Donor stromal cells from human blood engraft in NOD/SCID mice

Blood ◽  
2000 ◽  
Vol 96 (12) ◽  
pp. 3971-3978 ◽  
Author(s):  
Silvia-Renate Goan ◽  
Ilse Junghahn ◽  
Manuela Wissler ◽  
Michael Becker ◽  
Jutta Aumann ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Stromal Cells ◽  
Peripheral Blood ◽  
Blood Cells ◽  
Immunohistochemical Staining ◽  
Scid Mice ◽  
Rt Pcr ◽  
Specific Antibodies ◽  
Human Specific

Little is known about the presence, frequency, and in vivo proliferative potential of stromal cells within blood-derived hematopoietic transplants. In this study, nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice were injected with human CD34+ peripheral blood cells (PBCs) or cord blood cells (CBCs, either enriched for CD34 or density-gradient separated mononuclear cells). Flow cytometric analysis 5 to 11 weeks after transplantation revealed the presence of a human lymphomyeloid hematopoiesis within the murine bone marrow. Immunohistochemical staining of bone marrow cell suspensions using human-specific antibodies showed human cells staining positive for human fibroblast markers, human von Willebrand factor (vWF) and human KDR (vascular endothelial growth factor receptor-2) in mice transplanted with CD34+ PBCs or CBCs, with mean frequencies between 0.6% and 2.4%. In stromal layers of bone marrow cultures established from the mice, immunohistochemical staining using human-specific antibodies revealed flattened reticular cells or spindle-shaped cells staining positive with human-specific antifibroblast antibodies (mean frequency, 2.2%). Cell populations of more rounded cells stained positive with human-specific antibodies recognizing CD34 (1.5%), vWF (2.2%), and KDR (1.6%). Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis and subsequent complementary DNA sequencing detected transcripts of human KDR (endothelial specific) and human proline hydroxylase-α (fibroblast specific) within the bone marrow and spleen of transplanted mice. Analysis of nontransplanted control mice yielded negative results in immunocytochemistry and RT-PCR. Cells expressing endothelial and fibroblast markers were also detected in the grafts before transplantation, and their numbers increased up to 3 log in vivo after transplantation. These results indicate that stromal progenitor cells are present in human cytokine-mobilized peripheral blood or cord blood that engraft in NOD/SCID mice.

Donor stromal cells from human blood engraft in NOD/SCID mice

Blood ◽  
2000 ◽  
Vol 96 (12) ◽  
pp. 3971-3978 ◽  
Author(s):  
Silvia-Renate Goan ◽  
Ilse Junghahn ◽  
Manuela Wissler ◽  
Michael Becker ◽  
Jutta Aumann ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Stromal Cells ◽  
Peripheral Blood ◽  
Blood Cells ◽  
Immunohistochemical Staining ◽  
Scid Mice ◽  
Rt Pcr ◽  
Specific Antibodies ◽  
Human Specific

Abstract Little is known about the presence, frequency, and in vivo proliferative potential of stromal cells within blood-derived hematopoietic transplants. In this study, nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice were injected with human CD34+ peripheral blood cells (PBCs) or cord blood cells (CBCs, either enriched for CD34 or density-gradient separated mononuclear cells). Flow cytometric analysis 5 to 11 weeks after transplantation revealed the presence of a human lymphomyeloid hematopoiesis within the murine bone marrow. Immunohistochemical staining of bone marrow cell suspensions using human-specific antibodies showed human cells staining positive for human fibroblast markers, human von Willebrand factor (vWF) and human KDR (vascular endothelial growth factor receptor-2) in mice transplanted with CD34+ PBCs or CBCs, with mean frequencies between 0.6% and 2.4%. In stromal layers of bone marrow cultures established from the mice, immunohistochemical staining using human-specific antibodies revealed flattened reticular cells or spindle-shaped cells staining positive with human-specific antifibroblast antibodies (mean frequency, 2.2%). Cell populations of more rounded cells stained positive with human-specific antibodies recognizing CD34 (1.5%), vWF (2.2%), and KDR (1.6%). Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis and subsequent complementary DNA sequencing detected transcripts of human KDR (endothelial specific) and human proline hydroxylase-α (fibroblast specific) within the bone marrow and spleen of transplanted mice. Analysis of nontransplanted control mice yielded negative results in immunocytochemistry and RT-PCR. Cells expressing endothelial and fibroblast markers were also detected in the grafts before transplantation, and their numbers increased up to 3 log in vivo after transplantation. These results indicate that stromal progenitor cells are present in human cytokine-mobilized peripheral blood or cord blood that engraft in NOD/SCID mice.

