The role of PTRF/Cavin1 as a biomarker in both glioma and serum exosomes

EWI-2 controls nucleocytoplasmic shuttling of EGFR signaling molecules and miRNA sorting in exosomes to inhibit prostate cancer cell metastasis

Early and accurate diagnosis of prostate cancer (PCa) is extremely important, as metastatic PCa remains hard to treat. EWI-2, a member of the Ig protein subfamily, is known to inhibit PCa cell migration. In this study, we found that EWI-2 localized on both the cell membrane and exosomes regulates the distribution of miR-3934-5p between cells and exosomes. Interestingly, we observed that EWI-2 is localized not only on the plasma membrane but also on the nuclear envelope (nuclear membrane), where it regulates the nuclear translocation of signaling molecules and miRNA. Collectively, these functions of EWI-2 found in lipid bilayers appear to regulate PCa cell metastasis through the epidermal growth factor receptor-mitogen-activated protein kinase-extracellular-signal-regulated kinase (EGFR-MAPK-ERK) pathway. Our research provides new insights into the molecular function of EWI-2 on PCa metastasis, and highlights EWI-2 as a potential PCa biomarker.

Targeting HLA-F suppresses the proliferation of glioma cells via a reduction in hexokinase 2-dependent glycolysis

HLA-F, a nonclassical HLA class I molecule, is required for regulating immune tolerance. In recent years, HLA-F has been found to play a role in a variety of cancers, including glioma (GM). Additionally, high expression of HLA-F predicts the poor overall survival of individuals with GM. However, the functions of HLA-F in GM remain to be further elucidated. In this study, we found that HLA-F expression was elevated in GM tissues. High levels of HLA-F resulted in a high cell proliferation index and predicted GM recurrence. Forced expression of HLA-F promoted the growth of murine C8-D1A cells transplanted in immunodeficient Rag2^-/- mice. In contrast, silencing HLA-F inhibited cell growth in vitro. Furthermore, targeting HLA-F with an anti-HLA-F antibody suppressed the growth of C8-D1A cells stably expressing HLA-F transplanted in immunodeficient Rag2^-/- mice. In further experiments, we found that forced expression of HLA-F contributed to the aerobic glycolysis phenotype in C8-D1A cells along with an increase in HK2 protein stabilization. Conversely, silencing HK2 by shRNA reduced HLA-F-mediated glycolysis and cell proliferation. Our data indicated that HLA-F promoted cell proliferation via HK2-dependent glycolysis. HLA-F could be a potential therapeutic target for the treatment of GM.

Secreted Extracellular Vesicle Molecular Cargo as a Novel Liquid Biopsy Diagnostics of Central Nervous System Diseases

Secreted extracellular vesicles (EVs) are heterogeneous cell-derived membranous granules which carry a large diversity of molecules and participate in intercellular communication by transferring these molecules to target cells by endocytosis. In the last decade, EVs’ role in several pathological conditions, from etiology to disease progression or therapy evasion, has been consolidated, including in central nervous system (CNS)-related disorders. For this review, we performed a systematic search of original works published, reporting the presence of molecular components expressed in the CNS via EVs, which have been purified from plasma, serum or cerebrospinal fluid. Our aim is to provide a list of molecular EV components that have been identified from both nonpathological conditions and the most common CNS-related disorders. We discuss the methods used to isolate and enrich EVs from specific CNS-cells and the relevance of its components in each disease context.

Role of Tumor-Derived Extracellular Vesicles in Glioblastoma

Glioblastoma (GBM) is the most common primary central nervous system tumor and one of the most lethal cancers worldwide, with morbidity of 5.26 per 100,000 population per year. These tumors are often associated with poor prognosis and terrible quality of life. Extracellular vesicles (EVs) are membrane-bound nanoparticles secreted by cells and contain lipid, protein, DNA, mRNA, miRNA and other bioactive substances. EVs perform biological functions by binding or horizontal transfer of bioactive substances to target cell receptors. In recent years, EVs have been considered as possible targets for GBM therapy. A great many types of research demonstrated that EVs played a vital role in the GBM microenvironment, development, progression, angiogenesis, invasion, and even the diagnosis of GBM. Nevertheless, the exact molecular mechanisms and roles of EVs in these processes are unclear. It can provide the basis for GBM treatment in the future that clarifying the regulatory mechanism and related signal pathways of EVs derived from GBM and their clinical value in GBM diagnosis and treatment. In this paper, the research progress and clinical application prospects of GBM-derived EVs are reviewed and discussed.

MiR-330-3p and miR-485-5p as biomarkers for glioblastoma: An integrated bioinformatics and experimental study

Glioblastoma Multiforme (GBM) is the most common, invasive, and malignant primary brain tumor with a poor prognosis and a median survival of 12-15 months. This study tried to identify the most significant miRNA biomarkers in both tissue and serum samples of GBM. GSE25632 was employed from gene expression omnibus and using WGCNA package, association of miRNA networks and clinical data was explored and brown and green modules identified as the most relevant modules. Independently, Limma package was utilized to identify differentially expressed miRNAs (DEMs) in GSE25632 by cutoff logFC > 2 and P.value < 0.05. By merging the results of Limma and WGCNA, the miRNAs that were in brown and green modules and had mentioned cutoff were selected as hub miRNAs. Performing enrichment analysis, Pathways in cancer, Prostate cancer, Glioma, p53 signaling pathway, and Focal adhesion were identified as the most important signaling pathways. Based on miRNA- target genes, has-mir-330-3p and has-mir-485-5p were identified as core miRNAs. The expression level of core miRNAs was validated by GSE90604, GSE42657, and GSE93850. We evaluated the expression level of common target genes of two detected core genes based on GSE77043, GSE42656, GSE22891, GSE15824, and GSE122498. The ability of detected miRNAs to discriminate GBM from healthy controls was assessed by area under the curve (AUC) using the ROC curve analysis. Based on TCGA database, we tested the prognostic significance of miRNAs using overall survival analysis. We evaluated the expression level of the miRNAs in tissue of 83 GBM patients and also non-tumoral adjacent (as control) tissues. We used serum samples of 34 GBM patients to evaluate the expression levels of the hub miRNAs compare to the controls. Our results showed that has-mir-330-3p and has-mir-485-5p could be potential biomarkers in GBM.

