51
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Lombardi L, Poretti G, Mattioli M, Fabris S, Agnelli L, Bicciato S, Kwee I, Rinaldi A, Ronchetti D, Verdelli D, Lambertenghi-Deliliers G, Bertoni F, Neri A. Molecular characterization of human multiple myeloma cell lines by integrative genomics: Insights into the biology of the disease. Genes Chromosomes Cancer 2007; 46:226-38. [PMID: 17171682 DOI: 10.1002/gcc.20404] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
To investigate the patterns of genetic lesions in a panel of 23 human multiple myeloma cell lines (HMCLs), we made a genomic integrative analysis involving FISH, and both gene expression and genome-wide profiling approaches. The expression profiles of the genes targeted by the main IGH translocations showed that the WHSC1/MMSET gene involved in t(4;14)(p16;q32) was expressed at different levels in all of the HMCLs, and that the expression of the MAF gene was not restricted to the HMCLs carrying t(14;16)(q32;q23). Supervised analyses identified a limited number of genes specifically associated with t(4;14) and involved in different biological processes. The signature related to MAF/MAFB expression included the known MAF target genes CCND2 and ITGB7, as well as genes controlling cell shape and cell adhesion. Genome-wide DNA profiling allowed the identification of a gain on chromosome arm 1q in 88% of the analyzed cell lines, together with recurrent gains on 8q, 18q, 7q, and 20q; the most frequent deletions affected 1p, 13q, 17p, and 14q; and almost all of the cell lines presented LOH on chromosome 13. Two hundred and twenty-two genes were found to be simultaneously overexpressed and amplified in our panel, including the BCL2 locus at 18q21.33. Our data further support the evidence of the genomic complexity of multiple myeloma and reinforce the role of an integrated genomic approach in improving our understanding of the molecular pathogenesis of the disease. This article contains Supplementary Material available at http://www.interscience.wiley.com/jpages/1045-2257/suppmat.
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Affiliation(s)
- Luigia Lombardi
- Centro di Genetica Molecolare ed Espressione Genica, Fondazione IRCCS Policlinico, Milan, Italy
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52
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Obeng EA, Carlson LM, Gutman DM, Harrington WJ, Lee KP, Boise LH. Proteasome inhibitors induce a terminal unfolded protein response in multiple myeloma cells. Blood 2006; 107:4907-16. [PMID: 16507771 PMCID: PMC1895817 DOI: 10.1182/blood-2005-08-3531] [Citation(s) in RCA: 883] [Impact Index Per Article: 49.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2005] [Accepted: 02/13/2006] [Indexed: 02/07/2023] Open
Abstract
Multiple myeloma (MM) is an incurable plasma cell malignancy. The 26S proteasome inhibitor, bortezomib, selectively induces apoptosis in MM cells; however, the nature of its selectivity remains unknown. Here we demonstrate that 5 different MM cell lines display similar patterns of sensitivity to 3 proteasome inhibitors (PIs) but respond differently to specific NF-kappaB inhibition. We further show that PIs initiate the unfolded protein response (UPR), a signaling pathway activated by the accumulation of misfolded proteins within the endoplasmic reticulum (ER). Consistent with reports that prosurvival/physiologic UPR components are required for B-cell differentiation into antibody-secreting cells, we found that MM cells inherently expressed the ER chaperones GRP78/Bip and GRP94/gp96. However, bortezomib rapidly induced components of the proapoptotic/terminal UPR, including PERK, the ER stress-specific eIF-2alpha kinase; ATF4, an ER stress-induced transcription factor; and its proapoptotic target, CHOP/GADD153. Consistent with our hypothesis that PIs induce the accumulation of misfolded ER-processed proteins, we found that the amount of immunoglobulin subunits retained within MM cells correlated with their sensitivity to PIs. These findings suggest that MM cells have a lower threshold for PI-induced UPR induction and ER stress-induced apoptosis because they constitutively express ER stress survival factors to function as secretory cells.
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Affiliation(s)
- Esther A Obeng
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, FL 33101, USA
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53
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Taylor BJ, Reiman T, Pittman JA, Keats JJ, de Bruijn DRH, Mant MJ, Belch AR, Pilarski LM. SSX cancer testis antigens are expressed in most multiple myeloma patients: co-expression of SSX1, 2, 4, and 5 correlates with adverse prognosis and high frequencies of SSX-positive PCs. J Immunother 2006; 28:564-75. [PMID: 16224274 DOI: 10.1097/01.cji.0000175685.36239.e5] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Cancer testis antigens (CTAs) are tumor-specific antigens that may be useful targets for cancer vaccines. Here, CTA expression was examined in multiple myeloma (MM), a B-cell cancer characterized by malignant plasma cells (PCs) in the bone marrow (BM), and monoclonal gammopathy of undetermined significance (MGUS), a condition that can progress to MM. We screened a panel of patient BMs at different stages of malignancy for CTA expression by reverse transcription polymerase chain reaction RT-PCR. Here, SSX (synovial sarcoma, X chromosome) emerged as a promising candidate for an MM vaccine, having a profile similar to currently studied CTA, NY-ESO-1, and MAGE. SSX1, 2, 4, and 5 expression was studied further in 114 MM (total SSX, 61% of patients; SSX1, 42%; SSX2, 23%; SSX4, 38%; SSX5, 35%), 45 MGUS (total SSX, 24% of patients; SSX1, 9%; SSX4, 20%), and 12 control (0/12, 0%) subjects. Several expression patterns were observed, the most predominant being co-expression of SSX1, 2, 4, and 5 (called group A expression, in 20% of MM), which correlated with reduced survival (P=0.0006). Of the four genes, SSX2 had the strongest association with reduced survival (P=0.0001). SSX protein expression ranged from 13.5% of PCs in an SSX1/SSX4 co-expressor to as high as 88% of PCs in group A expressor, exceeding reported frequencies of NY-ESO-1 and MAGE in MM. In single PCs from group A patients, we detected variable degrees of SSX co-expression, emphasizing the heterogeneity of CTA expression within tumor cell populations. These results demonstrate that SSX is a frequently expressed CTA in MM and highlight its potential as an MM vaccine candidate.
