scholarly journals Phenotypic Characterization of Leukemia-Initiating Stem Cells in Chronic Myelomonocytic Leukemia (CMML)

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 4223-4223
Author(s):  
Gregor Eisenwort ◽  
Alexandra Keller ◽  
Michael Willmann ◽  
Irina Sadovnik ◽  
Greiner Georg ◽  
...  
Keyword(s):  
Stem Cells ◽  
Board Of Directors ◽  
Research Funding ◽  
Advisory Board ◽  
Chronic Myelomonocytic Leukemia ◽  
Multicolor Flow Cytometry ◽  
Advisory Committees ◽  
Cd34 Cells ◽  
Myelomonocytic Leukemia

Chronic myelomonocytic leukemia (CMML) is a stem cell-derived hematopoietic neoplasm characterized by dysplasia, uncontrolled expansion of monocytic (progenitor) cells in the bone marrow (BM) and in the peripheral blood (PB), and an increased risk of progression to secondary acute myeloid leukemia (sAML). Patients with advanced CMML and sAML are often highly resistant to therapy and their prognosis is dismal. It is thought that drug resistance in myeloid malignancies is a quality of leukemia stem cells (LSC), but little is known about CMML-initiating and propagating LSC. We investigated the phenotype and functional behavior of putative CMML-initiating cells in 15 patients with CMML (7 females, 8 males; median age 73 years; range 45-82 years) and 6 with sAML following CMML (1 female, 5 males; median age 67.5 years; range 66-76 years). BM and/or PB samples were examined by multicolor flow cytometry using antibodies against CD34, CD38 and various additional surface markers and target antigens. In a subset of patients, putative stem and progenitor cells (CD34+ cells, CD34+/CD38─ cells and CD34+/CD38+ cells) were FACS-sorted to high purity (>95%) and were employed in xenotransplantation experiments or in drug testing experiments. We found that CMML-initiating and propagating LSC reside within the CD34+/CD38─ fraction of the malignant clone. Whereas highly purified CD34+ cells engrafted NOD.Cg-Prkdcscid Il2rgtm1Wjl Tg(CMV-IL3,CSF2,KITLG) 1Eav/MloySzJ (NSGS) mice with full-blown CMML (engraftment rate 44.8±26.0%), no CMML was produced by the bulk of CD34- monocytic cells (engraftment rate 0.8±0.5%; p=0.002). CMML engraftment was also detectable when transplanting unselected mononuclear cells (engraftment rate 19.7±10.9%). By contrast, no leukemic engraftment was produced by CD38+ CMML fractions (engraftment rate 0.1±0.1%; p=0.003), indicating that the NSGS-repopulating CMML LSC reside specifically in a CD34+/CD38- fraction of the clone. In sAML, both the CD34+/CD38- cell fraction (engraftment rate 92.2±6.2%) and the CD34+/CD38+ fraction (engraftment rate 80.5±7.2%) produced engraftment with AML blasts in NSGS mice. In a next step, we established the cell surface phenotype of CD34+/CD38- LSC in CMML and sAML. As assessed by multicolor flow cytometry, CD34+/CD38- CMML cells invariably expressed CD33/Siglec-3, CD117/KIT, CD123/IL3RA, CD133/AC133, CD135/FLT3, and IL-1RAP. In a subset of patients, CMML LSC also expressed CD52 (9/11 patients; 81%), CD114 (3/7 patients; 43%), CD184 (9/12 patients; 75%), CD221 (8/11 patients; 73%) and/or CLL-1 (7/13 patients; 54%). CMML LSC did not express CD25 or CD26. However, in patients with sAML, LSC also displayed CD25 (median fluorescence intensity, MFI: CMML: 0.9 vs. sAML: 23.0; p<0.001). Compared to hematopoietic stem cells in normal BM (NBM), CMML LSC displayed slightly increased levels of CD117/KIT (MFI CMML: 32.5 vs. MFI NBM: 15.0; p=0.019), CD135/FLT3 (MFI CMML: 1.9 vs. MFI NBM: 0.8; p=0.001), CD184/CXCR4 (MFI CMML: 1.6 vs. MFI NBM 0.9; p=0.027), and IL-1RAP (MFI CMML: 1.6 vs. MFI NBM: 0.8; p=0.004). No correlations between surface-marker expression on LSC and the type of CMML (CMML-0/1/2 or dysplastic vs. proliferative CMML) or the clinical course were found. To confirm the clinical relevance of expression of surface target antigens on CMML LSC, we applied the CD33-targeted drug gemtuzumab-ozogamicin (GO). As assessed by combined staining for LSC (CD34+/CD38-) and AnnexinV/DAPI, incubation of CMML LSC with GO (0.001-1 µg/ml) resulted in dose-dependent apoptosis in all donors tested, and the same result was obtained in the monoblastic cell lines THP-1 (GO at 1 µg/ml: 94.2±1.5% vs. control: 12.7±2.2%, p<0.05) and Mono-Mac-1 (GO at 1 µg/ml: 56.4±12.1% vs. control: 10.1±0.6% p<0.05). In conclusion, LSC in CMML and sAML reside within CD34+/CD38─ cell populations that express distinct profiles of surface markers and target antigens. During progression of CMML into sAML, LSC apparently acquire CD25. Characterization of CMML LSC and LSC in sAML should facilitate their enrichment and the development of LSC-eradicating therapies. Disclosures Hoermann: Novartis: Honoraria; Roche: Honoraria. Sperr:Celgene: Consultancy, Honoraria; Novartis: Honoraria. Sill:Astex: Other: Advisory board; Novartis: Other: Advisory board; AbbVie: Other: Advisory board; Astellas: Other: Advisory board. Geissler:Novartis: Honoraria; AOP: Honoraria; Roche: Honoraria; Amgen: Honoraria; AstraZeneca: Honoraria; Ratiopharm: Honoraria; Celgene: Honoraria; Abbvie: Honoraria; Pfizer: Honoraria. Deininger:Blueprint: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Honoraria, Research Funding; Ascentage Pharma: Consultancy, Honoraria; Fusion Pharma: Consultancy; TRM: Consultancy; Sangoma: Consultancy; Adelphi: Consultancy; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Humana: Honoraria; Incyte: Honoraria; Novartis: Honoraria; Sangamo: Consultancy. Valent:Pfizer: Honoraria; Blueprint: Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Celgene: Honoraria; Deciphera: Honoraria, Research Funding.

