Induction Of Angiogenesis Research Articles

Metastatic Dissemination: Role of Tumor-Derived Extracellular Vesicles and Their Use as Clinical Biomarkers.

Cancer is a major cause of mortality in humans; often, rather than the primary tumor, it is the presence of metastases that are the cause of death. Extracellular vesicles (EVs) are small structures released by both normal and cancer cells; regarding the latter, they have been demonstrated to modulate almost all cancer-related processes, such as invasion, angiogenesis induction, drug resistance, and immune evasion. In the last years, it has become clear how EVs are widely involved in metastatic dissemination as well as in pre-metastatic niche (PMN) formation. Indeed, in order to achieve a successful metastatic process, i.e., penetration by cancer cells into distant tissues, the shaping of a favorable environment into those distant tissue, i.e., PMN formation, is mandatory. This process consists of an alteration that takes place in a distant organ and paves the way for the engraftment and growth of circulating tumor cells derived from the tumor primary site. This review focuses on the role of EVs in pre-metastatic niche formation and metastatic dissemination, also reporting the last studies suggesting the EVs role as biomarkers of metastatic diseases, possibly in a liquid biopsy approach.

Incongruence between transcriptional and vascular pathophysiological cell states

The Notch pathway is a major regulator of endothelial transcriptional specification. Targeting the Notch receptors or Delta-like ligand 4 (Dll4) dysregulates angiogenesis. Here, by analyzing single and compound genetic mutants for all Notch signaling members, we find significant differences in the way ligands and receptors regulate liver vascular homeostasis. Loss of Notch receptors caused endothelial hypermitogenic cell-cycle arrest and senescence. Conversely, Dll4 loss triggered a strong Myc-driven transcriptional switch inducing endothelial proliferation and the tip-cell state. Myc loss suppressed the induction of angiogenesis in the absence of Dll4, without preventing the vascular enlargement and organ pathology. Similarly, inhibition of other pro-angiogenic pathways, including MAPK/ERK and mTOR, had no effect on the vascular expansion induced by Dll4 loss; however, anti-VEGFA treatment prevented it without fully suppressing the transcriptional and metabolic programs. This study shows incongruence between single-cell transcriptional states, vascular phenotypes and related pathophysiology. Our findings also suggest that the vascular structure abnormalization, rather than neoplasms, causes the reported anti-Dll4 antibody toxicity.

SRF617 Is a Potent Inhibitor of CD39 with Immunomodulatory and Antitumor Properties.

CD39 (ENTPD1) is a key enzyme responsible for degradation of extracellular ATP and is upregulated in the tumor microenvironment (TME). Extracellular ATP accumulates in the TME from tissue damage and immunogenic cell death, potentially initiating proinflammatory responses that are reduced by the enzymatic activity of CD39. Degradation of ATP by CD39 and other ectonucleotidases (e.g., CD73) results in extracellular adenosine accumulation, constituting an important mechanism for tumor immune escape, angiogenesis induction, and metastasis. Thus, inhibiting CD39 enzymatic activity can inhibit tumor growth by converting a suppressive TME to a proinflammatory environment. SRF617 is an investigational, anti-CD39, fully human IgG4 Ab that binds to human CD39 with nanomolar affinity and potently inhibits its ATPase activity. In vitro functional assays using primary human immune cells demonstrate that inhibiting CD39 enhances T-cell proliferation, dendritic cell maturation/activation, and release of IL-1β and IL-18 from macrophages. In vivo, SRF617 has significant single-agent antitumor activity in human cell line-derived xenograft models that express CD39. Pharmacodynamic studies demonstrate that target engagement of CD39 by SRF617 in the TME inhibits ATPase activity, inducing proinflammatory mechanistic changes in tumor-infiltrating leukocytes. Syngeneic tumor studies using human CD39 knock-in mice show that SRF617 can modulate CD39 levels on immune cells invivo and can penetrate the TME of an orthotopic tumor, leading to increased CD8+ T-cell infiltration. Targeting CD39 is an attractive approach for treating cancer, and, as such, the properties of SRF617 make it an excellent drug development candidate.

