Biological and Molecular Characterization by Integrative Genomics Approach of CMA-03/06, a Newly Established Interleukin-6 Independent Variant of the CMA-03 Human Myeloma Cell Line.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1814-1814
Author(s):  
Donata Verdelli ◽  
Lucia Nobili ◽  
Katia Todoerti ◽  
Laura Mosca ◽  
Sonia Fabris ◽  
...  

Abstract Abstract 1814 Poster Board I-840 Background The growth and survival of multiple myeloma (MM) cells in the bone marrow microenvironment is regulated by functional complex interactions between the tumor cells and the surrounding bone marrow stromal cells mediated by adhesion molecules and the production of several cytokines of which interleukin-6 (IL-6) has been identified as the most important. Major advances in the investigation of MM biology were made possible by the availability of human myeloma cell lines (HMCLs). The IL-6-dependent CMA-03 cell line was established in our laboratory from a peritoneal effusion of a refractory relapsed MM patient. By gradually decreasing the IL-6 added to the culture, an IL-6-independent variant, CMA-03/06, could be obtained. Aims. To perform a biological and molecular characterization of this novel cell line, and to provide insights into the signaling pathways and target genes involved in the growth and survival of CMA-03/06. Methods. The growth, immunophenotypic, cytogenetic and fluorescence in situ hybridization (FISH) characterization of CMA-03/06 cell line was performed by means of standard procedures. IL-6 production into the culture media was determined using a high sensitivity IL-6 specific ELISA. Genome-wide profiling data were generated by means of Affymetrix GeneChip® Human Mapping 250K Nsp arrays; copy number (CN) alterations were calculated using the DNAcopy Bioconductor package, based on circular binary segmentation method. Global gene expression profiling (GEP) was performed by means of the GeneChip® Human Gene 1.0 ST Arrays (Affymetrix); the supervised analyses were done using the SAM software version 3.0. Results Unlike CMA-03, the addition of IL-6 to the culture medium of CMA-03/06 cells or co-culture with multipotent mesenchymal stromal cells did not induce an increase in CMA-03/06 proliferation. IL-6 was not detected in the supernatants from either CMA-03 or CMA-03/06 cell lines within 48 h, suggesting that the IL-6 independence of CMA03/06 cells is not a result of the development of an autocrine IL-6 loop. Nevertheless, IL-6 induced the activation of STAT3 and STAT1 in both cell lines, even if a slight constitutive STAT3 phosphorylation was found in CMA-03/06. The immunophenotypic analysis showed a significant difference in the expression of three antigens in the 2 cell lines: CD45 was considerably reduced in CMA-03/06 cells, whereas they were found positive for both chains of IL-6 receptor, CD126 and CD130, almost undetectable in CMA-03. Conventional cytogenetic and FISH analyses did not reveal differences between the 2 HMCLs. The genome-wide analysis allowed the identification of about 100 altered chromosomal regions common to both HMCLs, mostly DNA gains. Comparison of CMA-03/06 and CMA-03 cells evidenced a different CN in only 15 small chromosomal regions, 8 of which did not contain any transcript, whereas few genes were located on the other ones. GEP analysis of CMA-03/06 compared with CMA-03 identified 21 upregulated and 47 downregulated genes, many of which particularly relevant for MM biology, mainly involved in cellular signaling, cell cycle, cell adhesion, cell development, regulation of transcription, immunologic, inflammatory or defense activity, apoptosis. None of the genes differentially expressed in CMA-03/06 compared with CMA-03 except 1 were positioned on the chromosomal regions showing a different CN. Finally, CMA-03/06 cell line showed a lower susceptibility to camptothecin-induced apoptosis compared to CMA-03 cells. Conclusions Our data show the IL-6 independence of CMA-03/06 cell line in the absence of an autocrine IL-6 loop; the cells, however, maintain the IL-6 signaling pathway responsiveness. A consistent number of genes particularly relevant for MM biology were found deregulated in CMA-03/06 cell line compared with CMA-03. Furthermore, CMA-03/06 cell line shows an increased resistance to apoptosis. The novel CMA03/06 cell line may thus represent a suitable model for studies investigating molecular mechanisms involved in clonal evolution towards IL-6 and/or stroma-independent growth and survival of myeloma cells. Disclosures No relevant conflicts of interest to declare.

