Extracellular vesicles in the tumor microenvironment: old stories, but new tales

Research Progress on the Predicting Factors and Coping Strategies for Postoperative Recurrence of Esophageal Cancer

Esophageal cancer is one of the malignant tumors with poor prognosis in China. Currently, the treatment of esophageal cancer is still based on surgery, especially in early and mid-stage patients, to achieve the goal of radical cure. However, esophageal cancer is a kind of tumor with a high risk of recurrence and metastasis, and locoregional recurrence and distant metastasis are the leading causes of death after surgery. Although multimodal comprehensive treatment has advanced in recent years, the prediction, prevention and treatment of postoperative recurrence and metastasis of esophageal cancer are still unsatisfactory. How to reduce recurrence and metastasis in patients after surgery remains an urgent problem to be solved. Given the clinical demand for early detection of postoperative recurrence of esophageal cancer, clinical and basic research aiming to meet this demand has been a hot topic, and progress has been observed in recent years. Therefore, this article reviews the research progress on the factors that influence and predict postoperative recurrence of esophageal cancer, hoping to provide new research directions and treatment strategies for clinical practice.

Direct detection of circulating donor-derived extracellular vesicles in kidney transplant recipients

Extracellular vesicles (EVs) are tissue-specific particles containing valuable diagnostic information. However, single EV analysis in blood is challenging due to their physical properties, the molecular complexity of plasma, and a lack of robust data interpretation methods. We assess the applicability of our recently-developed calibrated Imaging Flow Cytometry (IFCM)-based methodology to detect/characterize circulating tissue-specific EV subsets in the clinical setting of kidney transplantation. Platelet-poor plasma was generated from 36 HLA-A3 mismatched donor (HLA-A3 +) and kidney transplant recipients (KTRs; HLA-A3-). Samples taken before transplantation, 3 days, 7 days, and 6 months after transplantation as well as before 'for-cause' kidney transplant biopsies were stained with anti-CD9 (plasma EV-marker) and anti-HLA-A3. Before transplantation, no significant differences in total CD9 + EV concentrations were detected between donor and KTR samples. Tissue-specific EVs were identified as CD9 + HLA-A3 + . Serial dilution experiments of HLA-A3 + in HLA-A3- PPP showed that single CD9 + HLA-A3 + EVs were detectable down to ~ 1% above the recipient 'self-signal'. After transplantation, CD9 + HLA-A3 + EVs were detected above pre-transplantation concentrations in individuals with stable allograft function, but not in individuals with allograft dysfunction. These results demonstrate the applicability of our calibrated IFCM-based methodology in the direct detection of tissue-specific EV subsets in clinical samples. We believe that this EV methodology is applicable in a variety of clinical contexts.

Extracellular Vesicles as Mediators of Nickel-Induced Cancer Progression

Emerging evidence suggests that extracellular vesicles (EVs), which represent a crucial mode of intercellular communication, play important roles in cancer progression by transferring oncogenic materials. Nickel (Ni) has been identified as a human group I carcinogen; however, the underlying mechanisms governing Ni-induced carcinogenesis are still being elucidated. Here, we present data demonstrating that Ni exposure generates EVs that contribute to Ni-mediated carcinogenesis and cancer progression. Human bronchial epithelial (BEAS-2B) cells and human embryonic kidney-293 (HEK293) cells were chronically exposed to Ni to generate Ni-treated cells (Ni-6W), Ni-transformed BEAS-2B cells (Ni-3) and Ni-transformed HEK293 cells (HNi-4). The signatures of EVs isolated from Ni-6W, Ni-3, HNi-4, BEAS-2B, and HEK293 were analyzed. Compared to their respective untreated cells, Ni-6W, Ni-3, and HNi-4 released more EVs. This change in EV release coincided with increased transcription of the EV biogenesis markers CD82, CD63, and flotillin-1 (FLOT). Additionally, EVs from Ni-transformed cells had enriched protein and RNA, a phenotype also observed in other studies characterizing EVs from cancer cells. Interestingly, both epithelial cells and human umbilical vein endothelial (HUVEC) cells showed a preference for taking up Ni-altered EVs compared to EVs released from the untreated cells. Moreover, these Ni-altered EVs induced inflammatory responses in both epithelial and endothelial cells and increased the expression of coagulation markers in endothelial cells. Prolonged treatment of Ni-alerted EVs for two weeks induced the epithelial-to-mesenchymal transition (EMT) in BEAS-2B cells. This study is the first to characterize the effect of Ni on EVs and suggests the potential role of EVs in Ni-induced cancer progression.

Message in the bottle: regulation of the tumor microenvironment via exosome-driven proteolysis

Exosomes comprise a subtype of extracellular vesicles involved in cell-to-cell communication, specifically by transporting biological molecules, such as proteins and nucleic acids, to either local or more distant recipient cells, thus triggering distinct biological behaviors. Included in the exosome cargo is frequently a wide range of proteolytic enzymes, such as the matrix metalloproteinases (MMPs), the disintegrin and metalloproteinases (ADAMs), and the ADAM with thrombospondin-like motifs (ADAMTSs), whose functions contribute to the development and progression of cancer. In recent years, extensive research on the potential use of exosomes in diagnostic and therapeutic applications for personalized medicine has emerged, but the targeting of the proteolytic cargo of exosomes has not been fully exploited in this direction. In this review, we aim to explore both the mechanistic and the translational importance of proteolytic enzymes carried by the tumor cell-derived exosomes, as well as their role in the acquisition and support of certain hallmarks of cancer.

Role of extracellular vesicles in cancer-specific interactions between tumour cells and the vasculature

Cancer progression impacts and exploits the vascular system in several highly consequential ways. Among different types of vascular cells, blood cells and mediators that are engaged in these processes, endothelial cells are at the centre of the underlying circuitry, as crucial constituents of angiogenesis, angiocrine stimulation, non-angiogenic vascular growth, interactions with the coagulation system and other responses. Tumour-vascular interactions involve soluble factors, extracellular matrix molecules, cell-cell contacts, as well as extracellular vesicles (EVs) carrying assemblies of molecular effectors. Oncogenic mutations and transforming changes in the cancer cell genome, epigenome and signalling circuitry exert important and often cancer-specific influences upon pathways of tumour-vascular interactions, including the biogenesis, content, and biological activity of EVs and responses of cancer cells to them. Notably, EVs may carry and transfer bioactive, oncogenic macromolecules (oncoproteins, RNA, DNA) between tumour and vascular cells and thereby elicit unique functional changes and forms of vascular growth and remodeling. Cancer EVs influence the state of the vasculature both locally and systemically, as exemplified by cancer-associated thrombosis. EV-mediated communication pathways represent attractive targets for therapies aiming at modulation of the tumour-vascular interface (beyond angiogenesis) and could also be exploited for diagnostic purposes in cancer.

Warburg effect in colorectal cancer: the emerging roles in tumor microenvironment and therapeutic implications

Colorectal cancer (CRC) is the third most common cancer and the second leading cause of cancer-related death worldwide. Countless CRC patients undergo disease progression. As a hallmark of cancer, Warburg effect promotes cancer metastasis and remodels the tumor microenvironment, including promoting angiogenesis, immune suppression, cancer-associated fibroblasts formation and drug resistance. Targeting Warburg metabolism would be a promising method for the treatment of CRC. In this review, we summarize information about the roles of Warburg effect in tumor microenvironment to elucidate the mechanisms governing Warburg effect in CRC and to identify novel targets for therapy.

miR-214-Enriched Extracellular Vesicles Released by Acid-Adapted Melanoma Cells Promote Inflammatory Macrophage-Dependent Tumor Trans-Endothelial Migration

Simple Summary

Cutaneous melanoma is the most aggressive form of skin cancer with high-metastatic ability. Despite the recent advancements in melanoma treatments, the prognosis of metastatic patients remains very poor. A better understanding of the molecular mechanisms leading to melanoma dissemination is urgently needed in order to develop novel therapeutical strategies to ameliorate patients’ outcomes. Extracellular vesicles (EV) released by tumor cells are key players in metastasis development: by conveying bioactive molecules with oncogenic activity, they can modulate the surrounding—and even the distant—microenvironment and reprogram recipient cells to facilitate the metastatic cascade. Here, we show that melanoma cells release a higher amount of miR-214-enriched EV when adapted to extracellular acidosis, which promote a macrophage activation state, capable of facilitating the trans-endothelial migration of melanoma cells. Thus, we disclose a new molecular mechanism to prevent melanoma intravasation based on miR-214 targeting.

