ABL Genomic Editing Sufficiently Abolishes Oncogenesis of Human Chronic Myeloid Leukemia Cells In Vitro and In Vivo

Abstract

Chronic myelogenous leukemia (CML) is the most common type of leukemia in adults, and more than 90% of CML patients harbor the abnormal Philadelphia chromosome (Ph) that encodes the BCR-ABL oncoprotein. Although the ABL kinase inhibitor (imatinib) has proven to be very effective in achieving high remission rates and improving prognosis, up to 33% of CML patients still cannot achieve an optimal response. Here, we used CRISPR/Cas9 to specifically target the BCR-ABL junction region in K562 cells, resulting in the inhibition of cancer cell growth and oncogenesis. Due to the variety of BCR-ABL junctions in CML patients, we utilized gene editing of the human ABL gene for clinical applications. Using the ABL gene-edited virus in K562 cells, we detected 41.2% indels in ABL sgRNA_2-infected cells. The ABL-edited cells reveled significant suppression of BCR-ABL protein expression and downstream signals, inhibiting cell growth and increasing cell apoptosis. Next, we introduced the ABL gene-edited virus into a systemic K562 leukemia xenograft mouse model, and bioluminescence imaging of the mice showed a significant reduction in the leukemia cell population in ABL-targeted mice, compared to the scramble sgRNA virus-injected mice. In CML cells from clinical samples, infection with the ABL gene-edited virus resulted in more than 30.9% indels and significant cancer cell death. Notably, no off-target effects or bone marrow cell suppression was found using the ABL gene-edited virus, ensuring both user safety and treatment efficacy. This study demonstrated the critical role of the ABL gene in maintaining CML cell survival and tumorigenicity in vitro and in vivo. ABL gene editing-based therapy might provide a potential strategy for imatinib-insensitive or resistant CML patients.

<em>Agaricus blazei</em> extract (FA‑2‑b‑&beta;) induces apoptosis in chronic myeloid leukemia cells

“…5A and B). Thus, FA-2-b-β induced both cell cycle arrest and apoptosis in K562 cells and primary CML BM cells, demonstrating similar findings to those that occur in the patients undergoing chemotherapy (27).…”

Platelet-Derived Growth Factor Receptor-α Subunit Targeting Suppresses Metastasis in Advanced Thyroid Cancer In Vitro and In Vivo

“…Among these potential tyrosine kinase inhibitors (TKIs), imatinib is the most specific to PDGFR kinases, with half-maximal inhibitory concentrations (IC50s) of 71 nM against PDGFRA and 607 nM against PDGFRB kinase activity in lung cells ( Medarametla et al ., 2014 ). Imatinib is a common chemotherapeutic used to treat Ph-positive CML and ALL, certain types of gastrointestinal stromal tumors, systemic mastocytosis and myelodysplastic syndrome ( Chen et al ., 2020 ). Here, to investigate whether a PDGFRA inhibitor could potentially be used as an advanced thyroid cancer therapy, we tested the anticancer effects of imatinib on SW579 cells.…”

“…5G ). In our previous study, we established a bioluminescence-based live cell NIADS to evaluate the quantitative and kinetic analyses of apoptotic cell death ( Hsu et al ., 2018 ; Chen et al ., 2019 ; Lin et al ., 2019 ; Chen et al ., 2020 ). Using this assay, we determined apoptotic events by simply measuring the bioluminescence activities of live cells.…”

Future Approaches for Treating Chronic Myeloid Leukemia: CRISPR Therapy

“…Recently, new work focusing on the disruption of BCR/ABL1 by genome-editing nucleases as a therapeutic strategy in CML has revealed the therapeutic potential of the CRISPR system. In 2020, Chia-Hwa Lee et al, using a CRISPR/Cas9 lentiviral vector to disrupt ABL1 in the human CML K562 cell line, demonstrated a reduced proliferation rate as a consequence of BCR/ABL1 disruption [ 103 ]. Ex vivo transduction of peripheral blood mononuclear cells from CML patients was performed to evaluate the therapeutic potential of this viral system in the clinical milieu.…”