Oxibendazole induces cell cycle arrest and apoptosis in canine large-cell alimentary lymphoma cells

Canine large-cell alimentary lymphoma (LCAL) responds poorly to chemotherapy and carries a poor prognosis. We investigated the antitumor effects of oxibendazole (OBZ), a benzimidazole anthelmintic identified by drug screening, in three canine LCAL cell lines. OBZ reduced cell viability in a dose-dependent manner, with half-maximal inhibitory concentration values of 0.08-0.16 μM. Cell cycle analysis showed increased G2/M and sub-G1 fractions, whereas an annexin V/propidium iodide assay demonstrated increased early and late apoptotic cells. Western blotting demonstrated caspase-3 cleavage following OBZ treatment. These findings indicate that OBZ exerts antitumor effects against canine LCAL cells by inducing G2/M cell cycle arrest and caspase-dependent apoptosis and suggest that OBZ may be a candidate for drug repurposing in canine LCAL.