Use of Genome-Wide Expression Analysis to Optimize An Ex Vivo clinical Protocol for 16,16-Dimethyl Prostaglandin E2 Enhancement of Umbilical Cord Blood In Hematopoietic Stem Cell Transplantation.

Abstract Abstract 1451 A systematic investigation was performed to optimize the treatment protocol for ex vivo incubation of human hematopoietic stem cells (HSCs) with 16,16-dimethyl prostaglandin E2 (FT1050) prior to transplantation. This protocol is part of an ongoing Phase Ib clinical trial of FT1050-enhanced double cord blood (CB) transplantation after reduced intensity conditioning. FT1050 has been previously shown in vertebrate models to improve the engraftment potential of HSCs from bone marrow (BM) and CB after a brief ex vivo treatment. In these models, treatment of BM or CB with FT1050 was performed for 1 to 2 hours at 4 °C, followed by a wash and subsequent cell infusion into the recipient (North et al. Nature 2007, Hoggatt et al. Blood 2009). Several groups have demonstrated that under these conditions, FT1050-treated cells have an engraftment advantage over vehicle treated cells. The objective of the current investigation was to identify a set of conditions that maximizes the biologic activity of FT1050. Genome-wide expression analysis and cAMP assays were used to optimize the ex vivo FT1050 treatment protocol with respect to concentration, time and temperature. Using this approach, hundreds of up- and down-regulated genes were identified in FT1050-treated CD34+ cells. These signature genes include upregulation of CXCR4, a known mediator of HSC homing via SDF-1a, and CREB, a key gene involved in cAMP signaling. Results from these experiments demonstrated that FT1050 concentrations above 10 μM did not result in increased levels of biologic activity. In terms of duration of incubation, cAMP activity reached maximal levels within 30 minutes of exposure while a 2 hour treatment period was necessary to maximize the changes in gene expression. Finally, the biologic activity of FT1050 was highly sensitive to temperature, with treatment of cells at 37 °C yielding larger changes in cAMP production and gene expression as compared to incubation of cells at 25 °C and 4 °C. The biological effects of FT1050 on subsets of CD34+ cells isolated from CB were also determined. Interestingly, the stem/progenitor subsets of CD34+ cells (Lin-CD34+CD38-CD90+CD45RA-, Lin-CD34+CD38-CD90-CD45RA- and Lin-CD34+) had a greater response to FT1050 relative to the lineage positive cells. The different conditions were also evaluated using CFU-C and 7-AAD assays. No evidence of adverse effects were observed. Based upon these findings, the ongoing clinical trial incorporates the optimized FT1050 ex vivo treatment protocol (10 μM for 120 minutes at 37 °C). Disclosures: Desponts: Fate Therapeutics, Inc.: Employment, Equity Ownership. Robbins:Fate Therapeutics, Inc.: Employment, Equity Ownership. Le:Fate Therapeutics, Inc.: Employment, Equity Ownership. Thies:Fate Therapeutics, Inc.: Employment, Equity Ownership. Mendlein:Fate Therapeutics, Inc.: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Grayson:Fate Therapeutics Inc.: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Multani:Fate Therapeutics, Inc.: Employment, Equity Ownership. Shoemaker:Fate Therapeutics: Employment, Equity Ownership.

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Ex Vivo Modulation of Mobilized Peripheral Blood: Characterization of HSC and T-Cell Responses to Prostaglandin E2

Blood ◽

10.1182/blood.v124.21.1092.1092 ◽

2014 ◽

Vol 124 (21) ◽

pp. 1092-1092 ◽

Cited By ~ 1

Author(s):

David Robbins ◽

Thuy Le ◽

Christopher Troung ◽

Heather Foster ◽

Betsy Rezner ◽

...

Keyword(s):

T Cell ◽

Peripheral Blood ◽

Ex Vivo ◽

Employment Equity ◽

Genome Wide ◽

Cd34 Cells ◽

Equity Ownership ◽

Camp Levels ◽

Genome Wide Expression ◽

Mobilized Peripheral Blood

Abstract 16,16 dimethyl prostaglandin E2 (FT1050) was previously identified to be a critical regulator of hematopoetic stem cell (HSC) homeostasis and we hypothesized that a brief ex vivo modulation could improve patient outcomes in umbilical cord blood (UCB) transplantation by increasing the “effective dose” of HSCs. Using preclinical models, we have demonstrated that pulse treating human HSCs with FT1050 significantly enhances the homing and engraftment of donor cells to the bone marrow niche, in part by upregulating CXCR4. To date, preclinical and clinical translation of this therapeutic paradigm has focused on UCB. In an initial clinical evaluation, ex vivo modulation of UCB with FT1050 (2 hours, on site, just prior to infusion) was found to accelerate neutrophil recovery (median 17.5 vs 21 days, p = 0.045) in adult patients undergoing double UCB transplantation (Cutler, 2013). In this Phase 1b study, we also observed low rates of viral reactivation (17% incidence of CMV viremia vs. 42-67% reported in the literature) and GvHD, suggesting that FT1050 may also be having a therapeutically relevant effect on the T-cell compartment of the treated UCB units. To explore the potential therapeutic application of ex vivo modulation of other allogeneic HSC sources, we conducted a series of in vitro studies characterizing the effect of FT1050 on HSCs and T-cells derived from mobilized peripheral blood (mPB). CD34+ cells isolated from mPB or UCB were treated with 10μM FT1050 for 2 hours at 37ºC. We showed that FT1050 binds to the EP2 and EP4 receptors on the cell surface, activating adenylate cyclase which results in a rapid increase in intracellular cAMP levels. Results of a competitive antibody binding assay demonstrated robust and comparable increases in cAMP levels in CD34+ cells from both UCB and mPB. Genome-wide expression analysis of FT1050 treated CD34+ cells showed a highly similar expression response in cells isolated from mPB and UCB, including a 20-fold increase in the key HSC homing receptor CXCR4. We also observed similar FT1050-dependent increases in the surface CXCR4 protein levels and significant improvements in transwell migration rates to gradients of SDF-1. Genome-wide expression analysis within the T-cell compartments from both UCB and mPB (e.g., CD8, CD4, NK, Tregs) revealed a highly similar set of FT1050 induced genes which are involved in cell cycle (e.g., CCND1, CCNE1), tolerance (e.g., DUSP5, FLT1) and anti-viral response (e.g., CD56, EFNB2). The results of this preclinical characterization study provides the basis upon which to explore the future use of FT1050 modulated mPB in a clinical setting. Disclosures Robbins: Fate Therapeutics: Employment, Equity Ownership. Le:Fate Therapeutics: Employment, Equity Ownership. Troung:Fate Therapeutics: Employment, Equity Ownership. Foster:Fate Therapeutics: Employment, Equity Ownership. Rezner:Fate Therapeutics: Employment, Equity Ownership. Mitchell:Fate Therapeutics: Employment, Equity Ownership. Guerrettaz:Fate Therapeutics: Employment, Equity Ownership. Multani:Fate Therapeutics: Employment, Equity Ownership. Shoemaker:Fate Therapeutics: Employment, Equity Ownership.

