Increased Interleukin-8 (IL8)-CXCR2 Signaling Promotes Progression of Bone Marrow Fibrosis in Myeloproliferative Neoplasms

Introduction: Elevated pro-inflammatory cytokines are a hallmark feature of myeloproliferative neoplasms (MPNs). The pro-inflammatory cytokine interleukin-8 (IL8) is increased in patients with myelofibrosis (MF) and correlates with adverse outcome, including overall survival. Previously, the Levine/Fang labs identified increased IL8 secretion from individual CD34+ stem cells in a subset of MF patients. The role of IL8 and its cognate receptors CXCR1/2 in MF pathogenesis has not been delineated. Methods: Single-cell cytokine assays were performed on isolated CD34+ cells from 60 clinically annotated MPN patients (20 MF, 20 PV, 20 ET) using a previously described micro-chip platform (Kleppe et al, Can Disc 2013). 10 healthy donors (CD34+ cells from hip replacements) were used as controls. Integrated RNA-Seq and Assay for Transposase-Accessible Chromatin followed by next-generation sequencing (ATAC-Seq) was performed on CD34+ cells from MPN patients with and without expanded IL8 secreting clones for gene expression/chromatin accessibility analysis. To model the role of IL8-CXCR2 on fibrosis in vivo, the human MPLW515L transplant model (hMPLW515L) of MF was used. Specifically, wild-type (WT) murine bone marrow (Creneg-Cxcr2f/f; Cxcr2WT) or marrow lacking the CXCR2 receptor (VavCre-Cxcr2f/f; Cxcr2KO)were retrovirally infected with MSCV-hMPLW515L-IRES-GFP and transplanted into lethally irradiated WT recipient mice and monitored for disease. Blood counts, chimerism, and flow cytometry were assayed. Moribund mice were sacrificed and assayed for grade reticulin fibrosis and overall survival. Results: Single-cell cytokine assays confirmed an increased proportion of IL8-secreting CD34+ cells in MF patients (40%) in comparison to other MPN sub-types (10% PV/0% ET) (Figure 1A). MF patients with expanded IL8 secreting clones (defined as >50% of total CD34+ cells) had increased leukocytosis (p<0.0001), larger spleen sizes (p=0.0004), greater prevalence of constitutional symptoms (p=0.0084), and higher-grade reticulin fibrosis in marrow (Figure 1B) in comparison to MF patients without prevalent IL8 clones. IHC confirmed increased IL8 expression in marrow biopsies from 8/15 MF patients in comparison to 0/4 normal controls (Figure 1C), and high IL8 expression was also observed in MF splenic megakaryocytes (MKs) as well as in splenic stromal/endothelial cells not seen in normal spleen (Figure 1D). Integrated RNA-Seq/ATAC-Seq analysis of IL8-high MF patients confirmed up-regulation of IL8-CXCR2 signaling and enrichment in pro-inflammatory pathways (i.e TNFa, NFkB, etc) by GSEA, as well as increased expression/accessibility of pro-inflammatory genes S100A8 and S100A9-previously implicated in fibrosis development. Flow analysis of IL8-high MF CD34+ cells revealed enhanced surface expression of CXCR2 and its analog CXCR1, such that MF was characterized by increased IL8 ligand and receptor expression (Figure 1E) and coincided with enhanced NFkB pathway activity (Figure 1F). Consistent with this, colony forming assays of cultured MF CD34+ cells revealed enhanced colony output when cultured with IL8 compared to WT CD34+ cells-an effect ameliorated by co-treatment with the CXCR1/2 antagonist Reparixin (Figure 1G). In vivo, hMPLW515L adoptive transplant with Cxcr2KO hematopoietic donor cells demonstrated improved leukocytosis, thrombocytosis (Figure 2A) and splenomegaly in comparison to Cxcr2WT hMPLW515L recipient mice. Pathologic analysis revealed a reduction in reticulin fibrosis in bone marrow (Figure 2B) and spleen, translating into an improvement in overall survival (Figure 2C). Notably, a significant reduction in dysplastic MKs-a hallmark feature of MF-was also observed in Cxcr2KO hMPLW515L mice (Figure 2D) supporting a role for CXCR2 signaling in MK proliferation. Conclusion: IL8 secreting clones are associated with increased symptom severity and fibrosis grade in MF. Gene expression of MF CD34+ IL8 secreting clones shows up-regulation of inflammatory genes S100A8/A9, implicated in myofibroblast proliferation. Cxcr2 KO abrogates fibrosis formation and prolongs survival in the hMPLW515L model, and CXCR1/2 inhibition impairs colony forming capacity of MF CD34+ cells. These data suggest pharmacologic inhibition of this pathway should be investigated as potential therapy in MF and in PV/ET patients at high risk of fibrotic transformation. Disclosures Fan: IsoPlexis: Current Employment, Current equity holder in private company; Singleron Biotechnologies: Current Employment, Current equity holder in private company. Levine:Morphosys: Consultancy; Prelude Therapeutics: Research Funding; Qiagen: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Gilead: Honoraria; Loxo: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy; Amgen: Honoraria; Astellas: Consultancy; Imago: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; C4 Therapeutics: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; Isoplexis: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria, Research Funding; Lilly: Consultancy, Honoraria; Janssen: Consultancy. Hoffman:Protagonist: Consultancy; Abbvie: Membership on an entity's Board of Directors or advisory committees; Dompe: Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees; Forbius: Consultancy.

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Different Treatment Approaches to Blast Phase-Myeloproliferative Neoplasms

Blood ◽

10.1182/blood-2021-146945 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 3641-3641

Author(s):

Franco Castillo Tokumori ◽

Najla Al Ali ◽

Onyee Chan ◽

David A. Sallman ◽

Seongseok Yun ◽

...

