scholarly journals CD97 Expression in Acute Myeloid Leukemia Is Associated with FLT3-ITD Mutation Status

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 1001-1001
Author(s):  
Manja Wobus ◽  
Martin Bornhäuser ◽  
Claudia Ortlepp ◽  
Angela Jacobi ◽  
Gerhard Ehninger ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Acute Myeloid Leukemia ◽  
Cell Lines ◽  
Myeloid Leukemia ◽  
Mutation Status ◽  
Expression Levels ◽  
Lentiviral Transduction ◽  
Knock Down ◽  
Healthy Donors ◽  
Acute Myeloid

Abstract Introduction FLT3 mutations consisting of internal tandem duplications (ITDs) occur in about 30% of patients with acute myeloid leukemia (AML) and are associated with poor prognosis. FLT3-ITD mediates proliferation and survival, blocks myeloid differentiation, and induces leukemic transformation in hematopoietic stem and progenitor cells (HSPCs). CD97 belongs to a subgroup of adhesion GPCRs which are known to be expressed in lymphoid and myeloid cells as well as on solid tumors but nothing is described so far about the expression and regulation in human normal and malignant HSPCs. Therefore, we investigated a possible implication of CD97 in AML and an association to clinically important mutations. Methods We studied 292 samples from patients with de novo acute leukemia, comprising AML M0-2 (n=195), AML M3 (n=16), AML M4/5 (n=63), AML M6/7 (n=4) and c-ALL (n=14). A 4-color immunophenotypic measurement was performed using the following antibodies: CD34 PerCp5.5, CD117 FITC, CD97 APC, CD45 V500. FLT3-ITD and NPM1 mutations were detected as reported in detail previously (Thiede C et al. Blood 2002; Thiede C et al. Blood 2006). In three human AML cell lines, MV4-11, EOL-1 and OCI-AML3, which display a specific FLT3 and NMP1 mutation status, we investigated the mRNA and protein expression levels of CD97 and a possible influence of the protein kinase inhibitors PKC412 (Midostaurin) and SU5614. CD97 knock-down in MV4-11 cells was achieved by lentiviral transduction of plko1.6/shRNACD97. CD34+ HSPCs were isolated from apheresis of healthy donors using MACS microbeads and were transduced with MFGS-FLT3-ITD-IRES-GFP (Jacobi A et al. Exp Hematol 2010). Results Compared to bone marrow blasts from, healthy donors (n=10), we detected significantly higher CD97 expression levels (mean fluorescence intensity, MFI) in 144 AML samples (49%). In detail, the CD97 expression could be observed in 40% out of cases with M0-2, 100% of cases with M3, 59% of patients with M4/5, 75% of M6/7 and 71% of the c-ALL cases, respectively. Of note, higher CD97 expression was accompanied by a significantly higher BM blast count (75% vs. 53%, p<0.001) and a lower Hb (5.9 vs. 6.5, p=0.02). Interestingly, elevated CD97 expression was associated with mutations in NPM1 (44% vs. 19%, p=0.002) and FLT3 genes (43% vs. 10%, p<0.0001) as well as lower CD34 (52% vs. 83%, p<0.0001) and HLA-DR expression (79% vs. 96%, p<0.0001). Quantitative real-time PCR analysis of AML cell lines with or without FLT3-ITD or NPM1 mutation revealed higher CD97 mRNA levels in cells carrying this mutation, as MV4-11 and OCI-AML3, compared to normal CD34+ HSPCs or EOL-1 cells, respectively. This result was confirmed at the protein level by flow cytometry. Treatment of MV4-11 cells with 0.5µM of the small molecule inhibitor PKC412 significantly decreased the CD97 expression. Another more specific FLT3 inhibitor SU5614 resulted in an even more decreased CD97 expression. In contrast, the low CD97 expression levels in EOL-1 cells and normal HSPCs were not affected by these inhibitors. Interestingly, induction of a leukemic phenotype in normal HSPCs by lentiviral transduction of FLT3-ITD also activated the CD97 expression confirming an association of the molecules. Knock-down of CD97 expression in MV4-11 cells by lentiviral transduction of shRNA constructs had no effect on the viability and proliferation but resulted in decreased spontaneous migration potential as well as inhibited adhesion to a mesenchymal stromal cell layer. This suggests a modulation of the bone marrow microenvironment by leukemic cells probably by interactions of CD97 with integrins expressed by stromal cells. Conclusions Our data provide evidence that the expression of CD97 is linked to the malignant phenotype of AML cells and may therefore serve as diagnostic and therapeutic target. Disclosures No relevant conflicts of interest to declare.

scholarly journals Synergistic Combination Activity of the Novel GSPT1 Degrader CC-90009 in Acute Myeloid Leukemia Models

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 3330-3330
Author(s):  
Daniel W. Pierce ◽  
Tsun-Wen Sheena Yao ◽  
Emily Pace ◽  
Hongbin Wang ◽  
Pierre Flandin-Blety ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Acute Myeloid Leukemia ◽  
Cell Lines ◽  
High Throughput ◽  
Myeloid Leukemia ◽  
Publicly Traded ◽  
Pdx Model ◽  
Flt3 Inhibitor ◽  
Healthy Donors ◽  
Acute Myeloid

