Publications by authors named "Katharina Kolbe"

Article Synopsis
  • Scientists studied tiny particles called extracellular vesicles (EVs) in the blood of glioblastoma patients to see if they could help doctors know more about the disease.
  • They found that glioblastoma patients had a lot more EVs in their blood than healthy people, and more EVs meant a shorter survival time for patients.
  • The amount of EVs changed after surgery and could even show when a patient's tumor was getting worse before doctors could see it on scans.
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Rhizochalinin (Rhiz) is a recently discovered cytotoxic sphingolipid synthesized from the marine natural compound rhizochalin. Previously, Rhiz demonstrated high in vitro and in vivo efficacy in various cancer models. Here, we report Rhiz to be highly active in human glioblastoma cell lines as well as in patient-derived glioma-stem like neurosphere models.

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The CRISPR/Cas system has a broad range of possible medical applications, but its clinical translation has been hampered, particularly by the lack of safe and efficient vector systems mediating the short-term expression of its components. Recently, different virus-like particles (VLPs) have been introduced as promising vectors for the delivery of CRISPR/Cas genome editing components. Here, we characterized and directly compared three different types of retrovirus-based (R) VLPs, two derived from the γ-retrovirus murine leukemia virus (gRVLPs and "enhanced" egRVLPs) and one from the lentivirus human immunodeficiency virus, HIV (LVLPs).

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Purpose: The prospective multicenter VARIANZ study aimed to identify resistance biomarkers for HER2-targeted treatment in advanced gastric and esophago-gastric junction cancer (GC, EGJC). HER2 test deviations were found in 90 (22.3%) of 404 cases (central versus local testing) and were associated with negative impact on survival for trastuzumab-treated patients.

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Background: Pulmonary Tuberculosis (TB) is diagnosed through sputum samples. As sputum sampling is challenging in children and cachexic patients, the development of diagnostic tests using saliva appears promising but has been discouraged due to low bacterial load and poor sensitivity. Here, we present a novel and rapid method to enrich Mycobacterium tuberculosis (Mtb) from saliva, which may serve as a basis for a diagnostic saliva test.

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Background: Extracellular vesicles (EVs) play an important role in cell-cell communication, and tumor-derived EVs circulating in patient blood can serve as biomarkers. Here, we investigated the potential role of plasma EVs in meningioma patients for tumor detection and determined whether EVs secreted by meningioma cells reflect epigenetic, genomic, and proteomic alterations of original tumors.

Methods: EV concentrations were quantified in patient plasma (n = 46).

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Background: γδ T cells are unconventional T cells that have been demonstrated to be crucial for the pathogenesis and potentially for the cure of HIV-1 infection. The ectonucleotidase CD39 is part of the purinergic pathway that regulates immune responses by degradation of pro-inflammatory ATP in concert with CD73. Few studies on the expression of the ectoenzymes CD73 and CD39 on human γδ T cells in HIV have been performed to date.

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Purpose: Trastuzumab is the only approved targeted drug for first-line treatment of human epidermal growth factor receptor 2-positive (HER2+) metastatic gastric cancer (mGC). However, not all patients respond and most eventually progress. The multicenter VARIANZ study aimed to investigate the background of response and resistance to trastuzumab in mGC.

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resides in the lungs in various lesion types with unique microenvironmental conditions. This diversity is in line with heterogeneous disease progression and divergent drug efficiency. Fluorescent reporter strains can be used to decipher the micromilieu and to guide future treatment regimens.

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Immunotherapeutic strategies are increasingly important in neuro-oncology, and the elucidation of escape mechanisms that lead to treatment resistance is crucial. We investigated the impact of immune pressure on the clonal dynamics and immune escape signature by comparing glioma growth in immunocompetent versus immunodeficient mice. Glioma-bearing WT and Pd-1-/- mice survived significantly longer than immunodeficient Pfp-/- Rag2-/- mice.

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Extracellular vesicles (EVs) are known for their important role in cancer progression and hold considerable potential as a source for tumor biomarkers. However, purification of tumor-specific EVs from patient plasma is still an urgent unmet need due to contamination by normal host cell-derived EVs, that results in compromised analytical sensitivity. Here we identified fatty acid synthase (FASN), a key lipogenic enzyme which is highly expressed in malignant glioma cells, to be elevated in CD63- and CD81-positive EVs in glioma patient plasma samples, opening vital opportunities to sort brain tumor-specific EVs.

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Article Synopsis
  • - Cells release extracellular vesicles (EVs) like exosomes and microvesicles, which play critical roles in physiology and diseases, especially cancer, and can serve as potential biomarkers.
  • - Traditional bulk analysis methods for EVs have limitations, but imaging flow cytometry (IFCM) allows for detailed examination of individual EVs and the identification of specific subpopulations based on surface markers.
  • - The study illustrates that EVs have unique profiles and that specific subpopulations, particularly those with CD63/CD81 markers, are particularly present in cancer samples, suggesting that IFCM could enhance disease modeling and future research applications.
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The importance of bacterial lectins for adhesion, pathogenicity, and biofilm formation is well established for many Gram-positive and Gram-negative bacteria. However, there is very little information available about lectins of the tuberculosis-causing bacterium, (). In this paper we review previous studies on the carbohydrate-binding characteristics of mycobacteria and related proteins, discussing their potential relevance to infection and pathogenesis.

