The tetraspanins CD151 and Tspan8 are essential exosome components for the crosstalk between cancer initiating cells and their surrounding

Tetraspanins in digestive‑system cancers: Expression, function and therapeutic potential (Review)

The tetraspanin family of membrane proteins is essential for controlling different biological processes such as cell migration, penetration, adhesion, growth, apoptosis, angiogenesis and metastasis. The present review summarized the current knowledge regarding the expression and roles of tetraspanins in different types of cancer of the digestive system, including gastric, liver, colorectal, pancreatic, esophageal and oral cancer. Depending on the type and context of cancer, tetraspanins can act as either tumor promoters or suppressors. In the present review, the importance of tetraspanins in serving as biomarkers and targets for different types of digestive system‑related cancer was emphasized. Additionally, the molecular mechanisms underlying the involvement of tetraspanins in cancer progression and metastasis were explored. Furthermore, the current challenges are addressed and future research directions for advancing investigations related to tetraspanins in the context of digestive system malignancies are proposed.

Deciphering extracellular vesicles protein cargo in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) presents a significant therapeutic challenge as it is frequently diagnosed at advanced inoperable stages. Therefore, the development of a reliable screening tool for PDAC is crucial for effective prevention and treatment. Extracellular vesicles (EVs), characterized by their cup-shaped lipid bilayer structure and ubiquitous release from various cell types, offer notable advantages as an emerging liquid biopsy technique that is rapid, minimally invasive, easily sampled, and cost-effective. While EVs play a substantial role in cancer progression, EV proteins serve as direct mediators of diverse cellular behaviors and have immense potential as biomarkers for PDAC diagnosis and prognostication. This review provides an overview of EV proteins regarding PDAC diagnosis and prognostic implications as well as disease progression.

Applications of mesenchymal stem cell-exosome components in wound infection healing: new insights

The healing process at a wound is made up of many types of cells, growth factors, the extracellular matrix, nerves and blood vessels all interacting with each other in complex and changing ways. Microbial colonization and proliferation are possible at the place of injury, which makes infection more likely. Because of this, any cut has a chance of getting an infection. Researchers have found that wound infections make patients more upset and cost the healthcare system a lot of money. Surgical site infections happen a lot to people who have recently had surgery. This study shows that such surgical infection is linked to a high rate of illness and death. This is shown by the fact that 25% of patients get serious sepsis and need to be transferred to an intensive care unit. In both animal models and people, mesenchymal stem cells (MSCs) play an active role in all stages of wound healing and have positive effects. Exosomes are one of the main things MSCs release. They have effects that are similar to those of the parent MSCs. Various effector proteins, messenger RNA and microRNAs can be transported by extracellular vesicles to control the activity of target cells. This has a big impact on the healing process. These results suggest that using MSC-exosomes as a new type of cell-free therapy could be a better and safer option than whole cell therapy. This review is mostly about how to use parts of MSC-exosomes to help wound infections heal.

Oxidative stress-mediated epigenetic remodeling, metastatic progression and cell signaling in cancer

Cancer is a serious public health issue and cases are rising at a high rate around the world. Altered production of reactive oxygen species (ROS) causes oxidative stress (OS) which plays a vital role in cancer development by disrupting signaling pathways and genomic integrity in the cellular microenvironment. In this study, we reviewed the regulation of noncoding RNAs, histone modifications, and DNA methylation which OS is involved in. These mechanisms promote cancer growth, metastasis, and resistance to chemotherapeutic agents. There is significant potential to improve patient outcomes through the development of customized medications and interventions that precisely address the role of OS in the onset and progression of cancer. Redox-modulating drugs, antioxidant-based therapies, and measures to restore regular cellular activity and OS-modulated signaling pathways are some examples of these strategies. One other hypothesis rationalizes the cancer-suppressing effect of OS, which acts as a two-edged condition that warns against the use of antioxidants for cancer treatment and management. The present study was executed to review the impact of OS on epigenetic machinery, the evolution of metastatic cancer, and how OS mediates cellular signaling. Along with, insights into the potential of targeting OS-mediated mechanisms for cancer therapy.

Pancreatic cancer cell- and cancer-associated fibroblast-derived exosomes in disease progression, metastasis, and therapy

Exosomes play a crucial role in the progression and spread of pancreatic cancer, serving not only as promoters of tumor growth and organ-specific metastasis but also as promising biomarkers and targets for treatment. These nano vesicles enhance intercellular communication by transferring bioactive molecules, such as proteins and RNAs, between cells. This process significantly affects cancer cell dynamics, including their proliferation, migration, and invasion, while also contributing to drug resistance. Our review focuses on the crucial interactions between cancer cells and fibroblasts mediated by exosomes within the pancreatic cancer microenvironment. We delve into how exosomes from both cancer-associated fibroblasts and the cancer cells themselves drive tumor progression through various mechanisms, such as epithelial-mesenchymal transition and facilitating metastasis to specific organs like the lungs and liver. The potential of leveraging exosomes for therapeutic interventions is also explored, highlighting the importance of understanding their role in cell communication as a step forward in developing more effective pancreatic cancer treatments.

New insights into the role of tetraspanin 6, 7, and 8 in physiology and pathology

BACKGROUND

The tetraspanin (TSPAN) family comprises 33 membrane receptors involved in various physiological processes in humans. Tetrasapanins are surface proteins expressed in cells of various organisms. They are localised to the cell membrane by four transmembrane domains (TM4SF). These domains bind several cell surface receptors and signalling proteins to tetraspanin-enriched lipid microdomains (TERM or TEM). Tetraspanins play a critical role in anchoring many proteins. They also act as a scaffold for cell signalling proteins.

AIM

To summarise how tetraspanins 6, 7 and 8 contribute to the carcinogenesis process in different types of cancer.

METHODS

To provide a comprehensive review of the role of tetraspanins 6, 7 and 8 in cancer biology, we conducted a thorough search in PubMed, Embase and performed manual search of reference list to collect and extract data.

DISCUSSION

The assembly of tetraspanins covers an area of approximately 100-400 nm. Tetraspanins are involved in various biological processes such as membrane fusion, aggregation, proliferation, adhesion, cell migration and differentiation. They can also regulate integrins, cell surface receptors and signalling molecules. Tetraspanins form direct bonds with proteins and other members of the tetraspanin family, forming a hierarchical network of interactions and are thought to be involved in cell and membrane compartmentalisation. Tetraspanins have been implicated in cancer progression and have been shown to have multiple binding partners and to promote cancer progression and metastasis. Clinical studies have documented a correlation between the level of tetraspanin expression and the prediction of cancer progression, including breast and lung cancer.

CONCLUSIONS

Tetraspanins are understudied in almost all cell types and their functions are not clearly defined. Fortunately, it has been possible to identify the basic mechanisms underlying the biological role of these proteins. Therefore, the purpose of this review is to describe the roles of tetraspanins 6, 7 and 8.