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Affiliation(s)
- Brian J Taylor
- Department of Oncology, Cross Cancer Institute, and Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
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54
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Proteasome inhibitors induce a terminal unfolded protein response in multiple myeloma cells. Blood 2006. [PMID: 16507771 DOI: 10.1182/blood-2005-08-3531;] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Multiple myeloma (MM) is an incurable plasma cell malignancy. The 26S proteasome inhibitor, bortezomib, selectively induces apoptosis in MM cells; however, the nature of its selectivity remains unknown. Here we demonstrate that 5 different MM cell lines display similar patterns of sensitivity to 3 proteasome inhibitors (PIs) but respond differently to specific NF-kappaB inhibition. We further show that PIs initiate the unfolded protein response (UPR), a signaling pathway activated by the accumulation of misfolded proteins within the endoplasmic reticulum (ER). Consistent with reports that prosurvival/physiologic UPR components are required for B-cell differentiation into antibody-secreting cells, we found that MM cells inherently expressed the ER chaperones GRP78/Bip and GRP94/gp96. However, bortezomib rapidly induced components of the proapoptotic/terminal UPR, including PERK, the ER stress-specific eIF-2alpha kinase; ATF4, an ER stress-induced transcription factor; and its proapoptotic target, CHOP/GADD153. Consistent with our hypothesis that PIs induce the accumulation of misfolded ER-processed proteins, we found that the amount of immunoglobulin subunits retained within MM cells correlated with their sensitivity to PIs. These findings suggest that MM cells have a lower threshold for PI-induced UPR induction and ER stress-induced apoptosis because they constitutively express ER stress survival factors to function as secretory cells.
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55
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Tinhofer I, Biedermann R, Krismer M, Crazzolara R, Greil R. A role of TRAIL in killing osteoblasts by myeloma cells. FASEB J 2006; 20:759-61. [PMID: 16436464 DOI: 10.1096/fj.05-4329fje] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In multiple myeloma (MM), neoplastic plasma cells accumulate in the bone marrow where their survival, proliferation, and apoptosis are controlled at multiple levels by interaction with the bone marrow microenvironment. Myeloma cells actively control these interactions by activating stromal and endothelial cells for production of survival factors, such as interleukin-6, and suppressing other cell types such as erythroblasts, normal B cell progenitors, and T-cells. In the present study, we identified primary osteoblasts as additional potential targets for myeloma cell-mediated suppression which was partly dependent on the death receptor ligand TRAIL. Besides killing of osteoblasts, myeloma cell lines sensitized osteoblasts to cell death mediated by recombinant TRAIL, whereas primary osteoblasts protected myeloma cells from TRAIL-mediated apoptosis that was mediated by osteoprotegerin (OPG). Besides increase of osteoclastogenesis and osteoclast activity, suppression of bone-forming cells by myeloma cells might contribute to bone loss in MM patients. In addition, clinical development of recombinant TRAIL as anti-myeloma therapy should include evaluation of potential side effects on viability of normal bone cells.
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Affiliation(s)
- Inge Tinhofer
- Laboratory of Immunological and Molecular Cancer Research, 3rd Medical Department of the Salzburg General Hospital and Private Paracelsus Medical University, Salzburg, Austria.
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56
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Lin B, Catley L, LeBlanc R, Mitsiades C, Burger R, Tai YT, Podar K, Wartmann M, Chauhan D, Griffin JD, Anderson KC. Patupilone (epothilone B) inhibits growth and survival of multiple myeloma cells in vitro and in vivo. Blood 2005; 105:350-7. [PMID: 15367426 DOI: 10.1182/blood-2004-06-2499] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
In this study, we investigated the in vitro and in vivo efficacy of patupilone (epothilone B, EPO906), a novel nontaxane microtubule stabilizing agent, in treatment of multiple myeloma (MM). Patupilone directly inhibited growth and survival of MM cells, including those resistant to conventional chemotherapies, such as the taxane paclitaxel. Patupilone induced G2M arrest of MM cells, with subsequent apoptosis. Interleukin-6 (IL-6) and insulin-like growth factor-1 (IGF-1), 2 known growth and survival factors for MM, did not protect MM.1S cells against patupilone-induced cell death. Proliferation of MM cells induced by adherence to bone marrow stromal cells (BMSCs) was also inhibited by patupilone and was paralleled by down-regulation of vascular endothelial growth factor (VEGF) secretion. Importantly, stimulation of cells from patients with MM, either with IL-6 or by adherence to BMSCs, enhanced the anti-proliferative and proapoptotic effects of patupilone. Moreover, patupilone was effective against MM cell lines that overexpress the MDR1/P-glycoprotein multidrug efflux pump. In addition, patupilone was effective in slowing tumor growth and prolonging median survival of mice that received orthotopical transplants with MM tumor cells. Taken together, these preclinical findings suggest that patupilone may be a safe and effective drug in the treatment of MM, providing the framework for clinical studies to improve patient outcome in MM. (Blood. 2005;105:350-357)
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Affiliation(s)
- Boris Lin
- Jerome Lipper Multiple Myeloma Center, Department of Adult Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
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57
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Caers J, Asosingh K, Van Riet I, Van Camp B, Vanderkerken K. Of mice and men: disease models of multiple myeloma. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.ddmod.2004.11.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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58
