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

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.

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Identification of Sensitizing Targets to the Hypomethylating Agent 5-Azacytidine in Acute Myeloid Leukemia Cells Using RNAi-Based Functional Genomics Screening

Blood ◽

10.1182/blood.v112.11.2665.2665 ◽

2008 ◽

Vol 112 (11) ◽

pp. 2665-2665

Author(s):

Raoul Tibes ◽

Ashish Choudhary ◽

Amanda Henrichs ◽

Sadia Guled ◽

Irma Monzon ◽

...

Keyword(s):

Acute Myeloid Leukemia ◽

Growth Inhibition ◽

Cell Lines ◽

Myeloid Leukemia ◽

Statistical Significance ◽

Molecular Targets ◽

Leukemia Cells ◽

Hypomethylating Agents ◽

Acute Myeloid Leukemia Cells ◽

Acute Myeloid

Abstract • Hypomethylating agents like 5-Azacytidine (5Aza) have become an effective therapy for myelodysplastic syndromes (MDS) and show promise in acute myeloid leukemia (AML). In AML, complimentary mechanisms including epigenetic silencing of growth controlling genes, i.e. tumor suppressors, and activation of kinases contribute to malignant transformation. In order to enhance the therapeutic potential of epigenetic therapies, we developed a high-throughput RNA interference (HT-RNAi) platform for large-scale transient gene silencing in acute myeloid leukemia cells. This assay allows for the first time to individually silence hundreds or thousands of genes in combination with 5Aza to identify molecular targets whose inhibition enhances the anti-leukemic effect of hypomethylating agents. As part of assay development for HT-RNAi, ten AML cell lines were used to determine the median inhibitory concentration (IC50) of 5Aza for each AML cell lines. Furthermore, the ten cell lines were tested with a panel of cationic lipid transfection reagents at varying weight to volume (wt:vol) ratios to determine the optimal siRNA transfection conditions. Results from these studies identified two AML cell lines TF1 and ML4, which were advanced into kinome-epigenetic RNAi screens. Using a lipid-based method, cells were reverse transfected for 48hrs with 2 different siRNA sequences per gene targeting a total of 572 kinases. After 48hrs, 5Aza at the calculated IC25 was added for an additional 72 hrs and cell proliferation was measured using a luminescence-based assay. Data was background corrected and analyzed using the B-score method to report the strength and statistical significance of growth inhibition compared to controls. A B-score of <−2 indicates statistical significance with p<0.05 (>95% confidence); a B-score <−1.5 provides >87% confidence and was used as lowest cutoff given that screens are focused and contain validated siRNA to kinases. Analysis of two independent RNAi kinome screens, one in TF1 and the other in ML4, in combination with 5Aza, identified six and eleven kinases respectively whose silencing by two different siRNA sequences (2× coverage) potentiated the effects of 5Aza at B-score <−1.5. In ML4 cells 2 kinases were highly significant with a B-score for both siRNA <−2. Six kinases were common targets in both cell lines with significant growth inhibition at a B-score for both siRNA of at least <−1.5 making these kinases potential important modifiers of response to 5Aza. In summary, initial kinome RNAi screens in myeloid cells identified specific kinases as potential sensitizing targets to hypomethylating agents. Moreover, functional genomic RNAi screens provide a fast and attractive approach to identify molecular targets in AML for the rational development of combination therapies with hypomethylating agents as well as other drug classes.

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Deregulated Apoptotic Pathways Point to Effectiveness of IAP Inhibitor Therapy in Acute Myeloid Leukemia.

Blood ◽

10.1182/blood.v114.22.1275.1275 ◽

2009 ◽

Vol 114 (22) ◽

pp. 1275-1275

Author(s):

Sonja C Lück ◽

Annika C Russ ◽

Konstanze Döhner ◽

Ursula Botzenhardt ◽

Domagoj Vucic ◽

...