Decoding the secrets of small extracellular vesicle communications: exploring the inhibition of vesicle-associated pathways and interception strategies for cancer treatment

Cancer disease is the second leading cause of death worldwide. In 2023, about 2 million new cancer cases and 609,820 cancer deaths are projected to occur in the United States. The driving forces of cancer progression and metastasis are widely varied and comprise multifactorial events. Although there is significant success in treating cancer, patients still present with tumors at advanced stages. Therefore, the discovery of novel oncologic pathways has been widely developed. Tumor cells communicate with each other through small extracellular vesicles (sEVs), which contribute to tumor-stromal interaction and promote tumor growth and metastasis. sEV-specific inhibitors are being investigated as a next-generation cancer therapy. A literature search was conducted to discuss different options for targeting sEV pathways in cancer cells. However, there are some challenges that need to be addressed in targeting sEVs: i) specificity and toxicity of sEV inhibitor, ii) targeted delivery of sEV inhibitors, iii) combination of sEV inhibitors with current standard chemotherapy to improve patients' clinical outcomes, and iv) data reproducibility and applicability at distinct levels of the disease. Despite these challenges, sEV inhibitors have immense potential for effectively treating cancer patients.

Exosomal non-coding RNA: A new frontier in diagnosing and treating pancreatic cancer: A review

Pancreatic cancer is the most fatal malignancy worldwide. Once diagnosed, most patients are already at an advanced stage because of their highly heterogeneous, drug-resistant, and metastatic nature and the lack of effective diagnostic markers. Recently, the study of proliferation, metastasis, and drug resistance mechanisms in pancreatic cancer and the search for useful diagnostic markers have posed significant challenges to the scientific community. Exosomes carry various biomolecules (DNA, non-coding RNAs (ncRNAs), proteins, and lipids) that mediate communication between tumors and other cells. ncRNAs can be transported through exosomes to numerous relevant receptor cells and regulate local epithelial-mesenchymal transition (EMT) in tumor tissue, proliferation, drug resistance, and the establishment of pre-metastatic ecological niches in distant organs. In summary, exosomal ncRNAs promote tumor cell proliferation, invasion, and metastasis through multiple EMT, immunosuppression, angiogenesis, and extracellular matrix remodeling pathways. Moreover, we discuss the significant therapeutic significance of exosomal ncRNAs as PC biomarkers.

Small extracellular vesicles promote stiffness-mediated metastasis

Tissue stiffness is a critical prognostic factor in breast cancer and is associated with metastatic progression. Here we show an alternative and complementary hypothesis of tumor progression whereby physiological matrix stiffness affects the quantity and protein cargo of small EVs produced by cancer cells, which in turn drive their metastasis. Primary patient breast tissue produces significantly more EVs from stiff tumor tissue than soft tumor adjacent tissue. EVs released by cancer cells on matrices that model human breast tumors (25 kPa; stiff EVs) feature increased adhesion molecule presentation (ITGα 2 β 1 , ITGα 6 β 4 , ITGα 6 β 1 , CD44) compared to EVs from softer normal tissue (0.5 kPa; soft EVs), which facilitates their binding to extracellular matrix (ECM) protein collagen IV, and a 3-fold increase in homing ability to distant organs in mice. In a zebrafish xenograft model, stiff EVs aid cancer cell dissemination through enhanced chemotaxis. Moreover, normal, resident lung fibroblasts treated with stiff and soft EVs change their gene expression profiles to adopt a cancer associated fibroblast (CAF) phenotype. These findings show that EV quantity, cargo, and function depend heavily on the mechanical properties of the extracellular microenvironment.

Unlocking the potential of exosomes in cancer research: A paradigm shift in diagnosis, treatment, and prevention

Exosomes, which are tiny particles released by cells, have the ability to transport various molecules, including proteins, lipids, and genetic material containing non-coding RNAs (ncRNAs). They are associated with processes like cancer metastasis, immunity, and tissue repair. Clinical trials have shown exosomes to be effective in treating cancer, inflammation, and chronic diseases. Mesenchymal stem cells (MSCs) and dendritic cells (DCs) are common sources of exosome production. Exosomes have therapeutic potential due to their ability to deliver cargo, modulate the immune system, and promote tissue regeneration. Bioengineered exosomes could revolutionize disease treatment. However, more research is needed to understand exosomes in tumor growth and develop new therapies. This paper provides an overview of exosome research, focusing on cancer and exosome-based therapies including chemotherapy, radiotherapy, and vaccines. It explores exosomes as a drug delivery system for cancer therapy, highlighting their advantages. The article discusses using exosomes for various therapeutic agents, including drugs, antigens, and RNAs. It also examines challenges with engineered exosomes. Analyzing exosomes for clinical purposes faces limitations in sensitivity, specificity, and purification. On the other hand, Nanotechnology offers solutions to overcome these challenges and unlock exosome potential in healthcare. Overall, the article emphasizes the potential of exosomes for personalized and targeted cancer therapy, while acknowledging the need for further research.

Molecular Regulation and Oncogenic Functions of TSPAN8

Tetraspanins, a superfamily of small integral membrane proteins, are characterized by four transmembrane domains and conserved protein motifs that are configured into a unique molecular topology and structure in the plasma membrane. They act as key organizers of the plasma membrane, orchestrating the formation of specialized microdomains called "tetraspanin-enriched microdomains (TEMs)" or "tetraspanin nanodomains" that are essential for mediating diverse biological processes. TSPAN8 is one of the earliest identified tetraspanin members. It is known to interact with a wide range of molecular partners in different cellular contexts and regulate diverse molecular and cellular events at the plasma membrane, including cell adhesion, migration, invasion, signal transduction, and exosome biogenesis. The functions of cell-surface TSPAN8 are governed by ER targeting, modifications at the Golgi apparatus and dynamic trafficking. Intriguingly, limited evidence shows that TSPAN8 can translocate to the nucleus to act as a transcriptional regulator. The transcription of TSPAN8 is tightly regulated and restricted to defined cell lineages, where it can serve as a molecular marker of stem/progenitor cells in certain normal tissues as well as tumors. Importantly, the oncogenic roles of TSPAN8 in tumor development and cancer metastasis have gained prominence in recent decades. Here, we comprehensively review the current knowledge on the molecular characteristics and regulatory mechanisms defining TSPAN8 functions, and discuss the potential and significance of TSPAN8 as a biomarker and therapeutic target across various epithelial cancers.

A review on the use of extracellular vesicles for the delivery of drugs and biological therapeutics

INTRODUCTION

Exosomes, a type of extracellular vesicles, are effective tools for delivering small-molecule drugs and biological therapeutics into cells and tissues. Surface modifications with targeting ligands ensure precise delivery to specific cells, minimizing accumulation in healthy organs and reducing the side effects. This is a rapidly growing area in drug delivery research and this review aims to comprehensively discuss the recent advances in the field.

AREA COVERED

Recent studies have presented compelling evidence supporting the application of exosomes as efficient delivery vehicles that escape endosome trapping, achieving effective in vivo delivery in animal models. This review provides a systemic discussion on the exosome-based delivery technology, with topics covering exosome purification, surface modification, and targeted delivery of various cargos ranging from siRNAs, miRNAs, and proteins, to small molecule drugs.

EXPERT OPINION

Exosome-based gene and drug delivery has low toxicity and low immunogenicity. Surface modifications of the exosomes can effectively avoid endosome trapping and increase delivery efficiency. This exciting technology can be applied to improve the treatments for a wide variety of diseases.

