New Insights Into the Regulatory Roles of Extracellular Vesicles in Tumor Angiogenesis and Their Clinical Implications

Platelet-derived extracellular vesicle drug delivery system loaded with kaempferol for treating corneal neovascularization

Platelet-derived extracellular vesicles (PEVs) have drawn attention due to their multifunctionality, ease of procurement, and abundant supply from clinical-grade platelet concentrates. PEVs can be readily endocytosed due to their lipid bilayer membrane and nanoscale structure, enhancing the bioavailability and efficacy of their therapeutic effects. PEVs also contain various trophic factors that enhance their effectiveness as therapeutic agents. Given that nanomedicine provides benefits over traditional treatments for eye diseases by surpassing physical ocular barriers, PEVs combined with the anti-angiogenic agent, kaempferol (KM), were assessed for their capacity to inhibit abnormal blood vessel formation in the cornea. Characterization of the nanoparticles suggested the successful preparation of KM-loaded PEVs (PEV-KM) with a mean diameter of approximately 160 nm and an encapsulation efficiency of around 61 %. PEV-KM was effectively internalized into human vascular endothelial cells, resulting in inhibited function, as evidenced by lower wound closure rates, decreased tube formation capacity, and downregulation of angiogenesis-related gene expression. Moreover, prolonged ocular retention was observed following the topical application of PEV and PEV-KM in mouse eyes. In an alkali-burned corneal neovascularization (CoNV) mouse model, PEV (1 %) was found to decrease vessel formation in the injured cornea. However, the combination of PEV and KM (1 % PEV with KM 6 μg/mL) showed an even stronger effect in inhibiting CoNV and decreasing the expression of proangiogenic and inflammatory cytokines. Overall, our data suggests that the topical administration of PEVs, either alone or alongside KM (PEV-KM), is a promising therapy for the management of CoNV.

The biological function of extracellular vesicles in prostate cancer and their clinical application as diagnostic and prognostic biomarkers

Prostate cancer (PCa) is one of the most commonly diagnosed malignancies and main causes of cancer-related deaths worldwide. It is characterized by high heterogeneity, ranging from slow-growing tumor to metastatic disease. Since both therapy selection and outcome strongly rely on appropriate patient stratification, it is crucial to differentiate benign from more aggressive conditions using new and improved diagnostic and prognostic biomarkers. Extracellular vesicles (EVs) are membrane-coated particles carrying a specific biological cargo composed of nucleic acids, proteins, and metabolites. Here, we provide an overview of the role of EVs in PCa, focusing on both their biological function and clinical value. Specifically, we summarize the oncogenic role of EVs in mediating the interactions with PCa microenvironment as well as the horizontal transfer of metastatic traits and drug resistance between PCa cells. Furthermore, we discuss the potential usage of EVs as innovative tools for PCa diagnosis and prognosis.

Extracellular vesicles in neuroblastoma: role in progression, resistance to therapy and diagnostics

Neuroblastoma (NB) is the most common extracranial solid pediatric cancer, and is one of the leading causes of cancer-related deaths in children. Despite the current multi-modal treatment regimens, majority of patients with advanced-stage NBs develop therapeutic resistance and relapse, leading to poor disease outcomes. There is a large body of knowledge on pathophysiological role of small extracellular vesicles (EVs) in progression and metastasis of multiple cancer types, however, the importance of EVs in NB was until recently not well understood. Studies emerging in the last few years have demonstrated the involvement of EVs in various aspects of NB pathogenesis. In this review we summarize these recent findings and advances on the role EVs play in NB progression, such as tumor growth, metastasis and therapeutic resistance, that could be helpful for future investigations in NB EV research. We also discuss different strategies for therapeutic targeting of NB-EVs as well as utilization of NB-EVs as potential biomarkers.

Label-free nonlinear optical signatures of extracellular vesicles in liquid and tissue biopsies of human breast cancer

