A State-of-the-Art Review on the Recent Advances in Exosomes in Oncogenic Virus

Background and Aims

Oncogenic viruses are responsible for approximately 12% of human malignancies, influencing various cancer processes through intricate interactions with host cells. Exosomes (EXOs), nanometric-sized microvesicles involved in cell communication, have emerged as critical mediators in these interactions. This review aims to explore the mechanisms by which EXOs produced by cells infected with oncogenic viruses promote cancer growth, enhance viral transmissibility, and act as immunomodulators.

Methods

A comprehensive review was conducted, focusing on recent studies highlighting the mechanisms by which EXOs facilitate the oncogenic potential of viruses. The analysis included the characterization of exosomal content, such as microRNAs (miRNAs) and proteins, and their effects on tumor microenvironments and immune responses. A search was performed using databases including PubMed, ScienceDirect, and Google Scholar. MeSH keywords related to EXOs, oncogenic viruses, and cancer were used to retrieve relevant review, systematic, and research articles.

Results

Findings indicate that EXOs from oncogenic virus-infected cells carry viral components that facilitate infection and inflammation. These EXOs alter the tumor microenvironment, contributing to the development of virus-associated cancers. Additionally, the review highlights the growing interest among researchers regarding the implications of EXOs in cancer progression and their potential role in enhancing the oncogenicity of viruses.

Conclusion

The findings underscore the pivotal role of EXOs in mediating the oncogenic effects of viruses, suggesting that targeting exosomal pathways may provide new therapeutic avenues for managing virus-associated cancers. Further research is needed to fully elucidate the functional mechanisms of EXOs in viral oncogenesis.

Role of exosomes in the communication and treatment between OSCC and normal cells

Oral squamous cell carcinoma (OSCC) is a prevalent cancer that needs new therapeutic targets due to the poor postoperative prognosis in patients. Exosomes are currently one of important research areas owing to their unique properties. Exosomes are capable of acting as drug transporters, as well as facilitating interactions between OSCC and normal cells. Exosomes can be detected in body fluids such as blood, urine, cerebrospinal fluid, and bile. When exosomes are released from donor cells, they can carry various bioactive molecules to recipient cells, where these molecules participate in biological processes. This review highlights the mechanisms of exosome transfer between normal and OSCC cells. Exosomes isolated from donor OSCC cells can carry circular RNAs (circRNAs), long non-coding RNAs (lncRNAs), and microRNAs (miRNAs) and play a role in signaling processes in the recipient OSCC cells, human umbilical vein endothelial cells, and macrophages. Exosomes secreted by carcinoma-associated fibroblasts, macrophages, and stem cells can also enter the recipient OSCC cells and modulate signaling events in these cells. Exosomes isolated from OSCC plasma, serum, and saliva are also associated with OSCC prognosis. Furthermore, while exosomes were shown to be associated with chemotherapy resistance in OSCC, they can also be used for drug delivery during OSCC treatment. In this paper, we reviewed the molecular mechanisms and functions of exosomes from different cell sources in OSCC cells, providing a basis for diagnosis and prognosis prediction in OSCC patients, and offering guidance for the design of molecular targets carried by exosomes in OSCC.

Moving from conventional to adaptive risk stratification for oropharyngeal cancer

Oropharyngeal cancer (OPC) poses a complex therapeutic dilemma for patients and oncologists alike, made worse by the epidemic increase in new cases associated with the oncogenic human papillomavirus (HPV). In a counterintuitive manner, the very thing which gives patients hope, the high response rate of HPV-associated OPC to conventional chemo-radiation strategies, has become one of the biggest challenges for the field as a whole. It has now become clear that for ~30-40% of patients, treatment intensity could be reduced without losing therapeutic efficacy, yet substantially diminishing the acute and lifelong morbidity resulting from conventional chemotherapy and radiation. At the same time, conventional approaches to de-escalation at a population (selected or unselected) level are hampered by a simple fact: we lack patient-specific information from individual tumors that can predict responsiveness. This results in a problematic tradeoff between the deleterious impact of de-escalation on patients with aggressive, treatment-refractory disease and the beneficial reduction in treatment-related morbidity for patients with treatment-responsive disease. True precision oncology approaches require a constant, iterative interrogation of solid tumors prior to and especially during cancer treatment in order to tailor treatment intensity to tumor biology. Whereas this approach can be deployed in hematologic diseases with some success, our ability to extend it to solid cancers with regional metastasis has been extremely limited in the curative intent setting. New developments in metabolic imaging and quantitative interrogation of circulating DNA, tumor exosomes and whole circulating tumor cells, however, provide renewed opportunities to adapt and individualize even conventional chemo-radiation strategies to diseases with highly variable biology such as OPC. In this review, we discuss opportunities to deploy developing technologies in the context of institutional and cooperative group clinical trials over the coming decade.

Engineered small extracellular vesicles as a novel platform to suppress human oncovirus-associated cancers

BACKGROUND

Cancer, as a complex, heterogeneous disease, is currently affecting millions of people worldwide. Even if the most common traditional treatments, namely, chemotherapy (CTx) and radiotherapy (RTx), have been so far effective in some conditions, there is still a dire need for novel, innovative approaches to treat types of cancer. In this context, oncoviruses are responsible for 12% of all malignancies, such as human papillomavirus (HPV), Merkel cell polyomavirus (MCPyV), Epstein-Barr virus (EBV), human herpesvirus 8 (HHV-8), as well as hepatitis B virus (HBV) and hepatitis C virus (HCV), and the poorest in the world also account for 80% of all human cancer cases. Against this background, nanomedicine has developed nano-based drug delivery systems (DDS) to meet the demand for drug delivery vectors, e.g., extracellular vesicles (EVs). This review article aimed to explore the potential of engineered small EVs (sEVs) in suppressing human oncovirus-associated cancers.

METHODS

Our search was conducted for published research between 2000 and 2022 using several international databases, including Scopus, PubMed, Web of Science, and Google Scholar. We also reviewed additional evidence from relevant published articles.

RESULTS

In this line, the findings revealed that EV engineering as a new field is witnessing the development of novel sEV-based structures, and it is expected to be advanced in the future. EVs may be further exploited in specialized applications as therapeutic or diagnostic tools. The techniques of biotechnology have been additionally utilized to create synthetic bilayers based on the physical and chemical properties of parent molecules via a top-down strategy for downsizing complicated, big particles into nano-sized sEVs.

CONCLUSION

As the final point, EV-mediated treatments are less toxic to the body than the most conventional ones, making them a safer and even more effective option. Although many in vitro studies have so far tested the efficacy of sEVs, further research is still needed to develop their potential in animal and clinical trials to reap the therapeutic benefits of this promising platform.

Exosomes: Mediators of cellular communication in potentially malignant oral lesions and head and neck cancers

Exosomes are a unique type of extracellular vesicles that contain a plethora of biological cargo such as miRNA, mRNA, long non-coding RNA, DNA, proteins and lipids. Exosomes serve as very effective means of intercellular communication. Due the presence of a lipid bilayer membrane, exosomes are resistant to degradation and are highly stable. This makes them easily identifiable in blood and other bodily fluids such as saliva. The exosomes that are secreted from a parent cell directly release their contents into the cytoplasm of a recipient cell and influence their cellular activity and function. Exosomes can also transfer their content between cancer cells and normal cells and regulate the tumor microenvironment. Exosomes play a vital role in tumor growth, tumor invasion and metastasis. Exosomes provide a multitude of molecular and genetic information and have become valuable indicators of disease activity at the cellular level. This review explores the molecular characteristics of exosomes and the role that exosomes play in the tumorigenesis pathway of potentially malignant oral lesions and head and neck cancers The application of exosomes in the treatment of oral cancers is also envisioned. Exosomes are very small and can easily pass through various biological barriers, making them very good delivery vectors for therapeutic drugs as well as to selectively induce DNA's mRNA and miRNAs into targeted cancer cells.

