Circulating biomarkers in malignant melanoma

Exosomal Non-coding RNAs: A New Approach to Melanoma Diagnosis and Therapeutic Strategy

Malignant melanoma (MM) is a highly aggressive cancer with a poor prognosis. Currently, although a variety of therapies are available for treating melanoma, MM is still a serious threat to the patient's life due to numerous factors, such as the recurrence of tumors, the emergence of drug resistance, and the lack of effective therapeutic agents. Exosomes are biologically active lipid-bilayer extracellular vesicles secreted by diverse cell types that mediate intercellular signal communication. Studies found that exosomes are involved in cancer by carrying multiple bioactive molecules, including non-- coding RNAs (ncRNAs). The ncRNAs have been reported to play an important role in regulating proliferation, angiogenesis, immune regulation, invasion, metastasis, and treatment resistance of tumors. However, the functional role of exosomal ncRNAs in MM remains unknown. Therefore, this review summarizes the current state of melanoma diagnosis, treatment, and the application of exosomal ncRNAs in MM patients, which may provide new insights into the mechanisms involved in melanoma progression and serve as biomarkers for diagnosis and therapeutic targets.

Promising and Minimally Invasive Biomarkers: Targeting Melanoma

The therapeutic landscape of malignant melanoma has been radically reformed in recent years, with novel treatments emerging in both the field of cancer immunotherapy and signalling pathway inhibition. Large-scale tumour genomic characterization has accurately classified malignant melanoma into four different genomic subtypes so far. Despite this, only somatic mutations in BRAF oncogene, as assessed in tumour biopsies, has so far become a validated predictive biomarker of treatment with small molecule inhibitors. The biology of tumour evolution and heterogeneity has uncovered the current limitations associated with decoding genomic drivers based only on a single-site tumour biopsy. There is an urgent need to develop minimally invasive biomarkers that accurately reflect the real-time evolution of melanoma and that allow for streamlined collection, analysis, and interpretation. These will enable us to face challenges with tumour tissue attainment and process and will fulfil the vision of utilizing "liquid biopsy" to guide clinical decisions, in a manner akin to how it is used in the management of haematological malignancies. In this review, we will summarize the most recent published evidence on the role of minimally invasive biomarkers in melanoma, commenting on their future potential to lead to practice-changing discoveries.

Assessment of the oxidative damage and apoptotic pathway related to furan cytotoxicity in cultured mouse Leydig cells

Research on heat-induced food contamination is being given more attention as a result of the health risks that have been publicly revealed in recent years. Furan is known as a colorless, combustible, heterocyclic aromatic organic molecule and is formed when food products are processed and stored. It has been established that furan, which is inevitably ingested, has a deleterious impact on human health and causes toxicity. Furan is known to have adverse effects on the immune system, neurological system, skin, liver, kidney, and fat tissue. Infertility caused by furan is a result of its damaging effects on several tissues and organs as well as the reproductive system. Although studies on the adverse effects of furan on the male reproductive system have been performed, there is no study revealing apoptosis in Leydig cells at the gene level. In this study, TM3 mouse Leydig cells were exposed to 250- and 2,500-μM concentrations of furan for 24 h. The findings demonstrated that furan decreased cell viability and antioxidant enzyme activity while increasing lipid peroxidation, reactive oxygen species, and apoptotic cell rates. Furan also increased the expression of the important apoptotic genes Casp3 and Trp53 while decreasing the expression of another pro-apoptotic gene, Bcl2, and antioxidant genes Sod1, Gpx1, and Cat. In conclusion, these results imply that furan may cause loss of cell function in mouse Leydig cells responsible for testosterone biosynthesis by impairing the efficiency of the antioxidant system, possibly by inducing cytotoxicity, oxidative stress, and apoptosis.

