Immune evasion mediated by PD-L1 on glioblastoma-derived extracellular vesicles

Mechanism of LINC01018/miR-182-5p/Rab27B in the immune escape through PD-L1-mediated CD8+ T cell suppression in glioma

BACKGROUND

Glioma is a malignant tumor associated with poorer prognosis. This study aims to elucidate the mechanism of LINC01018/miR-182-5p/Rab27B axis in PD-L1-mediated CD8+ T cell suppression in the progression of gliomas.

METHODS

LINC01018, miR-182-5p, and Rab27B expression levels in glioblastoma tissues were measured. The proportion of infiltrating macrophages and monocytes and CD8+ T cell function were assessed. The relationship between miR-182-5p and Rab27B was analyzed. Glioma cell activity, invasion, and migration were measured. The expression of E-cadherin, N-cadherin, Vimentin, PD-L1, iNOS, and CD206 was determined. Glioma cell-derived EVs were isolated, and the co-localization of Rab27B and PD-L1 and the binding of Rab27B to PD-L1 were analyzed. The endocytosis of EVs by microglia was assayed. The impact of LINC01018/miR-182-5p/Rab27B on glioma growth was observed. The function of macrophages and CD8+ T cells in tumors was analyzed.

RESULTS

Rab27B was downregulated, and infiltrating macrophages and monocytes were increased in glioblastoma. miR-182-5p inhibited Rab27B expression. Rab27B knockdown reverses the inhibitory effect of LINC01018 overexpression on glioma cell growth. Glioma cells-derived EVs with low Rab27B expression carried more PD-L1 to increase PD-L1 expression and M2 polarization in microglia. LINC01018 overexpression reduced macrophages in orthotopic tumors. CD8+ T cell numbers showed no significant difference, but TIM-3 increased and IFN-γ decreased. miR-182-5p inhibition enhanced the therapeutic effect of anti-PD-L1, which was reversed after glioma cell-derived EVs.

CONCLUSION

LINC01018 promotes PD-L1-mediated CD8+ T cell suppression via the miR-182-5p/Rab27B axis in glioma cell-derived EVs, thereby contributing to immune escape in gliomas.

Ruxolitinib suppresses tumor growth in PTEN-deficient glioblastoma by inhibiting the STAT3-PDL1 axis-mediated the M2 polarization of macrophages

BACKGROUND

Glioblastoma (GBM) is the most malignant form of brain tumor, and GBM patients with poorer prognosis and highly immunosuppressive tumor microenvironment (TME) often exhibit PTEN deficiency in their tumor tissues. Therefore, new therapeutic strategies targeting immunosuppressive TME maybe useful in PTEN-deficient GBM.

METHODS

Bioinformatics was used to assess gene expression, survival time and immunoinfiltration in PTEN-deficient GBM. CRISPR-Cas9 was used to construct gene knockout cell lines. C57BL/6 mouse orthotopic GBM models were used to conduct survival analysis and evaluate treatment effect of Ruxolitinib. Flow cytometry, immunohistochemistry, immunofluorescence and quantitative real-time PCR (qRT-PCR) to detect the polarization of macrophages. Immunoblotting, immunohistochemistry, qRT-PCR, enzyme linked immunosorbent assay, and dual-luciferase reporter assay were used to conduct mechanism research.

RESULTS

We identified that the elevated levels of phosphorylated STAT3 (p-STAT3) in PTEN-deficient GBM facilitate PDL1 transcription, which subsequently drives M2 polarization of macrophages. Furthermore, PTEN deficiency, along with high expression levels of STAT3 and PDL1, are associated with a shorter survival time in GBM patients. Notably, in orthotopic mouse models of GBM with PTEN deficiency, Ruxolitinib therapy reduces the levels of p-STAT3 and PDL1, inhibits the infiltration of M2 macrophages, and suppresses tumor growth.

CONCLUSIONS

The STAT3-PDL1 axis plays a crucial role in the M2 polarization of macrophages in PTEN-deficient GBM. The blockade of the STAT3-PDL1 axis by Ruxolitinib regulates the anti-tumor immune response and curtails tumor progression in PTEN-deficient GBM, highlighting its significant clinical implications.

The potential of plasma-derived medium-sized extracellular vesicles as a biopsy alternative for active surveillance decisions in prostate Cancer

Diagnosing prostate cancer (PCa) and risk-stratifying patients remains challenging, as PSA-based methods lack precision for active surveillance (AS) decision-making. Extracellular vesicles (EVs) are membranous nano-sized vesicles released by all types of cells and may contain potentially interesting material for diagnostic procedures for PCa. This study analyzed surface markers and miRNA profiles of medium-sized plasma EVs (mEVs) from 24 PCa patients using nanoflow cytometry and miRNA profiling. The ratio of PSMA+ EVs to PSMA+CD9+ EVs differed significantly between AS and non-AS patients. Additionally, miR-99a-5p, miR-125b-5p, miR-145-5p, and miR-365a-3p levels were higher in non-AS patients. These findings suggest that plasma-derived PSMA+ mEVs originate from the prostate and may serve as biomarkers for PCa progression. Nanoflow cytometry-based analysis of EV surface markers combined with miRNA profiling provides a novel, non-invasive alternative to PSA measurements. This approach could improve risk stratification and decision-making for AS patients, potentially leading to better outcomes.

Tumor-derived extracellular vesicles: Hijacking T cell function through exhaustion

Extracellular vesicles (EVs) play a vital role in intercellular communication within the tumor microenvironment (TME). These vesicles, secreted by tumor cells, contain proteins, lipids, and nucleic acids that significantly influence immune responses, particularly impacting T-cell function. In cancer, T cell dysfunction and exhaustion-marked by reduced proliferation, diminished cytokine production, and impaired cytotoxic activity-are key barriers to effective immune responses. Tumor-derived extracellular vesicles (TEVs) contribute to this dysfunction by carrying immunosuppressive molecules, such as transforming growth factor-beta (TGF-β) and various microRNAs (miRNAs). These TEV-mediated mechanisms promote T cell exhaustion and foster a broader immunosuppressive environment, enabling tumor progression and immune evasion. Furthermore, TEVs have been implicated in resistance to cancer immunotherapies, including immune checkpoint inhibitors and T cell therapies. Understanding the molecular pathways and cargoes within TEVs that drive T cell dysfunction is crucial for developing novel therapeutic strategies aimed at reinvigorating exhausted T cells, enhancing anti-tumor immunity, and improving cancer treatment outcomes.

Extracellular vesicles as cancer biomarkers and drug delivery strategies in clinical settings: Advances, perspectives, and challenges

Cancer is a leading cause of death worldwide, and despite the introduction of new therapeutic approaches for advanced cases aimed at improving patient survival, only a subset of patients benefits from a complete response. In this context, there is a growing need for new cancer biomarkers and therapeutic strategies, and the use of Extracellular Vesicles (EVs) has been widely explored in various approaches. As circulating lipid-bilayer particles carrying a variety of biological information from tumor cells, EVs can be employed as good biomarkers of diagnosis, prognosis, therapy evaluation, and as adjuvants in cancer treatment. In this review, we provide a brief overview of the different types of EVs and their biogenesis and discuss how tumor-derived EV cargo can serve as a potential biomarker in clinical settings through liquid biopsy. We also highlight recent advances in EV nanoengineering and their potential as adjuvants in cancer treatment. Finally, we discuss the key unknowns, gaps, and bottlenecks that must be addressed to fully integrate EVs into precision oncology.

Advances in liquid biopsy and virtual biopsy for care of patients with glioma: a narrative review

INTRODUCTION

The World Health Organization's 2021 classification of central nervous system neoplasms incorporated molecular and genetic features for classifying gliomas. Classification of gliomas located in deep-seated structures became a clinical conundrum given the absence of crucial pathological and molecular data. Advances in noninvasive imaging modalities offered virtual biopsy as a novel solution to this problem by identifying surrogate radiomic signatures. Liquid biopsies of blood or cerebrospinal fluid provided another enormous opportunity for identifying genomic, metabolomic and proteomic signatures.

AREAS COVERED

We summarize and appraise the current state of evidence with regards to virtual biopsy and liquid biopsy in the care of patients with gliomas. PubMed, Embase and Google Scholar were searched on 7/30/2024 for relevant articles published after the year 2013 in the English language.

EXPERT OPINION

A large body of preclinical and preliminary clinical evidence suggests that virtual biopsy is possible with the combined use of multiple novel imaging modalities in conjunction with machine learning and radiomics. Likewise, liquid biopsy in conjunction with focused ultrasound may be a valuable tool to obtain proteomic and genomic data regarding glioma in a minimally invasive manner. These modalities will likely become an integral part of care for patients with glioma in the future.