Cutaneous squamous cell carcinoma-derived extracellular vesicles exert an oncogenic role by activating cancer-associated fibroblasts

Cutaneous squamous cell carcinoma (cSCC) is a fast-increasing cancer with metastatic potential. Extracellular vesicles (EVs) are small membrane-bound vesicles that play important roles in intercellular communication, particularly in the tumor microenvironment (TME). Here we report that cSCC cells secrete an increased number of EVs relative to normal human epidermal keratinocytes (NHEKs) and that interfering with the capacity of cSCC to secrete EVs inhibits tumor growth in vivo in a xenograft model of human cSCC. Transcriptome analysis of tumor xenografts by RNA-sequencing enabling the simultaneous quantification of both the human and the mouse transcripts revealed that impaired EV-production of cSCC cells prominently altered the phenotype of stromal cells, in particular genes related to extracellular matrix (ECM)-formation and epithelial-mesenchymal transition (EMT). In line with these results, co-culturing of human dermal fibroblasts (HDFs) with cSCC cells, but not with normal keratinocytes in vitro resulted in acquisition of cancer-associated fibroblast (CAF) phenotype. Interestingly, EVs derived from metastatic cSCC cells, but not primary cSCCs or NHEKs, were efficient in converting HDFs to CAFs. Multiplex bead-based flow cytometry assay and mass-spectrometry (MS)-based proteomic analyses revealed the heterogenous cargo of cSCC-derived EVs and that especially EVs derived from metastatic cSCCs carry proteins associated with EV-biogenesis, EMT, and cell migration. Mechanistically, EVs from metastatic cSCC cells result in the activation of TGFβ signaling in HDFs. Altogether, our study suggests that cSCC-derived EVs mediate cancer-stroma communication, in particular the conversion of fibroblasts to CAFs, which eventually contribute to cSCC progression.

Exosomal delivery of cannabinoids against cancer

Exosomes are extracellular vesicles (EVs) originating from endosomes that play a role in cellular communication. These vesicles which mimic the parental cells that release them are promising candidates for targeted drug delivery and therapeutic applications against cancer because of their favorable biocompatibility, specific targeting, low toxicity, and immunogenicity. Currently, Delta-9-tetrahydrocannabinol (THC), cannabidiol (CBD) and other cannabinoids (e.g., CBG, THCV, CBC), are being explored for their anticancer and anti-proliferative properties. Several mechanisms, including cell cycle arrest, proliferation inhibition, activation of autophagy and apoptosis, inhibition of adhesion, metastasis, and angiogenesis have been proposed for their anticancer activity. EVs could be engineered as cannabinoid delivery systems for tumor-specificity leading to superior anticancer effects. This review discusses current techniques for EV isolation from various sources, characterization and strategies to load them with cannabinoids. More extensively, we culminate information available on different sources of EVs that have anticancer activity, mechanism of action of cannabinoids against various wild type and resistant tumors and role of CBD in histone modifications and cancer epigenetics. We have also enumerated the role of EVs containing cannabinoids against various tumors and in chemotherapy induced neuropathic pain.

Exploring the role of CD151 in the tumor immune microenvironment: Therapeutic and clinical perspectives

CD151 is a transmembrane protein implicated in tumor progression and has been shown to regulate various cellular and molecular mechanisms contributing to malignancy. More recently, the role of CD151 in the tumor immune microenvironment (TIME) has gained attention as a potential target for cancer therapy. This review aims to explore the role of CD151 in the TIME, focusing on the therapeutic and clinical perspectives. The role of CD151 in regulating the interactions between tumor cells and the immune system will be discussed, along with the current understanding of the molecular mechanisms underlying these interactions. The current state of the development of CD151-targeted therapies and the potential clinical applications of these therapies will also be reviewed. This review provides an overview of the current knowledge on the role of CD151 in the TIME and highlights the potential of CD151 as a therapeutic target for cancer treatment.

A comprehensive survey into the role of exosomes in pancreatic cancer; from the origin of cancer to the progress and possibility of diagnosis and treatment

Pancreatic cancer is the fourth most common malignant tumor in the world, which has a high mortality rate due to high invasiveness, early metastases, lack of specific symptoms, and high invasiveness. Recent studies have shown that exosomes can be essential sources of biomarkers in pancreatic cancer. Over the past ten years, exosomes have been implicated in multiple trials to prevent the growth and metastasis of many cancers, including pancreatic cancer. Exosomes also play essential roles in immune evasion, invasion, metastasis, proliferation, apoptosis, drug resistance, and cancer stemness. Exosomes help cells communicate by carrying proteins and genetic material, such as non-coding RNAs, including mRNAs and microRNAs. This review examines the biological significance of exosomes in pancreatic cancer and their functions in tumor invasion, metastasis, treatment resistance, proliferation, stemness, and immune evasion. We also emphasize recent advances in our understanding of the main functions of exosomes in diagnosing and treating pancreatic cancer.

The versatile roles of testrapanins in cancer from intracellular signaling to cell-cell communication: cell membrane proteins without ligands

The tetraspanins (TSPANs) are a family of four-transmembrane proteins with 33 members in mammals. They are variably expressed on the cell surface, various intracellular organelles and vesicles in nearly all cell types. Different from the majority of cell membrane proteins, TSPANs do not have natural ligands. TSPANs typically organize laterally with other membrane proteins to form tetraspanin-enriched microdomains (TEMs) to influence cell adhesion, migration, invasion, survival and induce downstream signaling. Emerging evidence shows that TSPANs can regulate not only cancer cell growth, metastasis, stemness, drug resistance, but also biogenesis of extracellular vesicles (exosomes and migrasomes), and immunomicroenvironment. This review summarizes recent studies that have shown the versatile function of TSPANs in cancer development and progression, or the molecular mechanism of TSPANs. These findings support the potential of TSPANs as novel therapeutic targets against cancer.

Proteomic profiling and ROC analysis identify CD151 and ELAVL1 as potential therapy response markers for the antiviral drug in resistant TNBC

Triple-negative breast cancer is high heterogeneous, aggressive, and metastatic with poor prognosis. Despite of advances in targeted therapies, TNBC has been reported to cause high morbidity and mortality. A rare subpopulation within the tumor microenvironment organized into a hierarchy of cancer stem cells is responsible for therapy resistance and tumor recurrence. Repurposing of antiviral drugs for cancer treatment is gaining momentum due to reduced cost, labour, and research time, but limited due to lack of prognostic, and predictive markers. The present study investigates proteomic profiling and ROC analysis to identify CD151 and ELAVL1 as potential therapy response markers for the antiviral drug 2-thio-6-azauridine (TAU) in resistant TNBC. The stemness of MDA-MB 231 and MDA-MD 468 adherent cells was enriched by culturing them under non-adherent and non-differentiation conditions. Then, CD151⁺ subpopulation was isolated and characterized for the enrichment of stemness. This study found that CD151 has overexpressed in stemness enriched subpopulations, and also showed CD44 high and CD24 low expression along with stem cell-related transcription factors octamer-binding transcription factor 4 (OCT4) and Sex determining Y-box 2 (SOX2). This study also found that TAU induced significant cytotoxicity and genotoxicity in the CD151⁺TNBC subpopulation and inhibited their proliferation by inducing DNA damage, cell cycle arrest at the G₂M phase, and apoptosis. Further, a proteomic profiling study showed that the expression of CD151 along with ELAVL1, an RNA-binding protein, was significantly reduced with TAU treatment. KM plotter showed correlation of CD151 and ELAVL1 gene expression with a poor prognosis of TNBC. ROC analysis predicted and validated CD151 and ELAVL1 as best therapy response marker for TAU in TNBC. These findings provide new insight into repurposing antiviral drug TAU for treatment of metastatic and drug resistant TNBC.

