Heat shock protein 60 levels in tissue and circulating exosomes in human large bowel cancer before and after ablative surgery

Biomarkers in Prostate Cancer Diagnosis: From Current Knowledge to the Role of Metabolomics and Exosomes

Early detection of prostate cancer (PC) is largely carried out using assessment of prostate-specific antigen (PSA) level; yet it cannot reliably discriminate between benign pathologies and clinically significant forms of PC. To overcome the current limitations of PSA, new urinary and serum biomarkers have been developed in recent years. Although several biomarkers have been explored in various scenarios and patient settings, to date, specific guidelines with a high level of evidence on the use of these markers are lacking. Recent advances in metabolomic, genomics, and proteomics have made new potential biomarkers available. A number of studies focused on the characterization of the specific PC metabolic phenotype using different experimental approaches has been recently reported; yet, to date, research on metabolomic application for PC has focused on a small group of metabolites that have been known to be related to the prostate gland. Exosomes are extracellular vesicles that are secreted from all mammalian cells and virtually detected in all bio-fluids, thus allowing their use as tumor biomarkers. Thanks to a general improvement of the technical equipment to analyze exosomes, we are able to obtain reliable quantitative and qualitative information useful for clinical application. Although some pilot clinical investigations have proposed potential PC biomarkers, data are still preliminary and non-conclusive.

Exploiting the HSP60/10 chaperonin system as a chemotherapeutic target for colorectal cancer

Over the past few decades, an increasing variety of molecular chaperones have been investigated for their role in tumorigenesis and as potential chemotherapeutic targets; however, the 60 kDa Heat Shock Protein (HSP60), along with its HSP10 co-chaperone, have received little attention in this regard. In the present study, we investigated two series of our previously developed inhibitors of the bacterial homolog of HSP60/10, called GroEL/ES, for their selective cytotoxicity to cancerous over non-cancerous colorectal cells. We further developed a third "hybrid" series of analogs to identify new candidates with superior properties than the two parent scaffolds. Using a series of well-established HSP60/10 biochemical screens and cell-viability assays, we identified 24 inhibitors (14%) that exhibited > 3-fold selectivity for targeting colorectal cancer over non-cancerous cells. Notably, cell viability EC₅₀ results correlated with the relative expression of HSP60 in the mitochondria, suggesting a potential for this HSP60-targeting chemotherapeutic strategy as emerging evidence indicates that HSP60 is up-regulated in colorectal cancer tumors. Further examination of five lead candidates indicated their ability to inhibit the clonogenicity and migration of colorectal cancer cells. These promising results are the most thorough analysis and first reported instance of HSP60/10 inhibitors being able to selectively target colorectal cancer cells and highlight the potential of the HSP60/10 chaperonin system as a viable chemotherapeutic target.

Molecular Chaperones and Thyroid Cancer

Thyroid cancers are the most common of the endocrine system malignancies and progress must be made in the areas of differential diagnosis and treatment to improve patient management. Advances in the understanding of carcinogenic mechanisms have occurred in various fronts, including studies of the chaperone system (CS). Components of the CS are found to be quantitatively increased or decreased, and some correlations have been established between the quantitative changes and tumor type, prognosis, and response to treatment. These correlations provide the basis for identifying distinctive patterns useful in differential diagnosis and for planning experiments aiming at elucidating the role of the CS in tumorigenesis. Here, we discuss studies of the CS components in various thyroid cancers (TC). The chaperones belonging to the families of the small heat-shock proteins Hsp70 and Hsp90 and the chaperonin of Group I, Hsp60, have been quantified mostly by immunohistochemistry and Western blot in tumor and normal control tissues and in extracellular vesicles. Distinctive differences were revealed between the various thyroid tumor types. The most frequent finding was an increase in the chaperones, which can be attributed to the augmented need for chaperones the tumor cells have because of their accelerated metabolism, growth, and division rate. Thus, chaperones help the tumor cell rather than protect the patient, exemplifying chaperonopathies by mistake or collaborationism. This highlights the need for research on chaperonotherapy, namely the development of means to eliminate/inhibit pathogenic chaperones.

Mining the plasma-proteome associated genes in patients with gastro-esophageal cancers for biomarker discovery

Gastro-esophageal (GE) cancers are one of the major causes of cancer-related death in the world. There is a need for novel biomarkers in the management of GE cancers, to yield predictive response to the available therapies. Our study aims to identify leading genes that are differentially regulated in patients with these cancers. We explored the expression data for those genes whose protein products can be detected in the plasma using the Cancer Genome Atlas to identify leading genes that are differentially regulated in patients with GE cancers. Our work predicted several candidates as potential biomarkers for distinct stages of GE cancers, including previously identified CST1, INHBA, STMN1, whose expression correlated with cancer recurrence, or resistance to adjuvant therapies or surgery. To define the predictive accuracy of these genes as possible biomarkers, we constructed a co-expression network and performed complex network analysis to measure the importance of the genes in terms of a ratio of closeness centrality (RCC). Furthermore, to measure the significance of these differentially regulated genes, we constructed an SVM classifier using machine learning approach and verified these genes by using receiver operator characteristic (ROC) curve as an evaluation metric. The area under the curve measure was > 0.9 for both the overexpressed and downregulated genes suggesting the potential use and reliability of these candidates as biomarkers. In summary, we identified leading differentially expressed genes in GE cancers that can be detected in the plasma proteome. These genes have potential to become diagnostic and therapeutic biomarkers for early detection of cancer, recurrence following surgery and for development of targeted treatment.

Molecular Chaperones in Osteosarcoma: Diagnosis and Therapeutic Issues

Osteosarcoma (OS) is the most common form of primary bone tumor affecting mainly children and young adults. Despite therapeutic progress, the 5-year survival rate is 70%, but it drops drastically to 30% for poor responders to therapies or for patients with metastases. Identifying new therapeutic targets is thus essential. Heat Shock Proteins (HSPs) are the main effectors of Heat Shock Response (HSR), the expression of which is induced by stressors. HSPs are a large family of proteins involved in the folding and maturation of other proteins in order to maintain proteostasis. HSP overexpression is observed in many cancers, including breast, prostate, colorectal, lung, and ovarian, as well as OS. In this article we reviewed the significant role played by HSPs in molecular mechanisms leading to OS development and progression. HSPs are directly involved in OS cell proliferation, apoptosis inhibition, migration, and drug resistance. We focused on HSP27, HSP60, HSP70 and HSP90 and summarized their potential clinical uses in OS as either biomarkers for diagnosis or therapeutic targets. Finally, based on different types of cancer, we consider the advantage of targeting heat shock factor 1 (HSF1), the major transcriptional regulator of HSPs in OS.

