Axl blockade in vitro and in patients with high-risk MDS by the small molecule inhibitor BGB324.

2017 ◽  
Vol 35 (15_suppl) ◽  
pp. 7059-7059 ◽  
Author(s):  
Sonja Loges ◽  
Isabel Ben Batalla ◽  
Michael Heuser ◽  
Nikolas Berenbrok ◽  
Thomas Schroeder ◽  
...  
Keyword(s):  
Bone Marrow ◽  
High Risk ◽  
Adverse Events ◽  
Small Molecule ◽  
Small Molecule Inhibitor ◽  
Loading Dose ◽  
Bone Marrow Stroma ◽  
Healthy Donors ◽  
Molecule Inhibitor ◽  
Marrow Stroma

7059 Background: The interplay with bone marrow stroma plays an important role in the pathobiology of MDS. Gas6 is secreted by mesenchymal bone marrow stroma cells and promotes survival and therapy resistance of AML cells expressing the Axl receptor. We hypothesized that inhibiting Axl by the small molecule inhibitor BGB324 might hold therapeutic potential in MDS. Methods: We investigated the inhibitory effect of BGB324 on primary bone marrow mononucleated cells (BMMNC) and mesenchymal stroma cells (MSC) from MDS patients in comparison to healthy donors. In the ongoing first-in-patient Phase 1a/b trial BGBC003 A standard 3 + 3 dose escalation study was performed to identify the maximum tolerated dose of BGB324 in patients with previously treated high risk MDS or AML. BGB324 was administered as an oral loading dose on days one and two followed by a reduced daily maintenance. Three dose levels were explored 400/100mg, 600/200mg and 900/300mg. Results: We found that BGB324 inhibited BMMNC from low- and high-risk MDS patients with an IC50 of 2.1 µM and 3.8 µM, respectively (n = 5). In comparison, BMNNC from healthy donors were resistant to BGB324 (IC50 9.4 µM, p < 0.05, n = 10). Axl expression was present in MSC isolated from the BM of MDS patients and BGB324 inhibited the proliferation of MSC from low- and high-risk MDS patients (IC50 2.5 µM and 2.7 µM, respectively; n = 7/5).To date, 3 patients with MDS were treated with 400 mg loading dose and 100 mg maintenance dose of BGB324. Therapy has been well-tolerated and the MTD has not yet been reached. The majority of adverse events reported have been Grade 1 and 2. The most common related adverse events are diarrhea and fatigue. One patient with MDS was treated for 80 weeks and experienced a PR. Evidence of target inhibition was demonstrated by almost complete inhibition of Axl phosphorylation accompanied by reduction in phosphoErk and phosphoAkt signalling at day 21 of treatment. Conclusions: BGB324 is well-tolerated and might represent a promising novel treatment approach in MDS. Safety and efficacy of BGB324 will be explored further in clinical trials. Clinical trial information: NCT02488408.

Aberrant Expression Of miRNA and mRNA Of Cell Cycle and Adhesion-Related Genes In Bone Marrow Stroma Cells Derived From Patients With Multiple Myeloma

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3149-3149 ◽  
Author(s):  
Rimma Berenstein ◽  
Blau Igor Wolfgang ◽  
Axel Nogai ◽  
Marlies Wächter ◽  
Antonio Pezzutto ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Multiple Myeloma ◽  
Bone Marrow ◽  
Genetic Alterations ◽  
Bone Marrow Stroma ◽  
Aberrant Expression ◽  
Healthy Donors ◽  
Marrow Stroma ◽  
Bone Marrow Stroma Cells