Keyword(s):

Gene Expression ◽

Acute Myeloid Leukemia ◽

Cell Line ◽

Cell Lines ◽

Myeloid Leukemia ◽

Gene Set Enrichment Analysis ◽

Core Binding Factor ◽

Binding Factor ◽

Acute Myeloid

Abstract Abstract 1275 Poster Board I-297 Core binding factor (CBF) leukemias, characterized by translocations t(8;21) or inv(16)/t(16;16) targeting the core binding factor, constitute acute myeloid leukemia (AML) subgroups with favorable prognosis. However, 40-50% of patients relapse, and the current classification system does not fully reflect the heterogeneity existing within the cytogenetic subgroups. Therefore, illuminating the biological mechanisms underlying these differences is important for an optimization of therapy. Previously, gene expression profiling (GEP) revealed two distinct CBF leukemia subgroups displaying significant outcome differences (Bullinger et al., Blood 2007). In order to further characterize these GEP defined CBF subgroups, we again used gene expression profiles to identify cell line models similar to the respective CBF cohorts. Treatment of these cell lines with cytarabine (araC) revealed a differential response to the drug as expected based on the expression patterns reflecting the CBF subgroups. In accordance, the cell lines resembling the inferior outcome CBF cohort (ME-1, MONO-MAC-1, OCI-AML2) were less sensitive to araC than those modeling the good prognostic subgroup (Kasumi-1, HEL, MV4-11). A previous gene set enrichment analysis had identified the pathways Caspase cascade in apoptosis and Role of mitochondria in apoptotic signaling among the most significant differentially regulated BioCarta pathways distinguishing the two CBF leukemia subgroups. Thus, we concluded that those pathways might be interesting targets for specific intervention, as deregulated apoptosis underlying the distinct subgroups should also result in a subgroup specific sensitivity to apoptotic stimuli. Therefore, we treated our model cell lines with the Smac mimetic BV6, which antagonizes inhibitor of apoptosis (IAP) proteins that are differentially expressed among our CBF cohorts. In general, sensitivity to BV6 treatment was higher in the cell lines corresponding to the subgroup with good outcome. Time-course experiments with the CBF leukemia cell line Kasumi-1 suggested a role for caspases in this response. Interestingly, combination treatment of araC and BV6 in Kasumi-1 showed a synergistic effect of these drugs, with the underlying mechanisms being currently further investigated. Based on the promising sensitivity to BV6 treatment in some cell lines, we next treated mononuclear cells (mostly leukemic blasts) derived from newly diagnosed AML patients with BV6 in vitro to evaluate BV6 potency in primary leukemia samples. Interestingly, in vitro BV6 treatment also discriminated AML cases into two distinct populations. Most patient samples were sensitive to BV6 monotherapy, but about one-third of cases were resistant even at higher BV6 dosage. GEP of BV6 sensitive patients (at 24h following either BV6 or DMSO treatment) provided insights into BV6-induced pathway alterations in the primary AML patient samples, which included apoptosis-related pathways. In contrast to the BV6 sensitive patients, GEP analyses of BV6 resistant cases revealed no differential regulation of apoptosis-related pathways in this cohort. These results provide evidence that targeting deregulated apoptosis pathways by Smac mimetics might represent a promising new therapeutic approach in AML and that GEP might be used to predict response to therapy, thereby enabling novel individual risk-adapted therapeutic approaches. Disclosures Vucic: Genentech, Inc.: Employment. Deshayes:Genentech, Inc.: Employment.

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Constitutive Activation of SHP2 Protein Tyrosine Phosphatase Cooperates with HoxA10 Overexpression for Progression to Acute Myeloid Leukemia in a Murine Model

Blood ◽

10.1182/blood.v112.11.752.752 ◽

2008 ◽

Vol 112 (11) ◽

pp. 752-752

Author(s):

Hao Wang ◽

Stephan Lindsey ◽

Iwona Konieczna ◽

Elizabeth Horvath ◽

Ling Bei ◽

...