Extracellular vesicles and melanoma: New perspectives on tumor microenvironment and metastasis

Secreted extracellular vesicles (EVs) are lipid bilayer particles without functional nucleus naturally released from cells which constitute an intercellular communication system. There is a broad spectrum of vesicles shed by cells based on their physical properties such as size (small EVs and large EVs), biogenesis, cargo and functions, which provide an increasingly heterogenous landscape. In addition, they are involved in multiple physiological and pathological processes. In cancer, EV release is opted by tumor cells as a beneficial process for tumor progression. Cutaneous melanoma is a cancer that originates from the melanocyte lineage and shows a favorable prognosis at early stages. However, when melanoma cells acquire invasive capacity, it constitutes the most aggressive and deadly skin cancer. In this context, extracellular vesicles have been shown their relevance in facilitating melanoma progression through the modulation of the microenvironment and metastatic spreading. In agreement with the melanosome secretory capacity of melanocytes, melanoma cells display an enhanced EV shedding activity that has contributed to the utility of melanoma models for unravelling EV cargo and functions within a cancer scenario. In this review, we provide an in-depth overview of the characteristics of melanoma-derived EVs and their role in melanoma progression highlighting key advances and remaining open questions in the field.

The Interplay between Tumour Microenvironment Components in Malignant Melanoma

Malignant melanoma has shown an increasing incidence during the last two decades, exhibiting a large spectrum of locations and clinicopathological characteristics. Although current histopathological, biochemical, immunohistochemical, and molecular methods provide a deep insight into its biological behaviour and outcome, melanoma is still an unpredictable disease, with poor outcome. This review of the literature is aimed at updating the knowledge regarding melanoma’s clinicopathological and molecular hallmarks, including its heterogeneity and plasticity, involving cancer stem cells population. A special focus is given on the interplay between different cellular components and their secretion products in melanoma, considering its contribution to tumour progression, invasion, metastasis, recurrences, and resistance to classical therapy. Furthermore, the influences of the specific tumour microenvironment or “inflammasome”, its association with adipose tissue products, including the release of “extracellular vesicles”, and distinct microbiota are currently studied, considering their influences on diagnosis and prognosis. An insight into melanoma’s particular features may reveal new molecular pathways which may be exploited in order to develop innovative therapeutic approaches or tailored therapy.

Low dose gamma irradiation attenuates cyclophosphamide-induced cardiotoxicity in rats: role of NF-κB signaling pathway

PURPOSE

Cyclophosphamide (Cyp) is one of the most commonly used, wide spectrum chemotherapeutic agents. Cyp has multi-organ toxicities that are dose limiting, thus it's mostly used in chemotherapeutic combinations. Radiation is well known as a hazardous sort of energy, recent studies are interested in studying the beneficial therapeutic effects of low-dose gamma radiation. This study examined the protective effect of two different doses/dose-rates of irradiation either alone or combined with telmisartan against Cyp-induced cardiotoxicity.

MATERIALS AND METHODS

Rats were divided into seven groups; (1): Control, (2): Cyp, (3-4): 0.05 Gy low dose rate (LDR) irradiation, 0.25 Gy high dose rate (HDR) irradiation, respectively, prior to Cyp dose, (5-7): telmisartan either alone or with 0.05 Gy LDR-irradiation or 0.25 Gy HDR-irradiation, respectively, prior to Cyp dose. The current investigation studied the effect of Cyp alone or combined with different treatment regimens on serum cTn-I and LDH, nuclear factor-κB (NF-κB) pathway (p65/IκB/IKK-α/IKK-ß) in the myocardium. Pro-inflammatory cytokines IL-1ß, IL-6 and TNF-α were assessed in addition to histopathological examination of the heart.

RESULTS

Low-dose irradiation attenuated cardiac enzymes, pro-inflammatory cytokines, NF-κB content, and histology, in both low and HDRs. Furthermore, the combination of low-dose irradiation with telmisartan (an angiotensin-II receptor type-1 blocker and a known cardio-protective drug) offered the best histological results.

CONCLUSIONS

Low-dose irradiation-induced amelioration is partially but not completely through canonical activation of NF-κB, and may have another atypical pathway. While telmisartan probably ameliorates NF-κB totally through canonical pathway.

RAGE Signaling in Melanoma Tumors

Despite recent progresses in its treatment, malignant cutaneous melanoma remains a cancer with very poor prognosis. Emerging evidences suggest that the receptor for advance glycation end products (RAGE) plays a key role in melanoma progression through its activation in both cancer and stromal cells. In tumors, RAGE activation is fueled by numerous ligands, S100B and HMGB1 being the most notable, but the role of many other ligands is not well understood and should not be underappreciated. Here, we provide a review of the current role of RAGE in melanoma and conclude that targeting RAGE in melanoma could be an approach to improve the outcomes of melanoma patients.

