The Biologic Relevance of PIM Kinases in the Context of Multiple Myeloma and Their Potential As Therapeutic Targets in Combination Drug Therapy

Abstract The proto-oncogene proviral integration sites for moloney murine leukemia virus (PIM) are serine/threonine kinases currently under investigation as therapeutic targets in hematologic cancers, where they have important functional roles as mediators of apoptosis, cell migration and homing. Thus far in Multiple Myeloma (MM), the PIM Kinases have been shown to mediate cap-dependent and cap-independent translation through the PI3K/AKT pathway and the activation of mTOR signaling (Lu J et al. 2013). In the context of the bone marrow microenvironment, PIM kinase expression in MM cells is known to be elevated in the presence of bone marrow stromal cells, and is mediated by the IL-6/STAT3 pathway, as well as the TNFα/NFΚB pathway (activated by Osteoclast secretion) (Hiasa M et al. 2014). Here, we have further studied the role of PIM kinases in MM. We observed elevated expression of PIM 1, 2 and 3 in patient derived myeloma cells (CD138+) as opposed to the stromal compartment (CD138-), confirming that PIM expression is predominantly hematologic lineage-specific. Inhibition of all three kinases by a pan PIM inhibitor results in reduced cell viability in tested human-derived MM cell lines, reinforcing the importance of the kinases as targets in drug therapy, as shown previously. Because the expression of Pim2 is consistently higher in primary tumor cells as well as in human MM lines, compared to Pim1 and Pim3, we sought to identify their distinct biologic significance. Single knock down (KD) of each kinase resulted in varying effects on cell viability, suggesting, together with the PIM expression profile, that the three kinases play different roles in the biology of MM. As the Pim2 KD resulted in the most profound decrease in cell viability, we focused our efforts to dissect the mechanistic importance of Pim2. Since Pim1 and Pim2 regulate the DNA damage response (DDR) via checkpoint kinase 1 (Chk1) in other hematologic malignancies, we investigated the effect of Pim2 KD on major signaling factors involved in the DDR. Transient KD resulted in phosphorylation of DDR pathway markers including ATR, CHK1/2, P21 and H2AX, and mimicked the effects of Doxorubicin treatment (a known DNA Damage causing agent). Furthermore, Doxorubicin treatment downregulated Pim2 expression, suggesting that Pim2 functions as an upstream regulator of the DDR pathway in MM. Pim2 appears to be the most relevant target in MM; however, because of a lack of a specific PIM2 inhibitor we used the pan-PIM inhibitor as a tool compound. Although the pan PIM kinase inhibitor showed single agent activity, combination approaches were more efficacious. Combining the pan-PIM inhibitor with bortezomib shows a significant synergistic effect on cell viability in multiple MM cell lines (MM1S, U266, KMS-12BM). Based on our KD experiments Pim2 predominantly mediates cell viability, suggesting that specifically targeting Pim2 in combination with Bortezomib will have a more direct effect on MM cell survival. To confirm the role of Pim2, ongoing experiments aim to focus on the effects of ectopically expressing Pim2 in the context of myeloma. We propose that Pim2 overexpression will not only serve anti-apoptotic purposes, but will further protect against DNA Damage in human MM cell lines. Disclosures Chauhan: Stemline Therapeutics: Consultancy. Huszar:Astra Zeneca: Employment. Raje:AstraZeneca: Research Funding; Onyx: Consultancy; BMS: Consultancy; Acetylon: Research Funding; Millenium: Consultancy; Amgen: Consultancy; Novartis: Consultancy; Takeda: Consultancy; Eli Lilly: Research Funding; Celgene Corporation: Consultancy.

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Long Non-Coding RNAs Annotation and Their Involvement in Multiple Myeloma

Blood ◽

10.1182/blood.v128.22.4420.4420 ◽

2016 ◽

Vol 128 (22) ◽

pp. 4420-4420 ◽

Cited By ~ 1

Author(s):

Arantxa Carrasco ◽

Teresa Ezponda ◽

Cem Meydan ◽

Marta Kulis ◽

Raquel Ordoñez ◽

...

Keyword(s):