Small extravesicular microRNA in head and neck squamous cell carcinoma and its potential as a liquid biopsy for early detection

BACKGROUND

The objective was to assess secretion of small extracellular vesicular microRNA (exo-miRNA) in head and neck squamous cell carcinoma (HNSCC) according to human papillomavirus (HPV) status, and determine the translational potential as a liquid biopsy for early detection.

METHODS

This study employed a combination of cell culture and case-control study design using archival pretreatment serum. Small extracellular vesicles (sEV) were isolated from conditioned culture media and human serum samples via differential ultracentrifugation. miRNA-sequencing was performed on each sEV isolate.

RESULTS

There were clear exo-miRNA profiles that distinguished HNSCC cell lines from nonpathologic oral epithelial control cells. While there was some overlap among profiles across all samples, there were apparent differences in exo-miRNA profiles according to HPV-status. Importantly, differential exo-miRNA profiles were also apparent in serum from early-stage HNSCC cases relative to cancer-free controls.

CONCLUSIONS

Our findings indicate that exo-miRNA are highly dysregulated in HNSCC and support the potential of exo-miRNA as biomarkers for HNSCC.

Salivary non-apoptotic tumoral microvesicles: A potential progressive marker in oral cancer patients

Tumour cell-secreted microvesicles (MVs) contribute immensely to tumour progression. However, the role of tumoral salivary MVs in oral squamous cell carcinoma (OSCC) remains unclear. Herein, we elucidated the role of non-apoptotic salivary tumoral MVs in OSCC development, especially relating to the migration ability. We purified and compared non-apoptotic salivary tumoral MVs from 63 OSCC patients and orthotopic OSCC mice model. Next, we compared the protein difference between apoptotic and non-apoptotic MVs by Western blot, proteomics and flow cytometry from saliva and CAL27 cells. Finally, we collected the non-apoptotic MVs and co-cultured with normal oral epithelial cells, the migration ability was examined by wound healing assay and Western blot assay. Our results indicated that the levels of non-apoptotic tumoral S-MVs were significantly higher in OSCC patients with T3 to T4 stages than in patients with T1 to T2 stages or healthy donors. In OSCC mice model, we found elevations of non-apoptotic tumoral MVs associated with tumoral volume. EGFR overexpression increased the generation of non-apoptotic tumoral MVs which could significantly promote normal epithelial cell migration. In conclusion, elevated levels of non-apoptotic tumoral S-MVs are associated with clinicopathologic features of OSCC patients, implying that non-apoptotic tumoral S-MVs are a potential progressive marker of OSCC.

Current Status, Opportunities, and Challenges of Exosomes in Oral Cancer Diagnosis and Treatment

Oral cancer is one of the most common cancers in the world, with more than 300,000 cases diagnosed each year, of which oral squamous cell carcinoma accounts for more than 90%, with a 5-year survival rate of only 40–60%, and poor prognosis. Exploring new strategies for the early diagnosis and treatment of oral cancer is key to improving the survival rate. Exosomes are nanoscale lipid bilayer membrane vesicles that are secreted by almost all cell types. During the development of oral cancer, exosomes can transport their contents (DNA, RNA, proteins, etc) to target cells and promote or inhibit the proliferation, invasion, and metastasis of oral cancer cells by influencing the host immune response, drug-resistant metastasis, and tumour angiogenesis. Therefore, exosomes have great potential and advantages as biomarkers for oral cancer diagnosis, and as drug delivery vehicles or targets for oral cancer therapy. In this review, we first describe the biogenesis, biological functions, and isolation methods of exosomes, followed by their relationship with oral cancer. Here, we focused on the potential of exosomes as oral cancer biomarkers, drug carriers, and therapeutic targets. Finally, we provide an insightful discussion of the opportunities and challenges of exosome application in oral cancer diagnosis and treatment, intending to offer new ideas for the clinical management of oral cancer.

Tumor-derived exosomal microRNA-15b-5p augments laryngeal cancer by targeting TXNIP

Tumor-derived exosomes (EXO) are information carriers of microRNA (miR) in cancer development. Here, we explored the synergism of tumor-derived EXO and miR-15b-5p in laryngeal cancer (LCa). miR-15b-5p and thioredoxin-interacting protein (TXNIP) levels were firstly measured in clinical LCa tissues. The association between miR-15b-5p and TXNIP was determined. miR-15b-5p mimic was transfected into HEP-2 cells, and the corresponding exosomes were extracted. miR-15b-5p mimic-modified EXO were co-cultured with HEP-2 cells, and TXNIP low expression/high expression vector was transfected into HEP-2 cells Finally, cell growth was observed in vitro and in vivo. miR-15b-5p level was high while TXNIP level was low in LCa, and miR-15b-5p negatively modulated TXNIP expression. HEP-2 cells-derived EXO or inhibition of TXNIP enhanced HEP-2 cell growth in vitro and in vivo. Up-regulated miR-15b-5p further strengthened the pro-tumor effect of EXO, but this effect was reversed by overexpression of TXNIP. Overall, tumor-derived exosomal miR-15b-5p augments LCa through targeting down-regulation of TXNIP.

The Potential Role of Exosomes in the Treatment of Brain Tumors, Recent Updates and Advances

Exosomes are small endosomal derived membrane extracellular vesicles that contain cell-specific cargos such as lipid, protein, DNA, RNA, miRNA, long non-coding RNA, and some other cell components that are released into surrounding body fluids upon the fusion of multivesicular bodies (MVB) and the plasma membrane. Exosomes are a one-of-a-kind cell-to-cell communication mechanism that might pave the way for target therapy. The use of exosomes as a therapeutic potential in a variety of cancers has been and is still being investigated. One of the most important of these has been the use of exosomes in brain tumors therapy. Exosome contents play a crucial role in brain tumor progression by providing a favorable niche for tumor cell proliferation. Also, exosomes that are secreted from tumor cells, lead to the protection of tumor cells and their proliferation in the tumor environment by reducing the inflammatory response and suppression of the immune system. Although some treatment protocols such as surgery, chemotherapy, and radiotherapy are common in brain tumors, they do not result in complete remission in the treatment of some malignant and metastatic brain tumors. Identifying, targeting, and blocking exosomes involved in the progression of brain tumors could be a promising way to reduce brain tumor progression. On the other way, brain tumor therapy with effective therapeutic components such as siRNAs, mRNAs, proteins, could be developed. Finally, our research suggested that exosomes of nanoscale sizes might be a useful tool for crossing the blood-brain barrier and delivering effective content. However, further research is needed to fully comprehend the potential involvement of the exosome in brain tumor therapy protocols.