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A GATA-2-GPR65 Regulatory Module Controls Hematopoietic Stem Cell Generation

Blood ◽

10.1182/blood.v126.23.1176.1176 ◽

2015 ◽

Vol 126 (23) ◽

pp. 1176-1176

Author(s):

Xin Gao ◽

Tongyu Wu ◽

Jamie Lahvic ◽

Kirby D. Johnson ◽

Erik A. Ranheim ◽

...

Keyword(s):

Ex Vivo ◽

Negative Regulator ◽

Loss Of Function ◽

Rt Pcr ◽

Employment Equity ◽

Advisory Committees ◽

Hematopoietic Stem ◽

Equity Ownership ◽

G Protein Coupled

Abstract The generation of hematopoietic stem cells (HSCs) via endothelial-to-hematopoietic transition within the aorta-gonad-mesonephros (AGM) region of the mammalian embryo is crucial for development of the adult hematopoietic system. Many questions remain unanswered regarding the molecular program in hemogenic endothelium that promotes the budding of hematopoietic cell clusters containing HSCs. We demonstrated that a deletion of a Gata2 cis-element reduced GATA-2 levels in the AGM and abrogated the capacity of hemogenic endothelium to generate HSCs. Consistent with the defective HSC generator, the mutant fetal livers were deficient in hematopoietic stem and progenitor cells (HSPCs). Using an ex vivo intact AGM culture system, we demonstrated that retrovirus-mediated GATA-2 expression in the +9.5-/- AGM rescues its hematopoietic defect. Thus, the reduced GATA-2 levels in the +9.5-/- AGM cause the HSC generation defect, and this rescue assay provides a unique system to decipher the downstream genetic network. To discover novel druggable regulators in the GATA-2 pathway to promote HSC generation, we profiled the expression pattern of all G-protein-coupled-receptors, which represent the most successful class of pharmaceutical targets, in the AGM using our RNA-seq dataset (+9.5+/+ vs. +9.5-/- AGM). This global GPCR analysis revealed four GATA-1 and GATA-2 co-regulated genes, Adora3, Gpr65, Ltb4r1, and Adora2b. Database mining revealed that only the Gpr65 expression pattern resembled that of Gata2. To evaluate GPR65 functions during HSC generation, we conducted an shRNA-based loss-of-function analysis in the AGM. While downregulating Gpr65 did not alter the abundance of the CD31+ c-Kit+ hematopoietic cell population, it significantly increased the CD31+ c-Kit+ Sca1+ HSC-containing cell population (1.4 fold, p<0.05), indicating that GPR65 suppresses HSC generation. To validate the involvement of GPR65 during the HSC generation process in vivo, we conducted a morpholino oligonucleotide (MO)-based loss-of-function study in zebrafish. In situ hybridization analysis revealed high Runx1/c-Myb expression (labeling definitive HSCs and progenitors) in 48% of embryos injected with Gpr65 MOs compared with 11% of wild type embryos. Consistent with the ex vivo AGM analysis, this increase in Runx1/c-Myb expression upon Gpr65 MO treatment suggests GPR65 is a negative regulator of HSC emergence in vivo. To dissect the molecular mechanism governing GPR65-suppressed HSC generation, we tested whether lowering Gpr65 levels altered the expression of key HSC regulators. Quantitative RT-PCR analysis revealed that downregulating Gpr65 by 60-70% in AGM CD31+ c-Kit- endothelialcells increased Gata2 mRNA by 2.9 fold (p<0.05), Gata2 primary transcripts by 3.9 fold (p<0.05), and elevated expression of the GATA-2 target gene Runx1 (2.9 fold, p<0.05). These results support a mechanism whereby GPR65-mediated Gata2 repression is an important determinant of GPR65-suppressed HSC generation. In addition to this important function in the AGM, Gpr65 knockdown studies in primary fetal liver HSPCs revealed GPR65 suppression of Gata2 transcription to the same magnitude as in the AGM. To determine if GPR65-mediated Gata2 repression requires the +9.5 site, we infected freshly isolated HSPCs from fetal livers heterozygous for the +9.5 site with retrovirus expressing shRNA targeting Gpr65. Quantitative RT-PCR with allele-specific primers revealed that Gpr65 knockdown significantly upregulates Gata2 primary transcripts from the wild type (3.1 fold, p<0.01), but not the 9.5 mutant, allele. These results establish a requirement of the +9.5 site for GPR65 to repress Gata2 transcription. As we reported that SetD8, the only enzyme known to monomethylate H4K20, represses Gata2 expression via the +9.5 site, we tested whether GPR65 represses Gata2 expression through SetD8. H4K20me1 ChIP revealed that downregulating Gpr65 significantly reduces H4K20me1 levels at the +9.5 site by 30% (p<0.005), suggesting that GPR65 repression of Gata2 transcription involves SetD8. Our studies indicate that a G-protein coupled receptor, GPR65, is negative regulator of HSC generation and establish a GATA-2-GPR65 Type Iincoherent feedforward loop that controls HSC generation, providing a foundation to develop new targets for expanding HSCs for transplantation therapies and a new druggable target to treat hematologic disorders. Disclosures Zon: FATE Therapeutics: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Other: Founder; Scholar Rock: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Other: Founder.

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Successful Plerixafor-Mediated Mobilization, Apheresis, and Lentiviral Vector Transduction of Hematopoietic Stem Cells in Patients with Severe Sickle Cell Disease

Blood ◽

10.1182/blood.v130.suppl_1.990.990 ◽

2017 ◽

Vol 130 (Suppl_1) ◽

pp. 990-990

Author(s):

John F Tisdale ◽

Francis J. Pierciey ◽

Rammurti Kamble ◽

Julie Kanter ◽

Lakshmanan Krishnamurti ◽

...