Dna Methylation ◽

Multiple Myeloma ◽

Bone Marrow ◽

B Cell ◽

Cell Lines ◽

Promoter Region ◽

Research Funding ◽

Epigenetic Mechanisms ◽

Non Coding Rnas

Abstract Increasing amount of evidence indicates that the deregulation of non-coding elements is a common feature of cancer and therefore, its investigation may uncover new molecular oncogenic mechanisms. In multiple myeloma (MM), the altered expression of a small number of long non-coding RNAs (lncRNAs) has been associated with progression and decreased survival, suggesting that these elements may play a more important role in this disease than previously expected. Nevertheless, an extensive high-throughput analysis that characterizes the deregulation of lncRNAs in MM has not yet been performed. To characterize the transcriptome, including all genomic types of lncRNAs, of MM we performed a paired end strand-specific RNA sequencing (ssRNA-seq) in 38 purified plasma cell (PC) samples from MM patients, as well as PC samples from tonsils (TPCs, n=5) and bone marrow (BMPCs, n=3) of healthy donors as controls. Principal component analysis (PCA) demonstrated that normal PC samples from tonsil and bone marrow cluster separately, suggesting that in spite of being the same cell type, their coding and non coding transcriptomes are very different. Therefore, we selected BMPCs as the normal counterparts for comparison with BM of MM samples. PCA analysis also demonstrated that the well known heterogeneity of MM patients rely not only on the coding transcriptome but also on the lncRNA expression profile. Comparison of MM to BMPCs samples showed 70 previously annotated lncRNAs that were deregulated in MM patients, with 3 lncRNAs showing higher and 67 lower expression than normal BMPCs. Moreover, we identified 40.552 novel MM-specific lncRNAs that were present in at least 3 of the 38 patients, highlighting the magnitude of the deregulation of these non coding elements in MM. To determine the functional role of altered lncRNAs in the biology of MM plasma cells we focused on the study of LINC-MSL1 (Myeloma-Specific LncRNA 1). Analysis of the expression of this lncRNA at different stages of B-cell differentiation (Naïve, Germinal Center, Memory and PC) indicated that it is not expressed at any stage, except for a modest expression in BMPCs. Interestingly, its overexpression was detected in 40% of MM specimens when compared to normal BMPCs which was validated by qPCR in an independent cohort of MM patients. To determine whether the expression of this lncRNA is regulated by epigenetic mechanisms, we studied the DNA methylation state of this gene. DNA methylation analysis in MM demonstrated that the CpGs located upstream of LINC-MSL1 were differentially methylated in comparison with normal counterpart BMPC. These CpGs showed 70% DNA methylation in control samples, about 40% in MGUS, whereas the average of MM was about 20%, showing a remarkable hypomethylation. We validated these results by pyrosequencing, which showed a significantly lower DNA methylation at the promoter region in comparison with B cell populations from tonsil, normal BMPCs and cell lines that do not overexpress LINC-MSL1. We also have observed a gain of active chromatin states analyzed by ChiP-seq in the promoter region of LINC-MSL1 in MM patient samples. These data suggest that epigenetic mechanisms, namely the progressive hypomethylation and the gain of active histone modifications, are the cause of the overexpression of LINC-MSL1 in MM. To analyze the role of the overexpression of LINC-MSL1 in MM, we engineered two MM cell lines that show high levels of LINC-MSL1, MM.1S and MM.1R, to express shRNAs against this lncRNA. Knockdown of LINC-MSL1 by two different shRNAs resulted in a reduced proliferation of the cell lines over time. This effect was not associated with a cell cycle arrest but with a marked increased in the percentage of Annexin V-positive apoptotic cells, indicating that the overexpression of LINC-MSL1 is necessary for the survival of MM cells. All together, these data demonstrate that the alteration of lncRNAs is an important an unexplored feature that contributes to MM pathogenesis. The overexpression of LINC-MSL1 is essential for MM survival and is very specific of MM BMPCs, suggesting it could be a relevant therapeutic target. Disclosures Paiva: Celgene: Honoraria, Research Funding; Janssen: Honoraria; Takeda: Honoraria, Research Funding; Sanofi: Consultancy, Research Funding; EngMab: Research Funding; Amgen: Honoraria; Binding Site: Research Funding. Melnick:Janssen: Research Funding.

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Potential Therapeutic Role of the Selective Adhesion Molecule (SAM) Inhibitor Natalizumab in Multiple Myeloma.

Blood ◽

10.1182/blood.v114.22.1850.1850 ◽

2009 ◽

Vol 114 (22) ◽

pp. 1850-1850 ◽

Cited By ~ 1

Author(s):

Klaus Podar ◽

Alexander Zimmerhackl ◽

Ursula Hainz ◽

Mariateresa Fulciniti ◽

Sonia Vallet ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

Cell Migration ◽

Cell Adhesion ◽

Cell Surface ◽

Adhesion Molecule ◽

Research Funding ◽

Therapeutic Role ◽

Potential Therapeutic Role

Abstract Abstract 1850 Poster Board I-876 Multiple Myeloma (MM) is characterized by the clonal proliferation of malignant plasma cells in the bone marrow. Despite current therapeutic approach and prolongation of the median survival, new therapies are urgently needed. Integrins are cell surface receptors which mediate both cell-cell adhesion and cell-extracellular matrix (ECM) protein adhesion. beta1-integrins, including very-late antigen-4 (VLA-4;á4β1), are typically expressed on MM cells. In MM, VLA-4-mediated binding to ECMS and bone marrow stromal cells (BMSCs) confers protection against drug-induced apoptosis and triggers transcription and secretion of IL-6, the major MM growth and survival factor. In addition to up-regulation of cell surface-clustering, integrin activity can also be triggered by multiple agonists through ‘inside-out’ signaling, independent of changes in integrin expression levels. Importantly, VEGF-induced migration of MM cells on fibronectin is also associated with β1-integrin- and PI3-kinase- dependent PKC activation. Targeting VLA-4 is therefore of potential high therapeutic interest in MM. Indeed, an antibody against murine á4 induces inhibition of MM growth in a murine model. Natalizumab is a recombinant humanized IgG4 monoclonal antibody, which belongs to a new class of molecules known as selective adhesion molecule (SAM) inhibitors and binds to á4-integrin. Clinically, Natalizumab has demonstrated activity in patients with multiple sclerosis and Crohn's disease. Here we tested the potential therapeutic role of Natalizumab on MM cell survival, and migration in the BM microenvironment. VLA-4 is expressed by all MM cell lines investigated (NCIH929, RPMI8226, INA-6, MM.1S, and OPM2). Functionally, Natalizumab but not a control antibody, triggered dose-dependent inhibition of MM cell adhesion to fibronectin, BMSCs, and endothelial cells (ECs). Importantly, inhibition of adhesion to fibronectin, BMSCs, or ECs was observed in MM cells pretreated with Natalizumab. Moreover, inhibition of MM cell adhesion to fibronectin, BMSCs, or ECs was also observed when Natalizumab was added to already adherent MM cells. Taken together, Natalizumab decreases adhesion of non-adherent MM cells as well as binding of already adherent MM cells to non-cellular and cellular components of the microenvironment. Given the protective role of the microenvironment on MM cell survival, we next sought to evaluate the chemosensitizing activity of Natalizumab. Specifically, we investigated dose- and time- dependent effects of Natalizumab, alone and when combined with conventional and novel therapies, on MM cells. Our results show that Natalizumab alone did not inhibit growth or survival of MM cells when cultured without components of the microenvironment. However, Natalizumab enhanced sensitivity of tumor cells to both bortezomib and dexamethasone in MM-BMSC and, MM-EC co-cultures. These data indicate a potential role of Natalizumab in bortezomib- and dexamethasone-containing treatment regimens including MPV. Moreover, Natalizumab decreases IL-6 and VEGF secretion triggered in MM-BMSC co-cultures. Consequently, angiogenesis triggered by supernatants of Natalizumab- treated MM-BMSC co-cultures was inhibited. Moreover, Natalizumab blocked MM cell migration on fibronectin triggered by both VEGF and IGF-1. Finally, our previous results implicate an PKC signaling in MM cell migration on fibronectin, and our current results show that Natalizumab inhibits phosphorylation of á4 integrins and PKC induced by co-stimulation with VEGF/ fibronectin, IGF-1/ fibronectin, and patient serum. Taken together, our data indicate a potential therapeutic role of Natalizumab in MM. Ongoing studies evaluating the effect of Natalizumab in a SCID-hu murine model of MM will also be reported. Disclosures: Podar: Biogen Idec: Research Funding. Off Label Use: natalizumab, integrin inhibitor. Zimmerhackl:Biogen Idec: Research Funding. Olsen:Biogen Idec: Employment.

