Engineered Oncogene Activation by Somatic Hypermutation Results in a Faithful Mouse Model of MGUS/Multiple Myeloma.

Abstract The time in cellular differentiation at which the expression of an oncogene is dysregulated is thought to determine the phenotype of the resulting neoplasia. We tested this assumption in C57BL6/J transgenic mice expressing an HA-tagged c-myc oncogene in B cells under the control of kappa light chain regulatory elements. Two transgenes were engineered that differed by only one nucleotide. The first set of mice carries a wild type HA-MYC transgene, develops pro-B cell tumors, and succumbs rapidly to pronounced lymphosplenomegaly. In the second set of mice, a point mutation in the HA-tag portion of the transgene creates a stop codon that abrogates HA-MYC translation. This stop codon was engineered to be a hotspot for somatic hypermutation. Thus sporadically, in a germinal center B cell, somatic hypermutation may revert the stop codon, allowing translation of HA-MYC. In two independently derived lines, mice spontaneously develop monoclonal gammopathies (50% incidence at 30 weeks (n=35), 80% at 40 weeks (n=35)). Serum protein electrophoresis detects M-spikes that increase in intensity over time, and 6 out of 7 cases tested so far were of IgG1 isotype. Unlike other mouse models of plasma cell neoplasia, no lymphosplenomegaly nor ascites were detected. In analogy to human multiple myeloma, that is a disease of isotype-switched and hypermutated cells homing to the bone, large populations of plasma cells were found in the bone marrow. Bone marrow (but not spleen) lysates reacted for HA and human MYC proteins by western blot and immunohistochemistry, thus indicating that reversion of the stop codon occurred. Remarkably, in two young mice, monoclonal spikes appeared 2 weeks after vaccination with NP-CGG. These spikes were sustained and the monoclonal protein was reactive to the NP antigen. Together, comparison of the two sets of mice demonstrates that activation of the same transgene at distinct B cell developmental stages results in dramatically different tumor phenotypes. In addition, and opposite to most engineered mice, we have created a system where the oncogene is turned on sporadically, as occurs in the human disease. Furthermore, we have developed a model that faithfully reproduces important clinical aspects of monoclonal gammopathy of undetermined significance (MGUS) and its progression to multiple myeloma. This model will be useful to develop immunologic and chemoterapeutic approaches.

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Myeloma Cell Associated Therapeutic Protein Discovery Using Single Cell RNA-Seq Data

Blood ◽

10.1182/blood-2020-142205 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 4-5

Author(s):

