The Kinetics and Extent of Engraftment of Chronic Myelogenous Leukemia Cells in Non-Obese Diabetic/Severe Combined Immunodeficiency Mice Reflect the Phase of the Donor’s Disease: An In Vivo Model of Chronic Myelogenous Leukemia Biology

Blood ◽  
1998 ◽  
Vol 92 (4) ◽  
pp. 1390-1396 ◽  
Author(s):  
Francesco Dazzi ◽  
Debora Capelli ◽  
Robert Hasserjian ◽  
Finbarr Cotter ◽  
Margherita Corbo ◽  
...  
Keyword(s):  
Cell Line ◽  
Chronic Myelogenous Leukemia ◽  
Chronic Phase ◽  
Human Cells ◽  
Scid Mice ◽  
Myelogenous Leukemia ◽  
In Vivo Model ◽  
Fish Analysis ◽  
Rate Of Increase

Abstract In vitro studies have provided little consensus on the kinetic abnormality underlying the myeloid expansion of chronic myelogenous leukemia (CML). Transplantation of human CML cells into non-obese diabetic mice with severe immunodeficiency disease (NOD/SCID mice) may therefore be a useful model. A CML cell line (BV173) and peripheral blood cells collected from CML patients in chronic phase (CP), accelerated phase (AP), or blastic phase (BP) were injected into preirradiated NOD/SCID mice. Animals were killed at serial intervals; cell suspensions and/or tissue sections from different organs were studied by immunohistochemistry and/or flow cytometry using antihuman CD45 monoclonal antibodies (MoAbs), and by fluorescence in situ hybridization (FISH) for the BCR-ABL fusion gene. One hour after injection, cells were sequestered in the lungs and liver, but 2 weeks later they were no longer detectable in either site. Similar short-term kinetics were observed using51Cr-labeled cells. The first signs of engraftment for BV173, AP, and BP cells were detected in the bone marrow (BM) at 4 weeks. At 8 weeks the median percentages of human cells in murine marrow were 4% (range, 1 to 9) for CP, 11% (range, 5 to 36) for AP, 38.5% (range, 18 to 79) for BP, and 54% (range, 31 to 69) for BV173. CP cells progressively infiltrated BM (21%) and spleen (6%) by 18 to 20 weeks; no animals injected with the cell line or BP cells survived beyond 12 weeks. The rate of increase in human cell numbers was higher for BP (7.3%/week) as compared with CP (0.9%/week) and AP (0.5%/week). FISH analysis with BCR and ABL probes showed that some of the human cells engrafting after injection of CP cells lacked a BCR-ABL gene and were presumably normal. We conclude that CML cells proliferate in NOD/SCID mice with kinetics that recapitulate the phase of the donor’s disease, thus providing an in vivo model of CML biology. © 1998 by The American Society of Hematology.

The Kinetics and Extent of Engraftment of Chronic Myelogenous Leukemia Cells in Non-Obese Diabetic/Severe Combined Immunodeficiency Mice Reflect the Phase of the Donor’s Disease: An In Vivo Model of Chronic Myelogenous Leukemia Biology

Blood ◽  
1998 ◽  
Vol 92 (4) ◽  
pp. 1390-1396 ◽  
Author(s):  
Francesco Dazzi ◽  
Debora Capelli ◽  
Robert Hasserjian ◽  
Finbarr Cotter ◽  
Margherita Corbo ◽  
...  
Keyword(s):  
Cell Line ◽  
Chronic Myelogenous Leukemia ◽  
Chronic Phase ◽  
Human Cells ◽  
Scid Mice ◽  
Myelogenous Leukemia ◽  
In Vivo Model ◽  
Fish Analysis ◽  
Rate Of Increase