Extracellular membrane particles en route to the nucleus - exploring the VOR complex

Intercellular communication is an essential hallmark of multicellular organisms for their development and adult tissue homeostasis. Over the past two decades, attention has been focused on communication mechanisms based on various membrane structures, as illustrated by the burst of scientific literature in the field of extracellular vesicles (EVs). These lipid bilayer-bound nano- or microparticles, as vehicle-like devices, act as regulators in various biological and physiological processes. When EVs are internalized by recipient cells, their membrane and cytoplasmic cargoes can interfere with cellular activities, affecting pathways that regulate cell proliferation, differentiation, and migration. In cancer, EVs can transfer oncogenic factors, stimulate neo-angiogenesis and immunosuppression, reprogram stromal cells, and confer drug resistance traits, thereby remodeling the surrounding microenvironment. Although the mechanisms underlying EV biogenesis and uptake are now better understood, little is known about the spatiotemporal mechanism(s) of their actions after internalization. In this respect, we have shown that a fraction of endocytosed EVs reaches the nuclear compartment via the VOR (VAP-A-ORP3-Rab7) complex-mediated docking of late endosomes to the outer nuclear membrane in the nucleoplasmic reticulum, positioning and facilitating the transfer of EV cargoes into the nucleoplasm via nuclear pores. Here, we highlight the EV heterogeneity, the cellular pathways governing EV release and uptake by donor and recipient cells, respectively, and focus on a novel intracellular pathway leading to the nuclear transfer of EV cargoes. We will discuss how to intercept it, which could open up new avenues for clinical applications in which EVs and other small extracellular particles (e.g., retroviruses) are implicated.

Exosome-based immunotherapy in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a significant global health concern and ranks as the third leading cause of cancer-associated mortality. Systemic therapy faces the emergence of resistance, which hinders the clinical benefits. Recent evidence suggests that exosomes, measuring between 30 and 150 nm in size, which impact the antitumor immune responses, making them a promising candidate for cancer immunotherapy. Owing to their unique physical and chemical characteristics, exosomes can be tailored and engineered for a range of therapeutic objectives. In the present review, we outline the immunomodulatory functions of exosomes in the tumor microenvironment (TME) of HCC, aiming to decipher the underlying mechanisms of exosomes in remodeling suppressive TME. Moreover, we provide detailed and intuitive resource for leveraging the potential of exosomes in immunotherapy, presenting valuable strategies to improve and optimize HCC treatment. Despite the huge therapeutic potential of exosomes, significant challenges persist, including the need for standardization in exosome production, optimization of cargo loading techniques, and the assurance of safety and effectiveness in clinical applications. Addressing these challenges may pave the way for exosome-based immunotherapy for HCC patients.

Regulatory T Cell Mimicry by a Subset of Mesenchymal GBM Stem Cells Suppresses CD4 and CD8 Cells

Attempts to activate an anti-tumor immune response in glioblastoma (GBM) have been met with many challenges due to its inherently immunosuppressive tumor microenvironment. The degree and mechanisms by which molecularly and phenotypically diverse tumor-propagating glioma stem cells (GSCs) contribute to this state are poorly defined. In this study, our multifaceted approach combining bioinformatics analyses of clinical and experimental datasets, single-cell sequencing, and the molecular and pharmacologic manipulation of patient-derived cells identified GSCs expressing immunosuppressive effectors mimicking regulatory T cells (Tregs). We showed that this immunosuppressive Treg-like (ITL) GSC state is specific to the mesenchymal GSC subset and is associated with and driven specifically by TGFβ type II receptor (TGFBR2) in contrast to TGFBR1. Transgenic TGFBR2 expression in patient-derived GBM neurospheres promoted a mesenchymal transition and induced a six-gene ITL signature consisting of CD274 (PD-L1), NT5E (CD73), ENTPD1 (CD39), LGALS1 (galectin-1), PDCD1LG2 (PD-L2), and TGFB1. This TGFBR2-driven ITL signature was identified in clinical GBM specimens, patient-derived GSCs, and systemic mesenchymal malignancies. TGFBR2high GSCs inhibited CD4+ and CD8+ T cell viability and their capacity to kill GBM cells, effects reversed by pharmacologic and shRNA-based TGFBR2 inhibition. Collectively, our data identify an immunosuppressive GSC state that is TGFBR2-dependent and susceptible to TGFBR2-targeted therapeutics.

Extracellular vesicles as the common denominator among the 7 Rs of radiobiology: From the cellular level to clinical practice

Extracellular vesicles (EVs) are lipid-bound particles released by tumor cells and widely explored in cancer development, progression, and treatment response, being considered as valuable components to be explored as biomarkers or cellular targets to modulate the effect of therapies. The mechanisms underlying the production and profile of EVs during radiotherapy (RT) require addressing radiobiological aspects to determine cellular responses to specific radiation doses and fractionation. In this review, we explore the role of EVs in the 7 Rs of radiobiology, known as the molecular basis of a biological tissue response to radiation, supporting EVs as a shared player in all the seven processes. We also highlight the relevance of EVs in the context of liquid biopsy and resistance to immunotherapy, aiming to establish the connection and utility of EVs as tools in contemporary and precision radiotherapy.

Cancer Cell Line Classification Using Raman Spectroscopy of Cancer-Derived Exosomes and Machine Learning

Liquid biopsies are an emerging, noninvasive tool for cancer diagnostics, utilizing biological fluids for molecular profiling. Nevertheless, the current methods often lack the sensitivity and specificity necessary for early detection and real-time monitoring. This work explores an advanced approach to improving liquid biopsy techniques through machine learning analysis of the Raman spectra measured to classify distinct exosome solutions by their cancer origin. This was accomplished by conducting principal component analysis (PCA) of the Raman spectra of exosomes from three cancer cell lines (COLO205, A375, and LNCaP) to extract chemically significant features. This reduced set of features was then utilized to train a linear discriminant analysis (LDA) classifier to predict the source of the exosomes. Furthermore, we investigated differences in the lipid composition in these exosomes by their spectra. This spectral similarity analysis revealed differences in lipid profiles between the different cancer cell lines as well as identified the predominant lipids across all exosomes. Our PCA-LDA framework achieved 93.3% overall accuracy and F1 scores of 98.2%, 91.1%, and 91.0% for COLO205, A375, and LNCaP, respectively. Our results from spectral similarity analysis were also shown to support previous findings of lipid dynamics due to cancer pathology and pertaining to exosome function and structure. These findings underscore the benefits of enhancing Raman spectroscopy analysis with machine learning, laying the groundwork for the development of early noninvasive cancer diagnostics and personalized treatment strategies. This work potentially establishes the foundation for refining the classification model and optimizing exosome extraction and detection from clinical samples for clinical translation.

Exosomal PD-L1 in non-small cell lung Cancer: Implications for immune evasion and resistance to immunotherapy

Exosomes, characterized by their bilayer lipid structure, are crucial in mediating intercellular signaling and contributing to various physiological processes. Tumor cells produce distinct exosomes facilitating cancer progression, angiogenesis, and metastasis by conveying signaling molecules. A notable feature of these tumor-derived exosomes is the presence of programmed death-ligand 1 (PD-L1) on their surface. The PD-L1/programmed cell death receptor-1 (PD-1) signaling axis serves as a critical immune checkpoint, enabling tumors to evade immune detection and antitumor activity. The advancement of immunotherapy targeting the PD-1/PD-L1 pathway has significantly impacted the treatment landscape for non-small cell lung cancer (NSCLC). Despite its promise, evidence indicates that many patients experience limited responses or develop resistance to PD-1/PD-L1 inhibitors. Recent studies suggest that exosomal PD-L1 contributes to this resistance by modulating immune responses and tumor adaptability. This study reviews the PD-1/PD-L1 pathway's characteristics, current clinical findings on PD-L1 inhibitors in NSCLC, and exosome-specific attributes, with a particular focus on exosomal PD-L1. Furthermore, it examines the growing body of research investigating the role of exosomal PD-L1 in cancer progression and response to immunotherapy, underscoring its potential as a target for overcoming resistance in NSCLC treatment.