Keyword(s):

Overall Survival ◽

Board Of Directors ◽

Initial Treatment ◽

Research Funding ◽

Clinical Characteristics ◽

Myeloproliferative Neoplasms ◽

Intensive Chemotherapy ◽

Blast Phase ◽

Advisory Committees

Abstract CONTEXT: Transformation to acute myeloid leukemia (AML) occurs in 5-20% of patients with myeloproliferative neoplasms (MPN). Overall survival in blast phase MPN (MPN-BP) is poor, usually in the range of 3 to 6 months, and is not significantly impacted by intensive chemotherapy. Current guidelines favor treatment with a hypomethylating agent (HMA), but survival remains poor, and allogeneic hematopoietic stem cell transplantation (AHSCT) holds the only potential for long term survival. OBJECTIVE: To describe the clinical characteristics and overall survival of MPN-BP according to different treatment approaches. DESIGN: Single-institution, retrospective analysis of 70 MPN patients that progressed to blast phase, who presented to our institution between 2001 and 2020. Transformation to AML defined as >20% myeloblasts in peripheral blood or bone marrow. We stratified the patients according to initial treatment strategy for AML. Baseline variables were compared between groups. Median overall survival (mOS) was measured from time of AML diagnosis to date of death. Kaplan-Meier plots were created to compare mOS. RESULTS: Among 70 MF patients that progressed to AML, initial treatment was: 19 best supportive care (BSC), 25 HMA (20 HMA only and 5 HMA + venetoclax), and 26 intensive chemotherapy (IC) [12 patients received standard "7+3" regimen with daunorubicin/idarubicin and cytarabine, 12 received high-dose cytarabine, cladribine +/- mitoxantrone (CLAG/CLAG-M), and 2 received CPX-351 (Vyxeos)]. Patients receiving IC were younger at time of leukemic transformation than those receiving BSC (median 63.9 years vs 72.9 years; p=0.029) or HMA (median 63.9 years vs. 69.0 years; p=0.026). Additionally, 70% of IC patients had an ECOG performance status of 0 or 1 compared to just 48% of patients receiving either BSC or HMA (p=0.088). Median OS for the entire cohort (n = 70) was 4.8 months. Compared to patients who received active treatment with HMA or IC, those treated with BSC had shorter survival (0.9 months vs 6.4 months; p=0.001). Median survival between patients treated with HMA and IC was not significantly different (4.5 months vs 9.6 months; p=0.13). Patients treated with IC were more likely to proceed to AHSCT (46% vs 5%; p < 0.001). Between HMA and IC groups, there was no difference in time from MPN-BP diagnosis to treatment (median 0.4 months vs 0.3 months; p=0.644) or total number of lines of treatment for MPN-BP. Focusing specifically on the role of AHSCT in patients treated with IC, we found that patients who received AHSCT had significantly longer mOS than those patients who did not (18.9 months vs 4.9 months; p=0.002), suggesting the beneficial role of intensive chemotherapy is critically tied to the ability to subsequently undergo AHSCT. Among patients who underwent AHSCT, 1-year and 2-year OS was 51% and 34%, respectively. In contrast, patients not receiving AHSCT had 1-year and 2-year OS of 14% and 2%, respectively. Independent of age, AHSCT (p=0.008) and receipt of therapy (p=0.017) significantly correlated with longer survival after AML diagnosis. Besides these factors, there were no significant differences in the clinical characteristics between the three groups. Acknowledging the limitations associated with small numbers, we did not note any difference in survival between patients who received HMA vs HMA + venetoclax (p=0.27). CONCLUSIONS: In MPN-BP, patients receiving treatment had superior outcomes to those that received BSC. Initial treatment with intensive chemotherapy was associated with non-significant improvement in survival; however, this appears to be critically linked to the receipt of AHSCT. In appropriate patients, intensive chemotherapy may be reasonable in an effort to provide an effective bridge to AHSCT. Still, this study reinforces the poor prognosis associated with MPN-BP and the desperate need for novel therapeutic approaches in this group of patients. Figure 1 Figure 1. Disclosures Sallman: AbbVie: Membership on an entity's Board of Directors or advisory committees; Magenta: Consultancy; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Syndax: Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy; Kite: Membership on an entity's Board of Directors or advisory committees; Shattuck Labs: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Aprea: Membership on an entity's Board of Directors or advisory committees, Research Funding; Agios: Membership on an entity's Board of Directors or advisory committees; Intellia: Membership on an entity's Board of Directors or advisory committees; Incyte: Speakers Bureau. Sweet: Bristol Meyers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; AROG: Membership on an entity's Board of Directors or advisory committees; Astellas: Consultancy, Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees. Padron: BMS: Research Funding; Kura: Research Funding; Incyte: Research Funding; Blueprint: Honoraria; Taiho: Honoraria; Stemline: Honoraria. Lancet: Daiichi Sankyo: Consultancy; Celgene/BMS: Consultancy; Millenium Pharma/Takeda: Consultancy; BerGenBio: Consultancy; AbbVie: Consultancy; Astellas: Consultancy; Agios: Consultancy; ElevateBio Management: Consultancy; Jazz: Consultancy. Komrokji: PharmaEssentia: Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy; Acceleron: Consultancy; Jazz: Consultancy, Speakers Bureau; BMSCelgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Taiho Oncology: Membership on an entity's Board of Directors or advisory committees; Geron: Consultancy; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Kuykendall: Novartis: Honoraria, Speakers Bureau; Prelude: Research Funding; Incyte: Consultancy; PharmaEssentia: Honoraria; CTI Biopharma: Honoraria; Celgene/BMS: Honoraria, Speakers Bureau; BluePrint Medicines: Honoraria, Speakers Bureau; Abbvie: Honoraria; Protagonist: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding.

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Small-Molecule Inhibition of PRMT5 Induces Translational Stress and p53 in JAK2V617F Mutant Myeloproliferative Neoplasms

Blood ◽

10.1182/blood-2018-99-118406 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 53-53 ◽

Cited By ~ 1

Author(s):

Stefan Sonderegger ◽

Loretta Cerruti ◽

Cedric Tremblay ◽

Emma Toulmin ◽

Jesslyn Saw ◽

...

Keyword(s):