Proteomic Profiling of Ectosomes Derived from Paired Urothelial Bladder Cancer and Normal Cells Reveals the Presence of Biologically-Relevant Molecules

Protein content of extracellular vesicles (EVs) can modulate different processes during carcinogenesis. Novel proteomic strategies have been applied several times to profile proteins present in exosomes released by urothelial bladder cancer (UBC) cells. However, similar studies have not been conducted so far on another population of EVs, i.e., ectosomes. In the present study we used a shotgun nanoLC-MS/MS proteomic approach to investigate the protein content of ectosomes released in vitro by T-24 UBC cells and HCV-29 normal ureter epithelial cells. In addition, cancer-promoting effects exerted by UBC-derived ectosomes on non-invasive cells in terms of cell proliferation and migratory properties were assessed. In total, 1158 proteins were identified in T-24-derived ectosomes, while HCV-29-derived ectosomes contained a lower number of 259 identified proteins. Qualitative analysis revealed 938 proteins present uniquely in T-24-derived ectosomes, suggesting their potential applications in bladder cancer management as diagnostic and prognostic biomarkers. In addition, T-24-derived ectosomes increased proliferation and motility of recipient cells, likely due to the ectosomal transfer of the identified cancer-promoting molecules. The present study provided a focused identification of biologically relevant proteins in UBC-derived ectosomes, confirming their role in UBC development and progression, and their applicability for further biomarker-oriented studies in preclinical or clinical settings.

Separation of distinct exosome subpopulations: isolation and characterization approaches and their associated challenges

Exosomes are nano-sized extracellular vesicles that serve as a communications system between cells and have shown tremendous promise as liquid biopsy biomarkers in diagnostic, prognostic, and even therapeutic use in different human diseases. Due to the natural heterogeneity of exosomes, there is a need to separate exosomes into distinct biophysical and/or biochemical subpopulations to enable full interrogation of exosome biology and function prior to the possibility of clinical translation. Currently, there exists a multitude of different exosome isolation and characterization approaches which can, in limited capacity, separate exosomes based on biophysical and/or biochemical characteristics. While notable reviews in recent years have reviewed these approaches for bulk exosome sorting, we herein present a comprehensive overview of various conventional technologies and modern microfluidic and nanotechnological advancements towards isolation and characterization of exosome subpopulations. The benefits and limitations of these different technologies to improve their use for distinct exosome subpopulations in clinical practices are also discussed. Furthermore, an overview of the most commonly encountered technical and biological challenges for effective separation of exosome subpopulations is presented.

The role of Exosomes in the Pathogenesis of Nasopharyngeal Carcinoma and the involved Clinical Application

Exosomes are nanoscale membrane vesicles, which carry biologically active substances of their cell of origin and play an important role in signal transduction and intercellular communication. At present, exosomes have been identified as a promising non-invasive liquid biopsy biomarker in the tissues and circulating blood of nasopharyngeal carcinoma (NPC) and found to participate in regulating pathophysiological process of the tumor. We here review recent insights gained into the molecular mechanisms of exosome-induced cell growth, angiogenesis, metastasis, immunosuppression, radiation resistance and chemotherapy resistance in the development and progression of NPC, as well as the clinical application of exosomes as diagnostic biomarkers and therapeutic agents. We also discuss the limitations and challenges in exosome application. We hope this review may provide some references for the use of exosomes in clinical intervention.

Recent advances in point-of-care diagnostics for oral cancer

Early-stage diagnosis is a crucial step in reducing the mortality rate in oral cancer cases. Point-of-care (POC) devices for oral cancer diagnosis hold great future potential in improving the survival rates as well as the quality of life of oral cancer patients. The conventional oral examination followed by needle biopsy and histopathological analysis have limited diagnostic accuracy. Besides, it involves patient discomfort and is not feasible in resource-limited settings. POC detection of biomarkers and diagnostic adjuncts has emerged as non- or minimally invasive tools for the diagnosis of oral cancer at an early stage. Various biosensors have been developed for the rapid detection of oral cancer biomarkers at the point-of-care. Several optical imaging methods have also been employed as adjuncts to detect alterations in oral tissue indicative of malignancy. This review summarizes the different POC platforms developed for the detection of oral cancer biomarkers, along with various POC imaging and cytological adjuncts that aid in oral cancer diagnosis, especially in low resource settings. Various immunosensors and nucleic acid biosensors developed to detect oral cancer biomarkers are summarized with examples. The different imaging methods used to detect oral tissue malignancy are also discussed herein. Additionally, the currently available commercial devices used as adjuncts in the POC detection of oral cancer are emphasized along with their characteristics. Finally, we discuss the limitations and challenges that persist in translating the developed POC techniques in the clinical settings for oral cancer diagnosis, along with future perspectives.

Evaluation of exosome derivatives as bio-informational reprogramming therapy for cancer

Exosomes are nanoparticle sized (100 ± 50 nm) extracellular vesicles (ECVs) that play important roles in cell-to-cell communication. They do this by utilizing their natural ability to shuttle signaling molecules across the cellular microenvironment and promote paracrine signaling. Currently, exosomes are being explored for their potential as therapeutic agents for various degenerative diseases including cancer. The rationale behind their therapeutic ability is that they can transfer signaling biomolecules, and subsequently induce metabolic and physiological changes in diseased cells and tissues. In addition, exosomes can be used as a drug delivery system and may be very effective at reducing toxicity and increasing bioavailability of therapeutic molecules and drugs. Although exosomes were first believed to be a waste product of the cell, current research has demonstrated that these particles can serve as modulators of the immune system, act as cancer biomarkers, cause re-differentiation of cancer cells, and induce apoptosis in diseased cells. Extensive research has been performed specifically using amniotic fluid-derived extracellular vesicles, named "cytosomes". While the use of cytosomes in clinical application is still in the early stages, researchers have shown great potential for these EVs in regenerative medicine as immune modulators, in controlling microbial infection and by inducing tissue repair through the activation of endogenous, tissue-specific stem cells. This review emphasizes the capabilities of specific subsets of extracellular vesicles that can potentially be used for cancer therapy, principally as a source of bi-informational reprogramming for malignant cells.

Extracellular Vesicles in Liquid Biopsies: Potential for Disease Diagnosis

Liquid biopsy is conducted through minimally invasive or noninvasive procedures, and the resulting material can be subjected to genomic, proteomic, and lipidomic analyses for early diagnosis of cancers and other diseases. Extracellular vesicles (EVs), one kind of promising tool for liquid biopsy, are nanosized bilayer particles that are secreted by all kinds of cells and that carry cargoes such as lipids, proteins, and nucleic acids, protecting them from enzymatic degradation in the extracellular environment. In this review, we provide a comprehensive introduction to the properties and applications of EVs, including their biogenesis, contents, sample collection, isolation, and applications in diagnostics based on liquid biopsy.

Liquid biopsy in head and neck squamous cell carcinoma: circulating tumor cells, circulating tumor DNA, and exosomes

Introduction: Head and neck squamous cell carcinoma (HNSCC) is one of the most common cancers worldwide. Due to a lack of reliable markers, HNSCC patients are usually diagnosed at a late stage, which will lead to a worse outcome. Therefore, it is critical to improve the clinical management of cancer patients. Nowadays, the development of liquid biopsy enables a minimally invasive manner to extract molecular information from HNSCCs. Thus, this review aims to outline the clinical value of liquid biopsy in early detection, real-time monitoring, and prognostic evaluation of HNSCC. Areas covered: This comprehensive review focused on the characteristics as well as clinical applications of three liquid biopsy markers (CTCs, ctDNA, and exosomes) in HNSCC. What is more, it is promising to incorporate machine learning and 3D organoid models in the liquid biopsy of HNSCC. Expert opinion: Liquid biopsy provides a noninvasive technique to reflect the inter and intra-lesional heterogeneity through the detection of tumor cells or materials released from the primary and secondary tumors. Recently, some evolving technologies have the potential to combine with liquid biopsy to improve clinical management of HNSCC patients.

Diagnostic value of exosomal circMYC in radioresistant nasopharyngeal carcinoma

BACKGROUND

The relationship between circulating exosomal circular RNA (circRNA) and prognosis of patients with nasopharyngeal carcinoma (NPC) remain unknown. This study focused on the expression of exosomal circMYC and its relationship with the recurrence and prognosis of patients with NPC.

METHODS

The circulating exosomes were obtained from 210 patients with NPC. Quantitative polymerase chain reaction, 5-ethynyl-2'-deoxyuridine (EdU) staining, colony formation, and bioinformatic analysis were performed.

RESULTS

Circulating exosomal circMYC was significantly increased in patients with NPC and was associated with tumor size, lymph node metastasis, TNM stage, survival rate, and disease recurrence. Gain-functional and loss-functional experiments revealed that overexpression of circMYC promoted cell proliferation and reduce radiosensitivity, while knockdown of circMYC inhibited cell proliferation and enhanced radiotherapy.

CONCLUSION

circMYC is an oncogene in NPC cells and can enhance the radiotherapy resistance of NPC cells. Circulating exosomal circMYC can be used as a potential therapeutic target for NPC.

Extracellular Vesicles Released by Tumor Endothelial Cells Spread Immunosuppressive and Transforming Signals Through Various Recipient Cells

Head and neck squamous cell carcinoma (HNSCC) has a high recurrence and metastatic rate with an unknown mechanism of cancer spread. Tumor inflammation is the most critical processes of cancer onset, growth, and metastasis. We hypothesize that the release of extracellular vesicles (EVs) by tumor endothelial cells (TECs) induce reprogramming of immune cells as well as stromal cells to create an immunosuppressive microenvironment that favor tumor spread. We call this mechanism as non-metastatic contagious carcinogenesis. Extracellular vesicles were collected from primary HNSCC-derived endothelial cells (TEC-EV) and were used for stimulation of peripheral blood mononuclear cells (PBMCs) and primary adipose mesenchymal stem cells (ASCs). Regulation of ASC gene expression was investigated by RNA sequencing and protein array. PBMC, stimulated with TEC-EV, were analyzed by enzyme-linked immunosorbent assay and fluorescence-activated cell sorting. We validated in vitro the effects of TEC-EV on ASCs or PBMC by measuring invasion, adhesion, and proliferation. We found and confirmed that TEC-EV were able to change ASC inflammatory gene expression signature within 24-48 h. TEC-EV were also able to enhance the secretion of TGF-β1 and IL-10 by PBMC and to increase T regulatory cell (Treg) expansion. TEC-EV carry specific proteins and RNAs that are responsible for Treg differentiation and immune suppression. ASCs and PBMC, treated with TEC-EV, enhanced proliferation, adhesion of tumor cells, and their invasion. These data indicate that TEC-EV exhibit a mechanism of non-metastatic contagious carcinogenesis that regulates tumor microenvironment and reprograms immune cells to sustain tumor growth and progression.

Upregulation of circ_0000199 in circulating exosomes is associated with survival outcome in OSCC

Studies have found that circRNA in exosomes is associated with oral squamous cell carcinoma (OSCC) progression. In this study, we examined the expression of circ_0000199 in circulating exosomes from patients with OSCC and its role in the evaluation of relapse and prognosis. Real‐time quantitative reverse transcription–polymerase chain reaction was performed to assess circ_0000199 expression in circulating exosomes from 108 patients with OSCC and 50 healthy people. Gain- and loss-functional experiments were performed to assess the role of circ_0000199 on cell proliferation and apoptosis in OSCC cells. Our results showed that the high level of circ_0000199 in circulating exosomes was significantly associated with betel quid chewing, tumor size, lymphatic metastasis, and TNM stage in patients with OSCC. In addition, the patients with high exosomal circ_0000199 had higher tumor recurrence rate and higher mortality rate than the patients with low exosomal circ_0000199. Overexpression of circ_0000199 promoted, while knockdown of circ_0000199 inhibited OSCC cell growth. Bioinformatics analysis predicted that circ_0000199 interacted with miR-145-5p and miR-29b-3p simultaneously, which were involved in multiple tumor‐related signaling pathways. In conclusion, upregulation of circ_0000199 in circulating exosomes from patients with OSCC is positively associated with poor survival outcome. Circulating exosomal circ_0000199 can be used as a biomarker and potential therapeutic target for OSCC.

Salivary exosomes: properties, medical applications, and isolation methods

Salivary exosomes are extracellular vesicles (EVs) with abundant CD63 immunoreactivity on their surface. Based on their size and protein composition, these exosomes can be categorized into two classes of exosomes I (mean diameter of 83.5 nm) and II (mean diameter of 40.5 nm). We have attempted to review the features of these exosomes, including origin, composition, separation methods, and their application in medicine. Not only the composition of salivary exosomes is invaluable in term of diagnosis, but can also afford an understanding in roles of the contents and components of these exosomes in the fundamental pathophysiologic processes of different diseases. since these EVs can cross the epithelial barriers they may be essential for transporting of multifarious components from the blood into saliva. Thus, in comparison to other bodily fluids, salivary exosomes are probably a better and accessible tool to examine the function of exosomes in the diagnosis and treatment of disease.

Circulating extracellular vesicle-associated TGFβ3 modulates response to cytotoxic therapy in head and neck squamous cell carcinoma

Management of locally advanced head and neck squamous cell carcinoma (HNSCC) requires a multi-prong approach comprising surgery, radiation and/or chemotherapy, yet outcomes are limited. This is largely due to a paucity of biomarkers that can predict response to specific treatment modalities. Here, we evaluated TGFβ3 protein levels in extracellular vesicles (EVs) released by HNSCC cells as a predictor for response to chemoradiation therapy (CRT). To this end, specific EV-fractions were isolated from cell lines or HNSCC patient plasma, and TGFβ3 protein was quantified. In patients treated with CRT, TGFβ3 levels were found to be significantly higher in plasma EV-fractions or non-responders compared with responders. High levels of TGFβ3 levels in Annexin V-EVs were associated with the worst progression-free survival. In vitro experiments demonstrated that TGFβ3 silencing sensitized HNSCC cells to cytotoxic therapies, and this phenotype could be rescued by treatment with exogenous. In addition, specific EV-fractions shed by cisplatin-resistant cells were sufficient to transfer the resistant phenotype to sensitive cells through activation of TGFβ-signaling pathway. Therefore, our data show that TGFβ3 transmitted through EV plays a significant role in response to cytotoxic therapy, which can be exploited as a potential biomarker for CRT response in HNSCC patients treated with curative intent.

Caries Increment and Salivary Microbiome during University Life: A Prospective Cohort Study

The purpose of this 3-year prospective cohort study was to explore the relationship between an increase in dental caries and oral microbiome among Japanese university students. We analyzed 487 students who volunteered to receive oral examinations and answer baseline (2013) and follow-up (2016) questionnaires. Of these students, salivary samples were randomly collected from 55 students at follow-up and analyzed using next-generation sequencing. Students were divided into two groups: increased group (Δdecayed, missing, and filled teeth (ΔDMFT) score increased during the 3-year period) and non-increased group (ΔDMFT did not increase). Thirteen phyla, 21 classes, 32 orders, 48 families, 72 genera, and 156 species were identified. Microbial diversity in the increased group (n = 14) was similar to that in the non-increased group (n = 41). Relative abundances of the family Prevotellaceae (p = 0.007) and genera Alloprevotella (p = 0.007) and Dialister (p = 0.039) were enriched in the increased group compared with the non-increased group. Some bacterial taxonomic clades were differentially present between the two groups. These results may contribute to the development of new dental caries prevention strategies, including the development of detection kits and enlightenment activities for these bacteria.