High-throughput capture and in situ protein analysis of extracellular vesicles by chemical probe-based array

Extracellular vesicles (EVs) are small particles with phospholipid bilayers that carry a diverse range of cargoes including nucleic acids, proteins and metabolites. EVs have important roles in various cellular processes and are increasingly recognized for their ubiquitous role in cell-cell communications and potential applications in therapeutics and diagnostics. Although many methods have been developed for the characterization and measurement of EVs, analyzing them from biofluids remains a challenge with regard to throughput and sensitivity. Recently, we introduced an approach to facilitate high-throughput analysis of EVs from trace amounts of sample. In this method, an amphiphile-dendrimer supramolecular probe (ADSP) is coated onto a nitrocellulose membrane for array-based capture and to enable an in situ immunoblotting assay. Here, we describe the protocol for our array-based method of EV profiling. We describe an enhanced version of the method that incorporates an automated printing workstation, ensuring high throughput and reproducibility. We further demonstrate the use of our array to profile specific glycosylations on the EV surface using click chemistry of an azide group introduced by metabolic labeling. In this protocol, the synthesis of ADSP and the fabrication of ADSP nitrocellulose membrane array can be completed on the same day. EVs are efficiently captured from biological or clinical samples through a 30-min incubation, followed by an immunoblotting assay within a 3-h window, thus providing a high-throughput platform for EV isolation and in situ targeted analysis of EV proteins and their modifications.

Unlocking the therapeutic potential of tumor-derived EVs in ischemia-reperfusion: a breakthrough perspective from glioma and stroke

Clinical studies have revealed a bidirectional relationship between glioma and ischemic stroke, with evidence of spatial overlap between the two conditions. This connection arises from significant similarities in their pathological processes, including the regulation of cellular metabolism, inflammation, coagulation, hypoxia, angiogenesis, and neural repair, all of which involve common biological factors. A significant shared feature of both diseases is the crucial role of extracellular vesicles (EVs) in mediating intercellular communication. Extracellular vesicles, with their characteristic bilayer structure, encapsulate proteins, lipids, and nucleic acids, shielding them from enzymatic degradation by ribonucleases, deoxyribonucleases, and proteases. This structural protection facilitates long-distance intercellular communication in multicellular organisms. In gliomas, EVs are pivotal in intracranial signaling and shaping the tumor microenvironment. Importantly, the cargos carried by glioma-derived EVs closely align with the biological factors involved in ischemic stroke, underscoring the substantial impact of glioma on stroke pathology, particularly through the crucial roles of EVs as key mediators in this interaction. This review explores the pathological interplay between glioma and ischemic stroke, addressing clinical manifestations and pathophysiological processes across the stages of hypoxia, stroke onset, progression, and recovery, with a particular focus on the crucial role of EVs and their cargos in these interactions.

Self-Localized Plasmonic Nanocavity Strategy for the Glycosylation Detection of Glioblastoma Extracellular Vesicles

The protein glycosylation of extracellular vesicles (EVs) is involved in cellular recognition and emerges as a promising biomarker for cancer diagnosis. However, the lack of efficient labeling and high-resolution detection strategies limits their clinical application. Herein, we developed a self-localized plasmonic nanocavity strategy to analyze the glycosylation characteristics of glioblastoma EVs. First, an engineered phospholipid bilayer structure with a Au nanoring array was designed to capture EVs and induce membrane fusion. Relying on the multifunctional proximity labeling process, a peroxidase-induced proximity labeling was designed to label sialic acid on programmed cell death ligand 1 (PD-L1) of EVs. Based on the identification and labeling process of EVs, the plasmonic nanocavity was self-localized with Au nanocubes and achieved the spontaneous location of MoSe2 QDs. The uniformly enhanced electromagnetic field in the nanocavity resulted in the polarized luminescence signal of MoSe2 QDs for improving the detection sensitivity and resolution. This system demonstrated the precise distinction and sensitive quantification of EV glycosylation in cerebrospinal fluid to distinguish glioblastoma. This research provided a novel strategy for the glycosylation detection of EVs and promoted the clinical application of EVs in glioblastoma diagnosis.

Tumor-derived extracellular vesicle PD-1 promotes tumor immune evasion via disruption of peripheral T cell homeostasis

The programmed cell death 1 (PD-1)/PD-1 ligand 1 (PD-L1) axis mediates immune evasion of tumor, and targeting this axis has achieved some clinical benefits. The regulation of PD-1 expression in immune cells has been well studied. However, whether any other potential source of immune cell-expressed PD-1 exists remains unknown. Here, we report that tumor cells express PD-1 and release PD-1 in the form of extracellular vesicles, which enters T cells and suppresses T cell function via PD-L1 in vitro. In vivo, tumor cell-derived extracellular vesicle PD-1 promotes tumor growth via disrupting peripheral T cell homeostasis, showing by decreased number of T cells and impaired function of CD8+ T cells in spleens, draining lymph nodes and tumor infiltrating lymphocytes, which is restored by PD-1-targeted antibodies. Our study provides a unique and novel perspective for immune evasion of tumor, and expands a source of PD-1 in immune cells.

Extracellular Vesicle-Based Strategies for Tumor Immunotherapy

Immunotherapy is one of the most promising approaches for cancer management, as it utilizes the intrinsic immune response to target cancer cells. Normally, the human body uses its immune system as a defense mechanism to detect and eliminate foreign objects, including cancer cells. However, cancers develop a 'switch off' mechanism, known as immune checkpoint proteins, to evade immune surveillance and suppress immune activation. Therefore, significant efforts have been made to develop the strategies for stimulating immune responses against cancers. Among these, the use of extracellular vesicles (EVs) to enhance the anti-tumor immune response has emerged as a particularly promising approach in cancer management. EVs possess several unique properties that elevate the potency in modulating immune responses. This review article provides a comprehensive overview of recent advances in this field, focusing on the strategic usage of EVs to overcome tumor-induced immune tolerance. We discuss the biogenesis and characteristics of EVs, as well as their potential applications in medical contexts. The immune mechanisms within the tumor microenvironment and the strategies employed by cancers to evade immune detection are explored. The roles of EVs in regulating the tumor microenvironment and enhancing immune responses for immunotherapy are also highlighted. Additionally, this article addresses the challenges and future directions for the development of EV-based nanomedicine approaches, aiming to improve cancer immunotherapy outcomes with greater precision and efficacy while minimizing off-target effects.

Engineered Immunomodulatory Extracellular Vesicles from Epithelial Cells with the Capacity for Stimulation of Innate and Adaptive Immunity in Cancer and Autoimmunity

Extracellular vesicles (EVs) are generated in all cells. Systemic administration of allogenic EVs derived from epithelial and mesenchymal cells has been shown to be safe, despite carrying an array of functional molecules, including thousands of proteins. To address whether epithelial cell-derived EVs can be modified to acquire the capacity to induce an immune response, we engineered 293T EVs to harbor the immunomodulatory molecules CD80, OX40L, and PD-L1. We demonstrated abundant levels of these proteins in the engineered cells and EVs. Functionally, the engineered EVs efficiently elicited positive and negative costimulation of human and murine T cells. In the setting of cancer and autoimmune hepatitis, the engineered EVs modulated T cell functions and altered disease progression. OX40L EVs also provided enhanced antitumor activity in combination with anti-CTLA-4 in melanoma-bearing mice. In addition, we added multiple immunomodulatory proteins in EVs (EVmIM), attempting to elicit an immune response in both lymphoid and myeloid compartments. The EVmIM containing CD80, 4-1BBL, CD40L, CD2, and CD32 engaged both T cells and antigen presenting cells (APCs) in melanoma tumors, demonstrating the capacity for EVmIM to elicit antitumor activity. Our work provides evidence that EVs can be engineered to induce specific immune responses with translational potential to modulate immune cell functions in pathological settings.

PTEN loss in glioma cell lines leads to increased extracellular vesicle biogenesis and PD-L1 cargo in a PI3K-dependent manner

Phosphatase and Tensin Homolog (PTEN) is one of the most frequently lost tumor suppressors in cancer and the predominant negative regulator of the PI3K-AKT signaling axis. A growing body of evidence has highlighted the loss of PTEN with immuno-modulatory functions including the upregulation of the programmed death ligand-1 (PD-L1), an altered tumor-derived secretome that drives an immunosuppressive tumor immune microenvironment and resistance to certain immunotherapies. Given their roles in immunosuppression and tumor growth, we examined whether the loss of PTEN would impact the biogenesis, cargo, and function of extracellular vesicles (EVs) in the context of the anti-tumor associated cytokine interferon-γ. Through genetic and pharmacological approaches, we show that total cellular expression of PD-L1 is regulated by JAK/STAT signaling, not PI3K signaling. Instead, we observe that PTEN loss specifically upregulates cell surface levels of PD-L1 and enhances the biogenesis of EVs enriched with PD-L1 in a PI3K-dependent manner. We demonstrate that because of these changes, EVs derived from glioma cells lacking PTEN have a greater ability to suppress T cell receptor signaling. Taken together, these findings provide important new insights into how the loss of PTEN can contribute to an immunosuppressive tumor immune microenvironment, facilitate immune evasion, and highlight a novel role for PI3K signaling in the regulation of EV biogenesis and the cargo they contain.