Plasma Extracellular Vesicle Characteristics Correlate with Tumor Differentiation and Predict Overall Survival in Patients with Pancreatic Ductal Adenocarcinoma Undergoing Surgery with Curative Intent

Better preoperative characterization of patients with pancreatic ductal adenocarcinoma (PDAC) would aid in treatment optimization. Extracellular vesicles (EV) are promising, largely unexplored biomarkers in PDAC. This study aimed to evaluate if plasma EV characteristics are associated with PDAC clinical characteristics and overall survival (OS). The prospective cohort included 34 PDAC patients undergoing surgery with curative intent. Patient data and plasma samples were collected preoperatively, intraoperatively and one month postoperatively. Small plasma EV (sEV) concentration and size were determined by nanoparticle-tracking analysis. A Mann-Whitney test, Spearman's rho and Cox regression were used in statistical analysis. Preoperatively, patients with poorly differentiated tumors had significantly larger plasma sEVs when compared to patients with well/moderately differentiated tumors (mean diameter 176.9 vs. 149.2 nm, p = 0.021), the sEV size even enabling discrimination of the two groups (AUC = 0.742, 95% CI = 0.560-0.923). Plasma sEV characteristics were also a predictor of OS in multivariable analysis. Patients with a more than 33.8% increase in sEV concentration after one month had 7.2 months shorter median OS (p = 0.002), while patients with a more than 28.0% decrease in sEV size had 9.2 months shorter median OS (p = 0.045). Plasma sEV concentration and size correlate with tumor differentiation and may predict OS in PDAC patients. In the future, plasma sEV characteristics could contribute to improved patient stratification for optimized treatment.

Extracellular vesicles derived from hypoxic glioma stem-like cells confer temozolomide resistance on glioblastoma by delivering miR-30b-3p

Rationale: Glioma stem-like cells (GSCs) contribute to temozolomide (TMZ) resistance in gliomas, although the mechanisms have not been delineated. Methods: In vitro functional experiments (colony formation assay, flow cytometric analysis, TUNEL assay) were used to assess the ability of extracellular vesicles (EVs) from hypoxic GSCs to promote TMZ resistance in glioblastoma (GBM) cells. RNA sequencing and quantitative Reverse Transcription-PCR were employed to identify the functional miRNA in hypoxic EVs. Chromatin immunoprecipitation assays were performed to analyze the transcriptional regulation of miRNAs by HIF1α and STAT3. RIP and RNA pull-down assays were used to validate the hnRNPA2B1-mediated packaging of miRNA into EVs. The function of EV miR-30b-3p from hypoxic GSCs was verified by in vivo experiments and analysis of clinical samples. Results: Hypoxic GSC-derived EVs exerted a greater effect on GBM chemoresistance than those from normoxic GSCs. The miRNA profiling revealed that miR-30b-3p was significantly upregulated in the EVs from hypoxic GSCs. Further, HIF1α and STAT3 transcriptionally induced miR-30b-3p expression. RNA immunoprecipitation and RNA-pull down assays revealed that binding of miR-30b-3p with hnRNPA2B1 facilitated its transfer into EVs. EV-packaged miR-30b-3p (EV-miR-30b-3p) directly targeted RHOB, resulting in decreased apoptosis and increased proliferation in vitro and in vivo. Our results provided evidence that miR-30b-3p in CSF could be a potential biomarker predicting resistance to TMZ. Conclusion: Our findings indicated that targeting EV-miR-30b-3p could provide a potential treatment strategy for GBM.

MicroRNA-302a is involved in folate deficiency-induced apoptosis through the AKT-FOXO1-BIM pathway in mouse embryonic stem cells

Background

Our previous study had shown that microRNA (miR)-302a played a key role in folate deficiency-induced apoptosis in mouse embryonic stem cells. However, details regarding the mechanism remain unclear. Transcription factors (TFs) and miRNAs are two key elements in gene regulation. The aim of this study is to construct the TF-miRNA gene regulation network and demonstrate its possible mechanism.

Methods

The TF-miRNA gene regulation network was constructed via bioinformatics methods. Chromatin immuno-coprecipitation PCR was selected to confirm the binding between miR-302a and TF. mRNA and protein levels were detected by Real-time quantitative PCR and western blotting. TargetScan prediction and Dual-Luciferase Reporter Assay system were used to confirm whether the miRNA binded directly to the predicted target gene.

Results

FOXO1 and miR-302a were selected as the key TF and miRNA, respectively. FOXO1 was confirmed to bind directly to the upstream promoter region of miR-302a. Real-time quantitative PCR and immunoblotting showed that in folate-free conditions, miR-302a and AKT were down regulated, while FOXO1 and Bim were up-regulated significantly. Additionally, treatment with LY294002 inhibitor revealed the involvement of the Akt/FOXO1/Bim signaling pathway in folate deficiency-induced apoptosis, rather than the ERK pathway. Finally, TargetScan prediction and double luciferase reporting experiments illustrated the ability of miR-302a to target the Bim 3′UTR region.

Conclusion

The involvement of miR-302a in folate deficiency-induced apoptosis through the AKT-FOXO1-BIM pathway in mESCs is a unique demonstration of the regulation mechanism of nutrient expression in embryonic development.

Role of Exosomes in the Progression, Diagnosis, and Treatment of Gliomas

Gliomas are the most common primary malignant brain tumors associated with a low survival rate. Even after surgery, radiotherapy, and chemotherapy, gliomas still have a poor prognosis. Extracellular vesicles are a heterogeneous group of cell-derived membranous structures. Exosomes are a type of extracellular vesicles, their size ranges from 30 nm to 100 nm. Recent studies have proved that glioma cells could release numerous exosomes; therefore, exosomes have gained increasing attention in glioma-related research.

Recent studies have confirmed the importance of extracellular vesicles, particularly exosomes, in the development of brain tumors, including gliomas. Exosomes mediate intercellular communication in the tumor microenvironment by transporting biomolecules (proteins, lipids, deoxyribonucleic acid, and ribonucleic acid); thereby playing a prominent role in tumor proliferation, differentiation, metastasis, and resistance to chemotherapy or radiation. Given their nanoscale size, exosomes can traverse the blood-brain barrier and promote tumor progression by modifying the tumor microenvironment. Based on their structural and functional characteristics, exosomes are demonstrating their value not only as diagnostic and prognostic markers, but also as tools in therapies specifically targeting glioma cells.

Therefore, exosomes are a promising therapeutic target for the diagnosis, prognosis, and treatment of malignant gliomas. More research will be needed before exosomes can be used in clinical applications. Here, we describe the exosomes, their morphology, and their roles in the diagnosis and progression of gliomas. In addition, we discuss the potential of exosomes as a therapeutic target/drug delivery system for patients with gliomas.

Isolation and characterization of exosomes for cancer research

Exosomes are a subset of extracellular vesicles that carry specific combinations of proteins, nucleic acids, metabolites, and lipids. Mounting evidence suggests that exosomes participate in intercellular communication and act as important molecular vehicles in the regulation of numerous physiological and pathological processes, including cancer development. Exosomes are released by various cell types under both normal and pathological conditions, and they can be found in multiple bodily fluids. Moreover, exosomes carrying a wide variety of important macromolecules provide a window into altered cellular or tissue states. Their presence in biological fluids renders them an attractive, minimally invasive approach for liquid biopsies with potential biomarkers for cancer diagnosis, prediction, and surveillance. Due to their biocompatibility and low immunogenicity and cytotoxicity, exosomes have potential clinical applications in the development of innovative therapeutic approaches. Here, we summarize recent advances in various technologies for exosome isolation for cancer research. We outline the functions of exosomes in regulating tumor metastasis, drug resistance, and immune modulation in the context of cancer development. Finally, we discuss prospects and challenges for the clinical development of exosome-based liquid biopsies and therapeutics.

