In vitro drug sensitivity in canine lymphoma

Introduction: Due to the high heterogeneity of canine lymphoma, the aim of the present study was to test in vitro the chemosensitivity of canine high-grade primary lymphoma cells to various cytostatic drugs commonly used to treat dogs: 4-HO-cyclophosphamide, doxorubicin, dexamethasone, prednisolone, vincristine, etoposide, chlorambucil, lomustine, and cytosine arabinoside. Material and Methods: To determine the cell viability and drug ability to induce apoptosis two different tests were used: an MTT assay and annexin V/propidium iodide staining. Results: Both in vitro tests were found to be useful tools. Significant differences in the sensitivity, depending on the drug type, between B-, T- and mixed/null-type lymphoma cells were found for the majority of the tested drugs. B-type cells were the most sensitive in vitro, whereas T-type cells seemed to be the most resistant. Doxorubicin, chlorambucil, etoposide, and vincristine most strongly reduced the cell viability and induced apoptosis. Conclusion: In vitro assays, such as the MTT test and especially the annexin V/PI assay, may be useful tools for predicting a response to the treatment of high-grade lymphoma in dogs or improving the treatment outcomes in individual animals.