Bone Marrow ◽

Protein Synthesis ◽

Board Of Directors ◽

Cancer Cell ◽

Research Funding ◽

Myeloproliferative Neoplasms ◽

Cancer Therapeutics ◽

Advisory Committees ◽

Initiation Of Translation ◽

Cd34 Cells

Abstract Background: Myeloproliferative neoplasms (MPN) are a diverse group of hematopoietic stem cell disorders. JAK2V617F gain-of-function is the most prevalent mutation, accounting for more than 60% of MPNs. PRMT5 was initially identified as a JAK-binding protein. Its enzymatic function catalyses the symmetric di-methylation of arginine on a variety of substrates, including histones and proteins of the splicing apparatus. It has been proposed that mutant JAK2 can phosphorylate PRMT5, leading to loss of methylation activity and promotion of erythropoiesis (Liu F. et al. Cancer Cell 2011). Based upon this study, it was proposed that enhancing PRMT5 activity may be a useful therapeutic measure (Skoda RC et al. Cancer Cell 2011). Aim: To determine the role of PRMT5 in JAK2V671F mutant hematopoiesis. Hypothesis: Inhibition of PRMT5 will exacerbate JAK2V617F hematopoiesis R esults: Using a conditional null allele, we deleted Prmt5 in embryonic development with the hematopoietic-specific VavCre transgene. This led to embryonic lethality at E9.5 due to absence of erythropoiesis but not other lineages. Similar embryonic lethality was observed using the erythroid specific EpoRCre transgene. Following a 350,000-compound library screen, we developed a potent and selective SAM-dependent inhibitor (CTx034) of PRMT5 similar to that reported by Chan-Penebre E. at al. Nat. Chem. Biol. 2015. Consistent with the genetic evidence that PRMT5 is most important for erythropoiesis, CTx034 was a potent inhibitor of erythropoiesis in cultures derived from healthy human CD34+ cells. This suppression of erythropoiesis was associated with activation of p53. However, progenitor assays of bone marrow cells from patients with MPN showed that JAK2V617F erythropoiesis was more sensitive to CTx034 than normal erythropoiesis. We established JAK2V617F bone marrow chimeric mice to directly compare the in vivo effects of PRMT5 inhibition on mutant and wild-type erythropoiesis within the same animal. Remarkably, these studies showed normalization of spleen size and erythropoiesis, comparable to the current standard of care, Ruxolitinib (Figure 1A-B). Importantly, CTx034 was well tolerated in healthy animals with no suppression of hematopoiesis. One of the major therapeutic challenges for MPN is the eradication of the malignant clone, which is rarely achieved with Ruxolitinib. The addition of MDM2 inhibitors, which activate p53, are currently in trial. Importantly, CTx034 not only suppressed JAK2-mutant erythropoiesis but also activated p53 in JAK2-mutant progenitors, unlike Ruxolitinib (Figure 1C). This result strengthens the therapeutic rationale for PRMT5 inhibitors in MPN. To understand how CTx034 inhibits erythropoiesis, we initially considered direct methylation effects on JAK-STAT signalling and p53. Challenging previous reports, we could find no evidence that JAK alters PRMT5 activity, no evidence that PRMT5 inhibition perturbs JAK-STAT signalling and no evidence that PRMT5 methylates p53. To look more broadly, we performed RNA-seq analysis of CD34+ cells following 72 hours exposure to CTx034. Globally, this demonstrated a potent 'starvation' signal with suppression of protein synthesis despite activation of the upstream mTOR signalling pathway. This suppression of protein synthesis could be linked to three mechanisms. First, CTx034 inhibited methylation of the Sm core complex of the spliceosome, leading to alternate splicing (skipped exons and retained introns) affecting the elongation initiation factor 2 (EIF2) pathway. Second, PRMT5 directly interacts with the translation initiation complex (eIF4A, eIF4B, eIF4E and the poly(A)-binding protein 1, PABP1. Moreover, mass spectrometry identified PABP1 as a new target of PRMT5. Treatment with CTx034 did not alter protein abundance of any of these factors but decreased the RNA binding capacity of PABP1, thereby preventing the correct formation of the initiation of translation complex. Finally, CTx034 perturbed polysome formation with loss of methylation of RPS10. C onclusion: Challenging previous reports, we show that PRMT5 inhibitors are an attractive and novel therapeutic for JAK2V617F MPN by targeting initiation of translation, ribosome biogenesis and activation of p53. Disclosures Sonderegger: CRC Cancer Therapeutics: Research Funding. Cerruti:CRC Cancer Therapeutics: Research Funding. Toulmin:CRC Cancer Therapeutics: Research Funding. Lane:Novartis: Consultancy; Janssen: Consultancy, Research Funding; Celgene: Consultancy. Stupple:CRC Cancer Therapeutics: Employment. Street:MERCK: Membership on an entity's Board of Directors or advisory committees; CRC Cancer Therapeutics: Employment, Patents & Royalties. Jane:CRC Cancer Therapeutics: Patents & Royalties. Altura:MERCK: Employment. Nicholson:MERCK: Employment. Curtis:MERCK: Membership on an entity's Board of Directors or advisory committees; CRC Cancer Therapeutics: Patents & Royalties, Research Funding.

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

Blood ◽

10.1182/blood.v116.21.514.514 ◽

2010 ◽

Vol 116 (21) ◽

pp. 514-514 ◽

Cited By ~ 6

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.

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Deregulation of TNFRSF18 (GITR) Through Promoter CpG Island Methylation Induces Tumor Proliferation in Multiple Myeloma

Blood ◽

10.1182/blood.v118.21.2424.2424 ◽

2011 ◽

Vol 118 (21) ◽

pp. 2424-2424

Author(s):

Yang Liu ◽

Yong Zhang ◽

Phong Quang ◽

Hai T Ngo ◽

Feda Azab ◽

...

Keyword(s):