Keyword(s):

Gene Expression ◽

Bone Marrow ◽

Acute Myeloid Leukemia ◽

Protein Tyrosine Phosphatase ◽

Myeloid Leukemia ◽

Tyrosine Phosphatase ◽

Post Translational Modification ◽

Protein Tyrosine ◽

Acute Myeloid ◽

Myeloid Progenitors

Abstract HOX genes encode highly conserved homeodomain (HD) transcription factors and are arranged in four groups (A–D). During definitive hematopoiesis, HOX gene expression is activated 3′ to 5′ through each group. Therefore, HOX1-4 are actively transcribed in hematopoietic stem cells and HOX7-11 in committed progenitors. Under normal conditions, HoxA7-11 expression decreases during CD34+ to CD34− maturation. Abnormal Hox expression is characteristic of several poor prognosis subtypes of Acute Myeloid Leukemia (AML) including AML with translocations or duplications of the MLL gene. In such leukemias, expression of HoxB3, B4 and A7-11 is sustained in CD34−CD38+ cells. In murine bone marrow transplantation experiments, expression of MLL fusion proteins, HoxA9 or HoxA10 induces a myeloproliferative disorder (MPD) characterized by increased neutrophils (PMN). Over time, the mice progress to AML with circulating myeloid blasts. These results suggest overexpression of HoxA9 or HoxA10 is adequate for MPD, but differentiation block (AML) requires additional lesions. We found that HoxA9 and HoxA10 proteins not only decrease in expression during the CD34+ to CD34− transition, but also are tyrosine phosphorylated. In additional studies, we found that HoxA10 tyrosine phosphorylation state is relevant for differentiation stage-specific target gene expression during myelopoiesis. HoxA10 represses genes encoding phagocyte effector proteins in undifferentiated myeloid cells. During myelopoiesis, phosphorylation of conserved HD-HoxA10 tyrosines decreases binding to these genes, permitting phenotypic and functional differentiation. HoxA10 activates transcription of the gene encoding Mkp2 (Dusp4) in myeloid progenitors. Decrease in HoxA10-binding to this gene as differentiation proceeds decreases transcription and renders the cells susceptible to Jnk induced apoptosis. Therefore, we hypothesized that genetic lesions which influence post translational modification might cooperate with HoxA10 overexpression to lead from MPD to AML. In myeloid progenitors, HoxA10 is maintained in a non-phosphorylated state by SHP2 protein tyrosine phosphatase. SHP2 activity decreases as differentiation proceeds. Activating mutations in SHP2 have been described in AML. We found that such activated SHP2 mutants dephosphorylate HoxA10 through out ex vivo myelopoiesis. Therefore, we investigated cooperation between these two leukemia associated abnormalities in vivo. Mice were transplanted with bone marrow overexpressing HoxA10 (or empty vector control) with or without activated SHP2 (E76K). To control for SHP2 overexpression, other mice were transplanted with bone marrow overexpressing HoxA10 and wild type SHP2. Mice transplanted with bone marrow overexpressing HoxA10 (±SHP2) developed MPD which evolved to AML over 4 mos, consistent with previous observations. However, mice transplanted with bone marrow overexpressing HoxA10 and E76K SHP2 developed AML within 4 wks. This rapid development of AML correlated with abnormalities in expression of myeloid specific HoxA10 target genes. These studies indicate the importance of HoxA10 post translational modification for physiologically relevant function and identify cooperating lesions which may be significant for disease progression in human AML.

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

Blood ◽

10.1182/blood.v120.21.3513.3513 ◽

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.

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Repositioning of Quinacrine for Treatment of Acute Myeloid Leukemia

Blood ◽

10.1182/blood.v124.21.3609.3609 ◽

2014 ◽

Vol 124 (21) ◽

pp. 3609-3609

Author(s):

Anna Eriksson ◽

Albin Osterros ◽

Sadia Hassan ◽

Joachim Gullbo ◽

Linda Rickardson ◽

...

