scholarly journals Lack of Expression of Thy-1 (CD90) on Acute Myeloid Leukemia Cells With Long-Term Proliferative Ability In Vitro and In Vivo

Blood ◽  
1997 ◽  
Vol 89 (9) ◽  
pp. 3104-3112 ◽  
Author(s):  
A. Blair ◽  
D.E. Hogge ◽  
L.E. Ailles ◽  
P.M. Lansdorp ◽  
H.J. Sutherland

Abstract Acute myeloid leukaemia (AML) is thought to be maintained by a small population of leukemic progenitor cells. To define the phenotype of such cells with long-term proliferative capacity in vitro and in vivo, we have used the production of leukemic clonogenic cells (CFU) after 2 to 8 weeks in suspension culture as a measure of these cells in vitro and compared their phenotype with that of cells capable of engrafting nonobese diabetic severe combined immune deficient (NOD/SCID) mice. Leukemic blast peripheral blood cells were evaluated for expression of CD34 and Thy-1 (CD90) antigens. The majority of AML blast cells at diagnosis lacked expression of Thy-1. Most primary CFU-blast and the CFU detected at up to 8 weeks from suspension cultures were CD34+/Thy-1−. AML cells that were capable of engrafting NOD/SCID mice were also found to have the CD34+/Thy-1− phenotype. However, significant engraftment was achieved using both CD34+/Thy-1− and CD34− subfractions from one AML M5 patient. These results suggest that while heterogeneity exists between individual patients, the leukemic progenitor cells that are capable of maintaining the disease in vitro and in vivo differ from normal hematopoietic progenitor cells in their lack of expression of Thy-1.

Blood ◽  
1998 ◽  
Vol 92 (11) ◽  
pp. 4325-4335 ◽  
Author(s):  
A. Blair ◽  
D.E. Hogge ◽  
H.J. Sutherland

Acute myeloid leukemia (AML) occurs as the result of malignant transformation in a hematopoietic progenitor cell, which proliferates to form an accumulation of AML blasts. Only a minority of these AML cells are capable of proliferation in vitro, suggesting that AML cells may be organized in a hierarchy, with only the most primitive of these cells capable of maintaining the leukemic clone. To further investigate this hypothesis, we have evaluated a strategy for purifying these primitive cells based on surface antigen expression. As an in vitro endpoint, we have determined the phenotype of AML progenitor cells which are capable of producing AML colony-forming cells (CFU) for up to 8 weeks in suspension culture (SC) and compared the phenotype with that of cells which reproduce AML in nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice. AML cells were fluorescence-activated cell sorted (FACS) for coexpression of CD34 and CD71, CD38, and/or HLA-DR and the subfractions were assayed in vitro and in vivo at various cell doses to estimate purification. While the majority of primary AML CFU lacked expression of CD34, most cells capable of producing CFU after 2 to 8 weeks in SC were CD34+/CD71−. HLA-DR expression was heterogeneous on cells producing CFU after 2 to 4 weeks. However, after 6 to 8 weeks in SC, the majority of CFU were derived from CD34+/HLA-DR− cells. Similarly, the majority of cells capable of long-term CFU production from SC were CD34+/CD38−. Most cells that were capable of engrafting NOD/SCID mice were also CD34+/CD71− and CD34+/HLA-DR−. Engraftment was not achieved with CD34+/CD71+ or HLA-DR+subfractions, however, in two patients, both the CD34+and CD34− subfractions were capable of engrafting the NOD/SCID mice. A three-color sorting strategy combining these antigens allowed approximately a 2-log purification of these NOD/SCID leukemia initiating cells, with engraftment achieved using as few as 400 cells in one experiment. Phenotyping studies suggest even higher purification could be achieved by combining lack of CD38 expression with the CD34+/CD71− or CD34+/HLA DR− phenotype. These results suggest that most AML cells capable of long-term proliferation in vitro and in vivo share the CD34+/CD71−/HLA-DR− phenotype with normal stem cells. Our data suggests that in this group of patients the leukemic transformation has occurred in a primitive progenitor, as defined by phenotype, with some degree of subsequent differentiation as defined by functional assays.