Exosomes as carriers to stimulate an anti-cancer immune response in immunotherapy and as predictive markers

During this era of rapid advancements in cancer immunotherapy, the application of cell-released small vesicles that activate the immune system is of considerable interest. Exosomes are cell-derived nanovesicles that show great promise for the immunological treatment of cancer because of their immunogenicity and molecular transfer capacity. Recent technological advancements have enabled the identification of functional functions that exosome cargoes perform in controlling immune responses. Exosomes are originated specifically from immune cells and tumor cells and they show unique composition patterns directly related to the immunotherapy against cancer. Exosomes can also deliver their cargo to particular cells, which can affect the phenotypic and immune-regulatory functions of those cells. Exosomes can influence the course of cancer and have therapeutic benefits by taking part in several cellular processes; as a result, they have the dual properties of activating and restraining cancer. Exosomes have tremendous potential for cancer immunotherapy; they may develop into the most powerful cancer vaccines and carriers of targeted antigens and drugs. Comprehending the potential applications of exosomes in immune therapy is significant for regulating cancer progression. This review offers an analysis of the function of exosomes in immunotherapy, specifically as carriers that function as diagnostic indicators for immunological activation and trigger an anti-cancer immune response. Moreover, it summarizes the fundamental mechanism and possible therapeutic applications of exosome-based immunotherapy for human cancer.

Esophageal squamous cell carcinoma derived sEV-PDL1 exhausts CD8+T cells to promote immunosuppression

Esophageal squamous cell carcinoma (ESCC) is a common malignancy. Programmed death ligand 1 of small extracellular vesicles (sEV-PDL1) induce immune evasion and enhance tumor progression. However, the role of ESCC derived sEV-PDL1 in modulating CD8+T cell remains unclear. sEVs were isolated through differential centrifugation. CD8+T cells were isolated, stimulated and cultured with sEVs to evaluate the proportions, phenotypes, and functions by flow cytometry. Lentivirus infection and Crisper-Cas9 were used to constructed stable transgenic cell lines: Eca109-PDL1kd and mEC25-PDL1ko. The proportions of CD8+T cells in ESCC patients was lower than healthy donors (HD). Furthermore, a negative correlation between sEV-PDL1 and CD8+T cell was observed. sEV-PDL1 induced CD8+T cell exhaustion by reducing the expression levels of Ki67, Granzyme B (GrzmB), and interferon-γ (IFN-γ) both in vitro and in vivo. However, anti-PDL1 reversed the result. Our findings reveal that targeting sEV-PDL1 to rejuvenate CD8+T cell functions is one of the mechnisms a promising therapeutic strategy for ESCC.

Exosomes as a Therapeutic Strategy in Cancer: Potential Roles as Drug Carriers and Immune Modulators

Exosome-based cancer immunotherapy is advancing quickly on the concept of artificially activating the immune system to combat cancer. They can mechanistically change the tumor microenvironment, increase immune responses, and function as efficient drug delivery vehicles because of their inherent bioactivity, low toxicity, and immunogenicity. Accurate identification of the mechanisms of action of exosomes in tumor environments, along with optimization of their isolation, purification, and characterization methods, is necessary to increase clinical applications. Exosomes can be modified through cargo loading and surface modification to enhance their therapeutic applications, either before or after the donor cells' isolation. These engineered exosomes can directly target tumor cells at the tumor site or indirectly activate innate and adaptive immune responses in the tumor microenvironment. This approach is particularly effective when combined with traditional cancer immunotherapy techniques such as vaccines, immune checkpoints, and CAR-T cells. It can improve anti-tumor responses, induce long-term immunity, and address the limitations of traditional therapies, such as poor penetration in solid tumors and immunosuppressive environments. This review aims to provide a comprehensive and detailed overview of the direct role of engineered exosomes as drug delivery systems and their immunomodulatory effects on tumors as an indirect approach to fighting cancer. Additionally, it will discuss novel immunotherapy options.

Prominosomes - a particular class of extracellular vesicles containing prominin-1/CD133?

Extracellular membrane vesicles (EVs) offer promising values in various medical fields, e.g., as biomarkers in liquid biopsies or as native (or bioengineered) biological nanocarriers in tissue engineering, regenerative medicine and cancer therapy. Based on their cellular origin EVs can vary considerably in composition and diameter. Cell biological studies on mammalian prominin-1, a cholesterol-binding membrane glycoprotein, have helped to reveal new donor membranes as sources of EVs. For instance, small EVs can originate from microvilli and primary cilia, while large EVs might be produced by transient structures such as retracting cellular extremities of cancer cells during the mitotic rounding process, and the midbody at the end of cytokinesis. Here, we will highlight the various subcellular origins of prominin-1+ EVs, also called prominosomes, and the potential mechanism(s) regulating their formation. We will further discuss the molecular and cellular characteristics of prominin-1, notably those that have a direct effect on the release of prominin-1+ EVs, a process that might be directly implicated in donor cell reprogramming of stem and cancer stem cells. Prominin-1+ EVs also mediate intercellular communication during embryonic development and adult homeostasis in healthy individuals, while disseminating biological information during diseases.

Unlocking the secrets of the immunopeptidome: MHC molecules, ncRNA peptides, and vesicles in immune response

The immunopeptidome, a diverse set of peptides presented by Major Histocompatibility Complex (MHC) molecules, is a critical component of immune recognition and response. This review article delves into the mechanisms of peptide presentation by MHC molecules, particularly emphasizing the roles of ncRNA-derived peptides and extracellular vesicles (EVs) in shaping the immunopeptidome landscape. We explore established and emerging insights into MHC molecule interactions with peptides, including the dynamics of peptide loading, transport, and the influence of cellular and genetic variations. The article highlights novel research on non-coding RNA (ncRNA)-derived peptides, which challenge conventional views of antigen processing and presentation and the role of EVs in transporting these peptides, thereby modulating immune responses at remote body sites. This novel research not only challenges conventional views but also opens up new avenues for understanding immune responses. Furthermore, we discuss the implications of these mechanisms in developing therapeutic strategies, particularly for cancer immunotherapy. By conducting a comprehensive analysis of current literature and advanced methodologies in immunopeptidomics, this review aims to deepen the understanding of the complex interplay between MHC peptide presentation and the immune system, offering new perspectives on potential diagnostic and therapeutic applications. Additionally, the interactions between ncRNA-derived peptides and EVs provide a mechanism for the enhanced surface presentation of these peptides and highlight a novel pathway for their systemic distribution, potentially altering immune surveillance and therapeutic landscapes.

A game of hide-and-seek: how extracellular vesicles evade the immune system

Extracellular vesicles (EVs) are heterogeneously sized, cell-derived nanoparticles operating as proficient mediators of intercellular communication. They are produced by normal as well as diseased cells and carry a variety of cargo. While the molecular details of EV biology have been worked out over the past two decades, one question that continues to intrigue many is how are EVs able to evade the phagocytic immune cells while also being effectively internalized by the target cell or tissue. While some of the components that facilitate this process have started to be identified, many mechanisms are yet to be dissected. This review summarises some of the key mechanisms that cancer cell-derived and viral infected cell-derived EVs utilize to evade the immune system. It will discuss the diverse cloaking mechanisms, in the form of membrane proteins and cargo content that these EVs utilize to enhance pathogenesis. Further, it will highlight the different strategies that have been used to design EVs to escape the immune system, thereby increasing their circulation time with no major toxic effects in vivo. An understanding of the potential EV components that allow better immune evasion can be used to bioengineer EVs with better circulation times for therapeutic purposes.

Exosomes: Key Messengers Mediating the Interaction Between Tumor Cells and CD8+ T Cells in the Tumor Microenvironment

In recent years, with an increasingly profound comprehension of the tumor microenvironment, it has been discovered that the constituent cells within the immune microenvironment, such as macrophages, CD4+T cells, and CD8+T cells, interact with tumor cells in manners conducive to tumorigenesis and progression. Exosomes play a pivotal role as essential mediators for intercellular material exchange and signal transmission in this context. Tumor cell-derived exosomes carrying cargo such as PD-L1 and ncRNAs engage with CD8+T cells to induce cytotoxic responses and facilitate immune evasion, thereby promoting tumor advancement. When combined with current immune checkpoint inhibitors like anti-PD-L1/PD-1 therapy, enhancing CD8+T cell function through exosomal pathways while monitoring and augmenting therapeutic effects can significantly improve efficacy. This review delineates the crucial role of exosomes derived from both tumor cells and CD8+T cells within the tumor microenvironment along with their impact mechanisms on both tumor cells and CD8+T cells. Furthermore, it summarizes the potential for clinical treatment in this realm when integrated with existing immunotherapy methods-particularly exploring the feasibility of clinical translation alongside engineering materials science techniques.

