Acute myeloid leukemia (AML) is organized as a cellular hierarchy initiated and maintained by a subset of self-renewing leukemia stem cells (LSC). We hypothesized that increased CD47 expression on human AML LSC contributes to pathogenesis by inhibiting their phagocytosis through the interaction of CD47 with an inhibitory receptor on phagocytes. We found that CD47 was more highly expressed on AML LSC than their normal counterparts, and that increased CD47 expression predicted worse overall survival in three independent cohorts of adult AML patients. Furthermore, blocking monoclonal antibodies directed against CD47 preferentially enabled phagocytosis of AML LSC and inhibited their engraftment in vivo. Finally, treatment of human AML LSC-engrafted mice with anti-CD47 antibody depleted AML and targeted AML LSC. In summary, increased CD47 expression is an independent, poor prognostic factor that can be targeted on human AML stem cells with blocking monoclonal antibodies capable of enabling phagocytosis of LSC.
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http://dx.doi.org/10.1016/j.cell.2009.05.045 | DOI Listing |
Blood
January 2025
1Princess Margaret Cancer Centre, University Health Network; Toronto, ON M5G 1L7, Canada 14Department of Molecular Genetics, University of Toronto; Toronto, ON, Canada, Canada.
Leukemic stem cells (LSCs) fuel acute myeloid leukemia (AML) growth and relapse, but therapies tailored towards eradicating LSCs without harming normal hematopoietic stem cells (HSCs) are lacking. FLT3 is considered an important therapeutic target due to frequent mutation in AML and association with relapse. However, there has been limited clinical success with FLT3 drug targeting, suggesting either that FLT3 is not a vulnerability in LSC, or that more potent inhibition is required, a scenario where HSC toxicity could become limiting.
View Article and Find Full Text PDFR Soc Open Sci
January 2025
Department of Anatomy, Kanazawa Medical University, Uchinada, Ishikawa 9200293, Japan.
Acute myeloid leukaemia (AML) is a haematologic malignancy with high relapse rates in both adults and children. Leukaemic stem cells (LSCs) are central to leukaemopoiesis, treatment response and relapse and frequently associated with measurable residual disease (MRD). However, the dynamics of LSCs within the AML microenvironment is not fully understood.
View Article and Find Full Text PDFExpert Rev Hematol
January 2025
Department of Internal Medicine III, Ulm University Hospital, Ulm, Germany.
Introduction: Leukemic stem cells (LSC) are the source of relapse in acute myeloid leukemia (AML). Thus, eliminating LSC is one of the overarching goals of AML research. Radioimmunotherapy is an immunotherapeutic approach which utilizes radioactive isotopes as effector molecules based on the proven ability of ionizing radiation (IR) to kill LSC.
View Article and Find Full Text PDFExp Hematol Oncol
December 2024
Department of Hematologic Malignancies Translational Science, Beckman Research Institute and City of Hope National Medical Center, Duarte, CA, USA.
Cytoplasmic proliferating cell nuclear antigen (PCNA) is highly expressed in acute myeloid leukemia (AML) cells, supporting oxidative metabolism and leukemia stem cell (LSC) growth. We report on AOH1996 (AOH), an oral compound targeting cancer-associated PCNA, which shows significant antileukemic activity. AOH inhibited growth in AML cell lines and primary CD34 + CD38 - blasts (LSC-enriched) in vitro while sparing normal hematopoietic stem cells (HSCs).
View Article and Find Full Text PDFCancer Sci
December 2024
Department of Medicine and Biosystemic Science, Kyushu University Graduate School of Medicine, Fukuoka, Japan.
In this study, we investigated the measurable residual leukemic stem cell (MR-LSC) population after allogeneic stem cell transplantation (allo-SCT) for high-risk acute myeloid leukemia (AML), utilizing T-cell immunoglobulin mucin-3 (TIM-3) expression as a functional marker of AML leukemic stem cells (LSCs). Analysis of the CD34CD38 fraction of bone marrow cells immediately after achievement of engraftment revealed the presence of both TIM-3LSCs and TIM-3 donor hematopoietic stem cells (HSCs) at varying ratios. Genetic analysis confirmed that TIM-3 cells harbored patient-specific mutations identical to those found in AML clones, whereas TIM-3 cells did not, indicating that TIM-3CD34CD38 cells represent residual AML LSCs.
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