scholarly journals Short-Term Risk for Progression in Patients with Smoldering Multiple Myeloma: The Impact of CD56 Expression

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 11-11
Author(s):  
Laura Notarfranchi ◽  
Rosanna Vescovini ◽  
Roberta Segreto ◽  
Sabrina Bonomini ◽  
Paola Storti ◽  
...  

The identification of risk factors for progression is critical in the clinical management and appropriate follow up of patients with Smoldering Multiple Myeloma (SMM). The early identification of patients with possible short-term progression to Multiple Myeloma (MM) could lead to anticipate the treatment. Several prognostic score identify in SMM patients the main risk factors for progression to MM. The two most used risk stratification models in SMM are the Mayo Clinic model, based on the tumor burden and the free light chains ratio, and the Spanish PETHEMA group model based on the immunophenotyped to identify abnormal plasma cells (PCs) and the reduction of the unevolved immunoglobulins. However, significant discrepancies between these two clinical models currently used in clinical practice has been recently underlined. For this reason, new parameters to identify possible new parameters for progression in SMM need to be defined. The aim of this study was to validate the main prognostic score and to investigate the possible role of the immunphenotype as risk factor for progression in a monocentric cohort of patients with SMM. We retrospectively evaluated a cohort of SMM patients admitted to a single haematological center (Hematology and BMT Unit, University Hospital of Parma) between 2014 and 2018. We analyzed a total cohort of 80 patients diagnosed with SMM according to the IMWG recently updated diagnostic criteria. All patients analysed underwent to Bone Marrow (BM) examination and imaging evaluation was performed in order to exclude the presence of bone disease and/or focal lesions. Both immunophenotypic and FISH analysis were performed of BMPCs. The median age of the SMM patients analysed was 68 years (range 36-93 years). Median percentage of BMPCs was 15% (range 10-40%) in the entire population. Median serum M-protein was 2 g/dL (range: 0.17-4.5). FLC ratio value was available in 66 patients: in 47 (71%) the ratio was unbalanced, 26 (39%) had a FLC ratio ≤ 0.125 or ≥ 8 and in 6 (9%) it was > 20. The presence of a reduction of one or two uninvolved immunoglobulins occurred in 61% of the entire population. The median follow up time was 27 months (range 0 - 76 months) for whole population. Overall 22 patients of the entire cohort progressed to MM with a median the time to progression (TTP) of 22 months. Firstly, we validated the currently score of progression in our cohort of SMM patients. By univariate analysis we found that percentage of BMPCs, abnormal FLC ratio and presence of immunoparesis were significantly correlated with progression to active MM (p<0.005 for each variable). Any significant correlation was not observed with age, sex, Ig isotype and light chain's type (p=NS). Afterwards, we study and confirm the significance of the risk stratification models. "Pethema" (p=0.0002), "20-2-20" Mayo score (p=0.0005) and also the "Danish score" (p= 0.0173) turned out statistically significant. Then, we investigate the possible role of immunophenotype in the risk of progression. Dividing the population-based on CD56 expression, we found that the median TTP in CD56- SMM patients was 21 months as compared to 34 months in CD 56+ SMM patients (p= 0.08). Moreover CD56- patients progressed without a significant increase of the monoclonal component (p=0.48) as compared to those CD56+ SMM patients (p=0.023). Finally, a relationship between CD56 expression and the hyperdiploidy was wound finding that CD56- SMM patients had a significant lower presence of hyperdiploidy as compared to those with CD56+ BMPCs (p=0.024) In conclusion, our data indicate that in SMM patients the factors, which mostly impact on the short-term risk of progression to active MM, are the entity of the PCs infiltrate, the immunoparesis and abnormal FLC ratio. Therefore, we identified the absence of CD56 expression by BMPCs as a possible factor for a more aggressive disease regardless to the tumoral burden. Disclosures Giuliani: Celgene: Membership on an entity's Board of Directors or advisory committees, Other: Participation in congresses, Research Funding; Janssen Pharmaceutical: Membership on an entity's Board of Directors or advisory committees, Other: Clinical study sponsorship; participation in congresses, Research Funding; Millennium Pharmaceutical: Other: Clinical study sponsorship, Research Funding; GSK: Other: Clinical study sponsorship, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Other: Participation in congresses.

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 136-136
Author(s):  
Ze Tian ◽  
Jian-Jun Zhao ◽  
Jianhong Lin ◽  
Dharminder Chauhan ◽  
Kenneth C. Anderson