Keyword(s):

Sickle Cell Disease ◽

Board Of Directors ◽

Sickle Cell ◽

Research Funding ◽

Ex Vivo ◽

Cell Disease ◽

Employment Equity ◽

Advisory Committees ◽

Cd34 Cells ◽

Equity Ownership

Abstract Background Patients with severe sickle cell disease (SCD) may benefit from β-globin gene transfer into autologous hematopoietic stem cells (HSC). Successful HBB gene transfer requires vector-mediated transduction of primitive HSCs. Steady-state bone marrow (BM) is the default HSC source in patients with SCD. Normal human BM contains up to 30% CD34+CD19+ pro-B cells and other lineage-committed cell types (CD34dim) that will not contribute to improved long-term erythropoiesis via gene therapy; these cells mobilize at low rates. CD34+ cell yields from BM harvest (BMH) are typically lower than those after mobilization and peripheral blood (PB) apheresis; multiple rounds of BMH may be required to obtain adequate cell doses for autologous gene therapy (GT) protocols. As G-CSF can cause life-threatening SCD complications and is contraindicated, plerixafor, a CXCR4 receptor antagonist, may accomplish HSC mobilization without the neutrophil or endothelial activation that elicit vaso-occlusion. We modified the protocol for the HGB-206 phase 1 study of LentiGlobin GT in severe SCD (NCT02140554) to assess HSC mobilization with plerixafor alone, followed by apheresis and transduction of mobilized cells. We also characterized BM-derived and plerixafor-mobilized HSC populations from patients with SCD. Methods HGB-206 is a phase 1 study of LentiGlobin Drug Product (DP), which contains autologous HSCs transduced ex vivo with the betibeglogene darolentivec (BB305) lentiviral vector, in patients with severe SCD (defined as a history of recurrent vaso-occlusive crisis [VOC], acute chest syndrome, stroke, or tricuspid regurgitant jet velocity of >2.5 m/s). Patients in group B receive 240 µg/kg plerixafor followed 4-6 hours later by apheresis, processing ~3 total blood volumes to collect backup HSCs. If < 1.5 x 106 CD34+ cells are collected, patients undergo a second day of apheresis. Cells collected in excess of those required for backup in case of graft failure are transduced with BB305 lentiviral vector for exploratory analyses. Group B patients then proceed to BMH to obtain cells for clinical DP manufacture. Group C will receive DP manufactured from mobilized PB. Mass cytometry (CyTOF) was used to analyze ex vivo cultured CD34+ cells with over 35 cell surface markers. Results To date, 3 patients have undergone plerixafor mobilization. Patients had a transient 1.5- to 3-fold increase in peak white blood cell and absolute neutrophil levels after plerixafor. Peak absolute CD34+ cell counts in PB were 170, 58, and 160 x 106 CD34+ cells/liter. A total of 15.3, 5.6, and 9.0 x 106 CD34+ cells/kg were collected in a single day of apheresis, and no subsequent apheresis or mobilization was required. In the same study, a mean of 5.0 (range 0.3-10.8) x 106 CD34+ cells/kg were collected per BMH (N=21). The mobilization and apheresis procedures had an acceptable toxicity profile. No dose-limiting toxicities were observed after plerixafor dosing. One patient had a single VOC approximately 48 hours after receiving plerixafor; this patient also experienced VOCs of similar severity after BMH. In contrast, after 21 BMHs in 9 patients, 18 ≥ grade 3 AEs were reported in 6 patients, primarily pain. Ex vivo cultured CD34+ cells isolated from BMH consisted of an average of 41.0% (17.3%-50.7%) CD34dim cells, with 16%-50% of the CD34dim cells expressing lymphoid markers. In contrast, ex vivo cultured CD34+ cells isolated from plerixafor mobilized PB contained an average of 8.2% (1.5-19.5%) CD34dim cells. Similar drug product vector copy numbers were obtained after research-scale transduction of CD34+ cells from marrow and PB from the same patient. Conclusion Initial results suggest that obtaining adequate doses of CD34+ cells from plerixafor-mobilized PB of patients with SCD may be safe and feasible, without the life-threatening complications associated with G-CSF, and with fewer, less invasive procedures compared with BMH. PB-derived CD34+ cells may contain lower proportions of lineage-committed CD34+ cells than BM-derived cells from patients with SCD. Cells collected by BMH and PB mobilization/apheresis appear to have an equivalent transduction efficiency. Together these results indicate that it may be possible to use plerixafor-only mobilization in clinical studies of autologous HSC GT in SCD. Results of mobilization, apheresis, and DP manufacturing at clinical scale for additional patients will be available for presentation. Disclosures Pierciey: bluebird bio: Employment. Kanter: American Society of Hematology (Sickle Cell Disease Guideline Panel): Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; MUSC: Other: The site PI for sponsored research conducted at MUSC who receives funds from: Novartis, bluebird bio, GBT, Sancillo, Apopharma, Pfizer; NHLBI (sickle cell disease research advisory committee): Membership on an entity's Board of Directors or advisory committees, Research Funding; Sancillo: Research Funding; Apopharma: Research Funding; Pfizer: Research Funding; GBT: Research Funding; Bluebird Bio: Membership on an entity's Board of Directors or advisory committees, Research Funding. Kwiatkowski: Novartis: Research Funding; Bluebird Bio: Research Funding; Apopharma: Research Funding; Agios: Consultancy, Honoraria; Ionis: Consultancy, Honoraria. Thompson: Novartis: Consultancy, Research Funding; bluebird bio: Consultancy, Research Funding; Baxalta: Research Funding; Celgene: Consultancy, Research Funding. Shestopalov: bluebird bio: Employment, Equity Ownership. Bonner: bluebird bio: Employment, Equity Ownership. Joseney-Antoine: bluebird bio: Employment, Equity Ownership. Asmal: bluebird bio: Employment, Equity Ownership. Walters: bluebird bio: Research Funding; ViaCord Processing Lab: Other: Medical Director; Sangamo Therapeutics: Consultancy; AllCells, Inc: Other: Medical Director.

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Ex Vivo Expansion with E478 Increases the Rate of CRISPR-Mediated Homology Directed Repair of the Beta-Globin Gene in Human Hematopoietic Stem Cells By >10-Fold and Improves In Vivo Engraftment By >120-Fold

Blood ◽

10.1182/blood-2019-131157 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 4634-4634

Author(s):

Kevin A. Goncalves ◽

Megan D. Hoban ◽

Sharon L. Hyzy ◽

Katia S. George ◽

Anthony E. Boitano ◽

...