Abstract

The understanding of the molecular mechanisms leading to melanoma dissemination is urgently needed in view of the identification of new targets and the development of innovative strategies to improve patients’ outcomes. Within the complexity of tumor intercellular communications leading to metastatic dissemination, extracellular vesicles (EV) released by tumor cells are central players. Indeed, the ability to travel through the circulatory system conveying oncogenic bioactive molecules even at distant sites makes EV capable of modulating recipient cells to facilitate metastatic dissemination. The dynamic remodeling of the tumor microenvironment might influence, along with a number of other events, tumoral EV release. We observed that, in melanoma, extracellular acidosis increases the release of EV enriched in miR-214, an onco-miRNA involved in melanoma metastasis. Then, miR-214-enriched EV were found to induce a state of macrophage activation, leading to an overproduction of proinflammatory cytokines and nitric oxide. Such an inflammatory microenvironment was able to alter the endothelial cell permeability, thereby facilitating the trans-endothelial migration of melanoma cells, a crucial step in the metastatic cascade. The use of synthetic miR-214 inhibitors and miR-214 overexpression allowed us to demonstrate the key role of miR-214 in the EV-dependent induction of macrophage activation. Overall, our in vitro study reveals that the release of tumor miR-214-enriched EV, potentiated by adapting tumor cells to extracellular acidosis, drives a macrophage-dependent trans-endothelial migration of melanoma cells. This finding points to miR-214 as a potential new therapeutic target to prevent melanoma intravasation.

High Blood Concentration of Leukocyte-Derived Extracellular Vesicles Is Predictive of Favorable Clinical Outcomes in Patients with Pancreatic Cancer: Results from a Multicenter Prospective Study

Pancreatic cancer (PC) is one of the leading causes of cancer-related death worldwide. Identification of novel tumor biomarkers is highly advocated in PC to optimize personalized treatment algorithms. Blood-circulating extracellular vesicles hold promise for liquid biopsy application in cancer. We used an optimized flow cytometry protocol to study leukocyte-derived EVs (CD45+) and PD-L1+ EVs in blood from 56 pancreatic cancer patients and 48 healthy controls (HCs). Our results show that PC patients presented higher blood levels of total EVs (p = 0.0003), leukocyte-derived EVs (LEVs) (p = 0.001) and PD-L1+ EVs (p = 0.01), as compared with HCs. Interestingly, a blood concentration of LEVs at baseline was independently associated with improved overall survival in patients with borderline resectable or primary unresectable PC (HR = 0.17; 95% CI 0.04-0.79; p = 0.02). Additionally, increased blood-based LEVs were independently correlated with prolonged progression-free survival (HR = 0.10; 95% CI 0.01-0.82; p = 0.03) and significantly associated with higher disease control rate (p = 0.02) in patients with advanced PC receiving standard chemotherapy. Notably, a strong correlation between a decrease in blood LEVs concentration during chemotherapy and disease control was observed (p = 0.005). These intriguing findings point to the potential of LEVs as novel blood-based EV biomarkers for improved personalized medicine in patients affected by PC.

Delineating the role of extracellular vesicles in cancer metastasis: A comprehensive review

Extracellular vesicles (EVs) are subcellular messengers that aid in the formation and spread of cancer by enabling tumor-stroma communication. EVs develop from the very porous structure of late endosomes and hold information on both the intrinsic “status” of the cell and the extracellular signals absorbed by the cells from their surroundings. These EVs contain physiologically useful components, including as nucleic acids, lipids, and proteins, which have been found to activate important signaling pathways in tumor and tumor microenvironment (TME) cells, aggravating tumor growth. We highlight critical cell biology mechanisms that link EVS formation to cargo sorting in cancer cells in this review.Sorting out the signals that control EVs creation, cargo, and delivery will aid our understanding of carcinogenesis. Furthermore, we reviewed how cancer development and spreading behaviors are affected by coordinated communication between malignant and non-malignant cells. Herein, we studied the reciprocal exchanges via EVs in various cancer types. Further research into the pathophysiological functions of various EVs in tumor growth is likely to lead to the discovery of new biomarkers in liquid biopsy and the development of tumor-specific therapies.

Recent advances in conventional and unconventional vesicular secretion pathways in the tumor microenvironment

All cells in the changing tumor microenvironment (TME) need a class of checkpoints to regulate the balance among exocytosis, endocytosis, recycling and degradation. The vesicular trafficking and secretion pathways regulated by the small Rab GTPases and their effectors convey cell growth and migration signals and function as meditators of intercellular communication and molecular transfer. Recent advances suggest that Rab proteins govern conventional and unconventional vesicular secretion pathways by trafficking widely diverse cargoes and substrates in remodeling TME. The mechanisms underlying the regulation of conventional and unconventional vesicular secretion pathways, their action modes and impacts on the cancer and stromal cells have been the focus of much attention for the past two decades. In this review, we discuss the current understanding of vesicular secretion pathways in TME. We begin with an overview of the structure, regulation, substrate recognition and subcellular localization of vesicular secretion pathways. We then systematically discuss how the three fundamental vesicular secretion processes respond to extracellular cues in TME. These processes are the conventional protein secretion via the endoplasmic reticulum-Golgi apparatus route and two types of unconventional protein secretion via extracellular vesicles and secretory autophagy. The latest advances and future directions in vesicular secretion-involved interplays between tumor cells, stromal cell and host immunity are also described.

Adipocyte-Derived Extracellular Vesicles Promote Prostate Cancer Cell Aggressiveness by Enabling Multiple Phenotypic and Metabolic Changes

Background: In recent decades, obesity has widely emerged as an important risk factor for prostate cancer (PCa). Adipose tissue and PCa cells have been shown to orchestrate a complex interaction network to support tumor growth and evolution; nonetheless, the study of this communication has only been focused on soluble factors, although increasing evidence highlights the key role of extracellular vesicles (EVs) in the modulation of tumor progression. Methods and Results: In the present study, we found that EVs derived from 3T3-L1 adipocytes could affect PC3 and DU145 PCa cell traits, inducing increased proliferation, migration and invasion. Furthermore, conditioning of both PCa cell lines with adipocyte-released EVs resulted in lower sensitivity to docetaxel, with reduced phosphatidylserine externalization and decreased caspase 3 and PARP cleavage. In particular, these alterations were paralleled by an Akt/HIF-1α axis-related Warburg effect, characterized by enhanced glucose consumption, lactate release and ATP production. Conclusions: Collectively, these findings demonstrate that EV-mediated crosstalk exists between adipocytes and PCa, driving tumor aggressiveness.

CD147 Promotes Tumorigenesis via Exosome-Mediated Signaling in Rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is an aggressive childhood soft-tissue tumor, with propensity for local invasion and distant metastasis. Exosomes are secreted vesicles that mediate paracrine signaling by delivering functional proteins and miRNA to recipient cells. The transmembrane protein CD147, also known as Basigin or EMMPRIN, is enriched in various tumor cells, as well as in tumor-derived exosomes, and has been correlated with poor prognosis in several types of cancer, but has not been previously investigated in RMS. We investigated the effects of CD147 on RMS cell biology and paracrine signaling, specifically its contribution to invasion and metastatic phenotype. CD147 downregulation diminishes RMS cell invasion and inhibits anchorage-independent growth in vitro. While treatment of normal fibroblasts with RMS-derived exosomes results in a significant increase in proliferation, migration, and invasion, these effects are reversed when using exosomes from CD147-downregulated RMS cells. In human RMS tissue, CD147 was expressed exclusively in metastatic tumors. Altogether, our results demonstrate that CD147 contributes to RMS tumor cell aggressiveness, and is involved in modulating the microenvironment through RMS-secreted exosomes. Targeted inhibition of CD147 reduces its expression levels within the isolated exosomes and reduces the capacity of these exosomes to enhance cellular invasive properties.