Abstract Introduction: CC-90009 is a novel cereblon E3 ligase modulator (CELMoD ®) agent that is a first-in-class degrader of translation termination factor G1 to S phase transition 1 (GSPT1). CC-90009 has demonstrated antileukemic activity as a single agent and is currently under investigation in patients with acute myeloid leukemia (AML; NCT02848001). Treatment with CC-90009 led to rapid reductions in peripheral and bone marrow blasts, and demonstrated preliminary promising efficacy, including several complete remissions, in patients with relapsed or refractory AML. Here, we describe the identification and preclinical activity of select anti-AML agents as potential combination partners of CC-90009 to further improve its efficacy and therapeutic index. Based on these results, the combination activity of CC-90009 with venetoclax (VEN)/azacitidine (AZA) is being evaluated in a phase 1/2 trial in patients with AML (NCT04336982). Methods: A high-throughput cell viability screen was performed to identify synergistic partners of CC-90009. AML cell lines (HL-60, HNT-34, KG-1, ML-2, NOMO-1, MOLM-13, MV4-11, F-36P, OCI-AML2, OCI-AML3) were treated with CC-90009 in combination with &gt; 70 compounds, including standard anti-AML agents, tyrosine kinase inhibitors (TKIs), unfolded protein response inducers, transcription inhibitors, and epigenetic agents. MOLM-13 and MV4-11 are fms-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) cell lines. Hits were validated in a colony formation (CF) assay using primary AML cells and bone marrow mononuclear cells (BMMC) from healthy donors. Synergy of the combination partners with CC-90009 was further assessed in AML patient-derived xenograft (PDX) models. Synergy between the isocitrate dehydrogenase 2 (IDH2) inhibitor enasidenib and CC-90009 was evaluated in a TF-1 erythroleukemia cell line overexpressing IDH2 R140Q mutant, and an IDH2 R140Q PDX model, AM7577. Results: Our high-throughput combination screen revealed multiple TKIs, epigenetic agents, and pro-apoptotic agents as potential combination partners of CC-90009 in AML cell lines. FLT3 inhibitors, including sunitinib, pexidartinib, midostaurin, lestaurtinib, crenolanib, and gilteritinib, synergized with CC-90009 to reduce viability in FLT3-ITD AML cell lines MV4-11 and MOLM-13. Similarly, the B-cell lymphoma 2 (BCL2) inhibitor VEN potentiated CC-90009-induced apoptosis and accelerated cell-autonomous killing. Reduction in levels of MCL-1, an anti-apoptotic factor, by CC-90009 most likely contributed to the synergy with VEN. We prioritized the evaluation of FLT3, BCL2, and IDH2 inhibitors as partners of CC-90009. In CF assays, midostaurin enhanced the inhibitory effect of CC-90009 in primary AML cells, without augmenting the effect of CC-90009 in CD34+ BMMC from healthy donors. Similarly, VEN enhanced the reduction in CF by CC-90009 in AML patient-derived BMMC without exacerbating the decrease in CF by CC-90009 in BMMC from healthy donors. We characterized FLT3 inhibitor/CC-90009 and BCL2 inhibitor/AZA/CC-90009 combinations in a FLT3-ITD PDX murine model, PDX1. The FLT3 inhibitor quizartinib significantly prolonged survival when combined with CC-90009 compared with either agent alone (P &lt; 0.001). Similarly, VEN/AZA/CC-90009 combination markedly extended survival compared with single agents or VEN/AZA doublets (P &lt; 0.001). The synergy between CC-90009 and epigenetic modulators was validated and further characterized in customized cell differentiation assays. Addition of CC-90009 to enasidenib, a mutant IDH2 inhibitor, enhanced differentiation and killing of CD34+ stem and progenitor cells, and increased differentiated CD235a+ erythroblasts, compared with enasidenib alone in a TF-1 cell line overexpressing IDH2 R140Q. Enasidenib/CC-90009 combination treatment reduced CD45+ malignant populations and increased differentiated CD14+ cells, leading to significantly prolonged animal survival in an IDH2 R140Q PDX model, AM7577, compared with either agent alone (P &lt; 0.0001). Conclusion: Using a high-throughput combination screen, we identified rational combination partners that synergize with CC-90009 in in vitro and in vivo AML models. Collectively, these results support the clinical evaluation of CC-90009 in combination with FLT3, BCL2, and IDH2 inhibitors to further improve treatment outcomes for patients with AML. Disclosures Pierce: Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Yao: Bristol Myers Squibb: Consultancy, Current equity holder in publicly-traded company, Ended employment in the past 24 months, Research Funding. Pace: Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company, Patents & Royalties. Wang: Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Flandin-Blety: Bristol Myers Squibb: Current Employment. Benitez: Bristol Myers Squibb: Current Employment. Guarinos: Bristol Myers Squibb: Current Employment. Hoffmann: Bristol Myers Squibb: Current Employment. Carrancio: Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Pourdehnad: Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company, Patents & Royalties.

scholarly journals A proteomic approach to understand the clinical significance of acute myeloid leukemia-derived extracellular vesicles reflecting essential characteristics of leukemia

2020 ◽  
pp. mcp.RA120.002169
Author(s):  
Ka-Won Kang ◽  
Hyoseon Kim ◽  
Woojune Hur ◽  
Jik-han Jung ◽  
Su Jin Jeong ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Cell Lines ◽  
Myeloid Leukemia ◽  
Extracellular Vesicle ◽  
The Cancer Genome Atlas ◽  
Enzyme Linked Immunosorbent Assay ◽  
Expression Levels ◽  
Proteomic Approach ◽  
Cancer Genome Atlas ◽  
Acute Myeloid