Top-down design of protein architectures with reinforcement learning.

As a result of evolutionary selection, the subunits of naturally occurring protein assemblies often fit together with substantial shape complementarity to generate architectures optimal for function in a manner not achievable by current design approaches. We describe a "top-down" reinforcement learning-based design approach that solves this problem using Monte Carlo tree search to sample protein conformers in the context of an overall architecture and specified functional constraints. Cryo-electron microscopy structures of the designed disk-shaped nanopores and ultracompact icosahedra are very close to the computational models. The icosohedra enable very-high-density display of immunogens and signaling molecules, which potentiates vaccine response and angiogenesis induction. Our approach enables the top-down design of complex protein nanomaterials with desired system properties and demonstrates the power of reinforcement learning in protein design.

Altered Glycosylation in Progression and Management of Bladder Cancer.

Bladder cancer (BC) is the 10th most common malignancy worldwide, with an estimated 573,000 new cases and 213,000 deaths in 2020. Available therapeutic approaches are still unable to reduce the incidence of BC metastasis and the high mortality rates of BC patients. Therefore, there is a need to deepen our understanding of the molecular mechanisms underlying BC progression to develop new diagnostic and therapeutic tools. One such mechanism is protein glycosylation. Numerous studies reported changes in glycan biosynthesis during neoplastic transformation, resulting in the appearance of the so-called tumor-associated carbohydrate antigens (TACAs) on the cell surface. TACAs affect a wide range of key biological processes, including tumor cell survival and proliferation, invasion and metastasis, induction of chronic inflammation, angiogenesis, immune evasion, and insensitivity to apoptosis. The purpose of this review is to summarize the current information on how altered glycosylation of bladder cancer cells promotes disease progression and to present the potential use of glycans for diagnostic and therapeutic purposes.

VSSP-activated macrophages mediate senescence and tumor inhibition in a preclinical model of advanced prostate cancer

Androgen deprivation therapy (ADT) is a standard therapy for prostate cancer (PCa). Though disseminated disease is initially sensitive to ADT, an important fraction of the patients progresses to castration-resistant prostate cancer (CRPC). For this reason, the identification of novel effective therapies for treating CRPC is needed. Immunotherapeutic strategies focused on macrophages as antitumor effectors, directly enhancing their tumoricidal potential at the tumor microenvironment or their adoptive transfer after ex vivo activation, have arisen as promising therapies in several cancer types. Despite several approaches centered on the activation of tumor-associated macrophages (TAMs) in PCa are under investigation, to date there is no evidence of clinical benefit in patients. In addition, the evidence of the effectiveness of macrophage adoptive transfer on PCa is poor. Here we find that VSSP, an immunomodulator of the myeloid system, decreases TAMs and inhibits prostatic tumor growth when administered to castrated Pten-deficient prostate tumor-bearing mice. In mice bearing castration-resistant Ptenpc−/−; Trp53pc−/− tumors, VSSP administration showed no effect. Nevertheless, adoptive transfer of macrophages activated ex vivo with VSSP inhibited Ptenpc−/−; Trp53pc−/− tumor growth through reduction of angiogenesis and tumor cell proliferation and induction of senescence. Taken together, our results highlight the rationale of exploiting macrophage functional programming as a promising strategy for CRPC therapy, with particular emphasis on ex vivo-activated proinflammatory macrophage adoptive transfer.Graphical abstract5rwXuKXp78386xwRRkt56hVideo abstract

On the Role of Glycolysis in Early Tumorigenesis—Permissive and Executioner Effects