The Triad Hsp60-miRNAs-Extracellular Vesicles in Brain Tumors: Assessing Its Components for Understanding Tumorigenesis and Monitoring Patients

Brain tumors have a poor prognosis and progress must be made for developing efficacious treatments, but for this to occur their biology and interaction with the host must be elucidated beyond current knowledge. What has been learned from other tumors may be applied to study brain tumors, for example, the role of Hsp60, miRNAs, and extracellular vesicles (EVs) in the mechanisms of cell proliferation and dissemination, and resistance to immune attack and anticancer drugs. It has been established that Hsp60 increases in cancer cells, in which it occurs not only in the mitochondria but also in the cytosol and plasma-cell membrane and it is released in EVs into the extracellular space and in circulation. There is evidence suggesting that these EVs interact with cells near and far from their original cell and that this interaction has an impact on the functions of the target cell. It is assumed that this crosstalk between cancer and host cells favors carcinogenesis in various ways. We, therefore, propose to study the triad Hsp60-related miRNAs-EVs in brain tumors and have standardized methods for the purpose. These revealed that EVs with Hsp60 and related miRNAs increase in patients’ blood in a manner that reflects disease status. The means are now available to monitor brain tumor patients by measuring the triad and to dissect its effects on target cells in vitro, and in experimental models in vivo.

Exosomes: A new frontier under the spotlight for diagnosis and treatment of gastrointestinal diseases

Exosomes are small plasma membrane-bound multivesicular bodies ranging in size from 20-100 nm. Exosomes are degraded fragments of mRNA, microRNA, and enriched in proteins, lipids, and nucleic acid. They are produced in the endosomes of most eukaryotic cells and once secreted, exosomes are involved in cell to cell communication and remodeling of the matrix in the extracellular compartment. Exosome biogenesis plays a crucial role in cellular development, inflammation, immunity, hemostasis, carcinogenesis, and degeneration. Due to their unique biochemical and biophysical properties, exosomes serve a variety of functions including biomarkers of diagnostic and prognostic significance. Besides, there is an increasing level of evidence to expand our understanding of the exosomes as novel therapeutic agents. Inflammatory bowel disease (IBD) such as Crohn's disease and ulcerative colitis, hepatic fibrosis, and gastrointestinal malignancies such as colorectal cancer are the potential avenues where exosomes can be applied as cell therapy and immunotherapy and have shown promising results in several in-vitro and animal models. The purpose of this review article is to highlight the emerging role of exosomes as the diagnostic and therapeutic tool in various diseases involving the gastrointestinal tract like IBD, hepatocellular carcinoma, and colon cancer. A thorough literature search was performed on databases such as PubMed, Ovid Medline, and EMBASE to achieve the objectives of this review article.

The tumorigenic and therapeutic functions of exosomes in colorectal cancer: Opportunity and challenges

Most cells release extracellular vesicles (EVs) mediating intercellular communication via transferring various biomolecules including proteins, nucleic acids, and lipids. A subset of EVs is exosomes that promote tumorigenesis. Different tumour cells such as colorectal cancer (CRC) cells produce exosomes that participate in the progression of CRC. Exosomes cargo including proteins and miRNAs not only support proliferation and metastasis of tumour cells but also mediate chemoresistance, immunomodulation and angiogenesis. In addition, as exosomes are present in most body fluids, they can hold the great capacity for clinical usage in early diagnosis and prognosis of CRC. Exosomes from CRC (CRC-Exo) differentially contain proteins and miRNAs that make them a promising candidate for CRC diagnosis by a simple liquid-biopsy. Despite hopeful results, some challanges about exosomes terminology and definition remains to be clarified in further experiments. In addition, there are little clinical trials regarding the application of exosomes in CRC treatment, therefore additional studies are essential focusing on exosome biology and translation of preclinical findings into the clinic. The present study discusses the key role of exosomes in CRC progression and diagnosis. Furthermore, it describes the opportunity and challenges associated with using exosomes as tumour markers.

Extracellular heat shock proteins and cancer: New perspectives

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High expression of extracellular heat shock proteins (HSPs) indicates highly aggressive tumors.

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HSP profiling of extracellular vesicles (EVs) derived from various biological fluids and released by immune cells may open new perspectives for an identification of diagnostic, prognostic and predictive biomarkers of cancer.

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Identification of specific microRNAs targeting HSPs in EVs may be a promising strategy for the discovery of novel biomarkers of cancer.

Heat shock proteins (HSPs) are a large family of molecular chaperones aberrantly expressed in cancer. The expression of HSPs in tumor cells has been shown to be implicated in the regulation of apoptosis, immune responses, angiogenesis and metastasis. Given that extracellular vesicles (EVs) can serve as potential source for the discovery of clinically useful biomarkers and therapeutic targets, it is of particular interest to study proteomic profiling of HSPs in EVs derived from various biological fluids of cancer patients. Furthermore, a divergent expression of circulating microRNAs (miRNAs) in patient samples has opened new opportunities in exploiting miRNAs as diagnostic tools. Herein, we address the current literature on the expression of extracellular HSPs with particular interest in HSPs in EVs derived from various biological fluids of cancer patients and different types of immune cells as promising targets for identification of clinical biomarkers of cancer. We also discuss the emerging role of miRNAs in HSP regulation for the discovery of blood-based biomarkers of cancer. We outline the importance of understanding relationships between various HSP networks and co-chaperones and propose the model for identification of HSP signatures in cancer. Elucidating the role of HSPs in EVs from the proteomic and miRNAs perspectives may provide new opportunities for the discovery of novel biomarkers of cancer.

A signal peptide derived from Hsp60 induces protective cytotoxic T lymphocyte immunity against lymphoid malignancies independently of TAP and classical MHC-I

Hsp60sp, a signal peptide derived from the leader sequence of heat shock protein 60 kDa (Hsp60), is a Qa-1/HLA-E-binding peptide. We previously showed that Hsp60sp-specific CD8⁺ T cells are involved in the immunoregulation of autoimmune diseases by controlling the response of self-reactive lymphocytes. Here, we report that Hsp60sp-specific CD8⁺ T cells killed malignant lymphocytes in vitro independently of transporter associated with antigen processing (TAP) and classical MHC-I expression. Induction of this cytotoxic T lymphocyte (CTL) response in vivo, either by adoptive transfer of in vitro-amplified CTLs or peptide-loaded dendritic cell immunization, resulted in effective control of lymphoid tumors, including TAP- or classical MHC-I-deficient cells. Hsp60sp-specific immune activation combined with programmed cell death protein 1 (PD-1) blocking synergistically restrained mouse lymphoma development. Importantly, Hsp60sp-specific CD8⁺ T cells did not negatively affect normal tissues and cells. Our data suggest that Hsp60sp-based immunotherapy is an inviting strategy to control lymphoid malignancies.