Keyword(s):

Ex Vivo ◽

Globin Gene ◽

Fold Increase ◽

Ex Vivo Expansion ◽

Gene Correction ◽

Employment Equity ◽

Hematopoietic Stem ◽

Cd34 Cells ◽

Equity Ownership

Background . Site-specific gene correction of hematopoietic stem cells (HSCs) via homology directed repair (HDR) has the potential to precisely repair defective genes and provide life-long cures for a variety of blood-based diseases. It is possible to obtain high levels of HDR during in vitro HSC culture, but these cells fail to robustly engraft in vivo, suggesting that the procedure of HDR compromises HSC function or that true HSCs are not undergoing HDR. Cells need to be actively cycling in order to undergo HDR, but conditions that allow HSC replication in vitro without compromising HSC number and function remain elusive. Thus, most HDR protocols minimize time in culture, potentially limiting HDR rates and cell yield. We recently reported that ex vivo expansion of HSCs with an aryl hydrocarbon receptor (AHR) antagonist is a clinically validated method to expand HSCs. The AHR antagonist-expanded CD34+ cell therapy, MGTA-456, results in rapid and durable recovery in patients with hematologic malignancies and inherited metabolic diseases (Wagner et al Cell Stem Cell 2016; Orchard et al AAN 2019). To apply this technology to gene-modified HSCs, we developed a novel AHR antagonist, E478, which expands NSG-engrafting cells 10-fold compared to uncultured primary human mobilized peripheral blood (mPB) CD34+cells in limit dilution studies. We previously showed that expansion with E478 results in up to 10-fold higher engraftment of lentiviral vector (LVV)-transduced cells and CRISPR/Cas9 knockout cells (Hoban et al ASGCT 2019). Here, we demonstrate that ex vivo expansion of mPB CD34+ cells with E478 results in >10-fold increase in rate of HDR and >120-fold increase in NSG engraftment of HDR+ cells compared to conventional approaches. Results . To determine whether more active cycling would lead to higher rates of HDR, we cultured cells for 1, 2, 3, and 4 days prior to electroporation with CRISPR gRNA targeting the beta-globin gene and transduction with a GFP-containing adeno-associated virus (AAV) donor template. Cell cycle analysis revealed that 33±1.8% of cells enriched for HSCs (CD34+CD90+ cells) remain quiescent after 2 days in culture, whereas 0.92±0.06% of CD34+CD90+ cells were quiescent after 3 and 4 days in culture (n=2 mPB donors). We then assessed HDR rates and HSC number after 1, 2, 3, and 4 days of additional culture. Compared to a conventional HDR protocol utilizing a 2-day pre-stimulation period followed by 1 day of culture after electroporation (herein called a 2+1 culture), we observed up to 8-fold increase in HDR with longer pre-stimulation periods, but this was accompanied with differentiation of CD34+CD90+ cells and loss of engraftment in NSG mice (79% decrease, p<0.001). We next evaluated whether E478 could increase the dose of HSCs and maintain high HDR rates. We cultured mPB CD34+ cells with E478 for a 4 day pre-stimulation, performed HDR, and continued the expansion for 4 days with E478 (herein called 4+4 culture). With the 4+4 protocol, we observed a 6-fold increase in the rate of HDR in vitro and a 134-fold increase in the number of CD34+CD90+ cells with E478 relative to 2+1 conditions with DMSO vehicle (n=2, p<0.01). Transplant of these cells into sublethally-irradiated NSG mice resulted in a 4-fold higher rate of engraftment (Figure A, p<0.01, n=8 mice), 12-fold higher rates of HDR (Figure B, p<0.001) and >120-fold increase in the number of HDR+ NSG-engrafting cells relative to 2+1 cultures (Figure C, p<0.001). Further, a 2+1 culture with E478 led to an 8-fold increase in number of HDR+ NSG-engrafting cells (p<0.001) relative to standard 2+1 approaches without a small molecule. Multi-lineage engraftment was observed in all groups. Studies using E478 with bone marrow from patients with sickle cell disease are in progress and will be presented. Conclusions. We demonstrate that ex vivo HSC expansion with E478 enables higher rates of HDR and a high dose of HDR+ HSCs, leading to >120-fold increase in the engraftment of HDR+ HSCs compared to conventional 2+1 approaches. Culture with E478 is a promising approach to realize the full potential of targeted gene correction in HSCs for a variety of genetic diseases. Disclosures Goncalves: Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties. Hoban:Magenta Therapeutics: Employment, Equity Ownership. Hyzy:Magenta Therapeutics: Employment, Equity Ownership. George:Magenta Therapeutics: Employment, Equity Ownership. Boitano:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties. Cooke:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties.

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Transient Inhibition of Transforming Growth Factor-β1 in Human Blood-Derived CD34+ Cells Enhances Survival and Proliferation in Vitro and Vascular Reparative functions In Vivo.

Blood ◽

10.1182/blood.v114.22.3546.3546 ◽

2009 ◽

Vol 114 (22) ◽

pp. 3546-3546

Author(s):

Stephen Bartelmez ◽

Ashay Bhatwadekar ◽

Patrick Iversen ◽

Francis W Ruscetti ◽

Maria Grant

Keyword(s):

Board Of Directors ◽

Research Funding ◽

Ex Vivo ◽

Cxcr4 Expression ◽

Employment Equity ◽

Advisory Committees ◽

Cd34 Cells ◽

Equity Ownership ◽

Tgf Β1

Abstract Abstract 3546 Poster Board III-483 CD34+ cells from diabetic patients demonstrate reduced vascular reparative function due to decreased proliferation as well as diminished migration prowess which is largely due to lower levels of bioavailable nitric oxide (NO). We asked whether a transient TGF-β1 blockade in CD34+ cells from diabetics would improve their reparative ability given that TGF-β is a key factor modulating stem cell quiescence. Peripheral blood lin-CD34+ cells or lin-CD34+CD38+/− cells were treated ex vivo with antisense phosphorodiamidate morpholino oligomers (TGF-β1 -PMO), demonstrated to inhibit TGF-β1 protein expression in stem cells. Cells were then analyzed for cell surface TGF-β Receptor 2 (TGF-β R2) and CXCR4 expression, their ability to generate NO, their ability to migrate toward SDF-1, their ability to survive in the absence of added growth factors, and tested in vivo for their vascular reparative ability. After TGF-β1-PMO treatment, healthy and diabetic CD34+CD38+ and - cells downregulated TGF-βR2, upregulated CXCR4 expression, survived in the absence of added growth factors ex vivo and migrated more efficiently to SDF-1 compared to controls. TGF-β1-PMO treated diabetic CD34+ cells restored NO production to non-diabetic levels. In contrast, TGF-β1-PMO did not enhance NO generation in CD34+ cells from healthy subjects. Using an in vivo retinal ischemia reperfusion model, we observed that TGF-β1-PMO treatment increased the ability of both healthy and diabetic CD34+ cells to home to injured capillaries compared to control PMO treated cells. As also observed in our current study, a reduction of TGF-β1 levels in murine hematopoietic stem cells correlates with a reduction in TGF-βR2 expression which may induce proliferation in vivo. We also show that both diabetic and healthy lin-CD34+CD38+ cells express TGF-βR2 by FACS. In contrast, only healthy lin-CD34+CD38- cells expressTGF-βR2 while diabetic lin-CD34+CD38 - cells express essentially no cell surface TGF-βR2 (<5 % of cells are TGF-βR2+). Our results suggest that a transient blockade of TGF-β1 may represent a promising therapeutic strategy in restoring vascular reparative function in diabetic CD34+ cells. Disclosures: Bartelmez: BetaStem Therapeutics: Employment, Equity Ownership, Head, SRB, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding. Iversen:AVI-Biopharma: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding.