Blood ◽  
1993 ◽  
Vol 82 (12) ◽  
pp. 3712-3720 ◽  
Author(s):  
H Uchiyama ◽  
BA Barut ◽  
AF Mohrbacher ◽  
D Chauhan ◽  
KC Anderson

Previous studies show that human myeloma-derived cell lines specifically adhere to fibronectin (FN) through very late antigen-4 (VLA-4; alpha 4 beta 1 integrin complex) and RGD-peptide mechanisms, which may contribute to the localization of tumor cells in bone marrow (BM). In these studies, we characterized the adhesion of myeloma- derived cell lines to both normal and myeloma BM stromal cells (BMSCs) and the effect of adhesion on DNA synthesis. Because interleukin-6 (IL- 6) plays an important role in the pathogenesis of multiple myeloma, we also examined the effects of tumor cell adhesion on IL-6 secretion by BMSCs. In 51chromium binding assays, the U266, ARH-77, and IM-9 cell lines showed 52% +/- 12%, 55% +/- 6%, and 47% +/- 7% specific adherence, respectively, to normal BMSCs and 74% +/- 4%, 60% +/- 3%, and 61% +/- 6% specific adherence, respectively, to myeloma BMSCs. In contrast, only 12% to 13% specific binding of HS-Sultan cells to BMSCs was noted. The binding of myeloma cells to BMSCs was partially blocked with anti-beta 1 monoclonal antibody (MoAb), anti-beta 2 integrin MoAb, and excess RGD peptide, suggesting multiple mechanisms for the adhesion of myeloma cell lines to BMSCs. Binding of cell lines to FN or myeloma BMSCs did not affect cell line proliferation; however, adhesion of myeloma cell lines to normal BMSCs decreased DNA synthesis, ie, stimulation indices are 0.1 +/- 0.04, 0.2 +/- 0.1, 0.2 +/- 0.07, and 0.1 +/- 0.06 for the adherent non-IL-6-dependent U266, ARH-77, HS- Sultan, and IM-9 cells, respectively (n = 5, P < .01). In contrast, adherence of IL-6-dependent B9 cells increased their proliferation (stimulation index, 3.2 +/- 0.7). Significant (twofold to eightfold) increases in IL-6 secretion were evident in cell line-adherent (> or = 12 hours) normal and myeloma BMSC cultures. Paraformaldehyde fixation of BMSCs before adhesion completely abrogated IL-6 secretion, suggesting that IL-6 secretion was triggered in BMSCs rather than in cell lines. Partial blocking of cell line adhesion to BMSCs, using anti- beta 1 integrin and anti-beta 2 integrin MoAbs and RGD peptide, also partially blocked the triggering of IL-6 secretion by BMSCs. When cell lines were placed in Transwell inserts and then cultured with either normal or myeloma BMSCs, permitting juxtaposition without cell to cell contact between myeloma cell lines and BMSCs, no increase in IL-6 secretion was observed.(ABSTRACT TRUNCATED AT 400 WORDS)


Blood ◽  
1993 ◽  
Vol 82 (12) ◽  
pp. 3712-3720 ◽  
Author(s):  
H Uchiyama ◽  
BA Barut ◽  
AF Mohrbacher ◽  
D Chauhan ◽  
KC Anderson