Advances in the discovery of exosome inhibitors in cancer

Exosomes are small membrane vesicles released by most eukaryotic cells. They are considered to play an essential role in cell-to-cell communication, and It is also found that they serve as functional mediators in many severe diseases, including progression of various types of cancers. Inhibition of exosome release may slow the progression of some cancers; thus, exosome has been an attractive target for cancer treatment. Over the years, considerable efforts have been made to discover novel, highly potent and excellently selective exosome inhibitors. Most of these inhibitors are derived from synthetic compounds, some of which are currently existed drugs and found to have the potential to inhibit exosome release. In this review, we briefly discussed the development of exosome inhibitors that are currently discovered and provided guidance for the future development of inhibitors.

EVs as Potential New Therapeutic Tool/Target in Gastrointestinal Cancer and HCC

For more than a decade, extracellular vesicles (EVs) have been in focus of science. Once thought to be an efficient way to eliminate undesirable cell content, EVs are now well-accepted as being an important alternative to cytokines and chemokines in cell-to-cell communication route. With their cargos, mainly consisting of functional proteins, lipids and nucleic acids, they can activate signalling cascades and thus change the phenotype of recipient cells at local and systemic levels. Their substantial role as modulators of various physiological and pathological processes is acknowledged. Importantly, more and more evidence arises that EVs play a pivotal role in many stages of carcinogenesis. Via EV-mediated communication, tumour cells can manipulate cells from host immune system or from the tumour microenvironment, and, ultimately, they promote tumour progression and modulate host immunity towards tumour's favour. Additionally, the role of EVs in modulating resistance to pharmacological and radiological therapy of many cancer types has become evident lately. Our understanding of EV biology and their role in cancer promotion and drug resistance has evolved considerably in recent years. In this review, we specifically discuss the current knowledge on the association between EVs and gastrointestinal (GI) and liver cancers, including their potential for diagnosis and treatment.

Brain Tumor-Derived Extracellular Vesicles as Carriers of Disease Markers: Molecular Chaperones and MicroRNAs

Primary and metastatic brain tumors are usually serious conditions with poor prognosis, which reveal the urgent need of developing rapid diagnostic tools and efficacious treatments. To achieve these objectives, progress must be made in the understanding of brain tumor biology, for example, how they resist natural defenses and therapeutic intervention. One resistance mechanism involves extracellular vesicles that are released by tumors to meet target cells nearby or distant via circulation and reprogram them by introducing their cargo. This consists of different molecules among which are microRNAs (miRNAs) and molecular chaperones, the focus of this article. miRNAs modify target cells in the immune system to avoid antitumor reaction and chaperones are key survival molecules for the tumor cell. Extracellular vesicles cargo reflects the composition and metabolism of the original tumor cell; therefore, it is a source of markers, including the miRNAs and chaperones discussed in this article, with potential diagnostic and prognostic value. This and their relatively easy availability by minimally invasive procedures (e.g., drawing venous blood) illustrate the potential of extracellular vesicles as useful materials to manage brain tumor patients. Furthermore, understanding extracellular vesicles circulation and interaction with target cells will provide the basis for using this vesicle for delivering therapeutic compounds to selected tumor cells.

Exosomes: A Source for New and Old Biomarkers in Cancer

Clinical oncology needs reliable tumor biomarkers to allow a follow-up of tumor patients who do not necessarily need invasive approaches. To date, the existing biomarkers are not sufficiently reliable, and many of them have generated more problems than facilitating the commitment of clinical oncologists. Over the last decades, a broad family of extracellular vesicles, with size ranging between micro to nano, has been raised as a new hope for potential sources of new tumor biomarkers. However, while knowledge in the field is increasing, we do not currently have definitive information allowing a clinical use of extracellular vesicles in cancer clinics. Recent evidence provides new perspective in clinical oncology, based on data showing that circulating nanovesicles called exosomes may represent a valuable source of tumor biomarkers. In this review, we discuss the existing clinical data supporting a key role of exosomes as a source of tumor biomarkers, including proteins and miRNAs, but also discuss the importance of the expression of known tumor biomarkers when expressed on exosomes.

Extracellular Chaperones as Novel Biomarkers of Overall Cancer Progression and Efficacy of Anticancer Therapy

Exosomal heat shock proteins (Hsps) are involved in intercellular communication both in physiological and pathological conditions. They play a role in key processes of carcinogenesis including immune system regulation, cell differentiation, vascular homeostasis and metastasis formation. Thus, exosomal Hsps are emerging biomarkers of malignancies and possible therapeutic targets. Adolescents and young adults (AYAs) are patients aged 15–39 years. This age group, placed between pediatric and adult oncology, pose a particular challenge for cancer management. New biomarkers of cancer growth and progression as well as prognostic factors are desperately needed in AYAs. In this review, we attempted to summarize the current knowledge on the role of exosomal Hsps in selected solid tumors characteristic for the AYA population and/or associated with poor prognosis in this age group. These included malignant melanoma, brain tumors, and breast, colorectal, thyroid, hepatocellular, lung and gynecological tract carcinomas. The studies on exosomal Hsps in these tumors are limited; however; some have provided promising results. Although further research is needed, there is potential for future clinical applications of exosomal Hsps in AYA cancers, both as novel biomarkers of disease presence, progression or relapse, or as therapeutic targets or tools for drug delivery.

Extracellular Vesicles-Based Drug Delivery Systems: A New Challenge and the Exemplum of Malignant Pleural Mesothelioma

Research for the most selective drug delivery to tumors represents a fascinating key target in science. Alongside the artificial delivery systems identified in the last decades (e.g., liposomes), a family of natural extracellular vesicles (EVs) has gained increasing focus for their potential use in delivering anticancer compounds. EVs are released by all cell types to mediate cell-to-cell communication both at the paracrine and the systemic levels, suggesting a role for them as an ideal nano-delivery system. Malignant pleural mesothelioma (MPM) stands out among currently untreatable tumors, also due to the difficulties in achieving an early diagnosis. Thus, early diagnosis and treatment of MPM are both unmet clinical needs. This review looks at indirect and direct evidence that EVs may represent both a new tool for allowing an early diagnosis of MPM and a potential new delivery system for more efficient therapeutic strategies. Since MPM is a relatively rare malignant tumor and preclinical MPM models developed to date are very few and not reliable, this review will report data obtained in other tumor types, suggesting the potential use of EVs in mesothelioma patients as well.