Gene Expression ◽

Bone Marrow ◽

Flow Cytometry ◽

Board Of Directors ◽

Research Funding ◽

Plasma Cells ◽

Cpg Island ◽

Advisory Committees ◽

Brdu Assay

Abstract Abstract 2424 Introduction Tumor necrosis factor receptor super families (TNFRSFs) play an important role in activation of lymphocyte and cell apoptosis. However the function of TNFRSFs in multiple myeloma (MM) remains unknown. Loss of function mutation of Fas antigen (TNFRSF6) was identified in MM cells, thus suggesting the possible role of TNFRSFs in regulating MM pathogenesis. We therefore investigated the epigenetic mechanisms that may mediate inactivation of TNFRSFs and its functional role in MM. Methods Dchip software was utilized for analyzing gene expression dataset. DNA was extracted from both primary CD138+ MM plasma cells and MM cell lines using blood & tissue DNA isolation kit (Qiagen, Inc.). Expression of GITR in primary CD138+ plasma cells was detected by Imunohistochemistry (IHC) DNA methylation was analyzed by methylated DNA immunoprecipitation (Medip) assay and bisulfate sequencing. 5'azacytidine was used to demethylate genomic DNA. Gene expression was detected by qRT-PCR and confirmed at the protein level by flow cytometry and western-blot. Over-expression of GITR was obtained in MM1.S cells by using GITR recombinant plasmid and electroporation. Apoptosis was determined using Annexin/PI staining and flow cytometry analysis. Activation of apoptotic signaling was studied by western blot. Cell survival and proliferation were analyzed by MTT and BrdU assay, respectively. Recombinant GITR-lentivirus was obtained from the supernatant of culture medium after 72 hours transfection in 293 cells. GFP positive MM cells were sorted and analyzed by flow cytometry. In vivo effect of GITR on MM tumor growth was determined by injection of GITR over-expressing MM cells in null mice. Mice skull, femur and vertebrae were isolated after 4 weeks injection. Anti-human CD138+ mAb microbead was used to detect MM cells extracted from mice tissue by flow cytometry. Results Gene-expression profiling showed down-regulation of TNFRSFs, including TNFRSF11A, TNFRSF11B, TNFRSF8, TNFRSF10C, TNFRSF9, TNFRSF21, TNFRSF1B, TNFRSF1A and TNFRSF18, compared to normal plasma cells. Moreover, Our IHC results also showed that GITR expression was positive in primary CD138+ plasma cells from 9 normal bone marrow, but negative in 9 MM samples. Importantly, we found that low GITR expression significantly correlated with MM progression. Indeed, GITR gene levels were lower in smoldering and active MM patients compared to MGUS patients and normal donors. Promoter CpG island (CGI) methylation of GITR was indentified in 5 out of 7 MM primary bone marrow (BM)-derived CD138+ cells but not in normal BM-derived plasma cells. Bisulfate sequencing and Medip assay showed that methylation of GITR was significantly associated with GITR expression in 5 MM cell lines, including MM1.S, OPM1, U266, RPMI and INA6. Promoter CGI of GITR was highly methylated leading to complete silencing of GITR in MM1.S cell line. GITR expression was significantly up-regulated in MM cells upon treatment with the 5'azacytidine. MTT and BrdU assay revealed that the proliferation and survival of MM1.S cells was disrupted in the GITR over-expressing MM1.S cells, notably with inhibition of cell proliferation compared to control vector infected cells. Moreover induction of cytotoxicity in GITR over-expressing cells was confirmed by using GFP competition assay. GITR-induced apoptosis was supported by induction of caspase 8 and 3 cleavage. The inhibition of human CD138+ plasma cell growth in the bone marrow of SCID mice using a disseminated MM xenograft model was observed in the experimental group injected with GITR expressing cells compared to the control group after 4 weeks injection. Conclusion Our findings uncovered a novel epigenetic mechanism contributing to MM pathogenesis, showing the role of GITR methylation as a key regulator of MM cell survival. Disclosures: Roccaro: Roche:. Ghobrial:Novartis: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Millennium: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Myers Squibb: Research Funding; Noxxon: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding.

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Dose Dependent Enhancement Of Neutrophil Recovery By Infusion Of Notch Ligand Ex Vivo Expanded Cord Blood Progenitors: Results Of a Multi-Center Phase I Trial

Blood ◽

10.1182/blood.v122.21.297.297 ◽

2013 ◽

Vol 122 (21) ◽

pp. 297-297 ◽

Cited By ~ 4

Author(s):

Colleen Delaney ◽

Filippo Milano ◽

Ian Nicoud ◽

Shelly Heimfeld ◽

Chatchada Karanes ◽

...

Keyword(s):

Board Of Directors ◽

Research Funding ◽

Graft Failure ◽

Ex Vivo ◽

Chronic Gvhd ◽

Advisory Committees ◽

Neutrophil Recovery ◽

Cd34 Cells ◽

Primary Graft Failure

Abstract Introduction There is a strong clinical need to overcome the increased early non relapse mortality (NRM) associated with delayed neutrophil recovery following cord blood transplant (CBT). Therefore we established a methodology using Notch ligand (Delta1) as a strategy for increasing the absolute number of marrow repopulating CB hematopoietic stem/progenitor cells (HSPC). We previously reported preliminary results of the first 10 patients in 2010 demonstrating the ability of Notch-expanded CB HSPC to provide rapid myeloid recovery post-CBT.1 Herein we present the updated results on 23 patients accrued to this trial aimed at assessment of efficacy as well as the feasibility of overnight shipment of the expanded cell product to three outside institutions. Methods Between July 2006 and March 2013, 23 patients with hematologic malignancies were enrolled in this prospective multi-center Phase I trial coordinated by the Fred Hutchinson Cancer Research Center in which one CB unit was ex vivo expanded prior to infusion. Conditioning consisted of Fludarabine (75mg/m2), Cyclophosphamide (120mg/kg) and TBI (13.2 Gy) over 8 days. On day 0, the unmanipulated CB unit was infused first followed 4 hours later by infusion of the freshly harvested expanded CB cells. Graft versus host disease (GVHD) prophylaxis consisted of cyclosporine and MMF beginning on day -3. All CB grafts were 4-6/6 HLA-matched (A/B antigen level, DRB1 allele level) to the recipient. Engraftment, NRM, relapse and GVHD were calculated using cumulative incidence rates to accommodate competing risks. Overall survival was analyzed using Kaplan-Meier estimates. Results Patient diagnosis was AML (n=16), ALL (n=5) and biphenotypic leukemia (n=2). Nine patients (39%) were ≥CR2 and 5 were MRD+ at the time of transplant. Median age was 28 years (range, 4-43) and weight 70 kg (range, 16-91) with a median follow-up of 614 days (range, 271-2443). 22 patients received the expanded graft with one product not meeting release criteria. The cell doses infused were significantly higher in the expanded CB graft: 2.7 (1.5-6.3) vs 6.9 (0.4-27.6) x107 TNC/kg, p<0.0008; 0.15 (0.02-0.57) vs 7.7 (0.62-49.5) x106 CD34/kg, p<0.0001. HLA-matching and ABO incompatibility of the expanded and unmanipulated products were similar. The incidence of neutrophil recovery was 95% (95% CI, 71-100) at a median of 13 days (range, 6-41 days) among the 22 patients receiving expanded CB cells which is significantly faster than that observed in 40 recipients of two unmanipulated units otherwise treated identically at a median time of 25 days (range, 14 to 45; p<0.0001). The incidence of platelet recovery (>20 x 10^9/L) was 77% (CI 95%: 53- 89) by day 100 at a median of 38 days (range, 19 – 134). There was one case of primary graft failure. Importantly, rate of neutrophil recovery correlated with CD34+ cell dose/kg with 8 out of 11 patients receiving greater than 8x106 CD34+cells/kg achieved an ANC ≥ 500/µl within 10 days. 21 patients were evaluable for in vivo persistence of the expanded cells. Ten (48%) demonstrated in vivo persistence beyond one month post infusion. The expanded cell graft was persistent at day 180 in 7 patients, and in those that survived to one year, dominance of the expanded cell graft persisted in one patient. The incidences of grade II-IV and III-IV acute GVHD was 77% (95% CI, 53-89) and 18% (95% CI, 5-36%), respectively; mild chronic GVHD was observed in 4 patients and severe chronic GVHD in one. Probability of OS was 62% (95% CI, 37-79%) at 4 years. Notably, the cumulative incidence of NRM at day 100 was 8% (95% CI, 14-24%) and at 4 years was 32% (95% CI, 8-40%). Nine patients died at a median time of 216 days (range, 31-1578 days) with respiratory failure/infection the most common cause (n=6). There were two relapses at day 156 and 365 post-transplant, with one death due to relapse. Secondary malignancy and primary graft failure were the other 2 causes of death. Conclusions Infusion of Notch-expanded CB progenitors is safe and effective, significantly reducing the time to neutrophil recovery and risks of NRM during the first 100 days. An advantage for infusion of higher numbers of CD34+ cells/kg further demonstrates the need to develop methods that reproducibly provide even greater expansion of repopulating cells than currently achieved to improve efficacy and potentially cost effectiveness. 1. Delaney C, et al, Nat Med. 2010 Feb;16(2):232-6. Disclosures: Delaney: Novartis: DSMB, DSMB Other; Biolife: Membership on an entity’s Board of Directors or advisory committees; medac: Research Funding. Wagner:Novartis: Research Funding; cord use: Membership on an entity’s Board of Directors or advisory committees.