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Matsuo Y, Drexler HG, Harashima A, Okochi A, Hasegawa A, Kojima K, Orita K. Induction of CD28 on the new myeloma cell line MOLP-8 with t(11;14)(q13;q32) expressing δ/λ type immunoglobulin. Leuk Res 2004; 28:869-77. [PMID: 15203285 DOI: 10.1016/j.leukres.2003.12.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2003] [Accepted: 12/12/2003] [Indexed: 10/26/2022]
Abstract
The novel multiple myeloma (MM) cell line MOLP-8 carrying the t(11;14) (q13;q32) was established from the peripheral blood of a 52-year-old Japanese male patient with Bence-Jones delta/lambda type MM (stage IIIA with hyperammonemia). The growth of MOLP-8 cells is constitutively independent of exogenous growth factors or feeder cells. MOLP-8 cells grow mainly as free floating single cells and slightly adherent on the bottom of the plastic culture flask. Wright-Giemsa-stained MOLP-8 cells show the typical plasma cell morphology with abundant cytoplasm, heterogeneous cell size and one to three nuclei. The immunoprofile of MOLP-8 corresponds to that seen typically in primary MM cells: positive for cytoplasmic immunoglobulin (Ig) delta/lambda chains, CD10, CD29, CD38, CD40, CD44, CD49b, CD49d, CD54, CD56, CD58, CD71, CD138 and PCA-1; the cells were negative for surface Igs and various other B-cell, T-cell and myelomonocyte-associated immunomarkers. CD28 became positive after co-culture of MOLP-8 cells with bone marrow adherent stromal (BST) feeder cells for a week. About 30% of MOLP-8 cells adhered strongly to the BST cells, but the cellular adhesion was clearly inhibited by addition of either anti-CD29 or anti-CD106 monoclonal antibody, suggesting a specific cellular adhesion through alpha4beta1-integrin-VCAM-1 interaction. The novel MOLP-8 cell line together with the present myeloma cell lines will present useful model systems in the investigation of the biology of MM.
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Affiliation(s)
- Yoshinobu Matsuo
- Fujisaki Cell Center, Hayashibara Biochemical Labs., Inc., 675-1 Fujisaki, Okayama 702-8006, Japan.
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59
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Magrangeas F, Cormier ML, Descamps G, Gouy N, Lodé L, Mellerin MP, Harousseau JL, Bataille R, Minvielle S, Avet-Loiseau H. Light-chain only multiple myeloma is due to the absence of functional (productive) rearrangement of the IgH gene at the DNA level. Blood 2004; 103:3869-75. [PMID: 14715636 DOI: 10.1182/blood-2003-07-2501] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Although most multiple myeloma (MM) cases are characterized by the detection of a monoclonal immunoglobulin in the serum, about 15% of the patients present only immunoglobulin light chains, detected either in the urine or serum or both. These patients are designated as having light-chain (LC) MM. Using fiber-fluorescent in situ hybridization, and in contrast to patients and myeloma cell lines secreting heavy chains (who presented a legitimate functional IgH rearrangement in every case), LC MM never displayed a functional IgH recombination. Interestingly, most LC MM cases presented one IgH allele with a germline configuration (including the DJ region), the second allele being usually involved in an illegitimate recombination. Of note, most of these translocations occurred close to (or at) switch regions, even though in some cases, breakpoints involving nonswitch regions were observed. Thus, this study clearly showed that LC MM is due to the absence of legitimate IgH rearrangement at the DNA level, reflecting possible abnormalities in the IgH gene recombinations during B-cell maturation. Furthermore, it showed that this defect did not prevent the activation of the switch process because most of 14q32 translocations observed in LC MM occurred at switch regions.
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Affiliation(s)
- Florence Magrangeas
- Laboratory of Hematology, Clinical Hematology Department, University Hospital, Nantes, France
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60
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Donner LR. Epstein-Barr Virus-induced Transformation of Cutaneous Plasmacytoma into CD30+ Diffuse Large B-cell Lymphoma. Am J Dermatopathol 2004; 26:63-6. [PMID: 14726824 DOI: 10.1097/00000372-200402000-00009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
A unique, previously unreported case of transformation of cutaneous plasmacytoma into CD30+ large B-cell lymphoma is described. Both neoplastic components were immunophenotypically distinct. The plasma cells were CD20-, CD30-, CD43+, CD45+, lambda +; the blasts were CD20+, CD30+, CD43-, and CD45-. The large B-cell lymphoma has gradually become a predominant component of the neoplastic nodules. While plasma cells and blasts were both positive for Epstein-Barr virus-encoded nuclear RNAs (EBER-1), the EBV-latent membrane antigen 1 (EBV-LMP1) was expressed only in the minority of the blasts and not in the plasma cells. The neoplastic process has remained confined to the skin for more than six years since its development.
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MESH Headings
- Aged
- Antibodies, Monoclonal/therapeutic use
- Antibodies, Monoclonal, Murine-Derived
- Antineoplastic Combined Chemotherapy Protocols/therapeutic use
- Biomarkers, Tumor/analysis
- Cell Transformation, Neoplastic
- Cyclophosphamide/therapeutic use
- Epstein-Barr Virus Infections/complications
- Epstein-Barr Virus Infections/pathology
- Female
- Herpesvirus 4, Human/genetics
- Herpesvirus 4, Human/immunology
- Herpesvirus 4, Human/isolation & purification
- Humans
- Immunohistochemistry
- In Situ Hybridization
- Ki-1 Antigen/analysis
- Lymphoma, B-Cell/drug therapy
- Lymphoma, B-Cell/pathology
- Lymphoma, B-Cell/virology
- Lymphoma, Large B-Cell, Diffuse/drug therapy
- Lymphoma, Large B-Cell, Diffuse/pathology
- Lymphoma, Large B-Cell, Diffuse/virology
- Plasmacytoma/drug therapy
- Plasmacytoma/pathology
- Plasmacytoma/virology
- RNA, Viral/analysis
- Rituximab
- Skin Neoplasms/drug therapy
- Skin Neoplasms/pathology
- Skin Neoplasms/virology
- Treatment Outcome
- Vincristine/therapeutic use
- Viral Matrix Proteins/analysis
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Affiliation(s)
- Ludvik R Donner
- Department of Pathology, Scott & White Memorial Hospital, The Texas A&M University System Health Science Center, College of Medicine, Temple, TX 76508, USA.
