A Novel Role For Histone Deacetylase 11 (HDAC11) In Plasma Cell Differentation and Survival

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1907-1907
Author(s):  
Eva Sahakian ◽  
Jason B. Brayer ◽  
John Powers ◽  
Mark Meads ◽  
Allison Distler ◽  
...  

Abstract The role of HDACs in cellular biology, initially limited to their effects upon histones, is now appreciated to encompass more complex regulatory functions that are dependent on their tissue expression, cellular compartment distribution, and the stage of cellular differentiation. Recently, our group has demonstrated that the newest member of the HDAC family of enzymes, HDAC11, is an important regulator of IL-10 gene expression in myeloid cells (Villagra A Nat Immunol. 2009). The role of this specific HDAC in B-cell development and differentiation is however unknown. To answer this question, we have utilized a HDAC11 promoter-driven eGFP reporter transgenic mice (TgHDAC11-eGFP) which allows the monitoring of the dynamic changes in HDAC11 gene expression/promoter activity in B-cells at different maturation stages (Heinz, N Nat. Rev. Neuroscience 2001). First, common lymphoid progenitors are devoid of HDAC11 transcriptional activation as indicated by eGFP expression. In the bone marrow, expression of eGFP moderately increases in Pro-B-cells and transitions to the Pre- and Immature B-cells respectively. Expression of eGFP doubles in the B-1 stage of differentiation in the periphery. Of note, examination of both the bone marrow and peripheral blood plasma cell compartment demonstrated increased expression of eGFP/HDAC11 mRNA at the steady-state. These results were confirmed in plasma cells isolated from normal human subjects in which HDAC11 mRNA expression was demonstrated. Strikingly, analysis of primary human multiple myeloma cells demonstrated a significantly higher HDAC11 mRNA expression in malignant cells as compared to normal plasma cells. Similar results were observed in 4/5 myeloma cell lines suggesting that perhaps HDAC11 expression might provide survival advantage to malignant plasma cells. Support to this hypothesis was further provided by studies in HDAC11KO mice in which we observed a 50% decrease in plasma cells in both the bone marrow and peripheral blood plasma cell compartments relative to wild-type mice. Taken together, we have unveiled a previously unknown role for HDAC11 in plasma cell differentiation and survival. The additional demonstration that HDAC11 is overexpressed in primary human myeloma cells provide the framework for specifically targeting this HDAC in multiple myeloma. Disclosures: Alsina: Millennium: Membership on an entity’s Board of Directors or advisory committees, Research Funding. Baz:Celgene Corporation: Research Funding; Millenium: Research Funding; Bristol Myers Squibb: Research Funding; Novartis: Research Funding; Karyopharm: Research Funding; Sanofi: Research Funding.

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2424-2424
Author(s):  
Yang Liu ◽  
Yong Zhang ◽  
Phong Quang ◽  
Hai T Ngo ◽  
Feda Azab ◽  
...  

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


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2917-2917
Author(s):  
Jennifer Li ◽  
Andrew Leu ◽  
Mingjie Li ◽  
Ethan D Hobel ◽  
Kevin Delijani ◽  
...  

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.


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 311-311 ◽  
Author(s):  
Laurie Herviou ◽  
Alboukadel Kassambara ◽  
Stephanie Boireau ◽  
Nicolas Robert ◽  
Guilhem Requirand ◽  
...  

