Chemisch induzierte Resistenz im Pathosystem Weizen - Echter Weizenmehltau : Cytologische und molekulare Funktionsanalyse eines Benzothiadiazols

Durch synthetische Resistenzinduktoren wie BTH (Benzo[1,2,3]thiadiazol-7-carbothionsäure-S- methylester) und anderen Funktionsanaloga der Salizylsäure ist man heute in der Lage, das Phänomen der systemisch Induzierten Resistenz (SIR) in Pflanzen zu kopieren und ihnen so einen lang anhaltenden Schutz gegenüber einem breiten Spektrum an Pathogenen zu verleihen. Die Mechanismen, welche der chemisch Induzierten Resistenz (CIR) in Getreide zugrunde liegen, sind bis heute weitgehend ungeklärt und wurden in der vorliegenden Arbeit anhand des Pathosystems Weizen- Echter Weizenmehltau cytologisch, biochemisch und molekular-biologisch analysiert. Dazu wurden zunächst die cytologischen Abwehrmechanismen, welche der CIR zugrunde liegen, aufgeklärt. Es zeigte sich, daß die CIR mit einer Steigerung der basalen Resistenz der Pflanzen durch Bildung effektiver Penetrationsbarrieren (Papillen) und hypersensitiven Zelltod (HR) nach einer Pathogenattacke einhergeht. Die Behandlung von Weizen mit BTH führt zur Expression verschiedener Gene mit teilweise unbekannter Funktion. Einige von ihnen sind spezifisch in der CIR exprimiert und werden deshalb als Markergene angesehen. Die zeitlichen und räumlichen Expressionsmuster von vier Genen konnten in Northern Analysen und in situ Hybridisierungen aufgeklärt werden. Durch den Vergleich verschiedener Applikationsmethoden von BTH in Kombination mit Infektion durch Bgt konnten Hinweise auf die Bedeutung dieser Gene für die CIR gewonnen werden. Für WCI-3 und PR-1 konnte aufgrund der Expressionsprofile und ihrer Ähnlichkeiten zu anderen bekannten Genen gezeigt werden, daß sie wahrscheinlich eine Aufgabe bei der unmittelbaren Pathogenabwehr haben. In Western Analysen konnte für PR-1 ein priming-Effekt nachgewiesen werden. Das bedeutet, daß der Weizen nach einer Behandlung mit BTH, früher und stärker PR-1 akkumuliert und so effektiver auf den Pathogenbefall reagieren kann. WCI-1 und LOX sind Gene, welche wahrscheinlich eine Rolle bei der Signaltransduktion spielen. Eine Funktion von WCI-1 in der Signaltransduktionskette nach BTH-Applikation liegt nahe, da WCI-1 früh und in räumlicher Assoziation zum Applikationsort des Induktors exprimiert wurde. Für die LOX konnte gezeigt werden, daß sie ein Schlüsselelement der CIR sein kann, da sie unabhängig von der Applikationsart des Induktors zelltypspezifisch in Leitbündelscheidezellen und direkt angrenzenden Mesophyllzellen exprimiert wurde.The natural phenomenon of systemic induced resistance (SIR) is mimicked by application of the chemical BTH (benzo[1,2,3]thiadiazole-7-carbothioic acid S-methyl ester, acibenzolar-S-methyl) or other functional analogues of salicylic acid. Chemically Induced Resistance (CIR) in plants leads to a long lasting protection against a broad range of phytopathogens. How chemically induced plants respond to pathogens is not well understood. Here, defence mechanisms were analysed on the cytological, biochemical and molecular level in the pathosystem wheat - wheat powdery mildew fungus. As a result of CIR the basal resistance is increased. Wheat plants treated with BTH showed a more frequent formation of effective penetration barriers (papillae) and a hypersensitive reaction upon pathogen attack. BTH treatment leads to expression of a set of genes partly with unknown function. Some of these genes are used as marker genes for CIR, since they are expressed specifically after application of chemical resistance inductors. Temporal and spatial expression patterns of four chemically induced genes were studied. Comparing different types of chemical application in combination with inoculation of Bgt, conclusions regarding the importance of these genes in defence or signal transduction could be drawn. WCI-3 and PR1 appeared to be involved directly in pathogen defence because they show similarities to antifungal proteins and are expressed in cells at the frontline between plant and fungus. In western analyses, a priming effect for PR1 was demonstrated. This implies, that PR1 was expressed in chemically induced plants that were challenged by Bgt-inoculation stronger and earlier than in control plants which may contribute to effectiveness of defence. WCI-1 and LOX are genes that might be involved in signal transduction after BTH application. This is likely for WCI-1, because it was expressed rapidly and directly at the site of inductor application. Interestingly, LOX was expressed independent of the type of application, in cells of the vascular bundle sheath and the adjacent mesophyll. Therefore, the lipoxygenase might be a key enzyme engaged in local or systemic signal processing

