ANTIPROLIFERATIVE EFFECTS OF OXYTOCIN AND DESMOPRESSIN ON CANINE MAMMARY CANCER CELLS

BENAVENTE, M; BIANCHHI, C.; IMPERIALE, F.; ABA, M.

Mar del Plata

Congreso; XLVIII Reunión anual de la Asociación Argentina de Farmacología Experimental; 2016

Neoplasms of the mammary gland represent the mostfrequent tumor type in the female dog, and according to the histologic criteria,approximately 50% are malignant. In the most aggressive cases of mammarycancer, surgery is not enough to warrant a favorable outcome, and adjuvanttherapies are needed to improve the patient?s overall survival. Several invitro studies performed on murine and human cancer cells have suggestedthat some peptide hormones can modúlate tumor growth. However, little is knownabout its effects on canine cancer. The aim of the present study was toevaluate the effects of Oxytocin (OT) and Desmopressin (DDAVP) on proliferationof the canine mammary cancer cell line CMT-U27. The cells were grown in 96-wellplates, at two densities (4x103 and 8x103 cells/well) in 200 μl of RPMI-1640 supplemented with 10% Fetal BovineSerum. After overnight culture, the medium was removed and replaced with médiumcontaining OT or DDAVP at five concentrations: 10, 50, 100, 500 and 1000 nM, ormedium without drugs (controls). After 72 h of incubation, cell viability wasdetermined using the MTT colorimetric dye reduction method. With 4x103cells/well, OT at 1000 nM resulted in a 25% of inhibition of cellviability(p<0.01).Surprisingly, OT 50 nM resulted in a higher inhibitoryeffect (18%) than 500 nM (9%). At 8x103 cells/well, OT showed a significantantiproliferative effect (almost 25%) with the highest concentration(p<0.05). Desmopressin at 1000 nM and 4x103 cells/well reduced cell growthby 22% (p<0.05). At 50, 100, 500 nM the inhibitory effect was lower. With8x103cells/well, DDAVP at 100, 500 and 1000 nM exhibited a mildantiproliferative effect  (p>0.05). Inconclusion, OT and DDAVP can inhibit proliferation of CMT-U27 cells, by almost20% at the highest concentrations.Further studies are required to evaluate its potentialas antitumor agents, alone or combined with conventional cytotoxic drugs, for thetreatment of dogs with advanced mammary cancer.