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BKT140 Is a Novel CXCR4 Antagonist with Stem Cell Mobilization and Antimyeloma Effects: An Open-Label First Human Trial In Patients with Multiple Myeloma Undergoing Stem Cell Mobilization for Autologous Transplantation

Blood ◽

10.1182/blood.v116.21.2260.2260 ◽

2010 ◽

Vol 116 (21) ◽

pp. 2260-2260 ◽

Cited By ~ 9

Author(s):

Arnon Nagler ◽

Avichai Shimoni ◽

Irit Avivi ◽

Jacob M. Rowe ◽

Katia Beider ◽

...

Keyword(s):

Multiple Myeloma ◽

Stem Cell ◽

Board Of Directors ◽

Stem Cell Mobilization ◽

Employment Equity ◽

Advisory Committees ◽

Hematopoietic Stem ◽

Cd34 Cells ◽

Equity Ownership ◽

Cell Mobilization

Abstract Abstract 2260 Background: BKT140 is a high affinity CXCR4 inhibitor with an extended K off-rate. Pre-clinical studies in animal models with BKT140 showed a robust mobilization of white blood cells (WBC) and hematopoietic stem cells (HSC). Furthermore, BKT140 also showed a direct anti-tumor effect against human-derived multiple myeloma (MM), lymphoma and primary leukemia cells and cell lines in vitro and in vivo, causing significant apoptosis. Aims: To assess BKT140 toxicity (primary endpoints), the mobilization capacity of CD34+ hematopoietic progenitors and CD138 MM cells, and pharmacokinetic (PK) and pharmacodynamic (PD) (secondary endpoints). Methods: 16 MM patients in first CR/PR were included in a phase I/IIa study, in which escalating doses of BKT140 (30, 100,300,900 μg/kg) were administered together with a high-dose cyclophosphamide (Cy) (2 g/m2) and G-CSF (5 μg/Kg) for stem cell mobilization. G-CSF was started on day 5 post Cy and BKT140 was injected subcutaneously (SC) once on day 10. Toxicity, PK, and mobilization capacity (assessed by serial measurements of number of WBC and CD34+ and CD138+ cells) were measured pre- and post BKT140 administration. Results: BKT140 was well tolerated at all doses and none of the patients developed grade II-IV toxicity. BKT140 was rapidly absorbed with no observed lag time, with peak plasma concentrations occurring 0.5h after administration. Clearance was rapid, with a median terminal half-life of 0.69h. BKT140 administration resulted in a significant dose-dependent increase in the number of peripheral blood neutrophils, monocytes, lymphocytes, and CD34+ cells compared to the G-CSF/Cy individual patient baseline. The maximum increase in the number of WBC from baseline was observed within 8h following BKT140 injection, 2.5-, and 3.0-, 4.1- and 4.8-fold, for the 4 BKT140 doses, respectively. Furthermore, BKT140 administration resulted in a significant increase in the mean absolute PB CD34+ cells mobilized (6.6, 7.5, 11.2 and 20.6 ×106/kg) for the 4 BKT140 administered doses, respectively. Moreover, the number of aphaeresis was reduced from 2.25 procedures at the first two BKT140 doses to 1.25 and 1 aphaeresis at the highest BKT140 doses, respectively. An increase in the number of CD138+ cells was observed in 6 out of 6 pts that had CD138+ cells in their blood and were treated with lower doses of BKT140 (30 and 100 μg/kg). Interestingly, in pts that were treated with the highest doses of BKT140 (300 and 900 μg/kg) a reduced number of CD138+ cells was observed in 3 out of 7 pts that had CD138+ cells in their blood, whereas in 4 pts, an increase in the number of CD138+ cells was shown. Three pts who did not have CD138+ cells in their blood were not affected by BKT140. The BKT140 mobilized grafts were used for AutoSCT following 200 mg/m2 melphalan conditioning. Pts received an average of 5.3×106 CD34+ cells/kg. All transplanted pts rapidly engrafted (n=15). The median day for neutrophil (>500/mm3) and platelet (>20,000/mm3, >50,000/mm3,) was on day 11 (range, 0–13), day 11 (range, 0–14), and day 14 (range, 0–23), respectively. Conclusions: The current data suggests that BKT140 can safely be added to G-CSF-based harvesting regimens, can increase CD34+ cell mobilization and reduce the number of collection days. Furthermore, due to its ability to release MM cells from the bone marrow and stimulate their cell death, additional studies are warranted to further evaluate the effect of BKT140 as an anti-MM agent. Disclosures: Nagler: Biokine Therapeutics Ltd: Consultancy. Abraham: Biokine Therapeutics Ltd: Employment, Equity Ownership, Patents & Royalties. Wald: Biokine Therapeutics Ltd: Employment. Shaw: Biokine Therapeutics Ltd: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Eizenberg: Biokine Therapeutics Ltd: Employment, Equity Ownership, Patents & Royalties. Peled: Biokine Therapeutics Ltd: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding.

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Rapid and Robust Mobilization of CD34+ HSCs without G-CSF Following Administration of Mgta-145 Alone or in Combination with Plerixafor

Blood ◽

10.1182/blood-2019-127523 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 1961-1961

Author(s):

John F. DiPersio ◽

Jonathan Hoggatt ◽

Steven Devine ◽

Lukasz Biernat ◽

Haley Howell ◽

...