Lijun Yao ◽

Reyka G Jayasinghe ◽

Tianjiao Wang ◽

Julie O'Neal ◽

Ruiyang Liu ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

Cell Surface ◽

B Cell ◽

Tumor Cells ◽

Plasma Cell ◽

Tissue Specificity ◽

Plasma Cells ◽

Expression Data ◽

Intracellular Proteins

Multiple myeloma (MM) is a hematological cancer of the antibody-secreting plasma cells. Despite therapeutic advancements, MM remains incurable due to high incidence of drug-resistant relapse. In recent years, targeted immunotherapies, which take advantage of the immune system's cytotoxic defenses to specifically eliminate tumor cells expressing certain cell surface and intracellular proteins have shown promise in combating this and other B cell hematologic malignancies. A major limitation in the development of these therapies lies in the discovery of optimal candidate targets, which require both high expression in tumor cells as well as stringent tissue specificity. In an effort to identify potential myeloma-specific target antigens, we performed an unbiased search for genes with specific expression in plasma and/or B cells using single-cell RNA-sequencing (scRNAseq) of 53 bone marrow samples taken from 42 patients. By comparing >40K plasma cells to >97K immune cells across our cohort, we were able to identify a total of 181 plasma cell-associated genes, including 65 that encode cell-surface proteins and 116 encoding intracellular proteins. Of particular interest is that the plasma cells from each patient were shown to be transcriptionally distinct with unique sets of genes expressed defining each patient's malignant plasma cells. Using pathway enrichment analysis, we found significant overrepresentation of cellular processes related to B-Cell receptor (BCR) signaling, protein transport, and endoplasmic reticulum (ER) stress, involving genes such as DERL3, HERPUD1, PDIA4, PDIA6, RRBP1, SSR3, SSR4, TXNDC5, and UBE2J1. To note, our strategy successfully captured several of the most promising MM therapeutic targets currently under pre-clinical and clinical trials, including TNFRSF17(BCMA), SLAMF7, and SDC1 (CD138). Among these, TNFRSF17 showed very high plasma cell expression, with concomitant sharp exclusion of other immune cell types. To ascertain tissue specificity of candidate genes outside of the bone marrow, we analyzed gene and protein expression data from the Genotype-Tissue Expression (GTEx) portal and Human Protein Atlas (HPA). We found further support for several candidates (incl. TNFRSF17,SLAMF7, TNFRSF13B (TACI), and TNFRSF13C) as being both exclusively and highly expressed in lymphoid tissues. While several surface candidates were not found to be lymphocyte-restricted at the protein level, they remain relevant considerations as secondary targets for bi-specific immunotherapy approaches currently under development. To further investigate potential combinatorial targeting, we examine sample-level patterns of candidate co-expression and mutually-exclusive expression using correlation analysis. As the majority of our detected plasma cell-specific genes encode intracellular proteins, we investigated the potential utility of these epitopes as therapeutic targets via MHC presentation. Highly expressed candidates include MZB1, SEC11C, HLA-DOB, POU2AF1, and EAF2. We analyzed protein sequences using NetMHC and NETMHCII to predict high-affinity peptides for common class-I and class-II HLA alleles. To correlate MHC allelic preference with candidate expression in our cohort, we performed HLA-typing for 29 samples using Optitype. To support our scRNAseq-driven findings, we cross-referenced gene expression data with 907 bulk RNA-sequencing samples, including 15 from internal studies and 892 from the Multiple Myeloma Research Foundation (MMRF), as well as bulk global proteomics data from 4 MM cell lines (TIB.U266, RPMI8226, OPM2, MM1ST) and 4 patients. We see consistent trends across both cohorts, with high positive correlation (Pearson R ranging between 0.60 and 0.99) for a majority of genes when comparing scRNA and bulk RNA expression in the same samples. Our experimental design and analysis strategies enabled the efficient discovery of myeloma-associated therapeutic target candidates. In conclusion, this study identified a set of promising myeloma CAR-T targets, providing novel treatment options for myeloma patients. Disclosures Goldsmith: Wugen Inc.: Consultancy. DiPersio:Magenta Therapeutics: Membership on an entity's Board of Directors or advisory committees.

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Clonal Analysis of IgM Cells in Multiple Myeloma Patients Suggests the Co-Existence of Normal and Malignant Arms of the Myeloma Clone.

Blood ◽

10.1182/blood.v104.11.1415.1415 ◽

2004 ◽

Vol 104 (11) ◽

pp. 1415-1415

Author(s):

Brian J. Taylor ◽

Ming Ye ◽

Erin R. Strachan ◽

Tara M. Tiffinger ◽

Andrew R. Belch ◽

...

Keyword(s):

