PHOSPHOPROTEOM ANALYSIS OF CHRONIC MYELOID LEUKEMIA CELLS USING PROTEIN ARRAYS

Sborník

Backround. There are probably a number of mechanisms of resistance to tyrosine kinase inhibitors. It has been suggested that in many cases over time from chronic myeloid leukemia (CML) diagnosis, the disease may become partially or totally BCR-ABL independent, driven by other proteins, especially kinases. List of those proteins is probably still incomplete and is increasing rapidly. Knowledge of the other players in CML pathogenesis is of high importance as it might improve both CML patients monitoring and therapy. Aims. In our current study, we aim to select proteins differentially activated in CML patients with different responses to kinase inhibitor therapies (imatinib, nilotinib, dasatinib). These proteins might serve as novel biomarkers and therapy targets. We look at the changes in CML cell lines and primary patients´ leukocytes treated with tyrosine kinase inhibitors in vitro. As many proteins are activated/deactivated by phosphorylation at different sites, we aim to study phoshoproteom of CML cells. Methods. We have applied commercially available protein arrays to see phosphorylation profiles. Antibody array analyses were optimized and data for selected proteins were checked by Western blot analyses.4.ResultsPreliminary data showed differences in activated pathways in samples of patients with different response to therapy and CML aggressiveness. In our study, we found differences in phosphorylation status of different kinases including Src family (Src, Yes) and others (BTK, ZAP-70). Interestingly, we also found differences in proteins which regulate cellular kinases (CSK) or interact with them (GRB2, GRAP) and influence their effects. Differences in expression and/or activation of such regulators might explain different CML aggressiveness in patients with comparable levels of BCR-ABL. Differences were found upon treating CML cell lines and primary patients´ leukocytes with tyrosine kinase in vitro.Summary and conclusions. Protein antibody arrays are novel promising tool to provide complex insights into disease pathogenesis. Complex coverage of the proteome by todays´ available protein arrays allow to reveal important pathways in disease pathogenesis and to find novel markers and targets for therapy.Grant support: NT/12392-4 IGA MZ-CR

Haematologica, 2012; 97(s1):  381