Reprogramming energy production from mitochondrial respiration to glycolysis is now considered a hallmark of cancer. When tumors grow beyond a certain size they give rise to changes in their microenvironment (e.g., hypoxia, mechanical stress) that are conducive to the upregulation of glycolysis. Over the years, however, it has become clear that glycolysis can also associate with the earliest steps of tumorigenesis. Thus, many of the oncoproteins most commonly involved in tumor initiation and progression upregulate glycolysis. Moreover, in recent years, considerable evidence has been reported suggesting that upregulated glycolysis itself, through its enzymes and/or metabolites, may play a causative role in tumorigenesis, either by acting itself as an oncogenic stimulus or by facilitating the appearance of oncogenic mutations. In fact, several changes induced by upregulated glycolysis have been shown to be involved in tumor initiation and early tumorigenesis: glycolysis-induced chromatin remodeling, inhibition of premature senescence and induction of proliferation, effects on DNA repair, O-linked N-acetylglucosamine modification of target proteins, antiapoptotic effects, induction of epithelial-mesenchymal transition or autophagy, and induction of angiogenesis. In this article we summarize the evidence that upregulated glycolysis is involved in tumor initiation and, in the following, we propose a mechanistic model aimed at explaining how upregulated glycolysis may play such a role.

The Role of Cytokines, Chemokines and NFkB in Inflammation and Cancer

Previous researches have suggested that chronic inflammation plays a critical role in cancer pathogenesis as it has been assessed that underlying infections and inflammatory responses have been associated with 25% of all cancer cases, whereas the inflammatory microenvironment is an essential component of all tumors. Moreover, some of the molecular mechanisms that link the mentioned association have been clarified. Cancer pathogenesis has been associated with physical mutations and environmental factors, whereas a limited rate has been associated with germline mutations. The special role of environmental factors in cancer pathogenesis has been associated with diverse types of chronic inflammation. It has been recorded that 30% of cancer cases can be attributed to smoking and inhaled pollutants, such as asbestos and carbon dioxide silicon, 20% are associated with chronic infections, and 35% are related to nutrition factors. Common bacterial and viral infections increase the risk of cancer development, however smoking acts as a promoter due to its ability to cause chronic inflammation. Similarly, advanced age and cellular senescence has been recorded to have the same role, as cancer pathogenesis promoters, because act through inflammatory mechanisms. Cellular senescence and damaged DNA accumulation are able to enhance chronic inflammation which promotes tumorigenesis. Inflammation-induced cancer contributes to tumor development through different pathways, such as epigenetic alterations and subsequent inappropriate gene expression, gene instability induction, increased proliferation and resistance to apoptosis of the initial cells, immuno-suppression, induction of tumor angiogenesis, tissue remodeling, and eventually development of metastasis.

The Regulation Pathway of VEGF Gene Expression Is Different between 2D Cells and 3D Spheroids in Human Lung Cancer Cells.

Angiogenesis is involved in the malignant transformation of cancers. Vascular endothelial growth factor (VEGF) is important in inducing angiogenesis. Cultured cells play an important role in analyzing the regulation of VEGF expression, and it is revealed that VEGF expression is induced under hypoxia. However, it has been shown that there are differences in the pathway for gene expression between two-dimensional (2D) cells and in vivo cells. Three-dimensional (3D) spheroids constructed in 3D culture with a gene expression pattern more similar to that of in vivo cells than 2D cells have been used to solve this problem. This study analyzed the VEGF gene expression pathway in 3D spheroids of human lung cancer cells, A549 and H1703. Hypoxia-inducible factor-1α (HIF-1α) and aryl hydrocarbon receptor nuclear translocator (ARNT) regulated VEGF gene expression in 3D spheroids. However, VEGF gene expression was not regulated by HIF-1α in 2D cells. To conclude, we found that the regulatory pathway of VEGF gene expression is different between 2D cells and 3D spheroids in human lung cancer cells. These results suggest the possibility of a new VEGF gene expression regulation pathway in vivo. In addition, they show useful knowledge for the analysis of angiogenesis induction mechanisms and also demonstrate the usefulness of 3D spheroids.

Curcumin and chemokines: mechanism of action and therapeutic potential in inflammatory diseases.