Keyword(s):

Single Dose ◽

Adverse Events ◽

Board Of Directors ◽

Preliminary Data ◽

Research Funding ◽

Fold Change ◽

Employment Equity ◽

Advisory Committees ◽

Cd34 Cells ◽

Equity Ownership

Background Granulocyte colony-stimulating factor (G-CSF) is the standard of care for mobilization of hematopoietic stem cells (HSCs). G-CSF requires 4-7 days of injections and often multiple aphereses to acquire sufficient CD34+ cells for transplant. The number of CD34+ HSCs mobilized can be variable and patients who fail to mobilize enough CD34+ cells are treated with the combination of G-CSF plus plerixafor. G-CSF use is associated with bone pain, nausea, headaches, fatigue, rare episodes of splenic rupture, and is contraindicated for patients with autoimmune and sickle cell disease. MGTA-145 (GroβT) is a CXCR2 agonist. MGTA-145, in combination with plerixafor, a CXCR4 inhibitor, has the potential to rapidly and reliably mobilize robust numbers of HSCs with a single dose and same-day apheresis for transplant that is free from G-CSF. MGTA-145 plus plerixafor work synergistically to rapidly mobilize HSCs in both mice and non-human primates (Hoggatt, Cell 2018; Goncalves, Blood 2018). Based on these data, Magenta initiated a Phase 1 dose-escalating study to evaluate the safety, PK and PD of MGTA-145 as a single agent and in combination with plerixafor. Methods This study consists of four parts. In Part A, healthy volunteers were dosed with MGTA-145 (0.0075 - 0.3 mg/kg) or placebo. In Part B, MGTA-145 dose levels from Part A were selected for use in combination with a clinically approved dose of plerixafor. In Part C, a single dose MGTA-145 plus plerixafor will be administered on day 1 and day 2. In Part D, MGTA-145 plus plerixafor will be administered followed by apheresis. Results MGTA-145 monotherapy was well tolerated in all subjects dosed (Table 1) with no significant adverse events. Some subjects experienced mild (Grade 1) transient lower back pain that dissipated within minutes. In the ongoing study, the combination of MGTA-145 with plerixafor was well tolerated, with some donors experiencing Grade 1 and 2 gastrointestinal adverse events commonly observed with plerixafor alone. Pharmacokinetic (PK) exposure and maximum plasma concentrations increased dose proportionally and were not affected by plerixafor (Fig 1A). Monotherapy of MGTA-145 resulted in an immediate increase in neutrophils (Fig 1B) and release of plasma MMP-9 (Fig 1C). Neutrophil mobilization plateaued within 1-hour post MGTA-145 at doses greater than 0.03 mg/kg. This plateau was followed by a rebound of neutrophil mobilization which correlated with re-expression of CXCR2 and presence of MGTA-145 at pharmacologically active levels. Markers of neutrophil activation were relatively unchanged (<2-fold vs baseline). A rapid and statistically significant increase in CD34+ cells occurred @ 0.03 and 0.075 mg/kg of MGTA-145 (p < 0.01) relative to placebo with peak mobilization (Fig 1D) 30 minutes post MGTA-145 (7-fold above baseline @ 0.03 mg/kg). To date, the combination of MGTA-145 plus plerixafor mobilized >20/µl CD34s in 92% (11/12) subjects compared to 50% (2/4) subjects receiving plerixafor alone. Preliminary data show that there was a significant increase in fold change relative to baseline in CD34+ cells (27x vs 13x) and phenotypic CD34+CD90+CD45RA- HSCs (38x vs 22x) mobilized by MGTA-145 with plerixafor. Mobilized CD34+ cells were detectable at 15 minutes with peak mobilization shifted 2 - 4 hours earlier for the combination vs plerixafor alone (4 - 6h vs 8 - 12h). Detailed results of single dose administration of MGTA-145 and plerixafor given on one day as well as also on two sequential days will be presented along with fully characterized graft analysis post apheresis from subjects given MGTA-145 and plerixafor. Conclusions MGTA-145 is safe and well tolerated, as a monotherapy and in combination with plerixafor and induced rapid and robust mobilization of significant numbers of HSCs with a single dose in all subjects to date. Kinetics of CD34+ cell mobilization for the combination was immediate (4x increase vs no change for plerixafor alone @ 15 min) suggesting the mechanism of action of MGTA-145 plus plerixafor is different from plerixafor alone. Preliminary data demonstrate that MGTA-145 when combined with plerixafor results in a significant increase in CD34+ fold change relative to plerixafor alone. Magenta Therapeutics intends to develop MGTA-145 as a first line mobilization product for blood cancers, autoimmune and genetic diseases and plans a Phase 2 study in multiple myeloma and non-Hodgkin lymphoma in 2020. Disclosures DiPersio: Magenta Therapeutics: Equity Ownership; NeoImmune Tech: Research Funding; Cellworks Group, Inc.: Membership on an entity's Board of Directors or advisory committees; Karyopharm Therapeutics: Consultancy; Incyte: Consultancy, Research Funding; RiverVest Venture Partners Arch Oncology: Consultancy, Membership on an entity's Board of Directors or advisory committees; WUGEN: Equity Ownership, Patents & Royalties, Research Funding; Macrogenics: Research Funding, Speakers Bureau; Bioline Rx: Research Funding, Speakers Bureau; Celgene: Consultancy; Amphivena Therapeutics: Consultancy, Research Funding. Hoggatt:Magenta Therapeutics: Consultancy, Equity Ownership, Research Funding. Devine:Kiadis Pharma: Other: Protocol development (via institution); Bristol Myers: Other: Grant for monitoring support & travel support; Magenta Therapeutics: Other: Travel support for advisory board; My employer (National Marrow Donor Program) has equity interest in Magenta. Biernat:Medpace, Inc.: Employment. Howell:Magenta Therapeutics: Employment, Equity Ownership. Schmelmer:Magenta Therapeutics: Employment, Equity Ownership. Neale:Magenta Therapeutics: Employment, Equity Ownership. Boitano:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties. Cooke:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties. Goncalves:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties. Raffel:Magenta Therapeutics: Employment, Equity Ownership. Falahee:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties. Morrow:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties. Davis:Magenta Therapeutics: Employment, Equity Ownership.

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Plerixafor (Mozobil ®)Plus G-CSF Is Effective in Mobilizing Hematopoietic Stem Cells in Patients with Concurrent Thrombocytopenia Undergoing Autologous Hematopoietic Stem Cell Transplantation.

Blood ◽

10.1182/blood.v114.22.3229.3229 ◽

2009 ◽

Vol 114 (22) ◽

pp. 3229-3229 ◽

Cited By ~ 1

Author(s):

Ivana N Micallef ◽

Eric Jacobsen ◽

Paul Shaughnessy ◽

Sachin Marulkar ◽

Purvi Mody ◽

...

