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  • 1
    In: Gastroenterology, Elsevier BV, Vol. 138, No. 5 ( 2010-5), p. S-500-
    Type of Medium: Online Resource
    ISSN: 0016-5085
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    Language: English
    Publisher: Elsevier BV
    Publication Date: 2010
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  • 2
    In: Blood, American Society of Hematology, Vol. 114, No. 22 ( 2009-11-20), p. 1105-1105
    Abstract: Abstract 1105 Poster Board I-127 Genetic recombination plays a critical role in telomere maintenance, chromosomal translocation, and gene amplification, and may therefore underlie the chromosomal aberrations observed with high frequency in number of malignancies. The molecular mechanism/s inducing genomic instability remains ill-defined and their elucidation may provide methods to prevent tumor progression and development of drug resistance. Our earlier work has demonstrated that homologous recombination (HR) activity is elevated in multiple myeloma (MM) cells and leads to increased rate of mutation and progressive accumulation of genetic variation over time. We have further demonstrated that the inhibition of HR activity in MM cells by siRNAs targeting recombinase leads to significant reduction in the acquisition of new genetic changes in the genome; and conversely, induction of HR activity leads to significant elevation in the number of new mutations over time, and development of drug resistance in MM cells. Here we have evaluated a PI3K inhibitor Wortmaninin which has significant inhibitory activity against both HR and non-HR (nHR) pathways. Exposure of MM cells (OPM1, ARP and RPMI 8226) to wortmannin (WM) led to reduced expression of recombinase (hsRAD51) and nearly complete inhibition of HR activity, within 24 hrs as determined by a plasmid based assay in which generation of active gene product by recombination is measured. Similarly nHR was evaluated by measuring generation of intact gene product from a linearized plasmid. We evaluated effect of WM on nHR by 3 hours preincubation before transfecting the plasmid followed by cell culture for 72 hrs at 37° C. Cells were harvested and analyzed for nHR as previously described. Treatment with WM led to 〉 40% reduction in nHR, indicating that WM affects both HR and NHR pathways. Downregulation of these pathways by wortmannin was also associated with a reduced growth rate of myeloma cells in culture by 20-25% at 48 hours. Importantly, WM treatment markedly decreased the acquisition of new genomic changes in MM as measured by genome-wide loss of heterozygosity assay as an indicator of genomic stability. To evaluate the impact of WM on in vivo tumor growth, OPM1 cells were injected subcutaneously in SCID mice and following appearance of palpable tumors, mice were treated with WM at 0.75 mg/kg, injecting daily intraperitoneally. Treatment with WM was associated with almost complete inhibition of tumor growth in vivo. Long term exposure of myeloma cells to WM was consistently associated with reduced telomere length, probably by blocking HR dependent ALT pathway. These data identifies dysregulated recombination activity as a key mediator of DNA instability and progression of MM, and WM as a potential therapeutic agent for prevention of myeloma progression and possibly drug resistance. Disclosures Anderson: Millenium: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding. Munshi:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Millennium: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis : Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2009
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 3
    In: Blood, American Society of Hematology, Vol. 114, No. 22 ( 2009-11-20), p. 1841-1841
    Abstract: Abstract 1841 Poster Board I-867 Sp1 is a transcription factor with an important role in regulating expression of cell cycle, cell differentiation and apoptosis related genes containing proximal GC/GT-rich promoter elements. It affects growth and metastatic potential of tumor cells. In multiple myeloma (MM), key growth and survival genes such as NF-kB p65, IGF-IR, VEGF, and IL-6 contains proximal GC-rich promoter sequences that interact with Sp proteins to control their expression. Based on this we have evaluated role of Sp1 in MM. We have observed high Sp1 expression along with increased Sp1 activity in MM cells compared to normal peripheral blood mononuclear