In vitro drug sensitivity in canine lymphoma

Abstract

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.

Pharmacokinetics of a cytosine arabinoside subcutaneous protocol in dogs with meningoencephalomyelitis of unknown aetiology

“…There are few studies which have investigated pharmacodynamic end points of CA in dogs, both of which evaluated canine lymphoma and leukaemia cell lines (Pawlak et al., 2014; 2016). While Pawlak et al., (2016) found that CA demonstrated moderate to high efficacy as determined by the percentage of apoptotic/dead neoplastic cells following incubation with CA at a concentration of 1 µg/ml, neoplastic cells can exhibit altered chemosensitivity and pharmacodynamic properties when compared to other cell populations. Thus, these results may not accurately predict CA activity against the non‐neoplastic inflammatory cells that mediate MUE.…”

“…It is S‐phase specific and causes competitive inhibition of DNA polymerase in mitotically active cells, thus preventing DNA replication, halting the cell cycle and precipitating apoptosis (Gmeiner et al., 2003; Scott‐Moncrief et al., 1991; Withrow et al., 2012). It has therefore been used for the treatment of multiple disease processes involving pathologic cell replication, including lymphoma (involving the bone marrow or central nervous system and in cases of relapse), leukaemia and optic neuritis of non‐infectious origin (Gillem et al., 2015; Marconato et al., 2008; LaRue et al., 2018; Pawlak et al., 2014, 2016; Bedos et al., 2020; Alvarez et al., 2006). As MUE is highly suspected to be due to a robust T‐cell autoimmune response, CA has been utilized as a treatment option for meningoencephalomyelitis of unknown aetiology (MUE) with the goal of inhibiting the pathologic lymphocyte proliferation associated with this autoimmune disease (Vitale et al., 2019).…”

Predicting likelihood of in vivo chemotherapy response in canine lymphoma using ex vivo drug sensitivity and immunophenotyping data in a machine learning model

“…However, the identification of relevant features is a challenge in any biological model. Direct measurements of treatment response in primary tumour samples are almost certainly relevant to treatment response in patients 18 . However, ex vivo assessments of chemosensitivity may not fully capture the behaviour of drugs or cells in vivo, which may render these measures insufficient to fully predict individual treatment responses alone.…”

“…Cell‐based ex vivo drug sensitivity assays have been widely studied as a precision medicine tool to recapitulate the tumour microenvironment in vitro and predict in vivo responses in human lymphoproliferative disorders 13‐17 . For canine lymphoma, Pawlak et al reported an in vitro chemosensitivity assay that measures the cytotoxicity of various anticancer reagents in high‐grade primary lymphoma cells 18 . This previous work showed that drug sensitivity varies among individual patients and that a direct measurement of drug response in primary cancer cells is a potential predictor of actual response in the body.…”

“…However, parameters derived from the outcome of a drug sensitivity assay alone can be insufficient when predicting in vivo response. Adding other phenotypic information such as the immunophenotype of a patient's cancer cells as determined by flow cytometry may enhance the predictive value of ex vivo drug sensitivity testing 18,19 …”