TGFBR2 High mesenchymal glioma stem cells phenocopy regulatory T cells to suppress CD4+ and CD8+ T cell function

Attempts to activate an anti-tumor immune response in glioblastoma (GBM) have been met with many challenges due to its inherently immunosuppressive tumor microenvironment. The degree and mechanisms by which molecularly and phenotypically diverse tumor-propagating glioma stem cells (GSCs) contribute to this state are poorly defined. In this study, our multifaceted approach combining bioinformatics analyses of clinical and experimental datasets, single-cell sequencing, and molecular and pharmacologic manipulation of patient-derived cells identified GSCs expressing immunosuppressive effectors mimicking regulatory T cells (Tregs). We show that this I mmunosuppressive T reg- L ike (ITL) GSC state is specific to the mesenchymal GSC subset and is associated with and driven specifically by TGF-β type II receptor (TGFBR2) in contrast to TGFBR1. Transgenic TGFBR2 expression in patient-derived GBM neurospheres promoted a mesenchymal transition and induced a 6-gene ITL signature consisting of CD274 (PD-L1), NT5E (CD73), ENTPD1 (CD39), LGALS1 (galectin-1), PDCD1LG2 (PD-L2), and TGFB1. This TGFBR2-driven ITL signature was identified in clinical GBM specimens, patient-derived GSCs and systemic mesenchymal malignancies. TGFBR2 High GSCs inhibited CD4+ and CD8+ T cell viability and their capacity to kill GBM cells, effects reversed by pharmacologic and shRNA-based TGFBR2 inhibition. Collectively, our data identify an immunosuppressive GSC state that is TGFBR2-dependent and susceptible to TGFBR2-targeted therapeutics.

Comprehensive Potential of Artificial Intelligence for Predicting PD-L1 Expression and EGFR Mutations in Lung Cancer: A Systematic Review and Meta-Analysis

OBJECTIVE

To evaluate the methodological quality and the predictive performance of artificial intelligence (AI) for predicting programmed death ligand 1 (PD-L1) expression and epidermal growth factor receptors (EGFR) mutations in lung cancer (LC) based on systematic review and meta-analysis.

METHODS

AI studies based on PET/CT, CT, PET, and immunohistochemistry (IHC)-whole-slide image (WSI) were included to predict PD-L1 expression or EGFR mutations in LC. The modified Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool was used to evaluate the methodological quality. A comprehensive meta-analysis was conducted to analyze the overall area under the curve (AUC). The Cochrane diagnostic test and I2 statistics were used to assess the heterogeneity of the meta-analysis.

RESULTS

A total of 45 AI studies were included, of which 10 were used to predict PD-L1 expression and 35 were used to predict EGFR mutations. Based on the analysis using the QUADAS-2 tool, 37 studies achieved a high-quality score of 7. In the meta-analysis of PD-L1 expression levels, the overall AUCs for PET/CT, CT, and IHC-WSI were 0.80 (95% confidence interval [CI], 0.77-0.84), 0.74 (95% CI, 0.69-0.77), and 0.95 (95% CI, 0.93-0.97), respectively. For EGFR mutation status, the overall AUCs for PET/CT, CT, and PET were 0.85 (95% CI, 0.81-0.88), 0.83 (95% CI, 0.80-0.86), and 0.75 (95% CI, 0.71-0.79), respectively. The Cochrane Diagnostic Test revealed an I2 value exceeding 50%, indicating substantial heterogeneity in the PD-L1 and EGFR meta-analyses. When AI was combined with clinicopathological features, the enhancement in predicting PD-L1 expression was not substantial, whereas the prediction of EGFR mutations showed improvement compared to the CT and PET models, albeit not significantly so compared to the PET/CT models.

CONCLUSIONS

The overall performance of AI in predicting PD-L1 expression and EGFR mutations in LC has promising clinical implications.

Biological Cargo: Exosomes and their Role in Cancer Progression and Metastasis

Cancer cells are among the many types of cells that release exosomes, which are nanovesicles. Because of their many potential applications, exosomes have recently garnered much attention from cancer researchers. The bioactive substances that exosomes release as cargo have been the subject of several investigations. The substances in question may operate as biomarkers for diagnosis or affect apoptosis, the immune system, the development and spread of cancer, and other processes. Others have begun to look at exosomes in experimental therapeutic trials because they believe they may be useful in the treatment of cancer. This review started with a short description of exosome biogenesis and key features. Next, the potential of tumor-derived exosomes and oncosomes to influence the immune system throughout the development of cancer, as well as alter tumor microenvironments (TMEs) and pre-metastatic niche creation, was investigated. Finally, there was talk of exosomes' possible use in cancer treatment. Furthermore, there is emerging consensus about the potential application of exosomes to be biological reprogrammers of cancer cells, either as carriers of naturally occurring chemicals, including anticancer medications, or as carriers of anticancer vaccines for immunotherapy as well as boron neutron capture therapy (BNCT). We briefly review the key ideas and logic behind this intriguing therapy recommendation.

Distinct roles of small extracellular vesicles from resident and infiltrating macrophages on glioma growth and mobility

Previous studies revealed that tumor-associated macrophages/microglia (TAMs) promoted glioma invasiveness during tumor progression and after radiotherapy. However, the communication of TAMs with tumor cells remains unclear. This study aimed to examine the role of small extracellular vesicles (sEVs) derived from TAMs in TAMs-mediated brain tumor invasion. This study utilized BV2 and RAW264.7 cell lines representing resident and infiltrating macrophages, respectively, to unveil their effect on tumor cells. Purified sEVs from BV2 and RAW264.7 were validated by nanoparticle track analysis (NTA), transmission electron microscopy (TEM), and western blotting for sEV markers. The effect of sEVs on the murine astrocytoma tumor cell line ALTS1C1 was examined on cell proliferation, migration, and gene expression. The results showed that ALTS1C1 cells effectively engulfed sEVs purified from BV2 and RAW264.7. Only BV2-derived sEVs promoted cell proliferation and were dose-dependent. Further, morphological changes in ALTS1C1 cells were observed after incubation with BV2-derived sEVs, which was associated with enhancing cell migration. BV2-mediated glioma proliferation and mobility were related to the upregulation of vascular endothelial growth factor (VEGF) and downregulation of death effector domain-containing protein (DEDD) gene expression. This study demonstrates the distinct function of sEVs of resident macrophages on glioma cell invasion and reveals the mechanism underlying microglia-mediated tumor progression. These findings suggested resident microglia is the potential therapeutic target for TAMs-induced brain tumor invasiveness.

Extracellular Vesicles from Plasma of Patients with Glioblastoma Promote Invasion of Glioblastoma Cells Even After Tumor Resection

Background: Glioblastoma (GB) is a highly aggressive tumor, whose progression is mediated by secretion of extracellular vesicles (EVs), which can pass the brain-blood barrier and be found in the plasma. Here, we performed a comparative analysis of the effects of EVs from the plasma of healthy donors (hEVs) and GB patients before (bEVs) and after (aEVs) tumor surgical resection on invasion of normal astrocytes and GB cells. Methods: We performed the transwell invasion assay, analyzed MAP kinases activation by Western blotting, studied SNAI1/SNAI2 cellular localization by confocal microscopy, measured cadherins expression by flow cytometry, and analyzed secretion of cytokines, which regulate migration and inflammation, by immunoassay. Results: hEVs did not affect invasion of astrocytes and GB cells, there was down-regulated cadherins expression in astrocytes, while there was increased E- and N-cadherin expression in GB cells. hEVs increased the secretion of inflammation and adhesion regulators both in astrocytes and GB cells. bEVs enhanced the invasion of GB cells but not of astrocytes via MAP AKT, JNK1/2/3, and p38 kinases activation, stimulated the clasterization of SNAI1 in the GB cell nucleus, promoted an E/N cadherin switch, and caused the secretion of inflammation and adhesion regulators in astrocytes and GB cells. aEVs exhibited the most of pro-oncogenic effects of bEVs (stimulation of GB cell invasion, SNAI1 nuclear localization, JNK1/2/3 activation, E/N cadherin switch, and secretion of inflammation and adhesion regulators in astrocytes and GB cells). However, aEVs effects were less pronounced than those of bEVs. Conclusions: In our study, we revealed common and different effects of plasma-derived hEVs, aEVs, and bEVs. hEVs can stimulate some pro-oncogenic effects in GB cells. Being less tumorigenic then bEVs, aEVs are still able to promote invasion of GB cells, probably remaining after tumor resection.