Multiple Myeloma ◽

B Cell ◽

Plasma Cells ◽

Somatic Hypermutation ◽

Immunomagnetic Separation ◽

B Cell Differentiation ◽

Reading Frame ◽

A Minor ◽

Pcr Targeting ◽

Insight Into

Abstract Analysis of immunoglobulin V genes, which undergo stepwise changes during B cell differentiation such as VDJ rearrangement, somatic hypermutation, and class switch recombination, provides insight into the point of transformation of B cell tumors. In Multiple Myeloma (MM), clonotypic VDJ sequences of malignant plasma cells are mutated, homogeneous, and associated with post-switch constant regions (either IgG or IgA, called the clinical isotype), suggesting the malignant arm of the MM clone arises from transformation events in the late stages of the germinal centre reaction. By contrast, the existence of clonotypic VDJ associated with pre-switch IgM is well established, and we have shown persistent clonotypic IgM is associated with advanced disease at diagnosis and poor survival in MM. Whether clonotypic IgM cells represent a malignant progenitor or a non-malignant population that parallels disease severity is unclear. To address these possibilities, we focused our analysis of clonotypic VDJ mutation profiles on IgM+ cells sorted by immunomagnetic separation from MM patient peripheral blood cells (PBMC). IgM clonotypic transcripts were amplified by hemi-nested RT-PCR targeting the CDR2-C mu constant region in IgM+ cells from 4/7 patients. These products were cloned, and 122, 28, 27, and 25 IgM clonotypic colonies were identified by specific CDR2/CDR3 PCR for patients 1–4 respectively. Each of these clones was sequenced, and mutations were identified by comparison with the closest germline V gene and tumor derived plasma cell VDJ sequences. An average mutation frequency of 0.005, significantly greater than the Taq error rate, was obtained for the 250–280 bp fragment downstream of CDR2, including the D-J-C mu region. Typically, MM clones were observed with 1–2 mutations in this region, many localizing to the D-J-C mu region. Small deletions that preserve reading frame were also observed in the D region of single clones of patients 1 and 4 respectively. The detection of intraclonal heterogeneity amongst clonotypic IgM cells may reflect a normal arm of the myeloma clone that co-exists with the post-switch malignant arm. In previous work examining bulk PBMC populations we had detected diversified clonotypic cells in the non-clinical isotype compartment of one patient, but, in accordance with studies performed by several other groups, were unable to detect diversified pre-switch counterparts. In this work we have focused on IgM+ MM B cells, a compartment of the MM clone that may remain driven by antigenic selection and undergo persistent clonal expansion. Our analysis gives insight into the nature of this proposed normal arm of the myeloma clone, revealing two coexisting subsets of pre-switch clonotypic IgM cells: a major set exhibiting homogeneity, identity with post-switch tumor VDJ, and questionable transformation status, and a minor clonally heterogeneous set which may represent the pre-malignant clone from which myeloma arose.

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CS1: A Potential New Therapeutic Target for the Treatment of Multiple Myeloma.

Blood ◽

10.1182/blood.v108.11.3457.3457 ◽

2006 ◽

Vol 108 (11) ◽

pp. 3457-3457 ◽

Cited By ~ 3

Author(s):

Eric D. Hsi ◽

Roxanne Steinle ◽

Balaji Balasa ◽

Aparna Draksharapu ◽

Benny Shum ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

Flow Cytometry ◽

B Cell ◽

Mononuclear Cells ◽

Plasma Cells ◽

Target Cells ◽

Dependent Manner ◽

Myeloma Cells ◽

Effector Cells

Abstract Background: To identify genes upregulated in human memory B and plasma cells, naïve B cell cDNA was subtracted from plasma cell and memory B cell cDNA. One gene that was highly expressed in plasma cells encodes CS1 (CD2 subset 1, CRACC, SLAMF7), a cell surface glycoprotein of the CD2 family. CS1 was originally identified as a natural killer (NK) cell marker. Monoclonal antibodies (mAbs) specific for CS1 were used to validate CS1 as a potential target for the treatment of multiple myeloma (MM). Methods: Anti-CS1 mAbs were generated by immunizing mice with a protein comprising of the extracellular domain of CS1. Two clones, MuLuc63 and MuLuc90, were selected to characterize CS1 protein expression in normal and diseased tissues and blood. Fresh frozen tissue analysis was performed by immunohistochemistry (IHC). Blood and bone marrow analysis was performed using flow cytometry with directly conjugated antibodies. HuLuc63, a novel humanized anti-CS1 mAb (derived from MuLuc63) was used for functional characterization in non-isotopic LDH-based antibody-dependent cellular cytotoxicity (ADCC) assays. Results: IHC analysis showed that anti-CS1 staining occurred only on mononuclear cells within tissues. The majority of the mononuclear cells were identified as tissue plasma cells by co-staining with anti-CD138 antibodies. No anti-CS1 staining was detected on the epithelia, smooth muscle cells or vessels of any normal tissues tested. Strong anti-CS1 staining was also observed on myeloma cells in 9 of 9 plasmacytomas tested. Flow cytometry analysis of whole blood from both normal healthy donors and MM patients showed specific anti-CS1 staining in a subset of leukocytes, consisting primarily of CD3−CD(16+56)+ NK cells, CD3+CD(16+56)+ NKT cells, and CD3+CD8+ T cells. Flow cytometry of MM bone marrow showed a similar leukocyte subset staining pattern, except that strong staining was also observed on the majority of CD138+CD45−/dim to + myeloma cells. No anti-CS1 binding was detected to hematopoietic CD34+CD45+ stem cells. To test if antibodies towards CS1 may have anti-tumor cell activity in vitro, ADCC studies using effector cells (peripheral blood mononuclear cells) from 23 MM patients and L363 MM target cells were performed. The results showed that HuLuc63, a humanized form of MuLuc63, induced significant ADCC in a dose dependent manner. Conclusions: Our study identifies CS1 as an antigen that is uniformly expressed on normal and neoplastic plasma cells at high levels. The novel humanized anti-CS1 mAb, HuLuc63, exhibits significant ADCC using MM patient effector cells. These results demonstrate that HuLuc63 could be a potential new treatment for multiple myeloma. HuLuc63 will be entering a phase I clinical study for multiple myeloma.