Extracellular vesicles (EVs) have been implicated in metastasis and proposed as cancer biomarkers. However, heterogeneity and small size makes assessments of EVs challenging. Often, EVs are isolated from biofluids, losing spatial and temporal context and thus lacking the ability to access EVs in situ in their native microenvironment. This work examines the capabilities of label-free nonlinear optical microscopy to extract biochemical optical metrics of EVs in ex vivo tissue and EVs isolated from biofluids in cases of human breast cancer, comparing these metrics within and between EV sources. Before surgery, fresh urine and blood serum samples were obtained from human participants scheduled for breast tumor surgery (24 malignant, 6 benign) or healthy participants scheduled for breast reduction surgery (4 control). EVs were directly imaged both in intact ex vivo tissue that was removed during surgery and in samples isolated from biofluids by differential ultracentrifugation. Isolated EVs and freshly excised ex vivo breast tissue samples were imaged with custom nonlinear optical microscopes to extract single-EV optical metabolic signatures of NAD(P)H and FAD autofluorescence. Optical metrics were significantly altered in cases of malignant breast cancer in biofluid-derived EVs and intact tissue EVs compared to control samples. Specifically, urinary isolated EVs showed elevated NAD(P)H fluorescence lifetime in cases of malignant cancer, serum-derived isolated EVs showed decreased optical redox ratio in stage II cancer, but not earlier stages, and ex vivo breast tissue showed an elevated number of EVs in cases of malignant cancer. Results further indicated significant differences in the measured optical metabolic signature based on EV source (urine, serum and tissue) within individuals.

Intramyocardial Injection of Hypoxia-Conditioned Extracellular Vesicles Modulates Response to Oxidative Stress in the Chronically Ischemic Myocardium

INTRODUCTION

Patients with advanced coronary artery disease (CAD) who are not eligible for stenting or surgical bypass procedures have limited treatment options. Extracellular vesicles (EVs) have emerged as a potential therapeutic target for the treatment of advanced CAD. These EVs can be conditioned to modify their contents. In our previous research, we demonstrated increased perfusion, decreased inflammation, and reduced apoptosis with intramyocardial injection of hypoxia-conditioned EVs (HEVs). The goal of this study is to further understand the function of HEVs by examining their impact on oxidative stress using our clinically relevant and extensively validated swine model of chronic myocardial ischemia.

METHODS

Fourteen Yorkshire swine underwent a left thoracotomy for the placement of an ameroid constrictor on the left circumflex coronary artery to model chronic myocardial ischemia. After two weeks of recovery, the swine underwent a redo thoracotomy with injection of either HEVs (n = 7) or a saline control (CON, n = 7) into the ischemic myocardium. Five weeks after injection, the swine were subjected to terminal harvest. Protein expression was measured using immunoblotting. OxyBlot analysis and 3-nitrotyrosine staining were used to quantify total oxidative stress.

RESULTS

There was a significant increase in myocardial expression of the antioxidants SOD 2, GPX-1, HSF-1, UCP-2, catalase, and HO-1 (all p ≤ 0.05) in the HEV group when compared to control animals. The HEVs also exhibited a significant increase in pro-oxidant NADPH oxidase (NOX) 1, NOX 3, p47phox, and p67phox (all p ≤ 0.05). However, no change was observed in the expression of NFkB, KEAP 1, and PRDX1 (all p > 0.05) between the HEV and CON groups. There were no significant differences in total oxidative stress as determined by OxyBlot and 3-nitrotyrosine staining (p = 0.64, p = 0.32) between the groups.

CONCLUSIONS

Administration of HEVs in ischemic myocardium induces a significant increase in pro- and antioxidant proteins without a net change in total oxidative stress. These findings suggest that HEV-induced changes in redox signaling pathways may play a role in increased perfusion, decreased inflammation, and reduced apoptosis in ischemic myocardium. Further studies are required to determine if HEVs alter the net oxidative stress in ischemic myocardium at an earlier time point of HEV administration.

Extracellular Vesicles' Role in Angiogenesis and Altering Angiogenic Signaling

Angiogenesis, the process of new blood vessels formation from existing vasculature, plays a vital role in development, wound healing, and various pathophysiological conditions. In recent years, extracellular vesicles (EVs) have emerged as crucial mediators in intercellular communication and have gained significant attention for their role in modulating angiogenic processes. This review explores the multifaceted role of EVs in angiogenesis and their capacity to modulate angiogenic signaling pathways. Through comprehensive analysis of a vast body of literature, this review highlights the potential of utilizing EVs as therapeutic tools to modulate angiogenesis for both physiological and pathological purposes. A good understanding of these concepts holds promise for the development of novel therapeutic interventions targeting angiogenesis-related disorders.