A randomized phase II study of radiation induced immune boost in operable non-small cell lung cancer (RadImmune trial)

Background: Lung cancer is the leading cause of cancer deaths worldwide. Surgery, radiotherapy at conventional and high dose and chemotherapy are the mainstay for lung cancer treatment. Insufficient migration and activation of tumour specific effector T cells seem to be important reasons for inadequate host anti-tumour immune response. Ionizing radiation can induce a variety of immune responses. The goal of this randomized trial is to assess if a preoperative single fraction low dose radiation is able to improve anti-tumour immune response in operable early stage lung cancer. Methods/Design: This trial has been designed as an investigator-initiated, prospective, randomized, 2-armed phase II trial. Patients who are candidates for elective resection of early stage non-small cell lung cancer will be randomized into 2 arms. A total of 36 patients will be enrolled. The patients receive either 2 Gy or no radiation prescribed to their primary tumour. Radiation will be delivered by external beam radiotherapy using 3D radiotherapy or intensity-modulated radiation technique (IMRT) 7 days prior to surgical resection. The primary objective is to compare CD8+ T cell counts detected by immunohistochemistry in resected tumours following preoperative radiotherapy versus no radiotherapy. Secondary objectives include the association between CD8+ T cell counts and progression free survival, the correlation of CD8+ T cell counts quantified by immunohistochemistry and flow cytometry, local tumour control and recurrence patterns, survival, radiogenic treatment toxicity and postoperative morbidity and mortality. Further, frequencies of tumour reactive T cells in blood and bone marrow as well as whole blood cell transcriptomics and plasma-proteomics will be correlated with clinical outcome. Discussion: This unique intervention combining preoperative low dose radiation and surgical removal of early stage non-small cell lung cancer is designed to address the problem of inadequate host anti-tumour immune response. If successful, this study may affect the role of radiotherapy in lung cancer treatment. Trial registration: NCT02319408; Registration: December 29, 2014

Rapid disease progression on immune checkpoint inhibitors in young patients with stage IV melanoma

BackgroundImmune checkpoint inhibitors (ICIs) are the standard of care for metastatic cutaneous melanoma (mCM) patients, but their efficacy in young adults aged less than 40 years remains unclear.Materials and methodsWe retrospectively analyzed 303 stage IV melanoma patients of different ages treated with nivolumab, pembrolizumab, or ipilimumab plus nivolumab combination therapy. Clinical data and blood values such as LDH, CRP, and absolute immune cell counts were retrieved from the medical records. Pre-treatment serum concentrations of soluble immune checkpoint proteins were measured using ELISA. In addition, information on frequencies of various T cell subsets in the peripheral blood was collected from a previously reported study (ELEKTRA). Patient characteristics and clinical information was correlated with PFS and OS using univariate and multivariate cox regression analysis.ResultsOf 303 patients, 33 (11%) were ≤ 40 years old. The older patients had a median age of 64 (95% CI: 61–66). Concerning prognostic parameters, there was no difference between the age groups, e.g., in gender, LDH, or the existence of brain or liver metastases. Patients aged ≤ 40 years [p = 0.014; HR: 1.6 (95% CI: 1.1–2.4)], presence of liver metastases [p = 0.016; HR: 1.4 (95% CI: 1.0–1.9)], line of ICI treatment [p = 0.009; HR: 1.4 (1.0–1.9)], elevated LDH [p = 0.076; HR: 1.3 (95% CI: 0.97–1.8)], and brain metastasis [p = 0.080; HR: 1.3 (95% CI: 0.97–1.7)], were associated with shorter PFS in univariate analysis. Multivariate analysis revealed that the patient’s age (≤ 40 years) remains a high-risk factor upon adjusting for all potential confounders [p = 0.067; HR: 1.5 (95% CI: 0.97–2.3)]. Blood parameters revealed that patients ≤ 40 years have relatively higher frequencies of activated CD4 T cells (CD4 + Ki67 + CD4 + ICOS +) in the blood, and significantly lower number of basophils and CD45RA- memory T cells, compared to patients above 40 years (p < 0.05). In addition, patients ≤ 40 years experiencing disease progression within 6 months of ICI treatment had increased concentrations of sPDL1 (p = 0.05) and sTIM3 (p = 0.054) at baseline.ConclusionYoung patients with stage IV melanoma may experience shorter progression-free survival upon ICI treatment compared to patients above 40 years and are characterized by fewer basophils and memory T cells in the blood

Low-density lipoprotein balances T cell metabolism and enhances response to anti-PD-1 blockade in a HCT116 spheroid model