Caveolae as Potential Hijackable Gates in Cell Communication

Caveolae are membrane microdomains described in many cell types involved in endocytocis, transcytosis, cell signaling, mechanotransduction, and aging. They are found at the interface with the extracellular environment and are structured by caveolin and cavin proteins. Caveolae and caveolins mediate transduction of chemical messages via signaling pathways, as well as non-chemical messages, such as stretching or shear stress. Various pathogens or signals can hijack these gates, leading to infectious, oncogenic and even caveolin-related diseases named caveolinopathies. By contrast, preclinical and clinical research have fallen behind in their attempts to hijack caveolae and caveolins for therapeutic purposes. Caveolae involvement in human disease is not yet fully explored or understood and, of all their scaffold proteins, only caveolin-1 is being considered in clinical trials as a possible biomarker of disease. This review briefly summarizes current knowledge about caveolae cell signaling and raises the hypothesis whether these microdomains could serve as hijackable “gatekeepers” or “gateways” in cell communication. Furthermore, because cell signaling is one of the most dynamic domains in translating data from basic to clinical research, we pay special attention to translation of caveolae, caveolin, and cavin research into clinical practice.

Recent Advances in Immune Cell Therapy for Glioblastoma

Glioblastoma (GBM) is the most malignant form of astrocytoma with short survival and a high recurrence rate and remains a global problem. Currently, surgery, chemotherapy, radiotherapy, and other comprehensive treatments are the main treatment modalities, but patients still have a poor prognosis mainly due to the infiltrative growth of GBM and the protective effect of the blood–brain barrier on tumor cells. Therefore, immunotherapy is expected to be a good option for GBM. In the immune system, different cells play varying roles in the treatment of GBM, so understanding the roles played by various immune cells in treating GBM and considering how to combine these effects to maximize the efficacy of these cells is important for the selection of comprehensive and optimal treatment plans and improving GBM prognosis. Therefore, this study reviews the latest research progress on the role of various types of immune cells in the treatment of GBM.

Exosomes in Gliomas: Biogenesis, Isolation, and Preliminary Applications in Nanomedicine

Exosomes are phospholipid-based particles endogenously produced by both normal and tumor cells. Initially identified as a pathway for shuttling cellular waste, for a long time they were thought to act as “garbage bags”, and only in the past few years have they emerged as a promising drug delivery system. In this review, we provide an overview of the knowledge about exosome architecture and biogenesis and the recent progress in isolation methods. Furthermore, we describe the mechanisms involved in both extra- and intracellular communication with a focus on glioma brain tumors. Glioma is considered a rare disease and is the most prominent aggressive brain malignancy. How exosomes target glial tumoral cells in vivo remains largely unknown. However, they are able to influence numerous physio-pathological aspects. Here, we discuss the role they play in this heterogeneous and complex microenvironment and their potential applications.

PTRF/CAVIN1, regulated by SHC1 through the EGFR pathway, is found in urine exosomes as a potential biomarker of ccRCC

Polymerase I and transcript release factor (PTRF)/Cavin1 regulates RNA polymerase I during transcription and plays a critical role in endocytosis. Abnormal expressions of PTRF were detected in multiple cancers according to increasing research. PTRF has been showed to involve in the formation and secretion of exosomes and can be detected in the exosomes, which suggests that PTRF would be a potential biomarker for diagnosis of clear cell renal cell carcinoma (ccRCC) using urine samples. Approximately 50-90% of ccRCC cases suffered abnormal epidermal growth factor receptor (EGFR), which activates a variety of signaling pathways, including the mitogen-activated protein kinase/extracellular signal-regulated kinase and Phosphoinositide 3-Kinase/Akt pathway. According to bioinformatic analysis of gene expression arrays of kidney clear cell carcinoma from The Cancer Genome Atlas, we found SHC1 was significantly overexpressed in high-grade ccRCC and correlated to poor prognosis, and also SHC1 was annotated in extracellular matrix process, which was regulated by EGFR. Further studies showed that the expression of PTRF was regulated by SHC1 through EGFR-Phosphoinositide 3-Kinase/Akt pathway. PTRF was detected in the exosomes isolated from ccRCC patients' urine and ccRCC cancer cells culture medium. It suggested that the abnormal SHC1-increased PTRF, which is detected in exosomes from urine, would be a potential marker for ccRCC diagnose and treatment.

Role of exosomes in malignant glioma: microRNAs and proteins in pathogenesis and diagnosis

Malignant gliomas are the most common and deadly type of central nervous system tumors. Despite some advances in treatment, the mean survival time remains only about 1.25 years. Even after surgery, radiotherapy and chemotherapy, gliomas still have a poor prognosis. Exosomes are the most common type of extracellular vesicles with a size range of 30 to 100 nm, and can act as carriers of proteins, RNAs, and other bioactive molecules. Exosomes play a key role in tumorigenesis and resistance to chemotherapy or radiation. Recent evidence has shown that exosomal microRNAs (miRNAs) can be detected in the extracellular microenvironment, and can also be transferred from cell to cell via exosome secretion and uptake. Therefore, many recent studies have focused on exosomal miRNAs as important cellular regulators in various physiological and pathological conditions. A variety of exosomal miRNAs have been implicated in the initiation and progression of gliomas, by activating and/or inhibiting different signaling pathways. Exosomal miRNAs could be used as therapeutic agents to modulate different biological processes in gliomas. Exosomal miRNAs derived from mesenchymal stem cells could also be used for glioma treatment. The present review summarizes the exosomal miRNAs that have been implicated in the pathogenesis, diagnosis and treatment of gliomas. Moreover, exosomal proteins could also be involved in glioma pathogenesis. Exosomal miRNAs and proteins could also serve as non-invasive biomarkers for prognosis and disease monitoring. Video Abstract.

Deep Sequencing of Small RNAs from Neurosurgical Extracellular Vesicles Substantiates miR-486-3p as a Circulating Biomarker that Distinguishes Glioblastoma from Lower-Grade Astrocytoma Patients

Extracellular vesicles (EVs) play key roles in glioblastoma (GBM; astrocytoma grade IV) biology and are novel sources of biomarkers. EVs released from GBM tumors can cross the blood-brain-barrier into the periphery carrying GBM molecules, including small non-coding RNA (sncRNA). Biomarkers cargoed in circulating EVs have shown great promise for assessing the molecular state of brain tumors in situ. Neurosurgical aspirate fluids captured during tumor resections are a rich source of GBM-EVs isolated directly from tumor microenvironments. Using density gradient ultracentrifugation, EVs were purified from cavitron ultrasonic surgical aspirate (CUSA) washings from GBM (n = 12) and astrocytoma II-III (GII-III, n = 5) surgeries. The sncRNA contents of surgically captured EVs were profiled using the Illumina^® NextSeq^TM 500 NGS System. Differential expression analysis identified 27 miRNA and 10 piRNA species in GBM relative to GII-III CUSA-EVs. Resolved CUSA-EV sncRNAs could discriminate serum-EV sncRNA profiles from GBM and GII-III patients and healthy controls and 14 miRNAs (including miR-486-3p and miR-106b-3p) and cancer-associated piRNAs (piR_016658, _016659, _020829 and _204090) were also significantly expressed in serum-EVs. Circulating EV markers that correlate with histological, neuroradiographic and clinical parameters will provide objective measures of tumor activity and improve the accuracy of GBM tumor surveillance.

