News Article | April 18, 2017
Scientists of the Luxembourg Institute of Health (LIH) have discovered a so far unknown molecular mechanism by which the human immune system activates its immune cells: T cells, a particular type of white blood cells, effectively ward off pathogens if a gene known as Gclc is expressed within them. The Gclc gene encodes a protein instrumental for the production of a substance called glutathione - a molecule that was previously known only to eliminate harmful waste products of metabolism such as reactive oxygen species and free radicals. A team led by LIH researcher Prof Dirk Brenner, FNR ATTRACT fellow and Head of the Experimental & Molecular Immunology research group at the Department of Infection and Immunity, has discovered that glutathione also stimulates T cells' energy metabolism. This way, when in contact with pathogens, T-cells can grow, divide and fight off intruders such as viruses. Glutathione is thus an important molecular switch for the immune system. This discovery offers starting points and perspectives to develop new therapeutic strategies for targeting cancer and autoimmune diseases. The scientists publish their findings today in the world's most prestigious immunology journal, Immunity (DOI: 10.1016/j.immuni.2017.03.019.). "Our body has to keep our immune system in a carefully balanced equilibrium", says Prof Dirk Brenner. "If the body's innate defences are overactive, then they turn against the body. This is what happens in autoimmune diseases like multiple sclerosis or arthritis, for example. However if the defences are too weak, then infections cannot be handled or body cells can proliferate uncontrolled and grow to form tumours, which can become life threatening." Immune cells such as T cells therefore normally reside in a state of alert hibernation, with their energy consumption reduced to a minimum. If pathogens or parts thereof dock onto their outer envelope, then the T cells wake up and boost their metabolism. This necessarily creates greater amounts of metabolic waste products, such as reactive oxygen species (ROS) and free radicals, which can be toxic for the cells. When the concentration of these oxidants increases, the T cells have to produce more antioxidants so as not to be poisoned. No previous research group had studied the mechanism of action of antioxidants in T cells to great detail before. In exploring this phenomenon, Prof Brenner's team discovered that the antioxidant glutathione produced by T cells serves not only as a garbage collector to dispose of ROS and free radicals, it is also a key switch for energy metabolism that controls the immune response, and is thus of high relevance to various diseases. "These fascinating results form a basis for a targeted intervening in the metabolism of immune cells and for developing a new generation of immunotherapies," explains Prof Markus Ollert, Director of LIH's Department of Infection and Immunity. For their investigations, the scientists employed genetically modified mice in whose T cells the Gclc gene was removed and therefore these cells could not produce glutathione. "In these mice, we discovered that the control of viruses is impaired - mice that lack the Gclc gene have an immunodeficiency. But by the same token, this also meant the mice could not develop any autoimmune disease such as multiple sclerosis." Further tests performed by Prof. Brenner's team demonstrated the reason for this: "The mice cannot produce any glutathione in their T-cells," Prof Brenner continues, "and so a number of other signalling events that directly boost metabolism and increase energy consumption are lacking." As a result, without glutathione, T-cells do not become fully functional; they remain in their state of hibernation and no self-destructive autoimmune response occurs. Prof Karsten Hiller from the Braunschweig University of Technology who collaborated with the Luxembourgish scientists adds: "It is intriguing to see that cellular metabolism and immune activation are so tightly entangled and that a fine-grained interplay is essential to achieve a correct function." Prof Brenner sees his T cell experiments as a prelude to more in-depth investigation of the energy balance of immune cells in general. A number of different autoimmune diseases, for example, are related to malfunctions in various subgroups of T cells. "If we understand the differences in the molecular mechanisms by which they stimulate their metabolism during defensive or autoimmune responses, then we can discover clues as to possible attack points for therapeutic agents regulating the immune response." The distinguished researcher sees a similar situation in cancer: "In this context too, it is important to know why the immune cells that are actually supposed to fight cancer cells drop to a low metabolic state and in some cases even actively suppress an immune response against the tumour. Counteractive metabolism-stimulating measures could make the immune cells work more efficiently and fight off cancer more effectively." In follow-up projects, the researchers are planning to gain new indications for potential sites of therapeutic interventions. The groups from Luxembourg and Braunschweig are currently applying for new research funding for a joint project supported by the German Research Foundation (DFG) and the Luxembourg National Research Fund (FNR). Prof Dirk Brenner is the Deputy Head of Research & Strategy at LIH's Department of Infection and Immunity. He received a prestigious ATTRACT Consolidator grant from the Luxembourg National Research Fund (FNR), in 2015 to set up the Experimental & Molecular Immunology research group. The FNR-ATTRACT programme supports the national research institutions by expanding their competences in strategic research areas - by attracting outstanding young researchers with high potential to Luxembourg. The present study was performed in close collaboration with the former FNR ATTRACT fellow Prof Karsten Hiller from the Metabolomics Group at the Luxembourg Centre for Systems Biomedicine of the University of Luxembourg (now full Professor at the Integrated Centre of Systems Biology (BRICS) of the Braunschweig University of Technology, Germany) and with Prof Tak W. Mak the Director of the Campbell Family Institute for Breast Cancer Research at the University of Toronto, Canada. The Luxembourg Institute of Health is a public research organisation at the forefront of biomedical sciences. With its strong expertise in population health, oncology, infection and immunity as well as storage and handling of biological samples, its research activities are dedicated to people's health. At the Luxembourg Institute of Health, more than 300 individuals are working together, aiming at investigating disease mechanisms and developing new diagnostics, innovative therapies and effective tools to implement personalised medicine. The institution is the first supplier of public health information in Luxembourg, a strong cooperation partner in local and international projects and an attractive training place for ambitious early-stage researchers. LIH's Department of Infection and Immunity is a basic clinical-translational research entity aiming at understanding the complex mecha¬nisms of infectious and inflammatory disease processes to enable new ways to diagnose, prevent and cure human diseases. Building on a highly interdisciplinary research environment, the research strategy of the Department of Infection and Immunity focuses on experimental discovery and validation, bridging to clinical application and technology development to address major unsolved medical needs in the areas of immune-mediated inflammation (such as in allergy, asthma, autoimmunity), cancer and infectious diseases (AIDS, measles and rubella virus infection, amongst others). Prof Dirk Brenner Head of Experimental & Molecular Immunology research group Department of infection and Immunity Luxembourg Institute of Health E-mail: firstname.lastname@example.org Availability for interviews: upon request to the Communication Unit
Plate A.,Helios Klinik Bad Gandersheim |
Bitzer M.,University of Tübingen |
Foller M.,Campbell Family Institute for Breast Cancer Research
Cellular Physiology and Biochemistry | Year: 2012
Background: Sorafenib (Nexavar®), a polytyrosine kinase inhibitor, stimulates apoptosis and is thus widely used for chemotherapy in hepatocellular carcinoma (HCC). Hematological side effects of Nexavar ® chemotherapy include anemia. Erythrocytes may undergo apoptosis-like suicidal death or eryptosis, which is characterized by cell shrinkage and phosphatidylserineexposure at the cell surface. Signaling leading to eryptosis include increase in cytosolic Ca2+-activity ([Ca 2+]i), formation of ceramide, ATP-depletion and oxidative stress. The present study explored, whether sorafenib triggers eryptosis in vitro and in vivo. Methods: [Ca2+]i was estimated from Fluo3-fluorescence, cell volume from forward scatter, phosphatidylserineexposure from annexin-V-binding, hemolysis from hemoglobin release, ceramide with antibody binding-dependent fluorescence, cytosolic ATP with a luciferin-luciferase-based assay, and oxidative stress from 2',7' dichlorodihydrofluorescein diacetate (DCFDA) fluorescence. Results: A 48 h exposure of erythrocytes to sorafenib (=0.5μM) significantly increased Fluo 3. fluorescence, decreased forward scatter, increased annexin-V-binding and triggered slight hemolysis (=5μM), but did not significantly modify ceramide abundance and cytosolic ATP. Sorafenib treatment significantly enhanced DCFDA-fluorescence and the reducing agents N-acetyl-L-cysteine and tiron significantly blunted sorafenib-induced phosphatidylserine exposure. Nexavar® chemotherapy in HCC patients significantly enhanced the number of phosphatidylserine-exposing erythrocytes. Conclusions:: The present observations disclose novel effects of sorafenib, i.e. stimulation of suicidal erythrocyte death or eryptosis, which may contribute to the pathogenesis of anemia in Nexavar®-based chemotherapy. Copyright © 2012 S. Karger AG, Basel.
Al-Hussaini H.,Princess Margaret Hospital |
Subramanyam D.,University of California at San Francisco |
Reedijk M.,Princess Margaret Hospital |
Reedijk M.,Campbell Family Institute for Breast Cancer Research |
And 2 more authors.
Molecular Cancer Therapeutics | Year: 2011
The highly conserved Notch signaling pathway is involved in regulating a number of key cellular processes. This pathway has been implicated in both the development and progression of breast cancer and has emerged as a possible therapeutic target. Several clinical trials are currently underway to determine if targeting the Notch pathway with drugs such as the g-secretase inhibitors may be an effective therapeutic strategy that improves outcomes in this disease. ©2010 AACR.
Fortin J.,McGill University |
Fortin J.,Campbell Family Institute for Breast Cancer Research |
Boehm U.,Saarland University |
Deng C.-X.,U.S. National Institute of Diabetes and Digestive and Kidney Diseases |
And 2 more authors.
FASEB Journal | Year: 2014
Follicle-stimulating hormone (FSH) is an essential regulator of gonadal function and fertility. Loss-of-function mutations in the FSHB/Fshb gene cause hypogonadotropic hypogonadism in humans and mice. Both gonadotropin-releasing hormone (GnRH) and activins, members of the transforming growth factor β (TGFβ) superfamily, stimulate FSH synthesis; yet, their relative roles and mechanisms of action in vivo are unknown. Here, using conditional gene-targeting, we show that the canonical mediator of TGFβ superfamily signaling, SMAD4, is absolutely required for normal FSH synthesis in both male and female mice. Moreover, when the Smad4 gene is ablated in combination with its DNA binding cofactor Foxl2 in gonadotrope cells, mice make essentially no FSH and females are sterile. Indeed, the phenotype of these animals is remarkably similar to that of Fshb-knockout mice. Not only do these results establish SMAD4 and FOXL2 as essential master regulators of Fshb transcription in vivo, they also suggest that activins, or related ligands, could play more important roles in FSH synthesis than GnRH. © FASEB.
Robert-Tissot C.,Campbell Family Institute for Breast Cancer Research |
Speiser D.E.,Campbell Family Institute for Breast Cancer Research |
Speiser D.E.,University of Lausanne
Cancer Discovery | Year: 2016
Cross-presentation of tumor antigens represents a key pathway in antitumor immune responses that can be exploited to synergize not only with the already prominent “checkpoint blockade,” but also with newer attempts to use T-cell stimulatory monoclonal antibodies in immunotherapy. © 2016 American Association for Cancer Research.
Freedman O.,University of Toronto |
Amir E.,University of Toronto |
Zimmermann C.,Ontario Cancer Institute |
Clemons M.,University of Toronto |
Clemons M.,Campbell Family Institute for Breast Cancer Research
Supportive Care in Cancer | Year: 2011
Background: Supportive care interventions can have a substantial impact on side effects of chemotherapy. Consequently, accurate reporting of such interventions is essential when interpreting clinical trial results. This study determined the prevalence and quality of reporting of supportive care treatment for common chemotherapy-induced toxicities in phase III, breast cancer chemotherapy trials. Methods: A systematic review of phase III trials of breast cancer trials incorporating chemotherapy published in the last 5 years was undertaken. Trials were identified through MEDLINE, EMBASE, BIOSIS, and the Cochrane Library. Supportive treatments evaluated were use of antiemetics, colony-stimulating growth factors, and antibiotics. Reporting quality was rated as "good", "fair", "poor", or "absent" using predetermined criteria. Results: Sixty-two trials met inclusion criteria. In 41 studies (66%), details regarding prophylactic antiemetic treatment were not provided. Growth factor use was not reported in 20 trials (32%). Instructions for the use of prophylactic antibiotics were absent in 45 trials (72%). Conclusion: There are significant deficiencies in reporting of use of prophylactic supportive care agents in breast cancer trials. Omission of supportive care instructions may impact substantially on patient management and health care system expenditure. Recommendations for the type, dose, and frequency of supportive care drugs should be provided and reported on in trials. © 2011 Springer-Verlag.