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Genome Wide DNA Methylation Profiling In Patients with Multiple Myeloma.

Blood ◽

10.1182/blood.v116.21.3622.3622 ◽

2010 ◽

Vol 116 (21) ◽

pp. 3622-3622

Author(s):

Yang Liu ◽

Shenghua Duan ◽

Xavier Leleu ◽

Yong Zhang ◽

Abdel Kareem A. Azab ◽

...

Keyword(s):

Dna Methylation ◽

Bone Marrow ◽

Cell Lines ◽

Promoter Region ◽

Genomic Dna ◽

Research Funding ◽

Plasma Cells ◽

Genome Wide

Abstract Abstract 3622 Introduction: Epigenetic factors such as DNA methylation have been shown to play a crucial role in the pathogenesis and progression of multiple myeloma (MM), yet studies of DNA methylation in MM are still limited. Therefore, in order to better understand the role of DNA methylation and identify specific genes that may be affected by differential methylation in MM patients, we conducted genome-wide DNA methylation profiling in cd138+ plasma cells purified from bone marrow of the patients with MM and normal donors. Methods: Genomic DNA of CD138+ Plasma cell selected from both MM patients and normal primary bone marrow was extracted using QIAGEN genome isolation kit. Following extraction, methylated DNA was isolated by Chip and hybridized to Affymetrix Human 2.0 tiling arrays. Chip assay and array hybridization was performed by Genepathway Inc. CEL files were processed and normalized using the MAT program, and methylation peaks were called from the resulting MAT scores using a custom segmentation method. Peak annotation and characterization of different genomic regions was done with custom tools and using genome annotation files from the UCSC genome database. All peaks were visualized by IGB online software. Medip-PCR was done in human MM cell lines to validate the methylation status. Methylated gene expression was determined by both Semi-quantitative PCR and real-time PCR. 5′aza was used for demethylation in human MM cell lines. Methylated gene expression with or without 5′aza treatment was determined by both Semi-quantitative PCR and real-time PCR. Results: Genomic DNA from CD138+ plasma cells from bone marrow of MM patients showed a significant increase in methylation levels compared to normal controls. We demonstrated that the hypermethylated sites were distributed across the genome in the following proportions: 3.2% in the promoter region; 45.6% in the intragenic region; 5.4 % in the 3′ end region; and 46.8 % in the intergenic region. Furthermore, around 9 % promoter CpG islands (CGIs); 11% intragenic CGIs; 15 % CGIs in 3′end region; and 14.3 % intergenic CGIs of patients genomic DNA were methylated. Moreover 2.1% promoter CGIs; 2.3 % intragenic CGIs; 2.5% CGIs in 3′end region; and 4.7% intergenic CGIs were methylated for the normal control. Medip-PCR showed that the identified methylation pattern in MM patients showed similar results in MM cell lines. Expectedly, we also observed that suppressor of cytokine signaling 1 (SOCS1) was hypermethylated at the promoter region (MAT score=19.986) as has been reported in human cell lines. Importantly, another member of SOCS family SOCS3 showed much stronger signal in the promoter region with CpG island (MAT score=31.707) in MM patients compared to normal control. Notably, the expression of two members of TNFR superfamily TNFRSF18 and TNFRSF4 which play an important role in development and programmed cell death of lymphocyte significantly have increased 283 and 141-fold after treatment with 5′aza in MM cell lines. Conclusion: These findings enhance our understanding of the role of DNA methylation in MM, as one of the epigenetic changes that may contribute to the pathogenesis of this disease. The identification and functional characterization of novel key molecules affected by DNA methylation will provide deeper insight into the molecular basis of MM disease. Disclosures: Leleu: Celgene: Consultancy, Research Funding; Janssen Cilag: Consultancy, Research Funding; Leo Pharma: Consultancy; Amgen: Consultancy; Chugai: Research Funding; Roche: Consultancy, Research Funding; Novartis: Consultancy, Research Funding. Anderson:Millennium Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau.

