Tumor cell integrin β4 and tumor stroma E-/P-selectin cooperatively regulate tumor growth in vivo

Background: The immunological composition of the tumor microenvironment has a decisive influence on the biological course of cancer and is therefore of profound clinical relevance. In this study, we analyzed the cooperative effects of integrin β4 (ITGB4) on tumor cells and E-/P-selectin on endothelial cells within the tumor stroma for regulating tumor growth by shaping the local and systemic immune environment. Methods: We used several preclinical mouse models for different solid human cancer types (xenograft and syngeneic) to explore the role of ITGB4 (shRNA-mediated knockdown in tumor cells) and E-/P-selectins (knockout in mice) for tumor growth; effects on apoptosis, proliferation and intratumoral signaling pathways were determined by histological and biochemical methods and 3D in vitro experiments; changes in the intratumoral and systemic immune cell composition were determined by flow cytometry and immunohistochemistry; chemokine levels and their attracting potential were measured by ELISA and 3D invasion assays. Results: We observed a very robust synergism between ITGB4 and E-/P-selectin for the regulation of tumor growth, accompanied by an increased recruitment of CD11b + Gr-1 Hi cells with low granularity (i.e., myeloid-derived suppressor cells, MDSCs) specifically into ITGB4-depleted tumors. ITGB4-depleted tumors undergo apoptosis and actively attract MDSCs, well-known to promote tumor growth in several cancers, via increased secretion of different chemokines. MDSC trafficking into tumors crucially depends on E-/P-selectin expression. Analyses of clinical samples confirmed an inverse relationship between ITGB4 expression in tumors and number of tumor-infiltrating leukocytes. Conclusions: These findings suggest a distinct vulnerability of ITGB4 Lo tumors for MDSC-directed immunotherapies. Graphical Abstrac

Cleavage site-directed antibodies reveal the prion protein in humans is shed by ADAM10 at Y226 and associates with misfolded protein deposits in neurodegenerative diseases

Proteolytic cell surface release (‘shedding’) of the prion protein (PrP), a broadly expressed GPI-anchored glycoprotein, by the metalloprotease ADAM10 impacts on neurodegenerative and other diseases in animal and in vitro models. Recent studies employing the latter also suggest shed PrP (sPrP) to be a ligand in intercellular communication and critically involved in PrP-associated physiological tasks. Although expectedly an evolutionary conserved event, and while soluble forms of PrP are present in human tissues and body fluids, for the human body neither proteolytic PrP shedding and its cleavage site nor involvement of ADAM10 or the biological relevance of this process have been demonstrated thus far. In this study, cleavage site prediction and generation (plus detailed characterization) of sPrP-specific antibodies enabled us to identify PrP cleaved at tyrosin 226 as the physiological and apparently strictly ADAM10-dependent shed form in humans. Using cell lines, neural stem cells and brain organoids, we show that shedding of human PrP can be stimulated by PrP-binding ligands without targeting the protease, which may open novel therapeutic perspectives. Site-specific antibodies directed against human sPrP also detect the shed form in brains of cattle, sheep and deer, hence in all most relevant species naturally affected by fatal and transmissible prion diseases. In human and animal prion diseases, but also in patients with Alzheimer`s disease, sPrP relocalizes from a physiological diffuse tissue pattern to intimately associate with extracellular aggregated deposits of misfolded proteins characteristic for the respective pathological condition. Findings and research tools presented here will accelerate novel insight into the roles of PrP shedding (as a process) and sPrP (as a released factor) in neurodegeneration and beyond

Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches

Extracellular vesicles (EVs), through their complex cargo, can reflect the state of their cell of origin and change the functions and phenotypes of other cells. These features indicate strong biomarker and therapeutic potential and have generated broad interest, as evidenced by the steady year-on-year increase in the numbers of scientific publications about EVs. Important advances have been made in EV metrology and in understanding and applying EV biology. However, hurdles remain to realising the potential of EVs in domains ranging from basic biology to clinical applications due to challenges in EV nomenclature, separation from non-vesicular extracellular particles, characterisation and functional studies. To address the challenges and opportunities in this rapidly evolving field, the International Society for Extracellular Vesicles (ISEV) updates its 'Minimal Information for Studies of Extracellular Vesicles', which was first published in 2014 and then in 2018 as MISEV2014 and MISEV2018, respectively. The goal of the current document, MISEV2023, is to provide researchers with an updated snapshot of available approaches and their advantages and limitations for production, separation and characterisation of EVs from multiple sources, including cell culture, body fluids and solid tissues. In addition to presenting the latest state of the art in basic principles of EV research, this document also covers advanced techniques and approaches that are currently expanding the boundaries of the field. MISEV2023 also includes new sections on EV release and uptake and a brief discussion of in vivo approaches to study EVs. Compiling feedback from ISEV expert task forces and more than 1000 researchers, this document conveys the current state of EV research to facilitate robust scientific discoveries and move the field forward even more rapidly