Blood ◽  
1998 ◽  
Vol 92 (11) ◽  
pp. 4325-4335 ◽  
Author(s):  
A. Blair ◽  
D.E. Hogge ◽  
H.J. Sutherland

Abstract Acute myeloid leukemia (AML) occurs as the result of malignant transformation in a hematopoietic progenitor cell, which proliferates to form an accumulation of AML blasts. Only a minority of these AML cells are capable of proliferation in vitro, suggesting that AML cells may be organized in a hierarchy, with only the most primitive of these cells capable of maintaining the leukemic clone. To further investigate this hypothesis, we have evaluated a strategy for purifying these primitive cells based on surface antigen expression. As an in vitro endpoint, we have determined the phenotype of AML progenitor cells which are capable of producing AML colony-forming cells (CFU) for up to 8 weeks in suspension culture (SC) and compared the phenotype with that of cells which reproduce AML in nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice. AML cells were fluorescence-activated cell sorted (FACS) for coexpression of CD34 and CD71, CD38, and/or HLA-DR and the subfractions were assayed in vitro and in vivo at various cell doses to estimate purification. While the majority of primary AML CFU lacked expression of CD34, most cells capable of producing CFU after 2 to 8 weeks in SC were CD34+/CD71−. HLA-DR expression was heterogeneous on cells producing CFU after 2 to 4 weeks. However, after 6 to 8 weeks in SC, the majority of CFU were derived from CD34+/HLA-DR− cells. Similarly, the majority of cells capable of long-term CFU production from SC were CD34+/CD38−. Most cells that were capable of engrafting NOD/SCID mice were also CD34+/CD71− and CD34+/HLA-DR−. Engraftment was not achieved with CD34+/CD71+ or HLA-DR+subfractions, however, in two patients, both the CD34+and CD34− subfractions were capable of engrafting the NOD/SCID mice. A three-color sorting strategy combining these antigens allowed approximately a 2-log purification of these NOD/SCID leukemia initiating cells, with engraftment achieved using as few as 400 cells in one experiment. Phenotyping studies suggest even higher purification could be achieved by combining lack of CD38 expression with the CD34+/CD71− or CD34+/HLA DR− phenotype. These results suggest that most AML cells capable of long-term proliferation in vitro and in vivo share the CD34+/CD71−/HLA-DR− phenotype with normal stem cells. Our data suggests that in this group of patients the leukemic transformation has occurred in a primitive progenitor, as defined by phenotype, with some degree of subsequent differentiation as defined by functional assays.


Blood ◽  
1996 ◽  
Vol 87 (6) ◽  
pp. 2187-2194 ◽  
Author(s):  
W Terpstra ◽  
A Prins ◽  
RE Ploemacher ◽  
BW Wognum ◽  
G Wagemaker ◽  
...  

Acute myeloid leukemia (AML) proliferation in vivo is maintained by a small fraction of progenitor cells. These cells have been assumed to express an immature phenotype and to produce most colony-forming units (CFU-AML). For one case of AML (French-American-British [FAB] M1, normal cytogenetics), we examined the capacity of the CD34+ (25% of unseparated AML cells) and CD34- fractions to initiate leukemia in severe combined immunodeficient (SCID) mice. In addition, the production of CFU-AML and nucleated cells (NC) of these subsets was investigated in long-term bone marrow culture (LTBMC). The frequencies of cobblestone area-forming cells (CAFC) were also estimated; early appearing cobblestone areas (CAs) are indicative of relatively mature progenitors and late CAs represent the progeny of primitive progenitors. In mice transplanted with CD34- (98% pure) or CD34+ (98% pure) grafts, similar AML cell growth was seen throughout an observation period of 106 days. The capacity to establish long-term growth from the CD34- cells was confirmed by renewed outgrowth after retransplantation. In vitro, the CD34- fraction contained both immature and mature CAFCs and produced high numbers of CFU-AML and NC in LTBMC. The CD34+ fraction produced only small numbers of CFU-AML, NC, and mature CAFCs. Therefore, the expression of CD34 and the content of CFU- AML were not associated with long-term growth of AML. However, similar frequencies of primitive CAFCs were observed in both fractions. Thus, both CD34- and CD34+ subsets of this AML sample contained immature progenitors with the capacity to initiate long-term AML growth as characterized in vivo (in SCID mice) as well as in vitro (in CAFC assay), indicating asynchrony between functional and immunophenotypical maturation of AML progenitor cell compartments.


Blood ◽  
2011 ◽  
Vol 117 (18) ◽  
pp. 4773-4777 ◽  
Author(s):  
Hal E. Broxmeyer ◽  
Man-Ryul Lee ◽  
Giao Hangoc ◽  
Scott Cooper ◽  
Nutan Prasain ◽  
...  