cells. We have confirmed, by immunohistochemistry, higher nuclear localization of Sp1 in MM cells compared to other normal elements in bone marrow biopsy specimens. Moreover, we have also observed further induction of Sp1 activity shama(≥2 fold increase) after adhesion to BMSC. We next evaluated Sp1 function by analyzing the effect of Sp1 knock down in MM. Interference of Sp1 activity using siRNA showed inhibition of MM cell proliferation (≥75% inhibition) induction of apoptosis and G1 arrest. We have also used three lentiviral shRNA constructs confirming similar effects of Sp1 knock down on MM cells. We have further investigated effects of Sp1 inhibitor Terameprocol on MM cells. Terameprocol is clinical applicable small molecule that specifically competes with Sp1 for specific DNA binding domains within promoter regions. Terameprocol significantly inhibited MM cell growth in a dose-dependent fashion (IC50 beetween 5–20 μM at 24 hours) and was able to overcome the protective effects of BMSCs, inducing apoptosis, via induction of caspases activation and reduction in survivin expression at both gene and protein levels. Based on the data suggesting that both dexamethasone and Velcade increase Sp1 activity, we have combined Terameprocol with these agents and observed synergistic activity. Finally, Terameprocol treatment of nude mice bearing human myeloma xenograft resulted in tumor regression by triggering apoptosis and improving survival of mice. In conclusion, our results confirm significant biological role of Sp1 transcription factor in myeloma that can be therapeutically targeted for clinical development. Disclosures: Mohrland: Erimos Pharmaceuticals: Employment.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2009
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 4
    In: Blood, American Society of Hematology, Vol. 115, No. 26 ( 2010-07-01), p. 5385-5392
    Abstract: Elevated cytokines in bone marrow (BM) micro-environment (interleukin-6 [IL-6], transforming growth factor-beta [TGF-β] , and IL-1β) may play an important role in observed immune dysfunction in multiple myeloma (MM). As IL-6 and TGF-β are important for the generation of T-helper 17 (TH17) cells, we evaluated and observed a significantly elevated baseline and induced frequency of Th17 cells in peripheral blood mononuclear cells (PBMCs) and BM mononuclear cells (BMMCs) from MM patients compared with healthy donors. We observed significant increase in levels of serum IL-17, IL-21, IL-22, and IL-23 in blood and BM in MM compared with healthy donors. We also observed that myeloma PBMCs after TH17 polarization significantly induced IL-1α, IL-13, IL-17, and IL-23 production compared with healthy donor PBMCs. We next observed that IL-17 promotes myeloma cell growth and colony formation via IL-17 receptor, adhesion to bone marrow stromal cells (BMSCs) as well as increased growth in vivo in murine xenograft model of human MM. Additionally, we have observed that combination of IL-17 and IL-22 significantly inhibited the production of TH1-mediated cytokines, including interferon-γ (IFN-γ), by healthy donor PBMCs. In conclusion, IL-17–producing Th17 cells play an important role in MM pathobiology and may be an important therapeutic target for anti-MM activity and to improve immune function.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2010
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 5
    In: Blood, American Society of Hematology, Vol. 112, No. 11 ( 2008-11-16), p. 2741-2741
    Abstract: Stathmin(Op18) is a ubiquitous cytosolic 18Kda protein regulating microtubule (MT) dynamics via binding and stabilizing activities. The activity of Op18 is down regulated during cell cycle by phosphorylation at four Ser residues. The phospho-Op18 is unable to bind to tubulin allowing the progression of the cell cycle. Two additional Op18-binding proteins, KIS prevents Op18 dephosphorylation and activation while iASPP (inhibitor of apoptosis stimulatory protein phosphatase) binds to WT-p53 and inhibits p53-related apoptosis. We have identidfied Op18 as a differentially expressed gene by suppression subtractive hybridization in myeloma. We have also confirmed differential expression of KIS in myeloma cells compared to normal plasma cells. Overexpression of Op18 was confirmed at both RNA and at protein level by RT –PCR and Western blotting in human myeloma cell lines as well as primary samples compared to normal plasma cells and