Does SARS-CoV-2 Trigger Stress-InducedAutoimmunity by Molecular Mimicry? A Hypothesis

Viruses can generate molecular mimicry phenomena within their hosts. Why should severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) not be considered one of these? Information in this short review suggests that it might be so and, thus, encourages research aiming at testing this possibility. We propose, as a working hypothesis, that the virus induces antibodies and that some of them crossreact with host’s antigens, thus eliciting autoimmune phenomena with devasting consequences in various tissues and organs. If confirmed, by in vitro and in vivo tests, this could drive researchers to find effective treatments against the virus.

Exosomes as Actively Targeted Nanocarriers for Cancer Therapy

In recent years, it has been found that exosomes can be used as nanocarriers, which can be used in the treatment of tumors by carrying contents. The exosomes are derived from the secretion of the organism's own cells and are characterized by a phospholipid bilayer structure and a small particle size. These characteristics guarantee that the exosomes can carry a wide range of tumor drugs, deliver the drug to the cancer, and reduce or eliminate the tumor drug band. The toxic side effects were significantly eliminated; meanwhile, the therapeutic effects of the drug on the tumor were remarkably improved. This paper reviewed the strategies and drugs presented by different scholars for the treatment of tumors based on the drugs carried by exosomes.

Hsp60 Post-translational Modifications: Functional and Pathological Consequences

Hsp60 is a chaperone belonging to the Chaperonins of Group I and typically functions inside mitochondria in which, together with the co-chaperonin Hsp10, maintains protein homeostasis. In addition to this canonical role, Hsp60 plays many others beyond the mitochondria, for instance in the cytosol, plasma-cell membrane, extracellular space, and body fluids. These non-canonical functions include participation in inflammation, autoimmunity, carcinogenesis, cell replication, and other cellular events in health and disease. Thus, Hsp60 is a multifaceted molecule with a wide range of cellular and tissue locations and functions, which is noteworthy because there is only one hsp60 gene. The question is by what mechanism this protein can become multifaceted. Likely, one factor contributing to this diversity is post-translational modification (PTM). The amino acid sequence of Hsp60 contains many potential phosphorylation sites, and other PTMs are possible such as O-GlcNAcylation, nitration, acetylation, S-nitrosylation, citrullination, oxidation, and ubiquitination. The effect of some of these PTMs on Hsp60 functions have been examined, for instance phosphorylation has been implicated in sperm capacitation, docking of H2B and microtubule-associated proteins, mitochondrial dysfunction, tumor invasiveness, and delay or facilitation of apoptosis. Nitration was found to affect the stability of the mitochondrial permeability transition pore, to inhibit folding ability, and to perturb insulin secretion. Hyperacetylation was associated with mitochondrial failure; S-nitrosylation has an impact on mitochondrial stability and endothelial integrity; citrullination can be pro-apoptotic; oxidation has a role in the response to cellular injury and in cell migration; and ubiquitination regulates interaction with the ubiquitin-proteasome system. Future research ought to determine which PTM causes which variations in the Hsp60 molecular properties and functions, and which of them are pathogenic, causing chaperonopathies. This is an important topic considering the number of acquired Hsp60 chaperonopathies already cataloged, many of which are serious diseases without efficacious treatment.

Role of HSP60/HSP10 in Lung Cancer: Simple Biomarkers or Leading Actors?

Cancers are one of the major challenges faced by modern medicine both because of their impact in terms of the amount of cases and of the ineffectiveness of therapies used today. A concrete support to the fight against them can be found in the analysis and understanding of the molecular mechanisms involving molecular chaperones. In particular, HSP60 and HSP10 seem to play an important role in carcinogenesis, supporting tumours in their proliferation, survival, and metastasis. Efforts must be directed toward finding ways to eliminate or block this "mistaken" chaperone. Therefore, the scientific community must develop therapeutic strategies that consider HSP60 and HSP10 as the possible target of an anti-tumoural treatment and not only as diagnostic biomarkers, since they contribute to the evolution of pre-cancerous respiratory pathologies in lung tumours. HSP60 acts at the mitochondrial, cytoplasmic, and extracellular levels in the development of cancer pathologies. The molecular mechanisms in which these chaperones are involved concern cell survival, the restoration of a condition of absence of replicative senescence, the promotion of pro-inflammatory environments, and an increase in the ability to form metastases. In this review, we will also present examples of interactions between HSP60 and HSP10 and different molecules and ways to exploit this knowledge in anticancer therapies for lung tumours. In order to improve not only chances for an earlier diagnosis but also treatments for patients suffering from this type of disease, chaperones must be considered as key agents in carcinogenesis and primary targets in therapeutics.

Curcumin Affects HSP60 Folding Activity and Levels in Neuroblastoma Cells

The fundamental challenge in fighting cancer is the development of protective agents able to interfere with the classical pathways of malignant transformation, such as extracellular matrix remodeling, epithelial–mesenchymal transition and, alteration of protein homeostasis. In the tumors of the brain, proteotoxic stress represents one of the main triggering agents for cell transformation. Curcumin is a natural compound with anti-inflammatory and anti-cancer properties with promising potential for the development of therapeutic drugs for the treatment of cancer as well as neurodegenerative diseases. Among the mediators of cancer development, HSP60 is a key factor for the maintenance of protein homeostasis and cell survival. High HSP60 levels were correlated, in particular, with cancer development and progression, and for this reason, we investigated the ability of curcumin to affect HSP60 expression, localization, and post-translational modifications using a neuroblastoma cell line. We have also looked at the ability of curcumin to interfere with the HSP60/HSP10 folding machinery. The cells were treated with 6, 12.5, and 25 µM of curcumin for 24 h, and the flow cytometry analysis showed that the compound induced apoptosis in a dose-dependent manner with a higher percentage of apoptotic cells at 25 µM. This dose of curcumin-induced a decrease in HSP60 protein levels and an upregulation of HSP60 mRNA expression. Moreover, 25 µM of curcumin reduced HSP60 ubiquitination and nitration, and the chaperonin levels were higher in the culture media compared with the untreated cells. Furthermore, curcumin at the same dose was able to favor HSP60 folding activity. The reduction of HSP60 levels, together with the increase in its folding activity and the secretion in the media led to the supposition that curcumin might interfere with cancer progression with a protective mechanism involving the chaperonin.

Immunocapture-based ELISA to characterize and quantify exosomes in both cell culture supernatants and body fluids

The immunocapture-based ELISA for extracellular vesicles (EVs)/exosomes, originally described in 2009 by Logozzi and colleagues, allows to capture, detect, characterize and quantify extracellular vesicles in both human body fluids and cell culture supernatants. It is based on the use of two antibodies directed one against a typical exosomal housekeeping protein and the second against either another exosomal housekeeping protein or a potential disease marker: the first antibody is used for the capture of exosomes, the second for the quantification and characterization of the captured vesicles. In fact, with this method it is possible both to characterize and count exosomes and to detect the presence of disease, including tumor, biomarkers. This needs of course to preliminary obtain an EVs purification from the clinical sample; the most agreed method to get to an EVs purification is the repeated rounds of ultracentrifugation, that, while far to be perfect, is the methodological approach allowing to not exclude EVs subpopulation from the separation procedure and to analyze a full range of EVs from both qualitative and quantitative point of view. The immunocapture-based approach has proven to be highly useful in screening, diagnosis and prognosis of tumors, in plasma samples. One amazing information provided by this method is that cancer patients have always significantly higher levels of EVs, in particular of exosomes, independently from the histological nature of the tumor. One microenvironmental factor that is fully involved in the increased exosome release by tumors is the extracellular acidity. However, few pre-clinical data suggest that plasmatic levels of exosomes may correlate with the tumor mass. Some recent clinical reports suggest also that circulating exosomes represent the real delivery system for some known tumor markers that are presently on trial (e.g., PSA). Here we review the pros and cons of the immunocapture-based technique in quantitative and qualitative evaluation of EVs in both health and disease.

Hsp60 and IL-8 axis promotes apoptosis resistance in cancer

Background

Interleukin-8 (IL-8) and heat shock protein 60 (Hsp60) play crucial roles in cell survival and maintenance of cellular homoeostasis. However, cross talks between these two proteins are not defined.

Methods

IL-8 expression in tumour tissue sections was analysed by immunohistochemistry. IL-8 expression and release in cancer cells was quantified using enzyme-linked immunosorbent assay (ELISA). Apoptosis was quantified using caspase activity and Annexin-V/PI staining.

Results

We observed IL-8 release from cancer cells in response to histone deacetylase inhibitor, apicidin (Api), and non-competitive inhibitor of the sarco/endoplasmic reticulum Ca²⁺ ATPase, thapsigargin (TG). IL-8 release was increased upon TG-treatment. TG-induced IL-8 expression was reduced in the presence of Api in Bax-dependent manner. Increased apoptosis was associated with decreased IL-8 expression in response to combined treatment of TG and Api. TG and Api combination induced caspase-8 and caspase-9 dependent apoptosis. Hsp60 knockdown abrogated IL-8 expression induced by Api, TG, and their combination. The level of TGF-β, an upstream regulator of IL-8, was decreased upon Hsp60-silencing. Knocking down Hsp60 decreased IL-8 expression and its release in prostate cancer cell xenograft tumours in SCID mice.

Conclusion

This study describes the underlying mechanism associated with apoptosis resistance mediated via Hsp60-IL-8 axis in cancer.

The Functions and Therapeutic Potential of Heat Shock Proteins in Inflammatory Bowel Disease-An Update

Inflammatory bowel disease (IBD) is a multifactorial human intestinal disease that arises from numerous, yet incompletely defined, factors. Two main forms, Crohn's disease (CD) and ulcerative colitis (UC), lead to a chronic pathological form. Heat shock proteins (HSPs) are stress-responsive molecules involved in various pathophysiological processes. Several lines of evidence link the expression of HSPs to the development and prognosis of IBD. HSP90, HSP70 and HSP60 have been reported to contribute to IBD in different aspects. Moreover, induction and/or targeted inhibition of specific HSPs have been suggested to ameliorate the disease consequences. In the present review, we shed the light on the role of HSPs in IBD and their targeting to prevent further disease progression.

Alcohol Exposure Impacts the Composition of HeLa-Derived Extracellular Vesicles

Extracellular vesicles are nanosized vesicles that are under intense investigation for their role in intercellular communication. Extracellular vesicles have begun to be examined for their role in disease protection and their role as disease biomarkers and/or vaccine agents. The goal of this study was to investigate the effects of alcohol exposure on the biogenesis and composition of extracellular vesicles derived from the cervical cancer line, HeLa. The HeLa cells were cultured in exosome-free media and were either mock-treated (control) or treated with 50 mM or 100 mM of alcohol for 24 h and 48 h. Our results demonstrated that alcohol significantly impacts HeLa cell viability and exosome biogenesis/composition. Importantly, our studies demonstrate the critical role of alcohol on HeLa cells, as well as HeLa-derived extracellular vesicle biogenesis and composition. Specifically, these results indicate that alcohol alters extracellular vesicles’ packaging of heat shock proteins and apoptotic proteins. Extracellular vesicles serve as communicators for HeLa cells, as well as biomarkers for the initiation and progression of disease.

Common molecular markers between circulating tumor cells and blood exosomes in colorectal cancer: a systematic and analytical review

Nearly half of patients with colorectal cancer (CRC), the third leading cause of cancer deaths worldwide, are diagnosed in the late stages of the disease. Appropriate treatment is not applied in a timely manner and nearly 90% of the patients who experience metastasis ultimately die. Timely detection of CRC can increase the five-year survival rate of patients. Existing histopathological and molecular classifications are insufficient for prediction of metastasis, which limits approaches to treatment. Detection of reliable cancer-related biomarkers can improve early diagnosis, prognosis, and treatment response prediction and recurrence risk. Circulating tumor cells (CTCs) and exosomes in peripheral blood can be used in a liquid biopsy to assess the status of a tumor. Exosomes are abundant and available in all fluids of the body, have a high half-life and are released by most cells. Tumor-derived exosomes are released from primary tumors or CTCs with selective cargo that represents the overall tumor. The current systematic review highlights new trends and approaches in the detection of CRC biomarkers to determine tumor signatures using CTC and exosomes. When these are combined, they could be used to guide molecular pathology and can revolutionize detection tools. Relevant observational studies published until July 24, 2019 which evaluated the expression of tumor markers in CTCs and exosomes were searched in PubMed, Scopus, Embase, and ISI Web of Science databases. The extracted biomarkers were analyzed using String and EnrichR tools.

Immunomorphological Pattern of Molecular Chaperones in Normal and Pathological Thyroid Tissues and Circulating Exosomes: Potential Use in Clinics

The thyroid is a major component of the endocrine system and its pathology can cause serious diseases, e.g., papillary carcinoma (PC). However, the carcinogenic mechanisms are poorly understood and clinical useful biomarkers are scarce. Therefore, we determined if there are quantitative patterns of molecular chaperones in the tumor tissue and circulating exosomes that may be useful in diagnosis and provide clues on their participation in carcinogenesis. Hsp27, Hsp60, Hsp70, and Hsp90 were quantified by immunohistochemistry in PC, benign goiter (BG), and normal peritumoral tissue (PT). The same chaperones were assessed in plasma exosomes from PC and BG patients before and after ablative surgery, using Western blotting. Hsp27, Hsp60, and Hsp90 were increased in PC in comparison with PT and BG but no differences were found for Hsp70. Similarly, exosomal levels of Hsp27, Hsp60, and Hsp90 were higher in PC than in BG, and those in PC were higher before ablative surgery than after it. Hsp27, Hsp60, and Hsp90 show distinctive quantitative patterns in thyroid tissue and circulating exosomes in PC as compared with BG, suggesting some implication in the carcinogenesis of these chaperones and indicating their potential as biomarkers for clinical applications.