Homotrimer cavin1 interacts with caveolin1 to facilitate tumor growth and activate microglia through extracellular vesicles in glioma

Background: Intercellular communication via extracellular vesicles (EVs) plays a critical role in glioma progression. However, little is known about the precise mechanism regulating EV secretion and function. Our previous study revealed that Cavin1 was positively correlated with malignancy grades of glioma patients, and that overexpressing Cavin1 in glioma cells enhanced the malignancy of nearby glioma cells via EVs.

Methods: The current study used bioinformatics to design a variant Cavin1 (vCavin1) incapable of interacting with Caveolin1, and compared the effects of overexpressing Cavin1 and vCavin1 in glioma cells on EV production and function.

Results: Remarkably, our results indicated that Cavin1 expression enhanced the secretion, uptake, and homing ability of glioma-derived EVs. EVs expressing Cavin1 promoted glioma growth in vitro and in vivo. In addition, Cavin1 expressing murine glioma cells recruited and activated microglia via EVs. However, vCavin1 neither was loaded onto EVs nor altered EV secretion and function.

Conclusion: Our findings suggested that Cavin1-Caveolin1 interaction played a significant role in regulating production and function of glioma-EVs, and may act as a promising therapeutic target in gliomas that express high levels of Cavin1.

ACT001 reduces the expression of PD-L1 by inhibiting the phosphorylation of STAT3 in glioblastoma

ACT001, which is derived from an ancient anti-inflammatory drug, has been shown to cross the blood-brain barrier in preclinical studies and has demonstrated anti-glioblastoma (GBM) activity in clinical trials. However, its pharmacological potential for anti-GBM immune response modulation remains unclear. The chemical structure of ACT001 indicates that it may bind to STAT3 and thus modulate antitumor immune response. Methods: Bioinformatics and immunohistochemistry (IHC) were used to assess STAT3 and PD-L1 expression in gliomas. Western blotting, RT-PCR and immunofluorescence were used to detect PD-L1 and p-STAT3 expression in glioma cells exposed to ACT001. Chromatin immunoprecipitation, an ACT001-Biotin probe, and a dual-luciferase reporter assay were used to detect direct modulation. The in vivo efficacy of ACT001 was evaluated in GL261 murine glioma model. Survival analyses were conducted using the log-rank (Mantel-Cox) test. Results: Bioinformatic analysis of 1,837 samples from 4 public glioma datasets showed that STAT3 mRNA expression was correlated with the degree of malignancy and therapeutic resistance and that STAT3 mRNA expression was related to immunosuppression, leukocyte infiltration, and PD-L1 expression. IHC staining of 53 tissue samples confirmed that relatively high phosphorylated STAT3 and PD-L1 protein expression was associated with a relatively advanced World Health Organization (WHO) glioma grade. Next, we confirmed that ACT001 treatment reduced PD-L1 expression and STAT3 phosphorylation. An ACT001-biotin probe was used to verify that ACT001 bound to STAT3. We also demonstrated that STAT3 bound to the PD-L1 promoter. The inhibition of PD-L1 expression and STAT3 phosphorylation by ACT001 could be rescued by STAT3 overexpression. Additionally, ACT001 inhibited GBM growth and decreased PD-L1 expression in vivo. The expression of the M2 markers CD206 and CD163 was decreased, while that of the antitumor immune markers iNOS and IFNγ was increased by ACT001 in vivo. Conclusion: Our results demonstrate that STAT3 plays a key role in immunosuppression of glioma and is inhibited by ACT001. ACT001 inhibits PD-L1 transcription and modulates anti-tumor immune response in glioma bearing mice. These findings will help us to understand the mechanism of ACT001 in GBM therapy.

Integrated Analysis of RNA-Binding Proteins in Glioma

RNA-binding proteins (RBPs) play important roles in many cancer types. However, RBPs have not been thoroughly and systematically studied in gliomas. Global analysis of the functional impact of RBPs will provide a better understanding of gliomagenesis and new insights into glioma therapy. In this study, we integrated a list of the human RBPs from six sources-Gerstberger, SONAR, Gene Ontology project, Poly(A) binding protein, CARIC, and XRNAX-which covered 4127 proteins with RNA-binding activity. The RNA sequencing data were downloaded from The Cancer Genome Atlas (TCGA) (n = 699) and Chinese Glioma Genome Atlas (CGGA) (n = 325 + 693). We examined the differentially expressed genes (DEGs) using the R package DESeq2, and constructed a weighted gene co-expression network analysis (WGCNA) of RBPs. Furthermore, survival analysis was also performed based on the univariate and multivariate Cox proportional hazards regression models. In the WGCNA analysis, we identified a key module involved in the overall survival (OS) of glioblastomas. Survival analysis revealed eight RBPs (PTRF, FNDC3B, SLC25A43, ZC3H12A, LRRFIP1, HSP90B1, HSPA5, and BNC2) are significantly associated with the survival of glioblastoma patients. Another 693 patients within the CGGA database were used to validate the findings. Additionally, 3564 RBPs were classified into canonical and non-canonical RBPs depending on the domains that they contain, and non-canonical RBPs account for the majority (72.95%). The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that some non-canonical RBPs may have functions in glioma. Finally, we found that the knockdown of non-canonical RBPs, PTRF, or FNDC3B can alone significantly inhibit the proliferation of LN229 and U251 cells. Simultaneously, RNA Immunoprecipitation (RIP) analysis indicated that PTRF may regulate cell growth and death- related pathways to maintain tumor cell growth. In conclusion, our findings presented an integrated view to assess the potential death risks of glioblastoma at a molecular level, based on the expression of RBPs. More importantly, we identified non-canonical RNA-binding proteins PTRF and FNDC3B, showing them to be potential prognostic biomarkers for glioblastoma.

Lessons from cavin-1 deficiency

Caveolae have been implicated in a wide range of critical physiological functions. In the past decade, the dominant role of cavin-1 in caveolae formation has been established, and it has been recognized as another master regulator for caveolae biology. Human patients with cavin-1 mutations develop lipodystrophy and muscular dystrophy and have some major pathological dysfunctions in fat tissue, skeleton muscle, heart, lung and other organs. Cavin-1 deficiency animal models consistently show similar phenotypes. However, the underlying molecular mechanisms remain to be elucidated. Recent studies have suggested many possible pathways, including mechanosensing, stress response, signal transduction, exosome secretion, and potential functions in the nucleus. Many excellent and comprehensive review articles already exist on the topics of caveolae structure formation, caveolins, and their pathophysiological functions. We will focus on recent studies using cavin-1 deficiency models, to summarize the pathophysiological changes in adipose, muscle, and other organs, followed by a summary of mechanistic studies about the roles of cavin-1, which includes caveolae formation, ribosomal RNA transcription, mechanical sensing, stress response, and exosome secretion. Further studies may help to elucidate the exact underlying molecular mechanism to explain the pathological changes observed in cavin-1 deficient human patients and animal models, so potential new therapeutic strategies can be developed.