Chemokines belong to the family of cytokines with chemoattractant properties that regulate chemotaxis and leukocyte migration, as well as the induction of angiogenesis and maintenance of hemostasis. Curcumin, the major component of the Curcuma longa rhizome, has various pharmacological actions, including anti-inflammatory, immune-regulatory, anti-oxidative, and lipid-modifying properties. Chemokines and chemokine receptors are influenced/modulated by curcumin. Thus, the current review focuses on the molecular mechanisms associated with curcumin's effects on chemoattractant cytokines, as well as putting into context the many studies that have reported curcumin-mediated regulatory effects on inflammatory conditions in the organs/systems of the body (e.g., the central nervous system, liver, and cardiovascular system). Curcumin's effects on viral and bacterial infections, cancer, and adverse pregnancy outcomes are also reviewed.

Fish antimicrobial peptides: at a glance

Generally, antimicrobial peptides (AMPs) are considered as an important part of innate immunity, due to which they provide the first line of defence against various pathogens. Additionally, they also kill pathogens that show resistance towards many antibiotics. Fishes are regularly challenged by various pathogens which not only affect their health but the risk of becoming resistant to conventional antibiotics is also increasing. As fishes shows more dependence on innate immunity, AMPs can aid as important defensive weapon in fishes. In general, AMPs exhibit various multidimensional characteristics such as neutralization of pathogens (viral, fungal & bacterial), rapidly diffuse to the infection site, and other immune cells recruitment to the infected tissues. AMPs also show various biological effects such as immunomodulation, neutralization of endotoxin and angiogenesis induction. There are numerous AMPs that have been isolated from fishes but not fully characterized at molecular level. In this review we basically focus on approaches used to design new AMP, machine learning approach, current objectives of AMPs and future prospects.

Molecular Regulation of the Response of Brain Pericytes to Hypoxia.

The brain needs sufficient oxygen in order to function normally. This is achieved by a large vascular capillary network ensuring that oxygen supply meets the changing demand of the brain tissue, especially in situations of hypoxia. Brain capillaries are formed by endothelial cells and perivascular pericytes, whereby pericytes in the brain have a particularly high 1:1 ratio to endothelial cells. Pericytes not only have a key location at the blood/brain interface, they also have multiple functions, for example, they maintain blood-brain barrier integrity, play an important role in angiogenesis and have large secretory abilities. This review is specifically focused on both the cellular and the molecular responses of brain pericytes to hypoxia. We discuss the immediate early molecular responses in pericytes, highlighting four transcription factors involved in regulating the majority of transcripts that change between hypoxic and normoxic pericytes and their potential functions. Whilst many hypoxic responses are controlled by hypoxia-inducible factors (HIF), we specifically focus on the role and functional implications of the regulator of G-protein signaling 5 (RGS5) in pericytes, a hypoxia-sensing protein that is regulated independently of HIF. Finally, we describe potential molecular targets of RGS5 in pericytes. These molecular events together contribute to the pericyte response to hypoxia, regulating survival, metabolism, inflammation and induction of angiogenesis.

Bioinformatic Analysis of miR-200b/429 and Hub Gene Network in Cervical Cancer

The miR-200b/429 located at 1p36 is a highly conserved miRNA cluster emerging as a critical regulator of cervical cancer. Using publicly available miRNA expression data from TCGA and GEO followed by independent validation, we aimed to identify the association between miR-200b/429 expression and cervical cancer. miR-200b/429 cluster was significantly overexpressed in cancer samples compared to normal samples. miR-200b/429 expression did not correlate with patient survival; however, its overexpression correlated with histological type. Protein–protein interaction analysis of 90 target genes of miR-200b/429 identified EZH2, FLT1, IGF2, IRS1, JUN, KDR, SOX2, MYB, ZEB1, and TIMP2 as the top ten hub genes. PI3K–AKT and MAPK signaling pathways emerged as major target pathways of miR-200b/429 and their hub genes. Kaplan–Meier survival analysis showed the expression of seven miR-200b/429 target genes (EZH2, FLT1, IGF2, IRS1, JUN, SOX2, and TIMP2) to influence the overall survival of patients. The miR-200a-3p and miR-200b-5p could help predict cervical cancer with metastatic potential. The cancer hallmark enrichment analysis showed hub genes to promote growth, sustained proliferation, resistance to apoptosis, induction of angiogenesis, activation of invasion, and metastasis, enabling replicative immortality, evading immune destruction, and tumor-promoting inflammation. The drug–gene interaction analysis identified 182 potential drugs to interact with 27 target genes of miR-200b/429 with paclitaxel, doxorubicin, dabrafenib, bortezomib, docetaxel, ABT-199, eribulin, vorinostat, etoposide, and mitoxantrone emerging as the top ten best candidate drugs. Taken together, miR-200b/429 and associated hub genes can be helpful for prognostic application and clinical management of cervical cancer.