Abstract Abstract 136 Investigational Agent MLN9708 Target Tumor Suppressor MicroRNA-33b in Multiple Myeloma Cells Ze Tian, Jianjun Zhao, Jianhong Lin, Dharminder Chauhan, Kenneth C. Anderson Medical Oncology, Dana Farber Cancer Institute and Harvard Medical School, Boston, MA, 02115 MicroRNAs (miRNAs) are 19–25 nucleotide-long noncoding RNA molecules that regulate gene expression both at the level of messenger RNA degradation and translation. Emerging evidence shows that miRNAs play a critical role in tumor pathogenesis by functioning as either oncogene or tumor suppressor genes. The role of miRNA and their regulation in response to proteasome inhibitors treatment in Multiple Myeloma (MM) is unclear. Here, we utilized MLN9708, a selective orally bio-available proteasome inhibitor to examine its effects on miRNA alterations in MM.1S MM cells. Upon exposure to aqueous solutions or plasma, MLN9708 rapidly hydrolyzes to its biologically active form MLN2238. Our previous study using both in vitro and in vivo models showed that MLN2238 inhibits tumor growth and triggers apoptosis via activation of caspases. Moreover, MLN2238 triggered apoptosis in bortezomib-resistant MM cells, and induced synergistic anti-MM activity when combined with HDAC inhibitor SAHA, dexamethasone, and lenalidomide. In the current study, we treated MM.1S cells with MLN2238 (12 nM) for 3 hours and harvested; total RNA was subjected to miRNA profiling using TaqMan® Array Human miRNA A-Card Set v3.0 and the data was analyzed using dChip analysis. Results showed that MLN2238 modulates miRNA expression with a total of 36 miRNA changing their expression profiling (δδCT>1.5 or δδCT <-1.5; 19 were upregulated and 17 showed a downregulation). Among all miRNA, miR-33b was highly (δδCT>7) upregulated in response to MLN2238 treatment. We therefore hypothesized that miR-33b may play a role in MM pathogenesis as well as during MLN2238-induced proteasome inhibition in MM cells. We first utilized quantitative polymerase chain reaction (q-PCR) to validate the changes in miRNA expression profiling. Results confirmed that MLN2238 treatment triggers significant increase in the miR-33b expression in MM.1S cells (2.1 and 2.2 folds at 3h and 6h, respectively; P<0.001). Examination of normal PBMCs and plasma cells showed higher expression of miR-33b than patient MM cells (P<0.001). We further investigated the functional role of miR-33b in MM cells at baseline and during MLN2238 treatment. Drug sensitivity, cell viability, apoptosis, colony formation, and migration assays were performed using cell TilTer-Glo, Annexin V-FITC/PI staining, MTT staining, and Transwell assays, respectively. Signaling pathways modulated post miR-33b overexpression were evaluated by q-PCR, immunoblot, and reporter assays. Our findings show that overexpression of miR-33b significantly decreased cell viability, cell migration, colony formation, as well as increased apoptosis and sensitivity of MM cells to MLN2238 treatment. Targetscan analysis predicted pim-1 as a putative downstream target of miR-33b. Overexpression of miR-33b downregulated pim-1 mRNA and protein expression. To further corroborate these data, we co-tranfected miR-33b and Pim-1-wt or Pim-1-mt in 293T and MM.1S cell lines. In concert with our earlier findings, miR-33b decreases pim-1-wt, but not pim-1-mt reporter activity in both cell lines. Reflecting the overexpression study results, MLN2238 treatment also decreases pim-1-wt, but not pim1-mt reporter activity. Moreover, a biochemical inhibitor of pim1/2 triggered apoptosis in MM cells. Finally, overexpression of miR-33b inhibits tumor growth (P<0.001) and prolongs survival (P<0.001) in both subcutaneous and disseminated human MM xenograft models. In summary, our study suggests that miR-33b is a tumor suppressor, which plays a role during MLN2238-induced apoptotic signaling in MM cells, and provide the basis for novel therapeutic strategies targeting miR-33b in MM. Disclosures: Anderson: Millennium: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees; Acetylon: Equity Ownership.


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2077-2077
Author(s):  
Cristina Panaroni ◽  
Ka Tat Siu ◽  
Keertik S Fulzele ◽  
Janani Ramachandran ◽  
Noopur Raje

Abstract Multiple Myeloma (MM) is a plasma cell tumor that originates and expands within bone marrow (BM). MM occurs primarily later in life with a median age at diagnosis in the seventh decade characterized by loss of bone tissue due to osteolytic lesions. Recent studies have suggested a positive correlation of MM with obesity. BM fat cells originate, as bone cells, from a common progenitor called Mesechymal Stem Cell (MSC). MSC commitment into osteoblastic or adipose lineage is regulated by two major signaling pathways: Wnt signaling, which promotes bone formation, and PPARγ signaling, responsible for adipocyte differentiation. Adipogenesis and osteogenesis are inversely correlated processes, thus a signaling imbalance favoring differentiation towards one lineage will tilt this critical balance. In fact, the amount of marrow adiposity increases with age such that it is 30% of the BM volume in young adults but rises up to 70% in elderly people while bone formation reduces with age. We have recently demonstrated that MM patients have increased levels of a Wnt-signaling inhibitor sclerostin (SOST) and patient MSC differentiation into osteoblastic cells is improved in the presence of a SOST neutralizing antibody (Eda et al. JBMR 2015). Sclerostin is secreted by osteolineage cells and has also been shown to increase adipogenesis of an adipogenic cell line 3T3-L1 (Ukita et al. JCB 2016). However, the role of SOST on BM adipose tissue in MM patients has not been investigated. Here we show that elevated SOST levels, induced by MM cells, increase BM adipogenesis which, in turn, supports MM progression. To assess the role of MM cells on MSC differentiation into adipocytes, MSCs from patients and normal donors (ND) were differentiated in vitro in the presence or absence of MM.1S, a human MM cell line. Presence of MM.1S cells significantly reduced osteogenic differentiation of MSCs as assessed by quantitative and qualitative Alizarin Red S staining; by contrast, the presence of MM.1S cells significantly enhanced adipogenesis in the MSCs as assessed by Oil Red O staining quantification. At the molecular level, we observed a 2-fold increase in PPARγ gene expression in MSCs from MM patients when compared to ND samples at baseline and a 5-fold increase when MSCs from patients and NDs were cultured for 72 hours in the presence of MM.1S in trans-well. To evaluate the role of SOST on BM adiposity, we intraperitoneally injected recombinant SOST, or PBS as control, into wild-type (WT) mice daily for 3 weeks. At the end of the treatment, mice treated with SOST showed a significant increase in BM adiposity. To validate MM cell induced adipogenesis in in-vivo settings, we injected MM.1S cells into the SCID-hu immunodeficient mouse model. Four weeks after cell injection, increased BM adipocytes were observed in MM.1S treated immunodeficient mice. Interestingly, when mice injected with MM.1S cells were treated for 3 weeks with SOST neutralizing antibody the level of BM adiposity returned to the healthy control levels. Finally, MM cell engraftment and tumor development was analyzed in SOST knock-out (KO) mice. While both SOST KO and WT animals showed MM cell engraftment and extramedullary plasmacytoma formation, preliminary results suggest a lower level of MM cell engraftment in BM of SOST KO mice. Our data suggest that sclerostin secretion increases BM adipogenesis supporting MM cell growth and survival and therefore may play a critical role in the development and progression of MM. Disclosures Raje: Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Merck: Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Research Funding; Eli Lilly: Research Funding.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 4341-4341
Author(s):  
Fengjuan Fan ◽  
Stefano Malvestiti ◽  
Yujia Shen ◽  
Eugenio Morelli ◽  
Yuji Mishima ◽  
...  

