Blocking of The Prostaglandin E2 Receptor as a Therapeutic Strategy for Treatment of Breast Cancer: Promising Findings in a Mouse Model

OBJECTIVE: The study aimed to investigate the anticancer effect of E-prostanoid receptor 1 (EP1) antagonist, SC19220, alone or in combination with the COX-2 inhibitor Celecoxob(CXB)(®) in mice bearing solid Ehrlich carcinoma (SEC). METHODS: The tumors were induced in 40 female mice, which were divided randomly into four equal groups (n= 10 in each group): Tumor control, CXB, EP1 antagonist, and co-treatment. CXB (10mg/kg) and EP1 antagonist (2mg/kg) were given intraperitoneally every three days, six times in total, then tissue was extracted and prepared for histopathology and measurement of weight, PGE2, and gene expression of EP1 and β 1 integrin. RESULTS: Both inhibitors, alone or in combination, showed a significant (p<0.001) antitumorigenic effect by decreasing, significantly (p<0.001), each of the tumor weights, tumor volumes, PGE2 levels, EP1 and β1-integrin gene expression along with increasing, significantly (p<0.001), the P53 tumor suppressor protein. The survival rate was improved from 80% in the control group to reach 100% in the treated groups. The co-treatment by CXB and EP1 antagonist showed a marked decrease in tumor weights and volumes as compared with the single treatment. In parallel, the histopathological findings showed enhanced apoptosis and diminished necrosis in the co-treated group. CONCLUSION: EP1 antagonist proved an antitumorigenic effect alone or combined with CXB and could play a new therapeutic strategy against breast cancer.