Long-term multilineage expression in peripheral blood from a Moloney murine leukemia virus vector after serial transplantation of transduced bone marrow cells

Blood ◽  
2000 ◽  
Vol 95 (3) ◽  
pp. 829-836 ◽  
Author(s):  
Timothy W. Austin ◽  
Suzan Salimi ◽  
Gabor Veres ◽  
Franck Morel ◽  
Heini Ilves ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Peripheral Blood ◽  
Blood Cells ◽  
Transgene Expression ◽  
Bone Marrow Cells ◽  
Leukemia Virus ◽  
Moloney Murine Leukemia Virus ◽  
Marrow Cells

Using a mouse bone marrow transplantation model, the authors evaluated a Moloney murine leukemia virus (MMLV)-based vector encoding 2 anti-human immunodeficiency virus genes for long-term expression in blood cells. The vector also encoded the human nerve growth factor receptor (NGFR) to serve as a cell-surface marker for in vivo tracking of transduced cells. NGFR+ cells were detected in blood leukocytes of all mice (n=16; range 16%-45%) 4 to 5 weeks after transplantation and were repeatedly detected in blood erythrocytes, platelets, monocytes, granulocytes, T cells, and B cells of all mice for up to 8 months. Transgene expression in individual mice was not blocked in the various cell lineages of the peripheral blood and spleen, in several stages of T-cell maturation in the thymus, or in the Lin−/loSca-1+ and c-kit+Sca-1+ subsets of bone marrow cells highly enriched for long-term multilineage-reconstituting activity. Serial transplantation of purified NGFR+c-kit+Sca-1+bone marrow cells resulted in the reconstitution of multilineage hematopoiesis by donor type NGFR+ cells in all engrafted mice. The authors concluded that MMLV-based vectors were capable of efficient and sustained transgene expression in multiple lineages of peripheral blood cells and hematopoietic organs and in hematopoietic stem cell (HSC) populations. Differentiation of engrafting HSC to peripheral blood cells is not necessarily associated with dramatic suppression of retroviral gene expression. In light of earlier studies showing that vector elements other than the long-terminal repeat enhancer, promoter, and primer binding site can have an impact on long-term transgene expression, these findings accentuate the importance of empirically testing retroviral vectors to determine lasting in vivo expression.

scholarly journals Severe Combined Immunodeficiency Mice Engrafted With Human T Cells, B Cells, and Myeloid Cells After Transplantation With Human Fetal Bone Marrow or Liver Cells and Implanted With Human Fetal Thymus: A Model for Studying Human Gene Therapy

Blood ◽  
1997 ◽  
Vol 89 (5) ◽  
pp. 1800-1810 ◽  
Author(s):  
Sergey Yurasov ◽  
Tobias R. Kollmann ◽  
Ana Kim ◽  
Christina A. Raker ◽  
Moshe Hachamovitch ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Bone Marrow ◽  
T Cells ◽  
Peripheral Blood ◽  
Severe Combined Immunodeficiency ◽  
Precursor Cells ◽  
Scid Mice ◽  
Combined Immunodeficiency ◽  
Human T Cells

To develop an in vivo model wherein human hematopoiesis occurs, we transplanted severe combined immunodeficiency (SCID) mice with either human fetal bone marrow (HFBM) or human fetal liver (HFL). After transplantation of SCID mice with cultured HFBM (BM-SCID-hu mice) or HFL cells (Liv-SCID-hu mice), significant engraftment of the mouse bone marrow (BM) and population of the peripheral blood with human leukocytes was detected. Human colony-forming unit–granulocyte macrophage and burst forming unit-erythroid were detected in the BM of the BM-SCID-hu and Liv-SCID-hu mice up to 8 months after transplantation. When the HFBM or HFL cells were transduced with a retroviral vector before transplantation, integrated retroviral sequences were detected in human precursor cells present in the SCID mouse BM and in leukocytes circulating in the peripheral blood (PB) up to 7 months after transplantation. The PB of the BM-SCID-hu mice also became populated with human T cells after implantation with human thymic tissue, which provided a human microenvironment wherein human pre-T cells from the BM could mature. When the HFBM was retrovirally transduced before transplantation, integrated retrovirus was detected in sorted CD4+CD8+ double positive and CD4+ single positive cells from the thymic implant and CD4+ cells from the PB. Taken together, these data indicated that the BM of our BM-SCID-hu and Liv-SCID-hu mice became engrafted with retrovirally transduced human hematopoietic precursors that undergo the normal human hematopoietic program and populate the mouse PB with human cells containing integrated retroviral sequences. In addition to being a model for studying in vivo human hematopoiesis, these mice should also prove to be a useful model for investigating in vivo gene therapy using human stem/precursor cells.

scholarly journals Evaluation of the genotoxic potential of Austroplenckia populnea (Reiss) Lundell chloroform fraction from barkwood extract in rodent cells in vivo