Revisiting the hallmarks of cancer: A new look at long noncoding RNAs in breast cancer.

Breast cancer is one of the leading causes of death in women worldwide. The increasing understanding of the molecular mechanisms underlying its heterogeneity favors a better understanding of tumor biology and consequently the development of better diagnostic and treatment techniques. The advent of tumor genome sequencing techniques has highlighted more participants in the process, in addition to protein-coding genes. Thus, it is now known that long noncoding RNAs, previously described as transcriptional noise with no biological function, are intimately associated with tumor development. In breast cancer, they are abnormally expressed and closely associated with tumor progression, which makes them attractive diagnostic biomarkers and prognostic and specific therapeutic targets. Therefore, a thorough understanding of the regulatory mechanisms of long noncoding RNAs in breast cancer is essential for the search for new treatment strategies. In this review, we summarize the major long noncoding RNAs and their association with the cancer characteristics of the ability to sustain proliferative signaling, evasion of growth suppressors, replicative immortality, activation of invasion and metastasis, induction of angiogenesis, resistance to cell death, reprogramming of energy metabolism, genomic instability and sustained mutations, promotion of tumor inflammation, and evasion of the immune system. In addition, we report and suggest how they can be used as prognostic biomarkers and possible therapeutic targets.

Self-Assembled DNA Nanocages Promote Cell Migration and Differentiation of Human Umbilical Vein Endothelial Cells.

DNA nanocages have been explored for abilities to influence cellular behavior and functions. Recent times have seen the development of new emergent functionalities of DNA nanodevices as a class of biomaterials with an immense capacity to interface with biological systems and with vast potential in disease diagnosis and therapeutics. Being chemically robust and biocompatible in nature, DNA nanocages have been surface modified and structurally fine-tuned to find emerging applications in the field of stem-cell therapy and tissue regeneration. DNA nanocages can be used for therapeutic angiogenesis that involves the induction of blood vessel formation and can be used to treat ischemic diseases like stroke or heart failure. This work addresses the effect of DNA nanocages' structural topology on their capacity to stimulate endothelial cell angiogenesis. We tested a panel of four DNA nanocage geometries and checked their potential on the differentiation of human umbilical vein endothelial cells (HUVECs). While different DNA nanocage geometries showed successful induction of angiogenesis and cell migration in HUVECs, tetrahedral DNA cages showed the maximum uptake and angiogenesis potential, thus indicating that not only the composition of materials, but also the 3D arrangement of ligands might play role in stimulating angiogenesis.

Evaluation of Cyclin D1 and Human Epidermal Growth Factor Receptor 2 Neu Protein Expression in Head and Neck Squamous Cell Carcinoma.