Tanshinone IIA promotes vascular normalization and boosts Sorafenib's anti-hepatoma activity via modulating the PI3K-AKT pathway

Introduction: Angiogenesis is an essential feature of liver cancer. Tumor hypoxia results from abnormal vessel architecture. Numerous studies have sufficiently demonstrated that Tanshinone IIA (Tan IIA) can increase blood flow and enhance microcirculation. The objectives of this study are to: 1 assess the impact of Tan IIA on tumor angiogenesis and architecture, 2 determine the impact of Tan IIA on tumor hypoxia and susceptibility to Sorafenib, and 3 clarify the relevant mechanisms. Methods: CCK8 and flow cytometry measured cell proliferation and apoptosis, respectively. Tube creation assay was used to investigate medication effects on angiogenesis and structure. Drug effects on tumor development, metastasis, and hypoxic tumor microenvironment are assessed in an orthotopic xenograft model of liver tumors. Protein expression was measured by Western blotting and immunohistochemistry. Results: Our results demonstrated that Tan IIA could not reduce tumor proliferation or enhance Sorafenib's anti-tumor effect in vitro. Nevertheless, it can prevent Sorafenib from demolishing the typical vascular structure and aid sorafenib in blocking the recruitment of vascular endothelial cells by liver cancer cells. Although Tan IIA cannot inhibit tumor growth in vivo, it can significantly boost Sorafenib's inhibitory effect on liver cancer, alleviate tumor microenvironment hypoxia, and minimize lung metastasis. This effect may be achieved by reducing HIF-1α and HIF-2α expression via the PI3K-AKT signal pathway. Discussion: Our results reveal the mechanism of Tan IIA in normalizing tumor blood vessels, provide innovative concepts and approaches to overcome chemotherapy resistance, and provide a theoretical basis for the clinical transformation and usage of Tan IIA.

The Composition of Small Extracellular Vesicles (sEVs) in the Blood Plasma of Colorectal Cancer Patients Reflects the Presence of Metabolic Syndrome and Correlates with Angiogenesis and the Effectiveness of Thermoradiation Therapy

The majority of colorectal cancer patients (CRCPs) develop tumors on the background of "metabolically healthy obesity" or metabolic syndrome. The aim of the work was to study the levels of matrix metalloproteinases (MMPs) and heat shock proteins (HSPs) on the surface of blood plasma CD9-positive and FABP4-positive small extracellular vesicles (sEVs) from CRCPs depending on metabolic status and tumor angiogenesis, as well as to evaluate the sEVs markers as predictors of the effectiveness of thermoradiotherapy. In CRCPs, compared with patients with colorectal polyps (CPPs), the proportion of triple positive EVs and EVs with the MMP9+MMP2-TIMP1+ phenotype increased significantly among FABP4-positive EVs (adipocyte-derived EVs), which in general may indicate the overexpression of MMP9 and TIMP1 by adipocytes or adipose tissue macrophages in CRCPs. The results obtained have prospects for use as markers to clarify cancer risk in CPPs. One can assume that for CRCPs with metabolic syndrome or metabolically healthy obesity, it is the FABP4+MMP9+MMP2-TIMP1- population of circulating sEVs that is the most optimal biomarker reflecting tumor angiogenesis. Determining this population in the blood will be useful in monitoring patients after treatment for the early detection of tumor progression. CD9+MMP9+MMP2-TIMP1- and MMP9+MMP2-TIMP1+ subpopulations of circulating sEVs are the most promising predictors of the efficacy of thermoradiation therapy because their levels at baseline differ significantly in CRCPs with different tumor responses.

Therapy resistance in neuroblastoma: Mechanisms and reversal strategies

Neuroblastoma is one of the most common pediatric solid tumors that threaten the health of children, accounting for about 15% of childhood cancer-related mortality in the United States. Currently, multiple therapies have been developed and applied in clinic to treat neuroblastoma including chemotherapy, radiotherapy, targeted therapy, and immunotherapy. However, the resistance to therapies is inevitable following long-term treatment, leading to treatment failure and cancer relapse. Hence, to understand the mechanisms of therapy resistance and discover reversal strategies have become an urgent task. Recent studies have demonstrated numerous genetic alterations and dysfunctional pathways related to neuroblastoma resistance. These molecular signatures may be potential targets to combat refractory neuroblastoma. A number of novel interventions for neuroblastoma patients have been developed based on these targets. In this review, we focus on the complicated mechanisms of therapy resistance and the potential targets such as ATP-binding cassette transporters, long non-coding RNAs, microRNAs, autophagy, cancer stem cells, and extracellular vesicles. On this basis, we summarized recent studies on the reversal strategies to overcome therapy resistance of neuroblastoma such as targeting ATP-binding cassette transporters, MYCN gene, cancer stem cells, hypoxia, and autophagy. This review aims to provide novel insight in how to improve the therapy efficacy against resistant neuroblastoma, which may shed light on the future directions that would enhance the treatment outcomes and prolong the survival of patients with neuroblastoma.