2009 ◽  
Vol 69 (4) ◽  
pp. 1141-1147 ◽  
Author(s):  
JC. Ribeiro ◽  
SF. Andrade ◽  
JK. Bastos ◽  
EL. Maistro
Keyword(s):  
Bone Marrow ◽  
Peripheral Blood ◽  
Chromosome Aberrations ◽  
Blood Cells ◽  
Bone Marrow Cells ◽  
Chloroform Fraction ◽  
Peripheral Blood Cells ◽  
Swiss Mice ◽  
Marrow Cells

The genotoxic effect of the Austroplenckia populnea chloroform fraction from barkwood extract was tested in vivo on peripheral blood cells of Swiss mice with the comet assay (SCGE), and the clastogenic effect was investigated on peripheral blood cells of Swiss mice and bone marrow cells of Wistar rats, with the micronucleus and chromosome aberrations tests. The animals were treated by gavage with 3 concentrations of the extract: 300, 600 and 900 mg.kg-1. Peripheral blood cells of Swiss mice were collected 4 and 24 hours after the treatment to the SCGE assay and 48 and 72 hours to the micronucleus test. Bone marrow cells of Wistar rats were collected 24 hours after the treatment to the micronucleus and chromosome aberration tests. The results showed that the A. populnea chloroform fraction induced an increase in the average number of DNA damage in peripheral blood cells at the three concentrations tested, but this increase was not statistically significant. In the micronucleus and chromosome aberrations test, no significant increase was observed in the mean number of micronucleated polychromatic erythrocytes (MNPCE) of Swiss mice or MNPCE or chromosome aberrations for the rat bone marrow cells, for any of the tested doses. Our findings enable us to conclude that by the comet assay, A. populnea chloroform fraction from barkwood extract showed no genotoxic effects, and by the micronucleus and chromosome aberration tests, the extract fraction showed no clastogenic/aneugenic effects on the rodent cells tested.

A SCID-hu In Vivo Mouse Model of Human Primary Mantle Cell Lymphoma.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2337-2337
Author(s):  
Michael Wang ◽  
Yuankai Shi ◽  
Liang Zhang ◽  
Xiaohong Han ◽  
Jing Yang ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Gastrointestinal Tract ◽  
Immunohistochemical Staining ◽  
Cell Lymphoma ◽  
Scid Mice ◽  
Mouse Serum ◽  
Fetal Bone ◽  
Preclinical Evaluation ◽  
Mantle Cell

Abstract Introduction: Mantle cell lymphoma (MCL) has a poor outcome and is a therapeutic challenge. Preclinical evaluation of investigational agents for MCL has been limited by lack of suitable animal models that mimic the natural history of human MCL and provide the microenvironment in which MCL cells thrive. Since MCL usually involves the bone marrow, we developed an in vivo mouse model for primary human MCL cells in severe combined immunodeficient mice (SCID-hu), which have been implanted with human fetal bone. Materials and Methods: Human primary MCL cells were obtained and isolated from spleen, lymph nodes, bone marrow aspirates, or peripheral blood of six different MCL patients. Purified patient primary MCL cells were directly inoculated into human fetal bone chip or injected into mouse tail vein. Immunohistochemical staining with anti-human CD20 or cyclin D1 antibodies and detection of circulating human beta 2-microglobulin (B2M) in mouse serum were used to monitor the engraftment, growth, and immigration of human primary MCL cells in SCID-hu mice. Results: A total of 30 SCID-hu mice and 5 SCID mice were used. Twenty of SCID-hu mice received inoculation of 0.5 – 5 × 106 of patient primary MCL cells (2–5 SCID-hu mice/patient sample) into human fetal bone chips implanted in mice subcutaneously. Five of SCID-hu mice and 5 of SCID mice (without human fetal hone chips) were injected intravenously with 5 × 106 of patient MCL cells. The same number of cells were injected into human bone chips in 5 SCID-hu mice with equal volume of PBS as controls. Successful primary MCL cell engraftment was observed in 15 out of 20 SCID-hu mice after injection of these cells into human fetal bones. But only one out of 5 SCID-hu mice had successful engraftment after the intravenous injection of primary MCL cells into mouse tail vein. Importantly, none of SCID mice had successful engraftment after intravenous injection of 5 × 106 of primary MCL cells. These data indicated that human fetal bone provides a critical microenvironment for the survival and growth of primary MCL cells. Increasing levels of circulating human B2M in mouse serum were found after successful engraftment and growth of human primary MCL cells in SCID-hu mice. Immunohistochemical staining with anti-human CD20 and cyclin D1 antibodies confirmed that, similar to the human disease, primary MCL cells homed to mouse lymph nodes, spleen, bone marrow, and gastrointestinal tract but not to mouse liver. Treatment of MCL-bearing SCID-hu mice with atiprimod suppressed B2M secreted by functioning human MCL cells and induced tumor regression. Conclusion: Human primary MCL cells from patient were able to successfully engraft in SCID-hu mice, and mimiced the natural organ involvement of human disease homing to mouse lymph node, spleen, bone marrow, and gastrointestinal tract but not to liver. This in vivo model mimiced the natural biological features of human MCL and is therefore useful for preclinical evaluation of new therapeutic agents.