Potential oncogenic roles of mutant-p53-derived exosomes in the tumor-host interaction of head and neck cancers

The wide-ranging collection of malignancies arising at the upper aerodigestive tract is categorized as head and neck cancer (HNC), the sixth most prevalent cancer worldwide. Infection with human papillomavirus (HPV) or exposure to carcinogens is the leading causes of HPV+ and HPV- HNCs development, respectively. HPV+ and HPV- HNCs are different in clinical and molecular aspects. Specifically, HPV- HNCs tightly associate with missense mutants of the TP53 gene (encoding for the p53 protein), suggesting a central role for mutant p53 gain-of-function (GOF) in driving tumorigenesis. In contrast, in HPV + HNC, the sequence of TP53 typically remains intact, while the protein is degraded. In tumor cells, the status of the TP53 gene affects the cargo of secreted exosomes. In this review, we describe the accumulated knowledge regarding the involvement of exosomes and p53 on cellular interactions between HPV+ and HPV- HNC cells, and the surrounding tumor microenvironment (TME). Moreover, we envision how TP53 status may determine exosomes cargo in HNC, and, consequently, modify the TME. The potential roles of exosomes described herein are based on both our studies and the studies of others on mutant p53-derived exosomes. Specifically, we showed how exosomes are shed by cancer cells harboring mutant p53 communicate with tumor-associated macrophages in the colon as well as with cancer-associated fibroblasts in the lung, creating immunosuppressive conditions and promoting invasiveness. Altogether, exosomes in HNC in the context of TP53 status are understudied and extensive research is required to shed light on the biology of HPV+ and HPV- HNC.

Exosomes in Head and Neck Squamous Cell Carcinoma

Exosomes are small membranous vesicles that contain proteins, lipids, genetic material, and metabolites with abundant information from parental cells. Exosomes carry and deliver bioactive contents that can reprogram the functions of recipient cells and modulate the tumor microenvironment to induce pathological events through cell-to-cell communication and signal transduction. Tumor-derived exosomes (TDEs) in head and neck squamous cell carcinoma (HNSCC) are involved in most aspects of cancer initiation, invasion, progression, immunoregulation, therapeutic applications, and treatment resistance. In addition, HNSCC-derived exosomes can be used to obtain information on diagnostic and therapeutic biomarkers in circulating blood and saliva. Currently, the biology, mechanisms, and applications of TDEs in HNSCC are still unclear, and further research is required. In this review, we discuss various aspects of exosome biology, including exosomal components, exosomal biomarkers, and molecular mechanisms involved in immunoregulation, cancer metastasis, and therapy resistance. We also describe recent applications to update our understanding of exosomes in HNSCC.

Head and neck cancer: searching for genomic and epigenetic biomarkers in body fluids - the state of art

Head and neck squamous cell carcinoma (HNSCC) affects multiple sites of the upper aerodigestive tract and exhibited high incidence and mortality worldwide, being frequently diagnosed at advanced stage. Early detection of HNSCC plays a crucial role in a successful therapy. In the last years, the survival rates of these tumors have not improved significantly due to the late diagnosis and the lack of precise disease biomarkers and targeted therapies. The introduction in the clinical practice of body fluids to detect and analyze circulating tumor cells (CTCs), circulating tumor DNA (ctDNA) and exosomes provides a minimally or non-invasive method also called as liquid biopsy for diagnostic and prognostic biomarkers detection, representing a shift of paradigm in precision medicine through the revolution in the way to perform HNSCC diagnosis and to screen high risk population. Despite the use of body fluids being an emergent and up-to date issue to early diagnosis HNSCC and their recurrences, no strategy has yet proven to be consistently effective and able to be translated to clinical application in the routine clinical management of these patients. In this review we will discuss the recent discoveries using blood and saliva to identify biomarkers for the early detection and prognosis of HNSCC.

Dynamic secretome of bone marrow-derived stromal cells reveals a cardioprotective biochemical cocktail

Transplanted stromal cells have demonstrated considerable promise as therapeutic agents in diverse disease settings. Paracrine signaling can be an important mediator of these therapeutic effects at the sites of acute or persistent injury and inflammation. As many stromal cell types, including bone marrow-derived stromal cells (BMSCs), display tissue-specific responses, there is a need to explore their secretory dynamics in the context of tissue and injury type. Paracrine signals are not static, and could encode contextual dynamics in the kinetic changes of the concentrations of the secreted ligands. However, precise measurement of dynamic and context-specific cellular secretory signatures, particularly in adherent cells, remains challenging. Here, by creating an experimental and computational analysis platform, we reconstructed dynamic secretory signatures of cells based on a very limited number of time points. By using this approach, we demonstrate that the secretory signatures of CD133-positive BMSCs are uniquely defined by distinct biological contexts, including signals from injured cardiac cells undergoing oxidative stress, characteristic of cardiac infarction. Furthermore, we show that the mixture of recombinant factors reproducing the dynamics of BMSC-generated secretion can mediate a highly effective rescue of cells injured by oxidative stress and an improved cardiac output. These results support the importance of the dynamic multifactorial paracrine signals in mediating remedial effects of stromal stem cells, and pave the way for stem cell-inspired cell-free treatments of cardiac and other injuries.

Deciphering nasopharyngeal carcinoma pathogenesis via proteomics

Introduction: Nasopharyngeal carcinoma (NPC) is a distinct head and neck squamous cell carcinoma in its etiological association of Epstein-Barr virus (EBV) infection, hidden anatomical location, remarkable racial and geographical distribution, and high incidence of locoregional recurrence or metastasis. Thanks to the advancements in proteomics in recent decades, more understanding of the disease etiology, carcinogenesis, and progression has been gained, potentially deciphering the molecular characteristics of the malignancy. Areas covered: In this review, we provide an overview of the proteomic aberrations that are likely involved or drive NPC development and progression, focusing on the contributions of major EBV-encoded factors, intercommunication with environment, protein features of high metastasis and therapy resistance, and protein-protein interactions that allow NPC cells to evade immune recognition and elimination. Finally, multistep carcinogenesis and subtypes of NPC from a proteomic perspective are inquired. Expert commentary: Proteomic studies have covered various aspects involved in NPC pathogenesis, yet much remains to be uncovered. Coherent study designs, optimal conditions for obtaining high-quality data, and compelling interpretation are critical in ensuring the emergence of good science out of NPC proteomics. NPC proteogenomics and proteoform analysis are two promising fields to promote the application of the proteomic findings from bench to bedside.

Evaluation of Plasma Extracellular Vesicle MicroRNA Signatures for Lung Adenocarcinoma and Granuloma With Monte-Carlo Feature Selection Method

Extracellular Vesicle (EV) is a compilation of secreted vesicles, including micro vesicles, large oncosomes, and exosomes. It can be used in non-invasive diagnosis. MicroRNAs (miRNAs) processed by exosomes can be detected by liquid biopsy. To objectively evaluate the discriminative ability of miRNAs from whole plasma, EV and EV-free plasma, we analyzed the miRNA expression profiles in whole plasma, EV and EV-free plasma of 10 lung adenocarcinoma and 9 granuloma patients. With Monte-Carlo feature selection method, the top discriminative miRNAs in whole plasma, EV and EV-free plasma were identified, and they were quite different. Using the Repeated Incremental Pruning to Produce Error Reduction (RIPPER) method, we learned the classification rules: in whole plasma, granuloma patients did not express hsa-miR-223-3p while the lung adenocarcinoma patients expressed hsa-miR-223-3p; in EV, the hsa-miR-23b-3p was highly expressed in granuloma patients but not lung adenocarcinoma patients; in EV-free plasma, hsa-miR-376a-3p was expressed in granuloma patients but barely expressed in lung adenocarcinoma patients. For prediction performance, whole plasma had the highest weighted accuracy and EV outperformed EV-free plasma. Our results suggested that EV can be used as lung cancer biomarker. However, since it is less stable and not easy to detect, there are still technological difficulties to overcome.