Histone deacetylase inhibition disrupts the molecular signature of the glioblastoma secretome related to extracellular vesicle-associated proteins and targets RAB7a and RAB14 in vitro

Glioblastoma (GBM) is the most aggressive brain tumor with a poor prognosis. While Histone Deacetylase inhibitors have shown promising results in inhibiting cancer cell invasion and promoting apoptosis, their effects on GBM secretion, specifically focusing on extracellular vesicles (EVs) secretion, remain largely unexplored. Using label-free NANOLC-MS/MS methodology, we identified significant changes in the abundance of membrane traffic regulatory proteins in the secretome of U87MG cells after the treatment with the HDAC inhibitor Trichostatin A (TSA). In silico analysis showed that TSA treatment disrupted the secretion pattern of EVs-associated proteins and cellular signaling pathways, both qualitatively and quantitatively. Notably, RAB14/RAB7a interaction was only observed in the secretome of cells treated with TSA. In vitro assays revealed that TSA treatment of glioma cells increased EVs secretion and intracellular protein levels of RAB7a and RAB14 without affecting gene expression, suggesting a role of these two EVs-associated proteins in grade IV glioma cells. Additionally, an integrative approach using clinical data highlighted a correlation between DNA mutations affecting vesicle traffic coding-genes and clinical and phenotypic outcomes in glioma patients. These findings provide insights into the interplay between epigenetics and GBM intracellular trafficking, potentially leading to improved strategies for targeting and modifying the complex signaling network established between GBM cells and the tumor cell microenvironment.

Tumour-derived small extracellular vesicles act as a barrier to therapeutic nanoparticle delivery

Nanoparticles are promising for drug delivery applications, with several clinically approved products. However, attaining high nanoparticle accumulation in solid tumours remains challenging. Here we show that tumour cell-derived small extracellular vesicles (sEVs) block nanoparticle delivery to tumours, unveiling another barrier to nanoparticle-based tumour therapy. Tumour cells secrete large amounts of sEVs in the tumour microenvironment, which then bind to nanoparticles entering tumour tissue and traffic them to liver Kupffer cells for degradation. Knockdown of Rab27a, a gene that controls sEV secretion, decreases sEV levels and improves nanoparticle accumulation in tumour tissue. The therapeutic efficacy of messenger RNAs encoding tumour suppressing and proinflammatory proteins is greatly improved when co-encapsulated with Rab27a small interfering RNA in lipid nanoparticles. Together, our results demonstrate that tumour cell-derived sEVs act as a defence system against nanoparticle tumour delivery and that this system may be a potential target for improving nanoparticle-based tumour therapies.

Extracellular vesicles versus lipid nanoparticles for the delivery of nucleic acids

Extracellular vesicles (EVs) are increasingly investigated for delivering nucleic acid (NA) therapeutics, leveraging their natural role in transporting NA and protein-based cargo in cell-to-cell signaling. Their synthetic counterparts, lipid nanoparticles (LNPs), have been developed over the past decades as NA carriers, culminating in the approval of several marketed formulations such as patisiran/Onpattro® and the mRNA-1273/BNT162 COVID-19 vaccines. The success of LNPs has sparked efforts to develop innovative technologies to target extrahepatic organs, and to deliver novel therapeutic modalities, such as tools for in vivo gene editing. Fueled by the recent advancements in both fields, this review aims to provide a comprehensive overview of the basic characteristics of EV and LNP-based NA delivery systems, from EV biogenesis to structural properties of LNPs. It addresses the primary challenges encountered in utilizing these nanocarriers from a drug formulation and delivery perspective. Additionally, biodistribution profiles, in vitro and in vivo transfection outcomes, as well as their status in clinical trials are compared. Overall, this review provides insights into promising research avenues and potential dead ends for EV and LNP-based NA delivery systems.

The roles of extracellular vesicles in gliomas: Challenge or opportunity?

Gliomas are increasingly becoming a major disease affecting human health, and current treatments are not as effective as expected. Deeper insights into glioma heterogeneity and the search for new diagnostic and therapeutic strategies appear to be urgent. Gliomas adapt to their surroundings and form a supportive tumor microenvironment (TME). Glioma cells will communicate with the surrounding cells through extracellular vesicles (EVs) carrying bioactive substances such as nucleic acids, proteins and lipids which is related to the modification to various metabolic pathways and regulation of biological behaviors, and this regulation can be bidirectional, widely existing between cells in the TME, constituting a complex network of interactions. This complex regulation can affect glioma therapy, leading to different types of resistance. Because of the feasibility of EVs isolation in various body fluids, they have a promising usage in the diagnosis and monitoring of gliomas. At the same time, the nature of EVs to cross the blood-brain barrier (BBB) confers potential for their use as drug delivery systems. In this review, we will focus on the roles and functions of EVs derived from different cellular origins in the glioma microenvironment and the intercellular regulatory networks, and explore possible clinical applications in glioma diagnosis and precision therapy.

Combining antimiR-25 and cGAMP Nanocomplexes Enhances Immune Responses via M2 Macrophage Reprogramming

Glioblastoma (GBM) is an aggressive brain cancer with a highly immunosuppressive tumor microenvironment (TME), invariably infiltrated by tumor-associated macrophages (TAMs). These TAMs resemble M2 macrophages, which promote tumor growth and suppress immune responses. GBM cells secrete extracellular vesicles (EVs) containing microRNA-25, which inhibits the cGAS-STING pathway and prevents TAMs from adopting a pro-inflammatory M1 phenotype. This study characterizes antimiR-25/cGAMP nanocomplexes (NCs) for potential therapeutic applications. A particle size analysis revealed a significant reduction upon complexation with antimiR-25, resulting in smaller, more stable nanoparticles. Stability tests across pH levels (4-6) and temperatures (25-37 °C) demonstrated their resilience in various biological environments. Biological assays showed that antimiR-25 NCs interacted strongly with transferrin (Tf), suggesting potential for blood-brain barrier passage. The use of cGAMP NCs activated the cGAS-STING pathway in macrophages, leading to increased type I IFN (IFN-β) production and promoting a shift from the M2 to M1 phenotype. The combined use of cGAMP and antimiR-25 NCs also increased the expression of markers involved in M1 polarization. These findings offer insights into optimizing antimiR-25/cGAMP NCs for enhancing immune responses in GBM.

TERT Gene Mutation in Gliomas Cross-Linked With (NTRK, PDL1, ALK, IDH, P53, EGFR, HER2): A Integrative Review TERT Gene Mutation in Gliomas

INTRODUCTION

Recent advancements in glioma treatment are largely driven by the identification of genetic alterations, which enhance diagnostic precision and prognostic assessments, and unveil potential therapeutic targets. TERT promoter mutations, in particular, are associated with a poorer prognosis and aggressive clinical behavior.

METHODOLOGY

This study explores the genetic interplay between TERT and other genes (ntrk, pdl1, alk, idh, p53, egfr, her2) in brain tumors through an integrative literature review. This method synthesizes evidence from selected articles spanning 2014 to 2023.

RESULTS

The review identified 65 articles based on defined inclusion criteria, out of which 14 were analyzed in depth. Findings reveal that TERT, TP53, and IDH1 are the most frequently mutated genes in gliomas. The prognosis of glioma patients can be refined through the combined analysis of IDH and TERT mutations. Additionally, PD-L1 expression levels are associated with prognosis and may influence treatment responses, particularly, in immunotherapy.

DISCUSSION

The study underscores the importance of molecular diagnostics, such as Next-Generation Sequencing (NGS), in detecting key genetic mutations. These advancements have paved the way for new therapeutic strategies and better patient outcomes. The findings highlight the crucial role of genetic markers in glioma treatment and prognosis, advocating for continued research to enhance clinical applications and patient care.

CONCLUSION

The use of NGS is indispensable in identifying biomarkers associated with mutations in the TERT gene.

Expression, regulation, and function of PD-L1 on non-tumor cells in the tumor microenvironment

Antiprogrammed death ligand 1 (PD-L1) therapy is a leading immunotherapy, but only some patients with solid cancers benefit. Overwhelming evidence has revealed that PD-L1 is expressed on various immune cells in the tumor microenvironment (TME), including macrophages, dendritic cells, and regulatory T cells, modulating tumor immunity and influencing tumor progression. PD-L1 can also be located on tumor cell membranes as well as in exosomes and cytoplasm. Accordingly, the dynamic expression and various forms of PD-L1 might explain the therapy's limited efficacy and resistance. Herein a systematic summary of the expression of PD-L1 on different immune cells and their regulatory mechanisms is provided to offer a solid foundation for future studies.

