scholarly journals Blasts from patients with acute myelogenous leukemia express functional receptors for stem cell factor

Blood ◽  
1992 ◽  
Vol 80 (1) ◽  
pp. 60-67
Author(s):  
VC Broudy ◽  
FO Smith ◽  
N Lin ◽  
KM Zsebo ◽  
J Egrie ◽  
...  

Stem cell factor (SCF) acts in concert with lineage-specific growth factors to stimulate the growth of hematopoietic colonies. To determine if neoplastic human hematopoietic cells would also respond to SCF, we cultured marrow mononuclear cells from 20 patients with newly diagnosed acute myelogenous leukemia (AML) and two normal donors with SCF, interleukin 3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF), or combinations of growth factors in semisolid medium, and assessed colony growth. SCF receptors (c-kit receptors) were quantitated by equilibrium binding studies with 125I-SCF, and binding parameters were estimated using the ligand program. The cellular distribution of c-kit receptors was determined by autoradiography. Our results show that SCF alone or in combination with IL-3 or GM-CSF increased both the number and size of colonies in 10 of the patients. Receptors for SCF were identified on the blasts from all 20 AML patients. The number of receptors ranged from 600 to 29,000 per cell. In the majority of patients, both high- and low-affinity binding sites were identified. Neither the number of receptors per cell nor the finding of one or two classes of receptors correlated with growth response to SCF. Autoradiographic analysis of 125I-SCF binding to normal marrow mononuclear cells revealed grains associated with blasts and megakaryocytes. Grain counts on blasts from 10 AML patients and on normal marrow blasts suggested that high-affinity c-kit receptor expression on AML blasts is lower than or similar to that of normal blasts. These results identify c-kit receptors on human AML blasts, and indicate that SCF acts synergistically with IL-3 or GM-CSF to stimulate colony growth from the marrow cells of a portion of patients with AML.

Blood ◽  
1992 ◽  
Vol 80 (1) ◽  
pp. 60-67 ◽  
Author(s):  
VC Broudy ◽  
FO Smith ◽  
N Lin ◽  
KM Zsebo ◽  
J Egrie ◽  
...  

Abstract Stem cell factor (SCF) acts in concert with lineage-specific growth factors to stimulate the growth of hematopoietic colonies. To determine if neoplastic human hematopoietic cells would also respond to SCF, we cultured marrow mononuclear cells from 20 patients with newly diagnosed acute myelogenous leukemia (AML) and two normal donors with SCF, interleukin 3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF), or combinations of growth factors in semisolid medium, and assessed colony growth. SCF receptors (c-kit receptors) were quantitated by equilibrium binding studies with 125I-SCF, and binding parameters were estimated using the ligand program. The cellular distribution of c-kit receptors was determined by autoradiography. Our results show that SCF alone or in combination with IL-3 or GM-CSF increased both the number and size of colonies in 10 of the patients. Receptors for SCF were identified on the blasts from all 20 AML patients. The number of receptors ranged from 600 to 29,000 per cell. In the majority of patients, both high- and low-affinity binding sites were identified. Neither the number of receptors per cell nor the finding of one or two classes of receptors correlated with growth response to SCF. Autoradiographic analysis of 125I-SCF binding to normal marrow mononuclear cells revealed grains associated with blasts and megakaryocytes. Grain counts on blasts from 10 AML patients and on normal marrow blasts suggested that high-affinity c-kit receptor expression on AML blasts is lower than or similar to that of normal blasts. These results identify c-kit receptors on human AML blasts, and indicate that SCF acts synergistically with IL-3 or GM-CSF to stimulate colony growth from the marrow cells of a portion of patients with AML.


Blood ◽  
1993 ◽  
Vol 81 (8) ◽  
pp. 2125-2130 ◽  
Author(s):  
S Sekhsaria ◽  
HL Malech

Peripheral blood hematopoietic progenitors (PBHP) are capable of colony growth in vitro. The effect of stem cell factor (SCF), interleukin-6 (IL-6), and basic fibroblast growth factor (bFGF) on myeloid colony proliferation of PBHP was determined. PBHP purified by positive selection with CD34-specific antibody were plated in semisolid agarose with reported plateau doses of interleukin-3 (IL-3), granulocyte- macrophage colony-stimulating factor (GM-CSF), and granulocyte colony- stimulating factor (G-CSF) to enhance myeloid colony growth. Experiments then were done to examine colony growth in response to SCF or with SCF and bFGF and/or IL6. SCF alone in the absence of any other growth factors did not support colony growth. SCF at a determined optimum concentration of 100 ng/mL added to the combination of IL-3, GM- CSF, and G-CSF enhanced colony growth and size relative to proliferation in response to the latter three factors alone (from 78 to 188 total colonies/10(4) PBHP plated and from 10 to 93 large [> 200 cells] colonies/10(4) PBHP plated). Furthermore, addition of bFGF and/or IL-6 to the combination of optimum concentrations of SCF, IL-3, GM-CSF, and G-CSF further enhanced colony number and size in a dose- dependent fashion. Using the optimum combination of all growth factors, we determined that the number of myeloid colony-forming PBHP in whole blood was similar between individuals at about three colonies per milliliter whole blood. We conclude that progenitors capable of responding to the early-acting growth factor, SCF, are represented in PBHP and that the number of circulating myeloid colony-forming PBHP is likely a regulated parameter that may have an important biologic function.