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61
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Abstract
Multiple myeloma (MM) is a neoplasm of a terminally differentiated B-cell. Human myeloma cell lines were shown to be suitable model systems for use in various fields of the biological sciences. Within the last 20 years more than 100 cell lines have been established. So-called 'myeloma cell lines' have been previously reported and are still widely used which are in reality Epstein-Barr virus (EBV)-positive B-lymphoblastoid cell lines. The presence of the EBV-genome in residual normal B-cells provides them with a selective growth advantage after explantation. Cell lines represent an extremely important resource for research in a variety of fields and disciplines. As the cell lines are used as in vitro model systems in lieu of primary material, it is crucial that the cells in the culture flasks faithfully correspond to the purported objects of study. On closer examination, the use of false cell lines may be seen to invalidate a significant percentage of scientific work, or at least cast doubts on the relevance of these in vitro results to the cell type or tumor in vivo. Ultimately, use of cross-contaminated cell lines is a waste of human and material resources. Henceforth, it should be mandatory to prove the proper derivation of each new cell line by comparing DNA fingerprints or karyotypes of the patient's primary cells and the cultured cells. The availability of well characterized and authenticated bona fide MM cell lines is of great importance for the study of the biology, etiology and treatment of the disease.
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Affiliation(s)
- Hans G Drexler
- DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany.
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62
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Ohbayashi K, Taniwaki M, Ninomiya M, Kiyoi H, Iida S, Ueda R, Naoe T. A xeno-transplantable plasma cell leukemia line with a split translocation of the IgH gene. CANCER GENETICS AND CYTOGENETICS 2003; 144:31-5. [PMID: 12810253 DOI: 10.1016/s0165-4608(02)00862-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A novel cell line, SACHI, was established from a pericardial effusion developed during the course of primary plasma cell leukemia (PCL). The cell line SACHI cells were the same as the infiltrating plasma cells with regard to surface markers (CD38(+)CD19(-)PCA-1(+)VLA-5(-)CD56(-)TdT(+)) and immunoglobulin gene rearrangements. Analysis of SACHI cells showed a complex hypertriploid (karyotype mode 70-73) including 7p32, 14q32, and Xq24 structural abnormalities, which were found also in the original leukemia cells. Dual-color fluorescence in situ hybridization revealed that the c-MYC gene was juxtaposed with a constant region of IgG (Cgamma) on 14q32. The split Cgamma locus was fused near the MAFB gene on chromosome 20. The SACHI cells had increased amounts of c-MYC and MAFB transcripts. Injection of SACHI cells into NOD/SCID mice generated leukemic plasmacytosis with invasion to liver, spleen, and bone marrow. This cell line may be useful for therapeutic testing as well as analyzing the molecular pathogenesis of PCL.
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Affiliation(s)
- Kaneyuki Ohbayashi
- Department of Infectious Diseases, Nagoya University School of Medicine, 466-8560, Nagoya, Japan
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63
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Firer MA, Laptev R, Kasatkin I, Trombka D. Specific destruction of hybridoma cells by antigen-toxin conjugates demonstrate an efficient strategy for targeted drug therapy in leukemias of the B cell lineage. Leuk Lymphoma 2003; 44:681-9. [PMID: 12769346 DOI: 10.1080/1042819031000063381] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Many types of leukemia including multiple myeloma remain essentially incurable despite recent developments in immuno- and chemotherapy. The effectiveness of these therapies might be greatly enhanced by targeting cell surface proteins unique to the malignant clone, which for leukemias of the B cell lineage means clonotypic surface immunoglobulin (sIg). As this immunoglobulin (Ig) is necessarily epitope specific, we are developing ligand-toxin conjugates (LTCs) as a strategy for delivering toxins and other drugs to clonotypic tumor cells. Here we report in vitro studies that illustrate the effectiveness of this approach. LTC comprising the DNP hapten conjugated to ricin A toxin (DNP-RTA) were shown to specifically and effectively kill anti-DNP secreting murine hybridoma (U7.6) cells but not other hybridoma cells (1B12), a murine erythroleukemia cell line (Friend's Leukemia or) normal mouse spleen cells. In addition to direct toxicity, LTC treatment negatively affected the growth characteristics of the few surviving cells as reflected in decreased growth index and an increase in growth inhibition over 72 h post treatment. Interestingly, U7.6 cells that survived one or two LD90 dose(s) of LTC showed no alteration in their dose response to a subsequent attack of LTC indicating that this treatment strategy may not induce drug resistance. These data suggest that LTC therapy may be a new and effective strategy for specific destruction of tumor cells such as myeloma plasma cells and could be extended to other tumors where clonotypic receptors can be identified.
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Affiliation(s)
- Michael A Firer
- Immunology Laboratory, Dept. Chemical Engineering and Biotechnology, College Judea and Samaria, P.O. Box 3, Ariel 44837 Israel.
