Identification of a First-in-Class PRMT5 Inhibitor with Potent in Vitro and in Vivo Activity in Preclinical Models of Mantle Cell Lymphoma

Abstract Protein Arginine Methyltransferase-5 (PRMT5) has been reported to play a role in multiple diverse cellular processes including tumorigenesis. Overexpression of PRMT5 has been demonstrated in cell lines and primary patient samples derived from lymphomas, particularly Mantle Cell Lymphoma (MCL). Furthermore, knockdown of PRMT5 expression inhibits the proliferation of MCL cell lines. The mechanisms behind the oncogenic potential of PRMT5 are unclear, but the protein has been postulated to regulate processes such as cell death, cell cycle progression, and RNA processing through the dimethylation of arginine residues within a variety of cytoplasmic and nuclear target proteins. Epizyme developed small molecule inhibitors of PRMT5 enzyme activity in order to understand the role of PRMT5-mediated arginine methylation in tumorigenesis and to develop PRMT5-targeted cancer therapeutics. Here, we describe the identification and characterization of a potent and selective inhibitor of PRMT5 with anti-proliferative effects in both in vivo and in vitro models of MCL. A diverse compound library was screened for inhibitors of arginine methylation by purified recombinant PRMT5:MEP50 complex and multiple hits were identified. The inhibitors are SAM uncompetitive, peptide competitive and bind with the PRMT5:MEP50 complex in a unique binding mode not previously observed. Further optimization yielded YQ36286, an orally available inhibitor of PRMT5 with enzymatic activity in biochemical assays with an IC50 in the low nM range and broad selectivity against a panel of other histone methyltransferases. YQ36286 demonstrated potent cellular activity as measured by its ability to inhibit symmetric dimethylation of SmD3, a cytoplasmic PRMT5 substrate in a time- and concentration-dependent manner. Treatment of MCL cell lines with YQ36286 led to inhibition of SmD3 methylation and cell killing, with IC50s in the nM range. Oral dosing of YQ36286 demonstrated dose-dependent anti-tumor activity in multiple MCL xenograft models. In xenograft studies with the Z138 MCL cell line, near 95% tumor growth inhibition was observed after 21 days of dosing with a corresponding decrease in symmetrically dimethylated levels of PRMT5 substrates. In summary, we have developed the first potent and selective small molecule inhibitor of PRMT5 that has cellular activity and in vivo efficacy. MCL cells are dependent on PRMT5 activity for their survival as demonstrated with YQ36286. This small molecule represents a starting point for the development of PRMT5 inhibitors as potential cancer therapeutics. Disclosures Penebre: Company stock options: Equity Ownership; Epizyme Inc.: Employment; GSK Research Funding: Research Funding. Kuplast:GSK research funding: Research Funding; Company Stock options: Equity Ownership; Epizyme Inc.: Employment. Majer:Epizyme Inc.: Employment; Company Stock options: Equity Ownership; GSK research funding: Research Funding. Johnston:Epizyme Inc.: Employment; Company Stock options: Equity Ownership; GSK research funding: Research Funding. Rioux:Epizyme Inc.: Employment; Company Stock options: Equity Ownership; GSK research funding: Research Funding. Munchhof:Epizyme Inc.: Employment; GSK research funding: Research Funding. Jin:Epizyme Inc.: Employment; GSK research funding: Research Funding; Company stock options: Equity Ownership. Boriak-Sjodin:Epizyme Inc.: Employment; Company Stock options: Equity Ownership; GSK research funding: Research Funding. Wigle:Epizyme Inc.: Employment; Company Stock options: Equity Ownership; GSK research funding: Research Funding. Jacques:Epizyme Inc.: Employment; Company Stock options: Equity Ownership; GSK research funding: Research Funding. West:Epizyme Inc.: Employment; Company Stock options: Equity Ownership; GSK research funding: Research Funding. Lingaraj:Epizyme Inc.: Employment; Company Stock options: Equity Ownership; GSK research funding: Research Funding. Stickland:GSK research funding: Research Funding; Company Stock options: Equity Ownership; Epizyme Inc.: Employment. Ribich:Epizyme Inc.: Employment; Company Stock options: Equity Ownership; GSK research funding: Research Funding. Raimondi:Epizyme: Employment, Equity Ownership; Company Stock options: Equity Ownership; GSK research funding: Research Funding. Porter-Scott:Company stock options: Equity Ownership; GSK research funding: Research Funding; Epizyme Inc.: Employment. Waters:Epizyme, Inc: Employment, Equity Ownership; GSK research funding: Research Funding. Pollock:Epizyme: Employment, Equity Ownership; GSK research funding: Research Funding. Smith:GSK research funding: Research Funding; Epizyme: Employment, Equity Ownership. Barbash:GlaxoSmithKline Pharmaceuticals: Employment. Kruger:GlaxoSmithKline Pharmaceuticals: Employment, Equity Ownership. Copeland:Mersana: Membership on an entity's Board of Directors or advisory committees; Epizyme, Inc: Employment, Equity Ownership; Celgene, Inc: Research Funding; Eisai Inc: Research Funding; Glaxo Smith Kline, Inc: Research Funding; Multiple Myeloma Research Foundation: Research Funding; Leukemia and Lymphoma Society: Research Funding; New Enterprise Associates: Ad hoc consultant, Ad hoc consultant Other. Moyer:Epizyme Inc.: Employment; Company Stock options: Equity Ownership; GSK research funding: Research Funding. Chesworth:Epizyme Inc.: Employment; Company Stock options: Equity Ownership; GSK research funding: Research Funding. Duncan:Epizyme Inc.: Employment; Company Stock options: Equity Ownership; GSK research funding: Research Funding.

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ASLAN003, a Novel and Potent Dihydroorotate Dehydrogenase (DHODH) Inhibitor, Induces Differentiation of Acute Myeloid Leukemia

Blood ◽

10.1182/blood-2018-99-114392 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 4047-4047 ◽

Cited By ~ 1

Author(s):

Jianbiao Zhou ◽

Jessie Yiying Quah ◽

Jing Yuan Chooi ◽

Sabrina Hui-Min Toh ◽

Yvonne Ng ◽

...