Abstract Previous studies show that human myeloma-derived cell lines specifically adhere to fibronectin (FN) through very late antigen-4 (VLA-4; alpha 4 beta 1 integrin complex) and RGD-peptide mechanisms, which may contribute to the localization of tumor cells in bone marrow (BM). In these studies, we characterized the adhesion of myeloma- derived cell lines to both normal and myeloma BM stromal cells (BMSCs) and the effect of adhesion on DNA synthesis. Because interleukin-6 (IL- 6) plays an important role in the pathogenesis of multiple myeloma, we also examined the effects of tumor cell adhesion on IL-6 secretion by BMSCs. In 51chromium binding assays, the U266, ARH-77, and IM-9 cell lines showed 52% +/- 12%, 55% +/- 6%, and 47% +/- 7% specific adherence, respectively, to normal BMSCs and 74% +/- 4%, 60% +/- 3%, and 61% +/- 6% specific adherence, respectively, to myeloma BMSCs. In contrast, only 12% to 13% specific binding of HS-Sultan cells to BMSCs was noted. The binding of myeloma cells to BMSCs was partially blocked with anti-beta 1 monoclonal antibody (MoAb), anti-beta 2 integrin MoAb, and excess RGD peptide, suggesting multiple mechanisms for the adhesion of myeloma cell lines to BMSCs. Binding of cell lines to FN or myeloma BMSCs did not affect cell line proliferation; however, adhesion of myeloma cell lines to normal BMSCs decreased DNA synthesis, ie, stimulation indices are 0.1 +/- 0.04, 0.2 +/- 0.1, 0.2 +/- 0.07, and 0.1 +/- 0.06 for the adherent non-IL-6-dependent U266, ARH-77, HS- Sultan, and IM-9 cells, respectively (n = 5, P < .01). In contrast, adherence of IL-6-dependent B9 cells increased their proliferation (stimulation index, 3.2 +/- 0.7). Significant (twofold to eightfold) increases in IL-6 secretion were evident in cell line-adherent (> or = 12 hours) normal and myeloma BMSC cultures. Paraformaldehyde fixation of BMSCs before adhesion completely abrogated IL-6 secretion, suggesting that IL-6 secretion was triggered in BMSCs rather than in cell lines. Partial blocking of cell line adhesion to BMSCs, using anti- beta 1 integrin and anti-beta 2 integrin MoAbs and RGD peptide, also partially blocked the triggering of IL-6 secretion by BMSCs. When cell lines were placed in Transwell inserts and then cultured with either normal or myeloma BMSCs, permitting juxtaposition without cell to cell contact between myeloma cell lines and BMSCs, no increase in IL-6 secretion was observed.(ABSTRACT TRUNCATED AT 400 WORDS)


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1845-1845
Author(s):  
Kathleen A. Donovan ◽  
Laurie L. Moon-Tasson ◽  
Alexander E. Hromockyj ◽  
Debra M Meyer ◽  
Andrew D Stone ◽  
...  