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64
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Drexler HG, Dirks WG, Matsuo Y, MacLeod RAF. False leukemia-lymphoma cell lines: an update on over 500 cell lines. Leukemia 2003; 17:416-26. [PMID: 12592342 DOI: 10.1038/sj.leu.2402799] [Citation(s) in RCA: 145] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2002] [Accepted: 10/01/2002] [Indexed: 11/09/2022]
Abstract
Human leukemia-lymphoma (LL) cell lines represent an extremely important resource for research in a variety of fields and disciplines. As the cell lines are used as in vitro model systems in lieu of primary cell material, it is crucial that the cells in the culture flasks faithfully correspond to the purported objects of study. Obviously, proper authentication of cell line derivation and precise characterization are indispensable requirements to use as model systems. A number of studies has shown an unacceptable level of LL cell lines to be false. We present here the results of authenticating a comprehensively large sample (n = 550) of LL cell lines mainly by DNA fingerprinting and cytogenetic evaluation. Surprisingly, near-identical incidences (ca 15%) of false cell lines were observed among cell lines obtained directly from original investigators (59/395: 14.9%) and from secondary sources (23/155: 14.8%) implying that most cross-contamination is perpetrated by originators, presumably during establishment. By comparing our data with those published, we were further able to subclassify the false cell lines as (1) virtual: cross-contaminated with and unretrievably overgrown by other cell lines during initiation, never enjoying independent existence; (2) misidentified: cross-contaminated subsequent to establishment so that an original prototype may still exist; or (3) misclassified: unwittingly established from an unintended (often normal) cell type. Prolific classic leukemia cell lines were found to account for the majority of cross-contaminations, eg CCRF-CEM, HL-60, JURKAT, K-562 and U-937. We discuss the impact of cross-contaminations on scientific research, the reluctance of scientists to address the problem, and consider possible solutions. These findings provide a rationale for mandating the procurement of reputably sourced LL cell lines and their regular authentication thereafter.
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Affiliation(s)
- H G Drexler
- DSMZ-German Collection of Microorganisms and Cell Cultures, Department of Human and Animal Cell Cultures, Braunschweig, Germany
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65
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Abstract
Continuous human leukemia-lymphoma (LL) cell lines comprise a rich self-renewing resource of accessible and manipulable living cells which has illuminated the pathophysiology of hematopoietic tumors as well as basic cell biology. The major key advantages of continuous cell lines are the unlimited supply and worldwide availability of identical cell material and their cryopreservation. LL cell lines are characterized generally by monoclonal origin and differentiation arrest, sustained proliferation in vitro with preservation of most cellular features, and specific genetic alterations. The most practical classification of LL cell lines assigns them to one of the physiologically occurring cell lineages, based on their immunophenotype, genotype and functional features. Truly malignant cell lines may be distinguished from Epstein-Barr virus (EBV)-immortalized normal cells, using various operational and conceptual parameters. The characterization and publication of new LL cell lines provides important and informative core data which, by opening new avenues for investigation, have become ubiquitous powerful research tools that are available to every investigator by reference cell repositories. There is a need in the scientific community for clean and authenticated LL cell lines to which every scientist has access as offered by these institutionalized public cell line banks. A list of the most useful, robust and freely available reference cell lines is proposed in this review. Clearly, studies of LL cell lines have provided seminal insights into the biology of hematopoietic neoplasia.
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Affiliation(s)
- Hans G Drexler
- DSMZ-German Collection of Microorganisms and Cell Cultures, Department of Human and Animal Cell Cultures, Braunschweig, Germany.
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66
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Drexler HG, MacLeod RAF. Malignant hematopoietic cell lines: in vitro models for the study of mantle cell lymphoma. Leuk Res 2002; 26:781-7. [PMID: 12127550 DOI: 10.1016/s0145-2126(02)00026-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Mantle cell lymphoma (MCL) is a distinct type of B cell malignancy and accounts for approximately 5-10% of non-Hodgkin's lymphomas (NHL). The characteristic cytogenetic aberration in MCL is the translocation (11;14)(q13;q32) present in virtually all cases. This rearrangement at the BCL1 locus at 11q13 dysregulates the gene CCND1 following juxtaposition with immunoglobulin heavy chain (IGH) transcriptional enhancers at 14q32 and leading to overexpression of its protein product, cyclin D1, which plays a key role in the control of the cell cycle. Eight continuous cell lines (plus several sister cell lines) have been hitherto established from lymph nodes or peripheral blood of patients with MCL (n=5) or with a lymphoma which would nowadays be classified as MCL (n=3). Six of these cell lines carry the specific t(11;14) translocation and a seventh cell line while being negative for t(11;14) shows a rearranged BCL1 locus and cyclin D1 overexpression. Each of these MCL cell lines is unique with regard to its immunophenotypical, additional cytogenetic and functional features. In light of the relatively low frequency of this lymphoma and the poor results of current treatment strategies, the availability of various types of MCL-derived cell lines for immunologic, cytogenetic, molecular and functional studies is expected to illuminate the biology of this disease, which in turn will be hopefully translated into new and better therapies.
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Affiliation(s)
- Hans G Drexler
- DSMZ-German Collection of Microorganisms & Cell Cultures, Department of Human and Animal Cell Cultures, Mascheroder Weg 1 B, Braunschweig, Germany.