A Novel FOXP1-PDGFRA Fusion Gene in A Case of Chronic Eosinophilic Leukemia.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2830-2830
Author(s):  
Yuka Sugimoto ◽  
Akiko Sada ◽  
Fumihiko Monma ◽  
Kohshi Ohishi ◽  
Masahiro Masuya ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Peripheral Blood ◽  
Blood Cells ◽  
Genomic Dna ◽  
Low Dose ◽  
Fusion Gene ◽  
Fish Analysis ◽  
Fusion Partner ◽  
Rt Pcr ◽  
Total Rna

Abstract Abstract 2830 Introduction Myeloid and lymphoid neoplasms with eosinophilia and abnormalities of PDGFRA, PDGFRB, or FGFR1 is a new major category in the 2008 WHO classification of myeloid malignancies. FIP1L1-PDGFRA fusion gene is currently the most common abnormality in this category, but there are some other fusion genes incorporating part of PDGFRA. In a case of myeloproliferative neoplasms (MPN) with eosinophilia and hepatosplenomegaly, karyotype by G-banding and fluorescence in situ hybridization (FISH) for 4q12 rearrangements indicated a PDGFRA rearrangement other than FIP1L1-PDGFRA, and a novel FOXP1-PDGFRA fusion gene was identified. Case presentation A 44-year-old male visited a clinic because of wet cough for one year. His peripheral blood showed leukocytosis of 43.15 × 109 /L with eosinophilia up to 57.5%, mild erythrocytosis (Hb 17.3 g/dL), and thrombocytopenia of 86 × 109 /L. CT scan of the abdomen revealed hepatosplenomegaly. He was referred to our hospital and received oral PSL (1 mg/kg) first, because pulmonary eosinophilic infiltration was suspected by follow-up CT findings. Pulmonary infiltration and his cough disappeared rapidly in a week, but his leukocytosis with eosinophilia was exacerbated again with PSL tapering. His bone marrow at the time of admission disclosed hypercellular marrow with myeloid hyperplasia and eosinophilia, of which karyotype was 46, XY, t(3:4)(p13;q12), inv(9)(p12q13) in all of 20 metaphases. FISH analysis with tricolor 4q12 rearrangement probe set indicated that PDGFRA was disrupted in 97.3% of his peripheral blood cells. These cytogenetic abnormalities of his bone marrow cells suggested involvement of PDGFRA fusion gene except for FIP1L1-PDGFRA and did not disappear after steroid administration for 2 weeks. After low-dose of imatinib (100 mg/day) was started, he achieved a hematological response within 5 days, and PSL could be gradually tapered off. 3 months after therapy, he obtained complete cytogenetic response (CCyR). He has been in CCyR and free of symptoms for more than 6 months with only low-dose imatinib. Methods and Results Genomic DNA and total RNA were isolated from white blood cells in his peripheral blood at diagnosis. Complementary DNA was synthesized from total RNA. FIP1L1-PDGFRA fusion transcript was proved to be negative by RT-PCR. Molecular cloning with 5′-RACE-PCR revealed a novel mRNA in-frame fusion between exon 23 of FOXP1 and a truncated PDGFRA exon12. Reciprocal PDGFRA-FOXP1 transcripts were confirmed by RT-PCR analysis and FOXP1-PDGFRA genomic DNA sequence was determined with genomic PCR. As in the case with FIP1L1-PDGFRA, the breakpoint of PDGFRA in FOXP1-PDGFRA was located between the two tryptophan (W) residues of the putative WW-domain. Meanwhile, the other breakpoint was near inverted repeat in intron 23 of FOXP1, which is presumed to be very fragile site. By FISH analysis after magnetic cell sorting with MicroBeads, the 4q12 abnormality attributed to FOXP1-PDGFRA fusion gene was detected in granulocytes, but not in CD19-positive B or CD3-positive T cells. Discussion In a case with chronic eosinophilia harboring 46, XY, t(3:4)(p13;q12), inv(9)(p12q13), novel FOXP1-PDGFRA fusion gene was identified. Similar karyotypic abnormality harboring t(3:4)(p13;q12) was reported in a case of MPN with chronic eosinophilia, but responsible fusion gene was not identified (Myint H, et al. Br J Haematol. 1995). FOXP1 is a transcription factor which is implicated in a variety of cellular processes and has a role in immune regulation and carcinogenesis (Wlodarska I, et al. Leukemia. 2005). As a fusion partner of FOXP1, PAX5 and ABL1 are reported in cases with acute lymphoblastic leukemia. Thus, this is a first report showing that FOXP1-PDGFRA fusion gene is involved in hematologic malignancy. It is likely that FOXP1-PDGFRA is constitutively activated tyrosine kinase, which does not depend on dimerization but on the disruption of an autoinhibitory juxtamembrane domain encoded by exon 12 of PDGFRA from its structure. Eosinophilia responded well to low dose of imatinib as observed in CEL with FIP1L1-PDGFRA. Conclusion FOXP1-PDGFRA was identified in CEL for the first time. This is the eighth reported fusion gene associated with PDGFRA in CEL so far. Our patient with FOXP1-PDGFRA promptly responded to low-dose of imatinib as same as other cases with PDGFRA abnormalities. Further investigation is still in progress. Disclosures: No relevant conflicts of interest to declare.