normal human fibroblasts. In contrast, none of the tonsillar CD138+ plasma cells and normal bone marrow mononuclear cells showed Op18 overexpression. To establish the role of Op18 overexpression in MM cell transformation, the human MM cell lines were treated with antisense Op18 oligodeoxynucleotides (ODN). The growth rate of the ODN treated human myeloma cells was significantly reduced compared to the control cells along with cell cycle arrest in G2/M phase and increase in apoptosis as measured by immunohistochemical staining. Additionally, we have silenced Op18 by transfecting Op18-specific siRNA in MM cells and observed that KIS is translocated to cytoplasm, from nucleus as well as MM cells are arrested in G2/M. Importantly, Op18 silencing increased sensitivity of MM cells to microtubule drugs suggesting possible combination approach for therapeutic application. Its role in networking cellular signal transduction pathways in myeloma is under investigation. Recent publication identifying Op18 as one of the 15 most relevant genes determining outcome in myeloma (Avet-loiseau et al, JCO 2008) adds to the validity of Op18 as a molecule playing important role in myeloma cell growth and survival and warrant investigation as a novel therapeutic target.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2008
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 6
    Online Resource
    Online Resource
    Wiley ; 2016
    In:  European Journal of Neuroscience Vol. 43, No. 10 ( 2016-05), p. 1298-1306
    In: European Journal of Neuroscience, Wiley, Vol. 43, No. 10 ( 2016-05), p. 1298-1306
    Abstract: A distributed network of neurons regulates wake, non‐rapid eye movement ( NREM ) sleep, and REM sleep. However, there are also glia in the brain, and there is growing evidence that neurons and astroglia communicate intimately to regulate behaviour. To identify the effect of optogenetic stimulation of astrocytes on sleep, the promoter for the astrocyte‐specific cytoskeletal protein, glial fibrillary acidic protein ( GFAP ) was used to direct the expression of channelrhodopsin‐2 (ChR2) and the linked reporter gene, enhanced yellow fluorescent protein ( EYFP ), in astrocytes. rAAV ‐ GFAP ‐ChR2 (H134R)‐ EYFP or rAAV ‐ GFAP ‐ EYFP was microinjected (750  nL ) into the posterior hypothalamus (bilateral) of mice. Three weeks later baseline sleep was recorded (0 Hz) and 24 h later optogenetic stimulation applied during the first 6 h of the lights‐off period. Mice with ChR2 were given 5, 10 or 30 Hz stimulation for 6 h (10‐ms pulses; 1  mW ; 1 min on 4 min off). At least 36 h elapsed between the stimulation periods (5, 10, 30 Hz) and although 0 Hz was always first, the order of the other three stimulation rates was randomised. In mice with ChR2 ( n  = 7), 10 Hz, but not 5 or 30 Hz stimulation increased both NREM and REM sleep during the 6‐h period of stimulation. Delta power did not increase. In control mice (no ChR2; n  = 5), 10 Hz stimulation had no effect. This study demonstrates that direct stimulation of astrocytes powerfully induces sleep during the active phase of the sleep–wake cycle and underlines the inclusion of astrocytes in network models of sleep–wake regulation.
    Type of Medium: Online Resource
    ISSN: 0953-816X , 1460-9568
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2016
    detail.hit.zdb_id: 2005178-5
    SSG: 12
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  • 7
    Online Resource
    Online Resource
    Frontiers Media SA ; 2015
    In:  Frontiers in Systems Neuroscience Vol. 8 ( 2015-01-08)
    In: Frontiers in Systems Neuroscience, Frontiers Media SA, Vol. 8 ( 2015-01-08)
    Type of Medium: Online Resource
    ISSN: 1662-5137
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2015
    detail.hit.zdb_id: 2453005-0
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  • 8
    In: Blood, American Society of Hematology, Vol. 112, No. 11 ( 2008-11-16), p. 2737-2737