Keyword(s):

Cell Growth ◽

Cell Lines ◽

Research Funding ◽

Tissue Bank ◽

Dihydroorotate Dehydrogenase ◽

Employment Equity ◽

Healthy Control ◽

Equity Ownership ◽

Nbt Reduction

Abstract Background: Differentiation therapies achieve remarkable success in acute promyelocytic leukemia (APL), a subtype of acute myeloid leukemia (AML). However, clinical benefits of differentiation therapies are negligible in non-APL AML, which accounts for the majority of AML cases. Dihydroorotate dehydrogenase (DHODH) regulates the fourth step of the de novo pyrimidine synthesis pathway. DHODH is a key therapeutic target for auto-immune diseases and cancer, particularly differentiation of AML. ASLAN003 is a novel, potent small molecule DHODH inhibitor being developed in AML by ASLAN Pharmaceuticals. Methods: We investigated activity of ASLAN003 in AML cell lines and primary bone marrow (BM) cells (NUS Leukemia Tissue Bank) from patients with AML (N = 14) or myelodysplastic syndromes (MDS) (N = 6) and healthy control (N = 1). We performed CTG assay, FACS analysis of cell viability and myeloid markers, wright-giemsa staining, NBT reduction assay, and qRT-PCR analysis of key lineage transcription factors to evaluate the effects of ASLAN003 on cell growth, differentiation, apoptosis, and gene expression changes in vitro. Two AML cell lines and 1 leukemic patient derived xenograft (PDX) line (NUS Leukemia Tissue Bank) were studied in NSG xenograft mice. Mice were administrated with vehicle control or ASLAN003 50 mg/kg by oral gavage once daily. Results: ASLAN003 inhibited leukemic cell growth of THP-1, MOLM-14 and KG-1 with IC50 of 152, 582 and 382 nM, respectively, at 48 h. Treatment of these leukemia cells with ASLAN003 for 96 h consistently resulted in remarkable increase of CD11b (p < 0.001) and displayed morphologic changes of terminal differentiation and positivity for NBT reduction. ASLAN003 was active in differentiation with an EC50 of 28, 85, and 56 nM, in these 3 lines, respectively. ASLAN003 induced approximately 2-fold higher CD11b+ cells than Brequinar (BRQ), another DHODH inhibitor. Addition of uridine rescued differentiation and improved cell viability in ASLAN003 treated-cells, implying on-target specificity of ASLAN003. Mechanistically, ASLAN003 induced differentiation through induction of myeloid lineage transcription factor Runx1, Pu.1, Gif1 and repression of HoxA9, Gata1. The response of primary BM cells to ASLAN003 was classified into 3 categories: sensitive if any of myeloid markers CD11b, CD14, CD13 or CD33 increased ≥ 15%; moderate: ≥ 5%, but < 15%; resistant: < 5%. Among AML samples, we observed 6 (43%) sensitive cases, 6 (43%) moderate cases and 2 (14%) resistant cases. Three (50%) MDS samples displayed sensitive response and 3 cases (50%) showed moderate response. The healthy control sample was resistant to ASLAN003. Importantly, ASLAN003 promoted differentiation and cell death of myeloid cells in one relapsed AML case. Morphologic analysis and NBT assay demonstrated the features of neutrophil differentiation in selected ASLAN003-treated primary AML blasts. For in vivo experiments, significantly prolonged survival was seen in ASLAN003-treated groups when compared to vehicle control group in both MOLM-14 (p = 0.031) and THP-1 (p < 0.001) xenograft models. ASLAN003 substantially reduced disseminated tumors and leukemic infiltration into liver in xenografted mice. The human CD45+ cells were significantly reduced in BM, peripheral blood, spleen and liver, with significantly increased differentiation of AML cells (CD11b and CD14 positive cells) in BM of treated mice in both models (p < 0.01). We also evaluated the therapeutic efficacy of ASLAN003 in one PDX line, AML-14. At the end of experiments (day 77 post treatment), all PDX mice were alive in both control and ASLAN003 group. The leukemic burden was significantly lower in ASLAN003-treated PDXs than in vehicle-treated PDXs (p = 0.04). Overall, these data demonstrate potent in vivo efficacy of ASLAN003 in inducing myeloid differentiation of blast cells and the drug appears highly tolerable even after prolonged administration. Conclusion: ASLAN003 is a novel, highly potent DHODH inhibitor that induces terminal differentiation, inhibits cell growth and promotes cell death of AML blasts, including relapsed AML blasts. ASLAN003 prolongs survival and shows therapeutic effects in mice bearing different AML cell lines and reduces leukemic burden in an AML PDX model. Currently, ASLAN003 efficacy is being evaluated in a Phase IIa clinical trial in patients with AML (NCT03451084; Ting, ASH abstract 2018). Disclosures Seet: ASLAN Pharmaceuticals: Employment, Equity Ownership. Ooi:ASLAN Pharmaceuticals: Employment, Equity Ownership. Lindmark:ASLAN Pharmaceuticals: Employment, Equity Ownership. McHale:ASLAN Pharmaceuticals: Employment, Equity Ownership. Chng:Amgen: Consultancy, Honoraria, Other: Travel, accommodation, expenses; Aslan: Research Funding; Merck: Research Funding; Janssen: Consultancy, Honoraria, Other: Travel, accommodation, expenses, Research Funding; Takeda: Consultancy, Honoraria, Other: Travel, accommodation, expenses; Celgene: Consultancy, Honoraria, Other: Travel, accommodation, expenses, Research Funding.

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Alvocidib Potentiates the Activity of Venetoclax in Preclinical Models of Acute Myeloid Leukemia

Blood ◽

10.1182/blood.v128.22.1652.1652 ◽

2016 ◽

Vol 128 (22) ◽

pp. 1652-1652

Author(s):

Clifford J. Whatcott ◽

James M Bogenberger ◽

Wontak Kim ◽

Hillary Haws ◽

Nanna Hansen ◽

...

Keyword(s):