A Comparison of Chemotherapy + G-CSF Versus Plerixafor (Mozobil®) + G-CSF for Stem Cell Mobilization In Patients with Multiple Myeloma Treated with Lenalidomide

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 2258-2258
Author(s):  
Tomer M Mark ◽  
Adriana C Rossi ◽  
Roger N Pearse ◽  
Morton Coleman ◽  
David Bernstein ◽  
...  
Keyword(s):  
Stem Cells ◽  
Multiple Myeloma ◽  
Stem Cell ◽  
Board Of Directors ◽  
Research Funding ◽  
Cell Yield ◽  
High Dose ◽  
Advisory Committees ◽  
Cd34 Cells ◽  
Stem Cell Collection

Abstract Abstract 2258 Background: Prior use of lenalidomide beyond 6 cycles of therapy in the treatment of multiple myeloma (MM) has been shown to negatively impact stem cell yield, but this phenomenon can be overcome with the addition of high-dose cyclophosphamide to standard G-CSF mobilization. We hypothesized that the use of plerixafor (Mozobil®) would compare similarly to chemotherapy in rescuing the ability to collect stem cells in lenalidomide-treated myeloma. Methods: We performed a retrospective study comparing the efficacy of plerixafor + G-CSF mobilization (PG) to chemotherapy + G-CSF (CG) (either high-dose cyclophosphamide at 3g/m2 or DCEP [4-day infusional dexamethasone/ cyclophosphamide/ etoposide/cisplatin]) in 49 consecutive stem cell collection attempts in patients with MM exposed to prior lenalidomide. The primary endpoint was the ability to collect sufficient stem cells for at least two transplants (minimum 5×106 CD34+ cells/kg), comparing results in terms of total exposure to lenalidomide and time elapsed from lenalidomide exposure until the mobilization attempt. The secondary endpoint was number of apheresis days required to meet collection goal. Resilts: Twenty-four patients underwent PG mobilization and twenty-five with CG (21 with G-CSF + cyclophosphamide, 4 with G-CSF+DCEP). The two groups did not differ in terms of total amount of lenalidomide exposure: median number of lenalidomide cycles for patients mobilized with PG was 6.5 (range 1.2–86.6), vs. 6 (range 2–21.6), for patients mobilized with CG (P = 0.663). The median time between mobilization and last lenalidomide dose was also similar between the two groups: 57.5 (range 12–462) days for PG vs. 154 (range 27–805) days for CG (P = 0.101). There was an equivalent rate of successful collection of 100% for PG and 96% for CG, P = 0.322. One patient failed collection in the CG group due to emergent hospitalization for septic shock during a period of neutropenia; no patient collected with PG had a serious adverse event that interrupted the collection process. Stem cell yield did not differ between the two arms (13.9 vs. 18.8 × 106 million CD34+ cells/kg for PG vs. CG respectively, P = 0.083). Average time to collection goal was also equal, with a median of time of 1 day required in both groups, (range 1–2 days for PG, 1–5 days for CG, P = 0.073). There was no relationship between amount of lenalidomide exposure and stem cell yield with either PG (P = 0.243) or CG (P = 0.867). Conclusion: A plerixafor + G-CSF mobilization schedule is equivalent in efficacy to chemotherapy + G-CSF in obtaining adequate numbers of stem cells for two autologous stem cell transplants in patients with MM exposed to lenalidomide; however, PG may be a less toxic approach than chemomobilization. Number of lenalidomide cycles has no impact on chances of stem cell collection success using either method. Disclosures: Mark: Celgene Corp: Speakers Bureau; Millenium Corp: Speakers Bureau. Zafar: Celgene Corp: Speakers Bureau. Niesvizky: Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Millenium: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Onyx: Consultancy, Research Funding.

Inhibition of Chronic Myeloid Leukemia Stem Cells by the Combination of the Hedgehog Pathway Inhibitor LDE225 with Nilotinib

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 514-514 ◽  
Author(s):  
Bin Zhang ◽  
David Irvine ◽  
Yin Wei Ho ◽  
Silvia Buonamici ◽  
Paul Manley ◽  
...  
Keyword(s):  
Stem Cells ◽  
Board Of Directors ◽  
Colony Formation ◽  
Research Funding ◽  
Leukemia Stem Cells ◽  
Advisory Committees ◽  
Nsg Mice ◽  
Cd34 Cells ◽  
Hh Signaling

Abstract Abstract 514 Background: Tyrosine kinase inhibitors (TKI), although effective in inducing remissions and improving survival in CML patients, fail to eliminate leukemia stem cells (LSC), which remain a potential source of relapse on stopping treatment. Additional strategies to enhance elimination of LSC in TKI-treated CML patients are required. The Hedgehog (Hh) pathway, important for developmental hematopoiesis, has been shown to be activated in BCR-ABL-expressing LSC, in association with upregulation of Smoothened (SMO), and contributes to maintenance of BCR-ABL+ LSC. However the role of Hh signaling in chronic phase (CP) CML LSC is not clear. LDE225 (LDE, Novartis Pharma) is a small molecule SMO antagonist which is being clinically evaluated in patients with solid tumors. We have reported that LDE does not significantly affect proliferation and apoptosis of primary CP CML CD34+ cells, or reduce colony growth in CFC assays, but results in significant reduction in CML CFC replating efficiency and secondary colony formation. Treatment with LDE + Nilotinib resulted in significant reduction in colony formation from CD34+ CML cells in LTCIC assays compared to Nilotinib alone or untreated controls. These observations suggest that LDE may preferentially inhibit growth of primitive CML progenitors and progenitor self-renewal. We therefore further investigated the effect of LDE on growth of primitive CML LSC in vivo. Methods and Results: 1) CP CML CD34+ cells were treated with LDE (10nM), Nilotinib (5μ M) or LDE + Nilotinib for 72 hours followed by transplantation into NOD-SCID γ-chain- (NSG) mice. Treatment with LDE + Nilotinib resulted in reduced engraftment of CML CD45+ cells (p=0.06) and CD34+ cells (p=0.02) compared with controls, and significantly reduced engraftment of CML cells with CFC capacity (p=0.005). In contrast LDE or Nilotinib alone did not reduce CML cell engraftment in the bone marrow (BM) compared with untreated controls. LDE, Nilotinib, or LDE + Nilotinib treatment did not significantly inhibit engraftment of normal human CD34+ cells in NSG mice compared to controls. 2) We also used the transgenic Scl-tTa-BCR-ABL mouse model of CP CML to investigate the effect of in vivo treatment with LDE on CML LSC. BM cells from GFP-SCL-tTA/BCR-ABL mice were transplanted into wild type congenic recipients to establish a cohort of mice with CML-like disease. Recipient mice developed CML-like disease 3–4 weeks after transplantation. Transplanted CML cells were identifiable through GFP expression. Mice were treated with LDE225 (80mg/kg/d by gavage), Nilotinib (50 mg/kg/d by gavage), LDE + Nilotinib, or vehicle alone (control) for 3 weeks. Treatment with Nilotinib, LDE, and LDE + Nilotinib resulted in normalization of WBC and neutrophil counts in peripheral blood. LDE + Nilotinib treatment significantly reduced the number of splenic long term hematopoietic stem cells (LT-HSC, Lin-Sca-1+Kit+Flt3-CD150+CD48-, p<0.01) and granulocyte-macrophage progenitors (GMP) compared to controls, but did not significantly alter LT-HSC numbers in the BM. LDE alone reduced splenic LT-HSC but not GMP, whereas Nilotinib alone did not reduce LT-HSC numbers in spleen or BM but significantly reduced splenic GMP numbers. The mechanisms underlying enhanced targeting of LSC in the spleen compared to the BM are not clear but could reflect greater dependence on Hh signaling in the context of the splenic microenvironment and/or relocalization of LDE treated LT-HSC to BM. Experiments in which BM and spleen cells from treated mice were transplanted into secondary recipients to determine functional stem cell capacity of remaining LT-HSC are ongoing. Importantly mice treated with LDE + Nilotinib demonstrated enhanced survival on follow up after discontinuation of treatment compared with control mice or mice treated with LDE or Nilotinib alone. Conclusions: We conclude that LDE225 can target LSC from CP CML patients and in a transgenic BCR-ABL model of CP CML, and that LDE + Nilotinib treatment may represent a promising strategy to enhance elimination of residual LSC in TKI-treated CML patients. Disclosures: Buonamici: Novartis: Employment. Manley:Novartis: Employment. Holyoake:Novartis: Consultancy, Research Funding. Copland:Novartis Pharma: Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees. Bhatia:Novartis: Consultancy, Honoraria.