    Abstract: TH17 cells are T helper cells generated from naïve CD4 population in the presence of TGF-beta and IL-6 or IL-1-beta; and expanded in presence of IL-23. TH17 cells predominantly produce IL-17 and/or IL-22 and participate in both development of immunity and autoimmunity. Since TH17 cells are involved in modulation of immune response and we haveobserved both B and T cell immune dysfunction in multiple myeloma (MM), we have further evaluated the role of TH17 cells and associated cytokines in tumor cell growth, as well as, the imbalance of immune homeostasis in myeloma. We first observed that the baseline frequency of TH17 cells was significantly higher in mononuclear cells from MM patient peripheral blood (n=11) (2 folds) and bone marrow (n=4) (50%) compared to normal donor samples. Furthermore, under polarizing conditions with cytokine cocktail, significantly higher number of TH17 cells were induced in presence of TGF-beta in mononuclear cells from MM patients in both blood (4 fold) and bone-marrow (9 fold) compared to normal donor samples. These results indicate that the cytokines present in the BM microenvironment favor the development of TH17 cell subset. We next evaluated the serum levels of TH17-associated cytokines in sera from patients with MM, as well as, normal donors. We observed significant increase in levels of IL-17 (2 fold), IL-21 (5 fold), IL-22 (8 fold) and IL-23 (6 fold) in myeloma (n=17) compared with normal donor (n=6). Importantly, IL-23 levels were 10 fold higher in myeloma BM samples compared with matching blood samples. Next, we evaluated the effect of TH17-associated pro-inflammatory cytokines on MM cell growth and survival. We observed induction of proliferation of 6 MM cell lines, as measured by thymidine incorporation, by IL-17 (30%), IL-21 (35%) and IL-22 (25%). Additionally, IL-17 significantly induced growth of MM cells in clonogenic assay. These growth promoting effects are not observed in the presence of anti-IL-17 antibody. In an effort to evaluate the cellular basis for this growth promoting effect of these cytokines, we investigated production of MM growth promoting cytokines in the BM milieu. We observed induction of IL-6 production by IL-17 from BM stromal cells alone and in the presence of MM cells. Production of IL-6 induced by IL-17 was abrogated (40–50%) by transduction of siRNA targeting IRF-4 into co-culture components (stromal and myeloma cells). The inhibition of IL-17-induced IL-6 production in stromal cells was also observed with JAK-2 (70%) and MEK (76%) inhibitors suggesting role of multiple signalling pathways in induction of IL-6. Finally, we have also observed negative effects of TH17- related cytokines, especially IL-17 and IL-22, on development of IFN-gamma producing TH1 cells suggesting immunosuppressive effect. Taken together these results suggest significant role of IL-17 and related cytokines in myeloma cell growth, as well as, immune dysfunction observed in these patients. This data provides the preclinical rationale to target IL-17 in myeloma to suppress growth as well as improve immune responsiveness.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2008
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 9
    In: Blood, American Society of Hematology, Vol. 110, No. 11 ( 2007-11-16), p. 3517-3517
    Abstract: Multiple myeloma (MM) is associated with significant immune dysfunction. Although various mechanisms mediating immune dysregulation in MM have been studied, its molecular and cellular basis is ill defined. IL-6, TGF-β and IL-1β have been implicated in this process, but their mechanism of effects on immune function have not been studied in MM. Together, IL-6 and TGF-β enhance the generation of TH17 cells, important in the development of immunity and auto-immunity. Additionally, TH17 cells are differentiated by number of inflammatory cytokines including, IL-21, IL-22, IL-23, and IL-27. Therefore, we evaluated the immune dysfunction and the role of TH17 cells and associated pro-inflammatory cytokines in myeloma. We have previously characterized that the production of TH1 mediated cytokines including IFN-γ following anti-CD3-mediated activation is significantly lower in myeloma PBMC compared to normal PBMC. We hypothesize that this may be regulated via skewing the immune system towards TH17 pathway. We observed that TH17 cells, measured by intra-cellular flow cytometry, are significantly increased in number in myeloma (16.9%) and MGUS (6.2%) compared to normal (3.3%). Furthermore, we analysed supporting pro-inflammatory cytokine network for the generation of TH17 cells in myeloma, which may be responsible for the observed TH17 skewing of T cell subsets. Sera from MGUS (n=12) and myeloma (n=17) patients were evaluated for the presence of these pro-inflammatory cytokines compared with normal sera (n=6) using ELISA. We observed significant increase in serum IL-21, IL-22 and IL-23 in MGUS (373 pg/ml, 14 pg/ml and 