Lind E.F.,Campbell Family Institute for Breast Cancer Research |
Lind E.F.,University of Toronto |
Ohashi P.S.,Campbell Family Institute for Breast Cancer Research |
Ohashi P.S.,University of Toronto
European Journal of Immunology | Year: 2014
The activation of T cells is a tightly regulated process that has evolved to maximize protective immune responses to pathogens while minimizing damage to self-tissues. A delicate balance of cell-intrinsic, costimulatory, and transcriptional pathways as well as micro-environmental cues such as local cytokines controls the magnitude and nature of T-cell responses in vivo. The discovery of functional small noncoding RNAs called micro-RNAs (miRNAs) has introduced new mechanisms that contribute to the regulation of protein translation and cellular responses to stimuli. miRNAs are short (approximately 22 bp) RNA species, which bind to mRNAs and suppress translation. Due to their short length and imperfect base pairing requirements, each miRNA has the potential to regulate various pathways through the translational inhibition of multiple mRNAs. The human and mouse genomes each encode hundreds of miRNAs, and studying the function of miRNAs has led to the realization that they play important roles in diverse biological processes from development and cancer to immunity. This review focuses on the function of mir-155 in T cells and the impact of this miRNA on autoimmunity, tumor immunity, and pathogen-induced immunity. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Cescon D.W.,Campbell Family Institute for Breast Cancer Research |
Cescon D.W.,University of Toronto |
Haibe-Kains B.,University of Toronto |
Mak T.W.,Campbell Family Institute for Breast Cancer Research |
Mak T.W.,University of Toronto
Proceedings of the National Academy of Sciences of the United States of America | Year: 2015
Genomic sequencing studies of breast and other cancers have identified patterns of mutations that have been attributed to the endogenous mutator activity of APOBEC3B (A3B), a member of the AID/APOBEC family of cytidine deaminases. A3B gene expression is increased in many cancers, but its upstream drivers remain undefined. Furthermore, there exists a common germ-line deletion polymorphism (A3Bdel), which has been associated with a paradoxical increase in breast cancer risk. To examine causes and consequences of A3B expression and its constitutive absence in breast cancer, we analyzed two large clinically annotated genomic datasets [The Cancer Genome Atlas (TCGA) and the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC)]. We confirmed that A3B expression is associated with aggressive clinicopathologic characteristics and adverse outcomes and show that A3B expression is highly correlated with proliferative features (mitosis and cell cycle-related gene expression) in breast and 15 of 16 other solid tumor types. However, breast cancers arising in homozygous A3Bdel individuals with A3B absent did not differ in these features, indicating that A3B expression is a reflection rather than a direct cause of increased proliferation. Using gene set enrichment analysis (GSEA), we detected a pattern of immune activation in A3Bdel breast cancers, which seems to be related to hypermutation arising in A3Bdel carriers. Together, these results provide an explanation for A3B overexpression and its prognostic effect, giving context to additional study of this mutator as a cancer biomarker or putative drug target. In addition, although immune features of A3Bdel require additional study, these findings nominate the A3Bdel polymorphism as a potential predictor for cancer immunotherapy.
George S.H.L.,Campbell Family Institute for Breast Cancer Research |
Milea A.,Campbell Family Institute for Breast Cancer Research |
Milea A.,University of Toronto |
Shaw P.A.,Campbell Family Institute for Breast Cancer Research |
Shaw P.A.,University of Toronto
Clinical Cancer Research | Year: 2012
Purpose: Women who have inherited germline mutations of BRCA1/BRCA2 are at increased risk of developing high-grade serous carcinoma, and many of these cancers arise in the distal fimbriated end of the fallopian tube. We have previously shown that the fallopian tube epithelia of BRCA1 mutation carriers (FTE-BRCA) have altered signaling pathways compared to nonmutation carriers. In this study, we sought to determine whether these differences result in a proliferative advantage to the epithelia in this high-risk patient population and to investigate whether the postovulation environment of the FTE-BRCA compared to FTE from nonmutation carriers experiences a differential abundance of immune cells. Method: Immunohistochemistry for Ki67, CD3, CD8, CD20, and CD68 was performed on histologically normal tubal epithelium (ampulla, n = 83), fimbria (n = 18) with known ovarian cycle status and germline mutation status and for Ki67 on fimbrial epithelium from women (n = 144) with and without BRCA1 or BRCA2 mutations who underwent risk-reducing salpingo-oophorectomy (RRSO). Serous tubal intraepithelial carcinomas (STIC) with concomitant cancer (n = 15) were also analyzed for presence of immune infiltrates. All slides were digitized and analyzed using automated image analysis software. Results: There was no significant difference in the proliferative index in histologically normal FTE between BRCA1/BRCA2 and non-BRCA, in 144 fimbriae and 83 ampullae. The FTE-BRCA1 epithelia did not exhibit a differential presence of lymphocytes or macrophages, however more macrophages were present in the luteal phase compared to the follicular phase epithelia. In STICs macrophages were more abundant than lymphocytes with an incremental increase noted with disease progression. Conclusions: BRCA1/2 mutation carriers exhibited no significant increase in proliferation in the fallopian tube epithelial cells either in the ampulla or fimbriated ends of the tube. Rather, a significant proliferative increase was defined in the cases determined to be in the follicular, or proliferative, preovulatory phase of the ovarian cycle. Finally, we also show an incremental increase in leukocytes invading the STICs and HGSC, implicating a possible role of the leukocytes early in the progression or inhibition of tumor formation, which is independent of ovarian cycle status. ©2012 AACR.
Cescon D.W.,Campbell Family Institute for Breast Cancer Research |
Cescon D.W.,University of Toronto |
Haibe-Kains B.,University of Toronto |
Haibe-Kains B.,Ontario Cancer Institute
Genome Biology | Year: 2016
APOBEC cytidine deaminases have been implicated as major contributors to the mutation burden in many cancers on the basis of their mutational signature. A new experimental study sheds light on the inciting factors, linking APOBEC3B expression to oncogene- and drug-induced replication stress. © 2016 The Author(s).