Keyword(s):

Gene Expression ◽

Acute Myeloid Leukemia ◽

Cytotoxic Activity ◽

Tumor Cells ◽

Cell Lines ◽

Myeloid Leukemia ◽

Lymphocytic Leukemia ◽

Ribosomal Biogenesis ◽

Rheumatic Drug ◽

Acute Myeloid

Abstract Background: A promising strategy for new drug discovery is ‘repositioning’, in which a new indication for an existing drug is identified. Using this approach, known on-patent, off-patent, discontinued and withdrawn drugs with unrecognized cancer activity, can be rapidly advanced into clinical trials for the new indication. We here report findings from a library screen of pharmacologically active and mechanistically annotated compounds in leukemia cells from patients aiming at the identification of repositioning candidates. Methods and results: The LOPAC®, 1280substance library (Sigma-Aldrich), with 1266 mechanistically annotated compounds, were investigated for cytotoxic activity by the fluorometric microculture cytotoxicity assay (FMCA) on tumor cells from 12 patients with leukemia (4 acute lymphocytic leukemia, 4 acute myeloid leukemia [AML], 4 chronic lymphocytic leukemia), as well as on peripheral blood mononuclear cells (PBMC) from 4 healthy donors. Sixty-eight compounds were identified as hits, defined as having a cytotoxic activity (less than 50% cell survival compared with controls) in all leukemia subgroups at the 10µM drug concentration used for screening. Only one of the hit compounds, quinacrine, showed higher activity in the leukemic cells than in normal PBMCs and was therefore selected for further preclinical evaluation focusing on AML. The aminoacridine quinacrine has a wide range of biological and therapeutical applications, and has been used for decades outside hemato-oncology, notably as an anti-protozoal and anti-rheumatic drug. Its side effects and toxicity are well characterized. Quinacrine showed significant cytotoxic activity in all four AML cell lines tested (HL-60, Kasumi-1, KG1a and MV4-11). In tumor cells from another 9 patients with AML, the cytotoxic effect (IC50 median 1.8, range 0.8-4 µM) was significantly superior to that in normal lymphocytes and clearly dose-dependent. Analysis of quinacrine data from the National Cancer Institute growth inhibitory screen in 60 cell lines (NCI 60 GI 50 data) was performed with the help of the NCI Cellminer database (http://discover.nci.nih.gov/cellminer/), and indicated leukemia sensitivity. To examine the ability of quinacrine to reverse diagnosis-specific gene expression, we utilized the Nextbio bioinformatics software, with its gene expression signatures of drug exposed myeloid leukemia cell cultures (HL60). These queries showed that myeloid leukemias had high reversibility scores. Moreover, gene enrichment and drug correlation data revealed a strong association to ribosomal biogenesis nucleoli. Translation initiation was observed including a high drug-drug correlation with ellipticine, a known inhibitor of RNA polymerase I (Pol-I). To validate the latter results, gene expression analysis of HL-60 cells exposed to quinacrine were obtained using the protocol described by Lamb et al (Science, 2006, 313, 1929), showing down regulation of Pol-1 associated RNA. Supporting these findings, quinacrine induced early inhibition of protein synthesis. Conclusions: The anti-protozoal and anti-rheumatic drug quinacrine has significant in vitro activity in AML. The anti-leukemic effect may be mediated by targeting ribosomal biogenesis. Considering its favorable and well-known safety profile, clinical studies of quinacrine in AML should be considered. Disclosures No relevant conflicts of interest to declare.

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The Role of TWIST1 Gene Expression and Hypoxic Microenvironment in Acute Myeloid Leukemia

Blood ◽

10.1182/blood.v126.23.3839.3839 ◽

2015 ◽

Vol 126 (23) ◽

pp. 3839-3839

Author(s):

Emilia Carolina Malafaia ◽

A. Mario Marcondes ◽

Ekapun Karoopongse ◽

Daniele Serehi ◽

Maria de Lourdes L. F. Chauffaille ◽

...