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Frequent Dysregulation of Fc Gamma Receptor IIb (Fc γRIIb) and Immunoreceptor Tyrosine-Based Inhibitory Motif (ITIM) Signaling Occurs in Multiple Myeloma (MM) Patients

Blood ◽

10.1182/blood.v118.21.2917.2917 ◽

2011 ◽

Vol 118 (21) ◽

pp. 2917-2917

Author(s):

Jennifer Li ◽

Andrew Leu ◽

Mingjie Li ◽

Ethan D Hobel ◽

Kevin Delijani ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

B Cells ◽

Cell Lines ◽

Research Funding ◽

Plasma Cells ◽

Critical Role ◽

Rt Pcr ◽

Binding Ability ◽

Downstream Signaling

Abstract Abstract 2917 The inhibitory Fc receptor, Fc γRIIb, is expressed on plasma cells, controls their persistence in the bone marrow (BM) and their ability to produce serum Ig. Activation of Fc γRIIb leads to the phosphorylation of ITIM and recruitment of SH2-containing inositol 5'-phosphatase (SHIP) in plasma cells. Immunoreceptor tyrosine-based activation motif (ITAM) and ITIM provide the basis for two opposing signaling modules that duel for control of plasma cell activation. Fc γRIIb-mediated SHIP phosphorylation activates downstream ITAM or ITIM signaling. To determine whether multiple myeloma (MM) cells express Fc γRIIb, we performed immunohistochemical staining on bone marrow mononuclear cells from MM patients and controls. We found that not only CD20+ B cells expressed Fc γRIIb but more importantly CD138+ cells from MM patients also showed expression of this receptor. Next, we examined whether Fc γRIIb was present and expressed in CD138+ primary MM cells purified from fresh MM BM and the MM cell lines MM1s, RPMI8226, and U266 using PCR and RT-PCR on DNA and mRNA, respectively. We focused on the transmembrane domain of the Fc γRIIb gene with four primers from different parts of this domain since this portion plays a critical role in this receptor's function. The MM cell lines expressed different amounts of Fc γRIIb. Notably, we found that 17% (5/30) of MM patients showed absence of Fc γRIIb both using RT-PCR for mRNA and PCR for DNA. Moreover, use of these same primers on nonmalignant PBMCs from the MM patients also showed absence of this gene in the same five patients. As a result of these findings, we are currently sequencing Fc γRIIb in MM patients to determine if additional patients show mutational changes that affect the function of this receptor. We also further determined SHIP-1 phosphorylation using Western blot analysis since this protein mediates downstream signaling of Fc γRIIb. Following stimulation with Fc complexes, phosphorylation of SHIP-1 was markedly reduced in MM tumor cells compared to normal CD20+ B cells. Interestingly, the patients with missing Fc γRIIb expressed higher levels of SHIP-1 gene expression compared to patients with normal Fc γRIIb expression. We investigated the IgG-binding ability of MM patients (n=33) and normal donors (n=33) to Fc γRIIb. Each serum sample was incubated with cells from MHC1, a cell line that specifically expresses Fc γRIIb but not Fc γRI and Fc γRIIa. The results showed MM patients' serum IgG have much lower Fc γRIIb-binding ability than normal human IgG (P<0.05) by using both flow cytometric and immunofluorescence assays. Our findings suggest that the monoclonal protein produced by MM patients has a very low Fc γRIIb-binding ability and is incapable of signaling through the inhibitory ITIM pathway. Germline loss of Fc γRIIb in MM patients with variation in its expression level and its downstream signaling molecule SHIP and its phosphorylation as well as the inability of MM IgG to bind cells containing this receptor is a potential new mechanism that contributes to the uncontrolled growth of MM. Disclosures: Berenson: Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau; Millennium Pharmaceuticals, Inc.: Consultancy, Honoraria, Research Funding, Speakers Bureau; Onyx Pharmaceuticals: Consultancy, Honoraria, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau; Medtronic: Consultancy, Honoraria, Research Funding, Speakers Bureau; Merck: Research Funding; Genentech: Research Funding.

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PIM Kinase Inhibition Decreases the Proangiogenic Properties of Multiple Myeloma Cells and Affects the Metabolic State of the Vascular Endothelium

Blood ◽

10.1182/blood-2020-134979 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 16-17

Author(s):