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Double Hematological Malignancy: An Unusual Presentation in Three Cases

Blood ◽

10.1182/blood.v112.11.5294.5294 ◽

2008 ◽

Vol 112 (11) ◽

pp. 5294-5294

Author(s):

Rami Y. Haddad ◽

Navneet Attri ◽

Yaser Kawar

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

Chronic Lymphocytic Leukemia ◽

Partial Response ◽

B Cell ◽

Hematological Malignancies ◽

Plasma Cells ◽

Hematological Malignancy ◽

Lymphocytic Leukemia ◽

Refractory Anemia

Abstract The occurrence of more than one hematological malignancy in the same patient is an unusual pathologic condition and may pose a difficult challenge during decision to start various chemotherapy regimens. Cases of solid tumors of lung and gastrointestinal tract have been noted secondary to treatment of hematological malignancies but the occurrence of two hematological malignancies concomitantly is a rare presentation. We describe three cases of coexistent hematological malignancies at our institution. First case describes a 77 yo male with synchronously occurring B cell Non Hodgkin Lymphoma: marginal zone lymphoma (main bone marrow population); Chronic Lymphocytic leukemia (Fluorescent-in–situ hybridization test positive for trisomy 12) and a Monoclonal Beta, elevated IgM, elevated B2. BM evaluation revealed involvement by both processes. The patient has been started on Rituximab recently. The second case is an 85 yo male with findings with peripheral blood flow cytometry consistent with chronic lymphocytic leukemia of B-cell immunophenotype and lymph node biopsy consistent with Follicular Lymphoma. He was found to be BCL2 + on BM and had a normal Karyotype: 46, XY. He was treated with Rituximab ×8 cycles. A follow up PET scan showed partial response. Our third case was an 83 yo man with simultaneous presentation of myelodysplastic syndrome (MDS) and multiple myeloma (MM). This patient had MDS (Refractory anemia with Ring sideroblasts RARS type) and smoldering Multiple myeloma (monoclonal plasma cells 10–15%) bone marrow infiltration which over a course of 3 years transformed into full blown Multiple Myeloma with bone marrow revealing 30–40% plasma cells and osteolytic lesions on skeletal survey. Cytogenetic were normal. He was treated with Lenalidomide (after failure of ESA) and became transfusion in dependent for one year (Hgb rose from baseline of 6–7 to 13 g/dL), after progression to active multiple myeloma he was treated with Thalidomide and Dexamthesone. He achieved a partial response on SPEP. Subsequently he was treated for MDS progression with Azacytidine for 5 cycles with minor hematological benefit (transfusion was less frequently), he recently succumbed to his disease, he was transfusion dependent and became acutely ill after an acute episode of diverticulitis. Patients with MM, MDS have been reported after chemotherapy but few cases documenting the coexistence of MDS and MM at diagnosis have been reported in the literature. Conclusion: In this report, we describe a three cases of double hematological clonal processes or malignancy, all diagnosed at same time, without preceding hematological disorder or chemotherapy, and all required treatment.

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Evidence for a bone marrow B cell transcribing malignant plasma cell VDJ joined to C mu sequence in immunoglobulin (IgG)- and IgA-secreting multiple myelomas.