Abstract Multiple Myeloma is a B cell neoplasia characterized by the accumulation of clonal plasma cells within the bone marrow.Epigenetics is characterized by a wide range of changes that are reversible and orchestrate gene expression. Recent studies have shown that epigenetic modifications play a role in multiple myeloma (MM) by silencing various cancer-related genes. We investigated the epigenetic genes differentially expressed between normal bone marrow plasma cells (BMPC ; N=5) and MM plasma cells from patients (N=206). Using SAM (Significance Analysis of Microarrays) analysis, only 12 genes significantly differentially expressed between BMPC and MM cells (ratio > 2 and FDR (false discovery rate) < 5%) were identified, including the EZH2 histone methyltransferase. EZH2, the enzymatic subunit of Polycomb Repressive Complex 2, is a histone methyltransferases able to repress gene expression by catalyzing H3K27me3 histone mark. EZH2 overexpression has been associated with numerous hematological malignancies, including MM. We thus studied EZH2 role in MM physiopathology and drug resistance. EZH2 expression was analyzed in normal bone marrow plasma cells (BMPCs; N=5), primary myeloma cells from newly diagnosed patients (MMCs; N=206) and human myeloma cell lines (HMCLs; N=40) using Affymetrix microarrays. EZH2 gene is significantly overexpressed in MMCs of patients (median 574, range 105 - 4562) compared to normal BMPCs (median = 432; range: 314 - 563) (P < 0.01). The expression is even higher in HMCLs (median 4481, range 581 - 8455) compared to primary MMCs or BMPCs (P < 0.001). High EZH2 expression is associated with a poor prognosis in 3 independent cohorts of newly diagnosed patients (Heidelberg-Montpellier cohort - N=206, UAMS-TT2 cohort - N=345 and UAMS-TT3 cohort - N =158). Furthermore, GSEA analysis of patients with high EZH2 expression highlighted a significant enrichment of genes involved in cell cycle, downregulated in mature plasma cells vs plasmablasts, and EZH2 targets. Specific EZH2 inhibition by EPZ-6438 EZH2 inhibitor induced a significant decrease of global H3K27me3 in all the HMCLs tested (P < 0.01) and inhibited MM cell growth in 5 out of the 6 HMCLs tested. The inhibitory effect of EZH2 inhibitor on MM cell growth appeared at day 6 suggesting that it is mediated by epigenetic reprogramming. To confirm that EZH2 is also required for the survival of primary MMCs from patients, primary MM cells (n = 17 patients) co-cultured with their bone marrow microenvironment and recombinant IL-6 were treated with EPZ-6438. As identified in HMCLs, EZH2 inhibition significantly reduced the median number of viable myeloma cells by 35% (P = 0.004) from a subset of patients (n=9) while the other group (n=8) was resistant. Of interest, EPZ-6438 induced a significant global H3K27me3 decrease in both groups of patient. RNA sequencing of 6 HMCLs treated with EPZ-6438 combined with H3K27me3 ChIP analyses allowed us to create an EZ GEP-based score able to predict HMCLs and primary MM cells sensitivity to EZH2 inhibitors. We also observed a synergy between EPZ-6438 and Lenalidomide, a conventional drug used for MM treatment. More interestingly, pretreatment of myeloma cells with EPZ-6438 significantly re-sensitize drug-resistant MM cells to Lenalidomide. Investigating the effect of EPZ-6438/Lenalidomide combination in MMC, we identified that IKZF1, IRF4 and MYC protein levels were significantly more inhibited by the combination treatment (65.5%, 63.9% and 14.8% respectively) compared with Lenalidomide (51.5%, 43% and 2.2%) or EPZ-6438 (45.2%, 38.7% and 6.2%) alone. Clinical trials are ongoing with EZH2 inhibitors in lymphoma and could be promising for a subgroup of MM patients in combination with IMiDs. Furthermore, the EZ score enables identification of MM patients with an adverse prognosis and who could benefit from treatment with EZH2 inhibitors. Disclosures Goldschmidt: Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Onyx: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Research Funding; Millennium: Membership on an entity's Board of Directors or advisory committees, Research Funding; Chugai: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Janssen: 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; Takeda: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees. Hose:EngMab: Research Funding; Takeda: Other: Travel grant; Sanofi: Research Funding.


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3405-3405
Author(s):  
Dirk Hose ◽  
John DeVos ◽  
Christiane Heiß ◽  
Jean-Francois Rossi ◽  
Angela Rösen-Wolff ◽  
...  

