Increased circulating miR-625-3p: a potential biomarker for patients with malignant pleural mesothelioma

The role of MicroRNAs as early biomarkers of asbestos-related lung cancer: A systematic review and meta-analysis

BACKGROUND

Asbestos is still the leading cause of occupational cancer mortality worldwide. Asbestos-related lung cancer (LC) and malignant pleural mesothelioma (MPM) prognosis is still poor especially at advanced stage, so early diagnosis biomarkers are needed. MicroRNAs (miRNAs) have been proposed as potential early diagnostic biomarkers of asbestos-related LC and MPM.

AIM

To evaluate the role of miRNAs as diagnostic and prognostic biomarkers of asbestos-related LC and MPM by performing a literature systematic review and meta-analysis.

METHODS

MEDLINE, EMBASE via Ovid, PUBMED and Cochrane library databases were systematically searched up to April 2023 to identify relevant articles. A grey literature search was also conducted using the Google Scholar platform. MeSH and free text terms for 'asbestos', 'occupational exposure', 'lung cancer', 'mesothelioma' and 'miRNAs' were used to search the literature. Our systematic review protocol was registered in the PROSPERO database. Study quality was assessed via the Newcastle-Ottawa Scale.

RESULTS

From the search, 331 articles were retrieved, and, after applying our selection criteria, and exclusion of one study for poor quality, 27 studies were included in the review. Most of the studies were hospital-based case-control, conducted in Europe, and evaluated MPM among men only. MiRNAs expression was measured mainly in plasma or serum. MiR-126, miR-132-3p, and miR-103a-3p were the most promising diagnostic biomarkers for MPM, and we estimated a pooled area under the curve (AUC) of 85 %, 73 %, and 50 %, respectively. In relation to MPM prognosis, miR-197‑3p resulted associated with increased survival time. MiR-126, alone and combined with miR-222, was confirmed associated also to LC diagnosis, together with miR-1254 and miR-574-5p; no miRNA was found associated to LC prognosis.

CONCLUSION

Based on our systematic literature review there is suggestive evidence that the expression of specific miRNAs in the blood serum or plasma are associated with asbestos-related LC and MPM diagnosis and prognosis. Further large longitudinal studies are urgently needed to validate these findings and elucidate the underlying mechanisms given the potential important implications for patients' survival.

Deciphering signaling pathway interplay via miRNAs in malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is a highly invasive form of lung cancer that adversely affects the pleural and other linings of the lungs. MPM is a very aggressive tumor that often has an advanced stage at diagnosis and a bad prognosis (between 7 and 12 months). When people who have been exposed to asbestos experience pleural effusion and pain that is not explained, MPM should be suspected. After being diagnosed, most MPM patients have a one- to four-year life expectancy. The life expectancy is approximately six months without treatment. Despite the plethora of current molecular investigations, a definitive universal molecular signature has yet to be discovered as the causative factor for the pathogenesis of MPM. MicroRNAs (miRNAs) are known to play a crucial role in the regulation of gene expression at the posttranscriptional level. The association between the expression of these short, non-coding RNAs and several neoplasms, including MPM, has been observed. Although the incidence of MPM is very low, there has been a significant increase in research focused on miRNAs in the past few years. In addition, miRNAs have been found to have a role in various regulatory signaling pathways associated with MPM, such as the Notch signaling network, Wnt/β-catenin, mutation of KRAS, JAK/STAT signaling circuit, protein kinase B (AKT), and Hedgehog signaling pathway. This study provides a comprehensive overview of the existing understanding of the roles of miRNAs in the underlying mechanisms of pathogenic symptoms in MPM, highlighting their potential as viable targets for therapeutic interventions.

Next Generation Sequencing for miRNA Detection on the Exhaled Breath Condensate: A Pilot Study

Introduction:

Exhaled breath condensate (EBC) sampling has been suggested as a less-invasive and cost-effective method to detect biological macromolecules, including miRNA. To explore the feasibility of its use as a biomarker of early effects of asbestos exposure, we conducted a preliminary test on male volunteers by comparing the miRNA profile in the EBC and the plasma using 2 different sequencing platforms.

Methods:

Six male volunteers, all retired and unexposed to dust or fumes, participated in the test. RNA was extracted from 200 μL EBC samples and same-size plasma samples. Sample aliquots were processed in 2 laboratories using 2 different sequencing platforms: a MiSeq Illumina^® platform and a more performing HiSeq Illumina^® platform.

Results:

The HiSeq3000^® sequencing platform identified twice as many unique molecular indexes (UMI)-validated miRNA as the MiSeq^® platform. The Spearman’s correlation coefficient between EBC counts and plasma counts was significant in 5/6 subjects with either platform (MiSeq^® = 0.128-0.508, P = .026-<.001; HiSeq^® = 0.156-0.412, P = .001-<.001). The intraclass correlation coefficient confirmed the consistency of the miRNA profile over the 6 participants with both biospecimens. Exploring the agreement between the EBC and plasma samples with Bland-Altman plots showed that using the HiSeq3000^® platform substantially improved the EBC miRNA detection rate.

Conclusion:

Our preliminary study confirms that, when using the HiSeq^® sequencing platform, EBC sampling is a suitable, non-invasive method to detect the miRNA profile in healthy subjects.

Serum Extracellular Vesicle-Derived microRNAs as Potential Biomarkers for Pleural Mesothelioma in a European Prospective Study

Malignant pleural mesothelioma (MPM) is an aggressive cancer with a dismal prognosis. Early therapeutic interventions could improve patient outcomes. We aimed to identify a pattern of microRNAs (miRNAs) as potential early non-invasive markers of MPM. In a case-control study nested in the European Prospective Investigation into Cancer and Nutrition cohort, we screened the whole miRNome in serum extracellular vesicles (EVs) of preclinical MPM cases. In a subgroup of 20 preclinical samples collected five years prior MPM diagnosis, we observed an upregulation of miR-11400 (fold change (FC) = 2.6, adjusted p-value = 0.01), miR-148a-3p (FC = 1.5, p-value = 0.001), and miR-409-3p (FC = 1.5, p-value = 0.04) relative to matched controls. The 3-miRNA panel showed a good classification capacity with an area under the receiver operating characteristic curve (AUC) of 0.81 (specificity = 0.75, sensitivity = 0.70). The diagnostic ability of the model was also evaluated in an independent retrospective cohort, yielding a higher predictive power (AUC = 0.86). A signature of EV miRNA can be detected up to five years before MPM; moreover, the identified miRNAs could provide functional insights into the molecular changes related to the late carcinogenic process, preceding MPM development.

