In vitro and in vivo effects of toceranib phosphate on canine osteosarcoma cell lines and xenograft orthotopic models

Abstract

Canine osteosarcoma (OSA) is the most common primary malignant bone tumour in dogs, and it has a high metastatic rate and poor prognosis. Toceranib phosphate (TOC; Palladia, Zoetis) is a veterinary tyrosine kinase inhibitor that selectively inhibits VEGFR‐2, PDGFRs and c‐Kit, but its efficacy is not yet fully understood in the treatment of canine OSA. Here, we evaluated the functional effects of TOC on six OSA cell lines by transwell, wound healing and colony formation assays. Subsequently, two cell lines (Wall and Penny) were selected and were inoculated in mice by intrafemoral injection to develop an orthotopic xenograft model of canine OSA. For each cell line, 30 mice were xenografted; half of them were used as controls, and the other half were treated with TOC at 40 mg/kg body weight for 20 days. TOC inhibited cell growth of all cell lines, but reduced invasion and migration was only observed in Penny and Wall cell lines. In mice engrafted with Penny cells and subjected to TOC treatment, decreased tumour growth was observed, and PDGFRs and c‐Kit mRNA were downregulated. Immunohistochemical analyses demonstrated a significant reduction of Ki67 staining in treated mice when compared to controls. The results obtained here demonstrate that TOC is able to slightly inhibit cell growth in vitro, while its effect is evident only in a Penny cell xenograft model, in which TOC significantly reduced tumour size and the Ki67 index without modifying apoptosis markers.

Genomic and Transcriptomic Characterization of Canine Osteosarcoma Cell Lines: A Valuable Resource in Translational Medicine

“…Specifically, two commercial and six primary cOSA cell lines established and validated in our laboratory were analyzed. The assorted cell lines were previously used in several studies to investigate cOSA pathogenetic mechanisms and response to therapies (11,12,14,(36)(37)(38). So far, only the D17 cell line has been characterized at the genomic level by Das et al in 2019 (13).…”

An Update on Molecular Pathways Regulating Vasculogenic Mimicry in Human Osteosarcoma and Their Role in Canine Oncology

“…Furthermore, no significant correlation was observed between the expression of these molecules and survival or histological grading in canine OSA ( 105 ). Despite this, the significant relation of this axis with malignant features of canine OSA has been observed both in vivo and in vitro ( 111 ). In fact, treating OSA cells with Toracenib, a potent inhibitor of PDGFRs, has been shown to induce a decrease in cell growth, migration, motility, and colony formation, as well as a significant blunting of tumor growth and proliferation index in an orthotopic xenograft model ( 111 ).…”

“…Despite this, the significant relation of this axis with malignant features of canine OSA has been observed both in vivo and in vitro ( 111 ). In fact, treating OSA cells with Toracenib, a potent inhibitor of PDGFRs, has been shown to induce a decrease in cell growth, migration, motility, and colony formation, as well as a significant blunting of tumor growth and proliferation index in an orthotopic xenograft model ( 111 ). These findings suggest that PDGF/PDGFR axis can represent a target therapy more than a diagnostic tool.…”

Editorial

“…Included in this issue are reviews aimed at understanding the clinical and pathological course of sarcomas by refining histologic classification and improving or standardizing histologic margin assessment of sarcomas . Original research manuscripts investigating the basic biology of sarcoma cells include studies evaluating the effects of toceranib phosphate in vitro and in vivo and a potential role for adrenergic receptor antagonists in moderating radiosensitivity . Yet another manuscript builds on previous data and identifies the interaction between RUNX2 and core‐binding factor beta as a potential target in osteosarcoma cells .…”