Establishment and Characterization of Canine Mammary Gland Carcinoma Cell Lines with Vasculogenic Mimicry Ability in vitro and in vivo

Mammary neoplasm affects a population of intact and elderly female dogs and 50% are malignant. In order to study this disease, cell culture is as a promising preclinical model, creating the opportunity to deposit cell lines at a cell bank, allowing a great reproducibility of the assays and making the validation of the results more reliable. Another important aspect is the possibility to establish models for better understanding tumour characteristics, such as vasculogenic mimicry. Due the importance of cancer cell lines in preclinical models, this study aimed to establish and characterize primary cell lines from canine mammary gland tumours according to immunophenotype and tumorigenicity, and with its ability to form vasculogenic mimicry-like structures in vitro and in vivo. Cell cultures were evaluated for morphology, phenotype, vasculogenic mimicry and tumorigenicity abilities. We collected 17 primary mammary carcinoma and 3 metastasis and had a satisfactory result in 10 of them. All cell lines presented spindle shape or polygonal morphology and expressed concomitant pan-cytokeratin and cytokeratin 8/18. Four cell lines had vasculogenic mimicry ability in vitro and two of them showed in vivo tumorigenic potential and forming VM in the xenotransplant tumour. Cell characterization of those lines will help to create a database for more knowledge of mammary carcinomas in dogs, including studies of tumour behaviour and new therapeutic targets.