Blood ◽  
1993 ◽  
Vol 81 (8) ◽  
pp. 2125-2130 ◽  
Author(s):  
S Sekhsaria ◽  
HL Malech

Abstract Peripheral blood hematopoietic progenitors (PBHP) are capable of colony growth in vitro. The effect of stem cell factor (SCF), interleukin-6 (IL-6), and basic fibroblast growth factor (bFGF) on myeloid colony proliferation of PBHP was determined. PBHP purified by positive selection with CD34-specific antibody were plated in semisolid agarose with reported plateau doses of interleukin-3 (IL-3), granulocyte- macrophage colony-stimulating factor (GM-CSF), and granulocyte colony- stimulating factor (G-CSF) to enhance myeloid colony growth. Experiments then were done to examine colony growth in response to SCF or with SCF and bFGF and/or IL6. SCF alone in the absence of any other growth factors did not support colony growth. SCF at a determined optimum concentration of 100 ng/mL added to the combination of IL-3, GM- CSF, and G-CSF enhanced colony growth and size relative to proliferation in response to the latter three factors alone (from 78 to 188 total colonies/10(4) PBHP plated and from 10 to 93 large [> 200 cells] colonies/10(4) PBHP plated). Furthermore, addition of bFGF and/or IL-6 to the combination of optimum concentrations of SCF, IL-3, GM-CSF, and G-CSF further enhanced colony number and size in a dose- dependent fashion. Using the optimum combination of all growth factors, we determined that the number of myeloid colony-forming PBHP in whole blood was similar between individuals at about three colonies per milliliter whole blood. We conclude that progenitors capable of responding to the early-acting growth factor, SCF, are represented in PBHP and that the number of circulating myeloid colony-forming PBHP is likely a regulated parameter that may have an important biologic function.


2006 ◽  
Vol 47 (8) ◽  
pp. 1583-1592 ◽  
Author(s):  
Vilmarie Rodriguez ◽  
Peter M. Anderson ◽  
Mark R. Litzow ◽  
Linda Erlandson ◽  
Barbara A. Trotz ◽  
...  

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 883-883 ◽  
Author(s):  
TzuChieh Ho ◽  
Mark W LaMere ◽  
Kristen O'Dwyer ◽  
Jason H. Mendler ◽  
Jane L. Liesveld ◽  
...  

Abstract Acute Myelogenous Leukemia (AML) is a disease that clinically evolves over time as many patients who are responsive to therapy upfront acquire resistance to the same agents when applied in the relapse setting. The stem cell model for AML has been invoked to explain primary resistance to standard therapy; the leukemia stem cell (LSC) population representing a therapy-refractory reservoir for relapse. There have been no prospective efforts to formally assess the evolution of the LSC population during patients’ clinical course. We performed a prospective characterization of specimens from a well-defined cohort of patients with AML at diagnosis and relapse to assess the frequency and phenotype of functionally defined LSCs. Methods Primary bone marrow and peripheral blood samples were collected on IRB approved protocols from patients with newly diagnosed AML undergoing induction therapy. Twenty-five patients who relapsed after achieving a complete remission were selected for further study. Screening studies identified seven patients whose pre-therapy samples demonstrated sustained engraftment of NSG mice following transplantation. Pre-therapy and post-relapse LSC frequencies were assessed using xenotransplantation limiting dilution analyses (LDA). We assessed the frequencies of CD45RA, CD32, TIM-3, CD96, CD47, and CD97 expressing populations that have been previously published to possess LSC activity. Functionally validated pre-therapy and post-relapse LSC populations were identified using fluorescent labeled cell sorting and NSG xenotransplantation. LSC activity was confirmed for each population using secondary xenotransplantation. Gene expression analysis of highly enriched LSC populations from pre-therapy and post-relapse samples was performed using ABI TILDA qPCR analyses following pre-amplification. Results We demonstrated by LDA an 8 to 42-fold increase in LSC frequency between diagnosis and relapse in paired primary patient samples. The increase in LSC activity was not associated with an increase in frequency for phenotypically-defined populations previously reported to possess LSC activity. Rather, we found that LSC activity expanded at relapse to immunophenotypic populations of leukemic cells that did not possess LSC activity prior to treatment. Moreover, in all patients, the number of phenotypically distinct LSC populations (as defined by CD34 and CD38 or CD32 and CD38) detectable at relapse was dramatically expanded. Further, while the majority of the LSC populations’ gene expression profile remained stable between diagnosis and relapse, a subset of genes were enriched in defined LSC populations at relapse including IL3-receptor alpha and IL1-RAP, both previously demonstrated to play a role in LSC biology. Conclusions This study is the first to characterize the natural evolution of LSCs in vivo following treatment and relapse. We demonstrate an increase in LSC activity and greatly increased phenotypic diversity of the LSC population, suggesting a loss of hierarchical organization following relapse. These findings demonstrate that treatment of AML patients with conventional chemotherapy regimens can promote quantitative and qualitative expansion of the LSC compartment. Further, the data indicate that surface antigen immune-phenotype is not predictive of function in relapse and suggest a major limitation to efforts targeting specific surface antigens in the relapse setting. Understanding the mechanisms by which LSC expansion occurs and how to target it will likely improve our currently poor treatment options for patients who relapse. Disclosures: Becker: Millenium: Research Funding.


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