Phase Ib Study of Oral Panobinostat In Combination with 5-Azacitidine (5-aza) In Patients with Myelodysplastic Syndromes (MDS), Chronic Myelomonocytic Leukemia (CMML), or Acute Myeloid Leukemia (AML)

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 4957-4957 ◽  
Author(s):  
Pierre Fenaux ◽  
Daniel J DeAngelo ◽  
Guillermo Garcia-Manero ◽  
Michael Lübbert ◽  
Anand P. Jillella ◽  
...  
Keyword(s):  
Febrile Neutropenia ◽  
Adverse Events ◽  
Board Of Directors ◽  
Myeloid Leukemia ◽  
Research Funding ◽  
Chronic Myelomonocytic Leukemia ◽  
Advisory Committees ◽  
Dose Cohort ◽  
Phase Ib ◽  
Myelomonocytic Leukemia

Abstract Abstract 4957 Background: Panobinostat is a potent pan-deacetylase inhibitor (pan-DACi) that causes increased acetylation of target proteins such as HSP90, p53, α-tubulin and HIF-1α which are involved in cell cycle regulation, gene transcription, angiogenesis, and tumor cell survival. Preliminary evidence from phase I trials has demonstrated anti-tumor activity in patients with hematologic malignancies including myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). The advent of hypomethylating agents, such as 5-aza, represent a significant advancement in the treatment of MDS, chronic myelomonocytic leukemia (CMML), and AML. Although an improvement in clinical outcomes has been observed, including increased overall survival in patients with MDS, a substantial number of patients do not benefit from the therapies currently available. Preclinical studies suggest that the combination of a demethylating agent and a pan-DACi represents a rational strategy to reverse silencing of tumor suppressor genes, which contributes to the malignant phenotype, and improve outcomes in patients with MDS and AML. In this study, the combination of the pan-DACi, panobinostat, and the hypomethylating agent, 5-aza, was evaluated in patients with MDS, CMML and AML. Methods: This phase Ib, open-label, multicenter, dose-finding study is comprised of 2 stages: a dose-escalation stage to determine the maximum tolerated dose (MTD) of panobinostat in combination with standard dose 5-aza, and a subsequent expansion stage to evaluate safety, tolerability, and preliminary activity at the MTD dose level. The primary endpoint is incidence of dose-limiting toxicity (DLT) and secondary endpoints include type, duration, frequency, and relationship of adverse events (AEs) to the combination. Exploratory endpoints include clinical response and hematologic improvement according to IWG response criteria, and biomarker analysis of methylation status and expression of disease-associated genes in peripheral blood cells prior to and during therapy. Adult patients with IPSS INT-2 or high-risk MDS, CMML, or AML with multi-lineage dysplasia and ≤ 30% marrow blasts who are candidates for therapy with 5-aza and have not received a prior hypomethylating agent or pan-DACi are eligible for enrollment on the trial. Oral panobinostat was administered on Days (D) 3, 5, 8, 10, 12, and 15, starting at 20 mg, in combination with 5-aza (75 mg/m2 sc D 1–7) during a 28-D cycle. Patients received treatment for ≤ 6 cycles or until progression of disease, incidence of unacceptable toxicity, or withdrawal of consent. Results: To date, 11 patients have been enrolled including 9 patients with MDS, 1 patient with AML and 1 patient with CMML. The median age of patients enrolled on the trial was 69.0 (60-80). Patients have been evaluated at 2 panobinostat dose cohorts; 6 (20 mg) and 5 (30 mg). The AE analysis is based on 9 patients (6 from 20 mg cohort and 3 from 30 mg cohort) and the nature and incidence of AEs observed in the two cohorts were similar. Adverse events regardless of study drug relationship included nausea (4 [44%]), vomiting, fatigue (5 [55%] each) and asthenia (3 [33%]). Grade 3/4 AEs suspected to be treatment related included thrombocytopenia (2 [22%], febrile neutropenia and arthritis (1 [11%] each). Serious adverse events observed included febrile neutropenia, asthenia (2 [22%] each), atrial fibrillation and septic shock (1 [11%] each). One DLT has been observed (grade 4 febrile neutropenia) in the 20 mg panobinostat dose cohort. Conclusions: Panobinostat has been well tolerated up to a dose of 30 mg in combination with 5-aza (75 mg/m2) with dose escalation ongoing. Patients are currently being enrolled at the 40mg dose cohort. The most common AEs observed included febrile neutropenia, thrombocytopenia with one DLT observed (grade 4 febrile neutropenia) in the 20mg panobinostat dose cohort. The current data show that the addition of panobinostat to 5-aza is safe with no unexpected toxicities. Updated data, including safety and preliminary efficacy data will be presented at the meeting. Disclosures: Fenaux: Celgene: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Janssen Cilag: Honoraria, Research Funding; ROCHE: Honoraria, Research Funding; AMGEN: Honoraria, Research Funding; GSK: Honoraria, Research Funding; Merck: Honoraria, Research Funding; Cephalon: Honoraria, Research Funding. Off Label Use: Panobinostat is an investigational agent currently being evaluated for the treatment of hematologic and solid malignancies. DeAngelo: Novartis: Membership on an entity's Board of Directors or advisory committees. Sekeres: Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees. Winiger: Novartis Pharma AG: Employment. Squier: Novartis: Employment. Li: Novartis: Employment. Ottmann: Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees.