Influence of AS-7 on the storage lesion in young and old circulating erythrocytes

Blood and its components are stored to meet the demands of blood transfusion. Erythrocytes undergo progressive modifications during storage known as storage lesions. Storage solutions were developed to improve shelf life and extend red cell viability. Therefore, the objective of this study is to analyze the effects of AS-7 on young and old erythrocytes during storage. Blood was collected from the blood bank at Kempegowda Institute of Medical Sciences (KIMS) hospital, Bengaluru. Erythrocytes were isolated from whole blood and separated based on its age using Percoll density gradient. The young and old erythrocytes were stored in AS-7 for 35 days and every 5th day, oxidative stress markers - Hemoglobin (Hb), Oxidative Hemolysis, Mechanical Fragility, Sialic Acid, Superoxides, Glucose, Lactate Dehydrogenase (LDH), Glutathione, antioxidant capacity (TAC_CUPRAC), Plasma Membrane Redox System (PMRS), antioxidant enzymes, lipid peroxidation, and protein oxidation products were assessed. Hb, glucose, TAC_CUPRAC, and superoxide dismutase reduced, while oxidative hemolysis, mechanical fragility, protein oxidation, and lipid peroxidation products increased in young and old cells over storage. LDH, PMRS, catalase, advanced oxidation protein products, and conjugate dienes were significant in old cells from day 5 itself, whereas in young cells towards the end of storage (from day 25). Oxidative insult was higher in old cells compared to young cells. AS-7 was beneficial to young erythrocytes during storage and thus laying the foundation for the possibilities of utilizing young cells as models for storage studies.

Clinical Relevance of Liquid Biopsy in Melanoma and Merkel Cell Carcinoma

Melanoma and Merkel cell carcinoma are two aggressive skin malignancies with high disease-related mortality and increasing incidence rates. Currently, invasive tumor tissue biopsy is the gold standard for their diagnosis, and no reliable easily accessible biomarker is available to monitor patients with melanoma or Merkel cell carcinoma during the disease course. In these last years, liquid biopsy has emerged as a candidate approach to overcome this limit and to identify biomarkers for early cancer diagnosis, prognosis, therapeutic response prediction, and patient follow-up. Liquid biopsy is a blood-based non-invasive procedure that allows the sequential analysis of circulating tumor cells, circulating cell-free and tumor DNA, and extracellular vesicles. These innovative biosources show similar features as the primary tumor from where they originated and represent an alternative to invasive solid tumor biopsy. In this review, the biology and technical challenges linked to the detection and analysis of the different circulating candidate biomarkers for melanoma and Merkel cell carcinoma are discussed as well as their clinical relevance.

The power of microRNAs as diagnostic and prognostic biomarkers in liquid biopsies

In the last decades, progresses in medical oncology have ameliorated the treatment of patients and their outcome. However, further improvements are still necessary, in particular for certain types of tumors such as pancreatic, gastric, and lung cancer as well as acute myeloid leukemia where early detection and monitoring of the disease are crucial for final patient outcome. Liquid biopsy represents a great advance in the field because it is less invasive, less time-consuming, and safer compared to classical biopsies and it can be useful to monitor the evolution of the disease as well as the response of patients to therapy. Liquid biopsy allows the detection of circulating tumor cells, nucleic acids, and exosomes not only in blood but also in different biological fluids: urine, saliva, pleural effusions, cerebrospinal fluid, and stool. Among the potential biomarkers detectable in liquid biopsies, microRNAs (miRNAs) are gaining more and more attention, since they are easily detectable, quite stable in biological fluids, and show high sensitivity. Many data demonstrate that miRNAs alone or in combination with other biomarkers could improve the diagnostic and prognostic power for many different tumors. Despite this, standardization of methods, sample preparation, and analysis remain challenging and a huge effort should be made to address these issues before miRNA biomarkers can enter the clinic. This review summarizes the main findings in the field of circulating miRNAs in both solid and hematological tumors.