Proteomic Profile of Procoagulant Extracellular Vesicles Reflects Complement System Activation and Platelet Hyperreactivity of Patients with Severe COVID-19

Background

Extracellular vesicles (EVs) are a valuable source of biomarkers and display the pathophysiological status of various diseases. In COVID-19, EVs have been explored in several studies for their ability to reflect molecular changes caused by SARS-CoV-2. Here we provide insights into the roles of EVs in pathological processes associated with the progression and severity of COVID-19.

Methods

In this study, we used a label-free shotgun proteomic approach to identify and quantify alterations in EV protein abundance in severe COVID-19 patients. We isolated plasma extracellular vesicles from healthy donors and patients with severe COVID-19 by size exclusion chromatography (SEC). Then, flow cytometry was performed to assess the origin of EVs and to investigate the presence of circulating procoagulant EVs in COVID-19 patients. A total protein extraction was performed, and samples were analyzed by nLC-MS/MS in a Q-Exactive HF-X. Finally, computational analysis was applied to signify biological processes related to disease pathogenesis.

Results

We report significant changes in the proteome of EVs from patients with severe COVID-19. Flow cytometry experiments indicated an increase in total circulating EVs and with tissue factor (TF) dependent procoagulant activity. Differentially expressed proteins in the disease groups were associated with complement and coagulation cascades, platelet degranulation, and acute inflammatory response.

Conclusions

The proteomic data reinforce the changes in the proteome of extracellular vesicles from patients infected with SARS-CoV-2 and suggest a role for EVs in severe COVID-19.

Pathogenic Extracellular Vesicle (EV) Signaling in Amyotrophic Lateral Sclerosis (ALS)

Extracellular vesicles (EVs), once considered a pathway for cells to remove waste, have now emerged as an important mechanism for intercellular communication. EVs are particularly appealing in understanding the central nervous system (CNS) communication, given that there are very diverse cell types in the CNS and constant communications among various cells to respond to the frequently changing environment. While they are heterogeneous and new vesicles are continuously to be discovered, EVs are primarily classified as plasma membrane-derived microvesicles (MVs) and endosome-derived exosomes. Secretion of EVs has been shown from all CNS cell types in vitro and intercellular EV signaling has been implicated in neural development, axon integrity, neuron to glia communication, and propagation of protein aggregates formed by disease pathogenic proteins. However, significant hurdles remain to be tackled in understanding their physiological and pathological roles as well as how they can be developed as biomarkers or new therapeutics. Here we provide our summary on the known cell biology of EVs and discuss opportunities and challenges in understanding EV biology in the CNS and particularly their involvement in ALS pathogenesis.

An imaging flow cytometry-based methodology for the analysis of single extracellular vesicles in unprocessed human plasma

Extracellular vesicles (EVs) are tissue-specific particles released by cells containing valuable diagnostic information in the form of various biomolecules. To rule out selection bias or introduction of artefacts caused by EV isolation techniques, we present a clinically feasible, imaging flow cytometry (IFCM)-based methodology to phenotype and determine the concentration of EVs with a diameter ≤400 nm in human platelet-poor plasma (PPP) without prior isolation of EVs. Instrument calibration (both size and fluorescence) were performed with commercial polystyrene beads. Detergent treatment of EVs was performed to discriminate true vesicular events from artefacts. Using a combination of markers (CFSE & Tetraspanins, or CD9 & CD31) we found that >90% of double-positive fluorescent events represented single EVs. Through this work, we provide a framework that will allow the application of IFCM for EV analysis in peripheral blood plasma in a plethora of experimental and potentially diagnostic settings. Additionally, this direct approach for EV analysis will enable researchers to explore corners of EVs as cellular messengers in healthy and pathological conditions.

Prostate-Specific Membrane Antigen (PSMA)-Positive Extracellular Vesicles in Urine-A Potential Liquid Biopsy Strategy for Prostate Cancer Diagnosis?

All cells release extracellular vesicles (EVs) to communicate with adjacent and distant cells. Consequently, circulating EVs are found in all bodily fluids, providing information applicable for liquid biopsy in early cancer diagnosis. Studies observed an overexpression of the membrane-bound prostate-specific membrane antigen (PSMA) on prostate cancer cells. To investigate whether EVs derived from communicating prostate cells allow for reliable conclusions on prostate cancer development, we isolated PSMA-positive, as well as CD9-positive, EVs from cell-free urine with the use of magnetic beads. These populations of EVs were subsequently compared to CD9-positive EVs isolated from female urine in Western blotting, indicating the successful isolation of prostate-derived and ubiquitous EVs, respectively. Furthermore, we developed a device with an adapted protocol that enables an automated immunomagnetic enrichment of EVs of large sample volumes (up to 10 mL), while simultaneously reducing the overall bead loss and hands-on time. With an in-house spotted antibody microarray, we characterized PSMA as well as other EV surface markers of a prostate cohort of 44 urine samples in a more simplified way. In conclusion, the automated and specific enrichment of EVs from urine has a high potential for future diagnostic applications.

MALDI-TOF/MS Analysis of Extracellular Vesicles Released by Cancer Cells

The direct shedding of extracellular vesicles (EVs) from the plasma membrane is a recognized fundamental method for the intercellular transfer of properties in both physiological and pathological conditions. EVs are classified according to origin, biogenesis, size, content, surface markers, and/or functional properties, and contain various bioactive molecules depending on the physiological state and the type of the cells of origin including lipids, nucleic acids, and proteins. The presence of tumor-derived EVs in body fluids such as blood, ascites, urine, and saliva, together with the important role played in the tumor microenvironment where they intervene at different levels from oncogenesis to metastasis, make EVs a priority target for cancer studies. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) can play a leading role in the analysis and characterization of EVs and their load due to its intrinsic advantages such as high throughput, low sample consumption, speed, the cost-effectiveness of the analysis, and the ease of use. This work reviews the main MALDI-TOF applications for the analysis and characterization of extracellular vesicles in the tumor field.

Gastric Cancer-Derived Extracellular Vesicles (EVs) Promote Angiogenesis via Angiopoietin-2

Simple Summary

Angiogenesis is the formation of new blood vessels, which is essential for gastric cancer growth and metastasis. Angiopoietin-2 is a key driver of tumor angiogenesis and has recently emerged as a promising target for antiangiogenic therapy. Extracellular vesicles play an important role in tumor progression including angiogenesis. We explored the crosstalk between gastric cancer and endothelial cells mediated by vesicles, with a specific focus on angiopoietin-2. We show that primary gastric cancer and omental metastasis tissues express angiopoietin-2. We isolated gastric cancer vesicles and demonstrated that they induce the proliferation, migration, invasion, and tube formation of endothelial cells. Characterization of the angiogenic profile of these vesicles revealed high levels of proangiogenic proteins including angiopoietin-2. Using angiopoietin-2 knockdown, we demonstrate that angiopoietin-2 mediates the proangiogenic effects of the gastric cancer vesicles. Our findings suggest a new mechanism via which gastric cancer cells induce angiogenesis. Such a mechanism may be used as a target for cancer therapy.

Abstract

Angiogenesis is an important control point of gastric cancer (GC) progression and metastasis. Angiopoietin-2 (ANG2) is a key driver of tumor angiogenesis and metastasis, and it has been identified in primary GC tissues. Extracellular vesicles (EVs) play an important role in mediating intercellular communication through the transfer of proteins between cells. However, the expression of ANG2 in GC-EVs has never been reported. Here, we characterized the EV-mediated crosstalk between GC and endothelial cells (ECs), with particular focus on the role of ANG2. We first demonstrate that ANG2 is expressed in GC primary and metastatic tissues. We then isolated EVs from two different GC cell lines and showed that these EVs enhance EC proliferation, migration, invasion, and tube formation in vitro and in vivo. Using an angiogenesis protein array, we showed that GC-EVs contain high levels of proangiogenic proteins, including ANG2. Lastly, using Lenti viral ANG2-shRNA, we demonstrated that the proangiogenic effects of the GC-EVs were mediated by ANG2 through the activation of the PI3K/Akt signal transduction pathway. Our data suggest a new mechanism via which GC cells induce angiogenesis. This knowledge may be utilized to develop new therapies in gastric cancer.