Clinical Trials ◽

Cell Viability ◽

Cell Lines ◽

Research Funding ◽

Single Agent ◽

Employment Equity ◽

Fold Reduction ◽

Remission Rates ◽

Equity Ownership

Abstract Introduction Venetoclax (ABT-199) is an approved BCL-2 inhibitor for the treatment of patients with chronic lymphocytic leukemia (CLL). Multiple clinical trials are underway to explore its efficacy in additional indications. While venetoclax demonstrated high remission rates in combination with azacitidine in early stage clinical trials, the question of durability of responses and primary and acquired resistance remain, especially given the modest activity and rapid development of resistance as a single agent. One reported mechanism of intrinsic resistance is high expression of other BCL-2 family proteins, including MCL-1. We and others have demonstrated that the CDK9 inhibitor, alvocidib, can mediate transcriptional repression of anti-apoptotic MCL-1. It has also been shown that alvocidib can increase pro-apoptotic BIM, a dual activator and sensitizer BH3-only protein that can directly induce apoptosis and simultaneously inactivate anti-apoptotic BCL-2 family proteins such as MCL-1 and BCL-2, thus having the same effect on mitochondria-associated apoptosis as MCL-1 down-regulation, with the potential to directly induce apoptosis. An alvocidib-containing cytotoxic chemotherapy regimen demonstrated favorable remission rates in high-risk AML patients over standard therapy in a randomized Phase 2 trial indicating its potential role and safety in AML. We hypothesized that alvocidib and venetoclax would synergize against AML cells by shifting the overall balance of pro- and anti-apoptotic BCL-2 proteins in favor of apoptosis and thus represent a novel active treatment regimen in AML. Aims This study seeks to examine the efficacy of a treatment regimen containing alvocidib and venetoclax in multiple preclinical studies, including in vivo models of AML. Methods Cell viability assays interrogating alvocidib and venetoclax activity in cell lines were performed using CellTiter-Glo according to manufacturer's protocol. mRNA/miRNA expression changes were assessed using standard RT-PCR technique. Protein expression changes were assessed using standard western immunoblotting technique. To assess the efficacy of an alvocidib and venetoclax combination on tumor growth in an in vivo model, the OCI-AML3 xenograft mouse model and ex vivo studies with AML patient samples were performed. Results Herein we demonstrate that alvocidib inhibits both mRNA and protein expression of MCL-1 in a time and concentration-dependent fashion in 3 out of 4 AML cell lines analyzed, while in cells where alvocidib did not reduce MCL-1 protein levels (i.e. MOLM-13) a dose-dependent decrease in miR17-92, and concomitant increase in BIM protein was observed after 24 hours of alvocidib treatment. The alvocidib-venetoclax combination resulted in very strong synergistic reductions of cell viability (with combination indices [CI] of 0.4 to 0.7), both in venetoclax-sensitive and resistant cells. The venetoclax-sensitive lines, MV4-11 and MOLM-13, exhibited 5- to 10-fold reduction of venetoclax EC50 values in the low nM range when combined with only 80 nM alvocidib. Importantly, venetoclax-resistant lines, OCI-AML3 and THP-1, exhibited at least 20-fold reduction of venetoclax EC50 values from near 1 µM to 10-50 nM, when combined with 80 nM alvocidib.In the venetoclax-resistant OCI-AML3 xenograft model, single agent alvocidib and venetoclax achieved tumor growth inhibition (TGI) of 9.7 and 31.5%, respectively, while the combination achieved 87.9% TGI at the same dose levels of individual drugs. Conclusions Taken together, our data suggest that the combination of alvocidib with venetoclax is highly synergistic in vitro and in vivo, in both venetoclax-sensitive and -resistant AML across a heterogeneous genomic background. The particularly high level of synergy achieved in venetoclax-resistant cell lines highlights the central importance of both BCL-2 and MCL-1-mediated cell survival in AML. Importantly, the addition of alvocidib to venetoclax treatment reduced IC50s to clinically achievable concentrations. Therefore, we conclude that an alvocidib/venetoclax combination may be a novel approach for the treatment of AML and warrants further pre-clinical and clinical validation. Disclosures Whatcott: Tolero Pharmaceuticals: Employment. Kim:Tolero Pharmaceuticals: Employment. Haws:Tolero Pharmaceuticals: Employment. Mesa:Celgene: Research Funding; Galena: Consultancy; Promedior: Research Funding; Ariad: Consultancy; Novartis: Consultancy; CTI: Research Funding; Incyte: Research Funding; Gilead: Research Funding. Peterson:Tolero Pharmaceuticals: Employment. Siddiqui-Jain:Tolero Pharmaceuticals: Employment. Weitman:Tolero Pharmaceuticals: Employment. Bearss:Tolero Pharmaceuticals: Employment, Equity Ownership, Patents & Royalties. Warner:Tolero Pharmaceuticals: Employment, Equity Ownership, Patents & Royalties.

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Diffuse Large B Cell Lymphoma (DLBCL) Expresses ROR1 and a ROR1 Small Molecule Inhibitor (KAN0441571C) Induced Significant Apoptosis of Tumor Cells

Blood ◽

10.1182/blood-2019-126801 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 2565-2565

Author(s):

Mohammad Hojjat-Farsangi ◽

Amineh Ghaderi ◽

AmirHossein Daneshmanesh ◽

Jemina Lehto ◽

Ali Moshfegh ◽

...

Keyword(s):

Cell Lines ◽

Small Molecule ◽

Stromal Cells ◽

Research Funding ◽

Cytotoxic Effect ◽

Advanced Disease ◽

Annexin V ◽

Employment Equity ◽

2Nd Generation ◽

Equity Ownership

Background: Receptor tyrosine kinase (RTK) (ROR1) is normally expressed during embryogenesis but absent in most normal tissues. However, ROR1 is overexpressed in several cancers (onco-fetal RTK) and of importance for various tumor cell functions such as proliferation and survival. In patients with diffuse large B-cell lymphomas (DLBCL) there is a great medical need to develop new treatment alternatives for those not responding to primary treatment as well as for patients with relapse as effective treatments are warranted. Inhibition of ROR1 by a small molecule ROR1 inhibitor (KAN0439834) abrogated downstream kinase activities as well as induced apoptosis of various tumor cells as CLL and pancreatic carcinoma (Leukemia, Oct;32(10):2291-2295, 2018) (PLoS One. 13(6): e0198038, 2018). A 2nd generation of ROR1 inhibitor (KAN0441571C) has been synthesized with the aim to bind to the ROR1-TK domain and inhibit ROR1 signaling. Aim: To examine the expression of ROR1 in DLBCL cell lines (RC-KB, SUDHL4, MS, OCL-LY3, U2932) and in patients´ samples at different stages of DLBCL as well as effects of KAN0441571C on survival of DLBCL cells and ROR1 signaling. Methods: Flow cytometry, tissue microarray and immunohistochemistry assays were used to check ROR1 expression. MTT and Annexin V/PI assays were applied to analyse cytotoxicity and apoptosis of KAN0441571C alone or in combination with ibrutinib (BTK inhibitor) and venetoclax (BCL-2 inhibitor) on DLBCL cell lines. Western blot was performed to evaluate ROR1 phosphorylation and associated signaling pathways. DLBCL cells were also cultured with HS-5 stromal cells (ROR1 neg.) to evaluate the apoptosis inhibitory effects of stromal cells. Results: ROR1 expression was significantly more frequently noted in patients with advanced disease (Richter´s, transformation, transformed follicular lymphoma and refractory DLBCL) compared to less advanced disease (recurrent or de novo DLBCL) (p=0.0001). In primary refractory and relapsing DLBCL 5-years survival was 45% in ROR1- patients (n=17) while in ROR1+ patients (n=16) the corresponding figure was <10% (p= 0.0335). KAN0441571C induced a dose-dependent cytotoxic effect in all ROR1+ DLBCL cell lines (EC50=50-100 nM) while no effect could be noted in the ROR1- U2932 cell line (EC50>10000 nM). EC50 for venetoclax in the ROR1+ DLBCL cell lines varied between 100 and 500 and 5000 - 10000 nM for ibrutinib. In comparison to venetoclax, KAN0441571C induced a similar or significantly higher cytotoxic effect. KAN0441571C and venetoclax seemed to be the most promising drug combination approaching 100% killing at the EC50 dose for each drug. Apoptosis was confirmed by Annexin V/PI staining as well as by downregulation of BCL-2 and MCL-1 as well as cleavage of PARP and caspase 3. KAN0441571C dephosphorylated ROR1 as well as the co-receptor LRP6 and the SRC protein which binds to phosphorylated ROR1. The downstream molecules PI3Kδ/AKT/mTOR was also dephosphorylated and the transcription factor CREB. CK1δ and GSK3B were also dephosphorylated and β-catenin downregulated indicating involvement of both the non-canonical and canonical Wnt pathways. When DLBCL and HS-5 cells (ROR1 neg.) were co-cultured, HS-5 cells could partially prevent induction of apoptosis of DLBCL cells at low concentrations of KAN0441571C, while at higher concentrations the presence of stromal cells was less effective. Zebrafish embryos transplanted with the OCI-Ly3 cell line were treated for 3 days with KAN0441571C (25-1000 nM). No toxic effects of the drug could be noted. A significant dose and time-dependent decrease in the tumor area were noted. Conclusion: KAN0441571C is the 2nd generation of a novel class of ROR1-inhibiting small molecule drugs. The molecule was more effective in inducing apoptosis of DCBCL cells than venetoclax or ibrutinib. New anti-cancer drugs with other mechanisms of action than those clinically available for DLBCL are warranted to improve the prognosis. ROR1 inhibitors in combination with other targeted drugs as venetoclax and ibrutinib might improve the therapeutic effects. KAN0441571C may be a novel drug candidate which needs further exploration in DLBCL. Disclosures Lehto: Kancera AB: Employment. Vågberg:Kancera AB: Employment. Olsson:Kancera AB: Employment. Löfberg:Kancera AB: Employment. Norström:Kancera AB: Employment. Schultz:Kancera AB: Employment, Equity Ownership. Norin:Kancera AB: Employment. Olin:Kancera AB: Employment, Equity Ownership. Österborg:Kancera AB: Research Funding; Janssen: Research Funding; Abbvie: Research Funding; Gilead: Research Funding; BeiGene: Research Funding. Mellstedt:Kancera AB: Consultancy, Equity Ownership, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.