Pancreatic cancer, stroma, and exosomes

In the pathogenesis of pancreatic adenocarcinoma, tumor stroma plays a key role in both aggressiveness, immune evasion, resistance to chemotherapy, and the ability to metastasize. Among the elements that characterize the behavior of the stroma, extracellular vesicles and, in particular, exosomes play an important role. These extracellular vesicles carry a wide range of bioactive molecules, from transcription factors to microRNAs, which can substantially alter the phenotype of the cellular components of the stroma. Exosomes are involved in the exchange of signals between tumor cells, tumor-associated macrophages, cancer-associated fibroblasts, and also with the healthy cells surrounding the tumor. They can transfer resistance to chemotherapeutic drugs, promote the epithelial-mesenchymal transition, modify the phenotype of macrophages, or induce the expression of molecules that alter the extracellular matrix to facilitate migration and metastasis. On the other hand, all these characteristics make these vesicles first-rate therapeutic targets, as controlling their functionality could greatly enhance the effectiveness of treatments that, today, are still far from be satisfactory.

Diagnostic and Prognostic Role of Extracellular Vesicles in Pancreatic Cancer: Current Evidence and Future Perspectives

Pancreatic cancer is one of the most aggressive tumors, with a dismal prognosis due to poor detection rates at early stages, rapid progression, post-surgical complications, and limited effectiveness of conventional oncologic therapies. There are no consistently reliable biomarkers or imaging modalities to accurately diagnose, classify, and predict the biological behavior of this tumor. Therefore, it is imperative to develop new and improved strategies to detect pancreatic lesions in the early stages of cancerization with greater sensitivity and specificity. Extracellular vesicles, including exosome and microvesicles, are membrane-coated cellular products that are released in the outer environment. All cells produce extracellular vesicles; however, this process is enhanced by inflammation and tumorigenesis. Based on accumulating evidence, extracellular vesicles play a crucial role in pancreatic cancer progression and chemoresistance. Moreover, they may represent potential biomarkers and promising therapy targets. The aim of the present review is to review the current evidence on the role of extracellular vesicles in pancreatic cancer.

Role of exosomes in tumour growth, chemoresistance and immunity: state-of-the-art

Cancer is one of the most lethal diseases, and limited available treatment options contribute to its high mortality rate. Exosomes are considered membrane-bound nanovesicles that include different molecules such as lipids, proteins, and nucleic acids. Virtually most cells could release exosomes via exocytosis in physiological and pathological conditions. Tumour-derived exosomes (TDEs) play essential roles in tumorigenesis, proliferation, progression, metastasis, immune escape, and chemoresistance by transferring functional biological cargos, triggering different autocrine, and paracrine signalling cascades. Due to their antigen-presenting properties, exosomes are widely used as biomarkers and drug carriers and have a prominent role in cancer immunotherapy. They offer various advantages in carrier systems (e.g. in chemotherapy, siRNA, and miRNA), delivery of diagnostic agents owing to their stability, loading of hydrophobic and hydrophilic agents, and drug targeting. Novel exosomes-based carriers can be generated as intelligent systems using various sources and crosslinking chemistry extracellular vesicles (EVs). Exosomes studded with targeting ligands, including peptides, can impart in targeted delivery of cargos to tumour cells. In this review, we comprehensively summarised the important role of tumour-derived exosomes in dictating cancer pathogenesis and resistance to therapy. We have therefore, investigated in further detail the pivotal role of tumour-derived exosomes in targeting various cancer cells and their applications, and prospects in cancer therapy and diagnosis. Additionally, we have implicated the potential utility and significance of tumour exosomes-based nanoparticles as an efficient and novel therapeutic carrier and their applications in treating advanced cancers.

Novel antigens for targeted radioimmunotherapy in hepatocellular carcinoma

Liver cancer is the sixth common cancer and forth cause of cancer-related death worldwide. Based on usually advanced stages of hepatocellular carcinoma (HCC) at the time of diagnosis, therapeutic options are limited and, in many cases, not effective, and typically result in the tumor recurrence with a poor prognosis. Radioimmunotherapy (RIT) offers a selective internal radiation therapy approach using beta or alpha emitting radionuclides conjugated with tumor-specific monoclonal antibodies (mAbs), or specific selective peptides. When compared to chemotherapy or radiotherapy, radiolabeled mAbs against cancer-associated antigens could provide a high therapeutic and exclusive radiation dose for cancerous cells while decreasing the exposure-induced side effects to healthy tissues. The recent advances in cancer immunotherapy, such as blockade of immune-checkpoint inhibitors (ICIs), has changed the landscape of cancer therapy, and the efficacy of different classes of immunotherapy has been tested in many clinical trials. Taking into account the use of ICIs in the liver tumor microenvironment, combined therapies with different approaches may enhance the outcome in the future clinical studies. With the development of novel immunotherapy treatment options in the recent years, there has been a great deal of information about combining the diverse treatment modalities to boost the effectiveness of immunomodulatory drugs. In this opinion review, we will discuss the recent advancements in RIT. The current status of immunotherapy and internal radiotherapy will be updated, and we will propose novel approaches for the combination of both techniques. Potential target antigens for radioimmunotherapy in Hepatocellular carcinoma (HCC). HCC radioimmunotherapy target antigens are the most specific and commonly accessible antigens on the surface of HCC cells. CTLA-4 ligand and receptor, TAMs, PD-1/PD-L, TIM-3, specific IEXs/TEXs, ROBO1, and cluster of differentiation antigens CD105, CD147 could all be used in HCC radioimmunotherapy. Abbreviations: TAMs, tumor-associated macrophages; CTLA-4, cytotoxic T-lymphocyte associated antigen-4; PD-1, Programmed cell death protein 1; PD-L, programmed death-ligand1; TIM-3, T-cell immunoglobulin (Ig) and mucin-domain containing protein-3; IEXs, immune cell-derived exosomes; TEXs, tumor-derived exosomes.