The Dual Role of Mesenchymal Stromal Cells and Their Extracellular Vesicles in Carcinogenesis

Simple Summary

Extracellular vesicles (EVs) are membrane structures that play the role of intermediaries between tumor cells and the tumor microenvironment (TME) because they have the ability to transport lipids, transcription factors, mRNA, and proteins. Mesenchymal stem cells (MSCs) are a major component of the TME and may have different effects on tumor progression using EVs. This review includes information about various studies which have reported that EVs from MSCs can have either antitumor or pro-tumor effects, depending on both the tumor type and developmental stage. It provides an overview of the published data on EV MSCs and their effect on tumor cells. In addition, the use of EV MSCs for the development of new methods for treating oncological diseases is described.

Abstract

Mesenchymal stem cells (MSCs) are a major component of the tumor microenvironment (TME) and play an important role in tumor progression. MSCs remodel the extracellular matrix, participate in the epithelial–mesenchymal transition, promote the spread of metastases, and inhibit antitumor immune responses in the TME; however, there are also data pertaining to the antitumor effects of MSCs. MSCs activate the cell death mechanism by modulating the expression of proteins involved in the regulation of the cell cycle, angiogenesis receptors, and proapoptotic proteins. One of the main ways in which MSCs and TME interact is through the production of extracellular vesicles (EVs) by cells. Currently, data on the effects of both MSCs and their EVs on tumor cells are rather contradictory. Various studies have reported that EVs from MSCs can have either antitumor or pro-tumor effects, depending on both the tumor type and developmental stage. In this review, we discuss published data on EV MSCs and their effect on tumor cells. The molecular composition of vesicles obtained from MSCs is also presented in the review. In addition, the use of EV MSCs for the development of new methods for treating oncological diseases is described.

Cellular Crosstalk in the Vascular Wall Microenvironment: The Role of Exosomes in Vascular Calcification

Vascular calcification is prevalent in aging, diabetes, chronic kidney disease, cardiovascular disease, and certain genetic disorders. However, the pathogenesis of vascular calcification is not well-understood. It has been progressively recognized that vascular calcification depends on the bidirectional interactions between vascular cells and their microenvironment. Exosomes are an essential bridge to mediate crosstalk between cells and organisms, and thus they have attracted increased research attention in recent years. Accumulating evidence has indicated that exosomes play an important role in cardiovascular disease, especially in vascular calcification. In this review, we introduce vascular biology and focus on the crosstalk between the different vessel layers and how their interplay controls the process of vascular calcification.

Emerging roles of exosome-derived biomarkers in cancer theranostics: messages from novel protein targets

Effective biomarkers that guide therapeutics with limited adverse effects, have emerged as attractive research topics in cancer diagnosis and treatment. Cancer-derived exosomes, a type of extracellular vesicles representing molecular signatures of cells of origin, could serve as stable reservoirs for potential biomarkers (i.e., proteins, nucleic acids) in non-invasive cancer diagnosis and prognosis. In this review, the physiological and pathological roles of exosomes and their protein components in facilitating tumorigenesis are highlighted. Exosomes carrying proteins can participate in tumor development and progression through multiple signaling pathways, including EMT, invasion and metastasis. Meanwhile, the practical applications of exosomal proteins in detecting and monitoring several solid-tumor cancers (including lung, breast, pancreatic, colorectal and prostate cancers) were also summarized. More clinically relevant, exosomal proteins play pivotal roles in transmitting oncogenic potential or resistance to therapies in recipient cells, which might further support therapeutic strategy determinations.

Liver cancer cells with nuclear MET overexpression release translation regulatory protein-enriched extracellular vesicles exhibit metastasis promoting activity

MET receptor tyrosine kinase is a cell surface receptor that plays important role in embryonic development and tissue regeneration. Aberrant MET activation has been widely reported in different human cancers, making MET an attractive therapeutic target. The presence of truncated MET within the nucleus (nMET) with potential novel functions poses a great challenge to the current therapeutic strategies against MET surface receptor. Previous work has demonstrated the promoting effect of nMET in aggressive properties of hepatocellular carcinoma (HCC) cells by activating TAK1/NF-κB signalling pathway. Herein, we report the role of nMET in modulating tumour microenvironment and tumour metastasis mediated by extracellular vesicles (EVs). EVs released by nMET overexpressing cells enhanced cell motility and provoked metastasis. Proteomic profiling revealed the enrichment of translational regulatory proteins in EVs derived from nMET overexpressing cells. These proteins include eukaryotic initiation factor (EIF), ribosomal protein small subunit (RPS) and ribosomal protein larger subunit (RPL) gene families. Knockdown of EIF3I, RPS3A and RPL10 diminished the promoting effect of EVs in cell migration invasiveness and metastasis. In conclusion, the findings reveal an unrecognized capacity of nMET to augment HCC through the release of EVs with oncogenic effect. Targeting these translation-related proteins may serve as an alternative treatment for patients with nMET overexpression.

Extracellular Vesicles and the Inflammasome: An Intricate Network Sustaining Chemoresistance

Extracellular vesicles (EVs) are membrane enclosed spherical particles devoted to intercellular communication. Cancer-derived EVs (Ca-EVs) are deeply involved in tumor microenvironment remodeling, modifying the inflammatory phenotype of cancerous and non-cancerous residing cells. Inflammation plays a pivotal role in initiation, development, and progression of many types of malignancies. The key feature of cancer-related inflammation is the production of cytokines that incessantly modify of the surrounding environment. Interleukin-1β (IL-1β) is one of the most powerful cytokines, influencing all the initiation-to-progression stages of many types of cancers and represents an emerging critical contributor to chemoresistance. IL-1β production strictly depends on the activation of inflammasome, a cytoplasmic molecular platform sensing exogenous and endogenous danger signals. It has been recently shown that Ca-EVs can activate the inflammasome cascade and IL-1β production in tumor microenvironment-residing cells. Since inflammasome dysregulation has been established as crucial regulator in inflammation-associated tumorigenesis and chemoresistance, it is conceivable that the use of inflammasome-inhibiting drugs may be employed as adjuvant chemotherapy to counteract chemoresistance. This review focuses on the role of cancer-derived EVs in tuning tumor microenvironment unveiling the intricate network between inflammasome and chemoresistance.

Tumor-derived extracellular vesicles: Potential tool for cancer diagnosis, prognosis, and therapy

Various types of cancer pose a notable threat to human health globally. To date, many researchers have undertaken the search for anticancer therapies. However, many anticancer therapeutic approaches accompany many undesirable hazards. In this respect, extracellular vesicles as a whole gained excessive attention from the research community owing to their remarkable potential for delivery of anticancer agents since they are involved in distal intercellular communication via biological cargoes. With the discovery of the fact that tumor cells discharge huge quantities of EVs, new insights have been developed in cancer diagnosis and treatment. Tumor-derived extracellular vesicles (TD-EVs) can be distinguished from the normal cell-derived EVs due to the presence of specific labels on their surface. TD-EVs carry specific oncogenic proteins and the nucleic acids on their surface membrane that participate in tumor progression. Moreover, the proportion of these nucleic acids and the protein greatly varies among malignant and healthy cell-derived EVs. The diagnostic potential of TD-EVs can be implied for the more precise and early-stage detection of cancer that was impossible in the past. This review examines the recent progress in prognostic, diagnostic, and therapeutic potential of the EVs derived from the tumor cells.