Biomarker predictors for immunotherapy benefit in breast: beyond PD-L1

PURPOSE OF REVIEW

Immune checkpoint blockade (ICB) has changed the clinical course of multiple cancer types and durable responses have now been observed in breast cancer (BC) patients. Most data suggest that, compared to other subtypes, triple-negative BC (TNBC) patients are more responsive to ICB, and anti-PD-L1 therapy is now approved in PD-L1+ metastatic TNBC, in combination with chemotherapy.

RECENT FINDINGS

Nearly 40% of PD-L1+ TNBC patients did not respond to this combination. Thus, additional biomarkers appear to be necessary to more precisely identify potential responders. A comprehensive analysis of the breast tumor microenvironment (TME) and peripheral blood may identify potential biomarkers for a more accurate selection of patients likely to respond to ICB.

SUMMARY

Herein, we summarize key features of the breast TME, and beyond, that may hold predictive power in determining immunotherapy benefit. Incorporation of these features in controlled clinical trials may help further guide personalized care for BC immunotherapy.

S100-EPISPOT: A New Tool to Detect Viable Circulating Melanoma Cells

Metastatic melanoma is one of the most aggressive and drug-resistant cancers with very poor overall survival. Circulating melanoma cells (CMCs) were first described in 1991. However, there is no general consensus on the clinical utility of CMC detection, largely due to conflicting results linked to the use of heterogeneous patient populations and different detection methods. Here, we developed a new EPithelial ImmunoSPOT (EPISPOT) assay to detect viable CMCs based on their secretion of the S100 protein (S100-EPISPOT). Then, we compared the results obtained with the S100-EPISPOT assay and the CellSearch^® CMC kit using blood samples from a homogeneous population of patients with metastatic melanoma. We found that S100-EPISPOT sensitivity was significantly higher than that of CellSearch^®. Specifically, the percentage of patients with ≥2 CMCs was significantly higher using S100-EPISPOT than CellSearch^® (48% and 21%, respectively; p = 0.0114). Concerning CMC prognostic value, only the CellSearch^® results showed a significant association with overall survival (p = 0.006). However, due to the higher sensitivity of the new S100-EPISPOT assay, it would be interesting to determine whether this functional test could be used in patients with non-metastatic melanoma for the early detection of tumor relapse and for monitoring the treatment response.

Serum S100B Levels in Melanoma

Malignant melanoma is a cancer with increasing incidence worldwide with relevant socioeconomic impact. Despite progress in prevention and early detection, it is one of the most lethal forms of skin cancer. Therefore it is urgent need to identify suitable biomarkers in order to improve early diagnosis, precise staging, and prognosis, as well as for therapy selection and monitoring. In this book chapter, we are focusing on S100B and discuss its clinical relevance in melanoma.

Melanoma-Derived Extracellular Vesicles: Focus on Their Proteome

Malignant melanoma is one of the most aggressive types of cancer, and its incidence is increasing rapidly each year. Despite the extensive research into improved diagnostic and treatment methods, early detection and disease constraint still present significant challenges. As successful isolation protocols have been developed, extracellular vesicles (EVs) have become the subject of extensive investigation in terms of their role in cancer progression and as a possible source of disease biomarkers. Besides functional studies, quantitative and qualitative proteomics have recently emerged as promising tools for the advancement of melanoma biomarkers. Nevertheless, the amount of data concerning the proteome of melanoma-derived EVs is still very limited. In this review we cover the current knowledge on protein content of melanoma-derived EVs, with a focus on their potential role in the development and progression of melanomas.

Improved survival prognostication of node-positive malignant melanoma patients utilizing shotgun proteomics guided by histopathological characterization and genomic data

Metastatic melanoma is one of the most common deadly cancers, and robust biomarkers are still needed, e.g. to predict survival and treatment efficiency. Here, protein expression analysis of one hundred eleven melanoma lymph node metastases using high resolution mass spectrometry is coupled with in-depth histopathology analysis, clinical data and genomics profiles. This broad view of protein expression allowed to identify novel candidate protein markers that improved prediction of survival in melanoma patients. Some of the prognostic proteins have not been reported in the context of melanoma before, and few of them exhibit unexpected relationship to survival, which likely reflects the limitations of current knowledge on melanoma and shows the potential of proteomics in clinical cancer research.