Filip Garbicz ◽

Anna Szumera-Ciećkiewicz ◽

Joanna Barankiewicz ◽

Dorota Komar ◽

Michał Pawlak ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

Endothelial Cells ◽

Cell Death ◽

Tumor Cell ◽

Cell Lines ◽

Fold Increase ◽

Pim Kinases ◽

Rpmi 8226

The development and progression of multiple myeloma (MM) depend on the formation and perpetual evolution of an immunosuppressive and hypervascular bone marrow microenvironment. MM undergoes an angiogenic switch during its early progression stages and initiates the secretion of proangiogenic proteins, such as VEGFA and Galectin-1. Following their engagement with the VEGF receptor 2 on the surface of the endothelium, quiescent endothelial cells (ECs) rapidly switch to an activated state, thus gaining the ability to create sprouts, migrate and proliferate. However, chronic angiogenic stimulation results in the formation of a dense and leaky network of pathological vessels, which in the case of MM also serves as a major source of prosurvival paracrine signals. Since PIM kinases are known modulators of cytokine signaling, owing to their ability to activate NFκB, JAK/STAT and mTOR pathways, we analyzed the expression pattern of PIM1, PIM2 and PIM3 in multiple myeloma bone marrow samples using immunohistochemistry. We found that both MM cells as well as myeloma-associated ECs exhibit a significantly higher PIM3 expression than their normal bone marrow counterparts. Since the role of PIM kinases in the vascular compartment of the tumor microenvironment is currently unknown, we decided to explore the proangiogenic functions of PIM kinases using in vitro MM and EC model cell lines. 3 MM cell lines (RPMI 8226, MM1.s, U266), immortalized bone marrow ECs (HBMEC-60) and human umbilical vein ECs (HUVECs) were used for the experiments. Primary MM cells were obtained from MACS-separated bone marrow aspirates. Chemical blockade of PIM kinase activity was achieved using the pan-PIM inhibitor SEL24/MEN1703. The compound decreased the viability of MM cell lines with IC50 in the submicromolar range, induced G2 cell cycle arrest and apoptosis. Moreover, SEL24/MEN1703 induced apoptosis in primary MM cells, even when cocultured with the CD138- bone marrow fraction. PIM inhibitor treatment inhibited the phosphorylation of mTOR substrates S6 and 4EBP1, STAT3/5, as well as RelA/p65. Consequently, we observed markedly decreased VEGFA and Gal-1 levels in SEL24/MEN1703-treated MM cells. When cultured together, separated by a permeable transwell membrane, both RPMI 8226 cells, as well as ECs, exhibited a 2-fold increase in proliferation rate. This effect was completely blocked by a 2-day treatment with a PIM inhibitor. Exposure of ECs to recombinant VEGFA (10ng/ul) or MM supernatant resulted in an increase in VEGFR2 Y1175 phosphorylation level and induction of PIM3 expression. Increased MYC activity is a hallmark of VEGF-dependent endothelial activation and is necessary to support the creation of new vessels. Since the PIM3 promoter region contains putative MYC-binding sites (E-boxes), we checked if PIM3 induction depends on MYC in ECs. MYC silencing using siRNA resulted in an 88% lower PIM3 expression than the non-targeting siRNA. One of MYC's main tasks during angiogenesis is the stimulation of cellular ATP synthesis to meet the energy demands created by the dynamic remodeling of the actin cytoskeleton. Surprisingly, PIM inhibition decreased the total ATP content in ECs by 25%, thus disrupting the energetic homeostasis, as evidenced by a 9.6-fold increase in phosphorylated AMPK T172 levels. Furthermore, SEL24/MEN1703-treated ECs were depleted of higher-order actin structures necessary for efficient angiogenesis, such as actin stress fibers, membrane ruffles and lamellipodia. In consequence, PIM kinase inhibition decreased proliferation, migration and formation of new vessel-like structures in Matrigel by ECs. Collectively, our data demonstrate that PIM inhibition induces MM cell death and abolishes important tumor cell-ECs interactions. In addition, we show that PIM3 is overexpressed in MM tumor endothelial cells and PIM inhibition disrupts the activation state in in vitro cultured ECs. Hence, targeting PIM kinases may represent an efficient approach to induce tumor cell death and to block angiogenesis in MM. RNA-sequencing studies on the downstream effectors of PIM3 are currently ongoing in order to unravel the molecular mechanism behind the observed effects. Figure Disclosures Brzózka: Ryvu Therapeutics: Current Employment. Rzymski:Ryvu Therapeutics: Current Employment. Tomirotti:Menarini Ricerche: Current Employment. Lech-Marańda:Roche, Novartis, Takeda, Janssen-Cilag, Amgen, Gilead, AbbVie, Sanofi: Consultancy; Roche, Amgen, Gilead: Speakers Bureau. Juszczynski:Ryvu Therapeutics: Other: member of advisory board.

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DNA Methyltransferase Inhibitors Increase Expression of CD38 and Enhance Daratumumab Efficacy in Multiple Myeloma

Blood ◽

10.1182/blood-2018-99-114206 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 5618-5618 ◽

Cited By ~ 1

Author(s):

Priya Choudhry ◽

Margarette C. Mariano ◽

Arun P Wiita

Keyword(s):

Multiple Myeloma ◽

Flow Cytometry ◽

Cell Lines ◽

Research Funding ◽

Plasma Cells ◽

Cpg Island ◽

Ex Vivo ◽

Single Agent ◽

Cd38 Expression

Abstract Introduction: The anti-CD38 monoclonal antibody Daratumumab is highly effective against multiple myeloma, is well tolerated, and has high single agent activity as well as combination effects with lenalidomide-dexamethasone as well as bortezomib-dexamethasone. Patient response to daratumumab monotherapy is highly correlated with pretreatment levels of CD38 expression on MM plasma cells (Nijhof et al, Leukemia (2015) 29:2039) and CD38 loss is correlated with daratumumab resistance (Nijhof et al, Blood (2016) 128:959). As a result, there is significant interest in elucidating the regulation and role of CD38 in MM. Recently, All Trans Retinoic Acid (ATRA), a known small molecule inducer of CD38 in myeloid cells, as well as the FDA-approved histone deacetylase inhibitor panobinostat, were both demonstrated to induce CD38 in MM plasma cells leading to increased lysis by daratumumab. Examining ENCODE data, we found the presence of a CpG island at the first exon of CD38. We hypothesized that removing methylation sites from this CpG island may de-repress CD38 transcription and lead to increased CD38 protein at the cell surface in MM plasma cells. Therefore, here we studied the role of DNA methyl-transferase inhibitors (DNMTis), currently FDA-approved for treatment of myelodysplastic syndrome, as agents to potentiate daratumumab therapy. Methods: We treated MM cell lines (RPMI-8226, MM.1S, XG-1, KMS12-PE) with two different DNMTis, 5-Azacytidine and decitabine, and assessed CD38 cell surface expression by flow cytometry. Similarly, we treated MM patient bone marrow aspirates ex vivo and assessed induction of CD38 expression in the CD138 positive population by flow cytometry. We analyzed CD38 mRNA levels and total CD38 protein levels by qRT-PCR and western blotting respectively. ATRA was used as a positive control in all experiments. We further tested the functional effect of DNMTi treatment on MM cell lines using an Antibody Dependent Cell Cytotoxicity (ADCC) assay. Briefly, live treated cells were incubated overnight with daratumumab and NK92-CD16 transgenic cells at and E:T ratio of 20:1, and lysis was measured using CytoTox-Glo (Promega). Results: Flow analysis revealed that DNMTi treatment induces a 1.2-2 fold increase in CD38 surface protein expression in a dose-dependent manner across MM cell lines. DNMTi treatment consistently yielded similar or higher increases in CD38 expression than that seen in ATRA- or panobinostat-treated cells. Despite significantly lower single-agent cytotoxicity, we found that decitabine led to similar surface CD38 induction as 5-Azacytidine. By RT-qPCR, 5-Azacytidine increased CD38 mRNA expression ~3 fold versus DMSO control, compared to ~2 fold mRNA increase with ATRA. In functional ADCC assays, DNMTi treatment also led to greater lysis than ATRA. Furthermore, the combination of both DNMTi and ATRA was additive, leading to the greatest lysis by NK cells. In contrast, in ex vivo-treated patient samples, ATRA induced greater CD38 expression than 5-Azacytidine on malignant plasma cells. However, this result is expected since MM plasma cells from patients typically do not proliferate in standard ex vivo culture, and active DNA replication is a requirement for successful DNMT inhibition based on known mechanism of action. In patients, however, we anticipate that continual plasma cell proliferation will lead to effective increases in CD38 after DNMTi treatment, as found in MM cell lines here. Summary and Conclusions: Our results here demonstrate that CD38 expression in MM cells is regulated by DNA methylation and targeting DNMTs with small molecule inhibitors leads to increased vulnerability to Daratumumab treatment. We propose that combination treatment with DNMTi and Daratumumab can lead to higher efficacy of daratumumab in daratumumab-naïve MM, as well as reversal of daratumumab-resistance. These combinations should be tested in clinical trials. Disclosures Wiita: Sutro Biopharma: Research Funding; TeneoBio: Research Funding.