In vitro studies have provided little consensus on the kinetic abnormality underlying the myeloid expansion of chronic myelogenous leukemia (CML). Transplantation of human CML cells into non-obese diabetic mice with severe immunodeficiency disease (NOD/SCID mice) may therefore be a useful model. A CML cell line (BV173) and peripheral blood cells collected from CML patients in chronic phase (CP), accelerated phase (AP), or blastic phase (BP) were injected into preirradiated NOD/SCID mice. Animals were killed at serial intervals; cell suspensions and/or tissue sections from different organs were studied by immunohistochemistry and/or flow cytometry using antihuman CD45 monoclonal antibodies (MoAbs), and by fluorescence in situ hybridization (FISH) for the BCR-ABL fusion gene. One hour after injection, cells were sequestered in the lungs and liver, but 2 weeks later they were no longer detectable in either site. Similar short-term kinetics were observed using51Cr-labeled cells. The first signs of engraftment for BV173, AP, and BP cells were detected in the bone marrow (BM) at 4 weeks. At 8 weeks the median percentages of human cells in murine marrow were 4% (range, 1 to 9) for CP, 11% (range, 5 to 36) for AP, 38.5% (range, 18 to 79) for BP, and 54% (range, 31 to 69) for BV173. CP cells progressively infiltrated BM (21%) and spleen (6%) by 18 to 20 weeks; no animals injected with the cell line or BP cells survived beyond 12 weeks. The rate of increase in human cell numbers was higher for BP (7.3%/week) as compared with CP (0.9%/week) and AP (0.5%/week). FISH analysis with BCR and ABL probes showed that some of the human cells engrafting after injection of CP cells lacked a BCR-ABL gene and were presumably normal. We conclude that CML cells proliferate in NOD/SCID mice with kinetics that recapitulate the phase of the donor’s disease, thus providing an in vivo model of CML biology. © 1998 by The American Society of Hematology.

Fas-Mediated Modulation of Bcr/Abl in Chronic Myelogenous Leukemia Results in Differential Effects on Apoptosis

Blood ◽  
1998 ◽  
Vol 92 (3) ◽  
pp. 981-989 ◽  
Author(s):  
Carmine Selleri ◽  
Jaroslaw P. Maciejewski ◽  
Fabrizio Pane ◽  
Luigia Luciano ◽  
Anna Maria Raiola ◽  
...  
Keyword(s):  
Chronic Myelogenous Leukemia ◽  
Chronic Phase ◽  
Poor Response ◽  
Inhibitory Response ◽  
Myelogenous Leukemia ◽  
Poor Responders ◽  
Cd34 Cells ◽  
In Cells

Abstract Fas-R is expressed constitutively in CD34+ cells of patients with chronic myelogenous leukemia (CML); Fas-R triggering results in decreased proliferation rate due to apoptosis of clonogenic cells. We have already shown that α-interferon (IFN-α) enhances Fas-R expression on CML progenitor cells, thus increasing their sensitivity to Fas-R agonists. Although it appears that IFN-α can prime CML cells for the effects of Fas, the response to IFN-α in vivo is not a constant feature in CML patients. We studied the mechanisms of Fas-mediated apoptosis in 11 patients suffering from CML in chronic phase and tried to see whether there was a correlation between in vitro inducibility of apoptosis in CD34+ CML cells after Fas-R triggering and the clinical response to IFN-α. After priming with IFN-α, Fas triggering resulted in in vitro suppression of hematopoietic cell growth in seven of eight patients who had optimal hematologic response to IFN-α; in the same conditions, no inhibitory response to Fas-R agonist was observed in cells from three of three patients who proved to be poor responders to IFN-α. In responders to IFN-α, Fas-R agonist induced dose-dependent apoptosis of CD34+ cells; this effect was associated with a decrease in the bcr/abl protein level. In cells derived from patients with a poor response to IFN-α, the rate of apoptosis in culture remained unchanged in the presence of Fas-R agonist and nobcr/abl downmodulation was observed. Finally, we measuredbcr/abl mRNA by quantitative reverse-transcriptase polymerase chain reaction (RT-PCR) and found that decreased bcr/ablprotein after Fas triggering was not associated with decreased amounts of specific mRNA, a finding which is consistent with a posttranscriptional regulation of the bcr/abl protein expression. It appears that Fas-mediated downmodulation of p210bcr/abl restores susceptibility to apoptosis of CML cells; in addition, in vitro studies on CML cells may predict response to IFN-α treatment. © 1998 by The American Society of Hematology.