Transition of Chronic Myeloid Leukemia to Chronic Myelomonocytic Leukemia As a Tool to Observe Development of Chronic Myelomonocytic Leukemia

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 5223-5223
Author(s):  
Jamshid S Khorashad ◽  
Srinivas K Tantravahi ◽  
Dongqing Yan ◽  
Anna M. Eiring ◽  
Hannah M. Redwine ◽  
...  
Keyword(s):  
Board Of Directors ◽  
Myeloid Leukemia ◽  
Research Funding ◽  
Clonal Evolution ◽  
Chronic Myelomonocytic Leukemia ◽  
Imatinib Treatment ◽  
Advisory Committees ◽  
Clonal Architecture ◽  
Myelomonocytic Leukemia

Abstract Introduction. Development of abnormal Philadelphia (Ph) negative clones following treatment of chronic myeloid leukemia (CML) patients with imatinib has been observed in 3 to 9% of patients. Here we report on a 77 year old male diagnosed with CML that responded to imatinib treatment and subsequently developed chronic myelomonocytic leukemia (CMML). He achieved major cytogenetic response within 3 months but this response coincided with the emergence of monocytosis diagnosed as CMML. Five months after starting imatinib treatment the patient succumbed to CMML. We analyzed five sequential samples to determine whether a chronological order of mutations defined the emergence of CMML and to characterize the clonal evolution of the CMML population. Materials and Method. Five samples (diagnostic and four follow up samples) were available for analysis. CMML mutations were identified by whole exome sequencing (WES) in CD14+ cells following the onset of CMML, using CD3+ cells as constitutional control. Mutations were validated by Sequenom MassARRAY and Sanger sequencing and quantified by pyrosequencing. Deep WES was performed on the diagnostic sample to determine whether the mutations were present at CML diagnosis. To determine the clonal architecture of the emerging CMML, colony formation assays were performed on the diagnostic and the next two follow-up samples (Samples 1-3). More than 100 colonies per sample were plucked for DNA and RNA isolation. The DNA from these colonies were tested for the presence of the confirmed CMML mutations and the RNA was used for detection of BCR-ABL1 transcript using a Taqman real time assay. Results. Four mutations were identified by Sequenom and WES throughout the patient's time course [KRASG12R, MSLNP462H, NTRK3V443I and EZH2I669M ]. Sequenom did not identify these at diagnosis while deep WES did. Clones derived from colony formation assay revealed three distinct clones present in all samples analysed. Clone 1 had only KRASG12R, clone 2 had KRASG12R, MSLNP462H, and NTRK3V443I, and clone 3 had all four mutations. All clones containing any of these four mutations were BCR/ABL1 negative. Analysis of clonal architecture indicated that KRASG12R was acquired first and EZH2I669M last, while MSLNP462H and NTRK3V443I were acquired in between. These CMML clones increased proportionately as clinical CML metamorphosed into clinical CMML after initiation of imatinib therapy. Consistent with the colony data, pyrosequencing revealed that the ratio between the mutants remained largely stable throughout the follow up period. Conclusion. This case illustrates how targeted therapy impacts clonal competition in a heterogeneous MPN. While the CML clone was dominant in the absence of imatinib, it was quickly outcompeted by the CMML clones upon initiation of imatinib therapy. The clonal architecture analysis, in combination with in vivo kinetics data, suggest that the KRASG12R mutation alone was able to produce a CMML phenotype as clones with just KRASG12R remained at a relatively stable ratio during follow up. Unexpectedly, acquisition of additional mutations, including EZH2I669M as the last mutational event identified in this patient, did not increase clonal competitiveness, at least in the peripheral blood. These data show that clonal evolution may not invariably increase clonal fitness, suggesting that factors other than Darwinian pressures contribute to clonal diversity in myeloproliferative neoplasms. Disclosures Deininger: Gilead: Research Funding; Bristol-Myers Squibb: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees; Ariad: Consultancy, Membership on an entity's Board of Directors or advisory committees.

scholarly journals Overactivation of the NLRP3 Inflammasome in Chronic Myelomonocytic Leukemia KRAS Mutated Patients Can be Detected By the Apoptosis-Associated Speck-like Protein (ASC) and Reverted By IL1β Inhibitors

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 3670-3670
Author(s):  
Laura Hurtado-Navarro ◽  
Ernesto J Cuenca ◽  
Eva Soler ◽  
Andres Jerez ◽  
Helios Martínez-Banaclocha ◽  
...  
Keyword(s):  
Board Of Directors ◽  
Nlrp3 Inflammasome ◽  
Research Funding ◽  
Ex Vivo ◽  
Chronic Myelomonocytic Leukemia ◽  
Inflammasome Activation ◽  
Advisory Committees ◽  
Nlrp3 Inflammasome Activation ◽  
Myelomonocytic Leukemia

Abstract It has been recently shown that RAS mutations, which occur in 11-38% of Chronic Myelomonocytic Leukemia (CMML), do not only act via RAS/MEK/ERK signaling, but contribute to the disease through NLRP3 inflammasome activation (Hamarsheh, Nat Comm 2020). Despite a therapeutic approach based on NLRP3/IL1β axis blockade, as bring to a stem cell transplantation (SCT) has been proposed, data on the efficacy of IL1β inhibitors in hematopoietic neoplasms is limited. A 55 year old man with previous autoinflammatory episodes (constrictive pericarditis) was diagnosed on September 2020 of CMML-1 KRAS G12D (Inter-2). Due to worsening (orchiepidedymitis, pneumonitis, cellulitis), and the impossibility of performing an SCT at that time, on December 02 2020 he started anakinra (a IL1β receptor antagonist) with good response. Due to new episodes of autoinflammation, anakinra was discontinued (12 April 2021) with severe clinical worsening (heart failure) and no response to diuretic/corticosteroid. After anakinra was restarted (04 May 2021), a progressive improvement was seen, allowing a successful pericardiectomy before an SCT. We obtained blood samples from this patient (at different times) and plasma and whole blood samples from 11 and 5 other CMML KRAS mut patients, respectively. We also included CMML patients without KRAS mutations (KRAS wt) (n=8), with sepsis (n=5) and healthy individuals (n=9). Plasma levels of 15 inflammatory cytokines associated with NLRP3 inflammasome and NFkB pathways were measured using a customized MILLIPLEX ® kit. The inflammasome marker activation assays were conducted as previously published (Martínez García JJ, Nature Comm 2019). Compared to healthy controls, KRAS wt CMML patients did not show differences in any cytokine tested, except IL6, while KRAS mut patients showed significantly higher levels of IL1α, IL1ra, IL18, IL12p40 (associated with NLRP3 inflammasome), IL6, IL8 (associated with NFkB pathway) and M-CSF (Fig. 1A B). Compared to KRAS wt CMML patients, those with KRAS mut showed higher levels of cytokines associated with both the NLRP3 and NFkB pathways, reaching statistical significance for those related with NLRP3 inflammasome. We also observed changes in inflammasome related cytokines before and after anakinra (Table 1). This cytokine profile in the plasma made us analyze the oligomerization of ASC as a marker of inflammasome activation in monocytes of KRAS mut CMML. We found that in all cases of KRAS mut CMML patients around 30 to 80% of monocytes presented oligomers of ASC measured by the time of flight assay, while in healthy donors and KRAS wt CMML patients, ASC oligomerization occurred upon NLRP3 inflammasome activation with lipopolysaccharide (LPS) + ATP or Pyrin inflammasome activation with LPS and Clostridium difficile B toxin (TcdB) (Fig. 2A). Ex vivo activation of PBMCs from KRAS mut CMML patients showed that despite the high percentage of cells with ASC oligomers, very low levels of IL1b released from these cells, even when NLRP3 was activated with LPS+ATP (Fig. 2B), suggesting that this inflammasome is activated in vivo and could not be further activated ex vivo. As control, Pyrin inflammasome activation in PBMCs from KRAS mut CMML was able to induce IL1b release similarly to healthy controls (Fig. 2B). We then found that anakinra treatment of the KRAS mut CMML patient followed in this study, resulted in a decrease of the percentage of monocytes with basal active inflammasomes (Fig. 2C). A little ex vivo activation of the NLRP3 inflammasome was obtained when cells were treated with LPS+ATP, while Pyrin inflammasome was activated at normal levels after LPS+TcdB treatment (Fig. 2D). The inflammasome basal activation increased in the monocytes of the KRAS mut CMML patient after anakinra withdraw and during clinical deterioration and restarting anakinra (second arrow) decreased the basal percentage of monocytes with ASC oligomers (Fig. 2C). Since ASC oligomers are associated to pyroptosis via caspase 1 activation and gasdermin D processing, we then analyzed pyroptotic markers in the plasma of the patient during the time. ASC was increased when monocytes presented elevated percentage of ASC oligomers (Fig. 2E), suggesting that ASC detection could be a promising biomarker. Overall, we show that, in vivo, the NLRP3 inflammasome activation of KRAS mut CMML patients may revert with IL1β blockers. ASC could identify those candidates to receive this therapy. PI18/00316 Figure 1 Figure 1. Disclosures Jerez: Novartis: Consultancy; BMS: Consultancy; GILEAD: Research Funding. Bellosillo: Thermofisher Scientific: Consultancy, Speakers Bureau; Roche: Research Funding, Speakers Bureau; Qiagen: Consultancy, Speakers Bureau. Hernández-Rivas: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene/BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees. Ferrer Marin: Cty: Research Funding; Incyte: Consultancy, Research Funding; Novartis: Speakers Bureau.