Abstract Multiple myeloma (MM) is a B-cell malignancy characterized by accumulation of malignant plasma cells (PC) within the bone marrow. The bone marrow microenvironment such as bone marrow stroma cells (BMSC) supports MM disease progression, resistance to chemotherapy, protects the tumor cells against apoptosis and causes osteolytic bone disease and angiogenesis. The aim of this study was to identify constitutive genetic alterations in BMSC derived from patients with MM (MM-BMSC) in comparison to BMSC from healthy donors. For BMSC selection, mononuclear cells were isolated from fresh bone marrow aspirates and were further expanded in cell culture. We studied 25 MM patients and 5 healthy donors. Senescence status was determined in passage 1 of cell cultures. MM-BSMC displayed a considerably higher percentage of senescence cells (p<0,05). We investigated the expression of cell cycle and adhesion-associated genes (CCNE1, CCND1, CDKN1B, VCAM, ICAM, IKK-alpha) in BMSC (passage 4) using SYBR-Green Real-Time PCR and relative quantification by linear regression. A downregulation of CCNE1 (p=0,05), CDKN1B (p=0,29), and an upregulation of CCND1 (p=0,05), VCAM-1 (p=0,33), ICAM-1 (p=0,33), and IKK-alpha (p=0,05) was demonstrated. Furthermore, the expression profile of miRNAs, targeting the analyzed mRNA genes or correlating with senescence, was studied (miR-16, miR-221, miR-126, miR-223, miR-485-5p and miR-519d). For miRNA detection treatment with Poly(A)-Polymerase and cDNA-Synthesis with a Poly(T)VN-Adaptor primer were carried out following an amplification with an universal reverse primer corresponding to the adaptor sequence and a miRNA-specific primer. miR-16, miR-223, miR-485-5p and miR-519d were significantly upregulated, (p=0,02; p=0,004; p=0,02; and p=0,002, respectively), whereas miR-221 and miR-126 showed no considerable differences to BMSC obtained from healthy donors. Next we investigated incubation of immunmodulatory drug Lenalidomid in BMSC cultures. Cells were treated with 10 µM Lenalidomid over 72 hours and expression was normalized to a 0,01 % DMSO control. Significant difference in gene expression were visible for ICAM-1 (p=0,01). For CDKN1B (p=0,16) and VCAM-1 (p=0,12) we demonstrated changes in gene expression. Our results indicate aberrant expression of cell cycle and adhesion-related genes, such as CCNE1, CCND1 and CDKN1B VCAM-1, ICAM-1 and IKK-alpha in MM-BMSC as compared with healthy donors. Furthermore, we found significant upregulation of miR-16, miR-223, miR-485-5p and miR-519d. Further investigation are needed to determine molecular mechanisms in MM-BMSC and PC interaction that lead to constitutive changes in BMSC characteristics and gene expression patterns. Disclosures: No relevant conflicts of interest to declare.

Small Molecule Inhibitor of Neutrophil Elastase Normalizes Myeloid Differentiation and Improves Impaired Cell Survival Triggered by Elastase Mutations In Patients with Severe Congenital Neutropenia and Acute Myeloid Leukemia

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 386-386
Author(s):  
Andrew A. Aprikyan ◽  
Vahagn Makaryan ◽  
Maxim Totrov ◽  
Ruben Abagyan ◽  
David C. Dale
Keyword(s):  
Bone Marrow ◽  
Small Molecule ◽  
Neutrophil Elastase ◽  
Myeloid Leukemia ◽  
Small Molecule Inhibitor ◽  
Myeloid Differentiation ◽  
Severe Congenital Neutropenia ◽  
Wild Type ◽  
Congenital Neutropenia ◽  
Molecule Inhibitor