Fluorescence Spectroscopic Analysis of Lateral and Transbilayer Fluidity of Exosome Membranes

Exosomes are small extracellular vesicles (sEVs) involved in distal cell-cell communication and cancer migration by transferring functional cargo molecules. Membrane domains similar to lipid rafts are assumed to occur in exosome membranes and are involved in interactions with target cells. However, the bilayer membrane properties of these small vesicles have not been fully investigated. Therefore, we examined the fluidity, lateral domain separation, and transbilayer asymmetry of exosome membranes using fluorescence spectroscopy. Although there were some differences between the exosomes, TMA-DPH anisotropy showing moderate lipid chain order indicated that ordered phases comprised a significant proportion of exosome membranes. Selective TEMPO quenching of the TMA-DPH fluorescence in the liquid-disordered phase indicated that 40-50% of the exosome membrane area belonged to the ordered phase based on a phase-separated model. Furthermore, NBD-PC in the outer leaflet showed longer fluorescence lifetimes than those in the inner leaflets. Therefore, the exosome membranes maintained transbilayer asymmetry with a topology similar to that of the plasma membranes. In addition, the lateral and transbilayer orders of exosome membranes obtained from different cell lines varied, probably depending on the different membrane lipid components and compositions partially derived from donor cells. As these higher membrane orders and asymmetric topologies are similar to those of cell membranes with lipid rafts, raft-like functional domains are possibly enriched on exosome membranes. These domains likely play key roles in the biological functions and cellular uptake of exosomes by facilitating selective membrane interactions with target organs.

Perineural Invasion in Pancreatic Ductal Adenocarcinoma: From Molecules towards Drugs of Clinical Relevance

Pancreatic ductal adenocarcinoma is one of the most threatening solid malignancies. Molecular and cellular mediators that activate paracrine signalling also regulate the dynamic interaction between pancreatic cancer cells and nerves. This reciprocal interface leads to perineural invasion (PNI), defined as the ability of cancer cells to invade nerves, similar to vascular and lymphatic metastatic cascade. Targeting PNI in pancreatic cancer might help ameliorate prognosis and pain relief. In this review, the modern knowledge of PNI in pancreatic cancer has been analysed and critically presented. We focused on molecular pathways promoting cancer progression, with particular emphasis on neuropathic pain generation, and we reviewed the current knowledge of pharmacological inhibitors of the PNI axis. PNI represents a common hallmark of PDAC and correlates with recurrence, poor prognosis and pain in pancreatic cancer patients. The interaction among pancreatic cancer cells, immune cells and nerves is biologically relevant in each stage of the disease and stimulates great interest, but the real impact of the administration of novel agents in clinical practice is limited. It is still early days for PNI-targeted treatments, and further advanced studies are needed to understand whether they could be effective tools in the clinical setting.

Tumor-derived extracellular vesicles modulate innate immune responses to affect tumor progression

Immune cells are capable of influencing tumor progression in the tumor microenvironment (TME). Meanwhile, one mechanism by which tumor modulate immune cells function is through extracellular vesicles (EVs), which are cell-derived extracellular membrane vesicles. EVs can act as mediators of intercellular communication and can deliver nucleic acids, proteins, lipids, and other signaling molecules between cells. In recent years, studies have found that EVs play a crucial role in the communication between tumor cells and immune cells. Innate immunity is the first-line response of the immune system against tumor progression. Therefore, tumor cell-derived EVs (TDEVs) which modulate the functional change of innate immune cells serve important functions in the context of tumor progression. Emerging evidence has shown that TDEVs dually enhance or suppress innate immunity through various pathways. This review aims to summarize the influence of TDEVs on macrophages, dendritic cells, neutrophils, and natural killer cells. We also summarize their further effects on the progression of tumors, which may provide new ideas for developing novel tumor therapies targeting EVs.

Tetraspanin 8 Subfamily Members Regulate Substrate-Specificity of a Disintegrin and Metalloprotease 17

Ectodomain shedding is an irreversible process to regulate inter- and intracellular signaling. Members of the a disintegrin and metalloprotease (ADAM) family are major mediators of ectodomain shedding. ADAM17 is involved in the processing of multiple substrates including tumor necrosis factor (TNF) α and EGF receptor ligands. Substrates of ADAM17 are selectively processed depending on stimulus and cellular context. However, it still remains largely elusive how substrate selectivity of ADAM17 is regulated. Tetraspanins (Tspan) are multi-membrane-passing proteins that are involved in the organization of plasma membrane micro-domains and diverse biological processes. Closely related members of the Tspan8 subfamily, including CD9, CD81 and Tspan8, are associated with cancer and metastasis. Here, we show that Tspan8 subfamily members use different strategies to regulate ADAM17 substrate selectivity. We demonstrate that in particular Tspan8 associates with both ADAM17 and TNF α and promotes ADAM17-mediated TNF α release through recruitment of ADAM17 into Tspan-enriched micro-domains. Yet, processing of other ADAM17 substrates is not altered by Tspan8. We, therefore, propose that Tspan8 contributes to tumorigenesis through enhanced ADAM17-mediated TNF α release and a resulting increase in tissue inflammation.

The Exosome Journey: From Biogenesis to Regulation and Function in Cancers

Exosomes are a type of small endosomal-derived vesicles ranging from 30 to 150 nm, which can serve as functional mediators in cell-to-cell communication and various physiological and pathological processes. In recent years, exosomes have emerged as crucial mediators of intracellular communication among tumor cells, immune cells, and stromal cells, which can shuttle bioactive molecules, such as proteins, lipids, RNA, and DNA. Exosomes exhibit the high bioavailability, biological stability, targeting specificity, low toxicity, and immune characteristics, suggesting their potentials in the diagnosis and treatment of cancers. They can be applied as an effective tool in the diagnostics, therapeutics, and drug delivery in cancers. This review summarizes the regulation and functions of exosomes in various cancers to augment our understanding of exosomes, which paves the way for parallel advancements in the therapeutic approach of cancers. In this review, we also discuss the challenges and prospects for clinical application of exosome-based diagnostics and therapeutics for cancers.

Potentiality of Exosomal Proteins as Novel Cancer Biomarkers for Liquid Biopsy

Liquid biopsy has been rapidly developed in recent years due to its advantages of non-invasiveness and real-time sampling in cancer prognosis and diagnosis. Exosomes are nanosized extracellular vesicles secreted by all types of cells and abundantly distributed in all types of body fluid, carrying diverse cargos including proteins, DNA, and RNA, which transmit regulatory signals to recipient cells. Among the cargos, exosomal proteins have always been used as immunoaffinity binding targets for exosome isolation. Increasing evidence about the function of tumor-derived exosomes and their proteins is found to be massively associated with tumor initiation, progression, and metastasis in recent years. Therefore, exosomal proteins and some nucleic acids, such as miRNA, can be used not only as targets for exosome isolation but also as potential diagnostic markers in cancer research, especially for liquid biopsy. This review will discuss the existing protein-based methods for exosome isolation and characterization that are more appropriate for clinical use based on current knowledge of the exosomal biogenesis and function. Additionally, the recent studies for the use of exosomal proteins as cancer biomarkers are also discussed and summarized, which might contribute to the development of exosomal proteins as novel diagnostic tools for liquid biopsy.