Journal of Experimental Medicine ◽

10.1084/jem.178.3.1091 ◽

1993 ◽

Vol 178 (3) ◽

pp. 1091-1096 ◽

Cited By ~ 80

Author(s):

P Corradini ◽

M Boccadoro ◽

C Voena ◽

A Pileri

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

B Cells ◽

B Cell ◽

B Lymphocytes ◽

Plasma Cell ◽

Plasma Cells ◽

Bone Marrow Cells ◽

Indirect Evidence ◽

Specific Marker

Multiple myeloma is a B cell malignancy characterized by the expansion of plasma cells producing monoclonal immunoglobulins (Ig). It has been regarded as a tumor arising at the B, pre-B lymphocyte, or even stem cell level. Precursor cells are presumed to proliferate and differentiate giving rise to the plasma cell clonal expansion. Antigenic features and specific Ig gene rearrangement shared by B lymphocytes and myeloma cells have supported this hypothesis. However, the existence of such a precursor is based upon indirect evidence and is still an open question. During differentiation, B cells rearrange variable (V) regions of Ig heavy chain genes, providing a specific marker of clonality. Using an anchor polymerase chain reaction assay, these rearranged regions from five patients with multiple myeloma were cloned and sequenced. The switch of the Ig constant (C) region was used to define the B cell differentiation stage: V regions are linked to C mu genes in pre-B and B lymphocytes (pre-switch B cells), but to C gamma or C alpha in post-switch B lymphocytes and plasma cells (post-switch B cells). Analysis of bone marrow cells at diagnosis revealed the presence of pre-switch B cells bearing plasma cell V regions still joined to the C mu gene. These cells were not identified in peripheral blood, where tumor post-switch B cells were detected. These pre-switch B cells may be regarded as potential myeloma cell precursors.

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A novel membrane antigen selectively expressed on terminally differentiated human B cells

Blood ◽

10.1182/blood.v84.6.1922.1922 ◽

1994 ◽

Vol 84 (6) ◽

pp. 1922-1930 ◽

Cited By ~ 142

Author(s):

T Goto ◽

SJ Kennel ◽

M Abe ◽

M Takishita ◽

M Kosaka ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

B Cells ◽

B Cell ◽

Plasma Cell ◽

Peripheral Blood ◽

Plasma Cells ◽

Affinity Constant ◽

Target Antigen ◽

Specific Marker

Abstract A monoclonal antibody (MoAb) that defines a novel terminal B-cell- restricted antigen, termed HM1.24, was developed against a human plasma cell line. The MoAb, designated anti-HM1.24, reacted with five different human myeloma cell lines, as well as with monoclonal neoplastic plasma cells obtained from the bone marrow or peripheral blood of patients with multiple myeloma or Waldenstrom's macroglobulinemia. The HM1.24 antigen was also expressed by mature Ig- secreting B cells (plasma cells and lymphoplasmacytoid cells) but not by other cells contained in the peripheral blood, bone marrow, liver, spleen, kidney, or heart of normal individuals or patients with non- plasma-cell-related malignancies. The anti-HM1.24 MoAb bound to human myeloma RPMI 8226 cells with an affinity constant of 9.2 x 10(8) M-1, indicating approximately 84,000 sites/cell. By immunoprecipitation assay under reducing conditions, this MoAb identified a membrane glycoprotein that had a molecular weight of 29 to 33 kD. Our studies indicate that the HM1.24-related protein represents a specific marker of late-stage B-cell maturation and potentially serves as a target antigen for the immunotherapy of multiple myeloma and related plasma cell dyscrasias.

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A novel membrane antigen selectively expressed on terminally differentiated human B cells

Blood ◽

10.1182/blood.v84.6.1922.bloodjournal8461922 ◽

1994 ◽

Vol 84 (6) ◽

pp. 1922-1930 ◽

Cited By ~ 1

Author(s):