Lipid Rafts in Exosome Biogenesis

Exosomes (secreted extracellular vesicles formed in the intracellular vesicular transport system) play a crucial role in distant cell-cell communication. Exosomes transfer active forms of various biomolecules; the molecular composition of the exosomal cargo is a result of targeted selection and depends on the type of producer cells. The mechanisms underlying exosome formation and cargo selection are poorly understood. It is believed that there are several pathways for exosome biogenesis, although the questions about their independence and simultaneous coexistence in the cell still remain open. The least studied topic is the recently discovered mechanism of exosome formation associated with lipid rafts, or membrane lipid microdomains. Here, we present modern concepts and basic hypotheses on the mechanisms of exosome biogenesis and secretion and summarize current data on the involvement of lipid rafts and their constituent molecules in these processes. Special attention is paid to the analysis of possible role in the exosome formation of raft-forming proteins of the SPFH family, components of planar rafts, and caveolin, the main component of caveolae.

GOLPH3 Regulates Exosome miRNA Secretion in Glioma Cells

We aimed to examine whether golgi protein GOLPH3 could affect the secretion of glioma cell-derived exosomes. The exosomes were extracted by ultra-centrifugation from the supernatant of U251 and U87 cell cultures and identified by transmission electron microscopy (TEM), Malvern analyzer, and western blot. The quantity of exosomes was examined by measuring the total protein levels and the number of multiple vesicle bodies (MVBs), the source of exosomes. The exosome miRNAs were analyzed by high-throughput sequencing followed by GO and KEGG analysis, and validated by qRT-PCR. GOLPH3 could not affect the total protein levels of exosomes and the number of MVBs. However, we found 149 differentially expressed miRNAs in exosomes between vector and GOLPH3 over-expression group, and 14 miRNAs were only examined in GOLPH3 over-expression cells. The predicted target genes of these miRNAs had functions in binding and catalytic activity, which were enriched in the pathways of endocytosis, RNA transportation, thyroid hormone signaling and miRNAs in cancer. GOLPH3 could not affect the quantity of exosomes, but rather contribute to miRNA expression in exosomes, which may play some functions in the promotion effect of GOLPH3 on glioma development.

Exosomal circular RNA sorting mechanisms and their function in promoting or inhibiting cancer

Exosomes are nanoscale phospholipid bilayer vesicles that can be artificially engineered into vectors for the treatment of cancer. Circular RNA (circRNA), a type of non-coding RNA, has crucial regulatory functions in various aspects of cancer, such as tumorigenesis, apoptosis, proliferation, invasion, metastasis and chemo- and radiotherapeutic resistance, as well as in cancer prognosis. Notably, the exosomal transfer of circRNAs may function to both promote and inhibit cancer. Numerous studies have addressed the importance of circRNAs in cancer and non-coding RNAs (such as microRNAs and long non-coding RNAs) in exosomes. However, little research has focussed on a class of RNAs called exosomal circRNAs. The present review discusses current studies regarding exosomal circRNAs, including their biogenesis and biological functions, their abundance in exosomes and possible sorting mechanisms and their potential roles in both promoting and inhibiting cancer. It is predicted that in the next five years there will be increasing research exploring the functional mechanisms of exosomal circRNA in various diseases, in particular their roles in cancer genesis and progression.

A role for caveola-forming proteins caveolin-1 and CAVIN1 in the pro-invasive response of glioblastoma to osmotic and hydrostatic pressure

In solid tumours, elevated interstitial fluid pressure (osmotic and hydrostatic pressure) is a barrier to drug delivery and correlates with poor prognosis. Glioblastoma (GBM) further experience compressive force when growing within a space limited by the skull. Caveolae are proposed to play mechanosensing roles, and caveola‐forming proteins are overexpressed in GBM. We asked whether caveolae mediate the GBM response to osmotic pressure. We evaluated in vitro the influence of spontaneous or experimental down‐regulation of caveola‐forming proteins (caveolin‐1, CAVIN1) on the proteolytic profile and invasiveness of GBM cells in response to osmotic pressure. In response to osmotic pressure, GBM cell lines expressing caveola‐forming proteins up‐regulated plasminogen activator (uPA) and/or matrix metalloproteinases (MMPs), some EMT markers and increased their in vitro invasion potential. Down‐regulation of caveola‐forming proteins impaired this response and prevented hyperosmolarity‐induced mRNA expression of the water channel aquaporin 1. CRISPR ablation of caveola‐forming proteins further lowered expression of matrix proteases and EMT markers in response to hydrostatic pressure, as a model of mechanical force. GBM respond to pressure by increasing matrix‐degrading enzyme production, mesenchymal phenotype and invasion. Caveola‐forming proteins mediate, at least in part, the pro‐invasive response of GBM to pressure. This may represent a novel target in GBM treatment.

Allosteric regulation of protein 14-3-3ζ scaffold by small-molecule editing modulates histone H3 post-translational modifications

Background: Histone post-translational modifications (PTMs) are involved in various biological processes such as transcriptional activation, chromosome packaging, and DNA repair. Previous studies mainly focused on PTMs by directly targeting histone-modifying enzymes such as HDACs and HATs.

Methods and Results: In this study, we discovered a previously unexplored regulation mechanism for histone PTMs by targeting transcription regulation factor 14-3-3ζ. Mechanistic studies revealed 14-3-3ζ dimerization as a key prerequisite, which could be dynamically induced via an allosteric effect. The selective inhibition of 14-3-3ζ dimer interaction with histone H3 modulated histone H3 PTMs by exposing specific modification sites including acetylation, trimethylation, and phosphorylation, and reprogrammed gene transcription profiles for autophagy-lysosome function and endoplasmic reticulum stress.

Conclusion: Our findings demonstrate the feasibility of editing histone PTM patterns by targeting transcription regulation factor 14-3-3ζ, and provide a distinctive PTM editing strategy which differs from current histone modification approaches.