Assessment of miR-103a-3p in leukocytes-No diagnostic benefit in combination with the blood-based biomarkers mesothelin and calretinin for malignant pleural mesothelioma diagnosis

Malignant pleural mesothelioma (MPM) is a cancer associated with asbestos exposure and its diagnosis is challenging due to the moderate sensitivities of the available methods. In this regard, miR-103a-3p was considered to increase the sensitivity of established biomarkers to detect MPM. Its behavior and diagnostic value in the Mexican population has not been previously evaluated. In 108 confirmed MPM cases and 218 controls, almost all formerly exposed to asbestos, we quantified miR-103-3a-3p levels in leukocytes using quantitative Real-Time PCR, together with mesothelin and calretinin measured in plasma by ELISA. Sensitivity and specificity of miR-103-3a-3p alone and in combination with mesothelin and calretinin were determined. Bivariate analysis was performed using Mann-Whitney U test and Spearman correlation. Non-conditional logistic regression models were used to calculate the area under curve (AUC), sensitivity, and specificity for the combination of biomarkers. Mesothelin and calretinin levels were higher among cases, remaining as well among males and participants ≤60 years old (only mesothelin). Significant differences for miR-103a-3p were observed between male cases and controls, whereas significant differences between cases and controls for mesothelin and calretinin were observed in men and women. At 95.5% specificity the individual sensitivity of miR-103a-3p was 4.4% in men, whereas the sensitivity of mesothelin and calretinin was 72.2% and 80.9%, respectively. Positive correlations for miR-103a-3p were observed with age, environmental asbestos exposure, years with diabetes mellitus, and glucose levels, while negative correlations were observed with years of occupational asbestos exposure, creatinine, erythrocytes, direct bilirubin, and leukocytes. The addition of miR-103a-3p to mesothelin and calretinin did not increase the diagnostic performance for MPM diagnosis. However, miR-103a-3p levels were correlated with several characteristics in the Mexican population.

Genome wide analysis of circulating miRNAs in growth hormone secreting pituitary neuroendocrine tumor patients’ plasma

Background

Circulating plasma miRNAs have been increasingly studied in the field of pituitary neuroendocrine tumor (PitNET) research. Our aim was to discover circulating plasma miRNAs species associated with growth hormone (GH) secreting PitNETs versus assess how the plasma levels of discovered miRNA candidates are impacted by SSA therapy and whether there is a difference in their levels between GH secreting PitNETs versus other PitNET types and healthy individuals.

Design

We compared plasma miRNA content and levels before and after surgery focusing on GH secreting PitNET patients. Selected miRNA candidates from our data and literature were then tested in a longitudinal manner in somatostatin analogues (SSA) treatment group. Additionally, we validated selected targets in an independent GH secreting PitNET group.

Methods

miRNA candidates were discovered using the whole miRNA sequencing approach and differential expression analysis. Selected miRNAs were then analyzed using real-time polymerase chain reaction (qPCR).

Results

Whole miRNA sequencing discovered a total of 16 differentially expressed miRNAs (DEMs) in GH secreting PitNET patients’ plasma 24 hours after surgery and 19 DEMs between GH secreting PitNET patients’ plasma and non-functioning (NF) PitNET patients’ plasma. Seven miRNAs were selected for further testing of which miR-625-5p, miR-503-5p miR-181a-2-3p and miR-130b-3p showed a significant downregulation in plasma after 1 month of SSA treatment. mir-625-5p was found to be significantly downregulated in plasma of GH secreting PitNET patients vs. NF PitNET patients. miR-625-5p alongside miR-130b-3p were also found to be downregulated in GH PitNETs compared to healthy individuals.

Conclusions

Our study suggests that expression of plasma miRNAs miR-625-5p, miR-503-5p miR-181a-2-3p and miR-130b-3p in GH secreting PitNETs is affected by SSA treatment. Additionally, miR-625-5p can distinguish GH secreting PitNETs from other PitNET types and healthy controls warranting further research on these miRNAs for treatment efficacy.

3-Dimensional mesothelioma spheroids provide closer to natural pathophysiological tumor microenvironment for drug response studies

Traditional studies using cancer cell lines are often performed on a two-dimensional (2D) cell culture model with a low success rate of translating to Phase I or Phase II clinical studies. In comparison, with the advent of developments three-dimensional (3D) cell culture has been championed as the latest cellular model system that better mimics in vivo conditions and pathological conditions such as cancer. In comparison to biospecimens taken from in vivo tissue, the details of gene expression of 3D culture models are largely undefined, especially in mesothelioma – an aggressive cancer with very limited effective treatment options. In this study, we examined the veracity of the 3D mesothelioma cell culture model to study cell-to-cell interaction, gene expression and drug response from 3D cell culture, and compared them to 2D cell and tumor samples. We confirmed via SEM analysis that 3D cells grown using the spheroid methods expressed highly interconnected cell-to-cell junctions. The 3D spheroids were revealed to be an improved mini-tumor model as indicated by the TEM visualization of cell junctions and microvilli, features not seen in the 2D models. Growing 3D cell models using decellularized lung scaffold provided a platform for cell growth and infiltration for all cell types including primary cell lines. The most time-effective method was growing cells in spheroids using low-adhesive U-bottom plates. However, not every cell type grew into a 3D model using the the other methods of hanging drop or poly-HEMA. Cells grown in 3D showed more resistance to chemotherapeutic drugs, exhibiting reduced apoptosis. 3D cells stained with H&E showed cell-to-cell interactions and internal architecture that better represent that of in vivo patient tumors when compared to 2D cells. IHC staining revealed increased protein expression in 3D spheroids compared to 2D culture. Lastly, cells grown in 3D showed very different microRNA expression when compared to that of 2D counterparts. In conclusion, 3D cell models, regardless of which method is used. Showed a more realistic tumor microenvironment for architecture, gene expression and drug response, when compared to 2D cell models, and thus are superior preclinical cancer models.

Serum Expression Levels of Certain miRNAs in Predicting Diagnosis, Prognosis, and Response to Chemotherapy in Malignant Pleural Mesothelioma

Background:

miRNAs are involved in tumor pathogenesis and can therefore be determined in the primary tumor, plasma and serum, and body fluids. As in various cancers, their role in the diagnosis, prognosis, and treatment of patients with malignant pleural mesothelioma (MPM) may be important.

Aims:

To analyze the predictive value of miR-16-5p, miR-29c-3p, miR-31-5p, miR-125a-5p, miR-320a, miR-484 and miR-532-5p expressions for diagnosis, prognosis and response to treatment in patients with MPM.

Study Design:

Prospective case-control study.

Methods:

In the first phase of the study, blood samples were collected from 101 MPM patients before chemotherapy and from 24 healthy donors (HDs). In the second phase, the blood samples were collected from 74 MPM patients who had received chemotherapy when the best overall response and disease recurrence were determined. A quantitative real-time polymerase chain reaction was undertaken to detect the miRNA expression levels. The miRNA expression profiles of MPM patients were compared with those of HDs. The associations between the expression levels of miRNAs and prognosis and response to treatment were then evaluated.

Results:

All miRNAs, except miR-31-5p, were expressed differently in MPM relative to that in HDs. The expression level of miR-16-5p decreased when compared with that of HDs, and the expression levels of miR-29c-3p, miR-125a-5p, miR-320a, miR-484, and miR-532-5p increased when compared with that of HDs. The sensitivity and specificity values of miR-29c-3p, miR-125a-5p, miR-320a, miR-484, and miR-532-5p for discriminating MPM from HDs were 85.9% and 59.1%, 95.1% and 62.5%, 87.1% and 79.2%, 82.2% and 58.3%, and 69.3% and 82.6%, respectively. After adjusting for the histological subtype, stage, and treatment, the miR-29c-3p, miR-125a-5p, and miR-484 were associated with longer survival. The miRNA expression levels did not change longitudinally for the determination of chemotherapy response and recurrence.