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The Ki67/CD138 Ratio Independently Predicts Overall Survival in the Upfront Treatment of Newly Diagnosed Multiple Myeloma

Blood ◽

10.1182/blood.v124.21.2016.2016 ◽

2014 ◽

Vol 124 (21) ◽

pp. 2016-2016

Author(s):

Tomer M Mark ◽

Peter Forsberg ◽

Ihsane Ouansafi ◽

Adriana C Rossi ◽

Roger N Pearse ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

Overall Survival ◽

Board Of Directors ◽

Research Funding ◽

Complete Response ◽

Newly Diagnosed ◽

First Line ◽

Advisory Committees ◽

Line Therapy

Abstract Background: Assessment of malignant plasma cell cycling via plasma cell labeling index (PCLI) has been a validated prognostic tool in multiple myeloma (MM) but the test requires specialized technical expertise and is not widely available. Ki67 is a well-known protein marker of cellular proliferation on immunohistochemical (IHC) staining with prognostic utility in other malignancies. In an effort to develop a simpler system to provide analogous information to PCLI, we used a novel IHC co-staining technique for CD138 and Ki67 to quantify plasma cells in active cycling. We then performed a retrospective analysis of the ratio of Ki67/CD138 (Ki67%) in newly diagnosed patients with multiple myeloma receiving 1st-line therapy to correlate with clinical outcomes. Methods: A retrospective cohort study of patients (pts) with treated symptomatic MM was performed by interrogation of the clinical database at the Weill Cornell Medical College / New York Presbyterian Hospital. For inclusion in the analysis, subjects must have started first-line treatment in the period of 2005-2010, and had available bone marrow biopsies. Double-staining with Ki67 and CD138 was performed by IHC. The Ki67% was calculated as the percent of plasma cells expressing CD138 that were also found to express Ki67. Treatment outcomes were stratified and compared based on %Ki67. Response was determined by monthly serum protein electrophoresis / immunofixation (IFX) with free light chain analysis according to International Multiple Myeloma Working Group (IMWG) guidelines. Pts who were IFX negative but had no subsequent bone marrow biopsy were classified as being in unconfirmed complete remission. Results: We identified 151 patients with newly diagnosed MM and available %Ki67 expression who received first-line therapy over the period of 2005-2010. Patient were subdivided into two groups based on %Ki67: Low: %ki67 <= 5%, n = 87; and High: %Ki67 >5, n=64, to allow for comparison of treatment response and survival analysis. Specific therapeutic agent exposure history did not differ significantly between patients. Both groups had similar depth of response rates (ORR) to front-line therapy, Table 1. Median progression-free survival for the high versus low %Ki67 groups approached statistical significance at 54 months (95% CI 30.8,67.4) versus 26.9 months (95% CI 21.6,40.2), respectively (P = 0.083). At data cut-off, there were 30 deaths in the low %Ki67 group (1-yr OS 93%, 5-yr OS 71%) and 36 deaths in the high %Ki67 group (1-yr OS 94%, 5-yr OS 62%). Median overall survival (OS) was not reached for Ki67% <= 5% (95% CI 97.3,NR) vs. 78.9 months (95% CI 55.9,93.1) for Ki67% > 5%, (P = 0.0434), Figure 1. Multivariate cox regression for factors with influence on OS showed that only high-risk cytogenetics (HR 2.05, 95% CI 1.17, 2.92, P = 0.027), ISS (HR 1.835, 95% CI 1.33, 3.60, P = 0.000), and %Ki67 group status had an independent effect on survival outcome. Low (<=5%) versus high (>5%) %Ki67 influenced overall survival with a hazard ratio of 1.76 (CI 1.07,2.92, P = 0.027). Survival after ASCT was significantly longer in the low %Ki67 group with median OS not reached (95%CI, 97.3, NR) versus 86.9 months (95% CI 43.9, NR) for high %Ki67 group (P = 0.04). Discussion: The ratio of IHC double positive Ki67 and CD138 of > 5% is an independent prognostic marker for overall survival in newly diagnosed MM undergoing 1st line therapy. The %Ki67 serves as a simpler and widely available analog to PCLI that can be presently performed in most hematopathology laboratories. Table 1: First Line Treatment and Best Response (modified IMWG Criteria) Ki67% <= 5(N = 87)n (%) Ki67% > 5(N = 64)n (%) P Treatment Exposure* Lenalidomide 59 (67.8) 48 (75) 0.34 Thalidomide 30 (34.5) 14 (21.9) 0.09 Bortezomib 25 (28.7) 14 (21.9) 0.34 Alkylating agent 11 (12.6) 4 (6.3) 0.19 ASCT 27 (31) 22 (34.4) 0.66 Best Response Overall Response (>= Partial response) 77 (88.4) 57 (89.1) 0.41 Complete response 15 (17.2) 22 (34.4) Unconfirmed complete response** 14 (16.1) 8 (12.5) Very good partial response 23 (26.4) 15 (23.4) Partial response 25 (28.7) 12 (18.8) Stable disease 9 (10.3) 5 (7.8) Progressive disease 1 (1.2) 2 (3.1) * Percentages do not add to 100% due to instances of concurrent therapy use ** Unconfirmed complete response: immunofixation negative, but no confirmatory bone marrow biopsy available Figure 1 Overall Survival by %Ki67 Figure 1. Overall Survival by %Ki67 Disclosures Mark: Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Millennium: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Onyx: Research Funding, Speakers Bureau. Rossi:Celgene: Speakers Bureau. Pekle:Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Millennium: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Perry:Celgene: Speakers Bureau. Coleman:Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Millennium: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Onyx: Honoraria. Niesvizky:Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Millennium: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Onyx: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau.