Influence of Different Genetic Alterations On the Engraftment Capacity and Serial Transplantation Efficiency of AML Patient-Derived Bone Marrow and Peripheral Blood Cells in NSG Mice

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 3511-3511
Author(s):  
Julia Schüler ◽  
Peter Haas ◽  
Kerstin Klingner ◽  
Björn W. Hackanson ◽  
Heinz-Herbert Fiebig ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Overall Survival ◽  
Peripheral Blood ◽  
Blood Cells ◽  
Bone Marrow Cells ◽  
Growth Behavior ◽  
Peripheral Blood Cells ◽  
Nsg Mice ◽  
Marrow Cells

Abstract Abstract 3511 Introduction: In order to allow a better understanding of acute myeloid leukemia (AML) and develop more promising therapeutic strategies the establishment of functional and reproducible in vivo models is widely pursued. Of available model systems, xenografts in immunodeficient mice reproduce the clinical situation best. Here, we performed extensive analysis of AML engraftment in NOD/SCID-IL2-receptor-gamma-chain−/− (NSG) mice comparing tail vein versus intratibial injection and growth behavior of AML patient-derived bone marrow versus peripheral blood cells. Furthermore, tumor growth characteristics in the murine host were correlated with the disease stage and the molecular risk factor profile of the individual donors. Methods: Bone marrow and peripheral blood cells from 17 AML patients were injected intratibially into NSG mice (n=4–8/patient, 82 mice in total). As controls, 14 mice received bone marrow from three different donors and 5 mice were mock-injected. Tumor growth was monitored via a) determination of overall survival, b) fluorescence-based in vivo imaging (IVI, Kodak FX, Alexa750 labeled anti-human CD45 or CD33 and c) confirmation of IVI data by histological and immunohistochemical examination of bone marrow and spleen. When highly positive IVI signals and/or the overall condition of individual mice indicated enlarged tumor burden, the respective animals were sacrificed and the human AML cells transferred to another animal. In parallel the engraftment pattern of AML cells 2–4 weeks posttransplant was correlated with clinical disease activity, application route and origin of the particular tumor cells. Results: Patients included in the present study represent multiple different French-American-British (FAB) subtypes, various karyotypes and molecular features in terms of the mutational status of NPM1 and FLT3. All patient-derived specimens were capable of recapitulating the disease in NSG mice at 4–6 weeks after transplantation. Over a period of 13 months 12 out of 17 xenografts could be passaged once and 9 at least twice. Up to six passages were performed for an individual AML xenograft. In contrast, engraftment of healthy donor bone marrow cells could be determined merely until day 56 after implantation. The human bone marrow cells of the healthy donors did not engraft in serial passages. Mean survival time of AML bearing animals ranged between 21 and 82 days for a respective xenograft. No differences could be determined between engraftment capacities of peripheral blood or bone marrow cells of one patient. Neither karyotype, FAB classification nor leucocyte count or the percentage of monomorphic blasts in the bone marrow seemed to have an impact on engraftment capacity in the murine organism. However, mice bearing AML xenografts with mutations in FLT3 as well as in NPM1 showed particular short overall survival times and high tumor cell engraftment determined by IVI. This phenomenon became more obvious along the different passages. The intratibial approach proved to be superior in comparison to the intravenous application as cells of an individual patient engrafted faster when injected directly into the bone marrow microenvironment. Determination or tumor load via IVI permits to closely monitor not only the growth behavior but also the homing characteristics of the human cells over time. The positive IVI signals in bone marrow and spleen could be confirmed by histological examination as well as by immunohistochemistry specific for human CD45 and CD33. Conclusions: Our xenografts show a close resemblance to the AML-disease regarding the level of dissemination and organ involvement. Collection of whole-body IVI data proved to be a time- and animal-saving analysis that allows to closely monitor AML growth. As AML is characterized by an increasing number of molecular subtypes with completely different therapeutic options it seems to be extremely worthwhile to develop patient derived xenograft models representing as many AML subtypes as possible. Our results suggest that this model reflects the heterogeneity and important clinical characteristics of the disease, and thus may serve as a tool for preclinical drug testing and investigation of the pathophysiology of AML. Disclosures: No relevant conflicts of interest to declare.