Keyword(s):

Stem Cell ◽

Platelet Count ◽

Board Of Directors ◽

Research Funding ◽

Advisory Committees ◽

Hematopoietic Stem ◽

Platelet Counts ◽

Cd34 Cells ◽

Low Platelet Count ◽

Equity Ownership

Abstract Abstract 3229 Poster Board III-166 Introduction Low platelet count prior to mobilization is a significant predictive factor for mobilization failure in patients with non-Hodgkin's lymphoma (NHL) or Hodgkin's disease (HD) undergoing autologous hematopoietic stem cell (HSC) transplantation (auto-HSCT; Hosing C, et al, Am J Hematol. 2009). The purpose of this study is to assess the efficacy of HSC mobilization with plerixafor plus G-CSF in patients with concomitant thrombocytopenia undergoing auto-HSCT. Methods Patients who had failed successful HSC collection with any mobilization regimen were remobilized with plerixafor plus G-CSF as part of a compassionate use program (CUP). Mobilization failure was defined as the inability to collect 2 ×106 CD34+ cells/kg or inability to achieve a peripheral blood count of ≥10 CD34+ cells/μl without having undergone apheresis. As part of the CUP, G-CSF (10μg/kg) was administered subcutaneously (SC) every morning for 4 days. Plerixafor (0.24 mg/kg SC) was administered in the evening on Day 4, approximately 11 hours prior to the initiation of apheresis the following day. On Day 5, G-CSF was administered and apheresis was initiated. Plerixafor, G-CSF and apheresis were repeated daily until patients collected the minimum of 2 × 106 CD34+ cells/kg for auto-HSCT. Patients in the CUP with available data on pre-mobilization platelet counts were included in this analysis. While patients with a platelet count <85 × 109/L were excluded from the CUP, some patients received waivers and were included in this analysis. Efficacy of remobilization with plerixafor + G-CSF was evaluated in patients with platelet counts ≤ 100 × 109/L or ≤ 150 × 109/L. Results Of the 833 patients in the plerixafor CUP database, pre-mobilization platelet counts were available for 219 patients (NHL=115, MM=66, HD=20 and other=18.). Of these, 92 patients (NHL=49, MM=25, HD=8 and other=10) had pre-mobilization platelet counts ≤ 150 × 109/L; the median platelet count was 115 × 109/L (range, 50-150). The median age was 60 years (range 20-76) and 60.4% of the patients were male. Fifty-nine patients (64.1%) collected ≥2 × 109 CD34+ cells/kg and 13 patients (14.1%) achieved ≥5 × 106 CD34+ cells/kg. The median CD34+ cell yield was 2.56 × 106 CD34+ cells/kg. The proportion of patients proceeding to transplant was 68.5%. The median time to neutrophil and platelet engraftment was 12 days and 22 days, respectively. Similar results were obtained when efficacy of plerixafor + G-CSF was evaluated in 29 patients with platelet counts ≤ 100 × 109/L (NHL=12, MM=10, HD=3 and other=4). The median platelet count in these patients was 83 × 109/L (range, 50-100). The median age was 59 years (range 23-73) and 60.4% of the patients were male. The minimal and optimal cell dose was achieved in 19(65.5%) and 3(10.3%) patients, respectively. The median CD34+ cell yield was 2.92 × 106 CD34+ cells/kg. The proportion of patients proceeding to transplant was 62.1%. The median time to neutrophil and platelet engraftment was 12 days and 23 days, respectively. Conclusions For patients mobilized with G-CSF alone or chemotherapy ±G-CSF, a low platelet count prior to mobilization is a significant predictor of mobilization failure. These data demonstrate that in patients with thrombocytopenia who have failed prior mobilization attempts, remobilization with plerixafor plus G-CSF allows ∼65% of the patients to collect the minimal cell dose to proceed to transplantation. Thus, in patients predicted or proven to be poor mobilizers, addition of plerixafor may increase stem cell yields. Future studies should investigate the efficacy of plerixafor + G-CSF in front line mobilization in patients with low platelet counts prior to mobilization. Disclosures Micallef: Genzyme Corporation: Membership on an entity's Board of Directors or advisory committees, Research Funding. Jacobsen:Genzyme Corporation: Research Funding. Shaughnessy:Genzyme Corporation: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Marulkar:Genzyme Corporation: Employment, Equity Ownership. Mody:Genzyme Corporation: Employment, Equity Ownership. van Rhee:Genzyme Corporation: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.

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Mobilization with Plerixafor (Mozobil ®)Plus G-CSF Results in Superior Day 1 Collection of CD34+ Cells Compared to Placebo Plus G-CSF: Results From Two Randomized Placebo-Controlled Trials in Patients with Multiple Myeloma or Non-Hodgkin's Lymphoma.

Blood ◽

10.1182/blood.v114.22.3224.3224 ◽

2009 ◽

Vol 114 (22) ◽

pp. 3224-3224 ◽

Cited By ~ 1

Author(s):

Brian J. Bolwell ◽

Auayporn P. Nademanee ◽

Patrick Stiff ◽

Edward Stadtmauer ◽

Richard T. Maziarz ◽

...

Keyword(s):