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Vorinostat Impairs Cellular Viability, Differentiation, Redox Homeostasis and Gene Expression in BCR-ABL-Negative Myeloproliferative Neoplasms

Blood ◽

10.1182/blood.v124.21.3222.3222 ◽

2014 ◽

Vol 124 (21) ◽

pp. 3222-3222

Author(s):

Bruno A Cardoso ◽

Helio Belo ◽

Antonio Almeida

Keyword(s):

Bone Marrow ◽

Board Of Directors ◽

Cell Lines ◽

Myeloproliferative Neoplasms ◽

Hdac Inhibitors ◽

Growth Arrest ◽

Dependent Manner ◽

Advisory Committees ◽

Expression Of Genes

Abstract Background: The classical BCR-ABL-negative myeloproliferative neoplasms (MPN) are characterized by increased proliferation of hematopoietic precursors in the bone marrow resulting in an elevated number of terminally differentiated cells. Despite the recent description of JAK2 activating mutations and other mutations, these do not completely explain the pathophysiology and clinical heterogeneity of MPN. Epigenetic modifications, particularly histone acetylation, play pivotal roles in the pathogenesis of several hematological malignancies, and treatment of such disorders with histone deacetylase inhibitors results cell death and proliferation arrest. Importantly, epigenetic agents have proven to be effective in several hematological malignancies. Aims: HDAC inhibition has demonstrated some efficacy in patients with MPN. In order to investigate the effects of HDAC inhibitors in MPN, we analyzed the impact of Vorinostat on the cellular biology of MPN cell lines and primary bone marrow samples. Material and Methods: MPN bone marrow samples were collected at diagnosis following informed consent in the course of routine clinical laboratory tests. Mononuclear cells were isolated by gradient separation were used for culture experiments and lysed for RNA extraction. RNA extracted from MPN primary samples was used to synthetize cDNA and the transcript levels of genes associated with Apoptosis, Proliferation, Epigenetic modifications and several Signaling pathways were analyzed by quantitative-PCR. MPN primary cells and MPN derived cell lines were incubated with Vorinostat and at different time points the cells were harvest, lysed for gene expression analysis and stained with different antibodies, Annexin-V/PI and DCF-DA to analyze cellular differentiation, apoptosis and Reactive Oxygen Species (ROS) respectively. Results: We performed a targeted-genome wide screen and compared the transcript levels of a defined set of genes between normal bone marrow and MPN primary samples. We identified 9 genes (BIRC3, TNFRSF9, DLL4, IL1B, CDKN1A, FOSL1, CREL, SERPINB9 and EGR1) whose expression increased for at least 4 fold and 2 genes (HIP1 and DTX1) whose expression decreased by at least 0.5 fold in MPN patients relative to normal bone marrow samples. Interestingly, incubation of Vorinostat in MPN cell lines at physiological concentrations increases the expression of such genes, and also the expression of genes associated with apoptosis and growth arrest while decreasing the expression of genes associated with proliferation, growth arrest and JAK-STAT signaling pathway. Regarding cellular physiology, Vorinostat induces apoptosis in MPN cultured cell lines in a time- and dose-dependent manner. Furthermore, incubation of primary MPN bone marrow samples with Vorinostat induced apoptosis, blocked differentiation and also diminished ROS levels in a dose dependent manner. These effects were most marked in the monocytic lineage, a population which expresses the highest levels of ROS. Vorinostat also reduced the levels of GPA and CD61, markers of erythroid and megakaryocytic differentiation, respectively. Summary/Conclusions: Here, we show that Vorinostat incubation impairs MPN cellular differentiation and reduces ROS and cellular viability, possibly through the down-regulation of genes associated with cellular proliferation, particularly the JAK-STAT target genes, and up-regulation of genes important for apoptosis and growth arrest. Interestingly, the genes that we identified to be up-regulated in MPN primary samples relative to normal controls, are further increased by Vorinostat treatment, suggesting that these could act as potential biomarkers for Vorinostat effectiveness in the MPN context. Furthermore, these results hold therapeutic promise as Vorinostat reduced differentiation markers associated with Polycythemia Vera and Essential Thrombocytosis. The observation that Vorinostat is particularly effective against the monocytic lineage is interesting in the context of the recently described role of bone marrow monocytes in the pathogenesis of Polycythemia Vera in mouse models. Our results point towards the potential role of Vorinostat (and possibly other HDAC inhibitors) in the treatment of MPN. This potential would require clinical trials to investigate its efficacy. Disclosures Almeida: Celgene: Consultancy; Novartis: Consultancy; Amgen: Membership on an entity's Board of Directors or advisory committees; Shire: Membership on an entity's Board of Directors or advisory committees; Bristol-Meyer Squibb: Membership on an entity's Board of Directors or advisory committees.

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RON Kinase Is a Novel Therapeutic Target for Philadelphia-Negative Myeloproliferative Neoplasms

Blood ◽

10.1182/blood-2021-148192 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 1462-1462

Author(s):

Lindsay Meg Gurska ◽

Rachel Okabe ◽

Meng Maxine Tong ◽

Daniel Choi ◽

Kristina Ames ◽

...

Keyword(s):