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ROR1 Small Molecule Inhibitor (KAN0441571C) Induced Significant Apoptosis of Mantle Cell Lymphoma (MCL) Cells

Blood ◽

10.1182/blood-2019-129773 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 5312-5312 ◽

Cited By ~ 1

Author(s):

Håkan Mellstedt ◽

Amineh Ghaderi ◽

Johanna Aschan ◽

Fariba Mozaffari ◽

Ali Moshfegh ◽

...

Keyword(s):

Flow Cytometry ◽

Tyrosine Kinase ◽

Cell Lines ◽

Small Molecule ◽

Research Funding ◽

Second Generation ◽

Small Molecule Inhibitor ◽

Employment Equity ◽

Molecule Inhibitor ◽

Equity Ownership

Background: ROR1 - a receptor tyrosine kinase (RTK) - is essential for normal embryonic development, but is absent on most normal adult tissues. ROR1 is of importance of cell proliferation, differentiation, survival and metabolism. However, ROR1 is overexpressed in several types of cancer (onco-fetal RTK). MCL is an aggressive and incurable non-Hodgkin lymphoma characterized by translocation (11;14) (q13;q32) and cyclin D overexpression. ROR1 has been described to be highly expressed in MCL cells. We have previously presented results on a small molecule ROR1 inhibitor in CLL (KAN0439834) (Leukemia 32(10):2291, 2018). A second generation ROR1 inhibitor, KAN0441571C, has been developed with improved killing of tumor cells and with longer half-life time (>10h) (PK studies in mice/rats/dogs) compared to KAN0439834. Aim: In this study we examined effects of the ROR1 small molecule inhibitor KAN0441571C in human MCL cells (Granta-519, Jeko-1, JVM-2, Z138, Mino) as part of a pre-clinical evaluation. Methods: ROR1 expression was evaluated by flow cytometry and WB. Cytotoxicity was analysed by MTT and apoptosis by Annexin V/P staining and Western Blot for apoptotic proteins. Cytotoxicity (MTT) was also analysed by combining the ROR1 inhibitor with ibrutinib, acalabrutinib, venetoclax and bendamustine. Effects of KAN0441571C on ROR1 inactivation (dephosphorylation) and signaling pathways were evaluated by WB. Results: All five cell-lines expressed phosphorylated ROR1 (130 kDa) with a varying intensity. Surface expression (flow-cytometry) varied from 0% (JVM-2) to 100% (Mino and JeKo-1). The data indicate expression of also splice variants lacking the extracellular domain. KAN0441571C induced time and dose dependent apoptosis of the five MCL cell-lines which was p53 independent. EC50 varied between 100-250 nM (24h). Apoptosis was confirmed by cleavage of caspase 3 and PARP as well as down-regulation of the MCL-1 and BCL-2 proteins. Moreover, ROR1 was dephosphorylated by KAN0441571C. Downstream of ROR1 both the Wnt canonical and non-canonical pathways were inactivated depending on the cell line. KAN0441571C had in most cell lines a similar cytotoxic effect as ibrutinib, acalabrutinib and venetoclax while bendamustine was inferior. KAN0441571C had an additive effect to ibrutinib, acalabrutinib and venetoclax respectively and KAN0441571C in combination with either of these three agents induced a complete killing of the cell lines. Conclusions: KAN0441571C is a second generation of a novel class of ROR1-tyrosine kinase inhibitor. This small molecule was effective in inducing apoptosis of MCL cells with other mechanisms of action than for drugs in clinical use for MCL. Combination of KAN0441571C with other MCL targeting drugs induced a complete killing of the tumor cell population in a preclinical in vitro model. Our results support the further development of ROR1 small molecule inhibitors as a new therapeutic principle in MCL as well as in other B-cell malignancies with an additive effect to existing targeted therapeutics. Disclosures Schultz: Kancera AB: Employment, Equity Ownership. Norin:Kancera AB: Employment. Olin:Kancera AB: Employment, Equity Ownership. Österborg:Janssen: Research Funding; Kancera AB: Research Funding; BeiGene: Research Funding; Abbvie: Research Funding; Gilead: Research Funding.

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Phenotype Does Not Always Equal Function: HDAC Inhibitors and UM171, but Not SR1, Lead to Rapid Upregulation of CD90 on Non-Engrafting CD34+CD90-Negative Human Cells

Blood ◽

10.1182/blood.v130.suppl_1.659.659 ◽

2017 ◽

Vol 130 (Suppl_1) ◽

pp. 659-659

Author(s):

Kevin A. Goncalves ◽

Megan D. Hoban ◽

Jennifer L. Proctor ◽

Hillary L. Adams ◽

Sharon L. Hyzy ◽

...