Abstract Abstract 386 Heterozygous mutations in the neutrophil elastase gene ELANE have been identified as the primary cause of severe congenital neutropenia (SCN) associated with recurring severe infections and evolution to acute myeloid leukemia (AML). As of today, more than 50 substitution, truncation, insertion and deletion mutations have been identified. Animal studies based on knock-in or knockout of ELANE in mice failed to produce severe neutropenia phenotype. We and others previously reported that expression of various mutants but not wild type neutrophil elastase (NE) in human but not murine cells triggers accelerated apoptosis. We also reported that expression of mutant NE (del.145-152), identified in SCN patients one of whom evolved to develop MDS/AML, in human promyelocytic tet-off HL60 cells causes both accelerated apoptosis and characteristic block of myeloid differentiation similar to that seen in bone marrow of SCN patients. Examination of the tertiary structure of NE revealed that most of the mutations leave the active site of the mutant protease intact. We identified a small molecule inhibitor of neutrophil elastase, a derivative of L-malic acid (Merck, USA), that blocked the proteolytic activity of NE by approximately 80% and was capable of restoring impaired myeloid differentiation and normalizing production of myeloid cells expressing del145-152 NE mutant. It is important to note that block of proteolytic activity of NE with the NE-SMI had no adverse effect on control human myeloid progenitor cells expressing wild type NE, thus confirming the gain-of-function effect of NE mutants. More than 20% of SCN patients with NE mutations evolve to develop AML. Molecular modeling and analysis of the tertiary structures of NE available through the Protein Database revealed that 16 different mutations identified in AML patients affect predominantly the N95 or N144 glycosylation sites or the binding pocket of the protease suggesting that altered substrate specificity of the mutant enzyme is the cause of accelerated apoptosis and block of myeloid differentiation in SCN/AML. We sought to obtain bone marrow samples from 2 unrelated SCN/AML patients both on G-CSF treatment harboring either C122Y or insPQ94. Bone marrow purified CD34+ and/or CD34-/CD33+ myeloid progenitors from the patients showed basal level of apoptosis in a range of 20–25%, which gradually increased reaching 40–50% apoptosis by 3 days of culture. Importantly, treatment of primary bone marrow-derived cells with NE-SMI substantially reduced accelerated apoptosis to near initial rate with approximately up to 2-fold reduction of apoptosis by 3 days of culture as determined by flow cytometry. Thus, our findings demonstrate that 1) small molecule inhibitor of neutrophil elastase is effective in blocking accelerated apoptosis triggered by three different NE mutations identified in SCN patients evolved to develop MDS/AML and 2) the small molecule inhibitor of NE is a promising therapeutic agent that should be considered for testing in clinical trials in SCN/AML patients. Disclosures: Dale: Amgen: Consultancy, Research Funding; Merck: Patents & Royalties, Research Support.

scholarly journals The Small Molecule Inhibitor G6 Significantly Reduces Bone Marrow Fibrosis and the Mutant Burden in a Mouse Model of Jak2-Mediated Myelofibrosis

2012 ◽  
Vol 181 (3) ◽  
pp. 858-865 ◽  
Author(s):  
Annet Kirabo ◽  
Sung O. Park ◽  
Heather L. Wamsley ◽  
Meghanath Gali ◽  
Rebekah Baskin ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Mouse Model ◽  
Small Molecule ◽  
Small Molecule Inhibitor ◽  
Bone Marrow Fibrosis ◽  
Molecule Inhibitor ◽  
Marrow Fibrosis

A Small Molecule Inhibitor Targeting CREB and CBP Inhibits Proliferation of AML Cells In Vitro and In Vivo,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3607-3607
Author(s):  
Grace I Aldana-Masangkay ◽  
Bryan Mitton ◽  
Alan K Ikeda ◽  
Kazunari Yamada ◽  
Bingbing Li ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Cell Proliferation ◽  
Small Molecule ◽  
Binding Protein ◽  
Small Molecule Inhibitor ◽  
Pharmacokinetic Analysis ◽  
Serum Drug Concentration ◽  
Molecule Inhibitor

Abstract Abstract 3607 The cAMP Response Element Binding Protein, CREB, is a nuclear transcription factor that is a downstream target of signaling pathways regulating memory, glucose homeostasis, cell proliferation, differentiation, and survival. We previously demonstrated that CREB is overexpressed at both the protein and mRNA levels in leukemia blasts and in leukemia stem cells. AML patients who overexpress CREB in their bone marrow have an increased risk of relapse and decreased event-free survival. To determine whether CREB is sufficient for leukemogenesis, we created a transgenic mouse in which CREB is expressed under the control of a myeloid specific hMRP8 promoter. Bone marrow progenitors from CREB transgenic mice had higher proliferative potential and replating ability. These mice developed myeloproliferative disease after one year but not acute leukemia, suggesting that CREB is not sufficient to induce myeloid transformation. To determine whether CREB is necessary for leukemia cell proliferation, we transduced AML cells with lentiviral CREB shRNA. We observed that downregulation of CREB led to decreased AML cell proliferation and survival in vitro. Furthermore, our results demonstrated that CREB knockdown inhibits the growth of AML cells in vivo without affecting normal hematopoietic stem cell function. Together, these results strongly suggest that CREB acts as a proto-oncogene and is a potential target for AML therapy. CREB is activated through phosphorylation, leading to the recruitment of the histone acetyltransferase, CREB binding protein (CBP) and subsequent target gene expression. XX-650-23 (MW: 288.3) is a small molecule that was identified through in silico screening methods to inhibit the interaction between CREB and CBP. We tested the effects of the drug on various AML cell lines using MTT assays and trypan blue exclusion. The IC50 ranged from 700 nM to 2 μM after 72 hours of drug treatment. However, treatment of normal human bone marrow progenitors cultured in methylcellulose containing XX-650-23 at a concentration of 10 μM had no effect on colony numbers. We also tested the in vivo effects of XX-650-23 using xenograft NOD-SCID IL-2Rgamma null (NSG) mouse models. To assess toxicity, mice were treated with the drug at various concentrations, ranging from 10 to 20 mg/kg, by intraperitoneal injection (IP) once daily for 28 days. We did not observe any weight loss or hematologic, renal, hepatic, or cardiac toxicity in the mice. We also performed pharmacokinetic analysis to determine the half-life and stability of the drug. After 1 hour of treatment, the serum drug concentration was 33 nM. The estimated drug mean residence time was 7.5 hours. Plasma clearance divided by IP absorption fraction was 9.6 L/min/kg. The mice were treated daily with drug (17.5mg/kg IP) or vehicle control once MV4-11 cells reached a tumor size of 300mm3 or at the time cells were injected. Our results demonstrated significant inhibition of tumor growth with treatment of the drug started on the day of injection of cells compared to waiting until the tumor reached 300mm3. Together, these data suggest that a small molecule inhibitor targeting CREB and CBP interaction is a potential avenue for drug development. We are currently studying the mechanisms by which XX-650-23 inhibits AML cell proliferation and analyzing the effects of combining the drug with chemotherapy. Disclosures: No relevant conflicts of interest to declare.