Conclusion:

miRNAs may be useful in diagnosing patients with MPM and provides helpful information in determining the prognosis of patients.

MicroRNAs as the critical regulators of cell migration and invasion in thyroid cancer

Thyroid cancer (TC) is one of the most frequent endocrine malignancies that is more common among females. Tumor recurrence is one of the most important clinical manifestations in differentiated TC which is associated with different factors including age, tumor size, and histological features. Various molecular processes such as genetic or epigenetic modifications and non-coding RNAs are also involved in TC progression and metastasis. The epithelial-to-mesenchymal transition (EMT) is an important biological process during tumor invasion and migration that affects the initiation and transformation of early-stage tumors into invasive malignancies. A combination of transcription factors, growth factors, signaling pathways, and epigenetic regulations affect the thyroid cell migration and EMT process. MicroRNAs (miRNAs) are important molecular factors involved in tumor metastasis by regulation of EMT-activating signaling pathways. Various miRNAs are involved in the signaling pathways associated with TC metastasis which can be used as diagnostic and therapeutic biomarkers. Since, the miRNAs are sensitive, specific, and non-invasive, they can be suggested as efficient and optimal biomarkers of tumor invasion and metastasis. In the present review, we have summarized all of the miRNAs which have been significantly involved in thyroid tumor cells migration and invasion. We also categorized all of the reported miRNAs based on their cellular processes to clarify the molecular role of miRNAs during thyroid tumor cell migration and invasion. This review paves the way of introducing a non-invasive diagnostic and prognostic panel of miRNAs in aggressive and metastatic TC patients.

Splicing deregulation, microRNA and Notch aberrations: fighting the three-headed dog to overcome drug resistance in malignant mesothelioma

INTRODUCTION

Malignant mesothelioma (MMe) is an aggressive rare cancer of the mesothelium, associated with asbestos exposure. MMe is currently an incurable disease at all stages mainly due to resistance to treatments. It is therefore necessary to elucidate key mechanisms underlying chemoresistance, in an effort to exploit them as novel therapeutic targets.

AREAS COVERED

Chemoresistance is frequently elicited by microRNA (miRNA) alterations and splicing deregulations. Indeed, several miRNAs, such as miR-29c, have been shown to exert oncogenic or oncosuppressive activity. Alterations in the splicing machinery might also be involved in chemoresistance. Moreover, the Notch signaling pathway, often deregulated in MMe, plays a key role in cancer stem cells formation and self-renewal, leading to drug resistance and relapses.

EXPERT OPINION

The prognosis of MMe in patients varies among different tumors and patient characteristics, and novel biomarkers and therapies are warranted. This work aims at giving an overview of MMe, with a special focus on state-of-the-art treatments and new therapeutic strategies against vulnerabilities emerging from studies on epigenetics factors. Besides, this review is also the first to discuss the interplay between miRNAs and alternative splicing as well as the role of Notch as new promising frontiers to overcome drug resistance in MMe.

Crucial Roles of miR-625 in Human Cancer

Genetic and epigenetic characteristics are core factors of cancer. MicroRNAs (miRNAs) are small non-coding RNAs which regulate gene expression at the post-transcriptional level via binding to corresponding mRNAs. Recently, increasing evidence has proven that miRNAs regulate the occurrence and development of human cancer. Here, we mainly review the abnormal expression of miR-625 in a variety of cancers. In summarizing the role and potential molecular mechanisms of miR-625 in various tumors in detail, we reveal that miR-625 is involved in a variety of biological processes, such as cell proliferation, invasion, migration, apoptosis, cell cycle regulation, and drug resistance. In addition, we discuss the lncRNA-miRNA-mRNA and circRNA-miRNA-mRNA networks and briefly explain the specific mechanisms of competing endogenous RNAs. In conclusion, we reveal the potential value of miR-625 in cancer diagnosis, treatment, and prognosis and hope to provide new ideas for the clinical application of miR-625.

MicroRNA-625-3p improved proliferation and involved chemotherapy resistance via targeting PTEN in high grade ovarian serous carcinoma

Objective

High-grade serous ovarian cancer (HGSOC) is an aggressive gynaecological malignancy and associated with poor prognosis. Here we examined the effects of miR-625-3p on proliferation, treatment, migration and invasion in HGSOC.

Methods

The proliferation of HGSOC cells was evaluated by MTT assay. Transwell assay was performed to examine migration and matrigel assay were used to assess invasion. The effect of miR-625-3p on cisplatin-induced apoptosis was investigated by Caspase-Glo3/7 assay. The dual-luciferase reporter assay was carried out to confirm the potential binding site.

Results

Overexpression of miR-625-3p promoted proliferation, and increased migration and invasion in HGSOC cells. MiR-625-3p significantly inhibited cisplatin sensitivity in HGSOC cells. Meanwhile, miR-625-3p decreased cisplatin-induced apoptosis by regulation of BAX and Bcl-2 expression. Furthermore, aberrant expression of miR-625-3p changed PTEN expression by directly binding to 3’UTR of PTEN. Further study showed miR-625-3p expression was higher in human HGSOC tissue than normal ovarian tissues and associated with higher clinical stage.

Conclusions

miR-625-3p promotes HGSOC growth, involves chemotherapy resistance and might serve as a potential biomarker to predict chemotherapy response and prognosis in HGSOC.

Extracellular Vesicle Enriched miR-625-3p Is Associated with Survival of Malignant Mesothelioma Patients

Malignant mesothelioma (MM) is characterized by poor prognosis and short survival. Extracellular vesicles (EVs) are membrane-bound particles released from cells into various body fluids, and their molecular composition reflects the characteristics of the origin cell. Blood EVs or their miRNA cargo might serve as new minimally invasive biomarkers that would enable earlier detection of MM or treatment outcome prediction. Our aim was to evaluate miRNAs enriched in serum EVs as potential prognostic biomarkers in MM patients in a pilot longitudinal study. EVs were isolated from serum samples obtained before and after treatment using ultracentrifugation on 20% sucrose cushion. Serum EV-enriched miR-103-3p, miR-126-3p and miR-625-3p were quantified using qPCR. After treatment, expression of miR-625-3p and miR-126-3p significantly increased in MM patients with poor treatment outcome (p = 0.012 and p = 0.036, respectively). A relative increase in miR-625-3p expression after treatment for more than 3.2% was associated with shorter progression-free survival (7.5 vs. 19.4 months, HR = 3.92, 95% CI = 1.20-12.80, p = 0.024) and overall survival (12.5 vs. 49.1 months, HR = 5.45, 95% CI = 1.06-28.11, p = 0.043) of MM patients. Bioinformatic analysis showed enrichment of 33 miR-625-3p targets in eight biological pathways. Serum EV-enriched miR-625-3p could therefore serve as a prognostic biomarker in MM and could contribute to a more personalized treatment.