Extracellular vesicles and their role in glioblastoma

Research on the role of extracellular vesicles (EVs) in disease pathogenesis has been rapidly growing over the last two decades. As EVs can mediate intercellular communication, they can ultimately facilitate both normal and pathological processes through the delivery of their bioactive cargo, which may include nucleic acids, proteins and lipids. EVs have emerged as important regulators of brain tumors, capable of transferring oncogenic proteins, receptors, and small RNAs that may support brain tumor progression, including in the most common type of brain cancer, glioma. Investigating the role of EVs in glioma is crucial, as the most malignant glioma, glioblastoma (GBM), is incurable with a dismal median survival of 12-15 months. EV research in GBM has primarily focused on circulating brain tumor-derived vesicles in biofluids, such as blood and cerebrospinal fluid (CSF), investigating their potential as diagnostic and prognostic biomarkers. Gaining a greater understanding of the role of EVs and their cargo in brain tumor progression may contribute to the discovery of novel diagnostics and therapeutics. In this review, we summarize the known and emerging functions of EVs in glioma biology and pathogenesis, as well as their emerging biomarker potential.

PTRF independently predicts progression and survival in multiracial upper tract urothelial carcinoma following radical nephroureterectomy

OBJECTIVES

Polymerase I and transcript release factor (PTRF) has been implicated in cancer biology but its role in upper tract urothelial carcinoma (UTUC) is unknown. From a pilot transcriptome, we identified PTRF was significantly upregulated in high stage UTUC. Bladder cancer transcriptome from The Cancer Genome Atlas (TCGA) supported our finding and high PTRF level also predicted poor survival. We, therefore, investigated the correlation of PTRF with patients' clinicopathologic characteristics and outcomes in a multiracial UTUC cohort.

MATERIALS AND METHODS

By immunohistochemical staining, PTRF expression was determined using H-score. PTRF expression of 575 UTUCs from 8 institutions, including 118 Asians and 457 Caucasians, was compared with various clinicopathologic parameters. Human urothelial cancer cell lines were used to evaluate the level of PTRF protein and mRNA expression, and PTRF transcript level was assessed in fresh samples from 12 cases of the cohort. The impact of PTRF expression on disease progression, cancer-specific death and overall mortality was also examined.

RESULTS

High PTRF expression was significantly associated with multifocality (P = 0.023), high pathologic tumor stage (P < 0.00001), nonurothelial differentiation (P = 0.035), lymphovascular invasion (P = 0.003) and lymph node metastasis (P = 0.031). PTRF mRNA expression was also markedly increased in advanced stage UTUC (P = 0.0003). High PTRF expressing patients had consistently worse outcomes than patients with low PTRF expression regardless of demographic variation (all P < 0.005). In multivariate analysis, high PTRF expression was an independent predictor for progression-free survival (hazard ratio [HR] 1.70, 95% confidence interval [CI] 1.07-2.69, P = 0.025), cancer-specific survival (HR 2.09, 95% CI 1.28-3.42, P = 0.003), and overall survival (HR 2.04, 95% CI 1.33-3.14, P = 0.001).

CONCLUSIONS

Results indicate that PTRF is a predictive biomarker for progression and survival and an independent prognosticator of UTUC. Elevated PTRF could probably propel clinically aggressive disease and serve as a potential therapeutic target for UTUC.

Identification of miRNA signatures in serum exosomes as a potential biomarker after radiotherapy treatment in glioma patients

Despite development in therapies, the high recurrence and low positivity of biomarkers for diagnosis still result in glioma with high mortality. In this study, we aimed to identify a potential miRNA signature to evaluate the effect of radiotherapy in glioma patients. MicroRNA (miRNA) sequencing was performed on miRNAs isolated from serum exosomes in a cohort of glioma patients before and after radiotherapy. A total of 18 up-regulated differentially expressed (DE) miRNAs and 16 down-regulated DE miRNAs were identified. Subsequently, the target genes of DE miRNAs were predicted based on multiple miRNA-target databases. Further, it was indicated that these targets were primarily involved in metabolic process, p53 signaling pathway and cancer pathways, suggesting that these miRNAs play a crucial role in glioma by regulating targets and affect the occurrence and development of the disease. In general, this study presented the variation of miRNAs in blood exosomes before and after radiotherapy. It can not only be helpful for the diagnosis of glioma, but also find new candidate biomarkers for monitoring the condition and evaluating the efficacy of radiotherapy in glioma. It provides a new idea for the diagnosis, treatment and prognosis evaluation of glioma.

Single-cell RNA-seq reveals RAD51AP1 as a potent mediator of EGFRvIII in human glioblastomas

Recent advances in single-cell RNA sequencing (scRNA-seq) have endowed researchers with the ability to detect and analyze the transcriptomes of individual cancer cells. In the present study, 16,128 tumor cells from EGFR wild-type and EGFRvIII mutant cells were profiled by scRNA-seq. Analyses of scRNA-seq data from both U87MG and U87MG-EGFRvIII libraries revealed inherent heterogeneity in gene expression and biological processes. The cells stably expressing EGFRvIII showed enhanced transcriptional activities and a relatively homogeneous pattern, which manifested as less diverse distributions, gene expression levels and functional annotations compared with those of cells expressing the nonmutated version. Moreover, the differentially expressed genes between the U87MG and U87MG-EGFRvIII groups were mainly enriched in DNA replication, DNA repair and angiogenesis. We compared scRNA-seq data with bulk RNA-seq and EGFRvIII xenograft RNA-seq data. RAD51AP1 was shown to be upregulated in all three databases. Further analysis of RAD51AP1 revealed that it is an independent prognostic factor of glioma. Knocking down RAD51AP1 significantly inhibited tumor volume in an intracranial EGFRvIII-positive GBM model and prolonged survival time. Collectively, our microfluidic-based scRNA-seq driven by a single genetic event revealed a previously unappreciated implication of EGFRvIII in the heterogeneity of GBM and identified RAD51AP1 as an oncogene in glioma.

Genome-Wide CRISPR-Cas9 Screening Identifies NF-κB/E2F6 Responsible for EGFRvIII-Associated Temozolomide Resistance in Glioblastoma

Amplification of epidermal growth factor receptor (EGFR) and active mutant EGFRvIII occurs frequently in glioblastoma (GBM) and contributes to chemo/radio-resistance in various cancers, especially in GBM. Elucidating the underlying molecular mechanism of temozolomide (TMZ) resistance in GBM could benefit cancer patients. A genome-wide screening under a clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 library is conducted to identify the genes that confer resistance to TMZ in EGFRvIII-expressing GBM cells. Deep sgRNA sequencing reveals 191 candidate genes that are responsible for TMZ resistance in EGFRvIII-expressing GBM cells. Notably, E2F6 is proven to drive a TMZ resistance, and E2F6 expression is controlled by the EGFRvIII/AKT/NF-κB pathway. Furthermore, E2F6 is shown as a promising therapeutic target for TMZ resistance in orthotopic GBM cell line xenografts and GBM patient-derived xenografts models. After integrating clinical data with paired primary-recurrent RNA sequencing data from 134 GBM patients who received TMZ treatment after surgery, it has been revealed that the E2F6 expression level is a predictive marker for TMZ response. Therefore, the inhibition of E2F6 is a promising strategy to conquer TMZ resistance in GBM.