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Hypersialylation Protects Multiple Myeloma Cells from NK Cell-Mediated Immunosurveillance and This Can be Overcome By Targeted Desialylation Using a Sialyltransferase Inhibitor

Blood ◽

10.1182/blood-2019-126613 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 138-138

Author(s):

John Daly ◽

Subhashis Sarkar ◽

Alessandro Natoni ◽

Robert Henderson ◽

Dawn Swan ◽

...

Keyword(s):

Multiple Myeloma ◽

Sialic Acid ◽

Nk Cells ◽

Board Of Directors ◽

Cell Lines ◽

Immune Evasion ◽

Research Funding ◽

Nk Cell ◽

Advisory Committees

Introduction: Evading Natural Killer (NK) cell-mediated immunosurveillance is key to the development of Multiple Myeloma (MM). Recent attention has focused on the role of hypersialylation in facilitating immune-evasion of NK cells. Abnormal cell surface sialylation is considered a hallmark of cancer and we have implicated hypersialylation in MM disease progression. Certain sialylated glycans can act as ligands for the sialic acid-binding immunoglobulin-like lectin (Siglec) receptors expressed by NK cells (Siglec-7 and Siglec-9). These ITIM motif-containing inhibitory receptors transmit an inhibitory signal upon sialic acid engagement. We hypothesized that desialylation of MM cells or targeted interruption of Siglec expression could lead to enhanced NK cell mediated cytotoxicity of MM cells. Methodology: MM cells were treated with the sialidase neuraminidase prior to co-culture with primary NK (PNK) cells. MM cells were treated with 300µM 3Fax-Neu5Ac (sialyltransferase inhibitor) for 3 days prior to co-cultures with PNK cells. PNK cells were expanded, IL-2 activated (500U/ml) overnight, or naïve (resting). Primary MM samples/MM cell lines were screened with Siglec-7/9 chimeras (10µg/ml). PNK (IL-2 activated) cells were stained with anti-Siglec-7 and anti-Siglec-9 antibodies. Siglec-7 was targeted for knockout (KO) using the CRISPR/Cas9 system, a pre-designed guideRNA and the MaxCyteGT transfection system. MM cells were treated with 10µg/ml of Daratumumab prior to co-culture with expanded PNK cells. Results: Using recombinant Siglec-7/9 chimeras a panel of MM cell lines (MM1S, RPMI-8226, H929, JJN3 and U266) were shown to express ligands for Siglec-7 and Siglec-9 (>85%, n=3). Primary MM cells isolated from BM of newly diagnosed (n=3) and relapsed patients (n=2) were also shown to express Siglec-7 ligands (72.5±17.5%, 36.5% respectively). PNK cells express Siglec-7 and Siglec-9 (94.3±3.3% and 61±8.8% respectively, n=6). Desialylation of the MM cell lines JJN3 and H929 using neuraminidase significantly enhanced killing of MM cells by healthy donor (HD) derived PNK cells (expanded, IL-2 activated and naïve, n=7) at multiple effector:target (E:T) cell ratios. Furthermore, de-sialylation of JJN3 and H929 using neuraminidase resulted in increased NK cell degranulation (CD107α expression), compared to a glycobuffer control (n=7). De-sialylation, using 300µM 3Fax-Neu5Ac, resulted in strongly enhanced killing of MM1S by expanded HD-derived PNK cells at multiple E:T ratios (n=5, p<0.01 at 0.5:1, p<0.001 at 1:1, p<0.01 at 2.5:1). Furthermore, CD38 expression on H929 MM cells significantly increased after treatment with 300µM 3Fax-Neu5Ac for 3 days (p<0.01, n=3). In a cytotoxicity assay, expanded PNK cell-mediated antibody dependent cellular cytotoxicity (ADCC) of H929 MM cells pre-treated with Daratumumab (anti-CD38 moAb) and 3Fax-Neu5Ac was significantly higher than H929 cells pre-treated with Dara (p<0.05 at 0.5:1, p<0.01 at 1:1) or 3Fax-Neu5Ac (p<0.01 at 0.5:1, p<0.01 at 1:1) alone (n=5). Using CRISPR/Cas9, over 50% complete KO of Siglec-7 was observed on expanded PNK cells, yet did not result in enhanced NK cell-mediated cytotoxicity against either H929 or JJN3 (n=7). Siglec-9 KO using CRISPR/Cas9 is ongoing. Discussion: Hypersialylation of MM cells facilitates immune evasion and targeted removal of sialic acid strongly enhances the cytotoxicity of NK cells against MM. However, to date the role of Siglecs remains inconclusive. Nevertheless, our data suggest that targeted desialylation is a novel therapeutic strategy worth exploring in MM. In particular, upregulation of CD38 provides a strong rationale for combinatory strategies employing targeted desialylation with CD38 moAbs such as Daratumumab, with the goal of maximizing ADCC. Disclosures Sarkar: Onkimmune: Research Funding. O'Dwyer:Onkimmune: Equity Ownership, 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; BMS: Research Funding; GlycoMimetics Inc: Research Funding; AbbVie: Consultancy.