RGB 286638, a Novel Multi-Targeted Small Molecule Inhibitor, Induces Multiple Myeloma (MM) Cell Death through Abrogation of CDKDependent and Independent Survival Mechanisms

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2759-2759 ◽  
Author(s):  
Diana Cirstea ◽  
Teru Hideshima ◽  
Samantha Pozzi ◽  
Sonia Vallet ◽  
Hiroshi Ikeda ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Multiple Myeloma ◽  
Bone Marrow ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Small Molecule ◽  
Small Molecule Inhibitor ◽  
Janus Kinase ◽  
Transcriptional Networks ◽  
Molecule Inhibitor

Abstract Uncontrolled proliferation and development of drug resistance in multiple myeloma (MM) cells are consequences of the numerous genetic aberrations which are further stimulated in the context of bone marrow microenvironment. Thus, inhibition of complementary pro-survival signaling and transcriptional networks rather than individual pathway is required for induction of optimal cytotoxicity in MM cells. Recent studies have shown that cyclin-dependent kinases inhibitors (CDKIs), designed to block cell cycle progression through inhibition of CDK/cyclin complexes, block transcription through suppression of RNA polymerase II phosphorylation at its C-terminal domain (CTD), resulting in downregulation of cell proliferation (cyclins: D, A, B1, pRb) and anti-apoptotic proteins (i.e. Mcl-1, survivin, XIAP). Here we examined the anti-MM activity of RGB 286638, a novel multi-targeted small molecule inhibitor, originally designed to induce broad cell cycle suppression via multiple CDK inhibition. Treatment with RGB 286638 triggered a dose-dependent cytotoxicity in conventional drug-sensitive (MM.1S, RPMI 8226, U266, OPM2), and resistant (MM.1R, Dox-40, LR5) MM cell lines, as well as primary tumor cells from MM patients. Induction of apoptosis was evidenced by Annexin V/PI staining, and confirmed by PARP and caspase cleavage. Additionally, RGB 286638 overcame the proliferative advantage conferred by MM patient-derived bone marrow stromal cells (BMSCs) and cytokines (IL-6, IGF-1) on MM cells. To determine molecular mechanisms responsible for RGB 286638-induced cytotoxicity, we assessed the cell cycle profile, which revealed G2/M arrest followed by increased sub-G1 phase. Importantly, RGB 286638 inhibited phosphorylation of RNA polymerase II in a dose- and a time-dependent fashion, followed by suppression of CDK1/cyclin B, CDK4, 6/Cyclin D1, D3, and CDK2/Cyclin E complexes associated with rapid down-regulation of Rb phosphorylation. Interestingly, RGB 286638 effectively reduced IL-6-induced signal transducer and activator of transcription 3 (STAT3) phosphorylation (Tyr705) and Janus kinase 2 (JAK2) phosphorylation (Tyr 1007/1008), suggesting that RGB 286638 is a possible JAK2 inhibitor. Based on sufficient in vitro cytotoxicity, we examined anti-tumor activity of RGB 286638 in vivo using a human MM cell xenograft model in SCID mice and demonstrated that RGB 286638 inhibited tumor growth and prolonged survival. In conclusion, our data demonstrate preclinical activity and provide the rational to test RGB 286638 in the treatment of MM.