Keyword(s):

In Vitro Culture ◽

Small Molecule ◽

Hdac Inhibitors ◽

Employment Equity ◽

Nsg Mice ◽

Cd34 Cells ◽

Equity Ownership ◽

Human Hscs

Abstract Background. The ability to expand human hematopoietic stem cells (HSCs) has the potential to improve outcomes in HSC transplantation and increase the dose of gene-modified HSCs. While many approaches have been reported to expand HSCs, a direct comparison of the various methods to expand transplantable HSCs has not been published and clinical outcome data for the various methods is incomplete. In the present study, we compared several small molecule approaches reported to expand human HSCs including HDAC inhibitors, the aryl hydrocarbon antagonist, SR1, and UM171, a small molecule with unknown mechanism, for the ability to expand phenotypic HSC during in vitro culture and to expand cells that engraft NSG mice. Although all strategies increased the number of phenotypic HSC (CD34+CD90+CD45RA-) in vitro, SR1 was the most effective method to increase the number of NOD-SCID engrafting cells. Importantly, we found that HDAC inhibitors and UM171 upregulated phenotypic stem cell markers on downstream progenitors, suggesting that these compounds do not expand true HSCs. Methods. Small-molecules, SR1, HDAC inhibitors (BG45, CAY10398, CAY10433, CAY10603, Entinostat, HC Toxin, LMK235, PCI-34051, Pyroxamide, Romidepsin, SAHA, Scriptaid, TMP269, Trichostatin A, or Valproic Acid) and UM171 were titrated and then evaluated at their optimal concentrations in the presence of cytokines (TPO, SCF, FLT3L, and IL6) for the ability to expand human mobilized peripheral blood (mPB)-derived CD34+ cells ex vivo . Immunophenotype and cell numbers were assessed by flow cytometry following a 7-day expansion assay in 10-point dose-response (10 µM to 0.5 nM). HSC function was evaluated by enumeration of colony forming units in methylcellulose and a subset of the compounds were evaluated by transplanting expanded cells into sub-lethally irradiated NSG mice to assess engraftment potential in vivo . All cells expanded with compounds were compared to uncultured or vehicle-cultured cells. Results. Following 7 days of expansion, SR1 (5-fold), UM171 (4-fold), or HDAC inhibitors (>3-35-fold) resulted in an increase in CD34+CD90+CD45RA- number relative to cells cultured with cytokines alone; however, only SR1 (18-fold) and UM171 (8-fold) demonstrated enhanced engraftment in NSG mice. Interestingly, while HDAC inhibitors and UM171 gave the most robust increase in the number and frequency of CD34+CD90+CD45RA- cells during in vitro culture, these methods were inferior to SR1 at increasing NSG engrafting cells. The increase in CD34+CD90+CD45RA- cells observed during in vitro culture suggested that these compounds may be generating a false phenotype by upregulating CD90 and down-regulating CD45RA on progenitors that were originally CD34+CD90-CD45RA+. We tested this hypothesis by sorting CD34+CD90-CD45RA+ cells and culturing these with the various compounds. These experiments confirmed that both HDAC inhibitors (33-100 fold) and UM171 (28-fold) led to upregulation of CD90 on CD34+CD90-CD45RA+ cells after 4 days in culture. Since approximately 90% of the starting CD34+ cells were CD90-, these data suggest that most of the CD34+CD90+CD45RA- cells in cultures with HDAC inhibitors and UM171 arise from upregulation of CD90 rather than expansion of true CD34+CD90+CD45RA- cells and may explain the disconnect between in vitro HSC phenotype and NSG engraftment in vivo . This was further confirmed by evaluation of colony forming unit frequency of CD34+CD90-CD45RA+ cells after culture with compounds. Conclusions. We have showed that AHR antagonism is optimal for expanding functional human HSCs using the NSG engraftment model. We also demonstrated that UM171 and HDAC inhibitors upregulate phenotypic HSC markers on downstream progenitors. This could explain the discrepancy between impressive in vitro phenotypic expansion and insufficient functional activity in the NSG mouse model. Therefore, these data suggest caution when interpreting in vitro expansion phenotypes without confirmatory functional transplantation data, especially as these approaches move into clinical trials in patients. Disclosures Goncalves: Magenta Therapeutics: Employment, Equity Ownership. Hoban: Magenta Therapeutics: Employment, Equity Ownership. Proctor: Magenta Therapeutics: Employment, Equity Ownership. Adams: Magenta Therapeutics: Employment, Equity Ownership. Hyzy: Magenta Therapeutics: Employment, Equity Ownership. Boitano: Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties. Cooke: Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties.

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Differential Effects of Milatuzumab On Human Antigen-Presenting Cells in Comparison to Malignant B Cells.

Blood ◽

10.1182/blood.v114.22.2744.2744 ◽

2009 ◽

Vol 114 (22) ◽

pp. 2744-2744

Author(s):

Xiaochuan Chen ◽

Rhona Stein ◽

Chien-Hsing Chang ◽

David M. Goldenberg

Keyword(s):

