Carboplatin effect on canine benign mixed tumour-derived cells cultured under three-dimension system: apoptosis, cell viability and mitochondrial dysfunction

Canine mammary carcinomas represent an important pathology in small animal clinic, and benign mixed type carcinomas (MC-BMT) are one of the most diagnosed worldwide. The use of chemotherapeutic carboplatin has been one of the new protocols for the treatment of BMT. In this respect, three-dimensional cell culture (3D) represents an alternative in the evaluation of drugs by simulating what occurs in vivo. The present study aimed to verify the effect of carboplatin on 3D culture of cells derived from TMB, in addition to possible changes in cell viability, ballpoint size, apoptosis and Bcl-2/Bax ratio. For this, tumours samples were collected during mastectomy surgery procedure in private veterinary clinics, which were submitted to in vitro culture and part to histopathological analysis. After 28 days of 3D culture, spheroids were documented in both groups (treated and control) and sizes and morphology were compared. The carboplatin interfered in the cell viability by affecting their division and promoting apoptotic events. In the treated group, a higher transcription of Bax and caspase 3 was observed, in addition to low levels of caspases 2, 8 and 9, which was not observed in the control group. We thus suggest that mitochondrial dysfunction plays a critical role in cancer progression and that targeting mitochondrial alterations and mitochondrial retrograde signalling might be a promising strategy for the development of selective anticancer therapy. Thus, it was possible to demonstrate that the results achieved may contribute to the establishment of a new chemotherapy therapy in female dogs with MC-BMT.