Serum exosomal microRNAs as potent circulating biomarkers for melanoma

Exosomes are small homogenous membrane vesicles that derive from the exocytosis process of cells and can contain DNA, microRNAs (miRNAs), and/or proteins. Characterization of the content profile of exosomes may reflect the state of the cells that release them, and this could be predictive of disease. In this study, to explore the potential biomarkers for melanoma, we isolated serous exosomes from 30 patients with melanoma and 30 healthy individuals using the ultracentrifugation method. Five miRNAs were subsequently detected in each sample by quantitative reverse transcription-PCR: miRNA-532-5p, miRNA-106b, miRNA-200c, miRNA-199a-5p, and miRNA-210. Only the levels of exo-miRNA-532-5p and exo-miRNA-106b differed between the two groups (Z=-4.17 and -4.57, respectively, P<0.0001). When these two miRNAs were evaluated individually and in combination in 95 melanoma patients and 95 healthy individuals serum samples, the area under the receiver operating characteristic curve values were 0.867, 0.820, and 0.936, respectively. Furthermore, in blinded tests of samples from 25 melanoma patients and 25 healthy individuals, this panel of miRNAs identified 23/25 patients with melanoma (92.0% sensitivity) and 22/25 healthy individuals (88.0% sensitivity). Our exo-miRNA panel also distinguished patients with metastasis from those without metastasis, patients with stage I-II disease from those with stage III-IV disease, and patients who had received pembrolizumab treatment from those who were untreated. Overall, these results indicate that serum exosomal miRNAs, especially exo-miRNA-532-5p and exo-miRNA-106b, have the potential to be used for monitoring and/or a diagnosis of melanoma in a clinical setting.

Biomarkers of carcinogenesis and tumour growth in patients with cutaneous melanoma and obstructive sleep apnoea

The goal of this study was to assess the relationship between the severity of obstructive sleep apnoea (OSA) and the levels of carcinogenesis- and tumour growth-related biomarkers in patients with cutaneous melanoma.This multicentre observational study included patients who were newly diagnosed with melanoma. The patients were classified as non-OSA (apnoea-hypopnoea index (AHI) 0-5 events·h^-1), mild OSA (AHI 5-15 events·h^-1) and moderate-severe OSA (AHI >15 events·h^-1). ELISAs were performed to analyse the serum levels of hypoxia- and tumour adhesion-related biomarkers (vascular endothelial growth factor (VEGF), interleukin (IL)-8, intracellular adhesion molecule (ICAM) and vascular cell adhesion molecule (VCAM)-1) and markers of tumour aggressiveness (S100 calcium-binding protein B (S100B) and melanoma inhibitory activity (MIA)). A logistic model adjusted for age, sex and body mass index was fitted to each biomarker, and the AHI served as the dependent variable.360 patients were included (52.2% male, median (interquartile range) age 55.5 (43.8-68.0) years and AHI 8.55 (2.8-19.5) events·h^-1). The levels of VEGF, IL-8, ICAM-1, S100B and MIA were not related to the severity of OSA. The levels of VCAM-1 were higher in patients with OSA than those without OSA (mild OSA: odds ratio (OR) 2.07, p=0.021; moderate-severe OSA: OR 2.35, p=0.013).In patients with cutaneous melanoma, OSA was associated with elevated circulating levels of VCAM-1 that could indicate the contribution of OSA in tumorigenesis via integrin-based adhesion.

Advances in Proteomic Techniques for Cytokine Analysis: Focus on Melanoma Research

Melanoma is a skin cancer with permanently increasing incidence and resistance to therapies in advanced stages. Reports of spontaneous regression and tumour infiltration with T-lymphocytes makes melanoma candidate for immunotherapies. Cytokines are key factors regulating immune response and intercellular communication in tumour microenvironment. Cytokines may be used in therapy of melanoma to modulate immune response. Cytokines also possess diagnostic and prognostic potential and cytokine production may reflect effects of immunotherapies. The purpose of this review is to give an overview of recent advances in proteomic techniques for the detection and quantification of cytokines in melanoma research. Approaches covered span from mass spectrometry to immunoassays for single molecule detection (ELISA, western blot), multiplex assays (chemiluminescent, bead-based (Luminex) and planar antibody arrays), ultrasensitive techniques (Singulex, Simoa, immuno-PCR, proximity ligation/extension assay, immunomagnetic reduction assay), to analyses of single cells producing cytokines (ELISpot, flow cytometry, mass cytometry and emerging techniques for single cell secretomics). Although this review is focused mainly on cancer and particularly melanoma, the discussed techniques are in general applicable to broad research field of biology and medicine, including stem cells, development, aging, immunology and intercellular communication.

Novel serum metabolomics-based approach by gas chromatography/triple quadrupole mass spectrometry for detection of human skin cancers: Candidate biomarkers

Skin cancer incidence rates are continuing to rise; however, if detected at an early stage, they can be cured with minimally invasive treatment. Therefore, the identification of novel and robust biomarkers for the early detection of skin cancer is required to improve the quality of life of the patient after treatment. In the present study, we aimed to identify novel biomarkers of skin cancers. We carried out serum metabolomics using gas chromatography/triple quadrupole mass spectrometry for two types of skin cancer: squamous cell carcinoma and melanoma. The changes in the expression of metabolites compared with healthy volunteers were analyzed by principal component analysis. Among all 118 metabolites, 27 in patients with squamous cell carcinoma and 33 in patients with melanoma showed significant changes in comparison with healthy volunteers. Principal component analysis showed that both skin cancer groups could be distinguished from the healthy volunteers group. We further investigated the specific metabolites most useful for these distinctions. In the squamous cell carcinoma group, these metabolites were glycerol, 4-hydroxybenzoic acid, sebacic acid, fucose and suberic acid. In the melanoma group, these metabolites were glutamic acid, sebacic acid, suberic acid, 4-hydroxybenzoic acid and phenylalanine. The present study identified several metabolites that were distinct for certain skin cancer types, which could potentially be used as diagnostic biomarkers leading to novel clinical management strategies.

Effect of circulating exosomes from transition cows on Madin-Darby bovine kidney cell function

The greatest risk of metabolic and infectious disease in dairy cows is during the transition from pregnancy to lactating (i.e., the transition period). The objective of this experiment was to determine the effects of extracellular vesicles (microvesicles involved in cell-to-cell signaling) isolated from transition cows on target cell function. We previously identified differences in the protein profiles of exosomes isolated from cows divergent in metabolic health status. Therefore, we hypothesized that these exosomes would affect target tissues differently. To investigate this, 2 groups of cows (n = 5/group) were selected based on the concentration of β-hydroxybutyrate and fatty acids in plasma and triacylglycerol concentration in liver at wk 1 and 2 postcalving. Cows with high concentrations of β-hydroxybutyrate, fatty acids, and triacylglycerol were considered at increased risk of clinical disease during the transition period (high-risk group; n = 5) and were compared with cows that had low concentrations of the selected health indicators (low-risk group; n = 5). At 2 time points during the transition period (postcalving at wk 1 and 4), blood was sampled and plasma exosomes were isolated from the high-risk and low-risk cows. The exosomes were applied at concentrations of 10 and 1 µg/mL to 5 × 10³ Madin-Darby bovine kidney cells grown to 50% confluence in 96-well plates. Results indicate a numerical increase in cell proliferation when exosomes from high-risk cows were applied compared with those from low-risk cows. Consistent with an effect on cell proliferation, quantitative reverse transcriptase PCR indicated a trend for upregulation of 3 proinflammatory genes (granulocyte colony-stimulating factor, ciliary neurotrophic factor, and CD27 ligand) with the application of high-risk exosomes, which are involved in cellular growth and survival. Proteomic analysis indicated 2 proteins in the low-risk group that were not identified in the high-risk group (endoplasmin and catalase), which may also be indicative of the metabolic state of origin. It is likely that the metabolic state of the transition cow affects cellular function through exosomal messaging; however, more in-depth research into cross-talk between exosomes and target cells is required to determine whether exosomes influence Madin-Darby bovine kidney cells in this manner.