T Cell ◽

B Cells ◽

Cell Lines ◽

Hairy Cell ◽

Employment Equity ◽

Cross Presentation ◽

Equity Ownership ◽

Antigen Presenting

Abstract Abstract 2744 Poster Board II-720 Introduction: The humanized anti-CD74 monoclonal antibody (mAb), milatuzumab, is in clinical evaluation as a therapeutic mAb for non-Hodgkin lymphoma, chronic lymphocytic leukemia (CLL), and multiple myeloma after preclinical evidence of activity in these tumor types. In addition to its expression in malignant cells, CD74 is also expressed in normal B cells, monocytes, macrophages, Langerhans cells, follicular and blood dendritic cells. A question therefore arises whether milatuzumab is toxic to or affects the function of these immune cells. This has important implications, not only for safe therapeutic use of this mAb, but also for its potential application as a novel delivery modality for in-vivo targeted vaccination. Methods: We assessed the binding profiles and functional effects of milatuzumab on human antigen-presenting cell (APC) subsets. Studies on the effect of milatuzumab on antigen presentation and cross-presentation are included. In addition, binding and cytotoxicity on a panel of leukemia/lymphoma cell lines and CLL patient cells were tested to demonstrate the range of malignancies that can be treated with this mAb. Results: Milatuzumab bound efficiently to different subsets of blood dendritic cells, including BDCA-1+ myeloid DCs (MDC1), BDCA-2+ plasmacytoid DCs (PDC), BDCA-3+ myeloid DCs (MDC2), B lymphocytes, monocytes, and immature DCs derived from human monocytes in vitro, but not LPS-matured DCs, which correlated well with their CD74 expression levels. In the malignant B-cells tested, milatuzumab bound to the surface of 2/3 AML, 2/2 mantle cell (MCL), 4/4 ALL, 1/1 hairy cell leukemia, 2/2 CLL, 7/7 NHL, and 5/6 multiple myeloma cell lines, and cells of 4/6 CLL patient specimens. Significant cytotoxicity (P<0.05) was observed in 2/2 MCL, 2/2 CLL, 3/4 ALL, 1/1 hairy cell, 2/2 NHL, and 2/2 MM cell lines, and 3/4 CD74-positive CLL patient cells, but not in the AML cell lines following incubation with milatuzumab. In contrast, milatuzumab had minimal effects on the viability of DCs or B cells that normally express CD74. The DC maturation and DC-mediated T-cell functions were not altered by milatuzumab treatment, which include DC-induced T-cell proliferation, CD4+CD25+FoxP3+ Treg expansion, and CD4+ naïve T-cell polarization. Moreover, milatuzumab had little effect on CMV-specific CD8- and CD8+ T cell interferon-g responses of peripheral blood mononuclear cells stimulated in vitro with CMV pp65 peptides or protein, suggesting that milatuzumab does not influence antigen presentation or cross-presentation. Conclusion: These results demonstrate that milatuzumab is a highly specific therapeutic mAb against B-cell malignancies with potentially minimal side effects. It also suggests that milatuzumab may be a promising novel delivery mAb for in vivo targeted vaccinations, given its efficient binding, but lack of cytotoxicity and functional disruption on CD74-expressing normal APCs. (Supported in part by NIH grant PO1-CA103985.) Disclosures: Chang: Immunomedics Inc.: Employment, Equity Ownership, Patents & Royalties. Goldenberg:Immunomedics, Inc.: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties.

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Phase II Study of the Cyclin-Dependent Kinase (CDK) Inhibitor Dinaciclib (SCH 727965) In Patients with Advanced Acute Leukemias

Blood ◽

10.1182/blood.v116.21.3287.3287 ◽

2010 ◽

Vol 116 (21) ◽

pp. 3287-3287 ◽

Cited By ~ 5

Author(s):

Ivana Gojo ◽

Alison Walker ◽

Maureen Cooper ◽

Eric J Feldman ◽

Swaminathan Padmanabhan ◽

...

Keyword(s):

Research Funding ◽

Post Treatment ◽

Parp Cleavage ◽

Employment Equity ◽

Acute Leukemias ◽

Early Management ◽

Tumor Lysis ◽

Equity Ownership ◽

Pre Treatment

Abstract Abstract 3287 Background: Dinaciclib is a potent and selective inhibitor of the CDKs 1, 2, 5, and 9 that has demonstrated anti-tumor activity against both myeloid and lymphoid leukemia cell lines in vitro and human tumor xenografts in vivo. Methods: A randomized, multicenter, open-label phase 2 study of dinaciclib 50 mg/m2 administered by 2-hour i.v. infusion once every 21 days was initiated with the goal of assessing its efficacy and safety in patients (pts) with advanced acute myeloid (AML, ≥60 years old) or lymphoid (ALL, ≥18 years old) leukemia. AML pts were randomized between dinaciclib and gemtuzumab ozogamicin (GO) with cross-over to dinaciclib if no response to GO, while ALL pts only received dinaciclib. Intra-patient dose escalation of dinaciclib to 70 mg/m2 in cycle 2 was allowed. Twenty-six pts were treated on study (20 AML, 6 ALL). Data on 14 AML (2 cross-over from GO) and 6 ALL pts treated with dinaciclib are presented. Their median age was 70 (range 38–76) years and 70% were male. Sixteen pts were refractory and 4 pts had relapsed after a median of one (range 1–4) chemotherapy regimens. Four AML pts had complex karyotypes (≥3 abnormalities), 2 monosomy 7, 2 trisomy 8, 1 der (1:7)(q10;p10), 1 trisomy 21, 1 deletion 9q, and 3 had normal karyotype. Two ALL pts had t(9;22). Response: Anti-leukemia activity was observed in 60% of pts. Ten of 13 pts with circulating blasts (7/7 AML and 3/6 ALL) had >50% and 6 pts (4 AML, 2 ALL) >80% decrease in the absolute blast count (ABC) within 24 hours of the first dinaciclib dose. An additional pt had a 29% decrease in ABC. The median pre-treatment ABC was 1085 (range 220–9975) and the median ABC nadir was 169 (range 0–1350). The median duration of blast nadir was 6 days (range 2–23). A representative graph from an AML patient (below) shows a rapid decrease of circulating blasts and WBC after treatment, followed by a gradual recovery. Two patients had >50% reduction of marrow blasts (35% on d1 to 17% on d 42 in an AML pt; 81% on d1 to 27% on d 21 in an ALL pt). However, no objective responses by International Working Group criteria were observed. The median number of treatment cycles was 1 (range 1–5), with 10 pts receiving more than one cycle of treatment. Eight pts were treated with dinaciclib 70 mg/m2 starting in cycle 2. Toxicity: Treatment related AE's occurring in >30% of pts included diarrhea, nausea, vomiting, anemia, elevated AST, fatigue, leukopenia, hypocalcemia, and hypotension. The most common CTCAE v3 treatment-related grade 3 and 4 toxicities, occurring in 3 or more pts, were anemia, leukopenia, febrile neutropenia, thrombocytopenia, fatigue, increased AST, and tumor lysis syndrome (TLS). Laboratory evidence of tumor lysis in cycle 1, using the Cairo-Bishop criteria, was seen in 6 pts in addition to 3 pts with clinical TLS (JCO 2008;26:2767). Hyperacute TLS requiring hemodialysis occurred in one pt with AML, who died of acute renal failure. Subsequently, all pts were aggressively managed to prevent and treat TLS (hospitalization, hydration, allopurinol, rasburicase, oral phosphate binder administration, and early management of hyperkalemia). An additional 9 pts died on study, 8 pts from leukemia progression and 1 pt from intracranial bleed due to disease-related thrombocytopenia. Pharmacodynamics: Pre-treatment, 4 and 24 hrs post end-of-infusion samples of circulating leukemic blasts were obtained from 1 AML and 3 ALL pts. By Western blot, post-treatment decrease in Mcl-1 and increase in PARP cleavage were seen in all 4 pts at 4 hrs post-treatment, confirming that in vivo inhibition of CDKs was achieved, but recovery of Mcl-1 at 24 hrs was observed in all 4 pts, suggesting that inhibition was lost at 24 hrs. Decline in p-Rb was observed in 1 pt, while 2 pts had almost undetectable p-Rb levels at baseline. Conclusion: Dinaciclib showed anti-leukemia activity in this heavily pre-treated patient population. TLS was a notable toxicity, but was manageable in most pts with aggressive prophylaxis, monitoring and treatment. Early blast recovery and short duration of nadir observed on this study, combined with PK data showing a short t1/2 (1.5-3.3 hours) for dinaciclib and PD data demonstrating rapid reexpression of Mcl-1, support either use of longer infusion schedules (currently explored in solid tumors) or more frequent drug administration. Further exploration of dinaciclib dose and schedules in AML and ALL is planned. Disclosures: Gojo: Merck & Co.: Research Funding. Off Label Use: SCH 727965 (dinaciclib) is an investigational drug. Padmanabhan:Schering-Plough: Consultancy; Merck & Co.: Research Funding. Small:Merck & Co.: Employment, Equity Ownership. Zhang:Merck & Co.: Employment. Sadowska:Merck & Co.: Research Funding. Bannerji:Merck & Co.: Employment, Equity Ownership.