Extracellular vesicle (EV) proteins from acute myeloid leukemia (AML) cell lines were analyzed using mass spectrometry. The analyses identified 2450 proteins, including 461 differentially expressed proteins (290 upregulated and 171 downregulated). CD53 and CD47 were upregulated and were selected as candidate biomarkers. The association between survival of patients with AML and the expression levels of CD53 and CD47 at diagnosis was analyzed using mRNA expression data from The Cancer Genome Atlas database. Patients with higher expression levels showed significantly inferior survival than those with lower expression levels. Enzyme-linked immunosorbent assay results of the expression levels of CD53 and CD47 from EVs in the bone marrow of patients with AML at diagnosis and at the time of complete remission with induction chemotherapy revealed that patients with downregulated CD53 and CD47 expression appeared to relapse less frequently. Network model analysis of EV proteins revealed several upregulated kinases, including LYN, CSNK2A1, SYK, CSK, and PTK2B. The potential cytotoxicity of several clinically applicable drugs that inhibit these kinases was tested in AML cell lines. The drugs lowered the viability of AML cells. The collective data suggest that AML-derived EVs could reflect essential leukemia biology.

Mesenchimal Stroma Cells From Patients with Myelodysplastic Syndrome and Acute Myeloid Leukemia Show Distinct Cytogenetic and DNA-Mutation Data as Compared with Bone Marrow Leukemic Blasts.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4697-4697
Author(s):  
Olga Blau ◽  
Wolf-Karsten Hofmann ◽  
Claudia D Baldus ◽  
Gundula Thiel ◽  
Florian Nolte ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Conflicts Of Interest ◽  
Control Analysis ◽  
Npm1 Mutation ◽  
Dna Mutation ◽  
Healthy Donors ◽  
Acute Myeloid

Abstract Abstract 4697 Bone marrow mesenchymal stroma cells (BMSC) are key components of the hematopoietic microenvironment. BMSC from patients with acute myeloid leukemia (AML) and myelodisplasic syndrome (MDS) display functional and quantitative alterations. To gain insight into these questions, we carried out cytogenetic analyses, FISH, FLT3 and NPM1 mutation examinations of both hematopoietic (HC) and BMSC derived from 53 AML and 54 MDS patients and 35 healthy donors after in vitro culture expansion. Clonal chromosomal aberrations were detectable in BMSC of 12% of patients. Using FISH we have assume that cytogenetic markers in BMSC were always distinct as the aberrations in HC from the same individual. 17% and 12% of AML patients showed FLT3 and NPM1 mutations in HC, respectively. In BMSC, we could not detect mutations of NPM1 and FLT3, independent from the mutation status of HC. For control analysis, BMSC cultures from 35 healthy donors were prepared under the same conditions. BMSC from healthy donors did show normal diploid karyotypes and absence of specific DNA-mutations of NPM1 and FLT3. Our data indicate that BMSC from MDS and AML patients are not a part of malignant clone and characterized by genetic aberrations. Lack of aberrations as detected in HC and appearance of novel clonal rearrangements in BMSC may suggest enhanced genetic susceptibility and potential involvement of BMSC in the pathogenesis of MDS and AML. Disclosures: No relevant conflicts of interest to declare.

Characterization of Extramedullary Acute Myeloid Leukemia – Results of the AML96 Trial

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 2154-2154
Author(s):  
Friedrich Stölzel ◽  
Christoph Röllig ◽  
Michael Kramer ◽  
Brigitte Mohr ◽  
Uta Oelschlägel ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Acute Myeloid Leukemia ◽  
Induction Chemotherapy ◽  
Myeloid Leukemia ◽  
The Body ◽  
Hematopoietic Stem ◽  
Npm1 Mutation ◽  
Mutation Status ◽  
The Impact ◽  
Acute Myeloid