A significant increase in bone marrow (BM) angiogenesis represents a key event in early, microenvironment-dependent, multiple myeloma (MM). Angiogenic growth factor- and cytokine- production and secretion is a complex process regulated by a plethora of transcription factors (TFs). Over the past years, members of the AP-1 family of TFs have emerged as potential new therapeutic targets. Our recent work demonstrated for the first time a pivotal role for the AP-1 family member JunB in MM pathogenesis (Fan et al., 2017). Whether JunB also contributes to MM BM angiogenesis is currently unknown. In silico and immunohistochemical analyses revealed a correlative increase of JunB and angiogenic growth factors in samples isolated from healthy donors to MGUS and MM patients; and a decrease in samples isolated from patients with plasma cell leukemia. These data were supported by the utilization of an innovative in vivo MM model of clonal evolution. Specifically, JunB as well as selected angiogenic factors were significantly increased in tumor cell clones at primary sites (bone chips) versus tumor cell clones at metastatic (distant BM) sites, as evidenced by whole exome and RNA sequencing. Functionally, doxycyclin- induced inhibition of stroma cell: MM cell co-culture- as well as of IL-6- mediated JunB upregulation in TetR-shJunB/ MM.1S cells significantly reduced production and secretion of angiogenic factors; and consequently inhibited in vitro angiogenesis. Conversely, 4-hydroxytamoxifen (4-OHT)-mediated upregulation of JUNB activity in JUNB-ER/MM cells strongly increased the expression and secretion of angiogenic factors and in vitro angiogenesis. The interaction of JunB with angiogenic factor- encoding DNA in MM cells was further confirmed utilizing chromatin immunoprecipitation (ChIP)- sequencing. Finally, treatment with doxycycline effectively inhibited JunB levels and consistently reduced microvessel density in immunodeficient NSG mice inoculated with TetR-shJUNB/ MM.1S, but not TetR-SCR/ MM.1S. In conclusion, our findings demonstrate a pivotal role of JUNB in MM BM angiogenesis; they thereby provide further evidence that JUNB is a promising therapeutic target particularly in early MM. Disclosures Vallet: Pfizer: Honoraria; Roche Pharmaceuticals: Consultancy; MSD: Honoraria. Roccaro:Associazione Italiana per al Ricerca sul Cancro (AIRC): Research Funding; Associazione Italiana per al Ricerca sul Cancro (AIRC): Research Funding; AstraZeneca: Research Funding; Transcan2-ERANET: Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Transcan2-ERANET: Research Funding; AstraZeneca: Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees; European Hematology Association: Research Funding; European Hematology Association: Research Funding. Goldschmidt:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; John-Hopkins University: Research Funding; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; MSD: Research Funding; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Mundipharma: Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Adaptive Biotechnology: Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Research Funding; Dietmar-Hopp-Stiftung: Research Funding; John-Hopkins University: Research Funding; Chugai: Honoraria, Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Research Funding; Molecular Partners: Research Funding. Podar:Takeda: Consultancy; Celgene: Consultancy, Honoraria; Amgen Inc.: Honoraria; Janssen Pharmaceuticals: Consultancy, Honoraria; Roche Pharmaceuticals: Research Funding.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 723-723
Author(s):  
Shankara Anand ◽  
Mark Bustoros ◽  
Romanos Sklavenitis-Pistofidis ◽  
Robert A. Redd ◽  
Eileen M Boyle ◽  
...  