scholarly journals Normal and leukemic SCID-repopulating cells (SRC) coexist in the bone marrow and peripheral blood from CML patients in chronic phase, whereas leukemic SRC are detected in blast crisis

Blood ◽  
1996 ◽  
Vol 87 (4) ◽  
pp. 1539-1548 ◽  
Author(s):  
C Sirard ◽  
T Lapidot ◽  
J Vormoor ◽  
JD Cashman ◽  
M Doedens ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Animal Model ◽  
Peripheral Blood ◽  
Blast Crisis ◽  
Chronic Phase ◽  
Human Cells ◽  
Scid Mice ◽  
Myelogenous Leukemia ◽  
Normal Cells ◽  
Starting Point

Progress in understanding the abnormal regulation of hematopoiesis in chronic myelogenous leukemia (CML) would be facilitated if neoplastic cells, at all stages of the disease, could be studied in an animal model. In this report, we show that irradiated severe combined immunodeficient (SCID) mice can be transplanted with both normal (Philadelphia chromosome [Ph]-negative) and neoplastic (Ph+) cells from CML patients with either chronic or blast phase disease. Mice transplanted with peripheral blood (PB) or bone marrow (BM) cells from 9 of 12 chronic phase CML patients were well engrafted with human cells including multilineage colony-forming progenitors and CD34+ cells for at least 90 days posttransplantation. Repeated posttransplant injections of cytokines did not enhance the number of engrafted human cells. Interestingly, approximately 70% of the human progenitors found in the engrafted SCID BM were Ph-, suggesting that the growth of primitive normal cells is favored in this in vivo transplant model. A similar number of normal cells were found in mice transplanted with either PB or BM cells, suggesting that elevated numbers of primitive normal cells are present in CML PB. When cells from patients with CML in either myeloid or lymphoid blast crisis were transplanted into SCID mice, the BM of these mice was more rapidly repopulated and to a higher level than that observed with transplants of chronic phase cells. Moreover, all human colony-forming progenitors present in the BM of mice transplanted with blast crisis cells were Ph+, and the majority of cells showed the same morphological features of the blast crisis cells originally transplanted. These experiments provide a starting point for the creation of an animal model of CML and establish the feasibility of using this model for the future characterization of transplantable CML stem cells during disease progression.

scholarly journals Acute- and chronic-phase chronic myelogenous leukemia colony-forming units are highly sensitive to the growth inhibitory effects of c-myb antisense oligodeoxynucleotides

Blood ◽  
1992 ◽  
Vol 79 (8) ◽  
pp. 1956-1961 ◽  
Author(s):  
MZ Ratajczak ◽  
N Hijiya ◽  
L Catani ◽  
K DeRiel ◽  
SM Luger ◽  
...  
Keyword(s):  
Chronic Myelogenous Leukemia ◽  
Colony Formation ◽  
Ex Vivo ◽  
Blast Crisis ◽  
Chronic Phase ◽  
Myelogenous Leukemia ◽  
Antisense Oligodeoxynucleotides ◽  
Rt Pcr ◽  
Colony Forming Units

Abstract We have previously demonstrated that malignant hematopoietic colony- forming units (CFUs) may be purged from normal CFU by exposure to c-myb antisense oligodeoxynucleotides (oligomers). This novel strategy appeared particularly promising for patients with chronic myelogenous leukemia (CML) in blast crisis, since in some cases complete elimination of bcr-abl-expressing cells was accomplished. We have examined 11 additional patients, including seven in chronic phase, in order to extend these initial observations. We sought in particular to determine if elimination of bcr-abl-expressing clones was a usual event. Exposure of CML cells to c-myb antisense oligomers resulted in inhibition of CFU-granulocyte, macrophage (CFU-GM)-derived colony formation in eight of 11 (73%) cases evaluated. Inhibition was antisense sequence-specific, dose-dependent, ranged between 58% and 93%, and was statistically significant (P less than or equal to .03) in seven of the eight cases. In two cases, CFU-granulocyte, erythrocyte, monocyte, megakaryocyte (CFU-GEMM)-derived colony formation was also examined and found to be inhibited by the c-myb antisense oligomers in a sequence-specific manner. To determine whether CML CFU had been reduced or eliminated after exposure to the antisense oligomers, we examined cells in the residual colonies for bcr-abl mRNA expression using a reverse transcription-polymerase chain reaction detection technique (RT-PCR). Eight cases were evaluated and in each case where antisense myb inhibited growth, bcr-abl expression as detected by RT- PCR was either greatly decreased or nondetectable. No residual leukemic CFU were demonstrable on replating of treated cells. These results suggest that c-myb antisense oligomers substantially inhibit the growth and survival of CML CFU in both chronic and blast phase of disease. They may therefore prove useful for both ex vivo and in vivo treatment of CML.