Abstract Abstract 1845 Inflammation is a driving factor in the pathogenesis of many cancers including multiple myeloma (MM). The active role that cytokines play, IL-1β in particular, during the early stages of MM has been extensively characterized. Myeloma is a plasma cell tumor whose early stages are characterized by cytokine dependent growth, predominantly driven by IL-6. We have demonstrated that IL-1β is a key inducer of IL-6 expressed by bone marrow stromal cells in a paracrine fashion during the progression of multiple myeloma from smoldering myeloma (SMM) to active disease (Mayo Clinic Proc 84:114 (Feb. 2009)). Elevated ATP levels have been documented in vivo in tumor micro-environments and is a potential contributing factor to IL-1β induced inflammation. The P2X7 receptor (P2X7R) is an ATP-gated ion channel expressed by cells of the hematopoetic lineage that has been shown to play a critical role in IL-1b processing and secretion. We investigated the role this receptor may have in the release of IL-1β in the bone marrow microenvironment using bone marrow samples from both chemotherapy treated and untreated patients. Myeloma cell lines were evaluated by RT-PCR for the expression of P2X7R mRNA. Expression was detected and confirmed by sequencing in ANBL-6, MM1.S, U266, RPMI-8226 and KAS-6/1 and was comparable to U937, a previously characterized P2X7R positive cell line. A newly derived plasmacytoma cell line, PCYT3, showed very low levels of message expression. The ability of ATP, the P2X7R agonist, to trigger the processing and release of IL-1β by activation of the P2X7 channel was studied using KAS-Pro, a myeloma cell line stably transfected with a pro- IL-1β gene. IL-1β, measured by ELISA, was released in a dose dependent fashion in response to increasing amounts of ATP ranging from.6mM to 5mM. Four P2X7R specific antagonists were tested for their effect on ATP stimulated IL- 1β release from KAS-Pro; all 4 compounds demonstrated inhibition in a dose dependent manner with varying degrees of potency correlating with P2X7R inhibition. In addition fresh patient samples (8 MGUS/7SMM/9 newly diagnosed MM as well as 12 Treated MM) were evaluated for receptor expression and function. All stages of disease expressed the receptor by RT-PCR. Analysis of samples from all stages of MM, as measured directly by IL-1β ELISA as well as indirectly by measurement of IL-1β induced IL-6 production from normal bone marrow stromal cells, showed functional receptor activation in response to ATP stimulation. IL-6 production detected from MGUS patient samples had a mean result of 2,253 pg/ml, the mean for SMM was 5,495 pg/ml, MM were 6,875 pg/ml while treated MM samples showed a mean result of 15,219 pg/m. Greater than 90% inhibition of IL-1β release by the P2X7R antagonists was seen for all patients who demonstrated a positive ATP induced IL-1β release (see figure). We observed a greater than 2 fold increase in IL-1β release between the treated MM samples and the newly diagnosed MM samples, suggesting a chemotherapy induced inflammation process may be ongoing in these patients. These results confirm the activity of functional P2X7 receptors on myeloma cell lines and in fresh patient samples and suggest a role for the use of P2X7 receptor antagonists in the therapy of myeloma, particularly in patients undergoing chemotherapy. Disclosures: Hromockyj: Pfizer Corporation: Employment. Meyer:Pfizer Corporation: Employment.


Blood ◽  
1996 ◽  
Vol 87 (8) ◽  
pp. 3375-3383 ◽  
Author(s):  
T Tsujimoto ◽  
IA Lisukov ◽  
N Huang ◽  
MS Mahmoud ◽  
MM Kawano

By using two-color phenotypic analysis with fluorescein isothiocyanate- anti-CD38 and phycoerythrin-anti-CD19 antibodies, we found that pre-B cells (CD38+CD19+) signifcantly decreased depending on the number of plasma cells (CD38++CD19+) in the bone marrow (BM) in the cases with BM plasmacytosis, such as myelomas and even polyclonal gammopathy. To clarify how plasma cells suppress survival of pre-B cells, we examined the effect of plasma cells on the survival of pre-B cells with or without BM-derived stromal cells in vitro. Pre-B cells alone rapidly entered apoptosis, but interleukin-7 (IL-7), a BM stromal cell line (KM- 102), or culture supernatants of KM-102 cells could support pre-B cell survival. On the other hand, inhibitory factors such as transforming growth factor-beta1 (TGF-beta1) and macrophage inflammatory protein- 1beta (MIP-1beta) could suppress survival of pre-B cells even in the presence of IL-7. Plasma cells alone could not suppress survival of pre- B cells in the presence of IL-7, but coculture of plasma cells with KM- 102 cells or primary BM stromal cells induced apoptosis of pre-B cells. Supernatants of coculture with KM-102 and myeloma cell lines (KMS-5) also could suppress survival of pre-B cells. Furthermore, we examined the expression of IL-7, TGF-beta1, and MIP-1beta mRNA in KM-102 cells and primary stromal cells cocultured with myeloma cell lines (KMS-5). In these cells, IL-7 mRNA was downregulated, but the expression of TGF- beta1 and MIP-1beta mRNA was augmented. Therefore, these results suggest that BM-derived stromal cells attached to plasma (myeloma) cells were modulated to secrete lesser levels of supporting factor (IL- 7) and higher levels of inhibitory factors (TGF-beta1 and MIP-1beta) for pre-B cell survival, which could explain why the increased number of plasma (myeloma) cells induced suppression of pre-B cells in the BM. This phenomenon may represent a feedback loop between pre-B cells and plasma cells via BM stromal cells in the BM.