Tuning a bioengineered hydrogel for studying astrocyte reactivity in glioblastoma

Astrocytes play many essential roles in the central nervous system (CNS) and are altered significantly in disease. These reactive astrocytes contribute to neuroinflammation and disease progression in many pathologies, including glioblastoma (GB), an aggressive form of brain cancer. Current in vitro platforms do not allow for accurate modeling of reactive astrocytes. In this study, we sought to engineer a simple bioengineered hydrogel platform that would support the growth of primary human astrocytes and allow for accurate analysis of various reactive states. After validating this platform using morphological analysis and qPCR, we then used the platform to begin investigating how astrocytes respond to GB derived extracellular vesicles (EVs) and soluble factors (SF). These studies reveal that EVs and SFs induce distinct astrocytic states. In future studies, this platform can be used to study how astrocytes transform the tumor microenvironment in GB and other diseases of the CNS. STATEMENT OF SIGNIFICANCE: Recent work has shown that astrocytes help maintain brain homeostasis and may contribute to disease progression in diseases such as glioblastoma (GB), a deadly primary brain cancer. In vitro models allow researchers to study basic mechanisms of astrocyte biology in healthy and diseased conditions, however current in vitro systems do not accurately mimic the native brain microenvironment. In this study, we show that our hydrogel system supports primary human astrocyte culture with an accurate phenotype and allows us to study how astrocytes change in response to a variety of inflammatory signals in GB. This platform could be used further investigate astrocyte behavior and possible therapeutics that target reactive astrocytes in GB and other brain diseases.

Exosome therapeutics for non-small cell lung cancer tumorigenesis

Non-small cell lung cancer (NSCLC) remains an ongoing health concern, with poor treatment options and prognosis for many patients. Typically, individuals with lung cancer are detected at the middle and terminal stages, resulting in poor medical results due to lack of initial diagnosis and treatment. So, finding the initial specific and effective therapy options for lung cancer is necessary. In addition, exosomes are generally small lipid vesicles with a diameter in the nanometer range that are created and released by different cell types. Exosomes have therapeutic potential through delivering bioactive compounds including microRNAs, siRNAs, and therapeutic proteins to tumor cells, modifying the tumor microenvironment, and promoting anti-tumor immune responses. In recent years, exosome-based therapy has become known as an appropriate approach for NSCLC treatment. This review offers an overview of the possibility of exosome-based therapy for NSCLC, with an emphasis on mechanisms of action, preclinical research, and current clinical trials. Preclinical studies have shown that exosome-based therapy can decrease tumor growth, metastasis, and drug resistance in NSCLC models. Furthermore, ongoing clinical trials are looking at the safety and efficacy of exosome-based therapies in NSCLC patients, offering important insights into their translational prospects. Despite promising preclinical evidences, significant obstacles remain, including optimizing exosome isolation and purification techniques, standardizing production strategies, and developing scalable manufacturing processes. Overall, exosome-based therapy shows significant promise as a novel and various methods for treating NSCLC, with the potential to enhance patient outcomes and evolution cancer treatment.

Extracellular vesicles in cancer: golden goose or Trojan horse

Intercellular communication can be mediated by direct cell-to-cell contact and indirect interactions through secretion of soluble chemokines, cytokines, and growth factors. Extracellular vesicles (EVs) have emerged as important mediators of cell-to-cell and cell-to-environment communications. EVs from tumor cells, immune cells, and stromal cells can remodel the tumor microenvironment and promote cancer cell survival, proliferation, metastasis, immune evasion, and therapeutic resistance. Most importantly, EVs as natural nanoparticles can be manipulated to serve as a potent delivery system for targeted cancer therapy. EVs can be engineered or modified to improve their ability to target tumors and deliver therapeutic substances, such as chemotherapeutic drugs, nucleic acids, and proteins, for the treatment of cancer. This review provides an overview of the biogenesis and recycling of EVs, discusses their roles in cancer development, and highlights their potential as a delivery system for targeted cancer therapy.

Investigating nano-sized tumor-derived extracellular vesicles in enhancing anti-PD-1 immunotherapy

Anti-PD1 immune checkpoint blockade (ICB) has shown promising results for treating several aggressive cancers, enhancing patient survival rates. The variability in clinical response to anti-PD1 ICB is thought to be driven by patient-specific biology and heterogeneity within the tumor microenvironment. Tumor-derived extracellular vesicles (TDEVs), nano-sized particles released from tumor cells, can modulate the tumor microenvironment, leading to immunosuppression and tumor progression. Hence, TDEVs may contribute to the variability in treatment response and play a crucial role in the failure of anti-PD1 immunotherapy. In this study, we develop a systems biology approach to interrogate the role of TDEVs on the response dynamics for anti-PD1 blockade. Our results suggest that the detection and profiling of TDEVs can help screen patients for anti-PD-1 immunotherapy. Moreover, the results in this study suggest that TDEVs and IL-12 can potentially be liquid biopsy biomarkers to profile patient response to anti-PD1 ICB and tailor patient-specific treatment protocols. Importantly, the methodology is generalizable to other types of cancer immunotherapies. Therefore, the collection of patient-specific liquid biopsy data, and the implementation of those data into the systems biology framework, may offer the opportunity to discover new biomarkers for patient drug screening and enable the continuous monitoring of patient response to treatment and adaptation of patient-specific immunotherapy treatment protocols to overcome therapeutic resistance.

Exosomal PDL1 Suppresses the Anticancer Activity of CD8+ T Cells in Hepatocellular Carcinoma

Tumor microenvironment (TME) is essential for the development and progression of hepatocellular carcinoma (HCC). Exosomes participate in constructing TME by passing biological information, but the regulatory effect of PDL1 in exosomes on anticancer activity of CD8+ T cells in HCC still needs to be further explored. In this study, high level of PDL1 was found in plasma exosomes of HCC patients, which turned out to be significantly associated with the increased number of tumor nodules, the upregulated level of serum AFP, the raised tendency of TNM stage, and the poor prognosis of HCC. The expression of CD8 may be inhibited in HCC that is characterized with high level of PDL1, and the protein level of exosomal PDL1 was determined by intracellular PDL1 abundance. High level of exosomal PDL1 inhibited the proliferation and activation of CD8+ T cells, but exhibited limited effect on the proliferation of hepatic cancer cells. Moreover, the growth of tumors formed by hepatic cancer cells Hepa1-6 in C57L mice was significantly promoted by the exosomal PDL1, which might be caused by the inhibitory effect of exosomal PDL1 on CD8+ T cells. Thus, exosomal PDL1 promotes the development and progression of HCC through inhibiting the anticancer activity of CD8+ T cells. This study provides sights for understanding the oncogenic role of PDL1 and a reasonable explanation for the low efficacy of anti-PD1/PDL1 immunotherapies in HCC.

High-throughput screening identifies ibuprofen as an sEV PD-L1 inhibitor for synergistic cancer immunotherapy

Programmed death-ligand 1 (PD-L1) on tumor-derived small extracellular vesicles (sEVs) limits therapeutic effectiveness by interacting with the PD-1 receptor on host immune cells. Targeting the secretion of sEV PD-L1 has emerged as a promising strategy to enhance immunotherapy. However, the lack of small-molecule inhibitors poses a challenge for clinical translation. In this study, we developed a target and phenotype dual-driven high-throughput screening strategy that combined virtual screening with nanoflow-based experimental verification. We identified ibuprofen (IBP) as a novel inhibitor that effectively targeted sEV PD-L1 secretion. IBP disrupted the biogenesis and secretion of PD-L1+ sEVs in tumor cells by physically interacting with a critical regulator of sEV biogenesis, hepatocyte growth factor-regulated tyrosine kinase substrate. Notably, the mechanism of action of IBP is distinct from its commonly known targets, cyclooxygenases. Administration of IBP stimulated antitumor immunity and enhanced the efficacy of anti-PD-1 therapy in melanoma and oral squamous cell carcinoma mouse models. To address potential adverse effects, we further developed an IBP gel for topical application, which demonstrated remarkable therapeutic efficacy when combined with anti-PD-1 treatment. The discovery of this specific small inhibitor provides a promising avenue for establishing durable, systemic antitumor immunity.