Exosome-mediated remodeling of the tumor microenvironment: From local to distant intercellular communication

Extracellular vesicles (EVs) are membrane-enveloped nanoscale particles that carry various bioactive signaling molecules secreted by cells. Their biological roles depend on the original cell type from which they are derived and their inclusions. Exosomes, a class of EVs, are released by almost all eukaryotic cell types, including tumor cells. Tumor cell-derived exosomes mediate signal transduction between tumor cells and surrounding non-tumor cells. This intercellular communication actively contributes to the remodeling of the tumor microenvironment (TME) to enable tumor growth, invasion, and metastasis. This review summarizes the latest progress in the exploration of exosome-mediated cell-cell communication implicated in TME remodeling and underlying mechanisms. We focus on the role of cell-cell interactions mediated by tumor cell-derived exosomes in promoting invasion and metastasis, and their potential as a therapeutic intervention target against distant metastasis. We also discuss the clinical translational significance of tumor-derived exosomes for early diagnosis, efficacy and progression evaluations.

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.

Insight into Extracellular Vesicle-Cell Communication: From Cell Recognition to Intracellular Fate

Extracellular vesicles (EVs) are heterogamous lipid bilayer-enclosed membranous structures secreted by cells. They are comprised of apoptotic bodies, microvesicles, and exosomes, and carry a range of nucleic acids and proteins that are necessary for cell-to-cell communication via interaction on the cells surface. They initiate intracellular signaling pathways or the transference of cargo molecules, which elicit pleiotropic responses in recipient cells in physiological processes, as well as pathological processes, such as cancer. It is therefore important to understand the molecular means by which EVs are taken up into cells. Accordingly, this review summarizes the underlying mechanisms involved in EV targeting and uptake. The primary method of entry by EVs appears to be endocytosis, where clathrin-mediated, caveolae-dependent, macropinocytotic, phagocytotic, and lipid raft-mediated uptake have been variously described as being prevalent. EV uptake mechanisms may depend on proteins and lipids found on the surfaces of both vesicles and target cells. As EVs have been shown to contribute to cancer growth and progression, further exploration and targeting of the gateways utilized by EVs to internalize into tumor cells may assist in the prevention or deceleration of cancer pathogenesis.

Tumor-Derived Exosomes Modulate Primary Site Tumor Metastasis

Tumor-derived exosomes (TDEs) are actively produced and released by tumor cells and carry messages from tumor cells to healthy cells or abnormal cells, and they participate in tumor metastasis. In this review, we explore the underlying mechanism of action of TDEs in tumor metastasis. TDEs transport tumor-derived proteins and non-coding RNA to tumor cells and promote migration. Transport to normal cells, such as vascular endothelial cells and immune cells, promotes angiogenesis, inhibits immune cell activation, and improves chances of tumor implantation. Thus, TDEs contribute to tumor metastasis. We summarize the function of TDEs and their components in tumor metastasis and illuminate shortcomings for advancing research on TDEs in tumor metastasis.

Liposomes and Extracellular Vesicles as Drug Delivery Systems: A Comparison of Composition, Pharmacokinetics, and Functionalization

Over the past decades, lipid-based nanoparticle drug delivery systems (DDS) have caught the attention of researchers worldwide, encouraging the field to rapidly develop improved ways for effective drug delivery. One of the most prominent examples is liposomes, which are spherical shaped artificial vesicles composed of lipid bilayers and able to encapsulate both hydrophilic and hydrophobic materials. At the same time, biological nanoparticles naturally secreted by cells, called extracellular vesicles (EVs), have emerged as promising more complex biocompatible DDS. In this review paper, the differences and similarities in the composition of both vesicles are evaluated, and critical mediators that affect their pharmacokinetics are elucidate. Different strategies that have been assessed to tweak the pharmacokinetics of both liposomes and EVs are explored, detailing the effects on circulation time, targeting capacity, and cytoplasmic delivery of therapeutic cargo. Finally, whether a hybrid system, consisting of a combination of only the critical constituents of both vesicles, could offer the best of both worlds is discussed. Through these topics, novel leads for further research are provided and, more importantly, gain insight in what the liposome field and the EV field can learn from each other.

Small extracellular vesicles: from mediating cancer cell metastasis to therapeutic value in pancreatic cancer

Pancreatic cancer is a highly malignant tumor and, is extremely difficult to diagnose and treat. Metastasis is one of the critical steps in the development of cancer and uses cell to cell communication to mediate changes in the microenvironment. Small extracellular vesicles (sEVs)-carry proteins, nucleic acids and other bioactive substances, and are important medium for communication between cells. There are two primary steps in sVEs-mediated metastasis: communication between pancreatic cancer cells and their surrounding microenvironment; and the communication between primary tumor cells and distant organ cells in distant organs that promotes angiogenesis, reshaping extracellular matrix, forming immunosuppressive environment and other ways to form appropriate pre-metastasis niche. Here, we explore the mechanism of localization and metastasis of pancreatic cancer and use sEVs as early biomarkers for the detection and treatment of pancreatic cancer. Video Abstract.

Exogenous and Endogenous Dendritic Cell-Derived Exosomes: Lessons Learned for Immunotherapy and Disease Pathogenesis

Immune therapeutic exosomes, derived exogenously from dendritic cells (DCs), the 'directors' of the immune response, are receiving favorable safety and tolerance profiles in phase I and II clinical trials for a growing number of inflammatory and neoplastic diseases. DC-derived exosomes (EXO), the focus of this review, can be custom tailored with immunoregulatory or immunostimulatory molecules for specific immune cell targeting. Moreover, the relative stability, small size and rapid uptake of EXO by recipient immune cells offer intriguing options for therapeutic purposes. This necessitates an in-depth understanding of mechanisms of EXO biogenesis, uptake and routing by recipient immune cells, as well as their in vivo biodistribution. Against this backdrop is recognition of endogenous exosomes, secreted by all cells, the molecular content of which is reflective of the metabolic state of these cells. In this regard, exosome biogenesis and secretion is regulated by cell stressors of chronic inflammation and tumorigenesis, including dysbiotic microbes, reactive oxygen species and DNA damage. Such cell stressors can promote premature senescence in young cells through the senescence associated secretory phenotype (SASP). Pathological exosomes of the SASP amplify inflammatory signaling in stressed cells in an autocrine fashion or promote inflammatory signaling to normal neighboring cells in paracrine, without the requirement of cell-to-cell contact. In summary, we review relevant lessons learned from the use of exogenous DC exosomes for immune therapy, as well as the pathogenic potential of endogenous DC exosomes.

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.

Tumor extracellular vesicles drive metastasis (it's a long way from home)

Among a plethora of functions, extracellular vesicles released by primary tumors spread in the organism and reach distant organs where they can induce the formation of a premetastatic niche. This constitutes a favorable microenvironment for circulating tumor cells which facilitates their seeding and colonization. In this review, we describe the journey of extracellular vesicles (EVs) from the primary tumor to the future metastatic organ, with a focus on the mechanisms used by EVs to target organs with a specific tropism (i.e., organotropism). We then highlight important tumor EV cargos in the context of premetastatic niche formation and summarize their known effects on extracellular matrix remodeling, angiogenesis, vessel permeabilization, resident cell activation, recruitment of foreign cells, and ultimately the formation of a pro-inflammatory and immuno-tolerant microenvironment. Finally, we discuss current experimental limitations and remaining opened questions in light of metastatic diagnosis and potential therapies targeting PMN formation.