Antibody-Targeting of IL-3 Receptor-α Increases the Susceptibility of CD34+ CML Progenitors to Dasatinib-Induced Cell Death,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3745-3745
Author(s):  
Eva Nievergall ◽  
Deborah L. White ◽  
Hayley Ramshaw ◽  
Angel F. Lopez ◽  
Timothy P. Hughes ◽  
...  
Keyword(s):  
Stem Cells ◽  
Flow Cytometry ◽  
Progenitor Cells ◽  
Board Of Directors ◽  
Myeloid Leukemia ◽  
Research Funding ◽  
Blast Crisis ◽  
Chronic Phase ◽  
Advisory Committees ◽  
Cd34 Cells

Abstract Abstract 3745 Despite the remarkable efficacy of tyrosine kinase inhibitors (TKIs) in the treatment of chronic myeloid leukemia (CML), Ph+ CD34+ progenitor cells remain detectable even in patients with stable complete cytogenetic response. Over 40% of patients in stable complete molecular remission will develop molecular relapse within 6 months of stopping imatinib. While the exact causes are largely unknown, one of the proposed mechanisms is the protection of leukemic stem and early progenitor cells by the paracrine or autocrine production of cytokines, such as IL-3, GM-CSF and G-CSF, which activate survival pathways that bypass TKI-induced cytocidal effects. In acute myeloid leukemia (AML), the IL-3 receptor α chain (CD123) is recognized as a specific marker for CD34+/CD38− stem cells and therefore is attracting increasing interest as a therapeutic target. However, the function of CD123 in CML remains to date mostly unexplored. The aim of this study is to investigate potential synergy between TKIs and CSL362 (a humanized antibody version of 7G3 against CD123) in targeting CML progenitor and stem cells. CD34+ and CD34+/CD38− cells were isolated from mononuclear cells of newly diagnosed CML chronic phase and blast crisis patients. Flow cytometry studies indicated significantly increased CD123 expression on CD34+/CD38− cells of CML patients in both chronic phase and blast crisis when compared to normal hematopoietic stem cells (p<0.01 and p<0.001 for chronic phase and blast crisis, respectively; Figure A). A functional relevance of increased CD123 expression was demonstrated by IL-3-dependent increase in STAT5 phosphorylation (260.5% of baseline with 20 ng/ml IL-3; n=12; p<0.001) in CML CD34+ cells. Dasatinib inhibits STAT5 phosphorylation by blocking BCR-ABL signaling but only in the absence of IL-3 (62.5% of baseline for dasatinib alone vs. 130.8% for dasatinib + IL-3; n=3; p<0.01). In agreement, IL-3 effectively rescues dasatinib-induced cell death, as evaluated by AnnexinV/7-AAD staining (103.3% vs. 72.45%, n=5; p<0.01) and CFU-GM colony forming assays (69.39% vs. 46.13% relative to no treatment control; n=4; p<0.05). CSL362, in turn, revokes IL-3-mediated STAT5 phosphorylation (37.12% vs. 130.8%; n=3; p<0.001) and cytoprotection (45.05% vs. 69.39% CFC; n=4; p<0.01). In order to further elucidate the role of CSL362, CML CD34+ cells were cultured with increasing concentrations of dasatinib in the presence of IL-3 and CSL362 or BM4 isotype-matched control antibody. Even at very low dasatinib concentrations, CSL362 significantly reduces CML CD34+ colony forming cells (p<0.05; Figure B). Together these results substantiate a relevant role for IL-3-mediated resistance in CML progenitor cells and additionally confirming the ability of CSL362 to effectively bind to CD123 and impede IL-3 function. CSL362 furthermore has been optimized to mediate antibody dependent cell cytotoxicity (ADCC). CSL362 causes specific cell lysis of CML CD34+ progenitor cells in co-culture with allogeneic Natural killer cells as determined by increased lactate dehydrogenase release (ADCC activity of 42.4% ± 8.1%; n=3) and a decrease in the number of CFU-GM colonies by 74.1 % ± 12.2% (n=3). Collectively, our results indicate that a combination of dasatinib and CSL362 inhibits CML progenitor cell survival more effectively in vitro. Therefore, targeting IL-3 receptor α with CSL362 in chronic phase and blast crisis CML patients might provide a novel specific treatment approach aiding the elimination of refractory chronic myeloid leukemic stem and progenitor cells. A: Flow cytometry analysis reveals that CD123 expression is significantly higher in CD34+/CD38− cells of CML patients in chronic phase (CML-CP) and blast crisis (BC-CML) as compared to normal patients (NP), as previously documented for AML patients. ** p<0.01, *** p<0.001 by unpaired, two-tailed Student's t-test. B: In the presence of IL-3, CSL362 significantly reduces the number of colony forming cells. CD34+ cells of de novo CML-CP patients were cultured with dasatinib (0 to 10 nM) +IL-3 (1 ng/ml) ± CSL362 or BM4 (isotype control for CSL362). After 72 hours of culture live cells were plated for CFU-GM assay and colonies were counted after 2 weeks. Mean ± SE of three independent experiments is shown, n=4, p<0.05 by two-way ANOVA. Disclosures: Nievergall: CSL: Research Funding. White:CSL: Research Funding. Lopez:CSL: Research Funding. Hughes:Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Ariad: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Hiwase:CSL: Research Funding.

