Strong evidence for up-regulation of cyclooxygenase-1 in head and neck cancer.
BACKGROUND
Cyclooxygenase-1, in contrast to cyclooxygenase-2, is generally reported to be constitutively expressed as a housekeeping enzyme in many different tissues. A number of recently published reports, however, challenge the notion that cyclooxygenase-1 expression is invariably constitutive by demonstrating that this enzyme might be up-regulated under certain pathological conditions in, for example, breast or ovarian cancer cells. In this study we investigated the expression of cyclooxygenase-1 in head and neck tumours and compared it to the cyclooxygenase-1 expression levels in normal oropharyngeal epithelial cells.


METHODS
Paraffin-embedded pretreatment biopsies were obtained from head and neck tumour patients (n = 35). In addition, samples of normal oropharyngeal mucosa were taken from patients (n = 12) undergoing routine tonsillectomy. Cyclooxygenase-1 expression levels were determined by immunohistochemistry, Western blotting and real-time RT-PCR in cancerous tissue versus normal mucosa.


RESULTS
Immunohistochemistry revealed overexpression of cyclooxygenase-1 in tumour biopsies compared to normal mucosa. Cyclooxygenase-1 was highly synthesized in the cytoplasm of neoplastic cells while significantly lower levels were detectable in normal mucosal cells. Western blotting and real-time RT-PCR also demonstrated higher cyclooxygenase-1 levels in tumour specimens compared to normal tissue samples.


CONCLUSIONS
In this study we show for the first time that cyclooxygenase-1 is overexpressed in head and neck cancer cells compared to epithelial cells of normal mucosa.
Erovic
B M
BM
Department of Otorhinolaryngology, The Medical University of Vienna, Austria.
Woegerbauer
M
M
Pammer
J
J
Selzer
E
E
Grasl
M Ch
MCh
Thurnher
D
D
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015153:Blotting, Western; D002294:Carcinoma, Squamous Cell / Q000201:enzymology*; D051545:Cyclooxygenase 1 / Q000378:metabolism*; D004847:Epithelial Cells / Q000201:enzymology; D005260:Female; D006258:Head and Neck Neoplasms / Q000201:enzymology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009960:Oropharynx / Q000201:enzymology; D015854:Up-Regulation
D051545:Cyclooxygenase 1