Bone Marrow ◽

Board Of Directors ◽

Research Funding ◽

Myeloproliferative Neoplasms ◽

Marrow Transplant ◽

Jak Inhibitor ◽

Advisory Committees ◽

Hematopoietic Stem ◽

Stat Signaling ◽

Genetic Deletion

Abstract The Philadelphia-chromosome negative myeloproliferative neoplasms (MPNs), including polycythemia vera (PV), essential thrombocytosis (ET), and primary myelofibrosis (PMF), are clonal hematopoietic stem cell disorders characterized by the proliferation of one or more myeloid lineage compartments. Activation of JAK/STAT signaling is a major driver of all Ph-negative MPNs. During disease progression, MPN patients experience increased pro-inflammatory cytokine secretion, leading to remodeling of the bone marrow microenvironment and subsequent fibrosis. The JAK inhibitor ruxolitinib is an approved targeted therapy for MPN patients and has shown promise in its ability to reduce splenomegaly and the cytokine storm observed in patients. However, JAK inhibitors alone are not sufficient to reduce bone marrow fibrosis or to eliminate the JAK2-mutated clone. Furthermore, JAK inhibitor persistence, or reactivation of JAK/STAT signaling upon chronic JAK inhibitor treatment, has been observed in both MPN mouse models and MPN patients. Therefore, there is an urgent need for new treatment options in MPN. The tyrosine kinase RON, a member of the MET kinase family, has well-characterized roles in erythroblast proliferation and pro-inflammatory cytokine production. RON can be phosphorylated by JAK2 to stimulate erythroblast proliferation. However, the role of RON in MPN pathogenesis is unknown. We found that the ALK/MET/RON/ROS1 inhibitor crizotinib inhibited colony formation by MPN patient CD34+ cells, regardless of their disease subtype, mutation status, or JAK2 inhibitor treatment history (Figure 1A). To determine whether this is due to inhibition of the JAK/STAT signaling pathway, we performed phospho-flow cytometry of STAT3 and STAT5 in myelofibrosis patient erythroblasts treated with crizotinib ex vivo as well as Western blot analysis in the JAK2-mutated cell lines SET2 and HEL. We found that crizotinib inhibits the phosphorylation of JAK2, STAT3, and STAT5 (Figure 1B). Since crizotinib has not been reported to directly inhibit JAK2, we asked whether these effects of crizotinib in MPN cells could be explained by RON inhibition. Consistent with this hypothesis, we observed that shRNA knockdown of multiple RON isoforms also decreases the phosphorylation of JAK2, STAT5, and STAT3 in HEL cells (Figure 1C-D). To determine whether crizotinib can alter the MPN disease course in vivo, we tested crizotinib by oral gavage in the MPLW515L bone marrow transplant murine model of myelofibrosis at 100mg/kg daily for 2 weeks. We showed that crizotinib decreased the disease burden of MPL-W515L mice, as evidenced by decreased spleen and liver weights (Figure 1E). To determine the effects of RON genetic deletion on MPN pathogenesis, we tested whether genetic deletion of Stk (mouse gene for RON) impairs disease progression in the JAK2V617F bone marrow transplant MPN model by transplanting Stk-/- c-Kit+ bone marrow cells transduced with the JAK2V617F-GFP retrovirus into lethally irradiated recipients. We observed a significant delay in disease onset in Stk-/- transplant recipients compared to WT controls (Figure 1F). However, we found that Stk-/- mice have normal numbers of hematopoietic stem and progenitor cells, and normal bone marrow myeloid colony forming capacity, suggesting that RON is a safe therapeutic target. To determine whether RON plays a role in the JAK inhibitor persistence phenotype, we generated persistent cells by treating SET2 cells with increasing doses of ruxolitinib over 8 weeks, and confirmed persistent proliferation and JAK/STAT activation. Interestingly, we found that RON phosphorylation is enhanced in JAK inhibitor persistent cells, and that dual inhibition of RON and JAK2 overcomes JAK inhibitor persistence in SET2 cells (Figure 1G-H), suggesting that RON may potentiate the JAK2 persistence phenotype in response to ruxolitinib. Importantly, we showed by immunoprecipitation that phospho-RON and phospho-JAK2 physically interact in JAK inhibitor persistent SET2 cells, and that this interaction is disrupted by crizotinib (Figure 1I). In summary, our data demonstrate that RON kinase is a novel mediator of JAK/STAT signaling in MPNs, and that it plays a particularly important role in JAK inhibitor persistence. Our work suggests that therapeutic strategies to inhibit RON, such as crizotinib, should be investigated in MPN patients. Figure 1 Figure 1. Disclosures Halmos: Guardant Health: Membership on an entity's Board of Directors or advisory committees; Apollomics: Membership on an entity's Board of Directors or advisory committees; TPT: Membership on an entity's Board of Directors or advisory committees; Eli-Lilly: Research Funding; Advaxis: Research Funding; Blueprint: Research Funding; Elevation: Research Funding; Mirati: Research Funding; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding; GSK: Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Boehringer-Ingelheim: Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Astra-Zeneca: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Membership on an entity's Board of Directors or advisory committees, Research Funding. Gritsman: iOnctura: Research Funding.

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Prognostic Significance of Bone Marrow Cellularity in the Outcome of Patients with Myelodysplastic Syndromes Treated with Azacyitidine: A Retrospective Analysis from the Hellenic MDS Study Group

Blood ◽

10.1182/blood-2019-131003 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 5417-5417

Author(s):

Elena E. Solomou ◽

Alexandra Kourakli ◽

Anna Vardi ◽

Ioannis Kotsianidis ◽

Panagiotis Zikos ◽

...

Keyword(s):

Bone Marrow ◽

Overall Survival ◽

Board Of Directors ◽

Research Funding ◽

Hypomethylating Agents ◽

Advisory Committees ◽

Female Ratio ◽

Bone Marrow Cellularity ◽

Marrow Cellularity ◽

Male To Female

Introduction: Clinical trials in patients with high risk myelodysplastic syndromes (MDS) have shown that these patients benefit from the available hypomethylating agents 5-azacytidine and decitabine. The majority of these patients display hypercellular bone marrow, but a small proportion despite the excess of blasts, exhibit marrow hypocellularity (<30% cellularity). Data are limited for the efficacy and safety of treatment with hypomethylating agents in this patient subgroup. In the present study we examined the effect of bone marrow cellularity in the overall survival in patients with MDS treated with azacitidine. Patients & Methods: This is a retrospective multicenter study from the Hellenic National MDS Registry (EAKMYS) on behalf of the Hellenic MDS Study Group. Between 1.1.2009 and 31.12.2018 a total of 1161 MDS patients who have received treatment with azacytidine have been registered. Complete patient information and follow-up were available for 989 patients, and all these have been included in the final analysis. Statistical analysis was performed and overall survival (OS) was evaluated, using Kaplan-Meier estimates (GraphPad Prism software, CA). A p value less than 0.05 was considered statistically significant. Results: Forty nine patients had a hypocellular bone marrow (hMDS), representing the 4.95% of the whole patient population. Of these patients 39 were men (5.3% of all men included in the study) and 10 were women representing the 2.98% of all women enrolled (male to female ratio 3.9). In the non-hypoplastic group, 750 were men and 358 were women (male to female ratio 2.09). The median age at diagnosis for the hMDS group was 70.8 years, compared to 72.8 years in the non-hypoplastic group. The IPSS-R prognostic risk categorization included 15 hMDS patients in the low group, 9 in the intermediate, 14 in the high and 11 in the very high risk group. Twenty-six patients (53%) of the hMDS group had bone marrow blasts between 10 and 20%, and the remaining 23 (47%) had 5-10% blasts. The patients with hMDS received an average of 10 cycles of azacytidine treatment during the follow-up period (range 2-29 cycles). The outcomes tested were overall survival and progression to AML. The median overall survival of patients with hMDS, following azacytidine treatment start, was not significantly different from the median survival of patients with non-hypoplastic MDS [20 months versus 16 months in the non-hypoplastic group (95% CI of ratio: 0.839 to 1.863). The survival curves were not significantly different between the hMDS and non-hypoplastic MDS group (p=0.32, Figure 1). Progression to AML was also evaluated. Eleven (22.4 %) hMDS patients showed disease progression to AML. Patients with hMDS had significantly prolonged estimated median time to AML transformation, compared to the non-hypoplastic MDS population (31.7 versus 22 months respectively, p<0.001). There were not any major safety issues among patients with hMDS, despite the increased RBC and Platelet transfusion needs. The infectious episodes and the hospitalization courses did not differ significantly between the hMDS and the non-hypoplastic group. Discussion and Conclusive remarks: In this retrospective study, in which a large number of MDS patients was analyzed, we showed that bone marrow cellularity does not affect the outcome in patients treated with azacyitidine. Patients with hMDS show statistically significant slower AML progression compared to non-hypoplastic MDS. Bone marrow cellularity should not be a contraindication for using hypomethylating agents as a therapeutic option, and this type of treatment can be used safely, when indicated, also in patients with hMDS. Disclosures Pappa: Amgen: Research Funding; Gilead: Honoraria, Research Funding; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene / GenesisPharma: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Research Funding; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Honoraria, Research Funding, Speakers Bureau; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Vassilakopoulos:Merck: Honoraria; Takeda Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Genesis Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Astellas: Honoraria; Winmedica: Honoraria; Servier: Membership on an entity's Board of Directors or advisory committees. Symeonidis:Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; MSD: Membership on an entity's Board of Directors or advisory committees, Research Funding; Tekeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Research Funding; Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding.

