / Q000032:analysis; D005909:Glioblastoma / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007527:Isoenzymes / Q000032:analysis / Q000096:biosynthesis*; D008297:Male; D008565:Membrane Proteins; D008875:Middle Aged; D009336:Necrosis; D011451:Prostaglandin-Endoperoxide Synthases / Q000032:analysis / Q000096:biosynthesis*
D005904:Glial Fibrillary Acidic Protein; D007527:Isoenzymes; D008565:Membrane Proteins; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; C496511:PTGS1 protein, human; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases