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  • Medizin  (634)
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  • 1
    Online-Ressource
    Online-Ressource
    American Association for Cancer Research (AACR) ; 2015
    In:  Cancer Research Vol. 75, No. 15_Supplement ( 2015-08-01), p. 2219-2219
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 75, No. 15_Supplement ( 2015-08-01), p. 2219-2219
    Kurzfassung: In contrast to errors in DNA replication which can product heritable mutations, errors in transcription cause only transient alterations. The temporary nature of these transcription mistakes has made them difficult to detect and genetic screens to identify mutations that lower the fidelity of transcription have been problematic. We addressed this problem by developing methods to turn transient transcription errors into permanent genetic changes. The principle is based on suppression of a mutation in the active site of the cre recombinase. This assay is based on two parts: a source of Cre, which is actually the transcription misincorporation substrate, and a genetic reporter with a phenotypic change created by Cre-mediated recombination between lox sites. To develop a substrate for E. coli we chose the galactokinase gene (galK) as our reporter. From an alignment of the galK protein from E.coli, H. sapiens and L. lactis we identified sites that might be able to accept a 12aa insertion encoded by the LoxP sequence without disrupting its function. We selected four different sites that were away from the GalK active site and on the surface of the protein. We started our project using the strain MG1655, which is galK (+), able to grow in galactose as a carbon source and red on a MacConkey galactose plate (MAcGal). Using oligo recombineering, we first inserted a 7 base sequence, which caused a frame-shift mutation, the cells became galK (-) and, therefore white on MacGal. To put it back in frame, we next replaced the 7 bases with a 36 base loxP site, which, if it does not disrupt the function of galK will make the cells galK (+) again. To our surprise, the insertion of this LoxP site was completely successful, putting the gene back in frame and making the cells galK (+) and, therefore, red at each of the four sites we chose. A derivative of this reporter was made with the a portion of the galK gene inverted at one of the loxP sites. Active Cre recombinase can be detected by flipping the inversion to restore galK function. The active site mutant cre-Y324C exhibits a very low inversion rate. Mutations that reduce the accuracy of transcription, such as cells defective in greA, exhibit an elevated frequency of galK (+) inversions. This system will be used to identify additional mutations that reduce the fidelity of transcription in E. coli. Citation Format: Jorge A. Irizarry-Caro, Mary Ernst, Carolyn Court, Alison Rattray, Mikhail Bubunenko, Ding Jin, Donald Court, Jeffrey Strathern. Development of an assay to detect transcription misincorporation errors in Escherichia coli. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2219. doi:10.1158/1538-7445.AM2015-2219
    Materialart: Online-Ressource
    ISSN: 0008-5472 , 1538-7445
    RVK:
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    Sprache: Englisch
    Verlag: American Association for Cancer Research (AACR)
    Publikationsdatum: 2015
    ZDB Id: 2036785-5
    ZDB Id: 1432-1
    ZDB Id: 410466-3
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Online-Ressource
    Online-Ressource
    Wiley ; 1996
    In:  International Journal of Geriatric Psychiatry Vol. 11, No. 12 ( 1996-12), p. 1063-1069
    In: International Journal of Geriatric Psychiatry, Wiley, Vol. 11, No. 12 ( 1996-12), p. 1063-1069
    Materialart: Online-Ressource
    ISSN: 0885-6230 , 1099-1166
    URL: Issue
    RVK:
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 1996
    ZDB Id: 1500455-7
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  • 3
    In: Blood, American Society of Hematology, Vol. 128, No. 22 ( 2016-12-02), p. 4142-4142
    Kurzfassung: Introduction. HIV infected individuals have an increased risk of developing lymphoma even in the era of combined antiretroviral therapy. Galectin-1 (Gal-1) is known to promote various immunomodulatory functions, including Treg expansion (Dalotto-Moreno et al, Cancer Res 2013), promotion of tolerogenic dendritic cells (Ilarregui et al, Nat Immunol 2009) and apoptosis of fully-differentiated effector T-cells (Toscano et al, Nat Immunol 2007). In the context of cancer, Gal-1 is expressed on both tumor cells and cells in the tumor microenvironment, and is usually associated with immune privilege, tumor escape and hypoxia-driven angiogenesis (Juszczynski et al, Proc Natl Acad Sci 2007; Cedeno-Laurent et al, Blood 2012). Previously, high intratumoral Gal-1 levels have been suggested as an unfavorable outcome predictor in patients with classical Hodgkin lymphoma (cHL) (Kamper et al, Blood 2011). Furthermore, several in vitro studies revealed the benefit of Gal-1 inhibition with regards to overcoming treatment resistance e.g., after anti-VEGF and anti-CD20 therapy (Croci et al, Cell 2014; Lykken et al, Blood 2016). Thus, Gal-1 inhibition may prospectively be an important tool in lymphoma treatment. In this study, we have investigated the Gal-1 expression in pre-therapeutic tumoral tissue samples from patients with HIV-associated lymphoma and its correlation to clinicopathological features at lymphoma diagnosis. Methods. Adequate pre-treatment formalin-fixed paraffin embedded samples from 40 HIV-positive lymphoma patients were included in a tissue micro array. The study samples were immunohistochemically characterized by a panel of monoclonal antibodies including CD3, CD4, CD8, CD10, CD20, CD79a (MRQ-48), CD30 (Ber-H2) and MUM1, granzyme B, CD68 and CD163. Epstein-Barr virus (EBV) proteins were visualized by latent membrane protein 1 and Epstein-Barr nuclear protein 2. Expression of EBV-encoded smallRNAs was analyzed by in-situ hybridization. Immunohistochemical cell-of-origin (COO) evaluation was carried out according to the Hans classifier. Gal-1 expression was digitally quantified as an area fraction (AF) of the total core area. Estimates of differences between groups were evaluated using Students t test, Pearsons χ2, Fisher's exact test or Spearman correlation where appropriate. Optimal cut-off values of the AF were established by a ROC analysis and calculated using Youden's index for diffuse large B-cell lymphoma (DLBCL) (n=22). Outcome was estimated by Kaplan-Meier time-to-event analyses and compared using the log-rank test. Independent prognostic values were tested by Cox-regression analysis in a multivariate model for factors showing a crude association with p 〈 0.1and proportional hazards between groups. Results. High intratumoral Gal-1 expression in HIV-associated DLBCL tissue correlated with improved outcome (p=0.041), Figure 1. Patients with high Gal-1 expression had a higher occurrence of nodal disease and B-symptoms (p=0.006). Gal-1 expression did not vary according to tumoral EBV status, latency type, International prognostic index (IPI), clinical stage or COO signature. In multivariate analysis adjusted for rituximab treatment, both Gal-1 expression and IPI retained independent prognostic value. Furthermore, intratumoral Gal-1 expression correlated positively with a Th1-signature of the tumor microenvironment including the macrophage marker CD68 (p 〈 0.001), markers of cytotoxic T-cells such as CD8 (p=0.027) and granzyme B (p 〈 0.001), together with the activation marker CD30 (p=0.006). Markers of a Th2-associated microenvironmental signature had no correlation with Gal-1 expression, except for CD163 (p 〈 0.01) that also significantly correlated with CD68 expression (p 〈 0.01). Conclusion. In HIV-associated DLBCL, intratumoral Gal-1 expression positively correlated with a Th1-signature of the tumor microenvironment. In addition, high pre-therapeutic intratumoral Gal-1 expression was found to be an independent predictor of improved outcome in HIV-associated DLBCL. Interestingly, this is the reverse of our previous findings in non-overtly immunocompromised patients with cHL (Kamper et al, Blood 2011). Further investigations on the potential clinical application of intratumoral Gal-1 expression as a predictive marker in different lymphoma types of the immunocompromised vs immunocompetent host are warranted. Figure. Figure. Disclosures d'Amore: CTI LIfe Sciences: Honoraria, Other: Advisory Boards; Servier: Honoraria, Other: Advisory Boards.
    Materialart: Online-Ressource
    ISSN: 0006-4971 , 1528-0020
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    Sprache: Englisch
    Verlag: American Society of Hematology
    Publikationsdatum: 2016
    ZDB Id: 1468538-3
    ZDB Id: 80069-7
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  • 4
    In: Blood, American Society of Hematology, Vol. 116, No. 21 ( 2010-11-19), p. 516-516
    Kurzfassung: Abstract 516 Introduction: Several studies have demonstrated the role of leukemia stem cells (LSC) in the development and maintenance of human chronic myeloid leukemia (CML). These cells, which first develop in chronic phase CML (CP CML) with acquisition of the BCR-ABL fusion protein, are often quiescent and can be highly resistant to apoptosis induced by drugs and radiotherapy that target rapidly dividing cells. Data has also shown that CML LSC become increasingly resistant to BCR-ABL inhibition with progression to blast crisis CML (BC CML). Bcl-2 family proteins are key regulators of apoptosis and have been shown by numerous studies to regulate cancer resistance to chemotherapy. This family of proteins has also been implicated in the development of BC CML, however most studies have focused on CML cell lines and their expression of Bcl-2 family proteins in vitro. Thus, there is relatively little data on expression of Bcl-2 family proteins in primary CML LSC and on the role of these proteins in regulating chemotherapy resistance in CML LSC in vivo. As Bcl-2 family proteins are known regulators of chemotherapy resistance we hypothesized that human BC CML LSC may overexpress these proteins compared to normal hematopoietic stem cells. We analyzed Bcl-2 family mRNA and protein expression in CP CML and BC CML LSC and compared this expression to normal cord blood stem and progenitor cells. We also analyzed whether these cells were sensitive to chemotherapy treatment in vitro. Finally, we tested whether a high potency pan-Bcl-2 inhibitor, 97C1, could effectively kill CML LSC in vitro and in vivo. Methods: Bcl-2 and Mcl-1 protein expression was measured in primary CP CML, BC CML, and normal cord blood cells using intracellular FACS. We also measured Bcl-2, Mcl-1, Bcl-X, and Bfl-1 mRNA expression in FACS sorted CD34+CD38+lin− cells (LSC) from these samples. For all drug studies we used either serially transplanted CD34+ cells derived from primary BC CML patient samples or primary CD34+ normal cord blood cells. In vitro drug responses were tested by culturing CD34+ cells either alone or in co-culture with a mouse bone marrow stromal cell line (SL/M2). Effects on colony formation and replating were also tested by culturing sorted CD34+CD38+lin− cells in methylcellulose in the presence and absence of drug. For in vivo testing of 97C1 we transplanted neonatal RAG2-/-yc-/- mice with CD34+ cells from 3 different BC CML and cord blood samples. Transplanted mice were screened for peripheral blood engraftment at 6–8 weeks post-transplant and engrafted mice were then treated for 2 weeks with 97C1 by IP injection. Following the treatment period the mice were sacrificed and hemotapoietic organs were analyzed for human engraftment by FACS. Results: BC CML progenitors expressed higher levels of Bcl-2 and Mcl-1 protein compared to normal cord blood and chronic phase CML cells. mRNA expression of Mcl-1, Bcl-X, and Bfl-1 was also increased in BC CML progenitors compared to CP CML progenitors. While BC CML LSC cultured in vitro were resistant to etoposide and dasatinib-induced cell death, 97C1 treatment led to a dose-dependent increase in cell death along with a dose-dependent decrease in the frequency of CD34+CD38+lin− cells compared to vehicle treated controls. While cord blood progenitor cells were also sensitive to 97C1 treatment they had an IC50 around 10 times higher than that for the BC CML cells (100nM versus 10nM). Importantly, 97C1 treatment did not inhibit cord blood colony formation or colony replating in vitro. Mice transplanted with BC CML LSC developed CML in 6–8 weeks post-transplant with diffuse myeloid sarcomas and engraftment of human CD34+CD38+lin− cells in the peripheral blood, liver, spleen, and bone marrow. In vivo treatment with 97C1 led to a significant reduction in both total human engraftment and engraftment of CD34+CD38+lin− cells in all hematopoietic organs analyzed. Conclusion: Our results demonstrate that BC CML LSC are resistant to conventional chemotherapy but are sensitive to 97C1 in vitro and in vivo. Broad-spectrum inhibition of Bcl-2 family proteins may help to eliminate CML LSC while sparing normal hematopoietic stem and progenitor cells. Disclosures: Jamieson: CoronadoBiosciences: Research Funding; CIRM: Research Funding.
    Materialart: Online-Ressource
    ISSN: 0006-4971 , 1528-0020
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    Sprache: Englisch
    Verlag: American Society of Hematology
    Publikationsdatum: 2010
    ZDB Id: 1468538-3
    ZDB Id: 80069-7
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  • 5
    In: Blood, American Society of Hematology, Vol. 110, No. 13 ( 2007-12-15), p. 4621-4622
    Materialart: Online-Ressource
    ISSN: 0006-4971 , 1528-0020
    RVK:
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    Sprache: Englisch
    Verlag: American Society of Hematology
    Publikationsdatum: 2007
    ZDB Id: 1468538-3
    ZDB Id: 80069-7
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  • 6
    Online-Ressource
    Online-Ressource
    American Society of Hematology ; 1987
    In:  Blood Vol. 69, No. 1 ( 1987-01-01), p. 278-283
    In: Blood, American Society of Hematology, Vol. 69, No. 1 ( 1987-01-01), p. 278-283
    Kurzfassung: We quantitated the amount of platelet surface-bound IgG using an 125I monoclonal anti-IgG assay in 149 patients with thrombocytopenia and 260 normal donors. The normal subjects had 122 +/- 5 molecules of IgG/platelet (mean +/- SE). Fifty-five patients with nonimmune thrombocytopenia had 338 +/- 37 molecules of IgG/platelet, whereas 67 patients with immune thrombocytopenia studied at the time of their initial evaluation had 4,120 +/- 494 molecules of IgG/platelet. An analysis of the distribution of values in these two groups indicated that 90% of the patients with immune thrombocytopenia had greater than 800 molecules of IgG/platelet, whereas only 7% of patients with nonimmune thrombocytopenia exceeded this amount. The immune thrombocytopenia patients included 39 idiopathic, 14 secondary, and 14 drug-induced disorders, and they did not significantly differ in their distribution of values for platelet IgG. The nonimmune thrombocytopenic patients included 12 cases with a platelet destructive mechanism; their platelet-bound IgG was similar to that of the other nonimmune patients. Twenty-seven patients with treatment resistant immune thrombocytopenia were also studied they had 2,100 +/- 670 molecules of IgG/platelet. Their values were significantly greater than those of the nonimmune thrombocytopenic patients and not significantly different from those of immune thrombocytopenic group. Their distribution of values was much broader, however, with 33% of patients having less than 800 molecules of IgG/platelet, suggesting possible alternate mechanisms in their thrombocytopenia. Thus, patients with immune thrombocytopenia have a high frequency of elevated IgG on the platelet surface which reflects the pathophysiology of this disorder. Quantitation of platelet-bound IgG provides a useful laboratory tool in the differential between immune and nonimmune thrombocytopenia.
    Materialart: Online-Ressource
    ISSN: 0006-4971 , 1528-0020
    RVK:
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    Sprache: Englisch
    Verlag: American Society of Hematology
    Publikationsdatum: 1987
    ZDB Id: 1468538-3
    ZDB Id: 80069-7
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  • 7
    Online-Ressource
    Online-Ressource
    American Society of Hematology ; 2018
    In:  Blood Vol. 132, No. Supplement 1 ( 2018-11-29), p. 3698-3698
    In: Blood, American Society of Hematology, Vol. 132, No. Supplement 1 ( 2018-11-29), p. 3698-3698
    Kurzfassung: The interactions between platelets and cancer cells activate platelets and enhance tumor growth. The ability of a cancer cell line to activate platelets in vitro, tumor cell-induced platelet aggregation (TCIPA), predicts the in vivo aggressiveness of that particular cancer cell line. We have found that platelets extravasate into tumor microenvironment. We also have shown that ovarian cancer cells secret ADP that activate platelets by binding to P2Y12 (an ADP receptor on platelets). In turn, activated platelets enhance proliferation of ovarian cancer cells and tumor growth. Activated platelets release TGFβ to the tumor microenvironment (TME) that enhances cancer cell proliferation in a TGFβ dose-dependent manner. Platelet TGFβ also functions as an immune modulator by enhancing differentiation of T cells toward T-reg. Platelets not only increase cancer cell proliferation but also alter the immune response to cancer by suppressing the function of tumor-infiltrating T cells. The presence of tumor-infiltrating lymphocytes (TIL) is associated with a significant improvement in the progression-free survival (PFS) and the overall survival (OS) of patients with ovarian cancer. In the current study, we investigated the effect of platelet inhibition on promoting the immune response to tumors and the therapeutic benefit of combining anti-platelet reagents with checkpoint inhibitors (CPIs) in murine models of ovarian cancer. We have shown before, P2Y12 deficient (P2Y12-/-) and platelet specific TGFβ knockout (TGFβfl/fl;PF4-cre) mice developed smaller tumors compared to control tumor-bearing mice in a murine ovarian cancer model. To determine the effect of anti-platelet reagent in platelet extravasation into the TME, we counted the number of platelets in the TME in four groups of tumor-bearing mice: control, aspirin-treated (ASA), platelet infused (Plt) and aspirin-treated + platelet-infused (Asp Plt) mice. Platelet extravasation increased after platelet infusion and reduced after aspirin treatment. The groups with a higher number of extravasated platelets developed larger tumors compared to those with less extravasated platelets. We investigated the role of platelet in regulation of immune response to tumor using mice with platelet specific defects in murine models of ovarian cancer. We immune profiled tumors induced in mice with platelet-specific TGFβ deficiency, P2Y12 deficient mice, and aspirin or Ticagrelor-treated mice. Overall platelet functional defects was associated with an increase in the number of T cells, DC, MØ and NK and a decrease in the number of MDSCs in tumors.. We investigated the effect of immune check point inhibitors (CPI) on growth of murine ovarian cancer. We administrated 200µg of combination of CPIs (anti-CTLA4/ anti-PD-L1) into tumor-bearing mice. Combined CPI therapy had a minimal effect on the tumor burden (control=0.53± 0.082g vs. CPIs=0.33± 0.04g, p=0.15). Although CPI-treatment increased the number of CD8 cells inside tumors, it also increased the expression of VISTA (a negative) with an overall non-significant effect on the tumor growth. To investigate the effect of platelet inhibition on expression of checkpoint regulatory proteins in the TME, the expression of VISTA was examined in the tumors resected from TGFβfl/fl; PF4-cre tumor-bearing mice by quantitative RT-PCR (qRT-PCR), and was compared to that in tumors resected from WT tumor bearing mice. Tumors from TGFβfl/fl; PF4-cre mice expressed less VISTA mRNA (control= 1 vs. TGFβfl/fl; PF4-cre= 0.04 ± 0.01, p 〈 0.0001). Interestingly, P2Y12 deficiency and antiplatelet reagents (ticagrelor and aspirin) also reduced expression of VISTA in tumors. This is the first evidence for the effect of platelet inhibition on the expression of a checkpoint regulator in tumors. We hypothesize that platelet inhibition enhances anti-tumor immune response and can be used as an adjuvant to checkpoint inhibitors in immunotherapies for ovarian cancer. Disclosures No relevant conflicts of interest to declare.
    Materialart: Online-Ressource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Sprache: Englisch
    Verlag: American Society of Hematology
    Publikationsdatum: 2018
    ZDB Id: 1468538-3
    ZDB Id: 80069-7
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  • 8
    In: American Journal of Respiratory and Critical Care Medicine, American Thoracic Society, Vol. 200, No. 9 ( 2019-11-01), p. 1183-1187
    Materialart: Online-Ressource
    ISSN: 1073-449X , 1535-4970
    RVK:
    Sprache: Englisch
    Verlag: American Thoracic Society
    Publikationsdatum: 2019
    ZDB Id: 1468352-0
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  • 9
    In: Journal of Clinical Oncology, American Society of Clinical Oncology (ASCO), Vol. 34, No. 15_suppl ( 2016-05-20), p. 11050-11050
    Materialart: Online-Ressource
    ISSN: 0732-183X , 1527-7755
    RVK:
    RVK:
    Sprache: Englisch
    Verlag: American Society of Clinical Oncology (ASCO)
    Publikationsdatum: 2016
    ZDB Id: 2005181-5
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  • 10
    In: American Journal of Respiratory and Critical Care Medicine, American Thoracic Society, Vol. 162, No. 2 ( 2000-08-01), p. 571-577
    Materialart: Online-Ressource
    ISSN: 1073-449X , 1535-4970
    RVK:
    Sprache: Englisch
    Verlag: American Thoracic Society
    Publikationsdatum: 2000
    ZDB Id: 1468352-0
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