Recruiting TP53 to target chronic myeloid leukemia stem cells

Tyrosine Kinase Inhibitor Therapy Enhances Stem Cells Profile and May Contribute to Survival of Chronic Myeloid Leukemiastem Cells

Background/Objectives: Treatment with tyrosine kinase inhibitors (TKIs) in chronic myeloid leukemia (CML) has revolutionized disease management and has transformed CML from a life-threatening disease to a chronic condition for many patients. However, overcoming resistance, particularly related to leukemic stem cells (LSC) that can persist even when the bulk of the leukemic cells are eliminated, remains a significant challenge. Methods: K562 and KU812 cell lines were treated in vitro with the TKI Imatinib (IM). Gene expression, protein analysis, and metabolomic screening were conducted to investigate the ability of the drug to enhance stem cell (SC) features. Moreover, a gene ontology analysis was performed on different available datasets, to further consolidate our data. Results: 48 h of IM treatment can significantly increase the expression of genes related to SC self-renewal, particularly SOX2 and OCT 3/4. Interestingly, these modulations occur in cells that remain alive after drug treatment and that displayed features consistent with leukemia stem-like CML cells, suggesting that SC genes levels are crucial even in cell population survived upon TKI treatment. Moreover, after in silico analysis of available data, we observed an enrichment of SOX2/NANOG and OCT 3/4 signatures after TKI treatment, thus strengthening our results. Conclusions: Our results confirmed the relevance of LSC features after TKI treatment, highlighting the need for more effective and potentially curative strategies targeting LSCs to overcome resistance in CML.

Chronic myeloid leukemia stem cells: targeting therapeutic implications

Chronic myeloid leukemia (CML) is a clonal myeloproliferative neoplasm driven by BCR-ABL1 oncoprotein, which plays a pivotal role in CML pathology, diagnosis, and treatment as confirmed by the success of tyrosine kinase inhibitor (TKI) therapy. Despite advances in the development of more potent tyrosine kinase inhibitors, some mechanisms particularly in terms of CML leukemic stem cell (CML LSC) lead to intrinsic or acquired therapy resistance, relapse, and disease progression. In fact, the maintenance CML LSCs in patients who are resistance to TKI therapy indicates the role of CML LSCs in resistance to therapy through survival mechanisms that are not completely dependent on BCR-ABL activity. Targeting therapeutic approaches aim to eradicate CML LSCs through characterization and targeting genetic alteration and molecular pathways involving in CML LSC survival in a favorable leukemic microenvironment and resistance to apoptosis, with the hope of providing a functional cure. In other words, it is possible to develop the combination therapy of TKs with drugs targeting genes or molecules more specifically, which is required for survival mechanisms of CML LSCs, while sparing normal HSCs for clinical benefits along with TKIs.

Targeting Abnormal Hematopoietic Stem Cells in Chronic Myeloid Leukemia and Philadelphia Chromosome-Negative Classical Myeloproliferative Neoplasms

Myeloproliferative neoplasms (MPNs) are unique hematopoietic stem cell disorders sharing mutations that constitutively activate the signal-transduction pathways involved in haematopoiesis. They are characterized by stem cell-derived clonal myeloproliferation. The key MPNs comprise chronic myeloid leukemia (CML), polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). CML is defined by the presence of the Philadelphia (Ph) chromosome and BCR-ABL1 fusion gene. Despite effective cytoreductive agents and targeted therapy, complete CML/MPN stem cell eradication is rarely achieved. In this review article, we discuss the novel agents and combination therapy that can potentially abnormal hematopoietic stem cells in CML and MPNs and the CML/MPN stem cell-sustaining bone marrow microenvironment.