A preliminary investigation of circulating extracellular vesicles and biomarker discovery associated with treatment response in head and neck squamous cell carcinoma

BACKGROUND

There is a paucity of plasma-based biomarkers that prospectively segregate the outcome of patients with head and neck squamous-cell carcinoma (HNSCC) treated with chemoradiation therapy (CRT). Plasma extracellular vesicles (EVs) might be an alternative source for discovery of new specific markers present in patients with HNSCC, which could help to re-direct patients to appropriate curative therapies without delay.

METHODS

In order to identify new markers in plasma compartments, Cholerae toxin B chain (CTB) and Annexin V (AV) were used to isolate EVs from pooled plasma samples from patients with locally advanced HNSCC who responded (CR, n = 6) or presented incomplete response (NR, n = 6) to CRT. The crude plasma and EVs cargo were screened by antibody array.

RESULTS

Of the 370 polypeptides detected, 119 proteins were specific to NR patients while 38 were exclusive of the CR subjects. The Gene Set Enrichment Analysis (GSEA) and Search Tool for the Retrieval of Interacting Genes (STRING) database analysis indicated that the content of circulating plasma EVs might have a relevant function for the tumor intercellular communication in the HNSCC patients.

CONCLUSION

This study provides a list of potential markers present in plasma compartments that might contribute to the development of tools for prediction and assessment of CRT response and potentially guide therapeutic decisions in this context.

Role of tumor‑derived extracellular vesicles in cancer progression and their clinical applications (Review)

Extracellular vesicles (EVs), including micro‑vesicles and exosomes, are heterogeneous small membranous vesicles shed from the surface of myriad cells and are crucial in mediating intercellular communication. The vertical trafficking of cargo to the plasma membrane and subsequent redistribution of surface lipids may contribute to EV formation. Tumor‑derived extracellular vesicles (TD‑EVs) can carry complex, bioactive cargo, such as nucleic acids and proteins, during tumor metastasis. Paracrine information gets relayed by TD‑EVs to adjacent tumor cells and this allows a crosstalk between malignant cells. These structures may even move to a distant metastatic lesion and modulate the tumor microenvironment to form a premetastatic niche. Thus, TD‑EVs might be potential biomarkers for tumor development and metastasis. Additionally, EVs are promising candidates for use as cell‑free vaccines or as vehicles for the delivery of specific tumor therapeutic molecules. Genetically modified microvesicles and engineered exosomes have shed light on a novel strategy for tumor‑targeted gene therapy. This review focuses on the role of EVs in tumor development and metastasis and their possible applications in the advanced diagnosis and therapy of cancer and personalized medicine.

FTIR-based spectrum of salivary exosomes coupled with computational-aided discriminating analysis in the diagnosis of oral cancer

PURPOSE

To determine the Fourier-transform infrared (FTIR) spectra of salivary exosomes from oral cancer (OC) patients and healthy individuals (HI) and to assess its diagnostic potential using computational-aided models.

METHODS

Whole saliva samples were collected from 21 OC patients and 13 HI. Exosomes were pelleted using differential centrifugation (12,000g, 120,000g). The mid-infrared (IR) absorbance spectra (900-5000 cm- 1 range) were measured using MIR8025 Oriel Fourier-transform IR equipped with a PIKE MIRacle ZnSe attenuated total reflectance attachment. Machine learning techniques, utilized to build discrimination models for the absorbance data of OC and HI, included the principal component analysis-linear discriminant analysis (PCA-LDA) and support vector machine (SVM) classification. Sensitivity, specificity and the area under the receiver operating characteristic curve were calculated.

RESULTS

IR spectra of OC were consistently different from HI at 1072 cm- 1 (nucleic acids), 2924 cm- 1 and 2854 cm- 1 (membranous lipids), and 1543 cm- 1 (transmembrane proteins). The PCA-LDA discrimination model correctly classified the samples with a sensitivity of 100%, specificity of 89% and accuracy of 95%, and the SVM showed a training accuracy of 100% and a cross-validation accuracy of 89%.

CONCLUSION

We showed the specific IR spectral signature for OC salivary exosomes, which was accurately differentiated from HI exosomes based on detecting subtle changes in the conformations of proteins, lipids and nucleic acids using optimized artificial neural networks with small data sets. This non-invasive method should be further investigated for diagnosis of oral cancer at its very early stages or in oral lesions with potential for malignant transformation.

Label-free detection of exosomes using a surface plasmon resonance biosensor

The development of a sensitive and specific detection platform for exosomes is highly desirable as they are believed to transmit vital tumour-specific information (mRNAs, microRNAs, and proteins) to remote cells for secondary metastasis. Herein, we report a simple method for the real-time and label-free detection of clinically relevant exosomes using a surface plasmon resonance (SPR) biosensor. Our method shows high specificity in detecting BT474 breast cancer cell-derived exosomes particularly from complex biological samples (e.g. exosome spiked in serum). This approach exhibits high sensitivity by detecting as low as 8280 exosomes/μL which may potentially be suitable for clinical analysis. We believe that this label-free and real-time method along with the high specificity and sensitivity may potentially be useful for clinical settings.

Laminin γ2-enriched extracellular vesicles of oral squamous cell carcinoma cells enhance in vitro lymphangiogenesis via integrin α3-dependent uptake by lymphatic endothelial cells

Oral squamous cell carcinoma (OSCC) LN1-1 cells previously showed greater capacities for lymphangiogenesis and lymph node metastasis compared to their parental OEC-M1 cells, in addition to an ability to enhance the migration and tube formation of lymphatic endothelial cells (LECs). Purified by a series of differential centrifugations and characterized using electron microscopy, dynamic light scattering and western blot, LN1-1 cell-derived extracellular vesicles (LN1-1 EVs) were shown to promote LEC migration, tube formation and uptake by LECs more effectively than did OEC-M1 cell-derived EVs (OEC-M1 EVs). Using stable isotope labeling with amino acids in cell culture/liquid chromatography-tandem mass spectrometry-based proteomic platform, the laminin-332 proteins, including laminin α3, β3 and γ2, were validated as highly expressed proteins in LN1-1 EVs. Clinically, a higher level of laminin-332 was detected in plasma EVs from OSCC patients with lymph node metastasis than in both healthy controls and OSCC patients without lymphatic metastasis, suggesting EV-borne laminin-332 as a novel and noninvasive biomarker for the detection of lymph node metastasis in OSCC. The knockdown of laminin γ2 and inhibition by anti-laminin-332 neutralizing antibodies impaired LN1-1 EV-mediated LEC migration, tube formation and uptake by LECs. Importantly, laminin γ2-deficient EVs showed a reduced ability to drain into lymph nodes in comparison with the control EVs. In addition, the laminin 332/γ2-mediated EV uptake was dependent on integrin α3 but not β1, β4 or α6. Collectively, the uptake of laminin γ2-enriched EVs by LECs enhanced in vitro lymphangiogenesis and EV-borne laminin-332 is thus a viable biomarker for OSCC.