Multi-Targeted Receptor Tyrosine Kinase Inhibitor, ABT-869, Induces Apoptosis and Inhibition of Proliferation of Ba/F3 FLT-3 ITD Mutant Cells.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1589-1589
Author(s):  
Jenny E. Hernandez ◽  
Junling Li ◽  
Ru-Qi Wei ◽  
Paul Tapang ◽  
Steven K. Davidsen ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Cell Line ◽  
Cell Lines ◽  
Receptor Tyrosine Kinase ◽  
Mutant Cell ◽  
Scid Mice ◽  
Myelogenous Leukemia ◽  
Parp Cleavage ◽  
Mutant Cells

Abstract FLT3 is an receptor tyrosine kinase of the subclass III family that plays a vital role in the regulation of the differentiation, proliferation and survival of normal hematopoietic cells. FLT3 mutations are often found in patients with Acute myelogenous leukemia (AML) and confer poor prognosis. Of these mutations, 15–35% are FLT3 ITD (internal tandem duplication) mutations and 5–7% are point mutations on the FLT3 kinase activation loop (e.g. D835V). Our laboratory is studying the signaling pathways associated with a newly identified multi-targeted tyrosine kinase receptor small molecule inhibitor (RTKI), ABT-869. Recently published work in our laboratory showed that using ABT-869 to treat MV4-11, a human AML FLT-3 ITD mutant cell line, resulted in the inhibition of phosphorylation of FLT-3 with a downstream inhibitory effect on the activation of STAT5, ERK, and Pim-1. Cell viability assays determined that MV-411 cells responded to ABT-869 in a concentration dependent manner (IC50 = 10nM). Apoptosis studies also showed an induction of apoptosis in ABT-869 treated cells. In vivo studies involving xenograft injections of MV-411 cells into SCID mice and subsequent treatment with ABT-869 demonstrated regression of tumor formation. In this study, a Ba/F3 mouse pro-B lymphocytic cell line harboring the FLT-3 ITD or FLT-3 D835V mutation is used as an isolated Flt-3 mutant model system. In vitro, ABT-869 is effective in inhibiting the proliferation of Ba/F3 Flt-3 ITD mutant cells when compared to Ba/F3 Flt-3 D835V mutant and Ba/F3 Flt-3 WT cells. Trypan Blue Exclusion and Alamar Blue assays were used to demonstrate that there is 50% inhibition of growth and proliferation (IC50) of Ba/F3 FLT3 ITD mutant cells at a concentration of 1nM after 48 hours of treatment. Ba/F3 FLT3 D835V mutant cells show an IC50 between 1μM and 10μM after 48 hours of treatment. In contrast, Ba/F3 FLT3 WT cells demonstrate an IC50 of 10μM only after 72 hours of treatment. Annexin V and propidium iodide staining of cells revealed that an increase in apoptosis (41.2%) occurred in Ba/F3 Flt-3 ITD mutant cells treated with 10nM ABT-869 after 24 hours when compared to untreated (6.5%) or vehicle control (6.1%) cells. Staining of Ba/F3 Flt-3 WT treated cell lines revealed no difference in apoptosis when compared to untreated Ba/F3 Flt-3 WT cell only and DMSO controls. PARP cleavage was observed in Ba/F3 FLT-3 ITD mutant cells following treatment with ABT-869 whereas no cleavage was observed with Ba/F3 WT cells treated with ABT-869. In vivo, the activity of ABT-869 treatment of SCID mice injected with Baf3 Flt-3 ITD, Baf3 Flt-3 D835V, or Baf3 Flt-3 WT cells is also being evaluated. Using bioluminescence imaging, it was determined that Ba/F3 FLT-3 ITD mutant and Ba/F3 Flt-3 D835Vmutant cell lines result in metastases and subsequent death in SCID mice after 2 weeks for ITD and 5 weeks for D835V, whereas mice injected with Ba/F3 WT survive longer than 5 weeks. Preliminary data demonstrated that ABT-869 prolonged survival in mice injected with the Ba/F3 FLT3-ITD cells compared to controls. Our preclinical data demonstrate that ABT-869 is effective specifically with FLT-3 ITD mutant cell lines in an isolated system. These studies provide rationale for the treatment of AML patients and the prevention of relapse.