Abstract Introduction: Multiple Myeloma (MM) is an incurable plasma cell malignancy commonly preceded by the asymptomatic stage smoldering multiple myeloma (SMM). MM is characterized with significant genomic heterogeneity of chromosomal gains and losses (CNVs), translocations, and point mutations (SNVs); alterations that are also observed in SMM patients. However, current SMM risk models rely solely on clinical markers and do not accurately capture progression risk. While incorporating some genomic biomarkers improves prediction, using all MM genomic features to comprehensively stratify patients may increase risk stratification precision in SMM. Methods: We obtained a total of 214 patient samples at SMM diagnosis. We performed whole-exome sequencing on 166 tumors; of these, RNA sequencing was performed on 100. Targeted capture was done on 48 additional tumors. Upon binarization of DNA features, we performed consensus non-negative matrix factorization to identify distinct molecular clusters. We then trained a random forest classifier on translocations, SNVs, and CNVs. The predicted clinical outcomes for the molecular subtypes were further validated in an independent SMM cohort of 74 patients. Results: We identified six genomic subtypes, four with hyperdiploidy (&gt;48 chromosomes, HMC, HKR, HNT, HNF) and two with IgH translocations (FMD, CND) (Table 1). In multivariate analysis accounting for IMWG (20-2-20) clinical risk stages, high-risk (HMC, FMD, HKR) and intermediate-risk (HNT, HNF) genetic subtypes were independent predictors of progression (Hazards ratio [HR]: 3.8 and 5.5, P = 0.016 and 0.001, respectively). The low-risk, CND subtype harboring translocation (11;14) was enriched for the previously defined CD-2 MM signature defined by the B cell markers CD20 and CD79A (FDR = 0.003 ), showed upregulation of CCND1, E2F1, and E2F7 (FDR = 0.01, 0.0004, 0.08), and was enriched for G2M checkpoint, heme metabolism, and monocyte cell signature (FDR = 0.003, 0.003, 0.003, respectively). The FMD subtype with IgH translocations (4;14) and (14;16) was enriched for P53, mTORC1, unfolded protein signaling pathways and plasmacytoid dendritic cell signatures (FDR = 0.01, 0.005, 0.008, respectively). The HKR tumors were enriched for inflammatory cytokine signaling, MYC target genes, T regulatory cell signature, and the MM proliferative (PR) signatures (FDR = 0.02, 0.03, 0.007, 0.02, respectively). The APOBEC mutational signature was enriched in HMC and FMD tumors (P = 0.005), while there was no statistical difference across subtypes in the AID signature. The median follow-up for the primary cohort is 7.1 years. Median TTP for patients in HMC, FMD, and HKR was 3.8, 2.6, and 2.2 years, respectively; TTP for HNT and HNF was 4.3 and 5.2, respectively, while it was 11 years in CND patients (P = 0.007). Moreover, by analyzing the changes in MM clinical biomarkers over time, we found that patients from high-risk subgroups had higher odds of developing evolving hemoglobin and monoclonal protein levels over time (P = 0.01 and 0.002, respectively); Moreover, the absolute increase in M-protein was significantly higher in patients from the high-risk genetic subtypes at one, two, and five years from diagnosis (P = 0.001, 0.03, and 0,01, respectively). Applying the classifier to the external cohort replicated our findings where intermediate and high-risk genetic subgroups conferred increased risk of progression to MM in multivariate analysis after accounting for IMWG staging (HR: 5.5 and 9.8, P = 0.04 and 0.005, respectively). Interestingly, within the intermediate-risk clinical group in the primary cohort, patients in the high-risk genetic subgroups had increased risk of progression (HR: 5.2, 95% CI 1.5 - 17.3, P = 0.007). In the validation cohort, these patients also had an increased risk of progression to MM (HR: 6.7, 95% CI 1.2 - 38.3, P = 0.03), indicating that molecular classification improves the clinical risk-stratification models. Conclusion: We identified and validated in an independent dataset six SMM molecular subgroups with distinct DNA alterations, transcriptional profiles, dysregulated pathways, and risks of progression to active MM. Our results underscore the importance of molecular classification in addition to clinical evaluation in better identifying high-risk SMM patients. Moreover, these subgroups may be used to identify tumor vulnerabilities and target them with precision medicine efforts. Figure 1 Figure 1. Disclosures Bustoros: Janssen, Bristol Myers Squibb: Honoraria, Speakers Bureau; Takeda: Consultancy, Honoraria. Casneuf: Janssen: Current Employment. Kastritis: Amgen: Consultancy, Honoraria, Research Funding; Takeda: Honoraria; Pfizer: Consultancy, Honoraria, Research Funding; Genesis Pharma: Honoraria; Janssen: Consultancy, Honoraria, Research Funding. Walker: Bristol Myers Squibb: Research Funding; Sanofi: Speakers Bureau. Davies: Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Roche: Consultancy, Honoraria; Janssen: Consultancy, Honoraria. Dimopoulos: Amgen: Honoraria; BMS: Honoraria; Takeda: Honoraria; Beigene: Honoraria; Janssen: Honoraria. Bergsagel: Genetech: Consultancy, Honoraria; Oncopeptides: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Patents & Royalties: human CRBN mouse; GSK: Consultancy, Honoraria; Celgene: Consultancy, Honoraria. Yong: BMS: Research Funding; Autolus: Research Funding; Takeda: Honoraria; Janssen: Honoraria, Research Funding; Sanofi: Honoraria, Research Funding; GSK: Honoraria; Amgen: Honoraria. Morgan: BMS: Membership on an entity's Board of Directors or advisory committees; Jansen: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; GSK: Membership on an entity's Board of Directors or advisory committees. Getz: IBM, Pharmacyclics: Research Funding; Scorpion Therapeutics: Consultancy, Current holder of individual stocks in a privately-held company, Membership on an entity's Board of Directors or advisory committees. Ghobrial: AbbVie, Adaptive, Aptitude Health, BMS, Cellectar, Curio Science, Genetch, Janssen, Janssen Central American and Caribbean, Karyopharm, Medscape, Oncopeptides, Sanofi, Takeda, The Binding Site, GNS, GSK: Consultancy.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 138-138
Author(s):  
John Daly ◽  
Subhashis Sarkar ◽  
Alessandro Natoni ◽  
Robert Henderson ◽  
Dawn Swan ◽  
...  