Heat Shock Proteins Are Essential Components in Transformation and Tumor Progression: Cancer Cell Intrinsic Pathways and Beyond

Heat shock protein (HSP) synthesis is switched on in a remarkably wide range of tumor cells, in both experimental animal systems and in human cancer, in which these proteins accumulate in high levels. In each case, elevated HSP concentrations bode ill for the patient, and are associated with a poor outlook in terms of survival in most cancer types. The significance of elevated HSPs is underpinned by their essential roles in mediating tumor cell intrinsic traits such as unscheduled cell division, escape from programmed cell death and senescence, de novo angiogenesis, and increased invasion and metastasis. An increased HSP expression thus seems essential for tumorigenesis. Perhaps of equal significance is the pronounced interplay between cancer cells and the tumor milieu, with essential roles for intracellular HSPs in the properties of the stromal cells, and their roles in programming malignant cells and in the release of HSPs from cancer cells to influence the behavior of the adjacent tumor and infiltrating the normal cells. These findings of a triple role for elevated HSP expression in tumorigenesis strongly support the targeting of HSPs in cancer, especially given the role of such stress proteins in resistance to conventional therapies.

Bortezomib promotes apoptosis of multiple myeloma cells by regulating HSP27

The aim of the present study was to investigate the effect of bortezomib on heat shock protein 27 (HSP27) in multiple myeloma (MM) and provide a potential new target for clinical treatment. Peripheral blood was collected from 50 normal subjects and 50 patients with newly diagnosed MM and the expression of HSP27 was detected by ELISA. The changes of HSP27 after conventional vincristine, doxorubicin and dexamethasone (VAD) chemotherapy, and bortezomib plus VAD were compared. The effect of bortezomib on U266 cell proliferation and apoptosis was detected using a Cell Counting Kit‑8 assay and Annexin V‑FITC/propidium iodide double staining with flow cytometry. The content of HSP27 following bortezomib treatment was determined by ELISA. Western blot analysis and reverse transcription‑quantitative PCR were used to detect the mRNA and protein expression of HSP27, Bax and Bcl‑2. HSP27 expression was increased in patients with MM compared with healthy control subjects, and the expression was increased as the cancer progressed (P<0.05). Compared with the VAD chemotherapy group, the bortezomib plus VAD chemotherapy regimen significantly inhibited the expression of HSP27 (P<0.05), and the content of HSP27 was decreased in patients in which treatment was effective compared to those patients that exhibited disease progression (P<0.05). The efficacy of the treatment regimes was not associated with age or gender. Compared with the control group, bortezomib or OGX‑427 (HSP27 inhibitor) treatment inhibited U266 cell proliferation, promoted U266 cell apoptosis (P<0.05) and significantly decreased HSP27 expression (P<0.05). Furthermore, the expression of HSP27 and Bcl‑2 was significantly decreased, while the expression of Bax was increased by bortezomib and OGX‑427 (P<0.05). There was no significant difference between the bortezomib and OGX‑427 group in the in vitro analysis. HSP27 was positively correlated with Bcl‑2 expression and negatively correlated with Bax expression in U266 cells. In conclusion, bortezomib promotes the apoptosis of MM cells, potentially by downregulating the expression of HSP27, providing a potential novel target for the clinical treatment of multiple myeloma.

Personalized medicine: From diagnostic to adaptive

Personalized therapy has made great strides but suffers from the lack of companion diagnostics. With the dawn of extracellular vesicle (EV) based liquid biopsies fast approaching, this article proposes a novel approach to cancer treatment – adaptive therapy. Already being implemented in the field of radiation oncology, adaptive radiation therapy utilizes cutting-edge imaging techniques as a viable means to monitor a patient's tumor throughout the entire treatment cycle by adapting the dosage and alignment to match the dynamic tumor. Through an EV liquid biopsy, medical oncologists will also soon have the means to continuously monitor a patient's tumor as it changes over time. With this information, physicians will be able to “adapt” pre-planned therapies concurrently with the fluctuating tumor environment, thus creating a more precise personalized medicine. In this article, a theory for adaptive medicine and the current state of the field with an outlook on future challenges are discussed.

Exosomes, new biomarkers in early cancer detection

Exosomes are endosomal-derived vesicles, playing a major role in cell-to-cell communication. Multiple cells secret these vesicles to induce and inhibit different cellular and molecular pathways. Cancer-derived exosomes have been shown to affect development of cancer in different stages and contribute to the recruitment and reprogramming of both proximal and distal tissues. The growing interest in defining the clinical relevance of these nano-sized particles in cancers, has led to the identification of either tissue- or disease-specific exosomal contents, such as nucleic acids, proteins and lipids as a source of new biomarkers which propose the diagnostic potentials of exosomes in early detection of cancers. In this review, we have discussed some aspects of exosomes including their contents, applications and isolation techniques in the field of early cancer detection. Although, exosomes are considered as ideal biomarkers in cancer diagnosis, due to their unique characteristics, there is still a long way in the development of exosome-based assays.

Extracellular Vesicle-Mediated Cell⁻Cell Communication in the Nervous System: Focus on Neurological Diseases

Extracellular vesicles (EVs), including exosomes, are membranous particles released by cells into the extracellular space. They are involved in cell differentiation, tissue homeostasis, and organ remodelling in virtually all tissues, including the central nervous system (CNS). They are secreted by a range of cell types and via blood reaching other cells whose functioning they can modify because they transport and deliver active molecules, such as proteins of various types and functions, lipids, DNA, and miRNAs. Since they are relatively easy to isolate, exosomes can be characterized, and their composition elucidated and manipulated by bioengineering techniques. Consequently, exosomes appear as promising theranostics elements, applicable to accurately diagnosing pathological conditions, and assessing prognosis and response to treatment in a variety of disorders. Likewise, the characteristics and manageability of exosomes make them potential candidates for delivering selected molecules, e.g., therapeutic drugs, to specific target tissues. All these possible applications are pertinent to research in neurophysiology, as well as to the study of neurological disorders, including CNS tumors, and autoimmune and neurodegenerative diseases. In this brief review, we discuss what is known about the role and potential future applications of exosomes in the nervous system and its diseases, focusing on cell–cell communication in physiology and pathology.

