In vitro chemosensitivity testing of the feline large granular lymphocyte cell line (S87)

Background Feline large granular lymphocyte (LGL) lymphoma is an aggressive neoplasia characterised by short survival and poor response to chemotherapy. Objectives In this study, the effect of different chemotherapeutic agents on the growth kinetics of the feline cell line S87, a non‐MHC‐restricted feline LGL cell line, was investigated. Where possible, IC50 (inhibitory concentration 50) values were determined. The IC50 values of the cell line as lymphoma models can provide clues to the situation in vivo and serve as a basis for studying resistance mechanisms. Methods Cells were incubated with various concentrations of vincristine, doxorubicin, 4‐hydroperoxycyclophosphamide, prednisolone, methotrexate and L‐asparaginase for 24 and 48 h, respectively. Results The IC50 values could be determined as 14.57 (7.49–28.32) μg/mL at 24 h incubation and 5.72 (4.05–8.07) μg/mL at 48 h incubation for doxorubicin and 9.12 (7.72–10.76) μg/mL at 24 h incubation and 4.53 (3.74–5.47) μg/mL at 48 h incubation for 4‐hydroperpoxycyclophosphamide. Treatment with vincristine and methotrexate resulted in relatively high cell resistance whereas L‐asparaginase and prednisolone treatment led to a reduction in cell number compared to control while cell viability was not affected (cytostatic effect). Conclusion Overall, the feline LGL cell line S87 proves to be relatively sensitive to doxorubicin and 4‐hydroperoxycyclophosphamide and relatively resistant to treatment with vincristine, prednisolone, methotrexate and L‐asparaginase. The results of this study can be used for further investigations on resistance mechanisms in feline LGL lymphoma. Doxorubicin and cyclophosphamide can be interpreted as promising candidates for the therapy of feline LGL lymphomas. The aim of the study was to evaluate the reaction of a feline large granular lymphocyte (LGL) cell line on in vitro chemotherapy, as feline LGL lymphoma are commonly described to be very aggressive and to have a short median survival time even if treated with chemotherapy. This paper describes the effect of different common chemotherapeutic agents (vincristine, doxorubicin, 4‐hydroperoxycyclophosphamide, methotrexate, L‐asparaginase and prednisolone) on the feline LGL cell line S87.