The Ryk Receptor Regulates Hematopoietic Stem and Progenitor Cell Proliferation and Their Sensitivity To Myeloablative Agents

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 796-796
Author(s):  
Benjamin Povinelli ◽  
Michael Nemeth
Keyword(s):  
Bone Marrow ◽  
Peripheral Blood ◽  
Blood Cells ◽  
Molecular Mechanisms ◽  
Bone Marrow Cells ◽  
Conflicts Of Interest ◽  
Peripheral Blood Cells ◽  
Hematopoietic Stem ◽  
Marrow Cells

Abstract The molecular mechanisms that control the balance between quiescence and proliferation of hematopoietic stem and progenitor cells (HSPCs) are critical for maintaining life-long hematopoiesis. In a recent study (Povinelli, et al. Stem Cells, In Press, 2013) we demonstrated that the Wnt5a ligand inhibits HSPC proliferation through a functional interaction with a non-canonical Wnt ligand receptor termed Related to Receptor Tyrosine Kinase (Ryk). Expression of Ryk on HSPCs in vivo was associated with a decreased rate of proliferation. Following treatment with fluorouracil (5-FU), the percentage of Ryk+ HSPCs increased at the expense of Ryk-/low HSPCs. Based on these data, we hypothesized that one function of the Ryk receptor is to protect HSPCs from the effects of myeloablative agents. To test this hypothesis, we injected 6-8 week old C57BL/6 mice with 150 mg/kg of 5-FU and analyzed bone marrow 48 hours later for the presence of apoptotic HSPCs, defined as lineage negative (Lin-), Sca-1+, CD48- cells positive for active caspase-3. There was a 2.5-fold decrease in the percentage of apoptotic Ryk+ HSPCs (12.9 ± 1.7%) compared to Ryk-/low HSPCs (32.4 ± 5.3%, p < 0.001, n = 3). To test whether this effect was limited to 5-FU, we performed a similar study in which we irradiated C57BL/6 mice with 3 cGy of total body irradiation (TBI) and analyzed bone marrow 72 hours later for apoptotic HSPCs (for this experiment, defined by a Lin-, c-kit+, Sca-1+, CD150+, CD48- immunophenotype or LSK, SLAM). Comparable to the effects of 5-FU, there was a significant 3.0-fold reduction in the percentage of apoptotic Ryk+ HSPCs (3.1 ± 0.2%) compared to Ryk-/low HSPCs (9.2 ± 1.5%, p < 0. 001, n = 3) in mice receiving 3 cGy TBI. These results demonstrated an association between Ryk expression and survival of HSPCs following myeloablative injury. To determine whether in vivo targeting of the Ryk receptor would increase the sensitivity of HSPCs to myeloablative injury, we utilized a neutralizing rabbit anti-Ryk antibody (α-Ryk). We injected C57BL/6 mice with 5 mg/kg α-Ryk or rabbit IgG isotype for 2 consecutive days. Twenty-four hours after the second dose, we determined the frequency and cell cycle status of LSK SLAM cells. Treatment with α-Ryk significantly increased the percentage of LSK SLAM cells in the S/G2/M phases compared to control (α-Ryk: 17.8 ± 2.2%; isotype IgG: 11.6 ± 2.7%, p < 0.05, n = 3). This was associated with a decrease in the percentage of LSK, SLAM cells in G1 following treatment with α-Ryk (α-Ryk: 40.5 ± 3.2%, isotype IgG: 51.3 ± 2.2; p < 0.01, n = 3). The percentage of G0 LSK SLAM cells was unchanged (α-Ryk: 37.9 ± 2.6, isotype IgG: 35.7 ± 3.1% n = 3) indicating that inhibiting Ryk promoted the exit of LSK SLAM cells from G1. Treatment with α-Ryk also increased the percentage of whole bone marrow cells expressing the LSK SLAM phenotype by 1.4-fold compared to controls (p < 0.05, n = 3). To determine if α-Ryk treatment altered HSPC function, we transplanted whole bone marrow cells from C57BL/6 mice treated with two days of α-Ryk or isotype IgG at a 1:1 ratio with whole bone marrow from untreated Ubc-GFP transgenic mice into lethally irradiated B6.SJL mice. Four weeks after transplant, we analyzed peripheral blood cells for the percentage of CD45.2+ GFP- cells. There was no difference in engraftment by transplanted bone marrow cells from mice treated with α-Ryk or isotype IgG (α-Ryk: 61.6 ± 6.1% n = 4, isotype IgG: 52.8 ± 13.6%, n = 5), indicating that the neutralizing antibody does not inhibit short-term HSPC function on its own. We then tested whether blocking Ryk function resulted in greater sensitivity of HSPCs to 5-FU. We treated B6.SJL mice with 5 mg/kg α-Ryk or isotype IgG for 2 consecutive days, followed by 150 mg/kg of 5-FU. Forty-eight hours after 5-FU treatment, we transplanted 2x106 C57BL/6 whole bone marrow cells into treated B6.SJL mice without additional conditioning. Four weeks after transplant, we determined the percentage of donor-derived CD45.2+ peripheral blood cells. Treatment of recipient mice with α-Ryk prior to 5-FU treatment resulted in increased engraftment of donor bone marrow by 3.6-fold compared to isotype (p < 0.05, n = 5), suggesting that inhibition of Ryk resulted in increased elimination of host HSPCs by 5-FU. Collectively, these data suggest a model in which inhibition of the Ryk receptor results in increased proliferation of HSPCs, rendering them more sensitive to the effects of myeloablative agents such as chemotherapy or TBI. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Preclinical Mechanistic Studies Investigating Neutrophil and Lymphoid Cell Depletion By IMGN529, a CD37-Targeting Antibody-Drug Conjugate (ADC)