Effects of long noncoding RNA (linc-VLDLR) existing in extracellular vesicles on the occurrence and multidrug resistance of esophageal cancer cells

OBJECTIVE

To investigate the relationship between the expression of linc-VLDLR in extracellular vesicles (EVs) and esophageal carcinomas development and drug resistance.

METHODS

The expression of linc-VLDLR and ABCG2 mRNA in 60 cases of esophageal carcinoma tissue, para-carcinoma tissue and the normal esophagus tissue were detected using Fluorescence quantitative reverse transcription polymerase chain reaction (qRT-PCR). Fifty percent inhibiting concentration (IC50) of adriamycin (ADM) to Eca109 cells was detected by MTT assay, after the treatment of different concentrations of adriamycin (ADM) on esophageal squamous cell carcinoma Eca109 cell line for 24 h. EVs were extracted from culture medium after the treatment of three concentrations of ADM (setting based on the IC50) on Eca109 cells for 24 h. Linc-VLDLR expression in EVs was detected by qRT-PCR. After the treatment of the extracted EVs on virgin Eca109 cells for 48 h, then intervening these cells for 24 h by different concentrations of ADM, the new values of IC50 were detected by MTT assay. Cell cycle, cell apoptosis and ABCG2 protein expression of these Eca109 cells were detected by flow cytometry (FCM). Linc-VLDLR and ABCG2 mRNA expression in these Eca109 cells were detected by qRT-PCR.

RESULTS

Expression of linc-VLDLR and ABCG2 mRNA in esophageal squamous cell carcinoma tissue were significantly higher than that in esophageal atypical hyperplasia and normal esophagus tissue, P < 0.01. After the treatment of ADM on Eca109 cells for 24 h, IC50 of Eca109 cells was detected as (0.44 ± 0.02) μg/mL, thus ADM concentrations of 0, 0.2, 0.4 and 0.8 μg/mL were selected to accomplish the following parts of this study. After four groups of Eca109 cells were treated by ADM in different concentrations separately, extracted EVs from the supernatant of all four groups, then labeling these four groups as EVs1, 2, 3 and 4. Linc-VLDLR expression in EVs4 was significantly higher than that in EVs1-3, P < 0.01. After the treatment of EVs1-4 on virgin Eca109 cells for 48 h, new values of IC50 of Eca109 to ADM were detected by MTT. It was found that the IC50 value of group EVs4 was significantly higher than that of other groups, P < 0.05. Flow cytometry results showed that the proliferation index of Eca109 cells in EVs4 was significantly higher than that in EVs1-3 and control groups, P < 0.01. Whereas, there was an obviously downward trend in the apoptosis rate of EVs4, compared to other three groups, P < 0.01. Linc-VLDLR and ABCG2 mRNA and protein expression level in Eca109 cells of EVs4 group were significantly higher than that of EVs1-3 and control groups, P < 0.05.

CONCLUSIONS

High expression of Linc-VLDLR and ABCG2 gene in esophageal cancer cells affected the formation of esophageal cancer drug resistance. EVs released by drug-resistant cells were proved that they could upregulate the expression of ABCG2 in esophageal cancer cells and thus regulate the drug resistance of esophageal cancer cells, which was related to the linc-VLDLR carried by EVs.

Induced pluripotent stem cell-derived extracellular vesicles: A novel approach for cell-free regenerative medicine

In recent years, induced pluripotent stem cells (iPSCs) have been considered as a promising approach in the field of regenerative medicine. iPSCs can be generated from patients' somatic cells and possess the potential to differentiate, under proper conditions, into any cell type. However, the clinical application of iPS cells is restricted because of their tumorigenic potential. Recent studies have indicated that stem cells exert their therapeutic benefit via a paracrine mechanism, and extracellular vesicles have been demonstrated that play a critical role in this paracrine mechanism. Due to lower immunogenicity, easier management, and presenting no risk of tumor formation, in recent years, researchers turned attention to exosomes as potential alternatives to whole-cell therapy. Application of exosomes derived from iPSCs and their derived precursor provides a promising approach for personalized regenerative medicine. This study reviews the physiological functions of extracellular vesicles and discusses their potential therapeutic benefit in regenerative medicine.

Biomarkers: paving stones on the road towards the personalized precision medicine for oral squamous cell carcinoma

Traditional therapeutics have encountered a bottleneck caused by diagnosis delay and subjective and unreliable assessment. Biomarkers can overcome this bottleneck and guide us toward personalized precision medicine for oral squamous cell carcinoma. To achieve this, it is important to efficiently and accurately screen out specific biomarkers from among the huge number of molecules. Progress in omics-based high-throughput technology has laid a solid foundation for biomarker discovery. With credible and systemic biomarker models, more precise and personalized diagnosis and assessment would be achieved and patients would be more likely to be cured and have a higher quality of life. However, this is not straightforward owing to the complexity of molecules involved in tumorigenesis. In this context, there is a need to focus on tumor heterogeneity and homogeneity, which are discussed in detail. In this review, we aim to provide an understanding of biomarker discovery and application for precision medicine of oral squamous cell carcinoma, and have a strong belief that biomarker will pave the road toward future precision medicine.

C6 glioma-derived microvesicles stimulate the proliferative and metastatic gene expression of normal astrocytes

The interaction between glioma cells and the surrounding microenvironment plays a key role in tumor invasion and infiltration ability. Recent studies reported the importance of glioma-derived microvesicles in the interaction of the tumor and the surrounding environment. The purpose of this study was to scrutinize the role of glioma-derived microvesicles in the interaction between tumor and normal astrocytes, which are the most abundant non-neoplastic cells in the tumor microenvironment (TME). To this end, we examined the effect of C6 tumor cell-derived microvesicles in the activation of normal rat astrocytes. The results showed that exposing normal astrocytes to C6MVs increase the expression of the glial fibrillary acidic protein (GFAP), and activate normal astrocytes. In addition, incubation of normal astrocytes with C6MVs affects the expression of genes involved in tumor invasion and growth in these cells. Our findings suggest that C6 tumor cells through the secretion of microvesicles (MVs) can alter the phenotype of surrounding astrocytes as well as through the changes in the expression of the genes involved in extracellular matrix remodeling can predispose their invasion and growth.

Transcriptome reprogramming by cancer exosomes: identification of novel molecular targets in matrix and immune modulation

BACKGROUND

Exosomes are extracellular vesicles released by almost all cell types, including cancer cells, into bodily fluids such as saliva, plasma, breast milk, semen, urine, cerebrospinal fluid, amniotic fluid, synovial fluid and sputum. Their key function being intercellular communication with both neighbouring as well as distant cells. Cancer exosomes have been shown to regulate organ-specific metastasis. However, little is known about the functional differences and molecular consequences of normal cells responding to exosomes derived from normal cells compared to those derived from cancer cells.

METHODS

Here, we characterised and compared the transcriptome profiles of primary human normal oral keratinocytes (HNOK) in response to exosomes isolated from either primary HNOK or head and neck squamous cell carcinoma (HNSCC) cell lines.

RESULTS

In recipient HNOK cells, we found that regardless of normal or cancer derived, exosomes altered molecular programmes involved in matrix modulation (MMP9), cytoskeletal remodelling (TUBB6, FEZ1, CCT6A), viral/dsRNA-induced interferon (OAS1, IFI6), anti-inflammatory (TSC22D3), deubiquitin (OTUD1), lipid metabolism and membrane trafficking (BBOX1, LRP11, RAB6A). Interestingly, cancer exosomes, but not normal exosomes, modulated expression of matrix remodelling (EFEMP1, DDK3, SPARC), cell cycle (EEF2K), membrane remodelling (LAMP2, SRPX), differentiation (SPRR2E), apoptosis (CTSC), transcription/translation (KLF6, PUS7). We have also identified CEP55 as a potential cancer exosomal marker.