scholarly journals Comparative Analysis of Autografting in Chronic Myelogenous Leukemia: Effects of Priming Regimen and Marrow or Blood Origin of Stem Cells

Blood ◽  
1998 ◽  
Vol 92 (5) ◽  
pp. 1820-1831
Author(s):  
Catherine M. Verfaillie ◽  
Ravi Bhatia ◽  
Michael Steinbuch ◽  
Todd DeFor ◽  
Betsy Hirsch ◽  
...  
Keyword(s):  
Chronic Myelogenous Leukemia ◽  
Philadelphia Chromosome ◽  
Chronic Phase ◽  
Cytogenetic Response ◽  
Myelogenous Leukemia ◽  
Disease Stage ◽  
Hla Dr ◽  
Before And After ◽  
American Society

The aims of this study were (1) to evaluate the effect of intermediate (cyclophosphamide alone) or intensive (mitoxantrone, cytosine arabinoside, cyclophosphamide) priming on the cytogenetic response in mobilized bone marrow (BM) or peripheral blood (PB) progenitors in patients with chronic myelogenous leukemia (CML), (2) to determine the incidence of cytogenetic remissions after mobilized progenitor transplantation in CML, and (3) to determine the effect of in vivo priming on the ability to select Philadelphia chromosome–negative (Ph-negative) CD34+HLA-DR− cells from mobilized BM or PB in quantities sufficient for transplantation. Between February 1994 and March 1997, 44 patients were enrolled in three sequential protocols. Although the duration of neutropenia after only cyclophosphamide mobilization was shorter, clinical morbidity for the intermediate and intensive priming protocols was similar. Cytogenetic responses in mobilized PB progenitors were similar after mobilization with either intermediate or intensive chemotherapy. The degree of Ph negativity in the mobilized product correlated with disease stage at the time of mobilization (early chronic phase [ECP] > late CP > accelerated phase). Cytogenetic responses after transplantation with mobilized progenitors obtained after the different regimens were similar. The cytogenetic status of the graft predicted the cytogenetic status of marrow obtained 3 weeks after transplantation whereas cytogenetic responses 3, 6, and 12 months after transplantation correlated with the number of BCR/ABL–negative CD34+HLA-DR−cells, but not the number of Ph-negative metaphases in the graft. In patients with ECP CML, mobilized PB collections yielded significantly more CD34+HLA-DR− cells than from steady state or mobilized BM. CD34+HLA-DR− cells were Ph negative and polyclonal (X-chromosome inactivation) in the majority of ECP CML patients, before and after mobilization and irrespective of the mobilization regimen. Because infusion of large numbers of Ph-negative CD34+HLA-DR− cells predicted superior outcome after transplantation, approaches in which CD34+HLA-DR− cells are selected from mobilized PB may result in longer lasting and clinically significant cytogenetic responses after transplantation. © 1998 by The American Society of Hematology.