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67
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Lai R, McDonnell TJ, O'Connor SL, Medeiros LJ, Oudat R, Keating M, Morgan MB, Curiel TJ, Ford RJ. Establishment and characterization of a new mantle cell lymphoma cell line, Mino. Leuk Res 2002; 26:849-55. [PMID: 12127561 DOI: 10.1016/s0145-2126(02)00013-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Mantle cell lymphoma (MCL) is a distinct type of B-cell non-Hodgkin's lymphoma characterized by cyclin D1 overexpression and the cytogenetic abnormality, the t(11;14)(q13;q32). MCL cell lines have been difficult to establish and in vitro studies of these neoplasms are scarce. We describe the establishment and characteristics of a new MCL cell line, Mino. The cells are large, growing singly and in small clumps in vitro. By flow cytometry, the immunophenotype was compatible with MCL (i.e. CD5+CD20+CD23-FMC7+). Conventional cytogenetics showed hyperdiploidy with multiple complex karyotypic abnormalities, but no evidence of the t(11;14), proven to be present only by fluorescence in situ hybridization and polymerase chain reaction (PCR) methods. Western blots showed expression of cyclin D1 but no detectable cyclin D2 and cyclin D3; the retinoblastoma protein was predominantly phosphorylated. There was expression of tumor suppressor gene products including p53, p16(INK4a), and p21(WAF1). Sequencing of the TP53 gene revealed a mutation (codon 147(valine-->glycine)) in exon 5. Epstein Barr virus was absent. In summary, Mino is a new MCL cell line that may be useful to study the pathogenesis of MCL.
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MESH Headings
- Amino Acid Substitution
- Aneuploidy
- Antigens, CD/analysis
- Blotting, Western
- Cell Cycle Proteins/analysis
- Cell Size
- Chromosome Aberrations
- Codon/genetics
- Cyclins/analysis
- Exons/genetics
- Fatal Outcome
- Female
- Genes, p53
- Herpesvirus 4, Human
- Humans
- Immunophenotyping
- In Situ Hybridization, Fluorescence
- Karyotyping
- Lymphoma, Mantle-Cell/chemistry
- Lymphoma, Mantle-Cell/genetics
- Lymphoma, Mantle-Cell/pathology
- Middle Aged
- Mutation, Missense
- Neoplasm Proteins/analysis
- Point Mutation
- Polymerase Chain Reaction
- Tumor Cells, Cultured/chemistry
- Tumor Cells, Cultured/pathology
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Affiliation(s)
- R Lai
- Department of Hematopathology, University of Texas, M.D. Anderson Cancer Center, 1515 Holcombe Blvd., Box 72, Houston, TX 77030, USA.
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68
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Abstract
Human leukemia-lymphoma (LL) cell lines represent important tools for experimental research. Among the various problems associated with cell lines, the two most common concern contaminations: (1) cross-contamination with unrelated cells and (2) contamination with microorganisms, in particular mycoplasma. The bad news is that about one-third of the cell lines are either cross-contaminated or mycoplasma-infected or both. The good news is that there are means to recognize and overcome these problems. In cases where, during attempts to establish new LL cell lines, primary LL cultures are cross-contaminated with continuous cell lines, intended new cell lines simply cannot be established ("early" cross-contamination). In cases of "late" cross-contamination of existing LL cell lines where the intrusive cells have a growth advantage, the original ("uncontaminated") cell lines may still be available elsewhere. DNA fingerprinting and cytogenetic analysis appear to be the most suitable approaches to detect cross-contaminations and to authenticate LL cell lines. A different but related aspect of "false" LL cell lines is the frequent misclassification of cell lines whereby the actual cell type of the cell line does not correspond to the purported model character of the cell line. Mycoplasma infection can have a multitude of effects on the eukaryotic cells which, due to the variety of infecting mycoplasma species and many other contributing parameters, cannot be predicted, rendering resulting data questionable at best. Practical procedures for the detection and elimination of mycoplasma contamination have been developed. Diagnostic and preventive strategies in order to hem the alarming increase in "false" and mycoplasma-positive LL cell lines are recommended.
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69
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Avet-Loiseau H, Facon T, Grosbois B, Magrangeas F, Rapp MJ, Harousseau JL, Minvielle S, Bataille R. Oncogenesis of multiple myeloma: 14q32 and 13q chromosomal abnormalities are not randomly distributed, but correlate with natural history, immunological features, and clinical presentation. Blood 2002; 99:2185-91. [PMID: 11877296 DOI: 10.1182/blood.v99.6.2185] [Citation(s) in RCA: 264] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Multiple myeloma (MM) is a plasma-cell malignancy characterized by marked epidemiological, biological, and clinical heterogeneity. The goal of this study was to find a genetic basis for this heterogeneity. Using fluorescence in situ hybridization, we analyzed a prospective cohort of 901 patients with various plasma-cell disorders--monoclonal gammopathies of undetermined significance, smoldering MM, MM, and primary plasma-cell leukemia--for genetic abnormalities involving the 13q14 and 14q32 chromosomal regions; the patients were consecutively enrolled in the Intergroupe Francophone du Myélome clinical trials, We performed statistical analyses comparing these chromosomal abnormalities in terms of immunological (ie, immunoglobulin types and light-chain subtypes) and clinical status and, to some extent, prognostic features. It was found that 14q32 translocations and del(13) are the most frequent chromosomal abnormalities, observed in 75% and 45% of the patients, respectively, and are not randomly distributed, but interconnected. Second, correlations between them allowed us to define 4 major genetic categories of patients: (1) patients lacking any 14q32 abnormality (25%) and generally also lacking del(13); (2) patients presenting either t(4;14) or t(14;16), almost always associated with a del(13) (15% of patients); (3) patients with other 14q32 abnormalities and presenting del(13) (25%); and (4) patients with other 14q32 abnormalities but not presenting del(13) (35%). Third, we show that this genetic stratification is highly correlated with immunological status and clinical presentation and with some major prognostic factors. For the first time, this study gives genetic support to the heterogeneity observed in patients with MM and demonstrates that the 14q32 and 13q chromosomal abnormalities are not randomly distributed. The strong correlations we found might be the basis for a novel genetic classification of MM, as has been previously demonstrated for leukemias and lymphomas. Furthermore, our study supports different models for MM oncogenesis.