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 (&gt;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&lt;0.01 at 0.5:1, p&lt;0.001 at 1:1, p&lt;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&lt;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&lt;0.05 at 0.5:1, p&lt;0.01 at 1:1) or 3Fax-Neu5Ac (p&lt;0.01 at 0.5:1, p&lt;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.


Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 951-951 ◽  
Author(s):  
Abdel Kareem Azab ◽  
Phong Quang ◽  
Feda Azab ◽  
Costas M Pitsillides ◽  
John T Patton ◽  
...  

Abstract Abstract 951 INTRODUCTION: Multiple Myeloma (MM) is characterized by widespread disease at diagnosis with the presence of multiple lytic lesions and disseminated involvement of the bone marrow (BM), implying that the progression of MM involves a continuous re-circulation of the MM cells in the peripheral blood and re-entrance into the BM. Selectins are adhesion molecules expressed by activated endothelium of venules and leukocytes, and are involved in the primary interaction of lymphocytes with the endothelium of blood vessels. The binding of selectins serves as a biologic brake, making leukocyte quickly decelerate by rolling on endothelial cells, as the first step of extravasation. In this study, we have investigated the role of selectins and their ligands in the regulation of homing of MM Cells to the BM and the therapeutic implications of this role. METHODS AND RESULTS: We have used flow cytometry to characterize the expression of E, L and P-selectins and their ligands on MM cell lines, patient samples and on plasma cells from normal subjects. We found that all MM cell lines and patient samples showed high expression of L and P, but little of no E-selectin. While normal plasma cells showed low expression of all selectins and ligands.(give numbers) A pan-selectin inhibitor GMI-1070 (GlycoMimetics Inc., Gaithersburg, MD) inhibited the interaction of recombinant selectins with the selectin-ligands on the MM cells in a dose response manner. We have tested the role of the selectins and their ligands on the adhesion of MM cells to endothelial cells and found that MM cells adhered preferentially to endothelial cells expressing P-selectin compared to control endothelial cells and endothelial cells expressing E-selectin (p<0.05). Moreover, we found that blockade of P-selectin on endothelial cells reduced their interaction with MM cells (p<0.01), while blockade of E and L-selectin did not show any effect. Treating endothelial cells with GMI-1070 mimicked the effect of blocking P-selectin. Moreover, we found that treating endothelial cells with the chemokine stroma cell-derived factor-1-alpha (SDF1) increased their expression of P but not E or L-selectin detected by flow cytometry. Neither the blockade of each of the selectins and their ligands nor the GMI-1070 inhibited the trans-well chemotaxis of MM cells towards SDF1-alpha. However, blockade of P-selectin (p<0.001) on endothelial cells by GMI-1070 inhibited the trans-endothelial chemotaxis of MM cells towards SDF1-alpha. Both adhesion to endothelial cells and activation with recombinant P-selectin induced phosphorylation of cell adhesion related molecules including FAK, SRC, Cadherins, Cofilin, AKT and GSK3. GMI-1070 decreased the activation of cell adhesion molecules induced by both recombinant P-selectin and endothelial cells. Using in vivo flow cytometry we found that both anti P-selectin antibody and GMI-1070 prevented the extravasation of MM cells out of blood vessels into the bone marrow in mice. Moreover, we found that, in a co-culture system, endothelial cells protected MM cells from bortezomib induced apoptosis, an effect which was reversed by using GMI-1070, showing synergistic effect with bortezomib. CONCLUSION: In summary, we showed that P-selectin ligand is highly expressed in MM cells compared to normal plasma cells, and that it plays a major role in homing of MM cells to the BM, an effect which was inhibited by the pan-selectin inhibitor GMI-1070. This provides a basis for testing the effect of selectin inhibition on tumor initiation and tumor response to therapeutic agents such as bortezomib. Moreover, it provides a basis for future clinical trials for prevention of MM metastasis and increasing efficacy of existing therapies by using selectin inhibitors for the treatment of myeloma. Disclosures: Patton: GlycoMimetics, Inc: Employment. Smith:GlycoMimetics, Inc: Employment. Sarkar:GlycoMimetics, Inc: Employment. Anderson:Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Millennium: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Magnani:GlycoMimetics, Inc.: Employment. Ghobrial:Millennium: Honoraria, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau.


Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 2705-2705
Author(s):  
Lisa Schafranek ◽  
Eva Nievergall ◽  
Jason A. Powell ◽  
Devendra K. Hiwase ◽  
Deborah L. White ◽  
...  