Abstract Cryopreservation of hematopoietic stem cells (HSCs) and hematopoietic progenitor cells (HPCs) is crucial for cord blood (CB) banking and transplantation. We evaluated recovery of functional HPC cryopreserved as mononuclear or unseparated cells for up to 23.5 years compared with prefreeze values of the same CB units. Highly efficient recovery (80%-100%) was apparent for granulocyte-macrophage and multipotential hematopoietic progenitors, although some collections had reproducible low recovery. Proliferative potential, response to multiple cytokines, and replating of HPC colonies was extensive. CD34+ cells isolated from CB cryopreserved for up to 21 years had long-term (≥ 6 month) engrafting capability in primary and secondary immunodeficient mice reflecting recovery of long-term repopulating, self-renewing HSCs. We recovered functionally responsive CD4+ and CD8+ T lymphocytes, generated induced pluripotent stem (iPS) cells with differentiation representing all 3 germ cell lineages in vitro and in vivo, and detected high proliferative endothelial colony forming cells, results of relevance to CB biology and banking.


Leukemia ◽  
2021 ◽  
Author(s):  
Madeline Niederkorn ◽  
Chiharu Ishikawa ◽  
Kathleen M. Hueneman ◽  
James Bartram ◽  
Emily Stepanchick ◽  
...  

AbstractUbiquitin-specific peptidase 15 (USP15) is a deubiquitinating enzyme implicated in critical cellular and oncogenic processes. We report that USP15 mRNA and protein are overexpressed in human acute myeloid leukemia (AML) as compared to normal hematopoietic progenitor cells. This high expression of USP15 in AML correlates with KEAP1 protein and suppression of NRF2. Knockdown or deletion of USP15 in human and mouse AML models significantly impairs leukemic progenitor function and viability and de-represses an antioxidant response through the KEAP1-NRF2 axis. Inhibition of USP15 and subsequent activation of NRF2 leads to redox perturbations in AML cells, coincident with impaired leukemic cell function. In contrast, USP15 is dispensable for human and mouse normal hematopoietic cells in vitro and in vivo. A preclinical small-molecule inhibitor of USP15 induced the KEAP1-NRF2 axis and impaired AML cell function, suggesting that targeting USP15 catalytic function can suppress AML. Based on these findings, we report that USP15 drives AML cell function, in part, by suppressing a critical oxidative stress sensor mechanism and permitting an aberrant redox state. Furthermore, we postulate that inhibition of USP15 activity with small molecule inhibitors will selectively impair leukemic progenitor cells by re-engaging homeostatic redox responses while sparing normal hematopoiesis.


Blood ◽  
1986 ◽  
Vol 68 (1) ◽  
pp. 41-45 ◽  
Author(s):  
R Delwel ◽  
I Touw ◽  
F Bot ◽  
B Lowenberg

Abstract The reactivity of acute myeloid leukemia cells (AML) was determined in 29 patients using the fucose binding lectin Ulex europaeus agglutinin (UEA) as surface marker. We show a marked heterogeneity in the UEA- binding abilities of the cells in these patients as determined by fluorescence analysis of the blasts labeled with the UEA coupled to the fluorescent molecule FITC. The results suggest a correlation between the capability of AML blast cells to bind UEA and cytologic maturation, because in 1 of 10 M1, 3 of 8 M2, 6 of 8 M4, and 1 of 3 M5 cytology types UEA binding to the leukemic cells was apparent. In 13 cases, the cells gave rise to colonies in vitro. The amount of UEA binding to AML colony-forming cells (AML-CFU) was determined by cell sorting and subsequent colony culture of UEA-negative, intermediately positive, and highly fluorescent cells. AML-CFU from none of the four patients with M1 cytology were UEA positive, whereas they showed intense reactivity with the lectin in 1 of 4 cases with M2 cytology and in all 4 cases of M4. In these five cases with strongly UEA positive AML-CFU, the fluorescence distribution of the colony formers differed from that of the total leukemia population, indicating that AML-CFU represent a subpopulation of AML cells with specific UEA-binding properties. Normal bone marrow myeloid and multipotential colony-forming cells (CFU-GM, CFU-GEMM) showed low or no binding of UEA. UEA-FITC appears a useful reagent for membrane analysis of AML-CFU. In certain cases, UEA-FITC labeling may be applied to discriminate AML-CFU from normal hematopoietic progenitors.


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