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Affiliation(s)
- Hervé Avet-Loiseau
- Laboratory and Clinical Department of Hematology, University Hospital, 9 quai Moncousu, 44093 Nantes, France.
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70
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Abstract
Multiple myeloma is a neoplasm of terminally differentiated B cells (plasma cells) in which chromosome translocations frequently place oncogenes under the control of immunoglobulin enhancers. Unlike most haematopoietic cancers, multiple myeloma often has complex chromosomal abnormalities that are reminiscent of epithelial tumours. What causes full-blown myeloma? And can our molecular understanding of this common haematological malignancy be used to develop effective preventive and treatment strategies?
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Affiliation(s)
- W Michael Kuehl
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda Naval Hospital, Maryland 20889-5105, USA.
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71
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Drexler HG, Matsuo Y. Commentary: what is an 'NK-precursor cell line'? Leuk Res 2002; 26:297-9. [PMID: 11792419 DOI: 10.1016/s0145-2126(01)00116-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Hans G Drexler
- DSMZ -- German Collection of Microorganisms and Cell Cultures, Department of Human and Animal Cell Cultures, Mascheroder Weg 1B, 38124 Braunschweig, Germany.
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72
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Ueda C, Yamada H, Akasaka T, Ohmori K, Sasada M, Uchiyama T, Ohno H. Establishment and characterization of a new human myeloma cell line, KYdelta-1, producing the delta/kappa type immunoglobulin. CANCER GENETICS AND CYTOGENETICS 2001; 130:42-50. [PMID: 11672773 DOI: 10.1016/s0165-4608(01)00467-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
We describe the establishment and characterization of a new multiple myeloma (MM) cell line, KYdelta-1, which expressed delta/kappa type immunoglobulin (Ig). The patient was a 65-year-old woman with MM, who presented extramedullary dissemination, lymphadenopathy and short survival. The KYdelta-1 cell line was derived from the pleural fluid obtained in the terminal phase of the disease. The cells expressed delta/kappa Ig in the cytoplasm, and CD10, CD29, CD33, CD38, CD44, CD54, and HLA-DR antigens on the cell surface. Chromosomal analysis revealed two independent translocations, t(3;14)(p21;q32) and t(3;11)(p21;q13), which were confirmed by fluorescence in situ hybridization using chromosome painting probes. Reverse transcriptase-mediated polymerase chain reaction (PCR) and Northern blot analyses demonstrated overexpression of the CCND1 gene, suggesting alteration of the BCL1-CCND1 locus. We thus performed long-distance inverse PCR using nested primers for the Calpha constant region of immunoglobulin heavy chain gene (IGH) and obtained a clone that encompassed the 11q13/IGH fusion. Nucleotide sequencing determined that the fusion occurred at the Salpha2 switch region and at the centromeric side of the major translocation cluster of BCL1. The other IGH allele consisted of a VDJ complex that was adjacent to the Cdelta constant gene, indicating that a class switch-like mechanism from the C(mu) to Cdelta was involved in the production of the Ig delta heavy chain. Point mutations within the P53 and N-RAS genes were presumably related to the rapidly progressive disease in this particular MM patient.
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MESH Headings
- Aged
- Base Sequence
- Blotting, Northern
- Blotting, Southern
- Chromosomes, Human, Pair 14
- Chromosomes, Human, Pair 3
- Cloning, Molecular
- DNA, Neoplasm
- Female
- Genes, p53
- Genes, ras
- Humans
- Immunoglobulin Heavy Chains/genetics
- Immunoglobulin Heavy Chains/immunology
- In Situ Hybridization, Fluorescence
- Karyotyping
- Molecular Sequence Data
- Multiple Myeloma/genetics
- Multiple Myeloma/immunology
- Multiple Myeloma/pathology
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Homology, Nucleic Acid
- Translocation, Genetic
- Tumor Cells, Cultured
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Affiliation(s)
- C Ueda
- First Division, Department of Internal Medicine, Faculty of Medicine, Kyoto University, 54-Shogoin-Kawaramachi, 606-8507, Sakyo-ku, Kyoto, Japan
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73
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Otsuki T, Wada H, Nakazawa N, Taniwaki M, Kouguchi K, Ohkura M, Uehira K, Isoda K, Yata K, Sakaguchi H, Yawata Y, Ueki A, Yamada O. Establishment of CD7+ human myeloma sister cell lines, KMS-21-PE and KMS-21-BM, carrying t(11;14) and t(8;14). Leuk Lymphoma 2001; 42:761-74. [PMID: 11697507 DOI: 10.3109/10428190109099339] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Two new human myeloma cell lines were established from pleural effusion and bone marrow malignant cells derived from a single patient, who manifested hyperammonemia associated with multiple myeloma, and these were characterized. Both lines possess t(11;14)(q13;q32) and t(8;14)(q24;q32) reciprocal translocations and overexpress cyclin D1, but not c-myc. Human myeloma lines including these new lines produced and secreted excess ammonia into culture medium more than non-myelomatous hematological cell lines. In addition, these two lines were revealed to have high surface CD7 expression correlated with relatively high mRNA expression by MP-RT-PCR. Among 8 human myeloma lines, half of them revealed significant surface expression of CD7 and a positive correlation between expression levels of protein and message. CD7 message was also detected in surface negative lines. Consequently, there may be posttranslational regulation of the CD7 molecule, whose cellular biological role in expressing cells has not been elucidated.