Abstract Introduction Bcr-Abl1 is necessary and sufficient to cause chronic myeloid leukemia (CML) and as such CML cells are dependent on Bcr-Abl signalling for survival. Targeting CML cells with tyrosine kinase inhibitors (TKIs) commits cells to apoptotic cell death. Bcr-Abl constitutively activates STAT5, however the role of JAK-2 in the activation of STAT5 by Bcr-Abl is controversial. Recent studies of transient Bcr-Abl inhibition indicate that residual low levels of TKI are sufficient to maintain STAT5 inhibition in the absence of sustained Bcr-Abl inhibition. Therefore STAT5 is a highly sensitive measure of kinase activity. We hypothesized that sustained blockade of STAT5 is essential for the commitment of CML cells to apoptosis following inhibition of Bcr-Abl by TKIs. Aim To determine the role of STAT5 and JAK inhibition in the commitment of CML cells to apoptosis. Methods Factors required for CML cell death were examined in the setting of transient inhibition of Bcr-Abl by TKIs. Induction of apoptosis was assessed by Annexin V/7AAD and the clonogenic potential of CML progenitors assessed by CFU-GM assay. Bcr-Abl and apoptotic signaling pathways were interrogated by western blotting and flow cytometry. Dasatinib was used at 100 nM for potent inhibition of Bcr-Abl. Short term refers to 30 min exposure. Standard washout refers to 3 consecutive washes following potent TKI treatment. Optimal washout refers to 3 washes with 1 h equilibration at 37°C in drug free media between washes. Results In BCR-ABL+ cell lines short term, potent dasatinib exposure followed by optimal washout resulted in reactivation of Bcr-Abl and STAT5, inhibition of apoptosis (83% viable, n=3) and maintenance of colony formation in CML progenitors (CFU-GM: 85% of untreated n=3). Plasma concentrations of dasatinib vary between patients, however peak plasma levels occur up to 6 h after dosing and dasatinib remains available for up to 24 h. CML cell lines and CP-CML CD34+ progenitors were exposed to 100 nM dasatinib for 0.5-8 h before optimal washout. Cell death was achieved if TKI exposure by at least 4 h, with maximal cell death (15% viable, n=3, p=0.008) and reduction of colonies (30.1% of control, p=0.002) achieved after 8 h exposure. Comparison of 30 min and 8 h exposures to 100 nM dasatinib followed by optimal washout was performed to assess the critical signalling components required to induce apoptosis. Reactivation of Bcr-Abl, STAT5 and Erk occurred upon washout following both the 30 min and 8 h exposures, however the 8 h exposure resulted in the inhibition of STAT5 and loss of expression of STAT5 targets Mcl-1 and Bcl-xl, but not Bcl-2. In CP-CML CD34+ cells, prolonged inhibition of STAT5 was observed after 4 h exposure, following optimal washout, highlighting loss of STAT5 activity as potentially critical to irreversible induction of cell death. Continuous inhibition of STAT5 alone with pimozide (Pz) or the specific inhibitor N’-((4-Oxo-4H-chromen-3-yl)methylene)nicotinohydrazide (herein referred to as STAT5i) led to minimal apoptosis (73% and 75% viable, respectively, n=3) when used alone. However, when combined with 30 min exposure to dasatinib (100 nM) STAT5 inhibition proved lethal in a proportion of cells despite optimal washout (57% viable +Pz and 59% +STAT5i). The clonogenic potential CML progenitors was also significantly reduced (12%, p=0.002 and 18% CFU, p=0.003) (Figure 1). The JAK1/2 kinase inhibitor ruxolitinib was used to assess the involvement of JAK1/2 in Bcr-Abl-dependent activation of STAT5. Similar to the observations with STAT5 inhibition, ruxolitinib had minimal effect on cell death as a sole agent (74% viable). However, in contrast to our observations with STAT5 inhibition, the addition of ruxolitinib to 30 min 100 nM dasatinib exposure did not induce additional cell death (70% viable, p=0.41, n=3). Conclusion STAT5 is a critical component of the time-dependent sensitivity of CML cells to TKI treatment in a Bcr-Abl-dependent, but JAK-independent manner. In contrast to previous studies describing JAK2 as a promising secondary target for the enhancement of TKI treatment of CML, we demonstrate that inhibition of STAT5 in conjunction with standard TKI therapy is a promising therapeutic strategy for the treatment of CML. Disclosures: Nievergall: CSL: Research Funding. White:Novartis: Research Funding; BMS: Research Funding, Speakers Bureau; Ariad: Research Funding; CSL: Research Funding. Hughes:Novartis: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding; BMS: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding; Ariad: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding; CSL: Research Funding.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 4580-4580 ◽  
Author(s):  
Eduardo Sobejano ◽  
Veronica Gonzalez De La Calle ◽  
Victor Higuero ◽  
Fernando Escalante ◽  
Ramón García-Sanz ◽  
...  