147 pg/ml respectively; p 〈 0.05) and myeloma (296 pg/ml, 12 pg/ml and 215 pg/ml respectively; p 〈 0.05) compared with normal (63 pg/ml, 1.5 pg/ml and 39 pg/ml respectively). In addition, we also observed that the myeloma PBMC stimulated in the presence of IL-6 and TGF-β, both of the cytokines present at a high level in myeloma, induced significant IL-23 production compared with normal. Importantly, IL-23 levels were 10 fold higher in myeloma BM samples compared with matching blood samples. These results indicate that the cytokines from myeloma BM microenvironment may be responsible for the observed T cell subset abnormality by favouring TH17 cells via IL-23/IL-21 production. These cytokines thus may be targets to modulate immune responses in myeloma to enhance immune function and devise effective vaccination strategies in the future.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2007
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 10
    In: Blood, American Society of Hematology, Vol. 116, No. 21 ( 2010-11-19), p. 446-446
    Abstract: Abstract 446 Waldenstrom's macroglobulinemia (WM), similar to multiple myeloma (MM), is associated with immune dysfunction. Both T and B cell dysfunctions are reported with suppressed uninvolved immunoglobulin, and inadequate vaccine and T cell responses. Although some mechanisms mediating immune dysregulation in WM have been studied, its molecular and cellular basis remains ill defined. Similarly, number of inflammatory cytokines and chemokines has been implicated in this process, but their effect on WM cell growth and immune function has not been well characterized. Recently, TH17 cells, a new CD4 cell population, has been identified by the presence of IL-17. TH17 cells play an important role in auto-immunity and in the development of anti-tumor immunity. As TH17 cells support MM cell growth and induce immune dysfunction in MM, we have evaluated the the role of TH17 cells and associated pro-inflammatory cytokines in WM. We first analyzed T helper cell subsets (TH1, TH2, and TH17) in freshly isolated PBMC from WM, and observed that all three cell types were decreased in WM compared with normal donors. Particularly, the IFN-γ producing TH1 cells from patients with WM were significantly reduced compared to normal donors (11±2% vs 30±3% respectively, P 〈 0.01). However, unlike MM, IL-17 producing TH17 cell numbers were reduced in PBMC from WM patients (n=8) compared to PBMC from normal donors (n=8) and patients with MM (n=11), (1.5±0.5 vs 2.5±0.5% vs 4.50±0.8% respectively; p 〈 0.05). Furthermore, when we polarized isolated naïve CD4 cells from WM patients using TH17 polarizing cocktail consisting of IL-6, IL-1β, IL-23 and TGF-β to induce TH17 cells differentiation, WM patients, unlike MM patients, showed significantly lower induction of TH17 cells in CD4 population compared to normal donor TH17 cells (0.3±0.1% WM; 11.9±2 % MM and 3.6±0.7% ND). Next, we evaluated the serum levels of cytokines and chemokines in sera from patients with WM in comparison with normal donors. The sera from WM patients showed significantly elevated levels of IL-2 (5 folds), IL-15 (2 folds) and GM-CSF (2 folds) among 19 cytokines, compared with sera from normal donors. When we evaluated TH17 cell-associated cytokines, both IL-1-beta (3 folds) and IL-17 (2 folds) were significantly elevated in sera from WM patients compared with sera from normal donors. In addition, we observed modulation of chemokines including, MCP-1, MIP-1, Eotaxin and RANTES in sera from WM patients. Finally, when we cultured WM cell-line in the presence or absence of IL-17 with or without stromal cells, we observed significant induction of WM cell proliferation by IL-17 and its inhibition by anti-IL17 antibody. These data shows that although similar to MM, there is immune dysfunction in WM, the mechanisms driving these effects especially cytokine milieu, and TH17 cell population are different between MM and WM. Disclosures: Treon: Millennium Pharmaceuticals, Genentech BiOncology, Biogen IDEC, Celgene, Novartis, Cephalon: Consultancy, Honoraria, Research Funding; Celgene Corporation: Research Funding; Novartis Corporation: Research Funding; Genentech: Consultancy, Research Funding. Munshi:Millennium Pharmaceuticals: Honoraria, Speakers Bureau.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2010
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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