Background Head and neck cancers are highly aggressive, frequently occurring cancers that are prevalent worldwide. The mainstay of their treatment is surgery, followed by adjuvant therapy. Various studies have documented the usefulness of molecular markers in carcinogenesis and have proven helpful in the diagnosis and treatment of head and neck cancers. Cyclin D1 is a proto‑oncogene, overexpression of which leads to the accelerated entry of cells in the S phase of the cell cycle, causing uncontrolled proliferation of the cells. The dysregulation of human epidermal growth factor receptor 2 (HER2) neu is also related to multiple features of malignancy, including loss of cell cycle control, induction of angiogenesis, and resistance to apoptotic stimuli. This study seeks to identify a subset of patients with a bad prognosis who may require aggressive treatment strategies. Aim This study aims to determine the proportion of the expression of cyclin D1 and HER2 neu in head and neck squamous cell carcinoma (HNSCC) and analyze the association between the expression of cyclin D1 and HER2 neu using histological grading, tumor, node, and metastasis (TNM) staging, and nodal status of the tumor. Furthermore, this study also aims to document clinical outcomes, such as locoregional control, depth of invasion (DOI), and regional metastasis regarding the expression of cyclin D1 and HER2 neu in HNSCC. Setting and design This study is a laboratory-based observational study. Materials and methods Seventy histologically proven cases of HNSCC were studied for various histopathological parameters, and further immunohistochemistry (IHC) was performed for cyclin D1 and HER2 neu. The expression and intensity of cyclin D1 were multiplied, and the total score was derived. The College of American Pathologists/American Society of Clinical Oncology (CAP/ASCO) guidelines for HER2 neu testing in breast cancer were used for scoring. Result Out of 70 cases, 52 (75%) demonstrated strong and moderate positivity for cyclin D1, and the p-values were 0.017, 0.001, and 0.032 for depth of invasion, TNM stage, and lymph node metastases, respectively,for cyclin D1, which was considered statistically significant. For HER2 neu, five out of 70 cases were positive, and the p-value was significant for depth of invasion (0.008). Conclusion The expression of the above marker cyclin D1 increases with stage, DOI, and positive lymph node status. Hence, cyclin D1 immunoexpression can be helpful in the early assessment of HNSCC behavior and can serve as an independent prognostic marker. Furthermore, it was observed that HER2 neu was significant with an increase in depth of invasion of tumor, which, in the American Joint Committee on Cancer (AJCC) eighth edition, is considered an important factor for determining the stage of the tumor. Further research is needed to examine whether HER2 neu can act as a prognostic factor for HNSCC and if it can be targeted for treatment options.

Wound Healing Effect of 20(S)-Protopanaxadiol of Ginseng Involves VEGF-ERK Pathways in HUVECs and Diabetic Mice

Wound healing is the process of skin and soft tissue repair following an injury. Angiogenesis is an essential process in wound healing and plays an important role in tissue regeneration. Ginseng is mainly composed of saponins and protopanaxadiol-based ginsenosides, namely Rb1, Rb2, Rc, Re, Rg1, and Rf. 20(S)-protopanaxadiol (PPD) and 20(S)-protopanaxatriol (PPT) are aglycones of ginsenosides produced by metabolic processes and heat treatment. This study aimed to investigate the wound healing effects of active ingredients of ginseng, namely ginsenosides and aglycones, in various cellular and animal skin wound models. The angiogenic effects of ginsenosides were investigated in human umbilical vein endothelial cells (HUVECs). All experiments were conducted at increased intracellular glucose concentrations and the induction of angiogenesis through tube formation was evaluated. Among the ginsenosides and aglycones used in this study, PPD showed the strongest wound-healing activity. Cell scratch experiments confirmed that PPD increased intracellular proliferation and cell migration at high glucose concentrations, and western blotting of HUVECs showed that phosphorylated ERK, Akt, and p38 were regulated. We observed accelerated wound healing with PPD treatment in STZ-treated mice. Overall, the findings suggested that PPD could possibly help improve skin wound healing in patients with diabetes, although further research is recommended.

