Molecular events associated with resistance to tyrosine kinase inhibitors in leukemia cells.

Chronic myeloid leukemia (CML) is a myeloproliferative stem cell disease characterized by the expression of BCR-ABL oncoprotein with constitutive tyrosine kinase activity. Although the development of tyrosine kinase inhibitors (TKI) such as imatinib dramatically improved the treatment of CML, a certain subset of patients develops resistance to TKI drugs. The most common cause of TKI resistance are point mutations in the BCR-ABL1 gene, followed by other mutation-independent mechanisms. Survival and proliferation of CML cells in the presence of TKI drugs are accompanied by adaptive changes in their metabolism. Drug resistance can be maintained by extrinsic signals, among which exosomes, small vesicles released by (drug-resistant) cells, have been shown to play an important role. The aim of this thesis was to characterize two CML cell lines sensitive and resistant to imatinib, as well as the exosomes derived from imatinib-resistant CML cells by proteomic approaches. Identification of metabolic vulnerabilities in drug-resistant cells enables their targeting by clinically available drugs, thus offering potential therapeutic targets for their selective elimination. Analysis of exosomes derived from imatinib-resistant cells can identify specific membrane surface proteins exploitable as clinically relevant..