Lymph node dissection for melanoma: where do we stand?

The extent and timing of regional lymphadenectomy and its role in patients with clinically localized primary melanoma has been the subject of considerable debate. While therapeutic lymphadenectomy for clinically positive nodes is uniformly accepted, the benefit of regional lymphadenectomy in patients with clinically uninvolved lymph nodes potentially harboring micrometastatic disease is less clear. Efforts to better select patients for complete regional lymphadenectomy after sentinel lymph node biopsy are underway. The future holds the promise of more stringent selection criteria and perhaps the identification of subgroups of patients for which a therapeutic benefit may be realized. Moreover, novel sensitive radiological techniques for detecting in vivo micrometastatic nodal disease may improve surgical precision, further decreasing potential morbidities of lymphadenectomy.

Relevance of serum biomarkers associated with melanoma during follow-up of anti-CTLA-4 immunotherapy

Metastatic melanoma is a rapidly spreading cancer whose prognosis remains poor although important therapy advances in recent years. Ipilimumab, an anti-CTLA-4 immunotherapy used in advanced melanoma, is an effective immunotherapy alone or combined with other agents but with few predictive biomarkers of response. Here, we sought to analyze the potential of S100B, MIA, soluble MICA, anti-MICA antibodies and LDH as serum biomarkers of response and survival in a cohort of 77 advanced melanoma patients subjected to ipilimumab. Lower levels of S100B, and LDH at baseline and at weeks 3 and 6 correlated to a better response and survival. After multivariate analysis LDH maintained its independence at baseline and week 6, whereas S100B might be a useful tool for anti-CTLA-4 treatment monitoring after the first two doses of ipilimumab (W6). In addition, higher sMICA serum levels at baseline were associated with less frequency of irAEs.

MicroRNA dysregulation in melanoma

Melanoma is the deadliest form of skin cancer. Current challenges facing the management of melanoma include accurate prediction of individuals who will respond to adjuvant therapies as well as early detection of recurrences. These and other challenges have prompted investigation into biomarkers that could be used as diagnostic, prognostic and therapeutic aids. MicroRNAs (miRs) are small 19-22 nucleotide RNA inhibitors of protein translation. Over 800 different miRs are present within cells and importantly miR expression profiles may vary across different cells types and stages of malignancy. Unique expression profiles have been described for malignant melanoma; however, this work has yet to be translated into routine clinical practice. We highlight pertinent studies involving common miRs implicated in the oncogenesis of melanoma including miR-21, miR-125b, miR-150, miR-155, miR-205, and miR-211. In particular, emphasis is placed upon differential expression across different stages of melanoma progression, prognostic implications and potential mechanistic involvement. Focused efforts on inhibition of these miRs could be the most efficient method of translating preclinical endeavors into clinically meaningful applications.

Pentoxifylline triggers autophagy via ER stress response that interferes with Pentoxifylline induced apoptosis in human melanoma cells

Pentoxifylline (PTX), a non-specific phosphodiesterase inhibitor is known to inhibit the growth of various cancer cells including melanoma. Here in this study, we have found that PTX induces autophagy in human melanoma cell lines (A375 and MeWo). Induction of autophagy is associated with the increase in Atg5 expression as knockdown of Atg5 effectively inhibited PTX mediated autophagy. A decrease in mTOR activation was also observed after PTX treatment. We observed that autophagy was activated as a downstream effector mechanism of ER stress induced by PTX. ER stress response was confirmed by upregulation of IRE-1α, GRP78 and CHOP expression. PTX treatment also resulted in an increase in intracellular calcium (Ca(2+)) level. Ca(2+) is the central player as blocking Ca(2+) by intracellular calcium chelator (BAPTA-AM) effectively inhibited the PTX induced ER stress response as well as autophagy. Moreover, silencing of CHOP also resulted in autophagy inhibition with a decrease in Atg5 expression. Collectively, PTX triggers ER stress response followed by induction of autophagy via involvement of Ca(2+)→CHOP→Atg5 signalling cascade. Interestingly, inhibition of intracellular calcium level by BAPTA-AM significantly increased PTX mediated cell death by augmenting intrinsic apoptotic pathway. Inhibition of autophagy by the ATG5 siRNA and pharmacological inhibitor, chloroquine also enhances PTX induced cell death. Taken together, our results clearly indicate that activation of ER stress response and autophagy provides resistance to PTX mediated apoptosis, and thus, interferes with the anticancer activity of PTX in human melanoma cells.