Current Status of Research on Small Extracellular Vesicles for the Diagnosis and Treatment of Urological Tumors

Extracellular vesicles (EVs) are important mediators of communication between tumor cells and normal cells. These vesicles are rich in a variety of contents such as RNA, DNA, and proteins, and can be involved in angiogenesis, epithelial-mesenchymal transition, the formation of pre-metastatic ecological niches, and the regulation of the tumor microenvironment. Small extracellular vesicles (sEVs) are a type of EVs. Currently, the main treatments for urological tumors are surgery, radiotherapy, and targeted therapy. However, urological tumors are difficult to diagnose and treat due to their high metastatic rate, tendency to develop drug resistance, and the low sensitivity of liquid biopsies. Numerous studies have shown that sEVs offer novel therapeutic options for tumor treatment, such as tumor vaccines and tumor drug carriers. sEVs have attracted a great deal of attention owing to their contribution to in intercellular communication, and as novel biomarkers, and role in the treatment of urological tumors. This article reviews the research and applications of sEVs in the diagnosis and treatment of urological tumors.

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.

Tumor-derived small extracellular vesicles: potential roles and mechanism in glioma

Small extracellular vesicles (SEVs) are extracellular vesicles containing DNA, RNA, and proteins and are involved in intercellular communication and function, playing an essential role in the growth and metastasis of tumors. SEVs are present in various body fluids and can be isolated and extracted from blood, urine, and cerebrospinal fluid. Under both physiological and pathological conditions, SEVs can be released by some cells, such as immune, stem, and tumor cells, in a cytosolic manner. SEVs secreted by tumor cells are called tumor-derived exosomes (TEXs) because of their origin in the corresponding parent cells. Glioma is the most common intracranial tumor, accounting for approximately half of the primary intracranial tumors, and is characterized by insidious onset, high morbidity, and high mortality rate. Complete removal of tumor tissues by surgery is difficult. Chemotherapy can improve the survival quality of patients to a certain extent; however, gliomas are prone to chemoresistance, which seriously affects the prognosis of patients. In recent years, TEXs have played a vital role in the occurrence, development, associated immune response, chemotherapy resistance, radiation therapy resistance, and metastasis of glioma. This article reviews the role of TEXs in glioma progression, drug resistance, and clinical diagnosis.

New insights into antiangiogenic therapy resistance in cancer: Mechanisms and therapeutic aspects

Angiogenesis is a hallmark of cancer and is required for tumor growth and progression. Antiangiogenic therapy has been revolutionarily developing and was approved for the treatment of various types of cancer for nearly two decades, among which bevacizumab and sorafenib continue to be the two most frequently used antiangiogenic drugs. Although antiangiogenic therapy has brought substantial survival benefits to many cancer patients, resistance to antiangiogenic drugs frequently occurs during clinical treatment, leading to poor outcomes and treatment failure. Cumulative evidence has demonstrated that the intricate interplay among tumor cells, bone marrow-derived cells, and local stromal cells critically allows for tumor escape from antiangiogenic therapy. Currently, drug resistance has become the main challenge that hinders the therapeutic efficacies of antiangiogenic therapy. In this review, we describe and summarize the cellular and molecular mechanisms conferring tumor drug resistance to antiangiogenic therapy, which was predominantly associated with redundancy in angiogenic signaling molecules (e.g., VEGFs, GM-CSF, G-CSF, and IL17), alterations in biological processes of tumor cells (e.g., tumor invasiveness and metastasis, stemness, autophagy, metabolic reprogramming, vessel co-option, and vasculogenic mimicry), increased recruitment of bone marrow-derived cells (e.g., myeloid-derived suppressive cells, tumor-associated macrophages, and tumor-associated neutrophils), and changes in the biological functions and features of local stromal cells (e.g., pericytes, cancer-associated fibroblasts, and endothelial cells). We also review potential biomarkers to predict the response to antiangiogenic therapy in cancer patients, which mainly consist of imaging biomarkers, cellular and extracellular proteins, a certain type of bone marrow-derived cells, local stromal cell content (e.g., pericyte coverage) as well as serum or plasma biomarkers (e.g., non-coding RNAs). Finally, we highlight the recent advances in combination strategies with the aim of enhancing the response to antiangiogenic therapy in cancer patients and mouse models. This review introduces a comprehensive understanding of the mechanisms and biomarkers associated with the evasion of antiangiogenic therapy in cancer, providing an outlook for developing more effective approaches to promote the therapeutic efficacy of antiangiogenic therapy.