On the Choice of the Extracellular Vesicles for Therapeutic Purposes

Extracellular vesicles (EVs) are lipid membrane vesicles released by all human cells and are widely recognized to be involved in many cellular processes, both in physiological and pathological conditions. They are mediators of cell-cell communication, at both paracrine and systemic levels, and therefore they are active players in cell differentiation, tissue homeostasis, and organ remodeling. Due to their ability to serve as a cargo for proteins, lipids, and nucleic acids, which often reflects the cellular source, they should be considered the future of the natural nanodelivery of bio-compounds. To date, natural nanovesicles, such as exosomes, have been shown to represent a source of disease biomarkers and have high potential benefits in regenerative medicine. Indeed, they deliver both chemical and bio-molecules in a way that within exosomes drugs are more effective that in their exosome-free form. Thus, to date, we know that exosomes are shuttle disease biomarkers and probably the most effective way to deliver therapeutic molecules within target cells. However, we do not know exactly which exosomes may be used in therapy in avoiding side effects as well. In regenerative medicine, it will be ideal to use autologous exosomes, but it seems not ideal to use plasma-derived exosomes, as they may contain potentially dangerous molecules. Here, we want to present and discuss a contradictory relatively unmet issue that is the lack of a general agreement on the choice for the source of extracellular vesicles for therapeutic use.

Hsp60 as a Novel Target in IBD Management: A Prospect

Inflammatory bowel disease (IBD) encompasses various pathological conditions similar but distinct that share a multifactorial etiology, including involvement of the intestinal barrier function, the immune system, and intestinal microorganisms. Hsp60 is a chaperonin component of the chaperoning system, present in all cells and tissues, including the intestine. It plays important roles in cell physiology outside and inside mitochondria, its canonical place of residence. However, Hsp60 can also be pathogenic in many conditions, the Hsp60 chaperonopathies, possibly including IBD. The various clinico-pathological types of IBD have a complicated mix of causative factors, among which Hsp60 can be considered a putatively important driver of events and could play an etiopathogenic role. This possibility is discussed in this review. We also indicate that Hsp60 can be a biomarker useful in disease diagnosing and monitoring and, if found active in pathogenesis, should become a target for developing new therapies. The latter are particularly needed to alleviate patient suffering and to prevent complications, including colon cancer.

Exosomal Chaperones and miRNAs in Gliomagenesis: State-of-Art and Theranostics Perspectives

Gliomas have poor prognosis no matter the treatment applied, remaining an unmet clinical need. As background for a substantial change in this situation, this review will focus on the following points: (i) the steady progress in establishing the role of molecular chaperones in carcinogenesis; (ii) the recent advances in the knowledge of miRNAs in regulating gene expression, including genes involved in carcinogenesis and genes encoding chaperones; and (iii) the findings about exosomes and their cargo released by tumor cells. We would like to trigger a discussion about the involvement of exosomal chaperones and miRNAs in gliomagenesis. Chaperones may be either targets for therapy, due to their tumor-promoting activity, or therapeutic agents, due to their antitumor growth activity. Thus, chaperones may well represent a Janus-faced approach against tumors. This review focuses on extracellular chaperones as part of exosomes' cargo, because of their potential as a new tool for the diagnosis and management of gliomas. Moreover, since exosomes transport chaperones and miRNAs (the latter possibly related to chaperone gene expression in the recipient cell), and probably deliver their cargo in the recipient cells, a new area of investigation is now open, which is bound to generate significant advances in the understanding and treatment of gliomas.

Heat Shock Proteins in Alzheimer's Disease: Role and Targeting

Among diseases whose cure is still far from being discovered, Alzheimer’s disease (AD) has been recognized as a crucial medical and social problem. A major issue in AD research is represented by the complexity of involved biochemical pathways, including the nature of protein misfolding, which results in the production of toxic species. Considering the involvement of (mis)folding processes in AD aetiology, targeting molecular chaperones represents a promising therapeutic perspective. This review analyses the connection between AD and molecular chaperones, with particular attention toward the most important heat shock proteins (HSPs) as representative components of the human chaperome: Hsp60, Hsp70 and Hsp90. The role of these proteins in AD is highlighted from a biological point of view. Pharmacological targeting of such HSPs with inhibitors or regulators is also discussed.

Chaperonology: The Third Eye on Brain Gliomas

The European Organization for Research and Treatment of Cancer/National Cancer Institute of Canada Phase III trial has validated as a current regimen for high-grade gliomas (HGG) a maximal safe surgical resection followed by radiotherapy with concurrent temozolamide. However, it is essential to balance maximal tumor resection with preservation of the patient&rsquo;s neurological functions. Important developments in the fields of pre-operative and intra-operative neuro-imaging and neuro-monitoring have ameliorated the survival rate and the quality of life for patients affected by HGG. Moreover, even though the natural history remains extremely poor, advancement in the molecular and genetic fields have opened up new potential frontiers in the management of this devastating brain disease. In this review, we aim to present a comprehensive account of the main current pre-operative, intra-operative and molecular approaches to HGG with particular attention to specific chaperones, also called heat shock proteins (Hsps), which represent potential novel biomarkers to detect and follow up HGG, and could also be therapeutic agents.

Proteomic Analysis of Liquid Biopsy from Tumor-Draining Vein Indicates that High Expression of Exosomal ECM1 Is Associated with Relapse in Stage I-III Colon Cancer

BACKGROUND: The analysis of exosomes in blood obtained from the tumor-draining mesenteric vein (MV) can identify tumor biomarkers before they reach target organs and form the premetastatic niche where circulating tumor cells can anchor. Our group has recently shown that microRNAs in plasma from the MV—but not the peripheral vein (PV)—have been related to liver metastases in colon cancer (CC) patients. Here we examine the exosomal protein cargo in plasma from the MV and paired PV in 31 CC patients. PATIENTS AND METHODS: The study included patients who were initially diagnosed with stage I-III CC and 10 healthy controls. Exosomes from the MV and PV of all patients and controls were isolated by ultracentrifugation and confirmed by cryogenic transmission electron microscopy. High-throughput proteomic analysis by mass spectrometry was used to identify expression levels of exosomal proteins. Findings were confirmed by Western blot. RESULTS: Exosomal ECM1 protein was more highly expressed in patients than in controls and was 13.55 times higher in MV from relapsed than relapse-free patients. High exosomal ECM1 expression was associated with liver metastases. Patients with high exosomal ECM1 expression in MV—but not PV—plasma had shorter time to relapse than those with low ECM1 expression (P = .04). CONCLUSION: High levels of exosomal ECM1 protein can identify CC patients with a higher risk of relapse. The analysis of exosomes isolated from the tumor-draining MV is a promising method for the identification of biomarkers before they reach the target organ.