Characteristics and Outcomes Of Patients (pts) With Multiple Myeloma (MM) Who Develop Therapy (t)-Related Myelodysplastic Syndrome (MDS), t-Chronic Myelomonocytic Leukemia (CMML), Or t-Acute Myeloid Leukemia (AML)

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1424-1424
Author(s):  
Naveen Pemmaraju ◽  
Dhaval Shah ◽  
Hagop M Kantarjian ◽  
Verena Wagner ◽  
Robert Z. Orlowski ◽  
...  
Keyword(s):  
Overall Survival ◽  
Acute Myeloid Leukemia ◽  
Board Of Directors ◽  
Myeloid Leukemia ◽  
Research Funding ◽  
Chemotherapeutic Agents ◽  
Chronic Myelomonocytic Leukemia ◽  
Advisory Committees ◽  
Myelomonocytic Leukemia ◽  
Acute Myeloid

Abstract Background There has been a significant improvement in the outcome for patients (pts) with MM over the last decade, mainly due to the availability of immunomodulatory (IMiD) drugs and proteasome inhibitors (PI). The improvement in survival has also increased the risk of second primary malignancies (SPM), such as therapy-related myelodysplastic syndrome (t-MDS), therapy-related chronic myelomonocytic leukemia (t-CMML) or therapy-related acute myeloid leukemia (t-AML). However, little is known about the characteristics and outcomes of pts with t-MDS, t-CMML or t-AML. Methods We aimed to study the characteristics and outcome of pts who developed t-MDS, t-AML and t-CMML as SPM after the treatment of MM. We reviewed our database of pts with MM who were treated at our institution between 1993 and 2011. We identified 49 pts who were diagnosed to have t-MDS, t-CMML, or t-AML. The primary objective of this study was to evaluate the time to develop t-MDS, t-AML and t-CMML, their response to treatment and overall survival. Results Median age of pts at diagnosis of MM was 61 years. Forty-seven (96%) pts had symptomatic MM, while 2 (4%) had asymptomatic myeloma. Forty-seven (95%) pts with symptomatic myeloma received systemic therapy. Eleven (22%) pts were treated with IMiD or PI: lenalidomide 3, thalidomide 6 and bortezomib 2. Thirty-eight (78%) pts were treated with various conventional chemotherapeutic agents including melphalan, cyclophosphamide, doxorubicin, vincristine, etoposide, cisplatin, idarubicin, thiotepa, busulfan, carmustine and cytarabine. Fourteen (28%) pts also received radiation therapy to the affected areas. Twenty (41%) pts underwent high-dose chemotherapy and autologous hematopoietic stem cell transplantation (auto-HCT). Fourteen pts received maintenance therapy after auto-HCT with either thalidomide, lenalidomide, dexamethasone or bortezomib. Median time from the diagnosis of MM to t-MDS, t-CMML or t-AML was 6 years [0 – 24]. Thirty-four (69 %) pts developed t-MDS, 12 (24%) t-AML, and 3 (6%) t-CMML. Median age at diagnosis of t-MDS, t- CMML, or t-AML was 65 years. Twenty-seven (79%) pts with t-MDS and all 12 pts with t-AML had complex/high risk cytogenetics. Most common cytogenetic abnormalities involved chromosome 5 and 7. Thirty four (69%) pts received at least 1 cycle of induction chemotherapy either with conventional chemotherapeutic agents or investigational drugs. Only 9 pts (26%) achieved complete remission (CR). Median duration of CR in these pts was 4 months [1 – 62]. Median overall survival (OS) of pts who received induction therapy was 6.0 months [0-30]. Five (11%) pts received an allogeneic stem cell transplant with three achieving CR. Median OS in this subgroup of pts was 18 months [9 – 23]. Median OS for all 49 pts after diagnosis of t-MDS, t-CMML or t-AML was 6.0 months [0 – 30] Conclusion Development of t-MDS, t-CMML, or t-AML in pts with MM is associated with a poor outcome. These pts in general have complex cytogenetic abnormalities, chemo-resistant disease, a short CR and OS. A better understanding of disease biology and novel therapeutic approaches are warranted. Disclosures: Orlowski: Bristol-Myers Squibb: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding; Celgene: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding; Millennium: The Takeda Oncology Company: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding; Onyx: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding; Resverlogix: Research Funding; Array Biopharma: Honoraria, Membership on an entity’s Board of Directors or advisory committees; Genentech: Honoraria, Membership on an entity’s Board of Directors or advisory committees; Merck: Membership on an entity’s Board of Directors or advisory committees. Qazilbash:Otsuka: Research Funding; Celgene: Honoraria, Membership on an entity’s Board of Directors or advisory committees; Millennium Pharmaceuticals: Honoraria, Membership on an entity’s Board of Directors or advisory committees; Onyx: Honoraria, Membership on an entity’s Board of Directors or advisory committees.

scholarly journals Hypomethylating Agent Therapy for Chronic Myelomonocytic Leukemia Does Not Impact Acute Myeloid Leukemia Transformation or Survival

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 6-7
Author(s):  
Sandrine Niyongere ◽  
Yamini Kathari ◽  
Zeba Singh ◽  
Emily J. Vannorsdall ◽  
Ashkan Emadi ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Board Of Directors ◽  
Myeloid Leukemia ◽  
Research Funding ◽  
Chronic Myelomonocytic Leukemia ◽  
Institutional Research ◽  
Research Support ◽  
Advisory Committees ◽  
Clinical Trial Research ◽  
Myelomonocytic Leukemia