Abstract Abstract 2154 Background: Myeloid Sarcoma (MS) is defined as an extramedullary mass composed of myeloid blasts occurring at an anatomical site other than the bone marrow. Furthermore, the term extramedullary manifestation (EM) is applied if it accompanies overt acute myeloid leukemia (AML) and represents non-effacing tissue infiltration. EM is reported to correspond often to the skin but can affect almost every site of the body. The prognosis of MS or EM has been discussed controversially in the past. EM at diagnosis of AML is generally thought to be a rare event. However, data defining the prevalence of EM at diagnosis of AML and its prognostic value are missing. The aim of this analysis was to provide data for estimating the prevalence of EM at diagnosis of AML and to determine its relevance by including clinical and laboratory data from patients being treated in the prospective AML96 trial of the Study Alliance Leukemia (SAL) study group. Patients and Methods: A total of 326 patients with AML (age 17 – 83 years) and EM were treated within the AML96 trial with a median follow up of 8.8 years (95% CI, 8.4 to 9.3 years). All patients received double induction chemotherapy. Consolidation therapy contained high-dose cytosine arabinoside and for patients ≤ 60 years of age the option of autologous or allogeneic hematopoietic stem cell transplantation (HSCT). Logistic regression analyses were used to identify prognostic variables for CR rates. The method of Kaplan-Meier was used to estimate OS and EFS. Confidence interval (CI) estimation for the survival curves was based on the cumulative hazard function using the Greenwood's formula for the SE estimation. Survival distributions were compared using the log rank test. Results: 17% of the AML patients entered into the AML96 trial were diagnosed with EM. In 313 of the 326 patients (96%) EM was evident at diagnosis. The majority of patients with EM were diagnosed with de novo AML (84%, n=273), whereas gingival infiltration (51%, n=166) displayed the main EM of AML with CNS involvement being less common (4%, n=14). The majority of patients had a cytogenetic intermediate risk profile (71%, n=221) with a total of 172 patients (56%) harboring a normal karyotype. Patients with EM had a statistically significant lower median CD34-positivity of bone marrow blasts, higher percentage of FAB subtypes M4 and M5, higher WBC counts and LDH at diagnosis and higher percentage of NPM1 mutations compared to those patients without EM (all p<.001). When comparing achievement of CR between patients with EM to patients without EM, no statistical difference between these two groups was observed. Analysis according to the NPM1/FLT3-ITD mutation status revealed highest 5-year-OS (37%, 95% CI: .24 - .508) and 5-year-EFS (36%, 95% CI: .224 - .448) in the NPM1-mut/FLT3-wt group and lowest 5-year-OS (12%, 95% CI: 0 - .261) and 5-year-EFS (4%, 95% CI: 0 - .124) in the NPM1-wt/FLT3-ITD group, p=.007 and p=.001, respectively. Of the 49 relapsed patients with EM who had a NPM1-mutation at diagnosis 48 deceased despite of intensified relapse therapies. Conclusions: This analysis represents the largest study so far investigating the impact of EM AML. Patients with EM AML have distinct differences from AML patients without EM regarding their clinical and molecular characteristics at diagnosis. However these differences do not translate into differences in response to induction chemotherapy. Compared to patients without EM, survival analysis revealed differences according to the NPM1/FLT3-ITD mutation status which is also described for patients without EM AML. However, the prognosis for patients with EM who harbor a mutated NPM1 the prognosis at relapse seems to be dismal. Disclosures: No relevant conflicts of interest to declare.

Identifying Small Molecules That Overcome HoxA9-Mediated Differentiation Arrest in Acute Myeloid Leukemia

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 3513-3513
Author(s):  
David B. Sykes ◽  
Mark K Haynes ◽  
Nicola Tolliday ◽  
Anna Waller ◽  
Julien M Cobert ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
Acute Myeloid Leukemia ◽  
Small Molecules ◽  
Cell Line ◽  
Cell Lines ◽  
Myeloid Leukemia ◽  
Myeloid Differentiation ◽  
Prostacyclin Receptor ◽  
Acute Myeloid

Abstract Abstract 3513 AML in adults is a devastating disease with a 5-year survival rate of 25%. We lack new treatments for AML, and the chemotherapy standard of care remains unchanged in thirty years. One success story in the treatment of AML has been the discovery of drugs that trigger the differentiation of leukemic blasts in the small subset of patients with acute promyelocytic leukemia. However, differentiation therapy is unfortunately not available for the remaining 90% of non-APL acute myeloid leukemia patients. Understanding and targeting the mechanism of differentiation arrest in AML has been under investigation for more than four decades. There is growing evidence to support the role of the homeobox transcription factors in normal hematopoietic differentiation as well as malignant hematopoiesis. The persistent, and inappropriate, expression of the homeobox gene HoxA9 has been described in the majority of acute myeloid leukemias. This implicates HoxA9 dysregulation as a common pathway of differentiation arrest in myeloid leukemias and suggests that by understanding and targeting this pathway, one might be able to overcome differentiation arrest. In cultures of primary murine bone marrow, constitutive expression of HoxA9 blocks myeloid differentiation and results in the outgrowth of immature myeloid cell lines. The mechanism by which HoxA9 causes differentiation arrest is not known and no compounds exist that inhibit HoxA9. We developed a murine cell line model in which the cells were blocked in differentiation by a conditional version of HoxA9. In this system, an estrogen-dependent ER-HoxA9 protein was generated by fusion with the estrogen receptor hormone-binding domain. When expressed in cultures of primary murine bone marrow, immortalized myeloblast cell lines can grow indefinitely in the presence of stem cell factor and beta-estradiol. Upon removal of beta-estradiol, and inactivation of HoxA9, these cell lines undergo synchronous and terminal myeloid differentiation. We took advantage of an available transgenic mouse model in which GFP was expressed downstream of the lysozyme promoter, a promoter expressed only in mature neutrophils and macrophages. Cell lines derived from the bone marrow of this lysozyme-GFP mouse were GFP-negative at baseline and brightly GFP-positive upon differentiation. In this manner, we generated a cell line with a built-in reporter of differentiation. These cells formed the basis of a high-throughput screen in which cells were incubated with small molecules for a period of four days in 384-well plate format. The cells were assayed by multi-parameter flow cytometry to assess for toxicity and differentiation. Compounds that triggered green fluorescence were scored as “HITS” and their pro-differentiation effects confirmed by analysis of morphology and cell surface markers. Given the availability of cells and the simple and reliable assay, we performed both a pilot screen of small molecules at The Broad Institute as well as an extensive screen of the NIH Molecular Libraries Small Molecule Repository. The screen of more than 350,000 small molecules was carried out in collaboration with the University of New Mexico Center for Molecular Discovery. We have identified one lead class of compounds - prostacyclin agonists – capable of promoting myeloid differentiation in this cell line model of AML. Using a parallel cell line derived from a prostacyclin receptor knock-out mouse, we confirmed that activity was due to signaling through the prostacyclin receptor. The role of prostacyclin signaling in myeloid differentiation has not been previously described. Analysis of gene expression demonstrated that the expression of the prostacyclin receptor is seen in ∼60% of in primary human AML samples. This is a potentially exciting finding as prostacyclin agonists (e.g. treprostinil) are clinically relevant as well as FDA-approved. Their potential role in the treatment of acute myeloid leukemia is unknown. Here we present the details of our high-throughput flow cytometry system and preliminary identification of pro-differentiation agents in AML. If successful, we anticipate that one of these small molecules may offer insight into a mechanism for overcoming differentiation arrest, and may also translate into a novel, clinically relevant treatment for acute myeloid leukemia. Disclosures: Sklar: IntelliCyt: Founder of IntelliCyt, the company that sells the HyperCyt high-throughput flow cytometry system. Other. Zon:Fate Therapeutics: Founder Other.