The bone marrow stroma capacity to confer resistance to leukemia cells from Ara-C treatment as a prognostic factor for overall survival in AML.

2019 ◽  
Vol 37 (15_suppl) ◽  
pp. e18500-e18500
Author(s):  
Patricia Macanas-Pirard ◽  
Sergio Vargas-Salas ◽  
Richard Broekhuizen ◽  
Romina Coronado ◽  
Carolina Bizama ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Overall Survival ◽  
Stem Cell ◽  
Prognostic Factor ◽  
Leukemia Cells ◽  
Stem Cell Markers ◽  
Bone Marrow Stroma ◽  
Control Medium ◽  
Healthy Donors ◽  
Marrow Stroma

e18500 Background: The interaction of acute myeloid leukemia (AML) with the bone marrow stroma (BMS) determines a protective microenvironment that favors leukemia development and resistance to chemotherapy. We developed an in vitro platform to study leukemia and stroma interaction, and showed that BMS secretes soluble factors protecting AML cells from Ara-C-induced apoptosis, which correlated with clinical patient outcomes. Methods: BMS from AML patients and healthy donors were cultured to perform chemo-sensitivity studies with Ara-C on THP-1 cells. A Resistance Factor was calculated (RF = IC50 stroma conditioned medium (CM)/IC50 control medium) to classify BMS as “protective” (PS: confers chemo-resistance) or “non-protective” (NPS: does not confer chemo-resistance). Characterization of myofibroblasts in BMS cultures was performed by WB. Quantification of cytokines from primary BMS CM was performed by Luminex. The differential expression of epithelial-mesenquimal-like (EMT-like) and stem cell-markers in THP-1 cells incubated with primary BMS CM was measured by qPCR. Results: We recruited 90 AML patients and 10 healthy BM donors. AML cohort showed 31 patients with PS and 59 patients with NPS. PS patients had a significant poor overall survival (OS) compared with NPS patients (44% versus 70% OS in 2.5 years, median survival 7.3 months versus 20.7 months, HR 2.36). The stroma from healthy BM donors did not confer resistance to THP-1 cells. BMS in both, PS and NPS have activated myofibroblasts and analysis of cytokine expression showed differential expression between groups. THP-1 cells incubated with PS showed significant expression of EMT- and stem cell-markers like Twist, Vimentin, CD44 and CD34 compared to THP-1 cells incubated with NPS and control medium. Conclusions: The capacity of the BMS from AML patients to modulate chemoresistance is a strong prognostic factor for OS, and PS patients have a worst OS compared with NPS patients. Stroma from healthy donors has a NPS phenotype. We propose that the leukemia is capable of educating the stroma to acquire secondarily the capacity to confer resistance to leukemia cells to favor tumor progression and chemoresistance.

scholarly journals A Small Molecule Inhibitor Selectively Induces Apoptosis in Cells Transformed by High Risk Human Papilloma Viruses

PLoS ONE ◽  
2016 ◽  
Vol 11 (6) ◽  
pp. e0155909
Author(s):  
Amy K. Sheaffer ◽  
Min S. Lee ◽  
Huilin Qi ◽  
Susan Chaniewski ◽  
Xiaofan Zheng ◽  
...  
Keyword(s):  
High Risk ◽  
Small Molecule ◽  
Small Molecule Inhibitor ◽  
Human Papilloma Viruses ◽  
Molecule Inhibitor ◽  
In Cells

Small Molecule Inhibitor of Neutrophil Elastase and Severe Congenital Neutropenia.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 552-552
Author(s):  
Andrew A Aprikyan ◽  
Vahagn Makaryan ◽  
Maxim Totrov ◽  
Ruben Abagyan ◽  
David C. Dale
Keyword(s):  
Bone Marrow ◽  
Progenitor Cells ◽  
Small Molecule ◽  
Small Molecule Inhibitor ◽  
Myeloid Differentiation ◽  
Cellular Model ◽  
Severe Congenital Neutropenia ◽  
Congenital Neutropenia ◽  
Compound A ◽  
Molecule Inhibitor