Proteomic Advances in Glial Tumors through Mass Spectrometry Approaches

Being the fourth leading cause of cancer-related death, glial tumors are highly diverse tumor entities characterized by important heterogeneity regarding tumor malignancy and prognosis. However, despite the identification of important alterations in the genome of the glial tumors, there remains a gap in understanding the mechanisms involved in glioma malignancy. Previous research focused on decoding the genomic alterations in these tumors, but due to intricate cellular mechanisms, the genomic findings do not correlate with the functional proteins expressed at the cellular level. The development of mass spectrometry (MS) based proteomics allowed researchers to study proteins expressed at the cellular level or in serum that may provide new insights on the proteins involved in the proliferation, invasiveness, metastasis and resistance to therapy in glial tumors. The integration of data provided by genomic and proteomic approaches into clinical practice could allow for the identification of new predictive, diagnostic and prognostic biomarkers that will improve the clinical management of patients with glial tumors. This paper aims to provide an updated review of the recent proteomic findings, possible clinical applications, and future research perspectives in diffuse astrocytic and oligodendroglial tumors, pilocytic astrocytomas, and ependymomas.

Advances in exosome isolation methods and their applications in proteomic analysis of biological samples

Exosomes are membrane-bound vesicles secreted by cells, and contain various important biological molecules, such as lipids, proteins, messenger RNAs, microRNAs, and noncoding RNAs. Emerging evidence demonstrates that proteomic analysis of exosomes is of great significance in studying metabolic diseases, tumor metastasis, immune regulation, and so forth. However, exosome proteomic analysis has high requirements with regard to the purity of collected exosomes. Here recent advances in the methods for isolating exosomes and their applications in proteomic analysis are summarized. Graphical abstract.

The critical role of exosomes in tumor biology

Exosomes are a type of extracellular vesicles (diameter, 30-160 nm), which contain multiple proteins, nucleic acids, lipid molecules, and other substances. Most types of cells can secrete exosomes, although the biogenesis, composition, and function is specific to different cell types. Recently, many studies have demonstrated that exosomes play a critical role in tumor development. In this review, we briefly summarize the biogenesis, composition, and function of exosomes. We also discuss the recent advances in the critical role of exosomes in tumor biology with a special focus on their application in tumor diagnosis and treatment.

Correlation of the invasive potential of glioblastoma and expression of caveola-forming proteins caveolin-1 and CAVIN1

INTRODUCTION

Glioblastoma (GBM) is the most common primary brain cancer. The average survival time for the majority of patients is approximately 15 months after diagnosis. A major feature of GBM that contributes to its poor prognosis is its high invasiveness. Caveolae are plasma membrane subdomains that participate in numerous biological functions. Caveolin-1 and Caveolae Associated Protein 1 (CAVIN1), formerly termed Polymerase I and Transcript Release Factor, are both necessary for caveola formation. We hypothesized that high expression of caveola-forming proteins in GBM promotes invasiveness via modulation of the production of matrix-degrading enzymes.

METHODS

The mRNA expression of caveola-forming proteins and matrix proteases in GBM samples, and survival after stratifying patients according to caveolin-1 or CAVIN1 expression, were analyzed from TCGA and REMBRANDT databases. The proteolytic profile of cell lines expressing or devoid of caveola-forming proteins was investigated using zymography and real-time qPCR. Invasion through basement membrane-like protein was investigated in vitro.

RESULTS

Expression of both caveolin-1 and CAVIN1 was increased in GBM compared to normal samples and correlated with expression of urokinase plasminogen activator (uPA) and gelatinases. High expression of caveola-forming proteins was associated with shorter survival time. GBM cell lines capable of forming caveolae expressed more uPA and matrix metalloproteinase-2 (MMP-2) and/or -9 (MMP-9) and were more invasive than GBM cells devoid of caveola-forming proteins. Experimental manipulation of caveolin-1 or CAVIN1 expression in GBM cells recapitulated some, but not all of these features. Caveolae modulate GBM cell invasion in part via matrix protease expression.

The emerging clinical potential of circulating extracellular vesicles for non-invasive glioma diagnosis and disease monitoring

Diffuse gliomas (grades II-IV) are amongst the most frequent and devastating primary brain tumours of adults. Currently, patients are monitored by clinical examination and radiographic imaging, which can be challenging to interpret and insensitive to early signs of treatment failure and tumour relapse. While brain biopsy and histologic analysis can evaluate disease progression, serial biopsies are invasive and impractical given the cumulative surgical risk, and may not capture the complete molecular landscape of an evolving tumour. The availability of a minimally invasive 'liquid biopsy' that could assess tumour activity and molecular phenotype in situ has the potential to greatly enhance patient care. Circulating extracellular vesicles (EVs) hold significant promise as robust disease-specific biomarkers accessible in the blood of patients with glioblastoma and other diffuse gliomas. EVs are membrane-bound nanoparticles shed from most if not all cells of the body, and carry DNA, RNA, protein, and lipids that reflect the identity and molecular state of their cell-of-origin. EVs can cross the blood-brain barrier and their release is upregulated in neoplasia. In this review, we describe the current knowledge of EV biology, the role of EVs in glioma biology and the current experience and challenges in profiling glioma-EVs from the circulation.

The potential diagnostic and prognostic role of extracellular vesicles in glioma: current status and future perspectives

Lack of appropriate diagnostic/prognostic tools for glioblastoma (GB) is considered one of the major setbacks in the early diagnosis and treatment of this deadly brain tumor. The current gold standard for its diagnosis and staging still relies on invasive biopsy followed by histological examination as well as molecular profiling. Nevertheless, noninvasive approaches are being explored and one example is through the investigation of extracellular vesicles (EVs) in the biofluids of GB patients. EVs are known to carry molecular cargoes such as DNA, mRNA, miRNA, proteins and lipids in almost every type of body fluids. Thus, molecular signature of GB may be present in the EVs derived from these patients. This review focuses on the diagnostic/prognostic potential of EVs in GB, through presenting recent studies on (i) molecular components of EVs, (ii) links between EVs and GB tumor microenvironment, and (iii) clinical potential of EV biomarkers, together with the technical shortcomings researchers need to consider for future studies.

Correlation of alteration of HLA-F expression and clinical characterization in 593 brain glioma samples

Background

Human gliomas are highly fatal tumors with a significant feature of immune suppression. The association of the immune system in gliomas is gradually revealed, and immunotherapy is expected to improve the survival of glioma patients. In-depth understanding of the immune microenvironment of gliomas and their associated immunotherapy was increased exponentially in recent years. Gliomas provide clinical targets for immunotherapy during the search of key regulators of immune response. Our study focused on the human leukocyte antigen (HLA) system that is responsible for regulating the immune system, and discovered the relationship between HLA-F expression and clinical prognosis in gliomas.

Methods

A total of 593 patients with gliomas were included in our research. Of these, 325 patients were from the Chinese Glioma Genome Atlas (CGGA) and 268 were from the GSE 16011 set. Kaplan-Meier (KM) analysis was performed to explore the prognostic value of HLA-F. t test analysis was used to find the distribution difference in various groups. R language packages are used for other statistical computations and figure drawing.