High TSPAN8 expression in epithelial cancer cell-derived small extracellular vesicles promote confined diffusion and pronounced uptake

Small extracellular vesicles (sEVs) play a key role in intercellular communication. Cargo molecules carried by sEVs may affect the phenotype and function of recipient cells. Epithelial cancer cell-derived sEVs, particularly those enriched in CD151 or tetraspanin8 (TSPAN8) and associated integrins, promote tumour progression. The mechanism of binding and modulation of sEVs to recipient cells remains elusive. Here, we used genetically engineered breast cancer cells to derive TSPAN8-enriched sEVs and evaluated the impact of TSPAN8 on target cell membrane's diffusion and transport properties. The single-particle tracking technique showed that TSPAN8 significantly promoted sEV binding via confined diffusion. Functional assays indicated that the transgenic TSPAN8-sEV cargo increased cancer cell motility and epithelial-mesenchymal transition (EMT). In vivo, transgenic TSPAN8-sEV promoted uptake of sEVs in the liver, lung, and spleen. We concluded that TSPAN8 encourages the sEV-target cell interaction via forced confined diffusion and significantly increases cell motility. Therefore, TSPAN8-sEV may serve as an important direct or indirect therapeutic target.

Extracellular vesicles in pancreatic cancer progression and therapies

Pancreatic cancer (PC) is one of the leading causes of cancer-related death worldwide due to delayed diagnosis and limited treatments. More than 90% of all pancreatic cancers are pancreatic ductal adenocarcinoma (PDAC). Extensive communication between tumour cells and other cell types in the tumour microenvironment have been identified which regulate cancer hallmarks during pancreatic tumorigenesis via secretory factors and extracellular vesicles (EVs). The EV-capsuled factors not only facilitate tumour growth locally, but also enter circulation and reach distant organs to construct a pre-metastatic niche. In this review, we delineate the key factors in pancreatic ductal adenocarcinoma derived EVs that mediate different tumour processes. Also, we highlight the factors that are related to the crosstalk with cancer stem cells/cancer-initiating cells (CSC/CIC), the subpopulation of cancer cells that can efficiently metastasize and resist currently used chemotherapies. Lastly, we discuss the potential of EV-capsuled factors in early diagnosis and antitumour therapeutic strategies.

Pancreatic Cancer Small Extracellular Vesicles (Exosomes): A Tale of Short- and Long-Distance Communication

Simple Summary

Even today, pancreatic cancer still has a dismal prognosis. It is characterized by a lack of early symptoms and thus late diagnosis as well as early metastasis. The majority of patients suffer from pancreatic ductal adenocarcinoma (PDAC). PDACs communicate extensively with cellular components of their microenvironment, but also with distant metastatic niches to facilitate tumor progression and dissemination. This crosstalk is substantially enabled by small extracellular vesicles (sEVs, exosomes) with a size of 30–150 nm that are released from the tumor cells. sEVs carry bioactive cargos that reprogram target cells to promote tumor growth, migration, metastasis, immune evasion, or chemotherapy resistance. Interestingly, sEVs also carry novel diagnostic, prognostic and potentially also predictive biomarkers. Moreover, engineered sEVs may be utilized as therapeutic agents, improving treatment options. The role of sEVs for PDAC development, progression, diagnosis, prognosis, and treatment is the focus of this review.

Abstract

Even with all recent advances in cancer therapy, pancreatic cancer still has a dismal 5-year survival rate of less than 7%. The most prevalent tumor subtype is pancreatic ductal adenocarcinoma (PDAC). PDACs display an extensive crosstalk with their tumor microenvironment (TME), e.g., pancreatic stellate cells, but also immune cells to regulate tumor growth, immune evasion, and metastasis. In addition to crosstalk in the local TME, PDACs were shown to induce the formation of pre-metastatic niches in different organs. Recent advances have attributed many of these interactions to intercellular communication by small extracellular vesicles (sEVs, exosomes). These nanovesicles are derived of endo-lysosomal structures (multivesicular bodies) with a size range of 30–150 nm. sEVs carry various bioactive cargos, such as proteins, lipids, DNA, mRNA, or miRNAs and act in an autocrine or paracrine fashion to educate recipient cells. In addition to tumor formation, progression, and metastasis, sEVs were described as potent biomarker platforms for diagnosis and prognosis of PDAC. Advances in sEV engineering have further indicated that sEVs might once be used as effective drug carriers. Thus, extensive sEV-based communication and applications as platform for biomarker analysis or vehicles for treatment suggest a major impact of sEVs in future PDAC research.

Understanding extracellular vesicle and nanoparticle heterogeneity: Novel methods and considerations

Extracellular vesicles (EVs) are a heterogeneous population of membrane-enclosed nanoparticles released by cells. They play a role in intercellular communication and are involved in numerous physiological and pathological processes. Cells release subpopulations of EVs with distinct composition and inherent biological function which overlap in size. Current size-based isolation methods are, therefore, not optimal to discriminate between functional EV subpopulations. In addition, EVs overlap in size with several other biological nanoparticles, such as lipoproteins and viruses. Proteomic analysis has allowed for more detailed study of EV composition, and EV isolation approaches based on this could provide a promising alternative for purification based on size. Elucidating EV heterogeneity and the characteristics and role of EV subpopulations will advance our understanding of EV biology and the role of EVs in health and disease. Here, we discuss current knowledge of EV composition, EV heterogeneity and advances in affinity based EV isolation tools.

SOX9 is a critical regulator of TSPAN8-mediated metastasis in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is the deadliest cancer mainly owing to its proclivity to early metastasis and the lack of effective targeted therapeutic drugs. Hence, understanding the molecular mechanisms underlying early invasion and metastasis by PDAC is imperative for improving patient outcomes. The present study identified that upregulation of TSPAN8 expression in PDAC facilitates metastasis in vivo and in vitro. We found SOX9 as a key transcriptional regulator of TSPAN8 expression in response to EGF stimulation. SOX9 modulation was sufficient to positively regulate endogenous expression of TSPAN8, with concomitant in vitro phenotypic changes such as loss of cell-matrix adherence and increased invasion. Moreover, increased SOX9 and TSPAN8 levels were shown to correlate in human pancreatic cancer specimens and downregulated in vitro by EGFR tyrosine kinase inhibitors. High expression of SOX9 and TSPAN8 has been associated with tumor stage, poor prognosis and poor patient survival in PDAC. In conclusion, this study highlights the importance of the EGF-SOX9-TSPAN8 signaling cascade in the control of PDAC invasion and implies that TSPAN8 may be a promising novel therapeutic target for the treatment of PDAC.

CD151 enrichment in exosomes of luminal androgen receptor breast cancer cell line contributes to cell invasion

Breast cancer is the most common and highly heterogeneous disease in women worldwide. Given the challenges in the treatment of advanced metastatic breast cancer, it is necessary to understand the molecular mechanisms related to disease progression. Exosomes play various roles in the progression of tumors, including promoting the invasion and advancing the distant metastasis. To study the molecular mechanisms related to the progression of luminal androgen receptor (LAR) breast cancer, we first isolated exosomes of MDA-MB-453 cells, a representative cell line of LAR. Through quantitative proteomic analysis, we identified 180 proteins specifically enriched in exosomes after comparing with those in cells, microvesicles, and the 150K supernatant. Among these, CD151, a protein involved in the regulation of cell motility was the most enriched one. CD151-knockdown exosomes reduced the invasion ability of the recipient breast cancer cell and lowered the phosphorylation level of tyrosine-protein kinase Lck, indicating that the invasion of LAR breast cancer may be due to CD151-enriched exosomes. Our work reports for the first time that CD151 was highly abundant in the exosomes of MDA-MB-453 cells and expands the understanding of the development process of LAR subtype, suggesting CD151 may be a potential candidate for the treatment of LAR breast cancer.

