PhD Scientific Days 2025

Poster Session II. - G: Pharmaceutical Sciences and Health Technologies

Analyzing the Effect of Orally Administered Tyrosine Kinase Inhibitors in Different Leukocyte Populations

Name of the presenter

Markó Dorottya

Institute/workplace of the presenter

Department of Physiology, Semmelweis University

Authors

Dorottya Markó¹, Attila Mócsai¹, Krisztina Futosi¹, Dorottya Deli¹

1: Department of Physiology, Semmelweis University

Text of the abstract

Introduction: Tyrosine kinases play a critical role in regulating the signal transduction pathways in immune cells and serve as significant therapeutic targets in the treatment of various oncological, hematological, and inflammatory diseases.

Methods: Our research group previously developed a novel in vivo assay using flow cytometry to assess the effects of orally administered tyrosine kinase inhibitors on basal tyrosine phosphorylation in circulating mouse neutrophils. This method overcomes the limitations of in vitro analyses, such as predicting in vivo drug effects, permeability, and overall efficacy, by providing a more reliable assessment through in vivo testing. A major advantage of this assay is its ability to quantitatively analyze leukocyte tyrosine phosphorylation from a single drop of blood, enabling longitudinal studies without the need to sacrifice mice.

Aims: Our current study extends the assay to simultaneously analyze the effects of oral tyrosine kinase inhibitors across multiple leukocyte populations and to compare the relative sensitivities of these cell types to the inhibitors.

Results: Our results showed a near-complete inhibition of leukocyte tyrosine phosphorylation following administration of 50 mg/kg dasatinib at 2 hours post treatment. The inhibition was most pronounced in T cells, which showed high sensitivity to the inhibitor, while B cells showed the lowest sensitivity. Dose-response analyses revealed that T cells showed almost complete inhibition even at 5 mg/kg dasatinib, whereas B cells required 50 mg/kg dasatinib to achieve approximately 80% inhibition. Time-kinetic analysis further revealed that T cells exhibited a robust and prolonged inhibitory response, whereas B cells showed a weaker and more transient inhibition. Other leukocyte populations displayed intermediate levels of sensitivity.

Conclusion: This novel method provides an effective tool for comparative analysis of basal tyrosine phosphorylation across different leukocyte populations and for evaluating the dose-dependent and temporal effects of tyrosine kinase inhibitors in vivo.

Funding: Hungarian National Research Development and Innovation (KKP-129954 and TKP2021-EGA-24 to A.M.) and Semmelweis University’s Scientific and Innovation Fund (STIA-2021 to A.M.)