Primitive, quiescent, Philadelphia-positive stem cells from patients with chronic myeloid leukemia are insensitive to STI571 in vitro

Blood ◽  
2002 ◽  
Vol 99 (1) ◽  
pp. 319-325 ◽  
Author(s):  
Susan M. Graham ◽  
Heather G. Jørgensen ◽  
Elaine Allan ◽  
Charlie Pearson ◽  
Michael J. Alcorn ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Stem Cells ◽  
Growth Factors ◽  
Chronic Myeloid Leukemia ◽  
Antiproliferative Activity ◽  
Myeloid Leukemia ◽  
Kinase Inhibitor ◽  
Chronic Phase ◽  
Quiescent State

In clinical trials, the tyrosine kinase inhibitor STI571 has proven highly effective in reducing leukemic cell burden in chronic myeloid leukemia (CML). The overall sensitivity of CML CD34+ progenitor cells to STI571 and the degree to which cell death was dependent on cell cycle status were determined. Stem cells (Lin−CD34+) from the peripheral blood of patients with CML in chronic phase and from granulocyte–colony-stimulating factor–mobilized healthy donors were labeled with carboxy-fluorescein diacetate succinimidyl diester dye to enable high-resolution tracking of cell division. Then they were cultured for 3 days with and without growth factors ± STI571. After culture, the cells were separated by fluorescence-activated cell sorting into populations of viable quiescent versus cycling cells for genotyping. For healthy controls, in the presence of growth factors, STI571 affected neither cell cycle kinetics nor recovery of viable cells. In the absence of growth factors, normal cells were unable to divide. For CML samples, in the presence or absence of growth factors, the response to STI571 was variable. In the most sensitive cases, STI571 killed almost all dividing cells; however, a significant population of viable CD34+ cells was recovered in the undivided peak and confirmed to be part of the leukemic clone. STI571 also appeared to exhibit antiproliferative activity on the quiescent population. These studies confirm that CML stem cells remain viable in a quiescent state even in the presence of growth factors and STI571. Despite dramatic short-term responses in vivo, such in vitro insensitivity to STI571, in combination with its demonstrated antiproliferative activity, could translate into disease relapse after prolonged therapy.

scholarly journals C/EBPβ is a critical mediator of IFN-α–induced exhaustion of chronic myeloid leukemia stem cells

2019 ◽  
Vol 3 (3) ◽  
pp. 476-488 ◽  
Author(s):  
Asumi Yokota ◽  
Hideyo Hirai ◽  
Ryuichi Sato ◽  
Hiroko Adachi ◽  
Fumiko Sato ◽  
...  
Keyword(s):  
Stem Cells ◽  
Chronic Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Chronic Phase ◽  
Interferon Α ◽  
Dependent Manner ◽  
Distal Enhancer ◽  
Induced Differentiation ◽  
Ifn Γ

Abstract Even in the era of ABL tyrosine kinase inhibitors, eradication of chronic myeloid leukemia (CML) stem cells is necessary for complete cure of the disease. Interferon-α (IFN-α) has long been used for the treatment of chronic-phase CML, but its mechanisms of action against CML stem cells remain unclear. We found that IFN-α upregulated CCAAT/enhancer binding protein β (C/EBPβ) in BCR-ABL–expressing mouse cells by activating STAT1 and STAT5, which were recruited to a newly identified 3′ distal enhancer of Cebpb that contains tandemly aligned IFN-γ–activated site elements. Suppression or deletion of the IFN-γ–activated site elements abrogated IFN-α–dependent upregulation of C/EBPβ. IFN-α induced differentiation and exhaustion of CML stem cells, both in vitro and in vivo, in a C/EBPβ-dependent manner. In addition, IFN-α upregulated C/EBPβ and induced exhaustion of lineage− CD34+ cells from CML patients. Collectively, these results clearly indicate that C/EBPβ is a critical mediator of IFN-α–induced differentiation and exhaustion of CML stem cells.

Chronic Myeloid Leukemia Stem Cells and Their Differentiated Progeny Display Divergent Drug Sensitivities to Imatinib Mesylate and Interferon-Alpha.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1996-1996 ◽  
Author(s):  
William Matsui ◽  
Greg R. Angstreich ◽  
Milada S. Vala ◽  
James P. Barber ◽  
Anita L. Hawkins ◽  
...  
Keyword(s):  
Stem Cells ◽  
Growth Factors ◽  
Chronic Myeloid Leukemia ◽  
Clinical Response ◽  
Interferon Alpha ◽  
Myeloid Leukemia ◽  
Terminal Differentiation ◽  
Gm Csf