Detection of SARS-CoV-2 Derived Small RNAs and Changes in Circulating Small RNAs Associated with COVID-19

Cleavage of double-stranded RNA is described as an evolutionary conserved host defense mechanism against viral infection. Small RNAs are the product and triggers of post transcriptional gene silencing events. Up until now, the relevance of this mechanism for SARS-CoV-2-directed immune responses remains elusive. Herein, we used high throughput sequencing to profile the plasma of active and convalescent COVID-19 patients for the presence of small circulating RNAs. The existence of SARS-CoV-2 derived small RNAs in plasma samples of mild and severe COVID-19 cases is described. Clusters of high siRNA abundance were discovered, homologous to the nsp2 3′-end and nsp4 virus sequence. Four virus-derived small RNA sequences have the size of human miRNAs, and a target search revealed candidate genes associated with ageusia and long COVID symptoms. These virus-derived small RNAs were detectable also after recovery from the disease. The additional analysis of circulating human miRNAs revealed differentially abundant miRNAs, discriminating mild from severe cases. A total of 29 miRNAs were reduced or absent in severe cases. Several of these are associated with JAK-STAT response and cytokine storm.

Hitting the Bull's-Eye: Mesothelin's Role as a Biomarker and Therapeutic Target for Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is an aggressive cancer with limited treatment options and poor prognosis. MPM originates from the mesothelial lining of the pleura. Mesothelin (MSLN) is a glycoprotein expressed at low levels in normal tissues and at high levels in MPM. Many other solid cancers overexpress MSLN, and this is associated with worse survival rates. However, this association has not been found in MPM, and the exact biological role of MSLN in MPM requires further exploration. Here, we discuss the current research on the diagnostic and prognostic value of MSLN in MPM patients. Furthermore, MSLN has become an attractive immunotherapy target in MPM, where better treatment strategies are urgently needed. Several MSLN-targeted monoclonal antibodies, antibody-drug conjugates, immunotoxins, cancer vaccines, and cellular therapies have been tested in the clinical setting. The biological rationale underpinning MSLN-targeted immunotherapies and their potential to improve MPM patient outcomes are reviewed.

Prediction of differentially expressed microRNAs in blood as potential biomarkers for Alzheimer's disease by meta-analysis and adaptive boosting ensemble learning

BACKGROUND

Blood circulating microRNAs that are specific for Alzheimer's disease (AD) can be identified from differentially expressed microRNAs (DEmiRNAs). However, non-reproducible and inconsistent reports of DEmiRNAs hinder biomarker development. The most reliable DEmiRNAs can be identified by meta-analysis. To enrich the pool of DEmiRNAs for potential AD biomarkers, we used a machine learning method called adaptive boosting for miRNA disease association (ABMDA) to identify eligible candidates that share similar characteristics with the DEmiRNAs identified from meta-analysis. This study aimed to identify blood circulating DEmiRNAs as potential AD biomarkers by augmenting meta-analysis with the ABMDA ensemble learning method.

METHODS

Studies on DEmiRNAs and their dysregulation states were corroborated with one another by meta-analysis based on a random-effects model. DEmiRNAs identified by meta-analysis were collected as positive examples of miRNA-AD pairs for ABMDA ensemble learning. ABMDA identified similar DEmiRNAs according to a set of predefined criteria. The biological significance of all resulting DEmiRNAs was determined by their target genes according to pathway enrichment analyses. The target genes common to both meta-analysis- and ABMDA-identified DEmiRNAs were collected to construct a network to investigate their biological functions.

RESULTS

A systematic database search found 7841 studies for an extensive meta-analysis, covering 54 independent comparisons of 47 differential miRNA expression studies, and identified 18 reliable DEmiRNAs. ABMDA ensemble learning was conducted based on the meta-analysis results and the Human MicroRNA Disease Database, which identified 10 additional AD-related DEmiRNAs. These 28 DEmiRNAs and their dysregulated pathways were related to neuroinflammation. The dysregulated pathway related to neuronal cell cycle re-entry (CCR) was the only statistically significant pathway of the ABMDA-identified DEmiRNAs. In the biological network constructed from 1865 common target genes of the identified DEmiRNAs, the multiple core ubiquitin-proteasome system, that is involved in neuroinflammation and CCR, was highly connected.

CONCLUSION

This study identified 28 DEmiRNAs as potential AD biomarkers in blood, by meta-analysis and ABMDA ensemble learning in tandem. The DEmiRNAs identified by meta-analysis and ABMDA were significantly related to neuroinflammation, and the ABMDA-identified DEmiRNAs were related to neuronal CCR.

Tumor Immune Microenvironment and Genetic Alterations in Mesothelioma

Malignant pleural mesothelioma (MPM) is a rare and fatal disease of the pleural lining. Up to 80% of the MPM cases are linked to asbestos exposure. Even though its use has been banned in the industrialized countries, the cases continue to increase. MPM is a lethal cancer, with very little survival improvements in the last years, mirroring very limited therapeutic advances. Platinum-based chemotherapy in combination with pemetrexed and surgery are the standard of care, but prognosis is still unacceptably poor with median overall survival of approximately 12 months. The genomic landscape of MPM has been widely characterized showing a low mutational burden and the impairment of tumor suppressor genes. Among them, BAP1 and BLM are present as a germline inactivation in a small subset of patients and increases predisposition to tumorigenesis. Other studies have demonstrated a high frequency of mutations in DNA repair genes. Many therapy approaches targeting these alterations have emerged and are under evaluation in the clinic. High-throughput technologies have allowed the detection of more complex molecular events, like chromotripsis and revealed different transcriptional programs for each histological subtype. Transcriptional analysis has also paved the way to the study of tumor-infiltrating cells, thus shedding lights on the crosstalk between tumor cells and the microenvironment. The tumor microenvironment of MPM is indeed crucial for the pathogenesis and outcome of this disease; it is characterized by an inflammatory response to asbestos exposure, involving a variety of chemokines and suppressive immune cells such as M2-like macrophages and regulatory T cells. Another important feature of MPM is the dysregulation of microRNA expression, being frequently linked to cancer development and drug resistance. This review will give a detailed overview of all the above mentioned features of MPM in order to improve the understanding of this disease and the development of new therapeutic strategies.

6 Circulating miRNAs can be used as Non-invasive Biomarkers for the Detection of Cervical Lesions

Background: Cervical cancer is the most common malignant tumor in the female reproductive system, while the efficacy of routine screening strategy is unsatisfied. New molecular tests need to be developed. miRNAs participate in many pathologic processes, and circulating miRNAs are promising non-invasive biomarkers in tumors.

Objectives: This study aimed to identify the circulating miRNAs associated with both cervical cancer and cervical intraepithelial neoplasia (CIN), and establish a non-invasive classifier for cervical lesions using circulating miRNAs.