Tailoring ZnO nanowire crystallinity and morphology for label-free capturing of extracellular vesicles

Zinc oxide (ZnO) nanowires have shown their potential in isolation of cancer-related biomolecules such as extracellular vesicles (EVs), RNAs, and DNAs for early diagnosis and therapeutic development of diseases. Since the function of inorganic nanowires changes depending on their morphology, previous studies have established strategies to control the morphology and have demonstrated attainment of improved properties for gas and organic compound detection, and for dye-sensitized solar cells and photoelectric conversion performance. Nevertheless, crystallinity and morphology of ZnO nanowires for capturing EVs, an important biomarker of cancer, have not yet been discussed. Here, we fabricated ZnO nanowires with different crystallinities and morphologies using an ammonia-assisted hydrothermal method, and we comprehensively analyzed the crystalline nature and oriented growth of the synthesized nanowires by X-ray diffraction and selected area electron diffraction using high resolution transmission electron microscopy. In evaluating the performance of label-free EV capture in a microfluidic device platform, we found both the crystallinity and morphology of ZnO nanowires affected EV capture efficiency. In particular, the zinc blende phase was identified as important for crystallinity, while increasing the nanowire density in the array was important for morphology to improve EV capture performance. These results highlighted that the key physicochemical properties of the ZnO nanowires were related to the EV capture performance.

Extracellular Vesicle-Mediated IL-1 Signaling in Response to Doxorubicin Activates PD-L1 Expression in Osteosarcoma Models

The expression of programmed cell death ligand 1 (PD-L1) in tumors is associated with tumor cell escape from T-cell cytotoxicity, and is considered a crucial effector in chemoresistance and tumor relapse. Although PD-L1 induction has been observed in patients after chemotherapy treatment, the mechanism by which the drug activates PD-L1 expression remains elusive. Here, we identified the extracellular vesicles (EVs) as a molecular mediator that determines the effect of doxorubicin on PD-L1 expression in osteosarcoma models. Mechanistically, doxorubicin dependently stimulates the release of extracellular vesicles, which mediate autocrine/paracrine signals in osteosarcoma cells. The recipient cells were stimulated by these EVs and acquired the ability to promote the expression of inflammatory cytokines interleukin (IL)-1β and IL-6. In response to doxorubicin, IL-1β, but not IL-6, allowed- osteosarcoma cells to promote the expression of PD-L1, and the elimination of IL-1β/IL-1 receptor signaling with IL-1 receptor antagonist reduced PD-L1 expression. Together, these findings provided insights into the role of EV release in response to chemotherapy that mediates PD-L1 expression via the IL-1 signaling pathway, and suggested that the combination of a drug targeting IL-1 or PD-L1 with chemotherapy could be an effective treatment option for osteosarcoma patients.

Blood Circulating CD133+ Extracellular Vesicles Predict Clinical Outcomes in Patients with Metastatic Colorectal Cancer

Simple Summary

In this study, we explored the prognostic and predictive value of blood circulating EVs expressing selected surface proteins in patients with metastatic colorectal cancer (mCRC). A recently patented flow cytometry protocol was used for the identification and subtyping of blood circulating EVs in a cohort of patients with stage IV colorectal cancer (n = 54) and in a cohort of healthy controls (n = 48). We observed an increased blood concentration of tumor-induced blood circulating EVs in the mCRC cohort as compared to healthy controls. Additionally, we show an intriguing link between circulating CD133+ EVs and poor clinical outcomes in patients with mCRC. This study provides novel insights about the potential impact of EVs as a relevant source of candidate biomarkers in mCRC.

Abstract

Colorectal cancer (CRC) is one of the most incident and lethal malignancies worldwide. Recent treatment advances prolonged survival in patients with metastatic colorectal cancer (mCRC). However, there are still few biomarkers to guide clinical management and treatment selection in mCRC. In this study, we applied an optimized flow cytometry protocol for EV identification, enumeration, and subtyping in blood samples of 54 patients with mCRC and 48 age and sex-matched healthy controls (HCs). The overall survival (OS) and overall response rate (ORR) were evaluated in mCRC patients enrolled and treated with a first line fluoropyrimidine-based regimen. Our findings show that patients with mCRC presented considerably higher blood concentrations of total EVs, as well as CD133+ and EPCAM+ EVs compared to HCs. Overall survival analysis revealed that increased blood concentrations of total EVs and CD133+ EVs before treatment were significantly associated with shorter OS in mCRC patients (p = 0.001; and p = 0.0001, respectively). In addition, we observed a correlation between high blood levels of CD133+ EVs at baseline and reduced ORR to first-line systemic therapy (p = 0.045). These findings may open exciting perspectives into the application of novel blood-based EV biomarkers for improved risk stratification and optimized treatment strategies in mCRC.

Glioblastoma Microenvironment and Cellular Interactions

Simple Summary

This paper summarizes the crosstalk between tumor/non-tumor cells and other elements of the glioblastoma (GB) microenvironment. In tumor pathology, glial cells result in the highest number of cancers, and GB is considered the most lethal tumor of the central nervous system (CNS). The tumor microenvironment (TME) is a complex peritumoral hallo composed of tumor cells and several non-tumor cells (e.g., nervous cells, stem cells, fibroblasts, vascular and immune cells), which might be a key factor for the ineffective treatment since the microenvironment modulates the biologic status of the tumor with the increase in its evasion capacity. A deeper understanding of cell–cell interactions in the TME and with the tumor cells could be the basis for a more efficient therapy.

Abstract

The central nervous system (CNS) represents a complex network of different cells, such as neurons, glial cells, and blood vessels. In tumor pathology, glial cells result in the highest number of cancers, and glioblastoma (GB) is considered the most lethal tumor in this region. The development of GB leads to the infiltration of healthy tissue through the interaction between all the elements of the brain network. This results in a GB microenvironment, a complex peritumoral hallo composed of tumor cells and several non-tumor cells (e.g., nervous cells, stem cells, fibroblasts, vascular and immune cells), which might be the principal factor for the ineffective treatment due to the fact that the microenvironment modulates the biologic status of the tumor with the increase in its evasion capacity. Crosstalk between glioma cells and the brain microenvironment finally inhibits the beneficial action of molecular pathways, favoring the development and invasion of the tumor and its increasing resistance to treatment. A deeper understanding of cell–cell interactions in the tumor microenvironment (TME) and with the tumor cells could be the basis for a more efficient therapy.

The Hippo pathway in cancer: YAP/TAZ and TEAD as therapeutic targets in cancer

Tumorigenesis is a highly complex process, involving many interrelated and cross-acting signalling pathways. One such pathway that has garnered much attention in the field of cancer research over the last decade is the Hippo signalling pathway. Consisting of two antagonistic modules, the pathway plays an integral role in both tumour suppressive and oncogenic processes, generally via regulation of a diverse set of genes involved in a range of biological functions. This review discusses the history of the pathway within the context of cancer and explores some of the most recent discoveries as to how this critical transducer of cellular signalling can influence cancer progression. A special focus is on the various recent efforts to therapeutically target the key effectors of the pathway in both preclinical and clinical settings.

Extravesicular TIMP-1 is a non-invasive independent prognostic marker and potential therapeutic target in colorectal liver metastases

Molecular reprogramming of stromal microarchitecture by tumour-derived extracellular vesicles (EVs) is proposed to favour pre-metastatic niche formation. We elucidated the role of extravesicular tissue inhibitor of matrix metalloproteinase-1 (TIMP1^EV) in pro-invasive extracellular matrix (ECM) remodelling of the liver microenvironment to aid tumour progression in colorectal cancer (CRC). Immunohistochemistry analysis revealed a high expression of stromal TIMP1 in the invasion front that was associated with poor progression-free survival in patients with colorectal liver metastases. Molecular analysis identified TIMP1^EV enrichment in CRC-EVs as a major factor in the induction of TIMP1 upregulation in recipient fibroblasts. Mechanistically, we proved that EV-mediated TIMP1 upregulation in recipient fibroblasts induced ECM remodelling. This effect was recapitulated by human serum-derived EVs providing strong evidence that CRC release active EVs into the blood circulation of patients for the horizontal transfer of malignant traits to recipient cells. Moreover, EV-associated TIMP1 binds to HSP90AA, a heat-shock protein, and the inhibition of HSP90AA on human-derived serum EVs attenuates TIMP1^EV-mediated ECM remodelling, rendering EV-associated TIMP1 a potential therapeutic target. Eventually, in accordance with REMARK guidelines, we demonstrated in three independent cohorts that EV-bound TIMP1 is a robust circulating biomarker for a non-invasive, preoperative risk stratification in patients with colorectal liver metastases.