Induction of Angiogenesis by Genetically Modified Human Umbilical Cord Blood Mononuclear Cells

Stimulating the process of angiogenesis in treating ischemia-related diseases is an urgent task for modern medicine, which can be achieved through the use of different cell types. Umbilical cord blood (UCB) continues to be one of the attractive cell sources for transplantation. The goal of this study was to investigate the role and therapeutic potential of gene-engineered umbilical cord blood mononuclear cells (UCB-MC) as a forward-looking strategy for the activation of angiogenesis. Adenovirus constructs Ad-VEGF, Ad-FGF2, Ad-SDF1α, and Ad-EGFP were synthesized and used for cell modification. UCB-MCs were isolated from UCB and transduced with adenoviral vectors. As part of our in vitro experiments, we evaluated the efficiency of transfection, the expression of recombinant genes, and the secretome profile. Later, we applied an in vivo Matrigel plug assay to assess engineered UCB-MC's angiogenic potential. We conclude that hUCB-MCs can be efficiently modified simultaneously with several adenoviral vectors. Modified UCB-MCs overexpress recombinant genes and proteins. Genetic modification of cells with recombinant adenoviruses does not affect the profile of secreted pro- and anti-inflammatory cytokines, chemokines, and growth factors, except for an increase in the synthesis of recombinant proteins. hUCB-MCs genetically modified with therapeutic genes induced the formation of new vessels. An increase in the expression of endothelial cells marker (CD31) was revealed, which correlated with the data of visual examination and histological analysis. The present study demonstrates that gene-engineered UCB-MC can be used to stimulate angiogenesis and possibly treat cardiovascular disease and diabetic cardiomyopathy.

The BAP31/miR-181a-5p/RECK axis promotes angiogenesis in colorectal cancer via fibroblast activation.

B-cell receptor-associated protein 31 (BAP31) has been recognized as a tumor-associated protein and has largely been shown to promote metastasis in a variety of cancers. Cancer metastasis arises through multistep pathways, and the induction of angiogenesis is shown to be a rate-limiting step in the process of tumor metastasis. This study explored the effect of BAP31 on colorectal cancer (CRC) angiogenesis by regulating the tumor microenvironment. First, exosomes from BAP31-regulated CRCs affected the transition of normal fibroblasts to proangiogenic cancer-associated fibroblasts (CAFs) in vivo and in vitro. Next, microRNA sequencing was performed to analyze the microRNA expression profile of exosomes secreted from BAP31- overexpressing CRCs. The results indicated that the expression of BAP31 in CRCs significantly altered the levels of exosomal microRNAs, such as miR-181a- 5p. Meanwhile, an in vitro tube formation assay showed that fibroblasts with high levels of miR-181a-5p significantly promoted endothelial cell angiogenesis. Critically, we first identified that miR-181a-5p directly targeted the 3'-untranslated region (3'UTR) of reversion-inducing cysteine-rich protein with kazal motifs (RECK) using the dual-luciferase activity assay, which drove fibroblast transformation into proangiogenic CAFs by upregulating matrix metalloproteinase-9 (MMP-9) and phosphorylation of mothers against decapentaplegic homolog 2/Mothers against decapentaplegic homolog 3 (Smad2/3). Exosomes from BAP31-overexpressing/BAP31-knockdown CRCs are found to manipulate the transition of fibroblasts into proangiogenic CAFs by the miR-181a-5p/RECK axis.

Exosomes for angiogenesis induction in ischemic disorders.

Ischaemic disorders are leading causes of morbidity and mortality worldwide. While the current therapeutic approaches have improved life expectancy and quality of life, they are unable to "cure" ischemic diseases and instate regeneration of damaged tissues. Exosomes are a class of extracellular vesicles with an average size of 100-150 nm, secreted by many cell types and considered a potent factor of cells for paracrine effects. Since exosomes contain multiple bioactive components such as growth factors, molecular intermediates of different intracellular pathways, microRNAs and nucleic acids, they are considered as cell-free therapeutics. Besides, exosomes do not rise cell therapy concerns such as teratoma formation, alloreactivity and thrombotic events. In addition, exosomes are stored and utilized more convenient. Interestingly, exosomes could be an ideal complementary therapeutic tool for ischemic disorders. In this review, we discussed therapeutic functions of exosomes in ischemic disorders including angiogenesis induction through various mechanisms with specific attention to vascular endothelial growth factor pathway. Furthermore, different delivery routes of exosomes and different modification strategies including cell preconditioning, gene modification and bioconjugation, were highlighted. Finally, pre-clinical and clinical investigations in which exosomes were used were discussed.