T Goto ◽

SJ Kennel ◽

M Abe ◽

M Takishita ◽

M Kosaka ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

B Cells ◽

B Cell ◽

Plasma Cell ◽

Peripheral Blood ◽

Plasma Cells ◽

Affinity Constant ◽

Target Antigen ◽

Specific Marker

A monoclonal antibody (MoAb) that defines a novel terminal B-cell- restricted antigen, termed HM1.24, was developed against a human plasma cell line. The MoAb, designated anti-HM1.24, reacted with five different human myeloma cell lines, as well as with monoclonal neoplastic plasma cells obtained from the bone marrow or peripheral blood of patients with multiple myeloma or Waldenstrom's macroglobulinemia. The HM1.24 antigen was also expressed by mature Ig- secreting B cells (plasma cells and lymphoplasmacytoid cells) but not by other cells contained in the peripheral blood, bone marrow, liver, spleen, kidney, or heart of normal individuals or patients with non- plasma-cell-related malignancies. The anti-HM1.24 MoAb bound to human myeloma RPMI 8226 cells with an affinity constant of 9.2 x 10(8) M-1, indicating approximately 84,000 sites/cell. By immunoprecipitation assay under reducing conditions, this MoAb identified a membrane glycoprotein that had a molecular weight of 29 to 33 kD. Our studies indicate that the HM1.24-related protein represents a specific marker of late-stage B-cell maturation and potentially serves as a target antigen for the immunotherapy of multiple myeloma and related plasma cell dyscrasias.

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Mieloma multipel: aspek patogenesis molekuler

Jurnal Penyakit Dalam Udayana ◽

10.36216/jpd.v3i1.70 ◽

2019 ◽

Vol 3 (1) ◽

pp. 1-7

Author(s):

Made Bakta

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

Germinal Center ◽

B Lymphocyte ◽

Plasma Cells ◽

Somatic Hypermutation ◽

P53 Mutation ◽

Bone Lesions ◽

Genetic Changes ◽

Clonal Proliferation

Multiple myeloma (MM) is a neoplastic plasma disorder that is characterized by clonal proliferation of malignant plasma cells in the bone marrow, monoclonal protein in the blood or urine and associated organ dysfunction. It is preceded by a premalignant tumor which is share genetic abnormalities, monoclonal gammopathy of undetermined significance (MGUS). Although remarkable progress has been achieved, but pathogenesis of MM is still very complex. Multiple myeloma appears to arise from the malignant transformation of germinal-center B-lymphocyte. The first oncogenic events in MM appear to occur in the germinal center due to error in isotype class switching and somatic hypermutation. MM is divided into two distinct genetic subtypes: (1) hyperdiploid myeloma is characterized by multiple trisomies of chromosome 3, 5, 7, 9, 11, 15, 19 and 21; (2) non-hyperdiploid in contrast is characterized by recurrence translocations t(4;14), t(14;16), t (14;20); t(6;14) and t(11;14). A unifying event in the pathogenesis of MM is the dysregulated expression of cyclin D gene. Genetic aberrations occur in MM and also in premalignant state (MGUS), suggesting that genetic mutations alone are necessary, but not sufficient for myeloma transformation. A “ random second hit model” was proposed. Hypothetical second hits are: additional genetic changes ( RAS mutation, p16 methylation, p53 mutation), proliferation due to cell cycle dysregulation, evasion of programmed cell death and changes in bone marrow microenvironment. A complex interaction with the BM microenvironment , characterized by activation of osteoclast and supression of osteoblast , leads to lytic bone lesions.

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Small RNA Next Generation Sequencing (NGS) of CD138+ Plasma Cells from Multiple Myeloma Patients and Comparison to the 70-Gene mRNA-Based Prognostic Risk Score

Blood ◽

10.1182/blood.v128.22.2089.2089 ◽

2016 ◽

Vol 128 (22) ◽

pp. 2089-2089

Author(s):

