Prostaglandin E2 concentrations in naturally occurring canine cancer

The purpose of this study was to determine the PGE2 concentration in naturally-occurring cancer in pet dogs and in canine cancer cell lines in order to identify specific types of canine cancer with high PGE2 production which could serve as preclinical models to evaluate anticancer strategies targeting PGE2. PGE2 concentrations were measured by enzyme immunoassay in canine melanoma, soft tissue sarcoma, transitional cell carcinoma, osteosarcoma, and prostatic carcinoma cell lines; in 80 canine tumor tissue samples including oral melanoma (MEL), oral squamous cell carcinoma (SCC), transitional cell carcinoma of the urinary bladder (TCC), lymphoma (LSA), mammary carcinoma (MCA), osteosarcoma (OSA), prostatic carcinoma (PCA); and in corresponding normal organ tissues. High concentrations of PGE(2)(range 400-3300 pg/10(4)cells) were present in cell culture medium from the transitional cell carcinoma, prostatic carcinoma, and osteosarcoma cell lines. PGE2 concentrations in tumor tissues were elevated (tumor PGE2 concentration>mean+2X sd PGE(2)concentration of normal organ tissue) in 21/22 TCC, 5/6 PCA, 7/10 SCC, 5/10 MEL, 3/8 MCA, 4/15 OSA, and 0/9 LSA. Results of this study will help guide future investigations of anticancer therapies that target cyclooxygenase and PGE2.