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MESH Headings
- Adult
- Ammonia/metabolism
- Antigens, CD7/metabolism
- Bone Marrow Cells/pathology
- Chromosomes, Human, Pair 11
- Chromosomes, Human, Pair 14
- Chromosomes, Human, Pair 8
- Cyclin D1/metabolism
- Humans
- Hyperammonemia/etiology
- Hyperammonemia/pathology
- Male
- Multiple Myeloma/complications
- Multiple Myeloma/genetics
- Multiple Myeloma/pathology
- Pleural Effusion, Malignant/pathology
- Proto-Oncogene Proteins c-myc/metabolism
- Translocation, Genetic
- Tumor Cells, Cultured/cytology
- Tumor Cells, Cultured/immunology
- Tumor Cells, Cultured/metabolism
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Affiliation(s)
- T Otsuki
- Department of Hygiene, Kawasaki Medical School, Kurashiki, Okayama, Japan.
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74
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Shapiro VS, Mollenauer MN, Weiss A. Endogenous CD28 expressed on myeloma cells up-regulates interleukin-8 production: implications for multiple myeloma progression. Blood 2001; 98:187-93. [PMID: 11418479 DOI: 10.1182/blood.v98.1.187] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
CD28 is the major costimulatory molecule on T cells. CD28 activation, in conjunction with T-cell receptor engagement, up-regulates transcription of several cytokines, including interleukin-2 (IL-2), through transcriptional activation of the RE/AP composite element. Although CD28 is not normally expressed on B cells or plasma cells, more than 90% of extramedullary myelomas (a late stage B-cell neoplasm) express CD28. The functional significance of this is unknown. The results of this study demonstrate that CD28 stimulates transcriptional activation of RE/AP-based reporters in B cells and myeloma cells. However, CD28 stimulation does not up-regulate IL-2 production in myeloma cell lines, demonstrating that the IL-2 promoter may not be a relevant RE/AP-containing target of CD28 in myelomas. Instead, an RE/AP composite element has been identified within the promoter of the IL-8 gene, a chemokine that promotes angiogenesis. Furthermore, stimulation of endogenous CD28 expressed by 3 myeloma cell lines increased IL-8 production. Therefore, the study demonstrates that CD28 is functional in myelomas to up-regulate transcription of endogenous genes, including IL-8. The proposal is made that aberrant expression of CD28 may play a role in the progression of multiple myeloma.
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Affiliation(s)
- V S Shapiro
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, USA
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75
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Drexler HG, Matsuo AY, MacLeod RA. Continuous hematopoietic cell lines as model systems for leukemia-lymphoma research. Leuk Res 2000; 24:881-911. [PMID: 11086173 DOI: 10.1016/s0145-2126(00)00070-9] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Along with other improvements, the advent of continuous human leukemia-lymphoma (LL) cell lines as a rich resource of abundant, accessible and manipulable living cells has contributed significantly to a better understanding of the pathophysiology of hematopoietic tumors. The first LL cell lines, Burkitt's lymphoma-derived lines, were established in 1963. Since then, more than 1000 cell lines have been described, although not all of them in full detail. The major advantages of continuous cell lines is the unlimited supply and worldwide availability of identical cell material, and the infinite viable storability in liquid nitrogen. LL cell lines are characterized generally by monoclonal origin and differentiation arrest, sustained proliferation in vitro under preservation of most cellular features, and specific genetic alterations. The most practical classification of LL cell lines assigns them to one of the physiologically occurring cell lineages, based on their immunophenotype, genotype and functional features. Truly malignant cell lines must be discerned from Epstein-Barr virus (EBV)-immortalized normal cells, using various distinguishing parameters. However, the picture is not quite so straightforward, as some types of LL cell lines are indeed EBV+, and some EBV+ normal cell lines carry also genetic aberrations and may mimic malignancy-associated features. Apart from EBV and human T-cell leukemia virus in some lines, the majority of wild-type LL cell lines are virus-negative. The efficiency of cell line establishment is rather low and the deliberate establishment of new LL cell lines remains by and large an unpredictable random process. Difficulties in establishing continuous cell lines may be caused by the inappropriate selection of nutrients and growth factors for these cells. Clearly, a generally suitable microenvironment for hematopoietic cells, either malignant or normal, cannot yet be created in vitro. The characterization and publication of new LL cell lines should provide important and informative core data, attesting to their scientific significance. Large percentages of LL cell lines are contaminated with mycoplasma (about 30%) or are cross-contaminated with other cell lines (about 15-20%). Solutions to these problems are sensitive detection, effective elimination and rigorous prevention of mycoplasma infection, and proper, regular authentication of cell lines. The underlying cause, however, appears to be negligent cell culture practice. The willingness of investigators to make their LL cell lines available to others is all too often limited. There is a need in the scientific community for clean and authenticated high-quality LL cell lines to which every scientist has access. These are offered by various institutionalized public cell line banks. It has been argued that LL cell lines are genetically unstable (both cytogenetically and molecular genetically). For instance, cell lines are supposed to acquire numerical and structural chromosomal alterations and various types of mutations (e.g. point mutations) in vitro. We present evidence that while nearly 100% of all LL cell lines indeed carry genetic alterations, these alterations appear to be stable rather than unstable. As an example of the practical utility of LL cell lines, the recent advances in studies of classical and molecular cytogenetics, which in large part were made possible by cell lines, are highlighted. A list of the most useful, robust and publicly available reference cell lines that may be used for a variety of experimental purposes is proposed. Clearly, by opening new avenues for investigation, studies of LL cell lines have provided seminal insights into the biology of hematopoietic neoplasia. Over a period of nearly four decades, these initially rather exotic cell cultures, known only to a few specialists, have become ubiquitous powerful research tools that are available to every investigator.
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Affiliation(s)
- H G Drexler
- DSMZ-German Collection of Microorganisms and Cell Cultures, Department of Human and Animal Cell Cultures, Braunschweig, Germany.
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