IntroductionThe discovery of immune checkpoints and the development of their specific inhibitors was acclaimed as a major breakthrough in cancer therapy. However, only a limited patient cohort shows sufficient response to therapy. Hence, there is a need for identifying new checkpoints and predictive biomarkers with the objective of overcoming immune escape and resistance to treatment. Having been associated with both, treatment response and failure, LDL seems to be a double-edged sword in anti-PD1 immunotherapy. Being embedded into complex metabolic conditions, the impact of LDL on distinct immune cells has not been sufficiently addressed. Revealing the effects of LDL on T cell performance in tumor immunity may enable individual treatment adjustments in order to enhance the response to routinely administered immunotherapies in different patient populations. The object of this work was to investigate the effect of LDL on T cell activation and tumor immunity in-vitro. MethodsExperiments were performed with different LDL dosages (LDLlow = 50 μg/ml and LDLhigh = 200 μg/ml) referring to medium control. T cell phenotype, cytokines and metabolism were analyzed. The functional relevance of our findings was studied in a HCT116 spheroid model in the context of anti-PD-1 blockade.ResultsThe key points of our findings showed that LDLhigh skewed the CD4+ T cell subset into a central memory-like phenotype, enhanced the expression of the co-stimulatory marker CD154 (CD40L) and significantly reduced secretion of IL-10. The exhaustion markers PD-1 and LAG-3 were downregulated on both T cell subsets and phenotypical changes were associated with a balanced T cell metabolism, in particular with a significant decrease of reactive oxygen species (ROS). T cell transfer into a HCT116 spheroid model resulted in a significant reduction of the spheroid viability in presence of an anti-PD-1 antibody combined with LDLhigh.DiscussionFurther research needs to be conducted to fully understand the impact of LDL on T cells in tumor immunity and moreover, to also unravel LDL effects on other lymphocytes and myeloid cells for improving anti-PD-1 immunotherapy. The reason for improved response might be a resilient, less exhausted phenotype with balanced ROS levels

A randomized controlled trial to investigate the influence of low dose radiotherapy on immune stimulatory effects in liver metastases of colorectal cancer

<p>Abstract</p> <p>Background</p> <p>Insufficient migration and activation of tumor specific effector T cells in the tumor is one of the main reasons for inadequate host anti-tumor immune response. External radiation seems to induce inflammation and activate the immune response. This phase I/II clinical trial aims to evaluate whether low dose single fraction radiotherapy can improve T cell associated antitumor immune response in patients with colorectal liver metastases.</p> <p>Methods/Design</p> <p>This is an investigator-initiated, prospective randomised, 4-armed, controlled Phase I/II trial. Patients undergoing elective hepatic resection due to colorectal cancer liver metastasis will be enrolled in the study. Patients will receive 0 Gy, 0.5 Gy, 2 Gy or 5 Gy radiation targeted to their liver metastasis. Radiation will be applied by external beam radiotherapy using a 6 MV linear accelerator (Linac) with intensity modulated radiotherapy (IMRT) technique two days prior to surgical resection. All patients admitted to the Department of General-, Visceral-, and Transplantion Surgery, University of Heidelberg for elective hepatic resection are consecutively screened for eligibility into this trial, and written informed consent is obtained before inclusion. The primary objective is to assess the effect of active local external beam radiation dose on, tumor infiltrating T cells as a surrogate parameter for antitumor activity. Secondary objectives include radiogenic treatment toxicity, postoperative morbidity and mortality, local tumor control and recurrence patterns, survival and quality of life. Furthermore, frequencies of systemic tumor reactive T cells in blood and bone marrow will be correlated with clinical outcome.</p> <p>Discussion</p> <p>This is a randomized controlled patient blinded trial to assess the safety and efficiency of low dose radiotherapy on metastasis infiltrating T cells and thus potentially enhance the antitumor immune response.</p> <p>Trial registration</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT01191632">NCT01191632</a></p

Double-blind, placebo-controlled first in human study to investigate an oral vaccine aimed to elicit an immune reaction against the VEGF-Receptor 2 in patients with stage IV and locally advanced pancreatic cancer

BACKGROUND: The investigational oral DNA vaccine VXM01 targets the vascular endothelial growth factor receptor 2 (VEGFR-2) and uses Salmonella typhi Ty21a as a vector. The immune reaction elicited by VXM01 is expected to disrupt the tumor neovasculature and, consequently, inhibit tumor growth. VXM01 potentially combines the advantages of anti-angiogenic therapy and active immunotherapy. METHODS/DESIGN: This phase I trial examines the safety, tolerability, and immunological and clinical responses to VXM01. The randomized, placebo-controlled, double blind dose-escalation study includes up to 45 patients with locally advanced and stage IV pancreatic cancer. The patients will receive four doses of VXM01 or placebo in addition to gemcitabine as standard of care. Doses from 10(6) cfu up to 10(10) cfu of VXM01 will be evaluated in the study. An independent data safety monitoring board (DSMB) will be involved in the dose-escalation decisions. In addition to safety as primary endpoint, the VXM01-specific immune reaction, as well as clinical response parameters will be evaluated. DISCUSSION: The results of this study shall provide the first data regarding the safety and immunogenicity of the oral anti-VEGFR-2 vaccine VXM01 in cancer patients. They will also define the recommended dose for phase II and provide the basis for further clinical evaluation, which may also include additional cancer indications. TRIAL REGISTRATION: EudraCT No.: 2011-000222-29, NCT01486329, ISRCTN6880927