The histone deacetylase inhibitor SAHA induces HSP60 nitration and its extracellular release by exosomal vesicles in human lung-derived carcinoma cells

HSP60 undergoes changes in quantity and distribution in some types of tumors suggesting a participation of the chaperonin in the mechanism of transformation and cancer progression. Suberoylanilide hydroxamic acid (SAHA), a member of a family of histone deacetylase inhibitors (HDACi), has anti-cancer potential but its interaction, if any, with HSP60 has not been elucidated. We investigated the effects of SAHA in a human lung-derived carcinoma cell line (H292). We analysed cell viability and cycle; oxidative stress markers; mitochondrial integrity; HSP60 protein and mRNA levels; and HSP60 post-translational modifications, and its secretion. We found that SAHA is cytotoxic for H292 cells, interrupting the cycle at the G2/M phase, which is followed by death; cytotoxicity is associated with oxidative stress, mitochondrial damage, and diminution of intracellular levels of HSP60; HSP60 undergoes a post-translational modification and becomes nitrated; and nitrated HSP60 is exported via exosomes. We propose that SAHA causes ROS overproduction and mitochondrial dysfunction, which leads to HSP60 nitration and release into the intercellular space and circulation to interact with the immune system. These successive steps might constitute the mechanism of the anti-tumor action of SAHA and provide a basis to design supplementary therapeutic strategies targeting HSP60, which would be more efficacious than the compound alone.

Immunohistochemistry of Human Hsp60 in Health and Disease: From Autoimmunity to Cancer

Hsp60 (also called Cpn60) is a chaperonin with essential functions for cell physiology and survival. Additionally, its involvement in the pathogenesis of a variety of diseases (e.g., some autoimmune disorders and cancer) is becoming evident with new research. For example, the distribution and levels of Hsp60 in cells and tissues have been found altered in many pathologic conditions, and the significance of these alterations is being investigated in a number of laboratories. The aim of this ongoing research is to determine the meaning of these Hsp60 alterations with regard to pathogenetic mechanisms, diagnosis, classification of lesions, and assessing prognosis and response to treatment.Hsp60 occurs in the mitochondria, i.e., its typical residence according to classic knowledge, and also in other locales, such as the cytosol, the cell membrane, the intercellular space, and biological fluids (e.g., blood and cerebrospinal fluid). Detection and quantitative determinations in all these locations are becoming essential components of laboratory pathology in clinics and research. Consequently, immunohistochemistry targeting Hsp60 is also becoming essential for pathologists and researchers interested in disorders involving this chaperonin.In this chapter, we summarize some recent discoveries on the participation of Hsp60 in the pathogenesis of human diseases, and describe in detail how to perform immunohistochemical reactions for detecting the chaperonin, determining its location, and measuring its quantitative levels.

Tumor-derived exosomes in colorectal cancer progression and their clinical applications

Colorectal cancer (CRC) ranks as the third leading cause of cancer mortality in both of men and women worldwide due to its metastatic properties and resistance to current treatment. Recent studies have shown that tumor-derived exosomes play emerging roles in the development of cancer. Exosomes are nano-sized extracellular vesicles (EVs) that contain lipids, proteins, DNAs, and RNA species (mRNA, miRNA, long non-coding RNA). These exosomal cargos can be transferred locally and systemically, after taken by recipient cells, so exosomes represent a new form of intercellular communication. There is increasing evidence demonstrating that exosomes control a wide range of pathways bolstering tumor development, metastasis and drug resistance. This review provides an in-depth and timely summary of the role of exosomes in CRC. We first describe the common features and biogenesis of exosomes. We then highlight important findings that support the emerging roles of exosomes in CRC cell growth, invasion and metastasis, as well as resistance to treatment. Finally, we discuss the clinical application of exosomes as diagnostic biomarkers, in vivo drug delivery system and the potential of novel exosome-based immunotherapy for CRC.

Exosomal HSP60: a potentially useful biomarker for diagnosis, assessing prognosis, and monitoring response to treatment

INTRODUCTION

Cell-to-cell communication is imperative for life and it is mediated by sending and receiving information via the secretion and subsequent receptor-mediated detection of biological molecules. Exosomes (EXs) secreted from cells to the extracellular environment play an important role in intercellular communication in normal and pathological conditions. Areas covered: New evidence indicates that tumor cells-derived EXs contribute to cancer progression through the modulation of tumor microenvironment. The exosomal heat shock protein 60 (HSP60) is very likely a key player in intercellular cross-talk, particularly during the progress of diseases, such as cancer. Many studies have focused on the extracellular roles played by HSP60 that pertain to cancer development and immune system stimulation. Our experimental data in vitro and in vivo demonstrated that HSP60 occurs on the surface of EXs secreted by tumour cells. Expert commentary: Exosomal HSP60 has great potential for clinical applications, as a 'liquid biopsy', including its use as biomarker for diagnostics, assessing prognosis, and monitoring disease progression and response to treatment, particularly in cancer.

Unconventional Secretion of Heat Shock Proteins in Cancer

Heat shock proteins (HSPs) are abundant cellular proteins involved with protein homeostasis. They have both constitutive and inducible isoforms, whose expression levels are further increased by stress conditions, such as temperature elevation, reduced oxygen levels, infection, inflammation and exposure to toxic substances. In these situations, HSPs exert a pivotal role in offering protection, preventing cell death and promoting cell recovery. Although the majority of HSPs functions are exerted in the cytoplasm and organelles, several lines of evidence reveal that HSPs are able to induce cell responses in the extracellular milieu. HSPs do not possess secretion signal peptides, and their secretion was subject to widespread skepticism until the demonstration of the role of unconventional secretion forms such as exosomes. Secretion of HSPs may confer immune system modulation and be a cell-to-cell mediated form of increasing stress resistance. Thus, there is a wide potential for secreted HSPs in resistance of cancer therapy and in the development new therapeutic strategies.

Acridine Orange/exosomes increase the delivery and the effectiveness of Acridine Orange in human melanoma cells: A new prototype for theranostics of tumors

Specifically targeted drug delivery systems with low immunogenicity and toxicity are deemed to increase efficacy of cancer chemotherapy. Acridine Orange (AO) is an acidophilic dye with a strong tumoricidal action following excitation with a light source at 466 nm. However, to date the clinical use of AO is limited by the potential side effects elicited by systemic administration. The endogenous nanocarrier exosomes have been recently introduced as a natural delivery system for therapeutic molecules. In this article, we show the outcome of the administration to human melanoma cells of AO charged Exosomes (Exo-AO), in both monolayer and spheroid models. The results showed an extended drug delivery time of Exo-AO to melanoma cells as compared to the free AO, improving the cytotoxicity of AO. This study shows that Exo-AO have a great potential for a real exploitation as a new theranostic approach against tumors based on AO delivered through the exosomes.