Circulating melanoma exosomes as diagnostic and prognosis biomarkers

BACKGROUND

Malignant melanoma is an aggressive cancer with an increasing incidence. Exosomes are actively secreted microvesicles, whose characteristics reflect those of the cell they are originated in. The aim of this study was to identify and evaluate the presence of the melanoma biomarkers MIA, S100B and tyrosinase-related protein 2 (TYRP2) in exosomes and their potential clinical utility.

METHODS

Serum samples were obtained from stage IV melanoma patients, melanoma-free patients and healthy controls. Exosomes were precipitated and TYRP2, MIA and S100B concentrations were quantified in serum, exosomes, and exosome-free serum.

RESULTS

Both MIA and S100B were detected in exosomes and correlated significantly with serum concentrations (S100B: r=0.968; MIA: r=0.799; p<0.001). MIA and S100B concentrations in exosomes were significantly higher in melanoma patients than in healthy controls and disease-free patients. However, TYRP2 concentrations in exosomes did not differ between these three groups. ROC curves analysis rendered AUCs for MIA of 0.883 (p<0.01) and of 0.840 for S100B (p<0.01). Patients with exosome MIA concentration higher than 2.5 μg/L showed shorter median survival related to those with lower level (4 versus 11 months; p<0.05).

CONCLUSIONS

MIA and S100B can be detected in exosomes from melanoma patients and their quantification presents diagnostic and prognostic utility.

CD109 is a component of exosome secreted from cultured cells

Exosomes are 50-100-nm-diameter membrane vesicles released from various types of cells. Exosomes retain proteins, mRNAs and miRNAs, which can be transported to surrounding cells. CD109 is a glycosylphosphatidylinositol-anchored glycoprotein, and is released from the cell surface to the culture medium in vitro. Recently, it was reported that secreted CD109 from the cell surface downregulates transforming growth factor-β signaling in human keratinocytes. In this study, we revealed that CD109 is a component of the exosome in conditioned medium. FLAG-tagged human CD109 (FLAG-CD109) in conditioned medium secreted from HEK293 cells expressing FLAG-CD109 (293/FLAG-CD109) was immunoprecipitated with anti-FLAG affinity gel, and the co-precipitated proteins were analyzed by mass spectrometry and western blotting. Exosomal proteins were associated with CD109. We revealed the presence of CD109 in exosome fractions from conditioned medium of 293/FLAG-CD109. Moreover, the localization of CD109 in the exosome was demonstrated using immuno-electron microscopy. When we used HEK293 cells expressing FLAG-tagged truncated CD109, which does not contain the C-terminal region, the association of truncated CD109 with exosomes was not detected in conditioned medium. These findings indicate that CD109 is an exosomal protein and that the C-terminal region of CD109 is required for its presence in the exosome.

Exosomes: Potential in Cancer Diagnosis and Therapy

Exosomes are membrane-bound, intercellular communication shuttles that are defined by their endocytic origin and size range of 30–140 nm. Secreted by nearly all mammalian cell types and present in myriad bodily fluids, exosomes confer messages between cells, proximal and distal, by transporting biofunctional cargo in the form of proteins, nucleic acids, and lipids. They play a vital role in cellular signaling in both normal physiology and disease states, particularly cancer. Exosomes are powerful progenitors in altering target cell phenotypes, particularly in tumorigenesis and cancer progression, with the ability to alter tumor microenvironments and to assist in establishing the pre-metastatic niche. Many aspects of exosomes present them as novel means to identify cancer biomarkers for early detection and therapeutic targets, and using intrinsic and engineered characteristics of exosomes as therapeutic devices to ameliorate the progression of the disease. This review outlines some of the recent and major findings with regard to exosomes in cancer, and their utilization as therapeutic tools.