Background: Chronic myelomonocytic leukemia (CMML) is a clonal hematopoietic stem cell disorder with features of both myeloproliferative neoplasm and myelodysplastic syndrome (MDS). CMML is characterized by persistent blood monocytosis &gt;1 x 109/L, bone marrow dysplasia in one or more hematopoietic cell lines, and increased risk of transformation to acute myeloid leukemia (AML). Our review of SEER Medicare data (Haematologica 2013;98:584) demonstrated that, compared to MDS, CMML has shorter overall survival (OS) and more frequent progression to AML. Hypomethylating agents (HMAs) have become standard therapy for CMML, with reported response rates of 37-69%, but their impact on AML transformation and OS is unclear. Methods: We retrospectively reviewed CMML patients treated at the University of Maryland Greenebaum Comprehensive Cancer Center between January 2000 and December 2019. Clinical characteristics, treatments, AML progression, time to AML progression (TTP), and OS were recorded and analyzed. Descriptive statistics were used for baseline characteristics and Kaplan-Meier analysis was performed for time-to-event data. Statistical analyses were performed using GraphPad Prism 8®. Results: We identified 71 patients with CMML, 82% male and 73% white, with a median age of 69 (range 25 - 96) years; 51% had &lt;10% bone marrow (BM) blasts and 45% had low-risk cytogenetic findings (normal karyotype or -Y). Most patients treated prior to 2005 received hydroxyurea and/or erythropoiesis-stimulating agents or were enrolled on clinical trials, while patients treated since 2005 received HMAs as primary therapy. Median follow-up was 41.1 months. The median OS of the entire cohort was 20 months, with 46% of patients progressing to AML with a median TTP of 11.5 months. By the MD Anderson Prognostic Scoring System at time of diagnosis, CMML was low-risk in 24 patients, intermediate-1 in 16, intermediate-2 in 14, and high-risk in 17. Forty-six patients received HMAs, with an overall response rate (ORR) of 54% (complete response or partial response), while 25 patients did not receive HMAs. Patient and disease characteristics were similar in HMA- and non-HMA-treated patients (Table 1). The estimated OS of HMA-treated patients was 20 months, compared to 14 months for non-HMA-treated patients (p =0.43) (Figure 1). AML transformation occurred in 52% of patients treated with HMAs, with TTP ranging from 3 to 65 months, and in 33% patients not treated with HMAs, with TTP ranging from 5 to 47 months. Most patients receiving HMAs (63%) received ≥ 6 cycles; 46% transformed to AML despite initial response, often in a sudden and unpredictable manner. HMAs were azacitidine in 13 patients, decitabine in 24, azacitidine followed by decitabine in 4, and decitabine followed by azacitidine in 5. Five CMML patients in our cohort underwent allogenic stem cell transplantation. Four of the five relapsed with transformation to AML post transplant, and only one patient remains in remission, 9 months post transplant. Conclusions: Despite a 54% ORR, HMA treatment did not have a significant impact on frequency of AML transformation, or OS in our cohort. Based on our data, favorable response rates previously reported with HMAs and also seen in our patients do not appear to translate into decreased frequency of AML transformation or prolonged OS. Though our study is a retrospective study with inherent selection bias, our results underscore the ongoing need for novel therapies and for clinical trials for CMML patients. Disclosures Niyongere: Kartos Therapeutics: Other: Received clinical trial research support with Kartos Therapeutics ; Forty Seven: Other: Received clinical trial research support with Forty Seven. Emadi:Amgen: Membership on an entity's Board of Directors or advisory committees; KinaRx: Other: co-founder and scientific advisor; NewLink Genetics: Research Funding; Genentech: Membership on an entity's Board of Directors or advisory committees; Servier: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Research Funding. Doung:Pfizer: Membership on an entity's Board of Directors or advisory committees, Other: clinical trial research support; Incyte: Other: clinical trial research support; Astex: Other: clinical trial research support; MedPacto: Other: clinical trial research support. Baer:Takeda: Other: Institutional research funding; Oscotec: Other: Institutional research funding; Kite: Other: Institutional research funding; Incyte: Other: Institutional research funding; Forma: Other: Institutional research funding; Astellas: Other: Institutional research funding; AbbVie: Other: Institutional research funding.

Effective Elimination of CML Progenitor and Stem Cells Through Combination of α-CD123 Antibody-Dependent Cell-Mediated Cytotoxicity and Tyrosine Kinase Inhibitor Treatment

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 32-32
Author(s):  
Eva Nievergall ◽  
Deborah L. White ◽  
Agnes S.M. Yong ◽  
Hayley S. Ramshaw ◽  
Samantha J. Busfield ◽  
...  
Keyword(s):  
Stem Cells ◽  
Nk Cells ◽  
Board Of Directors ◽  
Research Funding ◽  
Kinase Inhibitor ◽  
Target Cells ◽  
Molecular Response ◽  
Advisory Committees ◽  
Cd34 Cells

Abstract Abstract 32 Since the introduction of tyrosine kinase inhibitor (TKI) therapy overall survival and complete molecular response rates in chronic phase chronic myeloid leukemia (CP-CML) patients have significantly improved. However, leukemic stem cells (LSCs) and progenitor cells persist and are thought to be responsible for disease progression, development of TKI resistance and disease recurrence after stopping TKI therapy. Protection by cytokines, such as IL-3 and GM-CSF, provides a potential mechanism of LSC resistance. While in acute myeloid leukemia (AML) monoclonal antibody (mAb) targeting of IL-3 receptor α (CD123), a recognized marker for AML LSCs, has been studied in vitro and in vivo, similar investigations have not been undertaken in CML to date. CSL362 is a genetically-engineered form of the specific blocking mAb 7G3 optimized for Fc receptor binding to achieve maximal antibody-dependent cell-mediated cytotoxicity (ADCC) capacity. Here we investigate the expression of CD123 in CD34+ progenitors and CD34+CD38− LSCs, isolated from CP- and blast crisis (BC) - CML patients, and study the benefits of targeting those cells by CSL362 alone and in combination with TKIs. Flow cytometry analysis established significantly elevated expression of CD123 on CD34+CD38− cells from CP-CML (53.0 ± 5.8 %, n=16, p=0.003) and BC-CML (73.2 ± 6.7 %, n=18, p<0.001) patients compared to normal donors (20.3 ± 4.2 %, n=8), with clear increases in CD123 expression with disease progression in matched samples (n=2). Subsequent assessment of apoptosis, colony forming unit (CFU-GM) and long-term culture-initiating cell (LTC-IC) potential confirmed the ability of CSL362 to block IL-3-mediated rescue of TKI-induced cell death. However, in the presence of other cytokines, likely found in the physiological bone marrow microenvironment, this effect was lost. We also demonstrate by lactate dehyrogenase release and clonogenic assays that CML CD34+ cell numbers are significantly reduced, in a dose-dependent manner, by CSL362-induced ADCC employing NK cells from healthy donors (42.4 ± 8.1 % lysis, n=3, and CFU-GM decreased to 30 ± 10.8 % of controls, n=5, p=0.003). In keeping with this, flow cytometry analysis revealed specific elimination of CP- and BC-CML CD123+ CD34+CD38− cells (from 42.9 % to 18.6 %, n=5, p=0.004, and from 71 % to 35.3 %, n=3, p=0.044, respectively). Importantly, autologous CML patient NK cells, collected after achievement of major molecular response, also mediate CSL362-dependent cytotoxicity similar to allogeneic healthy donor NK cells as indicated by equivalent numbers of remaining CFUs (28 ± 6.7 % vs. 34.9 ± 3.4 %, n=5, Fig. A). We further have evidence to suggest preferential elimination of CML over normal LTC-ICs (30.3 ± 9.9 % vs. 62.6 ± 11.2 % remaining, n=3, p=0.096) in the autologous setting. Of clinical importance, the combination of Nilotinib and CSL362 resulted in a significantly greater reduction in CFUs (additive effect) when compared to either agent alone (Fig. B). Taken together these data suggest that selective ADCC-mediated lysis, likely the major mode of action of CSL362 in vivo, efficiently eliminates CML progenitor and stem cells. Promising results evaluating CSL362/TKI combination treatments, with the expectation to further enhance specificity for leukemic while sparing normal progenitor and stem cells as indicated from preliminary experiments, warrant further studies. A: Autologous NK cells are able to confer CSL362-induced ADCC against CML CD34+ cells. Cells were co-cultured at an effector to target cell ratio (E:T) of 10:1 in the absence and presence of CSL362 as indicated for 4 h and remaining CFU-GM were enumerated. Data is normalized to target cells alone (*** p<0.001). B: CSL362-mediated ADCC and TKI treatment show additive effects. CP-CML CD34+ cells were cultured with nilotinib at varying concentrations as indicated for 48 h before overnight exposure to CSL362 (1 μg/ml) with or without allogeneic NK cells (E:T 1:1). Mean ± SE of CFU-GM colony numbers is shown (n=3, * p<0.05, ** p<0.01). A: Autologous NK cells are able to confer CSL362-induced ADCC against CML CD34+ cells. Cells were co-cultured at an effector to target cell ratio (E:T) of 10:1 in the absence and presence of CSL362 as indicated for 4 h and remaining CFU-GM were enumerated. Data is normalized to target cells alone (*** p<0.001). . / B: CSL362-mediated ADCC and TKI treatment show additive effects. CP-CML CD34+ cells were cultured with nilotinib at varying concentrations as indicated for 48 h before overnight exposure to CSL362 (1 μg/ml) with or without allogeneic NK cells (E:T 1:1). Mean ± SE of CFU-GM colony numbers is shown (n=3, * p<0.05, ** p<0.01). Disclosures: Nievergall: CSL Ltd: Research Funding. White:BMS: Research Funding; CSL Ltd: Research Funding; Novartis Oncology: Honoraria, Research Funding. Ramshaw:CSL Ltd: Research Funding. Busfield:CSL Ltd: Employment. Vairo:CSL Ltd: Employment. Lopez:CSL Ltd: Research Funding. Hughes:Ariad: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis Oncology: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; CSL Ltd: Research Funding. Hiwase:CSL Ltd: Research Funding.