Blood ◽  
1991 ◽  
Vol 78 (8) ◽  
pp. 1996-2004 ◽  
Author(s):  
JK Hitzler ◽  
H Martinez-Valdez ◽  
DB Bergsagel ◽  
MD Minden ◽  
HA Messner

Abstract Interleukin-6 (IL-6) has been shown to stimulate the proliferation of multiple myeloma cells purified to a high degree from human bone marrow. IL-6 production in multiple myeloma has been attributed to cells belonging to the myeloma clone, thus supporting a mechanism of autostimulation. In addition, it has been shown that IL-6 may be produced by auxiliary cell populations of the bone marrow that are not part of the myeloma clone. A definitive separation of both putative sources for IL-6 may be difficult to achieve in fresh patient IL-6 growth requirement and production by pure myeloma cell populations using seven human myeloma cell lines (OCI-My 1 to 7) that were established from patients with advanced disease. The proliferative response of each line to recombinant IL-6 was measured in a clonogenic assay providing human plasma and methylcellulose as a viscous support and by 3H-thymidine uptake in liquid suspension culture. We observed marked heterogeneity, ranging from IL-6-dependent colony formation by OCI-My 4, to IL-6-independent growth. All lines expressed mRNA for the IL-6 receptor. Expression of IL-6 mRNA was analyzed after amplification by polymerase chain reaction and was present in five of seven lines. IL- 6 protein was detected by enzyme-linked immunosorbent assay (ELISA) in the culture supernatants of two lines (OCI-My 3 and 2). Its functional activity was confirmed in a bioassay using the IL-6-dependent murine hybridoma line B 13.29. This activity was neutralized by anti-IL-6 antibody. Two lines did not express mRNA for IL-6. The remaining three lines expressed mRNA for IL-6, but did not secrete IL-6 protein. Immunoprecipitation experiments with lysates of one of these three lines did not detect the presence of IL-6 protein. These results suggest that autocrine stimulation by IL-6 may occur in some cell lines derived from patients with multiple myeloma. However, it does not represent a universal mechanism in myeloma cell growth.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2328-2328
Author(s):  
Katja C. Weisel ◽  
Ying Gao ◽  
Jae-Hung Shieh ◽  
Lothar Kanz ◽  
Malcolm A.S. Moore

Abstract The aorta-gonads-mesonephros (AGM) region autonomously generates adult repopulating hematopoietic stem cells (HSC) in the mouse embryo and provides its own HSC-supportive microenvironment. Stromal cells from adult bone marrow, yolk sac, fetal liver and AGM have been used in coculture systems for analysing growth, maintenance and differentiation of hematopoietic stem cells. We generated &gt;100 cloned stromal cell lines from the AGM of 10.5 dpc mouse embryos. In previous studies, we tested these for support of murine adult and human cord blood (CB) CD34+ cells. We could demonstrate that 25 clones were superior to the MS5 bone marrow stromal cell line in supporting progenitor cell expansion of adult mouse bone marrow both, in 2ndry CFC and CAFC production. In addition we demonstrated that 5 AGM lines promoted in absence of exogenous growth factors the expansion of human CB cells with progenitor (CFC production for at least 5 weeks) and stem cell (repopulation of cocultured cells in NOD/SCID assay) function. Now, we could show that one of the isolated stromal cell lines (AGM-S62) is capable in differentiating undifferentiated murine embryonic stem (mES) cells into cells of the hematopoietic lineage. A sequential coculture of mES-cells with AGM-S62 showed production of CD41+ hematopoietic progenitor cells at day 10 as well as 2ndry CFC and CAFC production of day 10 suspension cells. Hematopoietic cell differentiation was comparable to standard OP9 differentiation assay. With these data, we can describe for the first time, that a stromal cell line other than OP9 can induce hematopoietic differentiation of undifferentiated mES cells. Hematopoietic support occurs independently of M-CSF deficiency, which is the characteristic of OP9 cells, because it is strongly expressed by AGM-S62. To evaluate genes responsible for hematopoietic cell support, we compared a supporting and a non-supporting AGM stromal cell line by microarray analysis. The cell line with hematopoietic support clearly showed a high expression of mesenchymal markers (laminins, thrombospondin-1) as well as characteristic genes for the early vascular smooth muscle phenotype (Eda). Both phenotypes are described for stromal cells with hematopoietic support generated from bone marrow and fetal liver. In addition, the analysed supporting AGM stromal cell line interestingly expressed genes important in early B-cell differentiation (osteoprotegerin, early B-cell factor 1, B-cell stimulating factor 3), which goes in line with data demonstrating early B-cell development in the AGM-region before etablishing of fetal liver hematopoiesis. Further studies will show the significance of single factors found to be expressed in microarray analyses. This unique source of &gt; 100 various cell lines will be of value in elucidating the molecular mechanisms regulating embryonic and adult hematopoiesis in mouse and man.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3673-3673
Author(s):  
Rentian Feng ◽  
Jorge A Rios ◽  
Markus Mapara ◽  
Suzanne Lentzsch