Cellular Immune Responses and Immune Escape Mechanisms in Breast Cancer: Determinants of Immunotherapy

More recently, immunotherapy has emerged as a novel potentially effective therapeutic option also for solid malignancies such as breast cancer (BC). Relevant approaches, however, are determined by the 2 main elements of cancer immunoediting - the elimination of nascent transformed cells by immunosurveillance on the one hand and tumor immune escape on the other hand. Correspondingly, we here review the role of the various cellular immune players within the host-protective system and dissect the mechanisms of immune evasion leading to tumor progression. If the immune balance of disseminated BC cell dormancy (equilibrium phase) is lost, distant metastatic relapse may occur. The relevant cellular antitumor responses and translational immunotherapeutic options will also be discussed in terms of clinical benefit and future directions in BC management

Exploiting the glioblastoma peptidome to discover novel tumour-associated antigens for immunotherapy

Peptides presented at the cell surface reflect the protein content of the cell; those on HLA class I molecules comprise the critical peptidome elements interacting with CD8 T lymphocytes. We hypothesize that peptidomes from ex vivo tumour samples encompass immunogenic tumour antigens. Here, we uncover >6000 HLA-bound peptides from HLA-A*02+ glioblastoma, of which over 3000 were restricted by HLA-A*02. We prioritized in-depth investigation of 10 glioblastoma-associated antigens based on high expression in tumours, very low or absent expression in healthy tissues, implication in gliomagenesis and immunogenicity. Patients with glioblastoma showed no T cell tolerance to these peptides. Moreover, we demonstrated specific lysis of tumour cells by patients' CD8+ T cells in vitro. In vivo, glioblastoma-specific CD8+ T cells were present at the tumour site. Overall, our data show the physiological relevance of the peptidome approach and provide a critical advance for designing a rational glioblastoma immunotherapy. The peptides identified in our study are currently being tested as a multipeptide vaccine (IMA950) in patients with glioblastom

Randomized controlled phase I/II study to investigate immune stimulatory effects by low dose radiotherapy in primarily operable pancreatic cancer

<p>Abstract</p> <p>Background</p> <p>The efficiencies of T cell based immunotherapies are affected by insufficient migration and activation of tumor specific effector T cells in the tumor. Accumulating evidence exists on the ability of ionizing radiation to modify the tumor microenvironment and generate inflammation. The aim of this phase I/II clinical trial is to evaluate whether low dose single fraction radiotherapy can improve T cell associated antitumor immune response in patients with pancreatic cancer.</p> <p>Methods/Design</p> <p>This trial has been designed as an investigator initiated; prospective randomised, 4-armed, controlled Phase I/II trial. Patients who are candidates for resection of pancreatic cancer will be randomized into 4 arms. A total of 40 patients will be enrolled. The patients receive 0 Gy, 0.5 Gy, 2 Gy or 5 Gy radiation precisely targeted to their pancreatic carcinoma. Radiation will be delivered by external beam radiotherapy using a 6 MV Linac with IMRT technique 48 h prior to the surgical resection. The primary objective is the determination of an active local external beam radiation dose, leading to tumor infiltrating T cells as a surrogate parameter for antitumor activity. Secondary objectives include local tumor control and recurrence patterns, survival, radiogenic treatment toxicity and postoperative morbidity and mortality, as well as quality of life. Further, frequencies of tumor reactive T cells in blood and bone marrow as well as whole blood cell transcriptomics and plasma-proteomics will be correlated with clinical outcome. An interim analysis will be performed after the enrolment of 20 patients for safety reasons. The evaluation of the primary endpoint will start four weeks after the last patient's enrolment.</p> <p>Discussion</p> <p>This trial will answer the question whether a low dose radiotherapy localized to the pancreatic tumor only can increase the number of tumor infiltrating T cells and thus potentially enhance the antitumor immune response. The study will also investigate the prognostic and predictive value of radiation-induced T cell activity along with transcriptomic and proteomic data with respect to clinical outcome.</p> <p>Trial registration</p> <p>ClinicalTrials.gov - <a href="http://www.clinicaltrials.gov/ct2/show/NCT01027221">NCT01027221</a></p