Abstract BACKGROUND. Angiogenesis is a hallmark of active multiple myeloma. However, two etiologic hypotheses have been proposed: an angiogenic switch (i.e. differential or de novo expression of pro/antiangiogenic genes in MM), and, alternatively an effect of increased plasma cell number. AIM of this study was to investigate the angiogenic signature of multiple myeloma cells (MMC), normal bone marrow plasma cells (BMPC), the bone marrow microenvironment (BMME) and cellular subfractions therein. PATIENTS AND METHODS. 128 newly diagnosed MM-patients (65 training (TG) / 63 independent validation group (VG)) and 14 normal donors (ND) were included. Bone marrow aspirates were CD138-purified by activated magnetic cell sorting. Whole bone marrow (n=49) and FACSAria sorted subfractions thereof (n=5) were investigated. RNA was in-vitro transcribed and hybridised to Affymetrix HG U133 A+B GeneChip (TG) and HG U133 2.0 plus arrays (VG). Expression data were gcrma-normalised and the empirical Bayes algorithm used. p-Values were adjusted using the Benjamini-Hochberg method (Bioconductor). iFISH was performed on purified MM-cells using probesets for chromosomes 1q21, 9q34, 11q23, 11q13, 13q14, 15q22, 17p13, 19q13, 22q11 and the translocations t(4;14) and t(11;14). HGF expression was verified by real time RT-PCR and western blotting. Based on Medline review, we established a list of 89 pro- and 56 antiangiogenic genes and investigated their expression according to the stage of disease: BMPC vs. MGUS, SD stage I (asymptomatic myeloma) vs. SD stage II/III (symptomatic myeloma requiring therapy). RESULTS. BMPC express pro- (e.g. VEGFA) and antiangiogenic genes (e.g. TIMP2). Only one pro-angiogenic gene (hepatocyte growth factor, HGF) is significantly overexpressed in MMC compared to BMPC. HGF has previously been linked with myeloma progression and induction of angiogenesis. Six antiangiogenic genes (TIMP2, SERPINF1, COL18A1, PF4, THBS1, CXCL14) are downregulated in MMC compared with BMPC. Compared to healthy donors, the BMME of MM shows a significant downregulation of PLAU (urokinase, antiangiogenic) and upregulation of TNF(proangiogenic). CONCLUSION. Upregulation of HGF-expression, downregulation of TIMP2, SERPINF1, COLA18A1, PF4, THBS1 and CXCL14 expression in MMC as well as downregulation of PLAU and upregulation of TNFα in the BMME seem to indicate an “angiogenic switch”. However, given the relatively low number of differentially expressed genes (7/145) and the expression of angiogenic genes by BMPC, an effect caused by an increasing number of plasma cells might be evenly important.


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 ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2735-2735
Author(s):  
Jerome Moreaux ◽  
Dirk Hose ◽  
Thierry Rème ◽  
Philippe Moine ◽  
Karène Mahtouk ◽  
...  

Abstract Multiple myeloma (MM) is a fatal hematologic malignancy associated with clonal expansion of malignant plasma cells within the bone marrow and the development of a destructive osteolytic bone disease. The principal cellular mechanisms involved in the development of myeloma bone disease are an increase in osteoclastic bone resorption, and a reduction in bone formation. Myeloma cells (MMC) are found in close association with sites of active bone resorption, and the interactions between myeloma cells and other cells within the specialized bone marrow microenvironment are essential, both for tumor growth and the development of myeloma bone disease. In order to investigate the gene expression profile (GEP) of osteoclastic cells, we compare GEP of osteoclastic cells (7 samples) with normal B cells (7 samples), normal bone marrow plasma cells (7 samples), bone marrow stromal cells (5 samples), bone marrow CD3 cells (5 samples), CD14 cells (7 samples), CD15 cells (7 samples), CD34 cells (7 samples) and primary MMC (123 samples). Using SAM analysis, a set of 552 genes was overexpressed in osteoclasts compared to others cell subpopulations with a FDR ≤ 1% and a ratio ≥ 2. Osteoclasts specifically overexpressed genes coding for chemokines (CCL2, CCL7, CCL8, CCL13, CCL18, CXCL5 and CCL23) and MMC growth factors (IGF-1, APRIL and IL-10). Anti- IGF-1 receptor and TACI-Fc inhibit MMC growth induced by osteoclasts. Among the chemokines overexpressed by osteoclasts, the majority of them have a common receptor: CCR2 expressed by MMC. Anti-CCR2 MoAb inhibits migration of the CCR2+ HMCL in response to osteoclasts. Expression data of purified MMC were analyzed by supervised clustering of group with higher (CCR2high) versus lower (CCR2low) CCR2 expression level. Patients in the CCR2high group are characterized by a higher bone disease. A set of 176 genes was differentially expressed between CCR2high and CCR2low MMC. CCR2high displayed a gene signature linked to the dependency of MMC on the interactions with the BM osteoclastic subpopulation and the osteoclastic bone resorption. Taken together, our findings suggest addition of chemokine antagonists to current treatment regimens for MM should result in better therapeutic responses because of the loss of both the protective effect of the bone marrow environment on the MMC and the osteoclastic cells activity.


Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 327-327
Author(s):  
Takashi Asai ◽  
Silvia Menendez ◽  
Delphine Ndiaye-Lobry ◽  
Anthony R Deblasio ◽  
Kazunori Murata ◽  
...  

Abstract Abstract 327 Multiple myeloma is characterized by the progressive expansion of monoclonal plasma cells in the bone marrow, which leads to the production of serum and/or urine monoclonal proteins and systemic complications including lytic bone lesions, renal abnormalities hypercalcemia, and infections. Although the treatment of multiple myeloma has vastly improved, multiple myeloma remains a generally incurable disease. Transgenic mouse models have been generated that develop plasma cell accumulations or myeloma, however these models are quite imperfect in mimicking the human disease. Quite serendipitously, we have generated a multi-stage, progressive, and transplantable mouse model of multiple myeloma, crossing a genetically modified mouse with aberrant class switch recombination with another modified mouse that has elevated DNA damage response signaling. We have reported that cells expressing the hypermorphic Rad50s allele show constitutive ATM activation, leading to cancer predisposition and aggressive hematopoietic failure in Rad50s/s mice. While deficiency of the transcription factor Mef/Elf4, which regulates the quiescence of hematopoietic stem/progenitor cells, can mitigate hematopoietic failure observed in Rad50s/s mice, we found that 70% of Mef−/−Rad50s/s mice more than 200 days old died from multiple myeloma, plasmacytoma, or plasma cell leukemia, confirmed by pathology, immunohistochemistry, flowcytometry (CD138/B220 profiles), and PCR analysis for VDJ recombination. Prior to the onset of the plasma cell neoplasms, the Mef−/−Rad50s/s mice show abnormal plasma cell accumulation in the peripheral blood and bone marrow, which worsens with age. As the mice age, they also develop progressive increases in g-globulin levels and decreases in serum albumin levels. Monoclonal protein peaks were frequently observed in the serum of mice older than 200 days, and in step with the progressive nature of these manifestations, anemia and lower bone mineral density becomes apparent as the mice further age. Overall, the median survival of the Mef−/−Rad50s/s mice is approximately 470 days. The plasma cell neoplasms derived from Mef−/−Rad50s/s mice can be transplanted into recipient mice and the onset of the transplanted disease is markedly accelerated, to approximately 4 weeks post transplantation. Thus, the transplanted neoplastic Mef−/−Rad50s/s plasma cells appear to be more aggressive than the original ones. Taken together, our findings suggest that the Mef−/−Rad50s/s animal model can recapitulate the spectrum and pace of human plasma cell neoplasms, including the progression from monoclonal gammopathy to multiple myeloma. Class switch recombination is facilitated in Mef−/−Rad50s/s B cells in vitro, compared with control, Mef−/−, and Rad50s/s B cells, thus the plasma cell neoplasms found in Mef−/−Rad50s/s mice may result from Rad50s-driven oncogenesis. This novel Mef−/−Rad50s/s myeloma animal model should be useful for the drug screening of novel anti-myeloma compounds, as well as defining the pathogenesis of multiple myeloma/plasma cell neoplasms. Disclosures: No relevant conflicts of interest to declare.


1993 ◽  
Vol 178 (3) ◽  
pp. 1091-1096 ◽  
Author(s):  
P Corradini ◽  
M Boccadoro ◽  
C Voena ◽  
A Pileri

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.


Blood ◽  
1994 ◽  
Vol 84 (6) ◽  
pp. 1922-1930 ◽  
Author(s):  
T Goto ◽  
SJ Kennel ◽  
M Abe ◽  
M Takishita ◽  
M Kosaka ◽  
...  

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.


Blood ◽  
1994 ◽  
Vol 84 (6) ◽  
pp. 1922-1930 ◽  
Author(s):  
T Goto ◽  
SJ Kennel ◽  
M Abe ◽  
M Takishita ◽  
M Kosaka ◽  
...  

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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