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Recurrent Non-Coding Mutations in BCL7A May Have Significant Functional Consequence in Multiple Myeloma

Blood ◽

10.1182/blood-2019-129155 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 857-857

Author(s):

Chandraditya Chakraborty ◽

Eugenio Morelli ◽

María Linares ◽

Kenneth C. Anderson ◽

Mehmet Kemal Samur ◽

...

Keyword(s):

Multiple Myeloma ◽

Cell Viability ◽

Cell Lines ◽

Chromatin Remodeling ◽

Colony Formation ◽

Ectopic Expression ◽

Advisory Board ◽

Mass Spectrometry Analysis ◽

Rna Seq

Multiple myeloma (MM) is a complex hematological malignancy characterized by gene pathway deregulations. Initial sequencing approaches have failed to identify any single frequent (>25%) mutation in the coding genome. We, therefore performed a deep (average coverage > 80X) whole genome sequencing (WGS) on 260 MM samples (208 newly diagnosed and 52 first relapse after uniform treatment) to comprehensively identify recurrent somatic alterations in non-coding regions. We have identified the most frequently involved genes affected by perturbation in neighboring non-coding region and integrate their expression using our matching deep RNA-seq data from the same patients. One of the most prominent examples is mutations in the 5' untranslated region and intron 1 of the BCL7A gene in 76% of myeloma patients. Integration of WGS with RNA-seq data confirmed significant downregulation of its expression (p values < 1e-5) in the MM cells as compared to normal plasma cells (PC). This led us to investigate the consequences of BCL-7A loss in MM. To evaluate the role of BCL7A in MM, using gain of- (GOF) and loss-of-function (LOF) approaches, we have utilized a large panel of MM cell lines with differential expression of BCL7A at the RNA and protein levels. Ectopic expression of BCL7A in a panel of 3 MM cell lines with low basal levels of BCL7a significantly reduced cell viability and colony formation over time. Inhibition of cell viability was associated with induction of apoptotic cell death in the BCL7A overexpressing cells compared to control cells. LOF studies in 3 MM cell lines with relatively higher expression of BCL7a using 3 BCL7A-specific shRNA constructs showed a more proliferative phenotype, with increased growth and viability and enhanced colony formation. The effects of BCL7A loss in MM cells were further confirmed using CRISPR-Cas9 system. BCL7a-KO cells had higher proliferative rate compared to WT cells and add back of lentiviral BCL7a plasmid reversed this effect. BCL7A is part of the SWI/SNF chromatin remodeling complex. Mutations in the genes encoding m-SWI/SNF subunits are found in more than 20% of human cancers, with subunit- and complex-specific functions. We confirmed that when expressed, BCL7A interacts with BCL11A into the SWI/SNF complex in MM cells. Comparative, mass spectrometry analysis in fact revealed SMARCC2 (BAF170), an integral subunit of SWI/SNF complex, to bind with BCL7A-BCL11A complex. However, BCL7A loss causes decreased SMARCC2 incorporation into SWI/SNF, thus suggesting that presence of BCL7A is crucial in the formation of SWI/SNF complex in MM cells and might play an important role in chromatin remodeling. Interestingly, oncogenes DEK (DNA binding oncogene) and TPD52 (tumor protein D52) involved in cancer cell proliferation and chromatin remodeling formed complex with BCL11A in BCL7A KO MM cells. Additionally, several anti-apoptotic proteins such as ANXA-1 and BCL2 are in complex with BCL11A when BCL7A is lost, suggesting the formation of an anti-apoptotic complex with consequences on MM cell survival. Currently ongoing studies are investigating the molecular mechanism of non-coding mutations impacting BCL7A expression and pathways affected by its downregulation with impact on MM cell growth and survival. In conclusion, we report biological consequences of a frequent (>75% patients) non-coding mutation in MM with cellular and molecular effects of BCL7A loss in which implicates a functional role of the m-SWI/SNF complex in driving a MM cell proliferative phenotype. Disclosures Anderson: Gilead Sciences: Other: Advisory Board; Janssen: Other: Advisory Board; Sanofi-Aventis: Other: Advisory Board; C4 Therapeutics: Other: Scientific founder ; OncoPep: Other: Scientific founder . Munshi:Abbvie: Consultancy; Abbvie: Consultancy; Amgen: Consultancy; Amgen: Consultancy; Adaptive: Consultancy; Adaptive: Consultancy; Celgene: Consultancy; Janssen: Consultancy; Janssen: Consultancy; Takeda: Consultancy; Takeda: Consultancy; Oncopep: Consultancy; Oncopep: Consultancy; Celgene: Consultancy.