Abstract Imatinib has largely replaced interferon-alpha (IFN) as front-line therapy in the treatment of chronic myeloid leukemia (CML) because of its favorable toxicity profile and superior initial response rate. However, recent laboratory data demonstrating that CML stem cells may have limited susceptibility to imatinib brings into question the potential durability of these responses. In contrast, responses to IFN often take place over months or years, but extensive long-term clinical data indicate that they are often long lasting. In order to determine if the differences in clinical response kinetics could be explained by the activity of imatinib and IFN against CML stem cells or their differentiated progeny, we examined the effects of each agent on distinct cellular subsets in vitro. CD34+ CML progenitors were isolated from 4 patients with newly diagnosed chronic phase CML and incubated with IFN (1000U/ml) or imatinib (10μM) for 96 hours followed by long-term liquid culture over 1-3 weeks to assay more primitive CML stem cells. The effects of each drug on CML progenitors was determined by calculating the number of CFU-GM positive for BCR-ABL by FISH and comparing these values to the bcr-abl+ CFU-GM formed by untreated control cells. Initially, the CML CFU-GM recovery immediately following 96 hours of drug treatment was 62.7 ± 8% and 9.7 ± 2% from IFN and imatinib-treated groups, respectively. After 3 weeks of long-term culture, CML CFU-GM recovery was 23.4 ± 2.6% following IFN treatment and 57.3 ± 22% after imatinib. Thus, imatinib was significantly more toxic to committed CML progenitors than primitive CML progenitors responsible for the maintenance of long-term liquid cultures (p = 0.04). Conversely, IFN had significantly greater activity against primitive CML progenitors than committed progenitors (p = 0.05). Although IFN has diverse biological properties, the mechanisms responsible for its antileukemic activity are unknown. Treatment of the human CML cell line KT-1 with IFN resulted in increased expression of the myeloid antigens CD33 and myeloperoxidase as well as the inhibition of clonogenic growth demonstrating that IFN induced terminal differentiation. Furthermore, several groups have shown that myeloid growth factors also induce differentiation of CML cells in vitro and clinically enhance the activity of IFN; accordingly, the addition of GM-CSF (200U/ml) augmented the differentiation of KT-1 cells. Moreover, myeloid growth factors were required for differentiation as neutralizing antibodies against GM-CSF and IL-3 inhibited the activity of IFN. The addition of GM-CSF to IFN produced similar effects on clinically derived CD34+ CML cells. Although imatinib is a potent inhibitor of committed CML progenitors, it is relatively ineffective against more primitive CML stem cells. In contrast, IFN appears to act primarily against CML stem cells by inducing terminal differentiation that is dependent on the activity of myeloid growth factors. Imatinib and IFN have divergent effects on CML progenitors at different stages of maturation that may correlate with clinical response kinetics and durability.

scholarly journals CD93 is expressed on chronic myeloid leukemia stem cells and identifies a quiescent population which persists after tyrosine kinase inhibitor therapy

Leukemia ◽  
2020 ◽  
Vol 34 (6) ◽  
pp. 1613-1625 ◽  
Author(s):  
Ross Kinstrie ◽  
Gillian A. Horne ◽  
Heather Morrison ◽  
David Irvine ◽  
Chinmay Munje ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Chronic Myeloid Leukemia ◽  
Tyrosine Kinase ◽  
Myeloid Leukemia ◽  
Kinase Inhibitor ◽  
Residual Disease ◽  
Important Indicator ◽  
Disease Persistence

AbstractThe introduction of BCR-ABL tyrosine kinase inhibitors has revolutionized the treatment of chronic myeloid leukemia (CML). A major clinical aim remains the identification and elimination of low-level disease persistence, termed “minimal residual disease”. The phenomenon of disease persistence suggests that despite targeted therapeutic approaches, BCR-ABL-independent mechanisms exist which sustain the survival of leukemic stem cells (LSCs). Although other markers of a primitive CML LSC population have been identified in the preclinical setting, only CD26 appears to offer clinical utility. Here we demonstrate consistent and selective expression of CD93 on a lin−CD34+CD38−CD90+ CML LSC population and show in vitro and in vivo data to suggest increased stem cell characteristics, as well as robust engraftment in patient-derived xenograft models in comparison with a CD93− CML stem/progenitor cell population, which fails to engraft. Through bulk and single-cell analyses of selected stem cell and cell survival-specific genes, we confirmed the quiescent character and demonstrate their persistence in a population of CML patient samples who demonstrate molecular relapse on TKI withdrawal. Taken together, our results identify that CD93 is consistently and selectively expressed on a lin−CD34+CD38−CD90+ CML LSC population with stem cell characteristics and may be an important indicator in determining poor TKI responders.

scholarly journals Alternative approaches to eradicating the malignant clone in chronic myeloid leukemia: tyrosine-kinase inhibitor combinations and beyond

Hematology ◽  
2013 ◽  
Vol 2013 (1) ◽  
pp. 189-200 ◽  
Author(s):  
Wesam Ahmed ◽  
Richard A. Van Etten
Keyword(s):  
Stem Cells ◽  
Clinical Trials ◽  
Chronic Myeloid Leukemia ◽  
Tyrosine Kinase ◽  
Cell Biology ◽  
Myeloid Leukemia ◽  
Kinase Inhibitor ◽  
Residual Disease ◽  
Chronic Phase

