Expression of cyclooxygenase-1 and -2 in naturally occurring squamous cell carcinomas in horses.
OBJECTIVE
To assess expression of cyclooxygenase (COX)-1 and -2 in naturally occurring squamous cell carcinomas (SCCs) and the analogous normal tissues in horses.


METHODS
Tissue samples collected from 3 conjunctival, 2 vulvar, 4 preputial, and 5 penile SCCs during surgical excision in 14 horses and from corresponding body regions (conjunctiva [n = 5 horses], vulva [2], prepuce [3], and penis [3]) in 5 horses euthanized for reasons unrelated to neoplasia.


METHODS
Tissue samples were snap frozen in liquid nitrogen and stored at -80 degrees C until analysis. Protein was extracted from the frozen tissues, and western blot analyses were performed. Nonneoplastic and abnormal tissues from each body region were run on the same blot, and blots were run in triplicate. Molecular-weight markers and COX-1 and 2 ovine standards (positive control samples) were run concurrently on the gels; negative control samples were not used.


RESULTS
All tissues, including the nonneoplastic and SCC tissues, expressed both COX-1 and -2 proteins.


CONCLUSIONS
Results indicated that the expression of COX proteins in both nonneoplastic and SCC-affected tissues in horses is markedly different from that in other species. The reason for the potential benefit of COX-2 inhibitors in horses and other species is unknown. Further research needs to be performed to evaluate the efficacy of COX-2 inhibitors as cancer treatments in horses. Investigation of the mechanisms of tumor development in horses should be performed to increase understanding of this disease and ascertain how the mechanisms differ from those in other animals.
Elce
Yvonne A
YA
Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606, USA.
Orsini
James A
JA
Blikslager
Anthony T
AT
D000818:Animals; D015153:Blotting, Western / Q000662:veterinary; D002294:Carcinoma, Squamous Cell / Q000201:enzymology / Q000662:veterinary*; D051545:Cyclooxygenase 1 / Q000096:biosynthesis*; D051546:Cyclooxygenase 2 / Q000096:biosynthesis*; D005260:Female; D006734:Horse Diseases / Q000201:enzymology*; D006736:Horses; D008297:Male; D009369:Neoplasms / Q000201:enzymology / Q000662:veterinary*
D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2