Methods: This study consisted of 5 steps: miRNAs screening, miRNAs validation, classifier establishment, independent validation and in silico analyses. Three cohorts were included in our study: In screening stage, 24 samples including 14 cases and 10 controls were retrieved; In validation stage, 380 samples including 200 cases and 180 controls were recruited; In independent validation stage, 47 samples comprising 26 cases and 21 controls were included. miRNAs were quantified by RT-qPCR. A classifier was built with random forest algorithm using validation samples and selected miRNAs, which were then validated in an independent cohort. To explore the function of selected miRNAs, in silico analyses were performed. Target genes of selected miRNAs were predicted by the overlap of three online tools. Enrichment analyses were executed with predicted target genes. Differential analysis of target genes was carried out with open access expression assay datasets of cervical tissues.

Results: 6 miRNAs (hsa-miR-26b-5p, hsa-miR-146b-5p, hsa-miR-191-5p, hsa-miR-484, hsa-miR-574-3p, hsa-miR-625-3p) were screened out from 754 miRNAs. They were associated with cervical lesions and were selected to establish a classifier. The accuracy of the classifier were 0.7218 (0.7117, 0.7319) in validation samples, which was 0.7021 in the independent cohort. 958 target genes were predicted and enriched in 23 pathways (MAPK, human papillomavirus infection and Wnt signaling pathway, etc.). 55 genes were identified as the most likely target genes by differential analysis.

Conclusion: The 6 circulating miRNAs were related to cervical lesions and could serve as non-invasive biomarkers.

ERS/ESTS/EACTS/ESTRO guidelines for the management of malignant pleural mesothelioma

The European Respiratory Society (ERS)/European Society of Thoracic Surgeons (ESTS)/European Association for Cardio-Thoracic Surgery (EACTS)/European Society for Radiotherapy and Oncology (ESTRO) task force brought together experts to update previous 2009 ERS/ESTS guidelines on management of malignant pleural mesothelioma (MPM), a rare cancer with globally poor outcome, after a systematic review of the 2009-2018 literature. The evidence was appraised using the Grading of Recommendations, Assessment, Development and Evaluation approach. The evidence syntheses were discussed and recommendations formulated by this multidisciplinary group of experts. Diagnosis: pleural biopsies remain the gold standard to confirm the diagnosis, usually obtained by thoracoscopy but occasionally via image-guided percutaneous needle biopsy in cases of pleural symphysis or poor performance status. Pathology: standard staining procedures are insufficient in ∼10% of cases, justifying the use of specific markers, including BAP-1 and CDKN2A (p16) for the separation of atypical mesothelial proliferation from MPM. Staging: in the absence of a uniform, robust and validated staging system, we advise using the most recent 2016 8th TNM (tumour, node, metastasis) classification, with an algorithm for pretherapeutic assessment. Monitoring: patient's performance status, histological subtype and tumour volume are the main prognostic factors of clinical importance in routine MPM management. Other potential parameters should be recorded at baseline and reported in clinical trials. Treatment: (chemo)therapy has limited efficacy in MPM patients and only selected patients are candidates for radical surgery. New promising targeted therapies, immunotherapies and strategies have been reviewed. Because of limited data on the best combination treatment, we emphasize that patients who are considered candidates for a multimodal approach, including radical surgery, should be treated as part of clinical trials in MPM-dedicated centres.

Molecular Fingerprints of Malignant Pleural Mesothelioma: Not Just a Matter of Genetic Alterations

Malignant pleural mesothelioma (MPM) is a clinical emergency of our time. Being strongly associated with asbestos exposure, incidence of this cancer is ramping up these days in many industrialized countries and it will soon start to increase in many developing areas where the use of this silicate derivate is still largely in use. Deficiency of reliable markers for the early identification of these tumors and the limited efficacy of the currently available therapeutic options are the basis of the impressive mortality rate of MPM. These shortcomings reflect the very poor information available about the molecular basis of this disease. Results of the recently released deep profiling studies point to the epigenome as a central element in MPM development and progression. First, MPM is characterized by a low mutational burden and a highly peculiar set of mutations that hits almost exclusively epigenetic keepers or proteins controlling chromatin organization and function. Furthermore, asbestos does not seem to be associated with a distinctive mutational signature, while the precise mapping of epigenetic changes caused by this carcinogen has been defined, suggesting that alterations in epigenetic features are the driving force in the development of this disease. Last but not least, consistent evidence also indicates that, in the setting of MPM, chromatin rewiring and epigenetic alterations of cancer cells heavily condition the microenvironment, including the immune response. In this review we aim to point to the relevance of the epigenome in MPM and to highlight the dependency of this tumor on chromatin organization and function. We also intend to discuss the opportunity of targeting these mechanisms as potential therapeutic options for MPM.

Reduced SOCS1 Expression in Lung Fibroblasts from Patients with IPF Is Not Mediated by Promoter Methylation or Mir155

The interleukin (IL)-6 family of cytokines and exaggerated signal transducer and activator of transcription (STAT)3 signaling is implicated in idiopathic pulmonary fibrosis (IPF) pathogenesis, but the mechanisms regulating STAT3 expression and function are unknown. Suppressor of cytokine signaling (SOCS)1 and SOCS3 block STAT3, and low SOCS1 levels have been reported in IPF fibroblasts and shown to facilitate collagen production. Fibroblasts and lung tissue from IPF patients and controls were used to examine the mechanisms underlying SOCS1 down-regulation in IPF. A significant reduction in basal SOCS1 mRNA in IPF fibroblasts was confirmed. However, there was no difference in the kinetics of activation, and methylation of SOCS1 in control and IPF lung fibroblasts was low and unaffected by 5′-aza-2′-deoxycytidine’ treatment. SOCS1 is a target of microRNA-155 and although microRNA-155 levels were increased in IPF tissue, they were reduced in IPF fibroblasts. Therefore, SOCS1 is not regulated by SOCS1 gene methylation or microRNA155 in these cells. In conclusion, we confirmed that IPF fibroblasts had lower levels of SOCS1 mRNA compared with control fibroblasts, but we were unable to determine the mechanism. Furthermore, although SOCS1 may be important in the fibrotic process, we were unable to find a significant role for SOCS1 in regulating fibroblast function.

Diagnostic accuracy of circulating miR-126 for malignant pleural mesothelioma: a systematic review and meta-analysis

Background

Circulating microRNAs are novel diagnostic markers for various types of cancer. Several studies have investigated the diagnostic accuracy of circulating miR-126 for malignant pleural mesothelioma (MPM), but the results varied. Therefore, we performed a systematic review and meta-analysis to investigate the diagnostic value of circulating miR-126 for MPM.

Methods

The PubMed database was searched to identify potentially eligible studies published before October 2020. The studies investigating the diagnostic value of circulating miR-126 for MPM were included in a systematic review and meta-analysis. A bivariate model was used to pool eligible studies’ sensitivity and specificity. The revised tool for the quality assessment of diagnostic accuracy studies (QUADAS-2) was used to assess eligible studies’ quality.

Results

Four studies with 156 MPM patients and 459 controls were included in this systematic review and meta-analysis. The pooled diagnostic sensitivity and specificity of circulating miR-126 for MPM were 0.71 and 0.69, respectively. A high risk of bias was observed in the domains of patient selection, index test, and flow and timing.