FASN Is a Biomarker Enriched in Malignant Glioma-Derived Extracellular Vesicles

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

Tumor cell communication through EVs: new challenges and opportunities

Extracellular vesicles (EVs) are small, heterogeneous, lipid-bilayer particles that are potent vehicles of intercellular communication, contributing to the interaction of tumor cells with the microenvironment and promoting tumor growth. Furthermore, EVs have gained substantial interest due to their potential utility for liquid biopsy approaches in cancer.</jats:p

Characterization of Disease Patterns in Children with Intracranial Abscesses for Enhanced Clinical Decision-Making

Background: Intracranial suppurative infections in pediatric patients, while rare, pose a significant risk to patient mortality. Early recognition and fast initiation of diagnosis and treatment are crucial to prevent fatal outcomes. Between December 2022 and May 2023, a significant cluster of nine cases emerged, each necessitating neurosurgical intervention. This series highlights an important trend in clinical outcomes and raises questions about underlying factors contributing to this pattern. The need for surgical procedures in all instances suggests a commonality in severity, warranting further investigation into potential causes and preventative measures. This retrospective monocentric study aims to explore the clinical features associated with these cases to identify specific disease patterns that can expedite management in clinical practice. Methods: Cramer’s V effect size was employed to evaluate combinations of clinical features, followed by Fisher’s exact test applied to a constructed contingency table. A p-value was assessed for significance analysis, with combinations achieving a Cramer’s V value of 0.7 or higher being classified as exhibiting very strong correlations. Results: The analysis revealed distinct patterns of clinical features among children diagnosed with intracranial abscesses. Significant associations were identified, including correlations between sinusitis and Streptococcus pyogenes, and fever accompanied by affected temporal, frontal, and frontobasal lobe regions. Conclusions: Despite the generally limited statistical analysis of pediatric intracranial abscesses in the existing literature, this study provides meaningful significant associations between clinical features, delineating specific disease patterns for children with intracranial abscesses. By addressing this gap, the findings contribute valuable insights and offer a framework that could enhance clinical decision-making and support timely disease management in pediatric cases

Immune Escape Mediated by Exosomal PD‐L1 in Cancer

Extracellular vesicles (EVs) are now well established as important mediators of intercellular communication. EVs constitute a diverse group of secreted vesicles which function by the delivery of protein and nucleic acid cargoes from donor to recipient cells. In cancer, tumor cell-derived EVs are shown to promote disease progression by facilitating local reprogramming of the tumor microenvironment. EVs also have more distant systemic effects via transport in biofluids, and therefore have great potential as biomarkers for disease detection and monitoring. Recently, the discovery that EVs derived from glioblastoma cells can mediate immunosuppression by activation of immune checkpoint signaling and T cell dysfunction was reported. Mechanistically we showed that this occurs via direct binding of PD-L1 secreted in EVs, to its receptor PD1 expressed on the surface of activated T cells. This previously unidentified mechanism of tumor immunosuppression has been confirmed in subsequent independent studies, which have demonstrated the biologic importance of this mechanism across multiple tumor types. These studies have established a new and significant paradigm in which PD-L1 containing tumor cell-derived EVs cause immune suppression by the direct engagement of PD1 on T cells, decreasing their activation and providing a further barrier to protect tumors from T cell killing

Features of tumor texture influence surgery and outcome in intracranial meningioma

Abstract Background Texture-related factors such as consistency, vascularity, and adherence vary considerably in meningioma and are thought to be linked with surgical resectability and morbidity. However, data analyzing the true impact of meningioma texture on the surgical management is sparse. Methods Patients with intracranial meningioma treated between 08/2014 and 04/2018 at our institution were prospectively collected for demographics, clinical presentation, histology, and surgical treatment with related morbidity and extend of resection. Tumor characteristics were reported by the surgeon using a standardized questionnaire including items such as tumor consistency, homogeneity, vascularization, and adherence to surrounding neurovascular structure and analyzed for their impact surgical outcome parameters using univariate and logistic regression analyses. Results Tumor texture-related parameters of 300 patients (72.3% female) with meningioma were analyzed. Meningioma localizations were grouped into 3 different cohorts namely convexity, skull base, and posterior. Postoperative occurrence of a neurological deficit (transient 23.0%; permanent 6.1%) was associated with the duration of surgery (P = .001), size of tumor (P = .046), tumor vascularization (P = .015), and adherence to neurovascular structures (P = .002). Coherently, the duration of surgery (mean 230.99 ± 101.33 min) was associated with size of tumor (P &amp;lt; .0001), vascularization (P &amp;lt; .0001), and adherence (P &amp;lt; .0001). Similar associations were recapitulated in subgroup analyses of different tumor localizations. Noteworthy, tumor rigidity had no significant impact on time of surgery and neurological outcome. Conclusions Our analysis demonstrates that tumor texture has an impact on the surgical management of meningioma and provides data that tumor vascularization and adherence are significant factors influencing surgical outcome whereas the influence of tumor consistency has less impact than previously thought. </jats:sec