Rapid Assessment of Biomarkers on Single Extracellular Vesicles Using "Catch and Display" on Ultrathin Nanoporous Silicon Nitride Membranes

Extracellular vesicles (EVs) are particles released from cells that facilitate intercellular communication and have tremendous diagnostic and therapeutic potential. Bulk assays lack the sensitivity to detect rare EV subsets relevant to disease, and while single EV analysis techniques remedy this, they are often undermined by complicated detection schemes and prohibitive instrumentation. To address these issues, a microfluidic technique for EV characterization called "catch and display for liquid biopsy (CAD-LB)" is proposed. In this method, minimally processed samples are pipette-injected and fluorescently labeled EVs are captured in the nanopores of an ultrathin membrane.  This enables the rapid assessment of EV number and biomarker colocalization by light microscopy. Here, nanoparticles are used to define the accuracy and dynamic range for counting and colocalization. The same assessments are then made for purified EVs and for unpurified EVs in plasma. Biomarker detection is validated using CD9 and Western blot analysis to confirm that CAD-LB accurately reports relative protein expression levels. Using unprocessed conditioned media, CAD-LB captures the known increase in EV-associated ICAM-1 following endothelial cell cytokine stimulation. Finally, to demonstrate CAD-LB's clinical potential, EV biomarkers indicative of immunotherapy responsiveness are successfully detected in the plasma of bladder cancer patients treated with immune checkpoint blockade.

Novel insights into the regulation of exosomal PD-L1 in cancer: From generation to clinical application

Programmed cell death ligand 1 (PD-L1) interacts with programmed cell death 1 (PD-1), leading to T cell exhaustion and promoting tumor cell survival, ultimately mediating immunosuppression. While FDA-approved monoclonal antibodies targeting the PD-1/PD-L1 interaction have shown success in cancer treatment, some patients experience limited and short-lived therapeutic outcomes. Recent studies have identified PD-L1 expression not only on tumor cell surfaces but also on exosomes, with secretion pathways including both conventional and unconventional endocytosis routes, presenting a unique therapeutic opportunity. Emerging evidence suggests that exosomal PD-L1 contributes to systemic immunosuppression, potentially counteracting the effects of anti-PD-1 checkpoint therapies. However, the significance of exosomal PD-L1 in clinical cancer patients unresponsive to anti-PD-1/PD-L1 immunotherapy, as well as the factors regulating its generation, remain unclear. Moreover, the mechanisms underlying PD-L1 expression on exosomes and its regulation in cancer are yet to be fully elucidated. This review primarily focuses on the mechanisms modulating exosomal PD-L1 generation in cancer, while also outlining its involvement in immunosuppression, tumor proliferation, and response to cancer immunotherapy. Additionally, we explore the potential of exosomal PD-L1 as a cancer biomarker and therapeutic target, aiming to provide a comprehensive overview of this emerging field and its implications for cancer treatment and diagnosis.

Immune checkpoint pathways in glioblastoma: a diverse and evolving landscape

Immune checkpoint (IC) inhibition in glioblastoma (GBM) has not shown promising results in the last decade compared to other solid tumors. Several factors contributing to the lack of immunotherapy response include the profound immunosuppressive nature of GBM, highly redundant signaling pathways underlying immune checkpoints, and the negative immunogenic impact of current standard of care on the tumor microenvironment. In this review, we will discuss various ICs in the context of GBM, their interplay with the tumor immune microenvironment, relevant pre-clinical and clinical studies, and the impact of current treatment modalities on GBM IC blockade therapy. Understanding the molecular mechanisms that drive ICs, and how they contribute to an immunosuppressive tumor microenvironment is critical in advancing IC inhibition therapy in GBM. Furthermore, revisiting current treatment modalities and their impact on the immune landscape is instrumental in designing future combinatorial therapies that may overcome treatment resistance.

DNA Nanomaterial-Empowered Surface Engineering of Extracellular Vesicles

Extracellular vesicles (EVs) are cell-secreted biological nanoparticles that are critical mediators of intercellular communication. They contain diverse bioactive components, which are promising diagnostic biomarkers and therapeutic agents. Their nanosized membrane-bound structures and innate ability to transport functional cargo across major biological barriers make them promising candidates as drug delivery vehicles. However, the complex biology and heterogeneity of EVs pose significant challenges for their controlled and actionable applications in diagnostics and therapeutics. Recently, DNA molecules with high biocompatibility emerge as excellent functional blocks for surface engineering of EVs. The robust Watson-Crick base pairing of DNA molecules and the resulting programmable DNA nanomaterials provide the EV surface with precise structural customization and adjustable physical and chemical properties, creating unprecedented opportunities for EV biomedical applications. This review focuses on the recent advances in the utilization of programmable DNA to engineer EV surfaces. The biology, function, and biomedical applications of EVs are summarized and the state-of-the-art achievements in EV isolation, analysis, and delivery based on DNA nanomaterials are introduced. Finally, the challenges and new frontiers in EV engineering are discussed.

Shedding Light on the Role of Exosomal PD-L1 (ExoPD-L1) in Cancer Progression: an Update

Exosomes are the primary category of extracellular vesicles (EVs), which are lipid-bilayer vesicles with biological activity spontaneously secreted from either normal or tansformed cells. They serve a crucial role for intercellular communication and affect extracellular environment and the immune system. Tumor-derived exosomes (TEXs) enclose high levels of immunosuppressive proteins, including programmed death-ligand 1 (PD-L1). PD-L1 and its receptor PD-1 act as crucial immune checkpoint molecules, thus facilitating tumor advancement by inhibiting immune responses. PDL-1 is abundantly present on tumor cells and interacts with PD-1 on activated T cells, resulting in T cell suppression and allowing immune evasion of cancer cells. Various FDA-approved monoclonal antibodies inhibiting the PD-1/PD-L1 interaction are commonly used to treat a diverse range of tumors. Although the achieved results are significant, some individuals have a poor reaction to PD-1/PD-L1 blocking. PD-L1-enriched TEXs may mimic the impact of cell-surface PD-L1, consequently potentiating tumor resistance to PD1/PD-L1 based therapy. In light of this, a strong correlation between circulating exosomal PD-L1 levels and response rate to anti-PD-1/PD-L1 antibody treatment has been evinced. This article inspects the function of exosomal PDL-1 in developing resistance to anti-PD-1/PD-L1 therapy for opening new avenues for overcoming tumor resistance to such modalities and development of more favored combination therapy.

Prophylaxis with abemaciclib delays tumorigenesis in dMMR mice by altering immune responses and reducing immunosuppressive extracellular vesicle secretion

BACKGROUND

The CDK4/6 inhibitor abemaciclib is an FDA-approved agent and induces T-cell-mediated immunity. Previously, we confirmed the therapeutic potential of abemaciclib on mismatch repair-deficient (dMMR) tumors in mice. Here, we applied a prophylactic administration/dosage setting using two preclinical mouse models of dMMR-driven cancer.

METHODS

Mlh1-/- and Msh2loxP/loxP mice received repeated prophylactic applications of abemaciclib mesylate (75 mg/kg bw, per oral) as monotherapy or were left untreated. Blood phenotyping and multiplex cytokine measurements were performed regularly. The tumor microenvironment was evaluated by immunofluorescence and Nanostring-based gene expression profiling. Numbers, size and immune composition and activity of extracellular vesicles (EVs) were studied at the endpoint.

FINDINGS

Prophylactic abemaciclib-administration delayed tumor development and significantly prolonged overall survival in both mouse strains (Mlh1-/-: 50.0 wks vs. control: 33.9 wks; Msh2loxP/loxP;TgTg(Vil1-cre: 58.4 wks vs. control 44.4 wks). In Mlh1-/- mice, pro-inflammatory cytokines (IL-2, IL-6) significantly increased, whereas IL-10 and IL-17A decreased. Circulating and splenic exhausted and regulatory T cell numbers were significantly lower in the abemaciclib groups. Deeper analysis of late-onset tumors revealed activation of the Hedgehog and Notch signaling in Mlh1-/- mice, and activation of the MAPK pathway in Msh2loxP/loxP;TgTg(Vil1-cre mice. Still, arising tumors had fewer infiltrating myeloid-derived suppressor cells (vs. control). Notably, prophylactic abemaciclib-administration prevented secretion of procoagulant EVs but triggered release of immunomodulatory EVs in Mlh1-/- mice.

INTERPRETATION

Prophylactic abemaciclib prolongs survival via global immunomodulation. Prophylactic use of abemaciclib should be considered further for individuals with inherited dMMR.

FUNDING

This work was supported by grants from the German research foundation [DFG grant number: MA5799/2-2] and the Brigitte und Dr. Konstanze Wegener-Stiftung to CM.