Comparative Analysis of Autografting in Chronic Myelogenous Leukemia: Effects of Priming Regimen and Marrow or Blood Origin of Stem Cells

Blood ◽  
1998 ◽  
Vol 92 (5) ◽  
pp. 1820-1831 ◽  
Author(s):  
Catherine M. Verfaillie ◽  
Ravi Bhatia ◽  
Michael Steinbuch ◽  
Todd DeFor ◽  
Betsy Hirsch ◽  
...  
Keyword(s):  
Chronic Myelogenous Leukemia ◽  
Philadelphia Chromosome ◽  
Chronic Phase ◽  
Cytogenetic Response ◽  
Myelogenous Leukemia ◽  
Disease Stage ◽  
Hla Dr ◽  
Before And After ◽  
American Society

Abstract The aims of this study were (1) to evaluate the effect of intermediate (cyclophosphamide alone) or intensive (mitoxantrone, cytosine arabinoside, cyclophosphamide) priming on the cytogenetic response in mobilized bone marrow (BM) or peripheral blood (PB) progenitors in patients with chronic myelogenous leukemia (CML), (2) to determine the incidence of cytogenetic remissions after mobilized progenitor transplantation in CML, and (3) to determine the effect of in vivo priming on the ability to select Philadelphia chromosome–negative (Ph-negative) CD34+HLA-DR− cells from mobilized BM or PB in quantities sufficient for transplantation. Between February 1994 and March 1997, 44 patients were enrolled in three sequential protocols. Although the duration of neutropenia after only cyclophosphamide mobilization was shorter, clinical morbidity for the intermediate and intensive priming protocols was similar. Cytogenetic responses in mobilized PB progenitors were similar after mobilization with either intermediate or intensive chemotherapy. The degree of Ph negativity in the mobilized product correlated with disease stage at the time of mobilization (early chronic phase [ECP] > late CP > accelerated phase). Cytogenetic responses after transplantation with mobilized progenitors obtained after the different regimens were similar. The cytogenetic status of the graft predicted the cytogenetic status of marrow obtained 3 weeks after transplantation whereas cytogenetic responses 3, 6, and 12 months after transplantation correlated with the number of BCR/ABL–negative CD34+HLA-DR−cells, but not the number of Ph-negative metaphases in the graft. In patients with ECP CML, mobilized PB collections yielded significantly more CD34+HLA-DR− cells than from steady state or mobilized BM. CD34+HLA-DR− cells were Ph negative and polyclonal (X-chromosome inactivation) in the majority of ECP CML patients, before and after mobilization and irrespective of the mobilization regimen. Because infusion of large numbers of Ph-negative CD34+HLA-DR− cells predicted superior outcome after transplantation, approaches in which CD34+HLA-DR− cells are selected from mobilized PB may result in longer lasting and clinically significant cytogenetic responses after transplantation. © 1998 by The American Society of Hematology.

Sensitive NOD-scid-IL2γnull (NOG-scid) Assay for Human Precursor B Acute Lymphoblastic Leukemias (ALL).

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4286-4286
Author(s):  
Sebastien Morisot ◽  
Richard Hildreth ◽  
Ian M. Kaplan ◽  
Maryalice Stetler-Stevenson ◽  
Julie A. Taylor ◽  
...  
Keyword(s):  
Cell Lines ◽  
Human Cells ◽  
Scid Mice ◽  
In Vivo Model ◽  
Leukemic Blast ◽  
In Vivo Models ◽  
Post Transplant ◽  
Pediatric All ◽  
Blast Cells