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TBK1/Ikkε Inhibitor Amlx Blocks Multiple Myeloma Cell Growth in Vitro and In Vivo

Blood ◽

10.1182/blood-2018-99-119677 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 4504-4504

Author(s):

Quanhong Sun ◽

Peng Zhang ◽

Juraj Adamik ◽

Konstantinos Lontos ◽

Valentina Marchica ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

Tumor Growth ◽

Cell Lines ◽

Bone Disease ◽

Research Funding ◽

Ex Vivo ◽

Dominant Negative ◽

Induction Of Apoptosis

Abstract Multiple myeloma (MM) is the most frequent cancer to involve the skeleton and remains incurable for most patients, thus novel therapies are needed. MM bone disease is characterized by osteolytic lesions that contribute significantly to patient morbidity and mortality. We showed that TBK1 signaling is a novel pathway that increases osteoclast (OCL) formation in Paget's disease, an inflammatory bone disease. Therefore, we hypothesized that TBK1 plays a similar role in MM induction of OCL. We found that MM conditioned media (MM-CM) dose-dependently increased bone marrow monocyte (BMM) expression of activated TBK1 protein and enhanced RANKL-driven OCL formation. TBK1 knockdown by shRNA transduction into BMM significantly attenuated the ability of MM-CM to increase OCL differentiation without altering OCL differentiation in control media. We found that the TBK1/IKKε inhibitor Amlexanox (Amlx) blocked normal and MM-enhanced OCL formation. Importantly, TBK1 mRNA expression in CD138+ plasma cells (PC) isolated from MM or PC leukemia patients is significantly higher as compared to PC from Monoclonal Gammopathy of Undetermined Significance (MGUS) patients. Therefore, we tested whether targeting the TBK1/ IKKε signaling pathways would also affect MM cells. We found that Amlx strongly decreased the viability of several MM cell lines and primary MM cells via induction of apoptosis. Amlx treatment of MM cell lines also induced a G1/S blockade, decreased activated ERK1/2, and increased translation of the dominant-negative C/EBPb-LIP isoform in several MM cell lines. The positive-acting C/EBPb-LAP isoform was previously shown to be a critical transcription factor for MM viability. Importantly, Amlx also enhanced the effectiveness of the proteasome inhibitors bortezomib and carfilzomib to kill MM cells in culture. Further, Amlx sensitized MM1.S cells to the induction of apoptosis by the autophagic inhibitor Bafilomycin A. Amlx dose-dependently inhibited tumor growth in a syngeneic MM mouse model in which 5TGM1 MM cells expressing secreted GLuc were injected subcutaneously into immunocompetent C57Bl/KaLwRij. Tumor growth was assessed by measuring tumor volumes and by the levels of secreted GLuc in the blood. Further, OCL formation ex vivo from bone marrow monocytes obtained from AMLX-treated mice versus controls was decreased. Amlx did not affect the viability of primary BMM, bone marrow stromal cells (BMSC), or splenocytes. Further, Amlx treatment of primary BMSC from MM patients or normal donors decreased expression of TNFα, IL-6 and RANKL, thereby decreasing BMSC support of MM survival and OCL differentiation. Amlx pretreatment of BMSC and murine pre-osteoblast MC4 cells also decreased VCAM1 expression and reduced MM cell adhesion, another mechanism for Amlx reduction of bone microenvironmental MM support. These data suggest that targeting TBK1/IKKε signaling may decrease MM bone disease by slowing MM growth, directly and indirectly, and preventing MM-induced osteolysis. Disclosures Giuliani: Janssen Pharmaceutica: Other: Avisory Board, Research Funding; Celgene Italy: Other: Avisory Board, Research Funding; Takeda Pharmaceutical Co: Research Funding. Roodman:Amgen Denosumab: Membership on an entity's Board of Directors or advisory committees.

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Upregulation of MMP-2 & 9 by Co-Culture of Human Myeloma Cell Lines and Endothelial Cells May Be Responsible for Protection Against Cytotoxic Drugs.

Blood ◽

10.1182/blood.v108.11.5080.5080 ◽

2006 ◽

Vol 108 (11) ◽

pp. 5080-5080

Author(s):

Shankaranarayana Paneesha ◽

Raghu Adya ◽

Hemali Khanji ◽

Ed Leung ◽

C. Vijayasekar ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

Endothelial Cells ◽

Mrna Expression ◽

Cell Lines ◽

Myeloma Cell ◽

Myeloma Cells ◽

Human Myeloma Cell

Abstract Multiple myeloma is a clonal lymphoproliferative disorder characterised by the proliferation of plasma cells in the bone marrow. Inspite of good initial response, it is associated with universal relapse. We hypothesise this is due to sanctuary provided to myeloma cells by the endothelium. Matrix metalloproteinases (MMPs) are shown play a role in cell growth, invasion, angiogenesis, metastasis and bone degradation. We show here the protection offered by endothelial cells to human myeloma cell lines in in-vitro co-culture with upregulation of MMP-2 & 9 and the role of GM6001 MMP inhibitor (Ilomastat) in overcoming this protection. Human myeloma cell lines (H929, RPMI 8226, U266 & JJN3) with or without endothelial cells (human umbilical vein endothelial cells and EaHy 926 cell line) in-vitro co-culture were treated with melphalan, dexamethasone, arsenic trioxide and Ilomastat. Cytotoxicity/proliferation were assessed by the alamarBlue™ assay (Serotec) and validated by Annexin V-FITC apoptosis detection Kit (Calbiochem) and BrDU proliferation assay (BD Pharmingen™). Gelatin Zymography was used to demonstrate activity of MMP-2 & 9 in the supernatant. MMP-2 and 9 mRNA expression was quantified by Real Time Quantitative PCR (ROCHE). Co-culture of human myeloma cell lines with endothelial cells lead to increase in the proliferation of myeloma cell lines and also protected them from the cytotoxicity of chemotherapeutic agents. MMP-2 & 9 activity was upregulated by the co-culture. MMP-2 mRNA expression in human myeloma cell lines increased following 4 hr co-culture. Treatments with Ilomastat lead to the suppression of proliferation in co-culture in a dose dependent manner, associated with a reduction of MMP-2 and 9 activity. Our study shows endothelial cells offer protection to human myeloma cell lines in the presence of cytotoxic agents. This may result in the sanctuary of myeloma cells in bone marrow leading to ultimate relapse of disease. Our study also demonstrates the upregulation of MMP-2 and 9 by co-culture and increased cytotoxicity achieved by the inhibition of MMPs. Further studies are needed to determine the exact role of MMPs in myeloma biology as MMP inhibition may be an interesting therapeutic target and help in averting relapse in multiple myeloma.

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