Ryan van Laar ◽

Kenton Leigh ◽

Aga Zielinski ◽

Nathan Brown ◽

Richard A Bender

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

Cell Line ◽

Risk Score ◽

Small Rna ◽

Plasma Cells ◽

Low Risk ◽

Myc Oncogene ◽

Number Of Patients ◽

Gene Mrna

Abstract Background: Small-RNAs (including microRNAs) are a novel class of molecules with functions that include the regulation of coding genes as well as development, proliferation, apoptosis and differentiation of myeloma cells. The presence of these genes has been detected inside cells and also in the extracellular environment, suggesting they may be useful for risk stratification and treatment monitoring. We sought to explore the small-RNA profiles of bone marrow specimens submitted for MyPRS analysis and identify candidate molecules associated with a patient's 70-gene (mRNA) prognostic risk score. Method and Results: 32 bone marrow aspirate samples from patients with multiple myeloma, 3 whole-blood control samples and the MM cell line NCI-H929 were included in the present study. Plasma cells were isolated from the bone marrow aspirates as per standard MyPRS protocols. Total RNA was then extracted using the miRNeasy Mini Kit protocol (Qiagen, Canada). All miRNA libraries were prepared using the Illumina TruSeq Small RNA protocol following the manufacturer's instructions with 11-15 cycles of PCR amplification. Individual libraries were prepared using a unique index primer to allow for pooling of multiple samples. After amplification, Novex TBE PAGE gel electrophoresis was used to select for fragments sized 145- 160 nt, corresponding to mature miRNA's and other small RNA molecules. Libraries were validated and quantified using an Agilent 2100 Bioanalyzer High Sensitivity DNA chip, sequenced on an Illumina NextSeq 500 and analyzed using Illumina BaseSpace Onsite. After adapter trimming, an average of 3.7, 17.7 and 0.5 million reads were generated from the multiple myeloma, normal blood and NCI-H929 cell line libraries, respectively. When comparing the MM vs. control data, 757/6041 total miRNA's passed a low-count filter and 535 of these were found to be differentially expressed. The top 10 miRNA families with the largest difference between sample types according to DESEq2 were mir-1285, let-7, mir-1248, mir-1303, mir-1260b, mir-1301, mir-10, mir-128, mir-129 and mir-130. Within the MM sample group, 620 individual miRNAs were reliably detected and compared between GEP70 high and low risk disease, with 14 passing a differential expression filter. Hierarchal clustering of patients using all 620 genes did not separate patients into high and low risk groups and only 2/411 miRNA families (mir-130 and mir-17) were found to differ between these classes. Serum levels of miR-130a in MM patients have been shown to be associated with extramedullary disease and miR-17 is thought to regulate the Myc oncogene. Conclusion: In this study we identified a number of novel microRNAs with patterns of expression in patient bone marrow aspirates associated with the extensively validated 70-gene risk score available commercially as 'MyPRS'. Two particular miRNA's were identified that appear to be associated with high risk behavior, one of which correlates with the Myc oncogene whose relationship to clinically aggressive MM is well described. Further work is planned to expand the number of patients in the study and to investigate whether these microRNA's are present in the extracellular bone marrow environment and peripheral fluids. Disclosures van Laar: Signal Genetics, Inc.: Employment. Leigh:Signal Genetics, Inc.: Employment. Zielinski:Signal Genetics, Inc.: Employment. Brown:Signal Genetics, Inc.: Employment. Bender:Signal Genetics, Inc.: Employment.

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Expression of shared idiotypes by paraproteins from patients with multiple myeloma and monoclonal gammopathy of undetermined significance

Blood ◽

10.1182/blood.v75.11.2107.bloodjournal75112107 ◽

1990 ◽

Vol 75 (11) ◽

pp. 2107-2111

Author(s):

JR Berenson ◽

A Lichtenstein ◽

S Hart ◽

D Palomares ◽

RA Miller

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

B Cell ◽

Monoclonal Gammopathy ◽

Plasma Cells ◽

Lymphocytic Leukemia ◽

B Cell Lymphomas ◽

Similar Frequency ◽

Murine Monoclonal Antibodies ◽

Undetermined Significance

Twenty-nine murine monoclonal antibodies have been produced that react with shared idiotypes expressed by B-cell lymphomas and leukemias. We tested this panel of antibodies for reactivity with the paraproteins from 32 patients with multiple myeloma and 10 patients with monoclonal gammopathy of undetermined significance (MGUS). Thirteen of 42 paraproteins reacted with at least one antibody in this panel of anti- idiotypic antibodies. Six different anti-idiotypes demonstrated reactivity with the paraproteins. A similar frequency of reactivity was found for both myeloma and MGUS proteins. One antibody, S30–47, reacted with 6 of 32 (19%) of the paraproteins from patients with multiple myeloma, whereas this anti-idiotype only bound to 3% of non-Hodgkin's B- cell lymphomas and no cases of chronic lymphocytic leukemia. This anti- idiotype reacted with both components of a biphenotypic paraprotein (IgG kappa and IgG lambda) in one patient. In each of nine patients tested, plasma cells isolated from bone marrow were shown to be reactive with the same anti-idiotype we found to react with the paraprotein. Antishared idiotype antibodies may provide useful reagents for studies of patients with monoclonal gammopathies.

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