Keyword(s):

Gene Expression ◽

Cell Cycle ◽

Bone Marrow ◽

Acute Myeloid Leukemia ◽

Myeloid Leukemia ◽

Leukemia Cells ◽

Twist1 Expression ◽

Disease Biology ◽

Acute Myeloid

Abstract TWIST1, a basic helix-loop-helix (bHLH) transcription factor, plays a critical role in mesodermal development and organogenesis. Overexpressed TWIST1 has been thoroughly related to epithelial-mesenchymal transition (EMT) in solid tumors (QIN Q et al., 2012) and has been described as an emerging risk factor in hematological neoplasms (MERINDOL et al., 2014). . Many questions remain to be addressed concerning to the role of TWIST1 in acute myeloid leukemia (AML). The understanding of TWIST1 in leukemia cells and its interaction with microenvironment can offer new insights in regards to disease biology and therapeutic targets for patients with AML. Objectives: 1) to evaluate the role of stroma contact and hypoxia in TWIST1 expression in myeloid cell lines. 2) To evaluate the functional impact of overexpressing TWIST1 on KG1a and PL21 cells. 3) To evaluate TWIST1 expression in primary cells of AML patients. Methods: In order to mimic bone marrow microenvironment, myeloid cells were co-cultured with mesenchymal HS5 cell line and PO2 1% was established with Smart -Trak¨ 2 (Sierra Instruments, Inc.) equipment. Quantitative mRNA was determined using TaqMan¨ Universal Master Mix (Applied Biosystems, Foster City, CA) and 3-step standard cycling conditions with sequence-specific primer TWIST1 normalized to the expression of β-actin. KG1a and PL21 cells were transduced with lentivirus vector carrying e-GFP ("enhanced green fluorescence protein") for stable expression of TWIST1. Transduced cells were sorted by FITC fluorochrome and then verified through western blot analysis with TWIST1 antibody. For quantification of apoptosis, cells were labeled with PE-conjugated antibody using annexin V-phycoerythrin and propidium iodide (BD Biosciences, USA). DAPI (4',6- diamidino-2-phenylindole dihydrochloride) was used to stain DNA and determine cell cycle information . Apoptosis and cell cycle were analyzed by FACS -Becton Dickinson Canto II (BD Biosciences). Statistical analysis was assessed with unpaired t test. Results: Hypoxia induced TWIST1 mRNA expression in OCIAML3, PL21, KG1a and ML1 cell lines (fold-increased 46.3, 29.8, 12.9 and 2.3 respectively). Cells expressing endogenous TWIST1 protein (OCIAML3 and ML1) showed resistance to apoptosis in a hypoxic microenvironment (normoxia versus hypoxia: OCI/AML3, 22.6 % vs 11.7% and ML1, 29.8% vs. 7.5%) in contrast, cells not expressing endogenous TWIST1 protein (KG1a and PL21) went to apoptosis in the same conditions. Thus, overexpressing TWIST1 in KG1a and PL21 induced apoptosis protection in hypoxia (KG1a unmodified vs. modified: 17.6 ± 6.3 vs. 2.8 ± 6.3, p=0.04; PL21 unmodified vs. modified: 26.9 ± 10.9 vs. 3.2 ± 0.6, p=0.04) (fig 1). We found increased TWIST1 mRNA levels in bone marrow samples of 23 AML patients (3.88 ± 1.59) compared with 5 healthy controls (0.54 ±0.25) (p= 0.02) (fig 2). Patients in the highest tertile of TWIST1 expression did not show differences in percentage of blasts in bone marrow and complete remission after treatment compared with patients in low and middle tertile. Conclusion: Our data suggest TWIST1 gene expression protects acute myeloid leukemia cells from apoptosis in a hypoxic microenvironment. Moreover, our results showed increased expression of TWIST1 in AML patients. Thus, TWIST1 is a potential gene involved in leukemogenesis and should be further explored to understand disease biology and potential therapeutic targets. Disclosures No relevant conflicts of interest to declare.

