Investigation of the Therapeutic Effects of Removing STAT5A with CRISPR/Cas9 Genome Editing Technology in Chronic Myeloid Leukemia Cells Resistant to Tyrosine Kinase Inhibitors
Project no. 75591 · Status: Kapanmış · 2022
Summary
<p>Chronic myeloid leukemia (CML) is a chronic myeloproliferative neoplasm characterized by the oncoprotein BCR-ABL1 (Breakpoint-cluster region/Abelson kinase), a fusion protein with constitutive tyrosine kinase activity. Tyrosine kinases are important mediators of this signal transduction process that leads to cell proliferation, differentiation, cell migration, metabolism, and programmed cell death. Tyrosine kinase signaling pathways normally prevent dysregulated proliferation or contribute to sensitivity to apoptotic stimuli. The role of tyrosine kinases in the molecular pathogenesis of cancer is immense, and recently, with kinases in vogue as potential anticancer drug targets, Imatinib and the second-generation tyrosine kinase inhibitors (TKIs) nilotinib and dasatinib have statistically significantly improved prognosis and life expectancy. In patients with chronic myeloid leukemia, however, resistance to TKIs remains a significant clinical challenge. Although ponatinib, a third-generation TKI, improves outcomes in patients with BCR-ABL-dependent resistance mechanisms, a proportion of patients develop BCR-ABL independent resistance and fail ponatinib treatment. In chronic myeloid leukemia, signal transducer and transcription activator 5a – STAT5A is a crucial downstream effector of tyrosine kinase oncogenes (TKOs) such as BCR-ABL and, based on transcriptomic study, it suppresses the expression of STAT5A and runt-related transcription factor 3 (RUNX3). Its increase may also cause resistance to Tyrosine Kinase Inhibitors. STAT5A has also been shown to increase the resistance of CML cells to tyrosine kinase inhibitors (TKIs) such as imatinib the mesylate. Inactivation of a gene encoding an enzyme important in chemoresistance of a particular cancer using CRISPR/CAS9 is a potential treatment that could be given before or in conjunction with chemotherapy. In this study, the genome editing technology CRISPR of Signal Transducer and Transcription Activator 5A – STAT5A was used in Chronic myeloid leukemia cell model K562 and its form K562/Ima-Res, which was resistant to 1.2 µM Imatinib, and K562/Pon-Res, which was resistant to 3 nM Ponatinib. It was aimed to determine the effects on cytotoxic, apoptotic, cell cycle arrest on leukemic cells and the expression changes at the mRNA level of selected genes in key carcinogenetic pathways after the removal of CRISPR/Cas9. </p>