The Cellular and Biological Impact of Extracellular Vesicles in Pancreatic Cancer

Simple Summary

The increased incidence and global failure of ongoing therapies project pancreatic cancer as the second deadliest cancer worldwide. While our knowledge of pancreatic cancer cells’ abilities and specificities has drastically improved based on multi-scaled omics, one must consider that much more remains to be uncovered on the role and impact of stromal cells and the established network of communication with tumor cells. This review article discusses how tumor cells communicate with the various cells composing the stroma and its implication in tumor cells’ abilities, PDA (pancreatic ductal adenocarcinoma) carcinogenesis and therapeutic response. We will focus on extracellular vesicles-mediated crosstalk and how this multifaceted dialogue impacts both cellular compartments and its subsequent impact on PDA biology.

Abstract

Deciphering the interactions between tumor and stromal cells is a growing field of research to improve pancreatic cancer-associated therapies and patients’ care. Indeed, while accounting for 50 to 90% of the tumor mass, many pieces of evidence reported that beyond their structural role, the non-tumoral cells composing the intra-tumoral microenvironment influence tumor cells’ proliferation, metabolism, cell death and resistance to therapies, among others. Simultaneously, tumor cells can influence non-tumoral neighboring or distant cells in order to shape a tumor-supportive and immunosuppressive environment as well as influencing the formation of metastatic niches. Among intercellular modes of communication, extracellular vesicles can simultaneously transfer the largest variety of signals and were recently reported as key effectors of cell–cell communication in pancreatic cancer, from its development to its evolution as well as its ability to resist available treatments. This review focuses on extracellular vesicles-mediated communication between different cellular components of pancreatic tumors, from the modulation of cellular activities and abilities to their biological and physiological relevance. Taking into consideration the intra-tumoral microenvironment and its extracellular-mediated crosstalk as main drivers of pancreatic cancer development should open up new therapeutic windows.

Extracellular Vesicles and Pancreatic Cancer: Insights on the Roles of miRNA, lncRNA, and Protein Cargos in Cancer Progression

Pancreatic cancer (PC) is among the most devastating digestive tract cancers worldwide. This cancer is characterized by poor diagnostic detection, lack of therapy, and difficulty in predicting tumorigenesis progression. Although mutations of key oncogenes and oncosuppressor involved in tumor growth and in immunosurveillance escape are known, the underlying mechanisms that orchestrate PC initiation and progression are poorly understood or still under debate. In recent years, the attention of many researchers has been concentrated on the role of extracellular vesicles and of a particular subset of extracellular vesicles, known as exosomes. Literature data report that these nanovesicles are able to deliver their cargos to recipient cells playing key roles in the pathogenesis and progression of many pancreatic precancerous conditions. In this review, we have summarized and discussed principal cargos of extracellular vesicles characterized in PC, such as miRNAs, lncRNAs, and several proteins, to offer a systematic overview of their function in PC progression. The study of extracellular vesicles is allowing to understand that investigation of their secretion and analysis of their content might represent a new and potential diagnostic and prognostic tools for PC.

Advances in Biological Function and Clinical Application of Small Extracellular Vesicle Membrane Proteins

Small extracellular vesicles are membrane-bound vesicles secreted into extracellular spaces by virtually all types of cells. These carry a large number of membrane proteins on their surface that are incorporated during their biogenesis in cells. The composition of the membrane proteins hence bears the signature of the cells from which they originate. Recent studies have suggested that the proteins on these small extracellular vesicles can serve as biomarkers and target proteins for the diagnosis and treatment of diseases. This article classifies small extracellular vesicle membrane proteins and summarizes their pathophysiological functions in the diagnosis and treatment of diseases.

CD9 inhibition reveals a functional connection of extracellular vesicle secretion with mitophagy in melanoma cells

Tetraspanins are often used as Extracellular Vesicle (EV) detection markers because of their abundance on these secreted vesicles. However, data on their function on EV biogenesis are controversial and compensatory mechanisms often occur upon gene deletion. To overcome this handicap, we have compared the effects of tetraspanin CD9 gene deletion with those elicited by cytopermeable peptides with blocking properties against tetraspanin CD9. Both CD9 peptide or gene deletion reduced the number of early endosomes. CD9 peptide induced an increase in lysosome numbers, while CD9 deletion augmented the number of MVB and EV secretion, probably because of compensatory CD63 expression upregulation. In vivo, CD9 peptide delayed primary tumour cell growth and reduced metastasis size. These effects on cell proliferation were shown to be concomitant with an impairment in mitochondrial quality control. CD9 KO cells were able to compensate the mitochondrial malfunction by increasing total mitochondrial mass reducing mitophagy. Our data thus provide the first evidence for a functional connection of tetraspanin CD9 with mitophagy in melanoma cells.

The Context-Dependent Impact of Integrin-Associated CD151 and Other Tetraspanins on Cancer Development and Progression: A Class of Versatile Mediators of Cellular Function and Signaling, Tumorigenesis and Metastasis

Simple Summary

Tetraspanins are a family of molecules abundantly expressed on the surface of normal or tumor cells. They have been implicated in recruiting or sequestering key molecular regulators of malignancy of a variety of human cancers, including breast and lung cancers, glioblastoma and leukemia. Yet, how their actions take place remains mysterious due to a lack of traditional platform for molecular interactions. The current review digs into this mystery by examining findings from recent studies of multiple tetraspanins, particularly CD151. The molecular basis for differential impact of tetraspanins on tumor development, progression, and spreading to secondary sites is highlighted, and the complexity and plasticity of their control over tumor cell activities and interaction with their surroundings is discussed. Finally, an outlook is provided regarding tetraspanins as candidate biomarkers and targets for the diagnosis and treatment of human cancer.

Abstract

As a family of integral membrane proteins, tetraspanins have been functionally linked to a wide spectrum of human cancers, ranging from breast, colon, lung, ovarian, prostate, and skin carcinomas to glioblastoma. CD151 is one such prominent member of the tetraspanin family recently suggested to mediate tumor development, growth, and progression in oncogenic context- and cell lineage-dependent manners. In the current review, we summarize recent advances in mechanistic understanding of the function and signaling of integrin-associated CD151 and other tetraspanins in multiple cancer types. We also highlight emerging genetic and epigenetic evidence on the intrinsic links between tetraspanins, the epithelial-mesenchymal transition (EMT), cancer stem cells (CSCs), and the Wnt/β-catenin pathway, as well as the dynamics of exosome and cellular metabolism. Finally, we discuss the implications of the highly plastic nature and epigenetic susceptibility of CD151 expression, function, and signaling for clinical diagnosis and therapeutic intervention for human cancer.