INTRODUCTION The t (11; 14) by fluorescent in situ hybridization (FISH) is found in 15-20% of patients with multiple myeloma (MM) . Although it was classically considered a standard risk translocation or even a good prognosis, recent studies conducted in the era of new drugs show contradictory results and it is not well established if they have to be considered intermediate or standard risk. The possibility of using targeted therapy with venetoclax for patients harboring t(11;14) makes the investigation of the outcome of newly diagnosed multiple myeloma (NDMM) with t(11;14) as relevant. METHODS We analyzed the baseline characteristics and outcome of patients with t(11;14)and receiving HDT-ASCT within the series of 647 patients with NDMM between 1988 and 2018 according to the current criteria at each moment at two academic hospitals in Spain (University Hospital of Salamanca and Hospital of Leon) . The FISH was performed on selected cells according to international regulations and centralized at the University Hospital of Salamanca. For this purpose, a descriptive cross-sectional study was first conducted comparing the characteristics of patients with t (11; 14) versus the rest. The final objective wasto evaluate the role of HDT-ASCT in NDMM with t(11;14). RESULTS The baseline characteristics of the whole series were: a median age of 71years (yrs) (range:30-96). 217 patients (33,5%) were under 65 years. 352 (56.2%) were IgG; 161 (25.7%) IgA; 87 (13.9%) Bence Jones; 19 (3%) non-secretors, and 5 and 2 cases were IgD and IgM, respectively. 320 (53.2%) received novel agents as part of the first line of therapy. Overall, 153 (27.8%) achieved complete response (CR) after first line, and 403 (73.1%) at least a partial response. After a median follow-up for living patients of 4.26 yrs (range: 0,1-27.3), the OS of the entire series was 2.74 years. T(11;14) was performed in 440 NDMM patients and was positive in 80 (18.2%). Only in 5 patients other high-risk alterations (t (14:16), t (4:14) or del17p (p53)) were detected. The baseline characteristics of patients with and without t (11:14) did not show significant differences, except for the heavy chain pattern(p <0,001). IgA was lower in patients with t(11:14) 12,8% (10 out of 78)vs 27,7% (98 out of 353). Of note, most patients with non-secretory MM (10 out of 16, 62,5%) had the t(11;14) whilst in the conventional secretory MM patients, t(11;14) was observed in 68out of 415(16,4%). In addition, the plasma cell bone marrow infiltration was significantly higher in patients with t(11;14)(> 60% Plasma Cells) 32.8% vs 13.3%(p <0.001)). HDT-ASCT was performed in 162 patients (25%)and 22 of them (13,5%) were positive for the t(11:14) and only in 2 patients, other high-risk alterations were detected.The induction therapy received in both treatments arms was homogeneous basically consisted on combinations of proteasome inhibitors plus immunomodulatory drugs. The median OS for NDMM patients undergoing ASCT was 4,33 years. (range: 0,47-26,85) and the median PFS for this patients was 2,25 yrs (range: 0,1-27,25) The median PFS for patients with t (11/14) undergoing ASCT trended to be higher than that observed in patients without t(11;14) who received also HDT-ASCT (99.1 vs 54.9 months), without obtaining significant results, (p 0.205) maybe due to the small number of patients (Figure 1).The median OS in the group of patients with and without t(11:14) undergoing ASCT was 120,8 vs 140 months (p= 0,829). In the cohort of non eligible ASCT patients both median PFS and OS for patients with t(11:14) was similar than that observed in patients without t(11:14)(median PFS of 19,9 vs 19,4 months) (p 0,438) and (median OS of 31,5 vs 44 months) (p 0,424), respectively. CONCLUSION T(11;14) seems to be a cytogenetic abnormality more frequently observed in patients with NDMM and non secretory phenotype what requires further investigation. Patients with t(11;14) benefit the most if they received HDT-ASCT and it would represent a therapeutic strategy of choice if the patient is transplant-eligible. Figure 1 Disclosures Puig: Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Research Funding; The Binding Site: Honoraria; Takeda, Amgen: Consultancy, Honoraria. Mateos:Abbvie: Membership on an entity's Board of Directors or advisory committees; GSK: Membership on an entity's Board of Directors or advisory committees; Pharmamar: Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive: Honoraria; EDO: Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 576-576 ◽  
Author(s):  
Even H Rustad ◽  
Venkata Yellapantula ◽  
Dominik Glodzik ◽  
Gunes Gundem ◽  
Daniel A. Leongamornlert ◽  
...  

Whole genome sequencing (WGS) studies have started to reveal the critical role of structural variants (SVs) in multiple myeloma (MM) pathogenesis and evolution. We have recently revealed the existence of three main classes of complex events in 30 MM patients: chromothripsis, chromoplexy and templated insertions (Maura F et al, Nat Comm, 2019). Here, drawing on a large cohort of 768 MM patients enrolled in the MMRF CoMMpass study (NCT01454297), we comprehensively characterized the landscape of SVs and their functional implications. Low coverage long-insert WGS (median 4-8X) was available from all patients, of whom 591 also had RNAseq data. Overall, we identified a median of 15 total SVs (range 1-253). Fifty-one percent of SVs (n = 8766) were defined as part of complex events, with a median of one per patient (range 0-14). Chromothripsis, chromoplexy and templated insertions involving &gt;2 chromosomes were observed in 21%, 11% and 21 %, respectively. Chromothripsis was the only SV class with clear prognostic implications after adjustment for molecular and clinical features, resulting in adverse PFS (adjusted HR = 1.57; 95% CI 1.13-2.22; p = 0.008) and OS (adjusted HR = 2.4; 95% CI 1.5-3.83; p &lt; 0.001). Templated insertions emerged as the cause of CCND1-IGH and MYC translocations in 34 % and 73 % of cases, respectively. This is particularly important given the capability of templated insertions to connect and amplify multiple regions of the genome, involving several oncogenes and regulatory regions (e.g. super enhancers). Twenty-four patients (3.1 %) had translocation between an immunoglobulin locus and a non-canonical driver gene (e.g. PAX5, CD40 and MAP3K14), showing outlier expression by RNAseq where available. SV hotspot analysis was carried out using the Piecewise Constant Fitting algorithm, comparing the local SV breakpoint density to an empirical background model (Glodzik et al, Nat Genet, 2017). To identify functionally important hotspots, we integrated: 1) local cumulative copy number data, 2) amplification and deletion peaks identified by GISTIC v2 (q &lt; 0.1), 3) gene fusion data and 4) differential expression analysis with adjustment for main molecular subgroups (limma; Bonferroni-Holm adjusted p-values &lt; 0.01). Ninety-eight hotspots were identified (Figure 1), of which 71 (72%) have not previously been reported. Among these novel hotspots, 23 (33 %) contained a known or suspected driver gene, including TNFRSF17 (encoding CAR-T target BCMA), SYK (BCR signal transduction) and KLF2 (key myeloma transcription factor and germline predisposition locus). Active enhancer regions were present in 29 of the novel hotspots (41 %), including 65 % of those with a concurrent putative driver gene involved. For 34 hotspots (48 %) no clear target gene or regulatory region emerged. SV hotspots and GISTIC peaks covered 13 % of the genome. Overall 38 % of simple and complex SVs had at least one breakpoint falling within a recurrently involved region. The majority of chromoplexy, chromothripsis and templated insertions involved recurrent regions (64, 76 and 86 %, respectively). Simple events were most commonly rare, ranging from 74 % of deletions to 45 % for translocations. Quantifying the global functional impact of the remaining 72 % of non-recurrent or rare SVs, we observed that genes involved by a rare SV were significantly enriched for outlier expression (z-score +/- 2) compared to a permutation background model. Rare deletions and duplications exerted their effects within 10 Kb of the gene body. Translocations and templated insertions were associated with overexpression up to 1 Mb from the gene, but had no effect when involving the gene body, consistent with a major enhancer hijacking mechanism. Finally, we sought to understand the role of recurrent and rare SVs in evolutionary dynamics, analyzing 27 patients that progressed with branching evolution. Seventy-two acquired SVs involved a hotspot region (42 driver and/or enhancer; 48 unknown), while 328 were rare. In conclusion, the SV landscape in multiple myeloma is characterized by multiple recurrently involved genes and regulatory regions. These regions account for the majority of complex SVs, indicating strong positive selection of these events. Nonetheless, the majority of SVs remain unaccounted for. Rare SVs were associated with outlier gene expression and may contribute to the tumor evolutionary trajectory of individual patients. Disclosures Papaemmanuil: Celgene: Research Funding. Landgren:Karyopharm: Membership on an entity's Board of Directors or advisory committees; Amgen: 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; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Other: IDMC; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Membership on an entity's Board of Directors or advisory committees; Theradex: Other: IDMC; Adaptive: Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3092-3092
Author(s):  
Rafail Nikolaos Tasakis ◽  
Alessandro Lagana ◽  
Violetta Leshchenko ◽  
David Melnekoff ◽  
Itai Beno ◽  
...  