Conclusions

Circulating miR-126 has limited value for diagnosing MPM. Considering that the available studies have a high risk of bias, further rigorous studies are needed to assess the diagnostic value of circulating miR-126 for MPM.

MicroRNA expression in lung tissues of asbestos-exposed mice: Upregulation of miR-21 and downregulation of tumor suppressor genes Pdcd4 and Reck

OBJECTIVES

Asbestos causes lung cancer and malignant mesothelioma in humans, but the precise mechanism has not been well understood. MicroRNA (miRNA) is a short non-coding RNA that suppresses gene expression and participates in human diseases including cancer. In this study, we examined the expression levels of miRNA and potential target genes in lung tissues of asbestos-exposed mice by microarray analysis.

METHODS

We intratracheally administered asbestos (chrysotile and crocidolite, 0.05 or 0.2 mg/instillation) to 6-week-old ICR male mice four times weekly. We extracted total RNA from lung tissues and performed microarray analysis for miRNA and gene expression. We also carried out real-time polymerase chain reaction (PCR), Western blotting, and immunohistochemistry to confirm the results of microarray analysis.

RESULTS

Microarray analysis revealed that the expression levels of 14 miRNAs were significantly changed by chrysotile and/or crocidolite (>2-fold, P < .05). Especially, miR-21, an oncogenic miRNA, was significantly upregulated by both chrysotile and crocidolite. In database analysis, miR-21 was predicted to target tumor suppressor genes programmed cell death 4 (Pdcd4) and reversion-inducing-cysteine-rich protein with kazal motifs (Reck). Although real-time PCR showed that Pdcd4 was not significantly downregulated by asbestos exposure, Western blotting and immunohistochemistry revealed that PDCD4 expression was reduced especially by chrysotile. Reck was significantly downregulated by chrysotile in real-time PCR and immunohistochemistry.

CONCLUSIONS

This is the first study demonstrating that miR-21 was upregulated and corresponding tumor suppressor genes were downregulated in lung tissues of asbestos-exposed animals. These molecular events are considered to be an early response to asbestos exposure and may contribute to pulmonary toxicity and carcinogenesis.

Circulating biomarkers in malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is an aggressive tumor strictly connected to asbestos exposure. Prognosis is dismal as diagnosis commonly occurs in advanced stage. Radiological screenings have not proven to be effective and also pathological diagnosis may be challenging. In the era of precision oncology, validation of robust non-invasive biomarkers for screening of asbestos-exposed individuals, assessment of prognosis and prediction of response to treatments remains an important unmet clinical need. This review provides an overview on current understanding and possible applications of liquid biopsy in MPM, mostly focused on the utility as diagnostic and prognostic test.

Diagnostic value of microRNAs for malignant pleural mesothelioma: A mini-review

Malignant pleural mesothelioma (MPM) is a type of cancer originating from the pleura with high aggressiveness and poor prognosis. A timely diagnosis is crucial to improve its prognosis. Laboratory biomarkers have significant advantages of reduced invasiveness, low cost, and are observer‐independent, and therefore represent a promising diagnostic tool for MPM. MicroRNA is a family of non‐coding RNA that regulates gene expression at the post‐transcriptional level. Accumulated studies showed that microRNA, either in tissue, circulating, and body fluid, has potential diagnostic value for various disorders. Here, we reviewed the diagnostic value of microRNA for MPM.

Mesothelioma Biomarkers: Discovery in Search of Validation

Malignant pleural mesothelioma (MPM) is an asbestos-related neoplasm that can only be treated successfully when correctly diagnosed and treated early. The asbestos-exposed population is a high-risk group that could benefit from sensitive and specific blood- or tissue-based biomarkers. We review recent work with biomarker development in MPM and literature of the last 20 years on the most promising blood- and tissue-based biomarkers. Proteomic, genomic, and epigenomic platforms are covered. SMRP is the only validated blood-based biomarker with diagnostic, monitoring and prognostic value. To strengthen development and testing of MPM biomarkers, cohorts for validation must be established by enlisting worldwide collaborations.

Mesothelioma Biomarkers: A Review Highlighting Contributions from the Early Detection Research Network

Malignant pleural mesothelioma (MPM) is an asbestos-related neoplasm, which can be treated successfully only if correctly diagnosed and treated in early stages. The asbestos-exposed population serves as a high-risk group that could benefit from sensitive and specific blood- or tissue-based biomarkers. This review details the recent work with biomarker development in MPM and the contributions of the NCI Early Detection Research Network Biomarker Developmental Laboratory of NYU Langone Medical Center. The literature of the last 20 years was reviewed to comment on the most promising of the blood- and tissue-based biomarkers. Proteomic, genomic, and epigenomic platforms as well as novel studies such as "breath testing" are covered. Soluble mesothelin-related proteins (SMRP) have been characterized extensively and constitute an FDA-approved biomarker in plasma with diagnostic, monitoring, and prognostic value in MPM. Osteopontin is found to be a valuable prognostic biomarker for MPM, while its utility in diagnosis is slightly lower. Other biomarkers, such as calretinin, fibulin 3, and High-Mobility Group Box 1 (HMGB1), remain under study and need international validation trials with large cohorts of cases and controls to demonstrate any utility. The EDRN has played a key role in the development and testing of MPM biomarkers by enlisting collaborations all over the world. A comprehensive understanding of previously investigated biomarkers and their utility in screening and early diagnosis of MPM will provide guidance for further future research.See all articles in this CEBP Focus section, "NCI Early Detection Research Network: Making Cancer Detection Possible."

ERS/ESTS/EACTS/ESTRO guidelines for the management of malignant pleural mesothelioma

The European Respiratory Society (ERS)/European Society of Thoracic Surgeons (ESTS)/European Association for Cardio-Thoracic Surgery (EACTS)/European Society for Radiotherapy and Oncology (ESTRO) task force brought together experts to update previous 2009 ERS/ESTS guidelines on management of malignant pleural mesothelioma (MPM), a rare cancer with globally poor outcome, after a systematic review of the 2009-2018 literature. The evidence was appraised using the Grading of Recommendations, Assessment, Development and Evaluation approach. The evidence syntheses were discussed and recommendations formulated by this multidisciplinary group of experts. Diagnosis: pleural biopsies remain the gold standard to confirm the diagnosis, usually obtained by thoracoscopy but occasionally via image-guided percutaneous needle biopsy in cases of pleural symphysis or poor performance status. Pathology: standard staining procedures are insufficient in ∼10% of cases, justifying the use of specific markers, including BAP-1 and CDKN2A (p16) for the separation of atypical mesothelial proliferation from MPM. Staging: in the absence of a uniform, robust and validated staging system, we advise using the most recent 2016 8th TNM (tumour, node, metastasis) classification, with an algorithm for pre-therapeutic assessment. Monitoring: patient's performance status, histological subtype and tumour volume are the main prognostic factors of clinical importance in routine MPM management. Other potential parameters should be recorded at baseline and reported in clinical trials. Treatment: (chemo)therapy has limited efficacy in MPM patients and only selected patients are candidates for radical surgery. New promising targeted therapies, immunotherapies and strategies have been reviewed. Because of limited data on the best combination treatment, we emphasise that patients who are considered candidates for a multimodal approach, including radical surgery, should be treated as part of clinical trials in MPM-dedicated centres.