Inhibition Of LSD1 As a Therapeutic Strategy For The Treatment Of Acute Myeloid Leukemia

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3964-3964 ◽  
Author(s):  
Ryan G. Kruger ◽  
Helai Mohammad ◽  
Kimberly Smitheman ◽  
Monica Cusan ◽  
Yan Liu ◽  
...  
Keyword(s):  
Gene Expression ◽  
Bone Marrow ◽  
Acute Myeloid Leukemia ◽  
Cell Surface ◽  
Growth Inhibition ◽  
Cell Lines ◽  
Myeloid Leukemia ◽  
Stem Cell Differentiation ◽  
Ethical Review Process ◽  
Acute Myeloid

Abstract Lysine specific demethylase 1 (LSD1) is a histone H3K4me1/2 demethylase found in various transcriptional co-repressor complexes. These complexes include Histone Deacetylases (HDAC1/2) and Co-Repressor for Element-1-Silencing Transcription factor (CoREST). LSD1 mediated H3K4 demethylation can result in a repressive chromatin environment that silences gene expression. LSD1 has been shown to play a role in development in various contexts. LSD1 can interact with pluripotency factors in human embryonic stem cells and is important for decommissioning enhancers in stem cell differentiation. Beyond embryonic settings, LSD1 is also critical for hematopoietic differentiation. LSD1 is overexpressed in multiple cancer types and recent studies suggest inhibition of LSD1 reactivates the all-trans retinoic acid receptor pathway in acute myeloid leukemia (AML). These studies implicate LSD1 as a key regulator of the epigenome that modulates gene expression through post-translational modification of histones and through its presence in transcriptional complexes. The current study describes the anti-tumor effects of a novel LSD1 inhibitor (GSK2879552) in AML. GSK2879552 is a potent, selective, mechanism-based, irreversible inhibitor of LSD1. Screening of over 150 cancer cell lines revealed that AML cells have a unique requirement for LSD1. While LSD1 inhibition did not affect the global levels of H3K4me1 or H3K4me2, local changes in these histone marks were observed near transcriptional start sites of putative LSD1 target genes. This increase in the transcriptionally activating histone modification correlated with a dose dependent increase in gene expression. Treatment with GSK2879552 promoted the expression of cell surface markers, including CD11b and CD86, associated with a differentiated immunophenotype in 12 of 13 AML cell lines. For example, in SKM-1 cells, increases in cell surface expression of CD86 and CD11b occurred after as early as one day of treatment with EC50 values of 13 and 7 nM respectively. In a separate study using an MV-4-11 engraftment model, increases in CD86 and CD11b were observed as early as 8 hours post dosing. GSK2879552 treatment resulted in a potent anti-proliferative growth effect in 19 of 25 AML cell lines (average EC50 = 38 nM), representing a range of AML subtypes. Potent growth inhibition was also observed on AML blast colony forming ability in 4 out of 5 bone marrow samples derived from primary AML patient samples (average EC50 = 205 nM). The effects of LSD1 inhibition were further characterized in an in vivo mouse model of AML induced by transduction of mouse hematopoietic progenitor cells with a retrovirus encoding MLL-AF9 and GFP. Primary AML cells were transplanted into a cohort of secondary recipient mice and upon engraftment, the mice were treated for 17 days. After 17 days of treatment, control treated mice had 80% GFP+ cells in the bone marrow whereas treated mice possessed 2.8% GFP positive cells (p<0.012). The percentage of GFP+ cells continued to decrease to 1.8% by 1-week post therapy. Remarkably, in a preliminary assessment for survival, control-treated mice succumbed to AML by 28 days post transplant, while treated mice showed prolonged survival. Together, these data demonstrate that pharmacological inhibition of LSD1 may provide a promising treatment for AML by promoting differentiation and subsequent growth inhibition of AML blasts. GSK2879552 is currently in late preclinical development and clinical trials are anticipated to start in 2014. All studies were conducted in accordance with the GSK Policy on the Care, Welfare and Treatment of Laboratory Animals and were reviewed the Institutional Animal Care and Use Committee either at GSK or by the ethical review process at the institution where the work was performed. Disclosures: Kruger: GlaxoSmithKline Pharmaceuticals: Employment. Mohammad:GlaxoSmithKline Pharmaceuticals: Employment. Smitheman:GlaxoSmithKline Pharmaceuticals: Employment. Liu:GlaxoSmithKline Pharmaceuticals: Employment. Pappalardi:GlaxoSmithKline Pharmaceuticals: Employment. Federowicz:GlaxoSmithKline Pharmaceuticals: Employment. Van Aller:GlaxoSmithKline Pharmaceuticals: Employment. Kasparec:GlaxoSmithKline Pharmaceuticals: Employment. Tian:GlaxoSmithKline Pharmaceuticals: Employment. Suarez:GlaxoSmithKline Pharmaceuticals: Employment. Rouse:GlaxoSmithKline Pharmaceuticals: Employment. Schneck:GlaxoSmithKline Pharmaceuticals: Employment. Carson:GlaxoSmithKline Pharmaceuticals: Employment. McDevitt:GlaxoSmithKline Pharmaceuticals: Employment. Ho:GlaxoSmithKline Pharmaceuticals: Employment. McHugh:GlaxoSmithKline Pharmaceuticals: Employment. Miller:GlaxoSmithKline Pharmaceuticals: Employment. Johnson:GlaxoSmithKline Pharmaceuticals: Employment. Armstrong:Epizyme Inc.: Has consulted for Epizyme Inc. Other. Tummino:GlaxoSmithKline Pharmaceuticals: Employment.