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3119-3119 ◽  
Author(s):  
Jutta Deckert ◽  
Jose F. Ponte ◽  
Jennifer A. Coccia ◽  
Leanne Lanieri ◽  
Sharon Chicklas ◽  
...  
Keyword(s):  
Bone Marrow ◽  
B Cell ◽  
Peripheral Blood ◽  
Blood Cells ◽  
Peripheral Blood Cells ◽  
Employment Equity ◽  
Normal Human ◽  
Equity Ownership

Abstract CD37 is a surface antigen widely expressed on malignant B cells in non-Hodgkin lymphoma (NHL) and chronic lymphocytic leukemia (CLL). In normal tissues, CD37 expression is restricted to lymphoid tissues and blood cells, with high levels of expression on B lymphocytes and low levels on non-B lymphoid and myeloid cells. IMGN529 is a CD37-targeting ADC currently in a Phase I clinical study in adult patients with relapsed or refractory NHL (NCT01534715). This ADC uniquely combines the intrinsic pro-apoptotic and immune effector activities of its anti-CD37 antibody component with the potent cytotoxic mechanism provided by targeted delivery of its maytansinoid payload, DM1. In the Phase I study, IMGN529 has demonstrated early evidence of clinical activity. A reduction in lymphocyte counts was also observed in the majority of patients after dosing, consistent with the proposed mechanism of action of a CD37-targeted therapy. However, in the initial dose-escalation phase, some patients experienced transient, early-onset neutropenia. To investigate the potential mechanisms of this transient neutropenia observed in patients, different pre-clinical models were considered and utilized to recapitulate clinical findings. In vitro studies with peripheral blood cells from normal human donors demonstrated that incubation with IMGN529 for 1 hour or 24 hours resulted in significant B-cell depletion with no apparent neutrophil depletion detected, similar to observations after rituximab treatment. In contrast, alemtuzumab treatment in vitro resulted in both B-cell and neutrophil depletion. This is consistent with the high level of CD37 expression on target B cells and the relatively low CD37 expression level on other blood cells. Analysis of cytokine release by normal human donor peripheral blood cells incubated with IMGN529 revealed increased levels of IL-8, CCL2 (MCP-1) and CCL4 (MIP-1β), but not IL-6 or TNF, to a similar extent as rituximab but less pronounced than alemtuzumab. An anti-murine CD37 antibody was identified to enable in vivo studies in a murine model and characterize CD37 expression on murine blood cells. Similar to the expression profile of CD37 in human peripheral blood cells, CD37 expression on murine peripheral blood cells was highest in B cells, with much lower expression seen on T cells and granulocytes. In vivo activity of the anti-muCD37 antibody and the corresponding ADC, with the same SMCC-DM1 linker-payload combination as IMGN529, was evaluated to discern antibody and payload-mediated events in comparison to the classic cytotoxic cyclophosphamide (CPA). Treatment of C57/B6 mice with 1-10 mg/kg of anti-muCD37 antibody or anti-muCD37 ADC resulted in a significant decrease in absolute lymphocyte counts (ALC) lasting greater than 7 days and a transient decrease in absolute neutrophil counts (ANC) lasting 1-2 days. A non-targeted control SMCC-DM1 ADC had no effect on ALC or ANC counts, suggesting the decrease is a CD37-mediated effect. In contrast, treatment with CPA resulted in an ALC decrease with similar kinetics but a more pronounced ANC decline. No impact on bone marrow lymphocyte, myeloid or erythroid precursor cell counts was observed in response to the anti-muCD37 antibody or anti-muCD37 ADC, whereas CPA treatment caused reduced cellularity with a decrease in the percentage of mature myeloid precursors and neutrophils in bone marrow. Elevated levels of CCL2 and CCL4 chemokines were detected in mouse plasma after anti-muCD37 ADC treatment, which may contribute to a redistribution of circulating neutrophils into peripheral tissues. Studies are currently underway to assess neutrophil distribution in murine tissues post anti-muCD37 ADC treatment. Current preclinical studies provide no clear evidence for direct IMGN529-mediated depletion of normal human neutrophils in the context of B-cell depletion in vitro. In vivo studies with an anti-muCD37 ADC recapitulate transient peripheral lymphopenia and neutropenia with no impact on bone marrow precursors observed, indicative of a different mechanism than classic chemotherapy-induced bone marrow myelosuppression. These preliminary results suggest a role for chemokine-mediated neutrophil redistribution following CD37 engagement, which is the subject of further studies. Disclosures Deckert: ImmunoGen, Inc.: Employment, Equity Ownership. Ponte:ImmunoGen, Inc.: Employment, Equity Ownership. Coccia:ImmunoGen, Inc.: Employment, Equity Ownership. Lanieri:ImmunoGen, Inc.: Employment, Equity Ownership. Chicklas:ImmunoGen, Inc.: Employment, Equity Ownership. Yi:ImmunoGen, Inc.: Employment, Equity Ownership. Watkins:ImmunoGen, Inc.: Employment, Equity Ownership. Ruiz-Soto:ImmunoGen, Inc.: Employment, Equity Ownership; sanofi: Employment. Romanelli:ImmunoGen, Inc.: Employment, Equity Ownership; sanofi: Employment. Lutz:ImmunoGen, Inc.: Employment, Equity Ownership.