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Hard-to-heal wounds are associated with high treatment costs and, in Germany, are mostly treated in the outpatient care sector. Wound dressings are the main cost-drivers in venous leg ulcer (VLU) care which prescription is budget-restricted. To determine to what extent the choice of antimicrobial dressing affects the spending in outpatient care by investigating the budget impact of the bioburden-reducing dressing Cutimed Sorbact.

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BRI family proteins are ubiquitous type II transmembrane proteins but BRI2 is highly expressed in some neuronal tissues. Possible BRI2 functions include neuronal maturation and differentiation. Protein complexes appear to be important in mediating its functions.

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The use of chemical techniques to study biological systems (often referred to currently as chemical biology) has become a powerful tool for both drug discovery and the development of novel diagnostic strategies. In tuberculosis, such tools have been applied to identifying drug targets from hit compounds, matching high-throughput screening hits against large numbers of isolated protein targets and identifying classes of enzymes with important functions. Metabolites unique to mycobacteria have provided important starting points for the development of innovative tools.

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A series of precision glycomacromolecules is prepared following previously established solid phase synthesis allowing for controlled variations of interligand spacing and the overall number of carbohydrate ligands. In addition, now also different linkers are installed between the carbohydrate ligand and the macromolecular scaffold. The lectin binding behavior of these glycomacromolecules is then evaluated in isothermal titration calorimetry (ITC) and kinITC experiments using the lectin Concanavalin A (Con A) in its dimeric and tetrameric form.

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Pathogenic mycobacteria of the Mycobacterium tuberculosis complex (MTBC) have co-evolved with their individual hosts and are able to transform the hostile environment of the macrophage into a permissive cellular habitat. The impact of MTBC genetic variability has long been considered largely unimportant in TB pathogenesis. Members of the MTBC can now be distinguished into three major phylogenetic groups consisting of 7 phylogenetic lineages and more than 30 so called sub-lineages/subgroups.

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Alzheimer's disease (AD) is the most common neurodegenerative disease with tens of millions of people affected worldwide. The pathogenesis is still poorly understood and various therapeutical approaches targeting the amyloid β (Aβ) peptide, a product of the amyloidogenic cleavage of the amyloid precursor protein (APP), failed. Moreover, a couple of studies critically questioned the relevance of Aβ in the pathogenesis of AD.

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Background: Human hippocampal area Cornu Ammonis (CA) 1 is one of the first fields in the human telencephalon showing Alzheimer disease (AD)-specific neuropathological changes. In contrast, CA2 and CA3 are far later affected pointing to functional differences, which may be accompanied by differences in proteome endowment and changes.

Methods: Human pyramidal cell layers of hippocampal areas CA1, CA2, and CA3 from neurologically unaffected individuals were excised using laser microdissection.

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Mycobacterium tuberculosis (Mtb), the main causative agent of tuberculosis (Tb), has a complex cell envelope which forms an efficient barrier to antibiotics, thus contributing to the challenges of anti-tuberculosis therapy. However, the unique Mtb cell wall can be considered an advantage and be utilized to selectively label Mtb bacteria. Here we introduce three azido pentoses as new compounds for metabolic labeling of Mtb: 3-azido arabinose (3AraAz), 3-azido ribose (3RiboAz), and 5-azido arabinofuranose (5AraAz).

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Nuclear spheres are protein aggregates consisting of FE65, TIP60, BLM, and other yet unknown proteins. Generation of these structures in the cellular nucleus is putatively modulated by the amyloid precursor protein (APP), either by its cleavage or its phosphorylation. Nuclear spheres were preferentially studied in cell culture models and their existence in the human brain had not been known.

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A central molecular hallmark of Alzheimer's disease (AD) is the β- and γ-secretase-mediated cleavage of the amyloid precursor protein (APP), which causes the generation of different c-terminal fragments like C99, AICD57, or AICD50 that fully or in part contain the APP transmembrane domain. In this study, we demonstrate that membrane-tethered C99 is phosphorylated by JNK3A at residue T668 (APP695 numbering) to a higher extent than AICD57, whereas AICD50 is not capable of being phosphorylated. The modification decreases the turnover of APP, while the blockade of APP cleavage increases APP phosphorylation.

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The effect of galectin-mediated microdomain formation on the spatiotemporal dynamics of glycosylated membrane proteins in human microvascular endothelial cells (HMEC-1) was studied qualitatively and quantitatively by high-resolution fluorescence microscopy and artificially mimicked by metabolic glycoprotein engineering. Two types of membrane proteins, sialic acid-bearing proteins (SABPs) and mucin-type proteins (MTPs), were investigated. For visualization they were metabolically labeled with azido sugars and then coupled to a cyclooctyne-conjugated fluorescent dye by click chemistry.

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Background: The treatment efficacy of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors like erlotinib has not met expectations for glioblastoma therapy, even for EGFR-overexpressing tumors. We determined possible mechanisms of therapy resistance using the unique BS153 glioblastoma cell line, which has retained amplification of the egfr gene and expression of EGFR variant (v)III.

Methods: Functional effects of erlotinib, gefitinib, and cetuximab on BS153 proliferation, migration, and EGFR-dependent signal transduction were systematically compared in vitro.

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