o:1616 Isolation and Characterization of Novel Canine Osteosarcoma Cell Lines from Chemotherapy-Naïve Patients en The present study aimed to establish novel canine osteosarcoma cell lines (COS3600, COS3600B, COS4074) and characterize the recently described COS4288 cells. The established D-17 cell line served as a reference. Analyzed cell lines differed notably in their biological characteristics. Calculated doubling times were between 22 h for COS3600B and 426 h for COS4074 cells. COS3600B and COS4288 cells produced visible colonies after anchorage-independent growth in soft agar. COS4288 cells were identified as cells with the highest migratory capacity. All cells displayed the ability to invade through an artificial basement membrane matrix. Immunohistochemical analyses revealed the mesenchymal origin of all COS cell lines as well as positive staining for the osteosarcoma-relevant proteins alkaline phosphatase and karyopherin α2. Expression of p53 was confirmed in all tested cell lines. Gene expression analyses of selected genes linked to cellular immune checkpoints (CD270, CD274, CD276), kinase activity (MET, ERBB2), and metastatic potential (MMP-2, MMP-9) as well as selected long non-coding RNA (MALAT1) and microRNAs (miR-9, miR-34a, miR-93) are provided. All tested cell lines were able to grow as multicellular spheroids. In all spheroids except COS4288, calcium deposition was detected by von Kossa staining. We believe that these new cell lines serve as useful biological models for future studies. P53 Mutations; C-Met; Receptor Expression; Establishment; Tumor; Overexpression; Involvement 1552099 10.3390/cells12071026 2023-05-10T15:01:26.453Z 44 yes 46 Natascha Leitner University of Veterinary Medicine Vienna Reinhard Ertl University of Veterinary Medicine Vienna person 0000-0001-7485-3661 Simone Gabner University of Veterinary Medicine Vienna person 0000-0001-8853-5939 Andrea Fuchs-Baumgartinger University of Veterinary Medicine Vienna person Ingrid Walter University of Veterinary Medicine Vienna person 0000-0002-5038-188X Juraj Hlavaty University of Veterinary Medicine Vienna person 0000-0003-3050-5176 application/pdf 4068155 https://phaidra.vetmeduni.ac.at/o:1616 no yes 16 70 1552253 Vaccines 22 12 7 MDPI 2023