CONCLUSIONS

In conclusion, both normal and cancer exosomes modulated unique gene expression pathways in normal recipient cells. Cancer cells may exploit exosomes to confer transcriptome reprogramming that leads to cancer-associated pathologies such as angiogenesis, immune evasion/modulation, cell fate alteration and metastasis. Molecular pathways and biomarkers identified in this study may be clinically exploitable for developing novel liquid-biopsy based diagnostics and immunotherapies.

Liquid Biopsy in Oral Cancer

Oral cancer is one of the most prevalent forms of cancer worldwide. Carcinogenesis is a complex process, in which heterogeneity plays an important role in the development and progression of the disease. This review provides an overview of the current biological and clinical significance of circulating tumour cells (CTCs), circulating tumour DNA (ctDNA), and exosomes for diagnosis and prognosis of oral cancer. We highlight the importance of liquid biopsy—using blood and saliva—which represents a potential alternative to solid biopsy for diagnosis and prognosis. Moreover, liquid biomarkers allow for the real-time monitoring of tumour evolution and therapeutic responses, initiating the era of personalized medicine. However, in oral cancer, the impact of liquid biopsies in clinical settings is still limited, requiring further studies to discover the best scenario for its clinical use.

The molecular landscape of head and neck cancer

Head and neck squamous cell carcinomas (HNSCCs) arise in the mucosal linings of the upper aerodigestive tract and are unexpectedly heterogeneous in nature. Classical risk factors are smoking and excessive alcohol consumption, and in recent years, the role of human papillomavirus (HPV) has emerged, particularly in oropharyngeal tumours. HPV-induced oropharyngeal tumours are considered a separate disease entity, which recently has manifested in an adapted prognostic staging system while the results of de-intensified treatment trials are awaited. Carcinogenesis caused by HPV in the mucosal linings of the upper aerodigestive tract remains an enigma, but with some recent observations, a model can be proposed. In 2015, The Cancer Genome Atlas (TCGA) consortium published a comprehensive molecular catalogue on HNSCC. Frequent mutations of novel druggable oncogenes were not demonstrated, but the existence of a subgroup of genetically distinct HPV-negative head and neck tumours with favourable prognoses was confirmed. Tumours can be further subclassified based on genomic profiling. However, the amount of molecular data is currently overwhelming and requires detailed biological interpretation. It also became apparent that HNSCC is a disease characterized by frequent mutations that create neoantigens, indicating that immunotherapies might be effective. In 2016, the first results of immunotherapy trials with immune checkpoint inhibitors were published, and these may be considered as a paradigm shift in head and neck oncology.

The Unforeseen Non-Coding RNAs in Head and Neck Cancer

Previously ignored non-coding RNAs (ncRNAs) have become the subject of many studies. However, there is an imbalance in the amount of consideration that ncRNAs are receiving. Some transcripts such as microRNAs (miRNAs) or small interfering RNAs (siRNAs) have gained much attention, but it is necessary to investigate other “pieces of the RNA puzzle”. These can offer a more complete view over normal and pathological cell behavior. The other ncRNA species are less studied, either due to their recent discovery, such as stable intronic sequence RNA (sisRNA), YRNA, miRNA-offset RNAs (moRNA), telomerase RNA component (TERC), natural antisense transcript (NAT), transcribed ultraconserved regions (T-UCR), and pseudogene transcript, or because they are still largely seen as non-coding transcripts with no relevance to pathogenesis. Moreover, some are still considered housekeeping RNAs, for instance small nucleolar RNAs (snoRNAs) and TERC. Our review summarizes the biogenesis, mechanism of action and potential role of less known ncRNAs in head and neck cancer, with a particular focus on the installment and progress for this particular cancer type.

New Technologies for Analysis of Extracellular Vesicles

Extracellular vesicles (EVs) are diverse, nanoscale membrane vesicles actively released by cells. Similar-sized vesicles can be further classified (e.g., exosomes, microvesicles) based on their biogenesis, size, and biophysical properties. Although initially thought to be cellular debris, and thus under-appreciated, EVs are now increasingly recognized as important vehicles of intercellular communication and circulating biomarkers for disease diagnoses and prognosis. Despite their clinical potential, the lack of sensitive preparatory and analytical technologies for EVs poses a barrier to clinical translation. New analytical platforms including molecular ones are thus actively being developed to address these challenges. Recent advances in the field are expected to have far-reaching impact in both basic and translational studies. This article aims to present a comprehensive and critical overview of emerging analytical technologies for EV detection and their clinical applications.

Extracellular Vesicles: How the External and Internal Environment Can Shape Cell-To-Cell Communication

PURPOSE OF THE REVIEW

To summarize the scientific evidence regarding the effects of environmental exposures on extracellular vesicle (EV) release and their contents. As environmental exposures might influence the aging phenotype in a very strict way, we will also report the role of EVs in the biological aging process.

RECENT FINDINGS

EV research is a new and quickly developing field. With many investigations conducted so far, only a limited number of studies have explored the potential role EVs play in the response and adaptation to environmental stimuli. The investigations available to date have identified several exposures or lifestyle factors able to modify EV trafficking including air pollutants, cigarette smoke, alcohol, obesity, nutrition, physical exercise, and oxidative stress. EVs are a very promising tool, as biological fluids are easily obtainable biological media that, if successful in identifying early alterations induced by the environment and predictive of disease, would be amenable to use for potential future preventive and diagnostic applications.

Biological Functions and Current Advances in Isolation and Detection Strategies for Exosome Nanovesicles

Exosomes are nanoscale (≈30-150 nm) extracellular vesicles of endocytic origin that are shed by most types of cells and circulate in bodily fluids. Exosomes carry a specific composition of proteins, lipids, RNA, and DNA and can work as cargo to transfer this information to recipient cells. Recent studies on exosomes have shown that they play an important role in various biological processes, such as intercellular signaling, coagulation, inflammation, and cellular homeostasis. These functional roles are attributed to their ability to transfer RNA, proteins, enzymes, and lipids, thereby affecting the physiological and pathological conditions in various diseases, including cancer and neurodegenerative, infectious, and autoimmune diseases (e.g., cancer initiation, progression, and metastasis). Due to these unique characteristics, exosomes are considered promising biomarkers for the diagnosis and prognosis of various diseases via noninvasive or minimally invasive procedures. Over the last decade, a plethora of methodologies have been developed for analyzing disease-specific exosomes using optical and nonoptical tools. Here, the major biological functions, significance, and potential role of exosomes as biomarkers and therapeutics are discussed. Furthermore, an overview of the most commonly used techniques for exosome analysis, highlighting the major technical challenges and limitations of existing techniques, is presented.

MicroRNAs Reprogram Tumor Immune Response

Endogenously produced microRNAs (miRNAs) are predicted to regulate the translation of over two-thirds all human gene transcripts. Certain microRNAs regulate expression of genes that are critically involved in both innate and adaptive immune responses. miRNAs have been demonstrated to function as crucial regulators of immune response under both physiological and pathological conditions. Specifically, different miRNAs have been reported to have a role in controlling the development and the functions of tumor-associated immune cells. Immune cells represent a highly attractive target for microRNA gene therapy approaches, as these cells can be isolated, treated, and then reintroduced into patients. In this chapter, we will discuss how recent discoveries on the roles of microRNAs in immune-regulation will advance the field of cancer immunology and immunotherapy.