Role of Meloxicam as a selective inhibitor of COX-2 in the inhibition of Ehrlich solid tumor growth

Abstract

High levels of cyclooxygenase (COX) enzymes and its metabolites, especially prostaglandin E2 (PGE2) are generated in inflammatory conditions and, eventually, can contribute to neoplasms growth, justifying, in certain malignancies. COX occurs in two major isoforms, physiologically as isoform COX-1 and during inflammation as COX-2. In certain neoplasms, benefits are reported with the use of the selective COX-2 inhibitor drug, meloxicam. This study aimed to evaluate the effect of meloxicam on the development of solid Ehrlich tumor. Fourteen male Swiss mice, 30-45 days old, 35-45 g of weight, were inoculated with 10 7 of the tumor cells, and divided in two groups according to the treatment: Phys) 0.1 mL intraperitoneal injection (IP) of sterile 0.9% saline solution, and Mel) treated with meloxicam, 2 mg/kg, 0.1 mL, IP, both once a day. After 21 days, all the animals were euthanized and the tumor removed, weighed and prepared for histomorphometric and immunohistochemical evaluation for COX-2. Mel group presented significantly reduction of the tumor weight and COX-2 production, as well as an increase in stromal component, but did not interfere in tumor growth, in comparison to Phys group. From these results it was concluded that meloxicam did not restrain tumor growth in this experimental model. Reduction in tumor weight alone cannot be taken as a reliable criterion for evaluation of tumor progression.