Establishment and characterization of six canine hepatocellular carcinoma cell lines (Transcriptional changes induced by drug treatment with toceranib or sorafenib)

Hepatocellular carcinoma (HCC) is the most common malignant liver tumor in dogs. Although surgical resection is a major treatment option for canine HCC, there are no distinct strategies for unresectable tumor subtypes or adjuvant chemotherapy for tumors with positive margins. We aimed to establish and characterize novel HCC cell lines from canine patients. The cellular morphology, general growth features and tumorigenicity of the established cell lines were evaluated. We also examined the sensitivity of the cell lines to multi-target tyrosine kinase inhibitors (TKIs). Toceranib, a veterinary TKI that targets vascular endothelial growth factor (VEGFR)/platelet-derived growth factor receptor (PDGFR)/c-kit, effectively inhibited the mitogen-activated protein kinase pathway and induced apoptosis. The established canine HCC cell lines showed greater sensitivity to toceranib than to sorafenib, a first-line treatment for human HCC targeting RAF/VEGFR/PDGFR. Sorafenib showed improved anti-tumor effects when co-treated with SCH772984, an extracellular signal-regulated kinase inhibitor. Our study suggests new therapeutic strategies for canine HCC, and these cell lines are valuable research materials for understanding HCC tumor biology in both humans and dogs. Overall design: We established canine HCC cell lines from hepatic tumors of six canine patients.To investigate the transcriptional changes induced by drug treatment in the cell lines, the cells were treated with toceranib (15µM) or sorefenib (30µM) for 24hrs. The cells treated with vehicle (sorafenib-DMSO, toceranib-DPBS) were used as control. Gene Ontology Biological Processes (GO-BP) enrichment analysis was performed using data obtained from RNA-seq of 4 different cell lines.