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A Phase 1 Study of Prasugrel in Subjects with Sickle Cell Disease: Effects on In Vivo Markers of Platelet Activation and of Coagulation

Blood ◽

10.1182/blood.v118.21.1049.1049 ◽

2011 ◽

Vol 118 (21) ◽

pp. 1049-1049

Author(s):

Joseph A. Jakubowski ◽

Chunmei Zhou ◽

David S. Small ◽

Kenneth J. Winters ◽

D. Richard Lachno ◽

...

Keyword(s):

Sickle Cell Disease ◽

Platelet Activation ◽

Sickle Cell ◽

Research Funding ◽

Blood Platelet ◽

Cell Disease ◽

Employment Equity ◽

Equity Ownership ◽

Adp Receptor

Abstract Abstract 1049 Introduction: Evidence suggests that platelets are activated in sickle cell disease (SCD) and this appears to increase further during painful crises caused by vascular occlusions from sickled red blood cells. Antiplatelet therapy may be useful in reducing the frequency and severity of acute pain episodes and reducing the risk of thrombotic complications. Prasugrel, an ADP receptor antagonist, irreversibly inhibits the P2Y12 ADP receptor, blocking ADP-stimulated platelet activation and aggregation and reducing downstream procoagulant activities. Here we present the first evaluation of prasugrel's effects on markers of in vivo platelet activation and of coagulation in subjects with SCD. Methods: Twenty-six adult subjects were enrolled and 25 completed the study: 12 with SCD and 13 well-matched healthy controls. Subjects were examined before and after 12±2 days of treatment with oral prasugrel (5.0 mg/day for subjects weighing <60 kg and 7.5 mg/day for subjects weighing ≥60 kg). Markers of platelet activation and coagulation included whole-blood platelet-monocyte and -neutrophil aggregates, and whole blood platelet-associated P-selectin and platelet CD40L, all measured by flow cytometry and presented as percent (%) of marker positive cells. Plasma soluble (s) P-selectin, CD40L, and plasma prothrombin fragment 1.2 (F1.2) were evaluated by ELISA. Results: Results from the biomarkers are presented in the table. Prior to prasugrel administration (baseline), subjects with SCD had significantly higher levels of the following biomarkers compared to healthy subjects: Platelet-monocyte aggregates, platelet-neutrophil aggregates, platelet CD40L, and plasma F1.2. In addition, subjects with SCD had numerically higher values of sCD40L, as well as platelet-associated and sP-selectin. Prasugrel treatment resulted in numerical decreases in levels of all biomarkers (with the exception of platelet-associated CD40L for control subjects), most notably in SCD subjects with elevated baseline levels. Prasugrel was safe and well tolerated with no serious adverse events observed during the study. No subject discontinued the study due to an adverse event (AE) and the majority of AEs were mild. No subjects with SCD reported any bleeding-related AEs. Conclusion: In this study, compared to healthy controls, baseline elevation of several platelet-activation and coagulation markers among adult subjects with SCD is consistent with that seen in previous studies of both children and adults with SCD. The decrease in platelet activation biomarkers following 12 days of prasugrel treatment in subjects with SCD suggests prasugrel interrupts SCD-related platelet activation in vivo and raises the possibility that prasugrel may modulate the frequency and/or severity of painful crises associated with SCD. These data support additional studies of the safety and efficacy of prasugrel in the treatment of vascular complications associated with SCD. Disclosures: Jakubowski: Eli Lilly and Company: Employment, Equity Ownership. Off Label Use: This abstract discusses prasugrel treatment in patients with sickle cell disease. Please see USPI for most up-to-date information. Zhou:Eli Lilly and Company: Employment, Equity Ownership. Small:Eli Lilly and Company: Employment, Equity Ownership. Winters:Eli Lilly and Company: Employment, Equity Ownership. Lachno:Eli Lilly and Company: Employment, Equity Ownership. Frelinger:Takeda: Research Funding; Daiichi Sankyo Company, Ltd. and Eli Lilly and Company: Consultancy, Research Funding; GLSynthesis: Research Funding. Howard:Daiichi Sankyo Company, Ltd. and Eli Lilly and Company: Research Funding. Payne:Eli Lilly and Compnay: Employment, Equity Ownership.

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Stroma-Free Ex Vivo Expanded, CD34+ Cord Blood-Derived NK Cells Retain Lytic Activity After Long-Term Engraftment in NSGS Mice

Blood ◽

10.1182/blood.v120.21.580.580 ◽

2012 ◽

Vol 120 (21) ◽

pp. 580-580

Author(s):

Mark Wunderlich ◽

Mahesh Shrestha ◽

Lin Kang ◽

Eric Law ◽

Vladimir Jankovic ◽

...

Keyword(s):