Abstract Results of treatment for childhood ALL have improved considerably over the past few decades, yet still ∼20% of pediatric patients relapse. New in vivo models of human ALL might increase understanding of ALL biology and speed preclinical development of novel treatment regimens. Multiple strains of immunodeficient mice support growth of human ALL cells (Bachmann, Current Drugs Target 2007, review). The recently described highly immunodeficient NOD-scid-IL2γnull (NOG-scid) mouse strain offers a number of advantages over the widely-used NOD-scid strain: NOG-scid mice have a normal lifespan, do not develop spontaneous lymphomas, and require ∼10-fold fewer normal human hematopoietic stem-progenitor cells to generate human hematopoiesis (Hiramatsu, Blood 2003; Ishikawa, Blood 2005). In addition, NOG-scid mice support generation of human leukemia from transplanted human acute myeloid leukemia (AML) (Ninomiya, Leukemia 2007). Herein we report a sensitive in vivo model using transplant of human childhood precursor B ALL cells into sublethally irradiated NOG-scid mice. Transplanted mice developed fatal leukemia 4–5 weeks after intravenous injection of 5x104 REH or KOPN8 cells (established precursor B ALL cell lines derived from pediatric ALL patients). At necropsy, the mice had massive splenomegaly and hyperplastic bone marrow. Blood, spleen, and marrow contained abundant human cells with immunophenotype matching the transplanted ALL cell line. We went on to similarly transplant primary leukemic blast cells from pediatric ALL patients. In 3 of 5 tested primary ALL cases, fatal human leukemias developed in the NOG-scid mice. In titrations of 103-2.5x106 transplanted ALL cells, time to clinical leukemia was dose-dependent, and 1000 primary human cells was sufficient to initiate leukemia development. In addition, we detected human leukemic blast cells by flow cytometric immunophenotyping in the blood of transplanted NOG-scid mice as early as 10 days post-transplant, enabling objective leukemia diagnosis ∼4 weeks prior to clinical signs. CONCLUSIONS: NOG-scid mice supported the generation of human precursor B ALL from cell lines and primary ALL cases, objectively detectable as early as 10 days post-transplant. Our dose titration results suggest that this model detects a high frequency of ALL-initiating cells. This in vivo model may provide a powerful assay both for fundamental questions regarding the biology of leukemia stem cells and for preclinical studies of novel anti-neoplastic agents and regimens.

Fas-Mediated Modulation of Bcr/Abl in Chronic Myelogenous Leukemia Results in Differential Effects on Apoptosis

Blood ◽  
1998 ◽  
Vol 92 (3) ◽  
pp. 981-989 ◽  
Author(s):  
Carmine Selleri ◽  
Jaroslaw P. Maciejewski ◽  
Fabrizio Pane ◽  
Luigia Luciano ◽  
Anna Maria Raiola ◽  
...  
Keyword(s):  
Chronic Myelogenous Leukemia ◽  
Chronic Phase ◽  
Poor Response ◽  
Inhibitory Response ◽  
Myelogenous Leukemia ◽  
Poor Responders ◽  
Cd34 Cells ◽  
In Cells

Fas-R is expressed constitutively in CD34+ cells of patients with chronic myelogenous leukemia (CML); Fas-R triggering results in decreased proliferation rate due to apoptosis of clonogenic cells. We have already shown that α-interferon (IFN-α) enhances Fas-R expression on CML progenitor cells, thus increasing their sensitivity to Fas-R agonists. Although it appears that IFN-α can prime CML cells for the effects of Fas, the response to IFN-α in vivo is not a constant feature in CML patients. We studied the mechanisms of Fas-mediated apoptosis in 11 patients suffering from CML in chronic phase and tried to see whether there was a correlation between in vitro inducibility of apoptosis in CD34+ CML cells after Fas-R triggering and the clinical response to IFN-α. After priming with IFN-α, Fas triggering resulted in in vitro suppression of hematopoietic cell growth in seven of eight patients who had optimal hematologic response to IFN-α; in the same conditions, no inhibitory response to Fas-R agonist was observed in cells from three of three patients who proved to be poor responders to IFN-α. In responders to IFN-α, Fas-R agonist induced dose-dependent apoptosis of CD34+ cells; this effect was associated with a decrease in the bcr/abl protein level. In cells derived from patients with a poor response to IFN-α, the rate of apoptosis in culture remained unchanged in the presence of Fas-R agonist and nobcr/abl downmodulation was observed. Finally, we measuredbcr/abl mRNA by quantitative reverse-transcriptase polymerase chain reaction (RT-PCR) and found that decreased bcr/ablprotein after Fas triggering was not associated with decreased amounts of specific mRNA, a finding which is consistent with a posttranscriptional regulation of the bcr/abl protein expression. It appears that Fas-mediated downmodulation of p210bcr/abl restores susceptibility to apoptosis of CML cells; in addition, in vitro studies on CML cells may predict response to IFN-α treatment. © 1998 by The American Society of Hematology.

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