Malignant Pleural Mesothelioma: Genetic and Microenviromental Heterogeneity as an Unexpected Reading Frame and Therapeutic Challenge

Mesothelioma is a malignancy of serosal membranes including the peritoneum, pleura, pericardium and the tunica vaginalis of the testes. Malignant mesothelioma (MM) is a rare disease with a global incidence in countries like Italy of about 1.15 per 100,000 inhabitants. Malignant Pleural Mesothelioma (MPM) is the most common form of mesothelioma, accounting for approximately 80% of disease. Although rare in the global population, mesothelioma is linked to industrial pollutants and mineral fiber exposure, with approximately 80% of cases linked to asbestos. Due to the persistent asbestos exposure in many countries, a worldwide progressive increase in MPM incidence is expected for the current and coming years. The tumor grows in a loco-regional pattern, spreading from the parietal to the visceral pleura and invading the surrounding structures that induce the clinical picture of pleural effusion, pain and dyspnea. Distant spreading and metastasis are rarely observed, and most patients die from the burden of the primary tumor. Currently, there are no effective treatments for MPM, and the prognosis is invariably poor. Some studies average the prognosis to be roughly one-year after diagnosis. The uniquely poor mutational landscape which characterizes MPM appears to derive from a selective pressure operated by the environment; thus, inflammation and immune response emerge as key players in driving MPM progression and represent promising therapeutic targets. Here we recapitulate current knowledge on MPM with focus on the emerging network between genetic asset and inflammatory microenvironment which characterize the disease as amenable target for novel therapeutic approaches.

MicroRNAs diagnostic and prognostic value as predictive markers for malignant mesothelioma

Malignant mesothelioma is an aggressive tumor resistant to current therapies with a latency period ranging between 20 and 60 years, caused by inhalation of asbestos fibers, that continues to represent a social and healthcare issue. The high percentage of people exposed to asbestos for professional or environmental reasons is associated with the high biopersistence of its fibers and with its widespread use in the last century. Approximately 20-40% of men report an occupational history that might have caused the workplace exposure (criteria Helsinki, 1997). Some authors are evaluating the possible use of bioindicators as a screening and early diagnosis tool. In this regard, the use of microRNAs has been proposed as powerful diagnostic and prognostic biomarkers for many tumors and human diseases. This review focuses on the current state of knowledge on the key role of microRNAs expression as new malignant mesothelioma biomarkers, in early clinical diagnostic applications.

Circulating Epigenetic Biomarkers in Malignant Pleural Mesothelioma: State of the Art and critical Evaluation

Malignant pleural mesothelioma (MPM) is a rare and aggressive cancer, which originates from the mesothelial cells of the pleura and is associated with asbestos exposure. In light of its aggressive nature, late diagnosis and dismal prognosis, there is an urgent need for identification of biomarkers in easily accessible samples (such as blood) for early diagnosis of MPM. In the last 10 years, epigenetic markers, such as DNA methylation and microRNAs (miRNAs), have gained popularity as possible early diagnostic and prognostic biomarkers in cancer research. The aim of this review is to provide a critical analysis of the current evidences on circulating epigenetic biomarkers for MPM and on their translational potential to the clinical practice for early diagnosis and for prognosis.

Evaluation of soluble mesothelin-related peptides and MSLN genetic variability in asbestos-related diseases

Background

Asbestos exposure is associated with increased risk of several diseases, including malignant mesothelioma (MM). Cell surface glycoprotein mesothelin is overexpressed in MM and serum soluble mesothelin-related peptides (SMRP) were already proposed as a diagnostic or prognostic biomarker in MM. However, interindividual variability in serum SMRP levels limits the clinical usefulness. Our primary objective was to investigate the influence of MSLN rs1057147 on serum SMRP levels in asbestos-exposed subjects and patients with asbestos-related diseases as well as on survival in MM.

Subjects and methods

Among 782 asbestos-exposed subjects and patients with asbestos-related diseases, 154 had MM. Serum SMRP levels were determined using sandwich enzyme-linked immunosorbent assay. All subjects were genotyped for MSLN rs1057147 polymorphism using competitive allele-specific polymerase chain reaction. Nonparametric tests, logistic and Cox regression were used in statistical analysis to compare different subject groups.

Results

MM patients had significantly higher SMRP levels than all other subjects (p < 0.001). Compared to wild-type MSLN rs1057147 genotype, both heterozygotes and carriers of two polymorphic alleles had significantly higher SMRP levels among subjects without MM (p < 0.001), but not in MM patients (p = 0.424). If genotype information was included, specificity of SMRP increased from 88.5% to 92.7% for the optimal cutoff value. Overall survival was significantly shorter in MM patients carrying at least one polymorphic rs1057147 allele (HR = 1.72, 95% CI = 1.15-2.55, p = 0.008).

Conclusions

MSLN genetic variability affects serum SMRP levels and was associated with shorter survival of MM patients. Combination of genetic and serum factors could therefore serve as a better diagnostic or prognostic biomarker in MM patients.

Comprehensive Analysis of Aberrantly Expressed Profiles of lncRNAs and miRNAs with Associated ceRNA Network in Lung Adenocarcinoma and Lung Squamous Cell Carcinoma

Lung cancer (LC) continues to be the leading cause of cancer-related deaths worldwide and the prognosis remains poor worldwide. At present, the long non-coding RNAs (lncRNAs) was considered as a part of competing endogenous RNA (ceRNA) network act as natural microRNA (miRNA) sponges to regulate protein-coding gene expression. However, functional roles of lncRNA-mediated ceRNAs in LC are insufficiently understood. To classify the specific mechanism of lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC), we comprehensively compared the expression profiles of mRNAs, lncRNAs and miRNAs obtained from 509 LUAD, 473 LUSC tissues and 49 adjacent non-cancerous lung tissues, based on The Cancer Genome Atlas (TCGA). After screening for differently expressed (DE) mRNAs, DEmiRNAs, DElncRNAs and weighted gene co-expression network analysis (WGCNA) (|log2FC| > 2.0 and an adjusted p value <0.05), a total of 4478 DEmRNAs, 526 DElncRNAs and 75 DEmiRNAs in LUAD, while 6237 DEmRNAs, 843 DElncRNAs and 117 DEmiRNAs in LUSC were discovered. Interaction (PPI) network analysis was performed to identify 656 nodes and 2987 edges (minimum required interaction score > 0.9), as well as 8 different protein-protein interactions. Gene ontology (GO) analysis mainly associated with cell proliferation. KEGG pathway enrichment analyses most partly associated with metabolism pathway and cytokine-cytokine receptor interaction. Finally, the dysregulated lncRNA-miRNA-ceRNA network was constructed based on correlation analyses and a total of 62 dysregulated lncRNAs, 28 DEmRNAs and 18 DEmiRNAs were involved. The most significant lncRNAs included DElncRNAs, LINC00641 and AC004947.2, miRNAs included miR-6860, miR-1285-3p, miR-767-3p and miR-7974, mRNAs included MAP3K3, FGD3 and ATP1B2. Then we analyzed and described the potential characteristics of biological function and pathological roles of the LUAD and LUSC ceRNA co-regulatory network. Our findings revealed ceRNA network will be beneficial for promoting the understanding of lncRNA-mediated ceRNA regulatory mechanisms in the pathogenesis of LUAD and LUSC.