A Murine Model of Human Primary Leukemia for Studying Leukemia-Stromal Interactions and Prediction of Clinical Outcome.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1192-1192
Author(s):  
John Yu ◽  
Li-en Shao ◽  
Chia-lin Huang ◽  
Alice L. Yu
Keyword(s):  
Stem Cells ◽  
Stromal Cells ◽  
Peripheral Blood ◽  
Scid Mice ◽  
Leukemia Cells ◽  
Human Leukemia ◽  
Similar Treatment ◽  
High Level ◽  
Primary Leukemia

Abstract Acute or chronic leukemias resist apoptosis in vitro when co-cultured with marrow stromal cells, suggesting that the growth/survival of leukemia cells relies in part on interactions with stromal cells in the microenvironment. We have recently demonstrated that consistent and high-level engraftment of human primary leukemia obtained from patients can be achieved in NOD/scid mice by preconditioning with either adherent cord blood or marrow mesenchymal stem cells. High success rate of engraftment (84.9 ± 2.9 % leukemia blasts in mouse marrow) was obtained with many lineages of leukemia including acute T- or B-cell lymphoblastic and myeloid leukemia. In general, leukemia blasts were detectable in peripheral blood of mice by week 4–5, leading to fatal outcome by week 6 (42 ± 4 days). Furthermore, cells from the marrow of these preconditioned mice were found to secrete leukemia-promoting activities, suggesting that the mouse marrow had been altered to favor the proliferation/survival of leukemic cells in vivo. We also showed that the human leukemia cells harvested from mice could be serially transferred to other mice for many generations with ~100 fold increase in the number of leukemic and clonogenic cells in mice, while retaining properties similar to primary leukemia samples obtained from patients. Several lines of evidence in our studies including the appearance of leukemia blasts in marrow and blood, the dissemination to other tissues, and gene expression profiling in microarray analysis confirm that this xenograft model recapitulates key features of human leukemia. Furthermore, weekly i.p. injections of NOD/scid mice with vincristine at 0.5 mg/kg for three weeks, starting at second week after inoculation of patients primary leukemia, resulted in a significant delay in the appearance of human leukemia blasts in blood, doubly the length of mouse survival. In addition, pairs of primary leukemia samples collected at diagnosis and at relapse from the same patients were engrafted into NOD/scid mice. The NOD/scid mice transplanted with either samples developed leukemia in mouse peripheral blood at week 4–5 with similar kinetics after inoculation. However, weekly vincristine treatment x 3 of the mice transplanted with diagnosis leukemia samples, prevented the appearance of leukemia blast cells in the circulating peripheral blood for at least 5 weeks. In contrast, similar treatment of mice engrafted with relapse leukemia samples had 50% leukemia blasts in blood at week 5 and subsequently developed fatal leukemia dissemination at week 7. These findings indicate that this robust high level engraftment model of human primary leukemia may be useful in predicting clinical response to chemotherapy. Evidence has further suggested that these human leukemia in NOD/scid mice may be derived from a small subset of immature stem cells in the samples that give rise to leukemia expansion and phenotypic diversity in these mice. Therefore, we had developed a robust and predictive animal model of human primary leukemia, which is valuable for studying leukemia stem cells and for testing or prioritizing new agents/regimens in vivo.

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