RNA editing is an epitranscriptomic modification of emerging relevance to disease development and manifestations. Here we identify a novel role of the RNA editing enzyme ADAR1 in multiple myeloma (MM) progression as inducer of cognate DNA mutations. We have previously demonstrated (Lagana et al, ASH 2017) that ADAR1, which resides on human chromosome 1q21, is an RNA editor whose over-expression, either by IFN induction or through gene amplification, is associated with poor outcomes in MM. We now demonstrate robust and reproducible ADAR-mediated RNA editing in MM that increases with disease progression. At the same time, since disease progression is also correlated with the acquisition of new mutations, we asked whether ADAR1 could play the dual role of RNA editor and DNA mutator in MM, especially in the context of relapse. In fact, previous work has revealed that ADAR can exert its functions by acting on DNA/RNA hybrids in vitro (Zheng et al, Nucleic Acids Research 2017), and that DNA mutations at edited sites occur more often than at unedited sites in human and D melanogaster (Popitsch et al, BioRxiv 2017). We performed a careful bioinformatic dissection of matched pre-and post-relapse samples from 21 patients in the MMRF CoMMpass Study. Samples were profiled both with whole-exome sequencing (WES) to identify DNA mutations, and with RNAseq to identify editing instances. WES raw data was processed according to GATK Best Practices to generate alignment files, which were then processed with Samtools to identify mutations. RNAseq data was mapped using the tool GSNAP and processed using REDItools to identify editing events. Downstream analysis revealed a correlation between locations of RNA editing at diagnosis and of DNA mutation at relapse, with regions mutated matching known MM mutational hotspots in genes participating in several pathways that are relevant in MM, such as IFNa, IFNg response, IL2-STAT5 and TNF-NFkB. Finally, we demonstrated that editing at those locations is reproducible in a number of tumor cell lines, and that targeted editing of those locations could also result in the generation of mutations, similar to those we observed from patient data. Overall, we have shown that the RNA editor ADAR1, can also mutate the DNA cognate to the targeted transcript, generating specific mutational signatures at predetermined locations. We further hypothesize that this dual role of RNA editor and DNA mutator might be shared by other deaminases, and we suggest that in some contexts, DNA mutation might be the result of collateral damage on the genome by an editing enzyme whose primary job is to re-code the cognate transcript toward specific functional outcomes. Disclosures Madduri: undation Medicine: Consultancy; Celgene: Consultancy; Abbvie: Consultancy; Takeda: Consultancy. Richter:Adaptive Biotechnologies: Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Speakers Bureau; Bristol-Meyers Squibb: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees. Chari:Seattle Genetics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Research Funding; Oncoceutics: Research Funding; Novartis Pharmaceuticals: Research Funding; GlaxoSmithKline: Research Funding; Array Biopharma: Research Funding; Karyopharm: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Millennium/Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Myers Squibb: Consultancy; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Cho:Agenus: Research Funding; Genentech: Honoraria, Research Funding; BMS: Consultancy; GSK: Consultancy; Takeda: Research Funding; Celgene: Honoraria, Research Funding; The Multiple Myeloma Research Foundation: Employment. Jagannath:Celgene: Consultancy; Novartis: Consultancy; Merck: Consultancy; Medicom: Speakers Bureau; Multiple Myeloma Research Foundation: Speakers Bureau; BMS: Consultancy. Parekh:Foundation Medicine Inc.: Consultancy; Karyopharm Inc.: Research Funding; Celgene Corporation: Research Funding.


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