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A Rapid Culture Technique Produces Functional Dendritic-Like Cells from Human Acute Myeloid Leukemia Cell Lines

Journal of Biomedicine and Biotechnology ◽

10.1155/2011/172965 ◽

2011 ◽

Vol 2011 ◽

pp. 1-9 ◽

Cited By ~ 4

Author(s):

Jian Ning ◽

David Morgan ◽

Derwood Pamphilon

Keyword(s):

T Cells ◽

Acute Myeloid Leukemia ◽

Cell Surface ◽

Cell Lines ◽

Myeloid Leukemia ◽

Leukemia Cell ◽

Antigen Uptake ◽

Human Acute Myeloid Leukemia ◽

Ifn Γ ◽

Acute Myeloid

Most anti-cancer immunotherapeutic strategies involving dendritic cells (DC) as vaccines rely upon the adoptive transfer of DC loaded with exogenous tumour-peptides. This study utilized human acute myeloid leukemia (AML) cells as progenitors from which functional dendritic-like antigen presenting cells (DLC) were generated, that constitutively express tumour antigens for recognition by CD8+T cells. DLC were generated from AML cell lines KG-1 and MUTZ-3 using rapid culture techniques and appropriate cytokines. DLC were evaluated for their cell-surface phenotype, antigen uptake and ability to stimulate allogeneic responder cell proliferation, and production of IFN-γ; compared with DC derived from normal human PBMC donors. KG-1 and MUTZ-3 DLC increased expression of CD80, CD83, CD86, and HLA-DR, and MUTZ-3 DLC downregulated CD14 and expressed CD1a. Importantly, both KG-1 and MUTZ-3-derived DLC promoted proliferation of allogeneic responder cells more efficiently than unmodified cells; neither cells incorporated FITC-labeled dextran, but both stimulated IFN-γ production from responding allogeneic CD8+T cells. Control DC produced from PBMC using the FastDC culture also expressed high levels of critical cell surface ligands and demonstrated good APC function. This paper indicates that functional DLC can be cultured from the AML cell lines KG-1 and MUTZ-3, and FastDC culture generates functional KG-1 DLC.

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Highly Multiplexed Cell Surface Immunophenotyping with Genotyping and Concurrent Transcriptomic Analysis of NPM1 mutated Acute Myeloid Leukemia

Blood ◽

10.1182/blood-2021-151366 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 1288-1288

Author(s):

Devdeep Mukherjee ◽

Gege Gui ◽

Laura W. Dillon ◽

Christopher S. Hourigan

Keyword(s):