Results

HLA-F was negatively correlated with overall survival (OS) in all grades of glioma and glioblastoma (GBM). Moreover, HLA-F was enriched in GBM and isocitrate dehydrogenase 1 wild-type (IDH1 wt) group and considered HLA-F as a mesenchymal subtype marker. Pearson correlation test showed that HLA-F was correlated with other HLA-I molecules.

Conclusion

HLA-F expression was positively correlated with malignant phenotype and negatively correlated with OS, indicating that HLA-F could predict the immune state of gliomas and might be a clinical target of glioma immunotherapy.

Proteomic Analysis of Extracellular Vesicles for Cancer Diagnostics

Extracellular vesicles (EVs) including exosomes and microvesicles are lipid bilayer-encapsulated nanoparticles released by cells, ranging from 40 nm to several microns in diameter. Biological cargoes including proteins, RNAs, and DNAs can be ferried by EVs to neighboring and distant cells via biofluids, serving as a means of cell-to-cell communication under normal and pathological conditions, especially cancers. On the other hand, EVs have been investigated as a novel "information capsule" for early disease detection and monitoring via liquid biopsy. This review summarizes current advancements in EV subtype characterization, cancer EV capture, proteomic analysis technologies, as well as possible EV-based multiomics for cancer diagnostics.

On the Choice of the Extracellular Vesicles for Therapeutic Purposes

Extracellular vesicles (EVs) are lipid membrane vesicles released by all human cells and are widely recognized to be involved in many cellular processes, both in physiological and pathological conditions. They are mediators of cell-cell communication, at both paracrine and systemic levels, and therefore they are active players in cell differentiation, tissue homeostasis, and organ remodeling. Due to their ability to serve as a cargo for proteins, lipids, and nucleic acids, which often reflects the cellular source, they should be considered the future of the natural nanodelivery of bio-compounds. To date, natural nanovesicles, such as exosomes, have been shown to represent a source of disease biomarkers and have high potential benefits in regenerative medicine. Indeed, they deliver both chemical and bio-molecules in a way that within exosomes drugs are more effective that in their exosome-free form. Thus, to date, we know that exosomes are shuttle disease biomarkers and probably the most effective way to deliver therapeutic molecules within target cells. However, we do not know exactly which exosomes may be used in therapy in avoiding side effects as well. In regenerative medicine, it will be ideal to use autologous exosomes, but it seems not ideal to use plasma-derived exosomes, as they may contain potentially dangerous molecules. Here, we want to present and discuss a contradictory relatively unmet issue that is the lack of a general agreement on the choice for the source of extracellular vesicles for therapeutic use.

Exosomes: Isolation, Analysis, and Applications in Cancer Detection and Therapy

Exosomes are cell-derived small extracellular vesicles that are naturally secreted by all types of cells and widely distributed in various biofluids. They carry a variety of key bioactive molecules (e.g., nucleic acids, proteins, growth factors, cytokines) from their parent cells and convey them to neighboring or even distant cells through circulation. In recent years, tumor-derived exosomes have attracted great interest from investigators because they actively participate in nearly all aspects of tumor development and facilitate both tumor growth and metastasis through exosome-mediated intercellular communication. The vesicular contents are increasingly considered potential biomarkers for tumor diagnoses and prognosis. With the progress made in isolation and analytical technologies, the functions of exosomes and their contents in tumor development are also becoming clearer. In this review article we describe the recent developments in exosome isolation techniques and analysis of exosomal contents. We also address their applications in cancer detection and therapy.

AHIF promotes glioblastoma progression and radioresistance via exosomes

Glioblastoma multiforme (GBM) has the highest mortality rate among patients with brain tumors, and radiotherapy forms an important part of its treatment. Thus, there is an urgent requirement to elucidate the mechanisms conferring GBM progression and radioresistance. In the present study, it was identified that antisense transcript of hypoxia‑inducible factor‑1α (AHIF) was significantly upregulated in GBM cancerous tissues, as well as in radioresistant GBM cells. The expression of AHIF was also upregulated in response to radiation. Knockdown of AHIF in GBM cells decreased viability and invasive capacities, and increased the proportion of apoptotic cells. By contrast, overexpression of AHIF in GBM cells increased viability and invasive capacities, and decreased the proportion of apoptotic cells. Furthermore, exosomes derived from AHIF‑knockdown GBM cells inhibited viability, invasion and radioresistance, whereas exosomes derived from AHIF‑overexpressing GBM cells promoted viability, invasion and radioresistance. Further biochemical analysis identified that AHIF regulates factors associated with migration and angiogenesis in exosomes. To the best of our knowledge, the present study is the first to establish that AHIF promotes glioblastoma progression and radioresistance via exosomes, which suggests that AHIF is a potential therapeutic target for GBM.

Integrated profiling identifies caveolae-associated protein 1 as a prognostic biomarker of malignancy in glioblastoma patients

AIMS

Glioblastoma (GBM) is a lethal disease of the central nervous system with high mortality, and novel therapeutic targets and strategies for GBM are urgently needed. Caveolae-associated protein 1 (CAVIN1) is an essential caveolar component-encoding gene and has been poorly studied in glioma. To this end, in this study, we evaluated CAVIN1 expression in glioma tissue as well as the correlation between CAVIN1 expression and prognosis in glioma patients using the data collected from clinical samples or from the Cancer Genome Atlas (TCGA), Chinese Glioma Genome Atlas (CGGA), Rembrandt, and Gene Expression Omnibus (GEO) data sets.

METHODS

Survival analysis was performed with the Kaplan-Meier curve and log-rank test. The predictive role of CAVIN1 in progressive malignancy in glioma was evaluated by using a receiver operator characteristic (ROC) curve. Gene ontology (GO), Gene set enrichment analysis (GSEA), and gene set variation analysis (GSVA) methods were used to interpret the functions of CAVIN1 in GBM.

RESULTS

CAVIN1 expression was elevated in GBM compared with that in low-grade glioma and nontumor brain samples and was correlated with unfavorable outcomes in glioma patients. Additionally, CAVIN1 could serve as an independent predictive factor for progressive malignancy in GBM. Furthermore, CAVIN1 was associated with disrupted angiogenesis and immune response in the tumor microenvironment of GBM.

CONCLUSIONS

We identified CAVIN1 as a prognostic biomarker and potential target for developing novel therapeutic strategies against GBM.

Exosomes in cancer: Small transporters with big functions

Exosomes are nanosized membrane-bound vesicles containing abundant proteins, DNA, mRNA, and non-coding RNAs. Exosomes are now considered as an additional mechanism for intercellular communication, allowing cells to exchange proteins, lipids and genetic material. Increasing studies have shown that exosomes play an important role in tumour initiation, growth, progression, metastasis, drug resistance and immune escape. In this article, we review recent advances in the biology of exosomes. We elaborate the specific mechanism by which exosomes affect the communication between tumours and the microenvironment. Finally, we report that exosomes may provide promising biomarkers for cancer diagnosis and represent new targets for cancer therapy.