Nk Cells ◽

Research Funding ◽

Nk Cell ◽

Ex Vivo ◽

Employment Equity ◽

Cell Product ◽

Equity Ownership ◽

Cellular Therapeutics

Abstract Abstract 580 Generating a large number of pure, functional immune cells that can be used in human patients has been a major challenge for NK cell-based immunotherapy. We have successfully established a cultivation method to generate human NK cells from CD34+ cells isolated from donor-matched cord blood and human placental derived stem cells, which were obtained from full-term human placenta. This cultivation method is feeder-free, based on progenitor expansion followed by NK differentiation supported by cytokines including thrombopoietin, stem cell factor, Flt3 ligand, IL-7, IL-15 and IL-2. A graded progression from CD34+ hematopoietic progenitor cells (HSC) to committed NK progenitor cells ultimately results in ∼90% CD3-CD56+ phenotype and is associated with an average 10,000-fold expansion achieved over 35 days. The resulting cells are CD16- and express low level of KIRs, indicating an immature NK cell phenotype, but show active in vitro cytotoxicity against a broad range of tumor cell line targets. The in vivo persistence, maturation and functional activity of HSC-derived NK cells was assessed in NSG mice engineered to express the human cytokines SCF, GM-CSF and IL-3 (NSGS mice). Human IL-2 or IL-15 was injected intraperitoneally three times per week to test the effect of cytokine supplementation on the in vivo transferred NK cells. The presence and detailed immunophenotype of NK cells was assessed in peripheral blood (PB), bone marrow (BM), spleen and liver samples at 7-day intervals up to 28 days post-transfer. Without cytokine supplementation, very few NK cells were detectable at any time-point. Administration of IL-2 resulted in a detectable but modest enhancement of human NK cell persistence. The effect of IL-15 supplementation was significantly greater, leading to the robust persistence of transferred NK cells in circulation, and likely specific homing and expansion in the liver of recipient mice. The discrete response to IL-15 versus IL-2, as well as the preferential accumulation in the liver have not been previously described following adoptive transfer of mature NK cells, and may be unique for the HSC-derived immature NK cell product. Following the in vivo transfer, a significant fraction of human CD56+ cells expressed CD16 and KIRs indicating full physiologic NK differentiation, which appears to be a unique potential of HSC-derived cells. Consistent with this, human CD56+ cells isolated ex vivo efficiently killed K562 targets in in vitro cytotoxicity assays. In contrast to PB, spleen and liver, BM contained a substantial portion of human cells that were CD56/CD16 double negative (DN) but positive for CD244 and CD117, indicating a residual progenitor function in the CD56- fraction of the CD34+ derived cell product. The BM engrafting population was higher in NK cultures at earlier stages of expansion, but was preserved in the day 35- cultured product. The frequency of these cells in the BM increased over time, and showed continued cycling based on in vivo BrdU labeling 28 days post-transfer, suggesting a significant progenitor potential in vivo. Interestingly, DN cells isolated from BM could be efficiently differentiated ex vivo to mature CD56+CD16+ NK cells with in vitro cytotoxic activity against K562. We speculate that under the optimal in vivo conditions these BM engrafting cells may provide a progenitor population to produce a mature NK cell pool in humans, and therefore could contribute to the therapeutic potential of the HSC-derived NK cell product. The in vivo activity of HSC-derived NK cells was further explored using a genetically engineered human AML xenograft model of minimal residual disease (MRD) and initial data indicates significant suppression of AML relapse in animals receiving NK cells following chemotherapy. Collectively, our data demonstrate the utility of humanized mice and in vivo xenograft models in characterizing the biodistribution, persistence, differentiation and functional assessment of human HSC-derived cell therapy products, and characterize the potential of HSC-derived NK cells to be developed as an effective off-the-shelf product for use in adoptive cell therapy approaches in AML. Disclosures: Wunderlich: Celgene Cellular Therapeutics: Research Funding. Shrestha:C: Research Funding. Kang:Celgene Cellular Therapeutics: Employment, Equity Ownership, Patents & Royalties. Law:Celgene Cellular Therapeutics: Employment, Equity Ownership, Patents & Royalties. Jankovic:Celgene Cellular Therapeutics: Employment, Equity Ownership, Patents & Royalties. Zhang:Celgene Cellular Therapeutics: Employment, Equity Ownership, Patents & Royalties. Herzberg:Celgene Cellular Therapeutics: Employment, Equity Ownership, Patents & Royalties. Abbot:Celgene Cellular Therapeutics: Employment, Equity Ownership, Patents & Royalties. Hariri:Celgene Cellular Therapeutics: Employment, Equity Ownership, Patents & Royalties. Mulloy:Celgene Cellular Therapeutics: Research Funding.

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Absence Of Mutation In Cereblon (CRBN) and DNA Damage Binding Protein 1 (DDB1) Genes In Myeloma Cells and Patients and Its Clinical Significance

Blood ◽

10.1182/blood.v122.21.3139.3139 ◽

2013 ◽

Vol 122 (21) ◽

pp. 3139-3139

Author(s):

Anjan Thakurta ◽

Anita K Gandhi ◽

Michelle Waldman ◽

Chad C. Bjorklund ◽

Suzanne Lentzsch ◽

...

Keyword(s):

Board Of Directors ◽

Cell Lines ◽

Research Funding ◽

Heterozygous Mutation ◽

Employment Equity ◽

Advisory Committees ◽

Single Nucleotide ◽

Truncating Mutation ◽

Equity Ownership

Abstract Background CRBN, a target of thalidomide and IMiDs® immunomodulatory agents lenalidomide (LEN) and pomalidomide (POM), is a component of the E3 ubiquitin cullin 4 ring ligase (CRL4) complex that also includes DDB1, Roc1, and Cul4. Two CRBN mutations have been reported in multiple myeloma (MM) patients: truncating mutation (Q99) and point mutation (R283K). One copy of the CRBN gene was shown to be deleted in the MM1S and MM1S.R cell lines. No DDB1 mutation has been described previously. Results We investigated the incidence of CRBN and DDB1 mutations by next-generation sequencing in 20 MM cell lines and MM subjects. Of 90 MM patients, 24 were newly diagnosed and 66 were relapsed and refractory of which 36 patients were LEN resistant. Out of the cell lines tested, 1 heterozygous CRBN mutation (D249Y) was found in the LEN-resistant ANBL6R cells, which is located in the putative DDB1 binding domain, and 2 single silent mutations were identified in the KMS-12-BM (rs17027638) and OPM-2 cells. One DDB1 heterozygous mutation (E303D) was identified in ANBL6 cells. In the cohort of patients assessed, no CRBN mutation was detected; however, 5 single nucleotide variations (SNV) were identified. Three of the 5 SNVs were at position 735 (Y245Y) and 1 each at position 219 (H73H) and 939 (C313C), respectively. The first 2 SNVs (rs17027638 and rs1045309) are described but not the last. We found a single SNV (P51P; rs2230356) in DDB1 gene the patient samples. Conclusion Mutations within the coding sequences of CRBN and DDB1 are rare in MM patients and cell lines. Most intrinsically LEN-resistant cells and cell lines made resistant to LEN or POM do not have CRBN or DDB1 mutations, suggesting the potential role of other sources, such as genetic or epigenetic pathways in developing resistance to IMiD drug–based therapy. Disclosures: Thakurta: Celgene: Employment, Equity Ownership. Gandhi:Celgene: Employment, Equity Ownership. Waldman:Celgene: Employment, Equity Ownership. Bjorklund:Celgene: Employment, Equity Ownership. Lentzsch:Celgene: Research Funding. Schey:Celgene: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau; NAPP: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau; BMS: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau. 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: 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: 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. Madan:Covance Genomics Lab: Employment. Ning:Celgene: Employment, Equity Ownership. Mendy:Celgene: Employment, Equity Ownership. Lopez-Girona:Celgene: Employment, Equity Ownership. Schafer:Celgene: Employment, Equity Ownership. Avet-Loiseau:Celgene: Research Funding. Chopra:Celgene: Employment, Equity Ownership.

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