Abstract Abstract 552 Severe congenital neutropenia (SCN) is a rare heritable hematopoietic disorder characterized by maturation arrest at the promyelocytes, recurring severe infections, and evolution to leukemia. Heterozygous mutations in the neutrophil elastase (NE or ELANE) gene (sporadic or autosomal-dominant SCN) or homozygous mutations in the HAX1 gene (autosomal-recessive SCN) are associated with similar clinical phenotype and a block of myeloid differentiation or “maturation arrest” in the marrow. We and others reported that human myeloid progenitor cells expressing mutant elastase exhibit impaired cell survival (Aprikyan et al, 2003, Massullo et al, 2005, Kollner et al, 2006, Grenda et al, 2007). The hetero- and homozygous deletion of NE as well as the knock-in of mutant NE identified in SCN/AML patient failed to produce severe neutropenia phenotype in mice. Thus, the pathomechanism of severe neutropenia remains largely unclear due to the lack of cellular or animal model of SCN with characteristic block of myeloid differentiation and accelerated apoptosis. We established a cellular model of SCN with inducible tet-regulated expression of del.145-152 NE mutant (identified in SCN/AML patients) in human promyelocytic tet-off HL60 cells. The ratio of normal/mutant NE products in these cells is approximately 1:1, which is similar to that expected in SCN patients with heterozygous NE mutation. Expression of mutant NE in the promyelocytic cells results in a characteristic block of myeloid differentiation with ∼70% decline in differentiated neutrophils which is similar to that observed in SCN, whereas induced expression of control wild type NE has no effect on myeloid differentiation. Reduced production of myeloid cells and accelerated apoptosis are also observed upon DMSO or retinoic acid induced granulocytic differentiation of the cells in response to mutant, but not wild type NE expression. Thus, this cellular model of SCN appears to closely recapitulate the human phenotype. Expression of mutant NE resulted in approximately 40% increase in total NE-specific proteolytic activity, suggesting that mutant elastase exhibits at least some proteolytic activity. To date there are more than 50 heterozygous mutations in the NE gene have been identified in pre-leukemic SCN patients. Molecular modeling of the NE tertiary structure revealed that these mutations predominantly affect the N-glycosylation sites or the binding pocket of neutrophil elastase. Importantly, the active site of the mutant protease appears to be intact, which suggests that NE-specific small molecule inhibitors may be useful in preventing accelerated apoptosis and the characteristic block of myeloid differentiation of myeloid progenitor cells. Screening this cellular model of SCN, we identified a proprietary cell-penetrant elastase-specific small molecule inhibitor (compound A, Merck, USA), which inhibits the proteolytic activity of NE by more than 80%. When treated with compound A, control cells with induced expression of wtNE exhibit normal myeloid differentiation and production of myeloid cells, similar to that in untreated cells. These data suggest that human NE is dispensable and that accelerated apoptosis and impaired myeloid differentiation in SCN is due to a gain-of-function effect of pro-apoptotic mutant elastase. Importantly, treatment of human promyelocytic cells expressing del.145-152 mutant NE with this small molecule inhibitor restores impaired production of myeloid cells and improves myeloid differentiation to near normal levels, thus neutralizing the pro-apoptotic effect of mutant NE. These data suggest that small molecule inhibitors of NE may represent a promising therapy in severe congenital neutropenia. We have examined the effect of the inhibitor on bone marrow cells from an SCN patient positive for NE mutation. At the time of bone marrow aspiration the patient was on G-CSF and the patient's freshly isolated bone marrow CD33+ progenitor cells exhibited ∼21% apoptosis, which was gradually increased reaching 43% at 3 days of culture. However, daily treatment of SCN cells with compound A preserved the cell survival rate at the initial value resulting in approximately 2-fold reduction in apoptotic cell death at 3 days of culture. These data demonstrate that the small molecule inhibitor of NE and its analogs should be considered for clinical trials in patients with SCN that is attributable to mutant NE. Disclosures: Dale: Merck: Research support; Amgen: Consultancy, Research Funding, Speaker.

Sign in / Sign up

Export Citation Format

Share Document