Molecular Mechanism Of Regulation Of Extramedullary Infiltration In AML1/ETO Positive Acute Myeloid Leukemia By APP/ERK/MMP-2

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3769-3769
Author(s):  
Guopan Yu ◽  
Fan Yi Meng ◽  
Ling Jiang ◽  
Changxin Yin ◽  
Zhixiang Wang ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Acute Myeloid Leukemia ◽  
Molecular Mechanism ◽  
Myeloid Leukemia ◽  
High Expression ◽  
Control Group ◽  
Expression Levels ◽  
High Expression Group ◽  
App Gene ◽  
Acute Myeloid

Abstract Amyloid precursor protein (APP) has been reported to be highly expressed in AML1/ETO positive acute myeloid leukemia (AML1/ETO+ AML), and we found it express even higher in those with extramedullary infiltration in our previous study. But it’s still unknown what role APP plays and how it works in AML1/ETO+ AML. This study was designed to investigate the effect of APP gene on the prognosis and its molecular mechanism of extramedullary infiltration in the patients with AML1/ETO+ AML. 44 cases of AML1/ETO+ AML patients with median age of 29 years old, who were admitted to our hospital from February, 2006 to February, 2012 and made the diagnosis according to WHO2008 diagnosis standard, and had completed conventional induction, consolidation and intensive therapy, were investigated in this study. They were divided into high expression group (n=22) and low one (n=22) according to APP mRNA median expression level from bone marrow cells before the first chemotherapy by QRT-PCR. Some of bone marrow samples were checked by Western Blot, and 5 biopsy specimens from extramedullary infiltration were tested by APP antibody immunohistochemistry staining. Incidence of extramedullary leukemia (EML), complete response (CR), overall survival (OS), and recurrence free survival (RFS) was differentiated between the two groups. Differences of cell ultrastructure, migration, proliferation, apoptosis and expression of ERK, MMP-2, MMP-9 and CXCR4 were studied on Kasumi-1 cell line between wild, negative control (NC) and si-APP group in which the expression levels of APP gene were down regulated with application of siRNA technology.Çå The incidence of EML was significantly different (45.5% versus 9.1%) in the two groups (P=0.007) and it was positively correlative with the expression levels of APP mRNA (rp=0.435, P=0.004). Extramedullary infiltration site also showed high expression of APP by immunohistochemistry, while the control group was negative. Not only CR rate after two courses of chemotherapy, but also OS and RFS with median follow-up of 28(4-70) months, of high expression group was all significantly lower than that of low expression group (Table 1). Compared with the wild and NC group, cell apoptosis of si-APP group was significantly increased (12.33 ± 0.75 vs 19.80 ± 1.51, P=0.000); the number of microvilli on the surface of the cell membrane significantly reduced; the ability of the cell migration by Tanswell chamber migration assay significantly decreased (P=0.004); and expression of P-ERK, c-MYC, MMP-2 decreased significantly which was confirmed by ERK and c-MYC blocker treatment (Figure 1). In sum, incidence of EML is significantly higher and the prognosis is poor in the patients with AML1/ETO+ AML with high expression of APP gene. We first describe that APP gene may mediate AML1/ETO+ leukemia cells in the development of extramedullary infiltration by up-regulation of the ERK/MMP-2 pathway. Disclosures: No relevant conflicts of interest to declare.

scholarly journals High Expression of Myocyte Enhancer Factor 2C (MEF2C) Is Associated with Adverse Risk Features and Poor Outcome in Pediatric Acute Myeloid Leukemia: A Report from the Children's Oncology Group

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 2570-2570
Author(s):  
George S. Laszlo ◽  
Todd A. Alonzo ◽  
Chelsea J. Gudgeon ◽  
Kimberly H. Harrington ◽  
Alex Kentsis ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Overall Survival ◽  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Research Funding ◽  
Event Free Survival ◽  
Free Survival ◽  
Expression Levels ◽  
Acute Myeloid ◽  
Enhancer Factor