Applications of Extracellular Vesicles in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is the most aggressive and refractory subtype of breast cancer, often occurring in younger patients with poor clinical prognosis. Given the current lack of specific targets for effective intervention, the development of better treatment strategies remains an unmet medical need. Over the last decade, the field of extracellular vesicles (EVs) has grown tremendously, offering immense potential for clinical diagnosis/prognosis and therapeutic applications. While TNBC-EVs have been shown to play an important role in tumorigenesis, chemoresistance and metastasis, they could be repurposed as potential biomarkers for TNBC diagnosis and prognosis. Furthermore, EVs from various cell types can be utilized as nanoscale drug delivery systems (NDDS) for TNBC treatment. Remarkably, EVs generated from specific immune cell subsets have been shown to delay solid tumour growth and reduce tumour burden, suggesting a new immunotherapy approach for TNBC. Intrinsically, EVs can cross the blood-brain barrier (BBB), which holds great potential to treat the brain metastases diagnosed in one third of TNBC patients that remains a substantial clinical challenge. In this review, we present the most recent applications of EVs in TNBC as diagnostic/prognostic biomarkers, nanoscale drug delivery systems and immunotherapeutic agents, as well as discuss the associated challenges and future directions of EVs in cancer immunotherapy.

Tumor-derived extracellular vesicles: The metastatic organotropism drivers

The continuous growing, spreading, and metastasis of tumor cells depend on intercellular communication within cells resident in a tissue environment. Such communication is mediated through the secretion of particles from tumor cells and resident cells known as extracellular vesicles (EVs) within a microenvironment. EVs are a heterogeneous population of membranous vesicles released from tumor cells that transfer many types of active biomolecules to recipient cells and induce physiologic and phenotypic alterations in the tissue environment. Spreading the 'seeds' of metastasis needs the EVs that qualify the 'soil' at distant sites to promote the progress of arriving tumor cells. Growing evidence indicates that EVs have vital roles in tumorigenesis, including pre-metastatic niche formation and organotropic metastasis. These EVs mediate organotropic metastasis by modifying the pre-metastatic microenvironment through different pathways including induction of phenotypic alternation and differentiation of cells, enrolment of distinct supportive stromal cells, up-regulation of the expression of pro-inflammatory genes, and induction of immunosuppressive status. However, instead of pre-metastatic niche formation, evidence suggests that EVs may mediate reawakening of dormant niches. Findings regarding EVs function in tumor metastasis have led to growing interests in the interdisciplinary significance of EVs, including targeted therapy, cell-free therapy, drug-delivery system, and diagnostic biomarker. In this review, we discuss EVs-mediated pre-metastatic niche formation and organotropic metastasis in visceral such as lung, liver, brain, lymph node, and bone with a focus on associated signaling, causing visceral environment hospitable for metastatic cells. Furthermore, we present an overview of the possible therapeutic application of EVs in cancer management.

Liquid Biopsy as a Prognostic and Theranostic Tool for the Management of Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinomas (PDAC) represent one of the deadliest cancers worldwide. Survival is still low due to diagnosis at an advanced stage and resistance to treatment. Herein, we review the main types of liquid biopsy able to help in both prognosis and adaptation of treatments.

CXCL1: Gene, Promoter, Regulation of Expression, mRNA Stability, Regulation of Activity in the Intercellular Space

CXCL1 is one of the most important chemokines, part of a group of chemotactic cytokines involved in the development of many inflammatory diseases. It activates CXCR2 and, at high levels, CXCR1. The expression of CXCL1 is elevated in inflammatory reactions and also has important functions in physiology, including the induction of angiogenesis and recruitment of neutrophils. Due to a lack of reviews that precisely describe the regulation of CXCL1 expression and function, in this paper, we present the mechanisms of CXCL1 expression regulation with a special focus on cancer. We concentrate on the regulation of CXCL1 expression through the regulation of CXCL1 transcription and mRNA stability, including the involvement of NF-κB, p53, the effect of miRNAs and cytokines such as IFN-γ, IL-1β, IL-17, TGF-β and TNF-α. We also describe the mechanisms regulating CXCL1 activity in the extracellular space, including proteolytic processing, CXCL1 dimerization and the influence of the ACKR1/DARC receptor on CXCL1 localization. Finally, we explain the role of CXCL1 in cancer and possible therapeutic approaches directed against this chemokine.

Characterization of surface markers on extracellular vesicles isolated from lymphatic exudate from patients with breast cancer

BACKGROUND

Breast cancer is the most common cancer, and the leading cause of cancer-related deaths, among females world-wide. Recent research suggests that extracellular vesicles (EVs) play a major role in the development of breast cancer metastasis. Axillary lymph node dissection (ALND) is a procedure in patients with known lymph node metastases, and after surgery large amounts of serous fluid are produced from the axilla. The overall aim was to isolate and characterize EVs from axillary serous fluid, and more specifically to determine if potential breast cancer biomarkers could be identified.

METHODS

Lymphatic drain fluid was collected from 7 patients with breast cancer the day after ALND. EVs were isolated using size exclusion chromatography, quantified and detected by nanoparticle tracking analysis, electron microscopy, nano flow cytometry and western blot. The expression of 37 EV surface proteins was evaluated by flow cytometry using the MACSPlex Exosome kit.

RESULTS

Lymphatic drainage exudate retrieved after surgery from all 7 patients contained EVs. The isolated EVs were positive for the typical EV markers CD9, CD63, CD81 and Flotillin-1 while albumin was absent, indicating low contamination from blood proteins. In total, 24 different EV surface proteins were detected. Eleven of those proteins were detected in all patients, including the common EV markers CD9, CD63 and CD81, cancer-related markers CD24, CD29, CD44 and CD146, platelet markers CD41b, CD42a and CD62p as well as HLA-DR/DP/DQ. Furthermore, CD29 and CD146 were enriched in Her2+ patients compared to patients with Her2- tumors.

CONCLUSIONS

Lymphatic drainage exudate retrieved from breast cancer patients after surgery contains EVs that can be isolated using SEC isolation. The EVs have several cancer-related markers including CD24, CD29, CD44 and CD146, proteins of potential interest as biomarkers as well as to increase the understanding of the mechanisms of cancer biology.

Uveal melanoma exosomes induce a pro-metastatic microenvironment through macrophage migration inhibitory factor (MIF)

Uveal melanoma (UM) is a rare melanoma subtype different from cutaneous melanoma, with high incidence of liver metastasis and poor prognosis. Cancer cell derived extracellular vesicles (EVs) have been shown to induce pro-inflammatory and pro-metastatic signaling in the tumor microenvironment and at distant sites. The characterization of UM exosome cargo and its role in metastatic spread is essential to identify targets and intervene in the early stages of metastatic development. Our study characterizes the proteomic content of UM exosomes and identified the presence of markers with metastatic properties. We demonstrated that UM exosomes induce activation of cell signaling pathways and the release of cytokines and growth factors from hepatocytes. These exosome-stimulated liver cells could in turn induce migration of UM cells, confirming that the exosomes have a functional role in the crosstalk between these two cell types. We found that the pro-inflammatory cytokine macrophage migration inhibitory factor (MIF) was a major player in these mechanisms and its blockade inhibited cell migration in co-culture with exosome-stimulated hepatocytes and prevented the development of metastases in vivo. Targeting MIF in the early stages of metastasis may represent a novel adjuvant drug therapy to prevent metastatic spread in uveal melanoma. Implications: This study provides the first in vivo evidence that MIF inhibition may serve as a novel adjuvant drug therapy to prevent metastasis in uveal melanoma.

The multifaceted mechanisms of malignant glioblastoma progression and clinical implications

With the application of high throughput sequencing technologies at single-cell resolution, studies of the tumor microenvironment in glioblastoma, one of the most aggressive and invasive of all cancers, have revealed immense cellular and tissue heterogeneity. A unique extracellular scaffold system adapts to and supports progressive infiltration and migration of tumor cells, which is characterized by altered composition, effector delivery, and mechanical properties. The spatiotemporal interactions between malignant and immune cells generate an immunosuppressive microenvironment, contributing to the failure of effective anti-tumor immune attack. Among the heterogeneous tumor cell subpopulations of glioblastoma, glioma stem cells (GSCs), which exhibit tumorigenic properties and strong invasive capacity, are critical for tumor growth and are believed to contribute to therapeutic resistance and tumor recurrence. Here we discuss the role of extracellular matrix and immune cell populations, major components of the tumor ecosystem in glioblastoma, as well as signaling pathways that regulate GSC maintenance and invasion. We also highlight emerging advances in therapeutic targeting of these components.

Long-Term Cognitive Dysfunction in Cancer Survivors

Cancer-related cognitive impairment (CRCI) is a frequent side effect experienced by an increasing number of cancer survivors with a significant impact on their quality of life. Different definitions and means of evaluation have been used in available literature; hence the exact incidence of CRCI remains unknown. CRCI can be described as cognitive symptoms reported by cancer patients in self-reported questionnaires or as cognitive changes evaluated by formal neuropsychological tests. Nevertheless, association between cognitive symptoms and objectively assessed cognitive changes is relatively weak or absent. Studies have focused especially on breast cancer patients, but CRCI has been reported in multiple types of cancer, including colorectal, lung, ovarian, prostate, testicular cancer and hematological malignancies. While CRCI has been associated with various treatment modalities, including radiotherapy, chemotherapy, hormone therapy and novel systemic therapies, it has been also detected prior to cancer treatment. Therefore, the effects of cancer itself with or without the psychological distress may be involved in the pathogenesis of CRCI as a result of altered coping mechanisms after cancer diagnosis. The development of CRCI is probably multifactorial and the exact mechanisms are currently not completely understood. Possible risk factors include administered treatment, genetic predisposition, age and psychological factors such as anxiety, depression or fatigue. Multiple mechanisms are suggested to be responsible for CRCI, including direct neurotoxic injury of systemic treatment and radiation while other indirect contributing mechanisms are hypothesized. Chronic neuroinflammation mediated by active innate immune system, DNA-damage or endothelial dysfunction is hypothesized to be a central mechanism of CRCI pathogenesis. There is increasing evidence of potential plasma (e.g., damage associated molecular patterns, inflammatory components, circulating microRNAs, exosomes, short-chain fatty acids, and others), cerebrospinal fluid and radiological biomarkers of cognitive dysfunction in cancer patients. Discovery of biomarkers of cognitive impairment is crucial for early identification of cancer patients at increased risk for the development of CRCI or development of treatment strategies to lower the burden of CRCI on long-term quality of life. This review summarizes current literature on CRCI with a focus on long-term effects of different cancer treatments, possible risk factors, mechanisms and promising biomarkers.

Low BACH2 Expression Predicts Adverse Outcome in Chronic Lymphocytic Leukaemia

Chronic lymphocytic leukaemia (CLL) is a heterogeneous disease with a highly variable clinical outcome. There are well-established CLL prognostic biomarkers that have transformed treatment and improved the understanding of CLL biology. Here, we have studied the clinical significance of two crucial B cell regulators, BACH2 (BTB and CNC homology 1, basic leucine zipper transcription factor 2) and BCL6 (B-cell CLL/lymphoma 6), in a cohort of 102 CLL patients and determined the protein interaction networks that they participate in using MEC-1 CLL cells. We observed that CLL patients expressing low levels of BCL6 and BACH2 RNA had significantly shorter overall survival (OS) than high BCL6- and BACH2-expressing cases. Notably, their low expression specifically decreased the OS of immunoglobulin heavy chain variable region-mutated (IGHV-M) CLL patients, as well as those with 11q and 13q deletions. Similar to the RNA data, a low BACH2 protein expression was associated with a significantly shorter OS than a high expression. There was no direct interaction observed between BACH2 and BCL6 in MEC-1 CLL cells, but they shared protein networks that included fifty different proteins. Interestingly, a prognostic index (PI) model that we generated, using integrative risk score values of BACH2 RNA expression, age, and 17p deletion status, predicted patient outcomes in our cohort. Taken together, these data have shown for the first time a possible prognostic role for BACH2 in CLL and have revealed protein interaction networks shared by BCL6 and BACH2, indicating a significant role for BACH2 and BCL6 in key cellular processes, including ubiquitination mediated B-cell receptor functions, nucleic acid metabolism, protein degradation, and homeostasis in CLL biology.

A proposed Information-Based modality for the treatment of cancer

Treatment modalities for cancer involve physical manipulations such as surgery, immunology, radiation, chemotherapy or gene editing. This is a proposal for an information-based modality. This modality does not change the internal state of the cancer cell directly - instead, the cancer cell is manipulated by giving it information to instruct the cell to perform an action. This modality is based on a theory of Structure Encoding in DNA, where information about body part structure controls the epigenetic state of cells in the process of development from pluripotent cells to fully differentiated cells. It has been noted that cancer is often due to errors in morphogenetic differentiation accompanied by associated epigenetic processes. This implies a model of cancer called the Epigenetic Differentiation Model. A major feature of the Structure Encoding Theory is that the characteristics of the differentiated cell are affected by inter-cellular information passed in the tissue microenvironment, which specifies the exact location of a cell in a body part structure. This is done by exosomes that carry fragments of long non-coding RNA and transposons, which convey structure information. In the normal process of epigenetic differentiation, the information passed may lead to apoptosis due to the constraints of a particular body part structure. The proposed treatment involves determining what structure information is being passed in a particular tumor, then adding artificial exosomes that overwhelm the current information with commands for the cells to go into apoptosis.

Exosomes: Small vesicles with big roles in cancer, vaccine development, and therapeutics

Cancer is a deadly disease that is globally and consistently one of the leading causes of mortality every year. Despite the availability of chemotherapy, radiotherapy, immunotherapy, and surgery, a cure for cancer has not been attained. Recently, exosomes have gained significant attention due to the therapeutic potential of their various components including proteins, lipids, nucleic acids, miRNAs, and lncRNAs. Exosomes constitute a set of tiny extracellular vesicles with an approximate diameter of 30-100 nm. They are released from different cells and are present in biofluids including blood, cerebrospinal fluid (CSF), and urine. They perform crucial multifaceted functions in the malignant progression of cancer via autocrine, paracrine, and endocrine communications. The ability of exosomes to carry different cargoes including drug and molecular information to recipient cells make them a novel tool for cancer therapeutics. In this review, we discuss the major components of exosomes and their role in cancer progression. We also review important literature about the potential role of exosomes as vaccines and delivery carriers in the context of cancer therapeutics.

A Multivariate Diagnostic Model Based on Urinary EpCAM-CD9-Positive Extracellular Vesicles for Prostate Cancer Diagnosis

Introduction

Prostate cancer (PCa) is one of the most frequently diagnosed cancers and the leading cause of cancer death in males worldwide. Although prostate-specific antigen (PSA) screening has considerably improved the detection of PCa, it has also led to a dramatic increase in overdiagnosing indolent disease due to its low specificity. This study aimed to develop and validate a multivariate diagnostic model based on the urinary epithelial cell adhesion molecule (EpCAM)-CD9-positive extracellular vesicles (EVs) (uEV_EpCAM-CD9) to improve the diagnosis of PCa.

Methods

We investigated the performance of uEV_EpCAM-CD9 from urine samples of 193 participants (112 PCa patients, 55 benign prostatic hyperplasia patients, and 26 healthy donors) to diagnose PCa using our laboratory-developed chemiluminescent immunoassay. We applied machine learning to training sets and subsequently evaluated the multivariate diagnostic model based on uEV_EpCAM-CD9 in validation sets.