Placebo Group ◽

Board Of Directors ◽

Research Funding ◽

Cell Yield ◽

P Value ◽

Employment Equity ◽

Advisory Committees ◽

Cell Dose ◽

Cd34 Cells ◽

Equity Ownership

Abstract Abstract 3224 Poster Board III-161 Background While most centers use 2 × 106 CD34+ cells/kg as the minimal cell dose for autologous hematopoietic stem cell (HSC) transplantation (auto-HSCT), infusion of higher CD34+ cell dose is associated with better outcomes in patients with multiple myeloma (MM) or non-Hodgkin's lymphoma (NHL). Recent evidence suggests a correlation between CD34+ cell yield on Day 1 of collection and total CD34+ cell yield as well as post-transplant outcomes. This analysis was designed to: 1) compare Day 1 collection between patients with NHL or MM mobilized with plerixafor plus G-CSF or placebo plus G-CSF; and 2) determine whether Day 1 CD34+ cell yields correlated with the total mobilization yield and number of apheresis days. Methods Data were obtained from two prospective, randomized, double-blind, placebo-controlled, phase 3 clinical trials that compared the safety and efficacy of plerixafor (0.24 mg/kg/day SQ) plus G-CSF (10 μg/kg/day) with placebo plus G-CSF for mobilization of HSC for auto-HSCT in patients with NHL (3101 Study) or MM (3102 Study). Pearson correlation coefficient was used to evaluate the association of day 1 CD34+ cell collection with total CD34+ cell yield and the number of days of apheresis. Results In the NHL trial, 150 patients were mobilized with plerixafor plus G-CSF and 148 patients underwent mobilization with placebo plus G-CSF. More than half the patients (55.3%) in the plerixafor group collected ≥2 × 106 CD34+ cells/kg on Day 1 of apheresis (Figure 1A). In contrast, 19.6% patients in the placebo group collected ≥ 2 × 106 CD34+ cells/kg on Day 1 of apheresis (p< 0.001). In the MM study, 148 patients were mobilized with plerixafor plus G-CSF and 154 patients were mobilized with placebo plus G-CSF. More than half the patients (52.7%) in the plerixafor group collected ≥6 × 106 CD34+ cells/kg on the first day of collection compared to only 16.9% patients in the placebo group (p<0.001; Figure 1B). There was a strong positive correlation between day 1 collection and the total CD34+ cell yield in patients with NHL (r= 0.86, p-value= <0.0001) or MM (r= 0.87, p-value= <0.0001) in both the plerixafor and placebo groups. For NHL patients, the median Day 1 collection was higher in the plerixafor group compared to the placebo group: 2.66 × 106 vs. 0.77 × 106 CD34+ cells/kg (p<0.001) and this translated into higher total CD34+ cell yields in the two groups respectively: 5.69 × 106 vs. 1.98 × 106 CD34+ cells/kg (p<0.001). Similarly, for MM patients, the median CD34+ cells/kg collected on Day 1 was higher in the plerixafor group compared to the placebo group: 7.01 × 106 vs. 2.29 × 106 CD34+ cells/kg (p<0.001) and this translated into better overall collection in the plerixafor vs. placebo groups: 10.96 × 106 vs. 6.18 × 106 CD34+ cells/kg (p<0.001). A negative correlation was observed between CD34+ cells collected on Day 1 and the number of days of apheresis performed in patients with NHL (r= -0.67, p-value=<0.0001) or MM (r= -0.50, p-value= <0.0001) in both the plerixafor and placebo groups. Consequently, better Day 1 collection in plerixafor-treated NHL or MM patients translated into significantly fewer apheresis days to achieve the target collection compared to placebo treated patients. Conclusions These data support previous reports demonstrating a strong correlation between day 1 CD34+ cell collection and total CD34+ cell yield and apheresis days. These data also demonstrate that addition of plerixafor to G-CSF allows significantly more patients to achieve the target cell collection within 1 day of apheresis compared to G-CSF alone. These findings support the observation that mobilization with plerixafor plus G-CSF reduces the number of apheresis days required to achieve the minimal or optimal cell dose to proceed to transplantation. Disclosures Bolwell: Genzyme Corporation: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Nademanee:Genzyme Corporation: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Stiff:Genzyme Corp.: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Stadtmauer:Genzyme Corporation: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Maziarz:Genzyme Corp.: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Micallef:Genzyme Corporation: Membership on an entity's Board of Directors or advisory committees, Research Funding. Marulkar:Genzyme Corporation: Employment, Equity Ownership. Gandhi:Genzyme Corporation: Employment, Equity Ownership. DiPersio:Genzyme: Honoraria.

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Diacylglycerol Enhances Hematopoietic Stem/Progenitor Cell Development and Engraftment Via MAP Kinase Activation

Blood ◽

10.1182/blood.v122.21.174.174 ◽

2013 ◽

Vol 122 (21) ◽

pp. 174-174

Author(s):

Vera Binder ◽

Pulin Li ◽

Francesca Barrett ◽

Alex Leung ◽

Leonard I. Zon

Keyword(s):

Cord Blood ◽

Map Kinase ◽

Board Of Directors ◽

Marrow Transplantation ◽

Fluorescent Protein ◽

Advisory Committees ◽

Hematopoietic Stem ◽

Cd34 Cells ◽

Equity Ownership ◽

Marrow Cells

Abstract Hematopoietic stem and progenitor cells (HSPCs) are exposed to a variety of intrinsic and extrinsic factors regulating all processes needed during development, and for successful engraftment after transplantation. In order to decipher the molecular pathways that may promote engraftment of HSPCs after marrow transplantation, we performed a competitive transplantation screen using chemical genetics in zebrafish. Green fluorescent protein-labeled kidney marrow cells (equivalent to mammalian bone marrow cells) were treated ex vivo with single compounds of a chemical library of known biologically active compounds, and administered by retro-orbital venous injection to lethally irradiated recipient zebrafish. About 500 chemicals were screened. Untreated kidney marrow cells labeled with a red fluorescent protein were used as competitors. Imaging-based assessment of short-term engraftment demonstrated that 1,2-Didecanoylglycerol, a membrane permeable but non-physiologic analogue of diacylglycerol (DAG), significantly improved engraftment compared to competitor cells. Follow-up by FACS analysis showed a 3.5 fold increase of long-term repopulating units after DAG treatment. To interrogate whether DAG treatment not only affects HSPCs under transplant conditions, but also during normal embryonic development, we treated zebrafish embryos within the time window of HSC formation in the dorsal aorta. DAG treatment increased expression of the HSPC markers Runx1 and c-myb in the AGM (Aorto-Gonad-Mesonephros). Treatment after HSC specification also led to an upregulation of HSPC markers in the caudal hematopoietic tissue (equivalent to fetal liver in mammals). These data suggest that DAG affects not only HSC formation, but also migration and engraftment of HSPCs as hematopoiesis transitions from the AGM to the CHT during development. To determine whether HSPCs respond to DAG in a cell autonomous manner, and to identify the underlying molecular mechanism, we treated human CD34+ cells from umbilical cord blood with DAG and performed RNA-seq analysis. Ingenuity Pathway Analysis of the 395 differentially expressed genes (q-value < 0.05) implicated the MAP kinase pathway as an upstream regulator. Human Phosphokinase array analysis of treated CD34+ showed ERK 1/2 activation. DAG is known to activate Protein Kinase C (PKC) with subsequent Raf kinase phosphorylation, which has the potential to activate ERK. Co-treatment of CD34+ cells with DAG and the ERK inhibitor PD98059 blocked upregulation of downstream ERK-targets (e.g. AREG, CSF2, EGR1, HMOX, SERPINE1, DUSP4, DUSP6), whereas the PI3K family inhibitor LY294002 and the p38 MAP kinase inhibitor SB202190 did not alter the effect of DAG on expression of these genes. This demonstrates that DAG activates ERK and its downstream targets. Our competitive marrow transplantation-based chemical screen has led to the discovery of 1,2-Didecanoylglycerol as a novel modulator of HSPC development and engraftment after transplantation. This discovery may be of clinical relevance to marrow or cord blood hematopoietic stem cell transplantation. Disclosures: Zon: FATE Therapeutics, Inc: Consultancy, Equity Ownership, Founder Other, Membership on an entity’s Board of Directors or advisory committees, Patents & Royalties; Stemgent, Inc: Consultancy, Membership on an entity’s Board of Directors or advisory committees, Stocks, Stocks Other; Scholar Rock: Consultancy, Equity Ownership, Founder, Founder Other, Membership on an entity’s Board of Directors or advisory committees, Patents & Royalties.

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