Abstract Background: Myocyte enhancer factor 2C (MEF2C) was initially identified as essential transcription factor for cardiac muscle development. However, subsequent studies have indicated that MEF2C plays a much broader biological role, including in the normal hematopoietic system. Recent studies have now identified MEF2C as cooperating oncogene in acute myeloid leukemia (AML) and suggested a contribution to the aggressive nature of at least some subtypes of AML. These findings raised the possibility that MEF2C could serve as marker of poor-risk disease and, therefore, have prognostic significance in AML. To test this hypothesis, we retrospectively quantified MEF2C expression in participants of the AAML0531 trial and correlated expression levels with disease characteristics and clinical outcome. Patients and Methods: AAML0531 (NCT00372593) was a multicenter phase 3 study that determined the addition of gemtuzumab ozogamicin to intensive chemotherapy among 1,022 eligible patients aged <30 yearswith newly diagnosed de novo non-APL AML, excluding those with bone marrow failure syndromes, juvenile myelomonocytic leukemia, or Down syndrome (if ≤3 years of age) between 2006 and 2010. Cryopreserved pretreatment ("diagnostic") specimens from patients enrolled on AAML0531 who consented to the biology studies and had bone marrow samples were available were included in this study. Total RNA from unsorted specimens was extracted, quantified, and subjected to quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) using TaqMan primers to determine expression of MEF2C and, for normalization, the housekeeping gene, β-glucuronidase (GUSB). Patient samples were run in duplicate, and the ΔΔCT method quantified as 2(-ΔΔCT) was used to determine the expression levels of MEF2C relative to GUSB. Results: In all 751 available patient specimens, MEF2C mRNA was detectable and varied >3,000-fold relative to GUSB (0.0091-29.1272 [median: 0.7978]). Patients with the highest relative MEF2C expression (4th quartile) less likely achieved a complete remission after one course of chemotherapy than the other patients (67% vs. 78%, P=0.005). They also had an inferior overall survival (P=0.014; at 5 years: 55±8% vs. 67±4%), inferior event-free survival (P<0.001; at 5 years: 38±7% vs. 54±4%), and higher relapse risk than patients within the lower 3 quartiles of MEF2C expression (P<0.001; at 5 years: 53±9% vs. 35±5%). Of note, exploratory multiple cutpoint analyses for overall and event-free survival indicated that the most statistically significant results were centered around the Q4 cutpoint region, supporting our approach of comparing patients with the highest quartile of relative MEF2C expression with those having lower relative MEF2C expression. Importantly, MEF2C expression was strongly associated with cytogenetic and molecular abnormalities. Specifically, patients with high MEF2C expression less likely had CBF translocations (inv(16): P=0.007, and t(8;21): P<0.001) or normal karyotype AML (P<0.001); conversely, they were more likely to have leukemia with monosomy 7 (P<0.001) and abnormalities involving 11q23 (P<0.001). Furthermore, patients with high MEF2C less likely had a FLT3/ITD (P =0.018) or a mutation in either NPM1 (P=0.010) or CEBPA (P =0.002). Consistently, patients with high MEF2C expression less likely had low-risk disease (16% vs. 46%, P<0.001) and more likely had standard-risk disease (68% vs. 42%, P <0.001) than those with lower MEF2C expression. Indeed, after adjustment for disease risk, age, FAB category, and treatment arm, high MEF2C expression was no longer statistically significantly associated with inferior overall survival (hazard ratio [HR]=0.99 [95% confidence interval: 0.72-1.36], P=0.929), inferior event-free survival (HR: 1.14 [0.86-1.49], P=0.365), or higher relapse risk (HR: 1.32 [0.91-1.92], P=0.137), suggesting that MEF2C cooperates with additional pathogenic abnormalities. Conclusion: High MEF2C expression identifies a subset of AML patients with adverse-risk disease features and poor outcome. These findings provide the rationale for therapeutic targeting of MEF2C transcriptional activation in AML. Disclosures Walter: AstraZeneca, Inc.: Consultancy; Covagen AG: Consultancy; Seattle Genetics, Inc.: Research Funding; Amgen, Inc.: Research Funding; Pfizer, Inc.: Consultancy; Amphivena Therapeutics, Inc.: Consultancy, Research Funding.

scholarly journals Stromal CYR61 Confers Resistance to Mitoxantrone Via Spleen Tyrosine Kinase Activation in Human Acute Myeloid Leukemia

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 2228-2228
Author(s):  
Xin Long ◽  
Laszlo Perlaky ◽  
Tsz-Kwong Chris Man ◽  
Michele S. Redell
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
Acute Myeloid Leukemia ◽  
Cell Lines ◽  
Stromal Cells ◽  
Myeloid Leukemia ◽  
Stromal Cell ◽  
Chemotherapy Resistance ◽  
Induced Apoptosis ◽  
Acute Myeloid