Abstract Patients with relapsed multiple myeloma (MM) previously treated with bortezomib and lenalidomide often fail to respond to further therapies. To identify potential new treatment approaches for MM, we used Luminex technology to screen a library of 1,120 compounds provided by the Multiple Myeloma Research Foundation. By multiplex cytokine array, we identified benzimidazoles including the anthelmintics mebendazole, fenbendazole, albendazole, nocodazole and pyrvinium pamoate, as inhibiting the production of cytokines essential for MM cell growth and survival, such as IL-6 (inhibition rate 40–70%), MIP-1α (inhibition rate 65–75%), VEGF (inhibition rate 75%), and soluble IL-6R (inhibition rate 40–52%). Consequently, these anthelmintics demonstrated dose-dependent inhibition of myeloma cell (RPMI-8226, H929, U266 and MM1S) proliferation. The lead compound, nocodazole, caused nuclear fragmentation and caspase-8 activation in MM cell lines and primary CD138+ cells in dose- and time-dependent fashion (IC50: 30–60 nM). Importantly, growth and survival signals provided by bone marrow stromal cells in bone marrow co-cultures failed to protect MM cells from nocodazole-induced cell death. In the apoptotic cells, caspase-8 was more activated than caspase-9, suggesting that mitochondrial signaling is not a major apoptotic pathway. Cell cycle analysis indicated that G2/M cell cycle arrest reached a peak at 17 hr. Sub-G1 proportion was strongly increased after treatment for 24 hr in all tested cell lines. Electron microscope (EM) and nuclear staining studies consistently showed the accumulation of metaphase cells, and morphologic elongation at 7 hr, at which time G2/M arrest was obvious. Most of the elongated cells had only one nucleus, suggesting that they failed to progress to mitosis due to overall microtubular network disarray. We conclude that nocodazole exposure induced microtubular network disarray with cell elongation, and G2/M arrest with a late stage mitotic block resulting in cell death. Benzimidazoles including nocodazole, traditionally used as antihelmintic drugs, have shown antitumor activity against hepatocellular, lung and adrenocortical carcinoma, and melanoma. In our study, we identified the anthelmintic compound nocodazole as a new anti-myeloma agent. Nocodazole warrants further investigation for its anti-MM effects in vitro and in vivo.


Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3622-3622
Author(s):  
Yang Liu ◽  
Shenghua Duan ◽  
Xavier Leleu ◽  
Yong Zhang ◽  
Abdel Kareem A. Azab ◽  
...  