Results

Results showed that uEV_EpCAM-CD9 was able to distinguish PCa from controls, and a significant decrease of uEV_EpCAM-CD9 was observed after prostatectomy. We further used a training set (N = 116) and constructed an exclusive multivariate diagnostic model based on uEV_EpCAM-CD9, PSA, and other clinical parameters, which showed an enhanced diagnostic sensitivity and specificity and performed excellently to diagnose PCa [area under the curve (AUC) = 0.952, P < 0.0001]. When applied to a validation test (N = 77), the model achieved an AUC of 0.947 (P < 0.0001). Moreover, this diagnostic model also exhibited a superior diagnostic performance (AUC = 0.917, P < 0.0001) over PSA (AUC = 0.712, P = 0.0018) at the PSA gray zone.

Conclusions

The multivariate model based on uEV_EpCAM-CD9 achieved a notable diagnostic performance to diagnose PCa. In the future, this model may potentially be used to better select patients for prostate transrectal ultrasound (TRUS) biopsy.

HLA-G/sHLA-G and HLA-G-Bearing Extracellular Vesicles in Cancers: Potential Role as Biomarkers

As a non-classic major histocompatibility complex (MHC) class I molecule, human leukocyte antigen G (HLA-G) is expressed in fetal-maternal interface and immunoprivileged site only in healthy condition, and in pathological conditions such as cancer, it can be de novo expressed. It is now widely accepted that HLA-G is a key molecule in the process of immune escape of cancer cells, which is ubiquitously expressed in the tumor environment. This raises the possibility that it may play an adverse role in tumor immunity. The expression level of HLA-G has been demonstrated to be highly correlated with clinical parameters in many tumors, and its potential significance in the diagnosis and prognosis of cancer has been postulated. However, because HLA-G itself has up to seven different subtypes, and for some subtypes, detected antibodies are few or absent, it is hard to evaluate the actual expression of HLA-G in tumors. In the present work, we described (a) the structure and three main forms of HLA-G, (b) summarized the mechanism of HLA-G in the immune escape of tumor cells, (c) discussed the potential role of HLA-G as a tumor marker, and reviewed (d) the methods for detecting and quantifying HLA-G.

Mutual Modulation Between Extracellular Vesicles and Mechanoenvironment in Bone Tumors

The bone microenvironment homeostasis is guaranteed by the balanced and fine regulated bone matrix remodeling process. This equilibrium can be disrupted by cancer cells developed in the bone (primary bone cancers) or deriving from other tissues (bone metastatic lesions), through a mechanism by which they interfere with bone cells activities and alter the microenvironment both biochemically and mechanically. Among the factors secreted by cancer cells and by cancer-conditioned bone cells, extracellular vesicles (EVs) are described to exert pivotal roles in the establishment and the progression of bone cancers, by conveying tumorigenic signals targeting and transforming normal cells. Doing this, EVs are also responsible in modulating the production of proteins involved in regulating matrix stiffness and/or mechanotransduction process, thereby altering the bone mechanoenvironment. In turn, bone and cancer cells respond to deregulated matrix stiffness by modifying EV production and content, fueling the vicious cycle established in tumors. Here, we summarized the relationship between EVs and the mechanoenvironment during tumoral progression, with the final aim to provide some innovative perspectives in counteracting bone cancers.

Remodeling of Membrane Shape and Topology by Curvature Elasticity and Membrane Tension

Cellular membranes exhibit a fascinating variety of different morphologies, which are continuously remodeled by transformations of membrane shape and topology. This remodeling is essential for important biological processes (cell division, intracellular vesicle trafficking, endocytosis) and can be elucidated in a systematic and quantitative manner using synthetic membrane systems. Here, recent insights obtained from such synthetic systems are reviewed, integrating experimental observations and molecular dynamics simulations with the theory of membrane elasticity. The study starts from the polymorphism of biomembranes as observed for giant vesicles by optical microscopy and small nanovesicles in simulations. This polymorphism reflects the unusual elasticity of fluid membranes and includes the formation of membrane necks or fluid 'worm holes'. The proliferation of membrane necks generates stable multi-spherical shapes, which can form tubules and tubular junctions. Membrane necks are also essential for the remodeling of membrane topology via membrane fission and fusion. Neck fission can be induced by fine-tuning of membrane curvature, which leads to the controlled division of giant vesicles, and by adhesion-induced membrane tension as observed for small nanovesicles. Challenges for future research include the interplay of curvature elasticity and membrane tension during membrane fusion and the localization of fission and fusion processes within intramembrane domains.

The multifaceted involvement of exosomes in tumor progression: Induction and inhibition

As key performers in intercellular communication, exosomes released by tumor cells play an important role in cancer development, including angiogenesis, cancer‐associated fibroblasts activation, epithelial‐mesenchymal transformation (EMT), immune escape, and pre‐metastatic niche formation. Meanwhile, other cells in tumor microenvironment (TME) can secrete exosomes and facilitate tumor progression. Elucidating mechanisms regarding these processes may offer perspectives for exosome‐based antitumor strategies. In this review, we mainly introduce the versatile roles of tumor or stromal cell derived exosomes in cancer development, with a particular focus on the biological capabilities and functionalities of their diverse contents, such as miRNAs, lncRNAs, and circRNAs. The potential clinical application of exosomes as biomarkers in cancer diagnosis and prognosis is also discussed. Finally, the current antitumor strategies based on exosomes in immunotherapy and targeted delivery for chemotherapeutic or biological agents are summarized.

State-of-the-Art: Exosomes in Colorectal Cancer

Colorectal cancer (CRC) has a high prevalence and mortality rate, globally. To date, the progression mechanisms of CRC are still elusive. Exosomes (~100 nm in diameter) correspond to a subset of extracellular vesicles formed by an array of cancerous cells and stromal cells. These particular nanovesicles carry and transmit bioactive molecules, like proteins, lipids, and genetic materials, which mediate the crosstalk between cancer cells and the microenvironment. Accumulating evidence has shown the decisive functions of exosomes in the development, metastasis, and therapy resistance of CRC. Furthermore, some recent studies have also revealed the abilities of exosomes to function as either biomarkers or therapeutic targets for CRC. This review focuses on the specific mechanisms of exosomes in regulating CRC progression, and summarizes the potential clinical applications of exosomes in the diagnosis and therapy of CRC.

Small extracellular vesicles in cancer

Extracellular vesicles (EV) are lipid-bilayer enclosed vesicles in submicron size that are released from cells. A variety of molecules, including proteins, DNA fragments, RNAs, lipids, and metabolites can be selectively encapsulated into EVs and delivered to nearby and distant recipient cells. In tumors, through such intercellular communication, EVs can regulate initiation, growth, metastasis and invasion of tumors. Recent studies have found that EVs exhibit specific expression patterns which mimic the parental cell, providing a fingerprint for early cancer diagnosis and prognosis as well as monitoring responses to treatment. Accordingly, various EV isolation and detection technologies have been developed for research and diagnostic purposes. Moreover, natural and engineered EVs have also been used as drug delivery nanocarriers, cancer vaccines, cell surface modulators, therapeutic agents and therapeutic targets. Overall, EVs are under intense investigation as they hold promise for pathophysiological and translational discoveries. This comprehensive review examines the latest EV research trends over the last five years, encompassing their roles in cancer pathophysiology, diagnostics and therapeutics. This review aims to examine the full spectrum of tumor-EV studies and provide a comprehensive foundation to enhance the field. The topics which are discussed and scrutinized in this review encompass isolation techniques and how these issues need to be overcome for EV-based diagnostics, EVs and their roles in cancer biology, biomarkers for diagnosis and monitoring, EVs as vaccines, therapeutic targets, and EVs as drug delivery systems. We will also examine the challenges involved in EV research and promote a framework for catalyzing scientific discovery and innovation for tumor-EV-focused research.