Abstract Acute myeloid leukemia (AML) is a life-threatening bone marrow malignancy with a relapse rate near 50% in children, despite aggressive chemotherapy. Accumulating evidence shows that the bone marrow stromal environment protects a subset of leukemia cells and allows them to survive chemotherapy, eventually leading to recurrence. The factors that contribute to stroma-induced chemotherapy resistance are largely undetermined in AML. Our goal is to delineate the mechanisms underlying stroma-mediated chemotherapy resistance in human AML cells. We used two human bone marrow stromal cell lines, HS-5 and HS-27A, to study stroma-induced chemotherapy resistance. Both stromal cell lines are equally effective in protecting AML cell lines and primary samples from apoptosis induced by chemotherapy agents, including mitoxantrone, etoposide, and cytarabine. By gene expression profiling using the Affymetrix U133Plus 2 platform, we previously found that CYR61 was among the genes that were commonly upregulated in AML cells by both stromal cell lines. CYR61 is a secreted matricellular protein that is expressed at relatively low levels by AML cells, and at higher levels by stromal cells. CYR61 binds and activates integrins and enhances growth factor signaling in AML cells, and it has been associated with chemoresistance in other malignancies. Our current data provide functional evidence for a role for this protein in stroma-mediated chemoresistance in AML. First, we added anti-CYR61 neutralizing immunoglobulin (Ig), or control IgG, to AML-stromal co-cultures, treated with chemotherapy for 24 hours, and measured apoptosis with Annexin V staining and flow cytometry. In THP-1+HS-27A co-cultures treated with 50 nM mitoxantrone, the apoptosis rate was 33.0 ± 3.7% with anti-CYR61 Ig v. 16.3 ± 4.2% with control IgG; p=0.0015). Next, we knocked down CYR61 in the HS-5 and HS-27A stromal cell lines by lentiviral transduction of two individual shRNA constructs, and confirmed knockdown (KD) at the gene and protein levels for both cell lines. These CYR61-KD stromal cells provided significantly less protection for co-cultured AML cells treated with mitoxantrone, compared to stromal cells transduced with the non-silencing control. For example, the apoptosis rate for THP-1 cells co-cultured with CYR61-KD HS-27A cells was 10.8 ± 0.8%, compared to 6.8 ± 1.1% for THP-1 cells co-cultured with control HS-27A cells (p=0.02). Similar results were obtained with NB-4 AML cells. These results demonstrate that CYR61 contributes to stroma-mediated chemoresistance. CYR61 binds to integrin αvβ3 (Kireeva, et al, J. Biol. Chem., 1998, 273:3090), and this integrin activates spleen tyrosine kinase (Syk) (Miller, et al, Cancer Cell, 2013, 24:45). Using intracellular flow cytometry, we found that activated Syk (pSyk) increased in THP-1 and NB-4 cell lines, and in primary AML patient samples, upon exposure to control HS-27A cells. In primary samples, the mean fluorescence intensity (MFI) for pSyk averaged 11.7 ± 1.3 in co-culture v. 6.6 ± 0.6 for cells cultured alone (p=0.004, n=10). In contrast, pSyk did not significantly increase in AML cells co-cultured with CYR61-KD HS-27A cells (MFI for primary patient samples: 8.6 ± 0.8). This result implicates Syk as a downstream signaling mediator of CYR61. To determine the role of CYR61-induced Syk signaling in chemotherapy resistance, we treated AML-stromal cell co-cultures with 3 uM R406, a potent Syk inhibitor, or DMSO, then added 300 nM mitoxantrone, and measured apoptosis after 24 hours. In AML cells co-cultured with control HS-27A cells, mitoxantrone-induced apoptosis was significantly increased by Syk inhibition (THP-1 cells: 13.7 ± 0.7% with R406 v. 10.0 ± 0.3% with DMSO, p<0.05), consistent with reduced chemoresistance. Notably, R406 did not further increase mitoxantrone-induced apoptosis in AML cells co-cultured with CYR61-KD HS-27A stromal cells (THP-1 cells: 15.7 ± 0.2% with R406 v. 16.9 ± 0.4% with DMSO). Similar results were seen with NB-4 cells, as well. These results support the notion that CYR61 signals through the integrin-Syk pathway to protect AML cells from chemotherapy. Therefore, the CYR61 - integrin - Syk pathway may be a potential therapeutic target for overcoming stroma-induced chemotherapy resistance in AML. Disclosures No relevant conflicts of interest to declare.

Evidence of increased angiogenesis in patients with acute myeloid leukemia

Blood ◽  
2000 ◽  
Vol 95 (1) ◽  
pp. 309-313 ◽  
Author(s):  
Jerry W. Hussong ◽  
George M. Rodgers ◽  
Paul J. Shami
Keyword(s):  
Bone Marrow ◽  
Acute Myeloid Leukemia ◽  
Growth Factor ◽  
Cell Lines ◽  
Myeloid Leukemia ◽  
Inhibition Of Angiogenesis ◽  
Novel Strategy ◽  
Von Willebrand ◽  
Endothelial Growth Factor ◽  
Acute Myeloid

Abstract Angiogenesis plays a key role in solid tumor growth. The purpose of this work was to study angiogenesis in acute myeloid leukemia (AML). We stained bone marrow samples from 20 adult patients with untreated AML and 20 normal controls using endothelial cell markers (ULEX-E and von Willebrand factor [vWF]). The number of vessels per millimeter length of bone marrow core biopsy specimen was scored by light microscopy. Using ULEX-E staining, AML marrows had (average ± SEM) 8.3 ± 3.6 vessels/mm (range, 3.7-19.3), whereas normal marrows had 4.3 ± 1.8 vessels/mm (range, 1.6-7.9). A similar difference was noted using vWF staining (8.6 ± 3.0 vessels/mm vs 4.9 ± 2.2 vessels/mm in AML vs normal bone marrows, respectively). The differences between the numbers of vessels/mm in AML and normal marrows were highly significant (P &lt; .0001 for both ULEX-E and vWF staining). When analyzed by FAB category, there was no difference in the average number of vessels/mm among the different subgroups of AML. Using reverse transcriptase polymerase chain reaction, we observed that the HL-60 and U937 human AML cell lines and 4 of 4 freshly isolated AML cells from untreated patients expressed mRNA for vascular endothelial growth factor (VEGF). Both cell lines as well as all fresh AML isolates tested expressed VEGF protein. Basic fibroblast growth factor was expressed only in HL-60 cells and in only 3 of 4 fresh AML samples. These observations suggest that angiogenesis may play a role in the pathogenesis of AML. Inhibition of angiogenesis could constitute a novel strategy for the treatment of AML. (Blood. 2000;95:309-313).

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