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


Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2946-2946
Author(s):  
Catherine M Gavile ◽  
Jayakumar R Nair ◽  
Kelvin P Lee ◽  
Sagar Lonial ◽  
Lawrence H. Boise

Abstract Abstract 2946 Multiple myeloma (MM) is a hematologic malignancy characterized by the aberrant proliferation of plasma cells. Myeloma cells retain most of the physiological characteristics of their normal counterpart – the long-lived plasma cell. Myeloma cells secrete immunoglobulin and reside in the bone marrow, where they rely heavily on interactions with the stroma for survival signals. While recent advances in therapeutics have led to an increase in median survival post-diagnosis, the disease remains incurable. Understanding the pathways which mediate growth and survival of these cells will help in identifying new targets that can potentially further improve patient outcomes. CD28 is a receptor better known for its role in T-cell signaling through interaction with its ligands, CD80 or CD86. Interaction between CD28 on T-cells and CD80/86 on antigen-presenting cells leads to survival and proliferation of T-cells. Recent work has shown that the CD80/86-CD28 pathway also plays an important role in normal plasma cell generation and survival. Interestingly, high expression of CD28 and CD86 are poor prognostic markers for myeloma patients. Previous work has shown that CD28 activation provides survival signals for myeloma cells in growth-factor deficient conditions. It has also been shown that CD28 on the myeloma cell interacts with CD80/86 on the dendritic cell, which induces secretion of IL-6 (by the DC), an important myeloma growth factor. However, it is not known if CD28 or CD86 play a role in steady state growth and survival of myeloma cells. In order to determine the role of each of these 2 molecules in myeloma physiology, we knocked-down either CD28 or CD86 on the myeloma cell via lentivirus-mediated shRNAs. We found that knockdown of CD86 leads to apoptosis in 3 myeloma cell lines (RPMI8226, MM1.s, and KMS18). Four days after infection with the lentivirus containing shCD86, 45.7±4.9 and 60.3±4.6 percent control apoptosis was observed in RPMI8226 and MM1.s respectively, while less death was observed in KMS18 (17.6±1.6). CD28-knockdown resulted in apoptosis as well (24.9±4.3 for RPMI8226, 26.8±4.1 for MM1s, 21.8±3.8 for KMS18, percent control apoptosis). Consistent with these findings, we were unable to establish a myeloma cell line with stable knockdown of either CD28 or CD86. Additionally, RPMI8226 cells stably transfected to over-express either Bcl-2, Bcl-xL, or Mcl-1 are protected from cell death induced by CD86 or CD28 silencing. These data suggest that CD28 and CD86 are essential to prevent apoptosis of myeloma cells in vitro. To confirm these findings we determined the effects of CTLA4-Ig on myeloma survival. CTLA4-Ig inhibits CD86-CD28 signaling by binding to CD86, blocking its interaction with CD28. We found that treatment of RPMI8226 and MM1.s cells with CTLA4-Ig caused apoptosis in the myeloma cells after 2 days (23.9±3.9 for RPMI8226 and 20.4±6.2 for MM1.s, percent control apoptosis). Thus like normal plasma cells, CD28 and CD86 are required for the survival of myeloma cells. To determine why silencing of CD86 has a more potent effect than CD28 silencing on myeloma cell survival in 2 out of 3 cell lines, we investigated the effects of silencing on cell surface expression of each of these proteins. CD28 and CD86 mRNA and protein levels were silenced to similar levels by their cognate hairpins. However, in MM.1s and RPMI8226 we found that silencing of CD28 resulted in an increase in CD86 surface expression. This increase was also observed at the mRNA level and in the cells over-expressing Bcl-2 family members, indicating that this is not simply due to the selection of the highest expressing cells. These data suggest a feedback loop exists to regulate CD28-CD86 signaling in myeloma cells. Surprisingly, in the KMS18 cell line, we observe the converse effect, where silencing of CD86 resulted in upregulation of CD28. This provides a likely explanation for why these cells are less susceptible to CD86 silencing than the other two lines. Interestingly, blocking CD86 with CTLA4-Ig treatment also resulted in a modest upregulation in CD28 surface expression of MM.1s and RPMI8226, which suggests that silencing CD86 and binding of CD86 with a soluble receptor are not equivalent, and that multiple signaling feedback pathways exist to regulate the expression of this receptor-ligand pair that is necessary for myeloma cell survival. Disclosures: No relevant conflicts of interest to declare.


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