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A Calreticulin Neoepitope-Directed Monoclonal Antibody Can Overcome JAK Inhibitor Resistance and Block TPO-Independent Megakaryocyte Differentation

Blood ◽

10.1182/blood-2021-154332 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 3597-3597

Author(s):

Denis Tvorogov ◽

Chloe AL Thompson-Peach ◽

Johannes Foßelteder ◽

Mara Dottore ◽

Frank Stomski ◽

...

Keyword(s):

Bone Marrow ◽

Board Of Directors ◽

Research Funding ◽

Liquid Culture ◽

Jak Inhibitor ◽

Advisory Committees ◽

Nsg Mice ◽

Cd34 Cells ◽

Calr Mutations ◽

Bone Marrow Engraftment

Abstract Introduction: Mutations within the gene encoding calreticulin (CALR) are the second most common genetic aberration associated with primary myelofibrosis (PMF), observed in 70% of non-JAK2 V617F cases. Importantly, patients with CALR mutations do not effectively respond to JAK inhibitor therapy and no mutation specific therapy is currently in use. Virtually all CALR mutations identified in PMF are small insertions or deletions clustered within exon 9 leading to a neo-epitope peptide sequence which is thought to directly or indirectly activate the thrombopoietin receptor (TpoR) by a poorly defined mechanism. Here we engineered a neo-epitope specific monoclonal antobody that has striking biological activity against ruxolitinib persistent cells. Methods TF-1 TpoR cells expressing TpoR were supplemented with 20 ng/mL of TPO. Rats were immunised with a CALR mutant peptide coupled to KLH. Serum from the immunised rats was screened by enzyme linked immunoassay, to verify a strong titre to the peptide immunogen. Primary PMF CD34+ cells were cultured in StemCell Pro with human SCF, IL-6 and IL-9. NSG mice were used to for engraftment studies after 150 cGy irradiation. Results: We engineered a panel of rat monoclonal antibodies after immunization with a 30 amino acid peptide corresponding to the C-terminal mutant CALR neoepitope sequence with an extra cysteine residue. Clone 4D7 showed superior activity of detecting mutant but not wild type CALR protein with a binding affinity of 13.5 pM and dissociation constant of 1.53 nM as measured by I 125-Scatchard. Treatment with 4D7 resulted in a significant (5-7-fold) increase in the amount of full-length mutant CALR protein in conditioned media. 4D7 inhibited Tpo-independent cell growth over 6 days in TF-1 cells expressing MPL and mutant CALR at 2, 10 and 20 µg. 4D7 blocked constitutive factor-independent phospho-STAT5 and phospho-ERK after incubation exclusively in mutant CALR cells but not in TF-1 cells expressing TpoR alone and increased the sub-G 0 fraction was observed compared to IgG control (P = 0.001, n = 3 independent experiments) consistent with induction of an apoptotic response. We tested activity in purified primary CD34+ cells obtained from patients with CALR mutant myelofibrosis using two orthogonal assays: - (i) Tpo-independent megakaryocyte differentiation in liquid culture and (ii) Tpo-independent megakaryocyte colony formation on a collagen-based medium. 4 out of 4 patient samples that displayed robust Tpo-independent growth of CD41+CD61+ megakaryocyte progenitors showed inhibition by 4D7 of at least 50%. Similarly, we saw dramatic reduction in the absolute numbers of primary Tpo-independent megakaryocyte colonies cultured on collagen (colony-forming unit-mega) treated with 4D7 in multiple patient samples (decrease of 46%, P = 0.0001, Student's t-test, n = 4 independent patient samples) Importantly, secretion of mutant CALR protein was neither upregulated nor downregulated by ruxolitinib, indicating ruxolitinib is unlikely to alter mutant CALR trafficking in patients. 4D7 had strong inhibitory activity on cells that were resistant to ruxolitinib, in both liquid culture at 96 hours or colony formation. To test whether 4D7 could block mutant CALR-dependent proliferation in vivo, we developed two distinct xenograft models, a bone marrow engraftment model, which measures mutant CALR dependent proliferation in the bone marrow microenvironment, and a chloroma model, which mimics extravascular infiltration of mutant CALR leukaemia, by injection of TPO-independent TF-1 cells in NSG mice. In the bone marrow engraftment model 4D7 treatment (12 mg/kg twice weekly via intraperitoneal injection) lowered peripheral blood engraftment of human CD33 myeloid cells at 3 weeks, bone marrow engraftment and significantly prolonged survival compared to IgG control (P=0.004, HR=0.2). In the chloroma model, 4D7 treatment resulted in significant decrease in tumour growth measured at 3 weeks (P<0.01) and improved overall survival (P=0.02, HR=0.07) compared to IgG control Conclusion: Together, these results suggest an immunotherapeutic approach may have clinical utility CALR-driven myeloproliferative neoplasms and CALR mutant acute myeloid leukaemia, as well as activity in CALR mutant patients that develop resistance/persistence to ruxolitinib. Disclosures Ross: Bristol Myers Squib: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Keros Therapeutics: Consultancy, Honoraria. Reinisch: Celgene: Research Funding; Pfizer: Consultancy.

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