Gene Expression ◽

Acute Myeloid Leukemia ◽

Cell Surface ◽

Single Cell ◽

Myeloid Leukemia ◽

Type A ◽

Patient Specific ◽

Malignant Cells ◽

Surface Proteome ◽

Acute Myeloid

Abstract BACKGROUND: The pathogenesis of acute myeloid leukemia (AML) is often attributed to the presence of somatic allelic variant(s) in hematopoietic stem/progenitor cells. However, malignant clones may have heterogenous cell-surface immunophenotypes including overlap with non-malignant cells. While leukemia-associated immunophenotypes and difference from normal approaches are used for flow cytometric assessment during and after treatment, such analysis may underrepresent true leukemia disease burden. Assessments of AML measurable residual disease (MRD) using flow cytometry and molecular methods have been reported as discrepant. Single-cell RNA sequencing experiments have recently attempted to distinguish malignant cells based on gene expression and/or immunophenotypic profiles alone. We hypothesized that single-cell genotyping of mutated transcript(s) coupled with broad surface proteome and transcriptome profiling could provide an integrated multimodal method for AML characterization. METHODS: We adapted the previously reported "genotyping of transcriptomes" (PMID: 31270458) to identify cells carrying the NPM1 type A mutation commonly seen, and typically stable throughout the disease course, in AML. Healthy human peripheral blood mononuclear cells (PBMC) were mixed with an AML cell line carrying NPM1 type A mutation (OCI-AML3) at 7:3 ratio and labelled with 163 oligo-tagged antibodies. Single cell 3'v3 gene expression- (GEX), antibody derived tag- (ADT) and genotyping of NPM1 (GNPM) -libraries (10X Genomics) were sequenced on the NovaSeq 6000 (Illumina). Results were processed using Seurat 4.0 toolkit. RESULTS: In total, 72% (n=1680) of barcoded cells could be genotyped for NPM1. Of the genotyped cells, 59% (n = 986) were not NPM1 mutated. Visualization using Uniform Manifold Approximation and Projection (UMAP) showed separation of healthy PBMCs and OCI-AML3 cells using protein data, confirmed by annotation using NPM1 genotyping (Figure 1). We found a significant positive correlation between mRNA and corresponding cell surface protein expressions in non-mutated (Pearson's coefficient, r = 0.502, p = 6.87e-11) and NPM1 mutated (r= 0.392, p= 7.5e-7) cells. Compared to non-mutated, NPM1 mutated cells showed nearly 14-fold higher NPM1 transcript levels. In addition, a total 63 proteins were highly expressed on the surface of NPM1 mutated cells (Figure 2). Among these, CD33 and CD36 showed maximum 8-fold increase in expression. Other highly expressed proteins with at least >2.5-fold change were cell adhesion molecules (including CD328, CD155, and CD56), extracellular matrix binding proteins (CD49a/b) and interleukin receptor (CD123). CONCLUSION: Overall, our results demonstrate proof of principle that high-throughput cell surface proteome, transcriptome and genotyping analysis can be simultaneously performed to comprehensively and confidently characterize individual AML cells. Patient-specific multiomics data with broad cell-surface proteomic screening may allow novel target identification for monitoring and/or therapeutic intervention. Ongoing work will now use this methodology to characterize a cohort of NPM1 mutated AML patient samples. Figure 1 Figure 1. Disclosures Hourigan: Sellas: Research Funding.

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Different regulation of PARP1, PARP2, PARP3 and TRPM2 genes expression in acute myeloid leukemia cells

10.21203/rs.2.19004/v1 ◽

2019 ◽

Author(s):

Paulina Gil-Kulik ◽

Ewa Dudzińska ◽

Elżbieta Radzikowska-Büchner ◽

Joanna Wawer ◽

Mariusz Jojczuk ◽

...

Keyword(s):

Gene Expression ◽

Bone Marrow ◽

Acute Myeloid Leukemia ◽

Peripheral Blood ◽

Myeloid Leukemia ◽

Mrna Level ◽

Hematopoietic Stem ◽

Genes Expression ◽

Acute Myeloid Leukemia Cells ◽

Acute Myeloid

Abstract Acute myeloid leukemia (AML) is a heterogenic lethal disorder characterized by the accumulation of abnormal myeloid progenitor cells in the bone marrow, which results in hematopoietic failure. Despite various efforts in detection and treatment, many patients with AML die of this cancer. That is why it is important to develop novel therapeutic options, employing strategic target genes involved in apoptosis and tumor progression. The aim of the study was to evaluate PARP1, PARP2, PARP3, and TRPM2 gene expression at the mRNA level in the cells of the hematopoietic system of the bone marrow in patients with acute myeloid leukemia, bone marrow collected from healthy patients, peripheral blood of healthy individuals, and hematopoietic stem cells from the peripheral blood after mobilization.Results: The results found that the bone marrow cells of patients with acute myeloid leukemia (AML) show over expression of PARP1 and PARP2 genes and decreased TRPM2 gene expression. In the hematopoietic stem cells derived from the normal marrow and peripheral blood after mobilization, the opposite situation was observed, i.e. TRPM2 gene showed increased expression while PARP1 and PARP2 gene expression was reduced. We observed the positive correlations between PARP1, PARP2, PARP3, and TRPM2 genes expression in the group of mature mononuclear cells derived from the peripheral blood and in the group of bone marrow-derived cells. In AML cells significant correlations were not observed between the expression of the examined genes.Conclusions: Our research suggests that in physiological conditions in the cells of the hematopoietic system there is mutual positive regulation of PARP1, PARP2, PARP3, and TRPM2 genes expression. PARP1, PARP2, and TRPM2 genes at mRNA level deregulate in acute myeloid leukemia cells.

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

Blood ◽

10.1182/blood.v124.21.2228.2228 ◽

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.

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