Abstract In patients with chronic myeloid leukemia (CML) in chronic phase who have achieved complete molecular remission on imatinib therapy, clinical trials from France and Australia have demonstrated that the majority experience prompt molecular relapse of their leukemia upon discontinuation of the drug, showing that long-term monotherapy with tyrosine kinase inhibitors is not curative in the majority of patients with CML. This has focused attention on strategies to eradicate residual disease in CML that is presumed to arise from malignant Ph+ stem cells, which should result in permanent cure and long-term leukemia-free survival. Here, we review the evidence that targeting CML stem cells will be of clinical benefit and discuss pharmacological and immunological approaches to accomplish this goal. Where possible, we link preclinical studies of CML stem cell biology to emerging results from clinical trials of agents that may target these cells.

scholarly journals Bosutinib is active in chronic phase chronic myeloid leukemia after imatinib and dasatinib and/or nilotinib therapy failure

Blood ◽  
2012 ◽  
Vol 119 (15) ◽  
pp. 3403-3412 ◽  
Author(s):  
H. Jean Khoury ◽  
Jorge E. Cortes ◽  
Hagop M. Kantarjian ◽  
Carlo Gambacorti-Passerini ◽  
Michele Baccarani ◽  
...  
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Adverse Events ◽  
Myeloid Leukemia ◽  
Kinase Inhibitor ◽  
Phase 1 ◽  
Chronic Phase ◽  
Progression Free Survival ◽  
Cytogenetic Response ◽  
Abl Tyrosine Kinase ◽  
Kaplan Meier

Bosutinib, a dual Src/Abl tyrosine kinase inhibitor (TKI), has shown potent activity against chronic myeloid leukemia (CML). This phase 1/2 study evaluated the efficacy and safety of once-daily bosutinib 500 mg in leukemia patients after resistance/intolerance to imatinib. The current analysis included 118 patients with chronic-phase CML who had been pretreated with imatinib followed by dasatinib and/or nilotinib, with a median follow-up of 28.5 months. In this subpopulation, major cytogenetic response was attained by 32% of patients; complete cytogenetic response was attained by 24%, including in one of 3 patients treated with 3 prior TKIs. Complete hematologic response was achieved/maintained in 73% of patients. On-treatment transformation to accelerated/blast phase occurred in 5 patients. At 2 years, Kaplan-Meier–estimated progression-free survival was 73% and estimated overall survival was 83%. Responses were seen across Bcr-Abl mutations, including those associated with dasatinib and nilotinib resistance, except T315I. Bosutinib had an acceptable safety profile; treatment-emergent adverse events were primarily manageable grade 1/2 gastrointestinal events and rash. Grade 3/4 nonhematologic adverse events (> 2% of patients) included diarrhea (8%) and rash (4%). Bosutinib may offer a new treatment option for patients with chronic-phase CML after treatment with multiple TKIs. This trial was registered at www.clinicaltrials.gov as NCT00261846.

scholarly journals Tyrosine kinase inhibitor–induced platelet dysfunction in patients with chronic myeloid leukemia

Blood ◽  
2009 ◽  
Vol 114 (2) ◽  
pp. 261-263 ◽  
Author(s):  
Alfonso Quintás-Cardama ◽  
Xin Han ◽  
Hagop Kantarjian ◽  
Jorge Cortes
Keyword(s):  
Platelet Aggregation ◽  
Chronic Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Kinase Inhibitor ◽  
Chronic Phase ◽  
Platelet Dysfunction ◽  
Normal Platelet ◽  
Closure Time ◽  
Platelet Aggregometry ◽  
Increased Risk

Abstract Dasatinib is associated with increased risk of bleeding among patients with chronic myeloid leukemia, even in the absence of thrombocytopenia, suggesting the presence of a hemostatic defect. We tested platelet aggregation in 91 patients with chronic myeloid leukemia in chronic phase either off-therapy (n = 4) or receiving dasatinib (n = 27), bosutinib (n = 32), imatinib (n = 19), or nilotinib (n = 9). All but 3 patients simultaneously receiving imatinib and warfarin had normal coagulation studies. All 4 patients off therapy had normal platelet aggregation. Impaired platelet aggregation on stimulation with arachidonic acid, epinephrine, or both was observed in 70%, 85%, and 59% of patients on dasatinib, respectively. Eighty-five percent of patients on bosutinib, 100% on nilotinib, and 33% on imatinib had normal platelet aggregation. Dasatinib 400 nM induced rapid and marked prolongation of closure time to collagen/epinephrine in normal whole blood on the PFA-100 system. In conclusion, dasatinib and, to some extent, imatinib produce abnormalities in platelet aggregometry testing.

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