Modeling Chronic Myelomonocytic Leukemia Through Patient-Derived Induced Pluripotent Stem Cells

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 864-864
Author(s):  
Keisuke Kataoka ◽  
Kazuki Taoka ◽  
Masashi Miyauchi ◽  
Masataka Hosoi ◽  
Keiki Kumano ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Stem Cells ◽  
Induced Pluripotent Stem Cells ◽  
Pluripotent Stem Cells ◽  
Research Funding ◽  
Chronic Myelomonocytic Leukemia ◽  
Cd34 Cells ◽  
Induced Pluripotent ◽  
Myelomonocytic Leukemia

Abstract Chronic myelomonocytic leukemia (CMML), the most common entity among myelodysplastic syndrome/myeloproliferative neoplasm, is characterized by monocytosis, morphologic dysplasia, and progression to acute myeloid leukemia. Despite its relatively high incidence, the pathogenesis of CMML remains elusive, mainly due to the paucity of suitable animal models and the difficulties in the establishment of CMML cell lines. As reprogramming technology has been established as a new powerful tool for disease modeling, here we developed induced pluripotent stem cells (iPSC) from CMML leukemic cells. By introducing episomal vectors expressing OCT3/4, SOX2, KLF4, L-MYC, LIN28 combined with shRNA for p53, several lines of iPSC were generated from CD34+cells of a healthy donor (wild-type: WT) and a CMML patient with der (1; 7) (q10; p10) translocation. All iPSC expressed pluripotent surface markers (TRA1-60 and SSEA4) and stemness-related genes (NANOG, OCT3/4, SOX2, KLF4, C-MYC, and REL). The der (1; 7) (q10; p10) translocation were detected in all CMML iPSC. When co-cultured with 10T1/2 stromal cells in the presence of VEGF, CMML and WT iPSC generated a comparable frequency of CD34+ CD43+ hematopoietic progenitor cells (HPC). However, when cultured in cytokine-supplemented semisolid medium, CMML iPSC-derived CD34+ CD43+ HPC yielded an increased number of hematopoietic colonies with larger sizes, especially CFU-GM and CFU-GEMM, compared with WT iPSC-derived cells. Importantly, CMML iPSC-derived hematopoietic colonies mainly consisted of monoblasts with a high nucleus/cytoplasm ratio, while those of WT iPSC predominantly composed of macrophages. Flow cytometric analysis showed marked increases of CD34+ hematopoietic progenitors and CD13+ myeloid cells in CMML iPSC-derived hematopoietic colonies. Of note, among myeloid lineages, there were remarkable increases in CD14+ monocytic cells and CD24+ CD14- immature granulocytes, which were unique characteristics of human CMML. In addition, CMML iPSC-derived CD13+myeloid cells exhibited a weak expression of CD56, which was never detected in WT iPSC-derived cells, suggesting CMML iPSC-derived hematopoietic cells recapitulate the original phenotype of CMML. Notably, we found that CMML iPSC-derived HPC retained the ability to serially replate and generate colonies even after the fourth plating, although essentially no WT iPSC-derived colonies were detected after the second plating, suggesting enhanced self-renewal capacity of CMML iPSC-derived HPC. In addition, when cultured in methylcellulose without cytokines, CMML iPSC-derived HPC were able to form spontaneous hematopoietic colonies, in contrast to WT iPSC-derived cells that gave rise to almost no detectable colonies. Taken together, these results suggest CMML iPSC-derived HPC possess the multiple biologic properties of CMML leukemic blasts. Then, we conducted a comprehensive gene expression and DNA methylation profiling of WT and CMML parental CD34+ cells, iPSC, and iPSC-derived CD34+ CD43+ HPC. Strikingly, although gene expression and DNA methylation status were quite different between WT and CMML parental CD34+ cells (R2 = 0.72 for gene expression and 0.90 for DNA methylation), WT and CMML iPSC-derived HPC exhibited similar gene expression and DNA methylation pattern (R2= 0.92 and 0.96), indicating reprogramming followed by redifferentiation may enable to obtain more homogenous population of normal and CMML cells that reside in almost the same differentiation stage. Using these multi-omics platforms, we searched differentially expressed and methylated genes between WT and CMML iPSC-derived HPC to identify molecular abnormalities that contribute to the pathophysiology of CMML. Indeed, gene set enrichment analysis revealed that embryonic stem cell (ESC)-related gene sets were enriched in CMML iPSC-derived HPC, which is consistent with a previous report that showed murine MLL leukemia stem cells employ a transcriptional program shared with ESC. Functional analysis of candidate genes is underway to further define the molecular aberrations involved in the CMML pathogenesis. In summary, we have established a novel CMML model of patient-derived iPSC and revealed their derived HPC recapitulate the disease’s primary features. These findings highlight the iPSC as an attractive platform to investigate the cellular and molecular pathophysiology of CMML. Disclosures: Kurokawa: Novartis: Consultancy, Research Funding; Bristol-Myers Squibb: Research Funding; Celgene: Consultancy, Research Funding.

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