Epigenetic Regulation of miRNA Expression in Malignant Mesothelioma: miRNAs as Biomarkers of Early Diagnosis and Therapy

Asbestos exposure leads to epigenetic and epigenomic modifications that, in association with ROS-induced DNA damage, contribute to cancer onset. Few miRNAs epigenetically regulated in MM have been described in literature; miR-126, however, is one of them, and its expression is regulated by epigenetic mechanisms. Asbestos exposure induces early changes in the miRNAs, which are reversibly expressed as protective species, and their inability to reverse reflects the inability of the cells to restore the physiological miRNA levels despite the cessation of carcinogen exposure. Changes in miRNA expression, which results from genetic/epigenetic changes during tumor formation and evolution, can be detected in fluids and used as cancer biomarkers. This article has reviewed the epigenetic mechanisms involved in miRNA expression in MM, focusing on their role as biomarkers of early diagnosis and therapeutic effects.

Liquid Biopsy in Malignant Pleural Mesothelioma: State of the Art, Pitfalls, and Perspectives

Malignant pleural mesothelioma (MPM) is an aggressive tumor linked to asbestos exposure. Although the risk factors for MPM are well-known, the majority of MPM patients are diagnosed at an advanced stage and have a very poor prognosis. Circulating biomarkers for early diagnosis remain to be identified, and the current standard for MPM diagnosis relies on pleural biopsies. Robust non-invasive tests for the screening of asbestos-exposed subjects are therefore an important unmet clinical need. This review provides a critical summary of recent liquid biopsy-based studies aimed at discovering novel blood-based circulating biomarkers for the early diagnosis and prognostic stratification of MPM patients.

ERS/EACTS statement on the management of malignant pleural effusions

Malignant pleural effusions (MPE) are a common pathology, treated by respiratory physicians and thoracic surgeons alike. In recent years, several well-designed randomized clinical trials have been published that have changed the landscape of MPE management. The European Respiratory Society (ERS) and the European Association for Cardio-Thoracic Surgery (EACTS) established a multidisciplinary collaboration of clinicians with expertise in the management of MPE with the aim of producing a comprehensive review of the scientific literature. Six areas of interest were identified, including the optimum management of symptomatic MPE, management of trapped lung in MPE, management of loculated MPE, prognostic factors in MPE, whether there is a role for oncological therapies prior to intervention for MPE and whether a histological diagnosis is always required in MPE. The literature revealed that talc pleurodesis and indwelling pleural catheters effectively manage the symptoms of MPE. There was limited evidence regarding the management of trapped lung or loculated MPE. The LENT score was identified as a validated tool for predicting survival in MPE, with Brims' prognostic score demonstrating utility in mesothelioma prognostication. There was no evidence to support the use of oncological therapies as an alternative to MPE drainage, and the literature supported the use of tissue biopsy as the gold standard for diagnosis and treatment planning.Management options for malignant pleural effusions have advanced over the past decade, with high-quality randomized trial evidence informing practice in many areas. However, uncertainties remain and further research is required http://ow.ly/rNt730jOxOS.

miR-625-3p and lncRNA GAS5 in Liquid Biopsies for Predicting the Outcome of Malignant Pleural Mesothelioma Patients Treated with Neo-Adjuvant Chemotherapy and Surgery

Combining neo-adjuvant chemotherapy and surgery is part of multimodality treatment of malignant pleural mesothelioma (MPM), but not all patients benefit from this approach. In this exploratory analysis, we investigated the prognostic value of circulating miR-625-3p and lncRNA GAS5 after neo-adjuvant chemotherapy. 36 MPM patients from the SAKK 17/04 trial (NCT00334594), whose blood was available before and after chemotherapy were investigated. RNA was isolated from plasma and reverse transcribed into cDNA. miR-16-5p and β-actin were used as a reference gene for miR-625-3p and GAS5, respectively. After exclusion of samples due to hemolysis or RNA degradation, paired plasma samples from 32 patients before and after chemotherapy were further analyzed. Quantification of miR-625-3p levels in all 64 samples revealed a bimodal distribution and cloning and sequencing of miR-625-3p qPCR product revealed the presence of miR-625-3p isomiRs. Relative change of the circulating miR-625-3p and GAS5 levels after chemotherapy showed that increased circulating miR-625-3p and decreased GAS5 was significantly associated with disease progression (Fisher's test, p = 0.0393). In addition, decreased levels of circulating GAS5 were significantly associated with shorter overall and progression-free survival. Our exploratory analysis revealed a potential value of circulating non-coding RNA for selection of patients likely to benefit from surgery after platinum-based adjuvant chemotherapy.

Genome-wide profiling reveals novel microRNAs in hand-spinning-specific chrysotile exposure

Aim: We aimed to explore miRNA expression profiles in hand-spinning chrysotile exposed workers and their potential influencing factors. Methods: miRNA array technique was applied to screen differentially expressed miRNAs between plasma samples from three exposed workers and three controls. Then, seven selected miRNAs were validated in 143 workers and 100 controls, and the potential influencing factors were revealed by multiple linear regression. Finally, the expression levels of those seven miRNAs were evaluated in human mesothelial cells (Met-5A) that were exposed to chrysotile at 5 μg·cm-2 for 8, 24 and 48 h, respectively. Results & conclusion: Hand-spinning chrysotile exposure can result in differential expression of miRNAs. Several of those miRNAs have positive correlations with asbestos exposure.

Are circulating microRNAs suitable for the early detection of malignant mesothelioma? Results from a nested case-control study

OBJECTIVE

Malignant mesothelioma is an aggressive cancer of the serous membranes. For the detection of the tumor at early stages non- or minimally-invasive biomarkers are needed. The circulating biomarkers miR-132-3p, miR-126-3p, and miR-103a-3p were analyzed in a nested case-control study using plasma samples from 17 prediagnostic mesothelioma cases and 34 matched asbestos-exposed controls without a malignant disease.

RESULTS

Using prediagnostic plasma samples collected in median 8.9 months prior the clinical diagnosis miR-132-3p, miR-126-3p, and miR-103a-3p revealed 0% sensitivity on a defined specificity of 98%. Thus, the analyzed miRNAs failed to detect the cancer in prediagnostic samples, showing that they are not feasible for the early detection of malignant mesothelioma. However, the miRNAs might still serve as possible markers for prognosis and response to therapy, but this needs to be analyzed in appropriate studies.

miR‑625‑5p suppresses inflammatory responses by targeting AKT2 in human bronchial epithelial cells

Asthma is a common chronic inflammatory airway disease; however, whether microRNAs (miRs) could be used in the treatment of asthma remains unclear. The aim of the present study was to investigate the role of miR‑625‑5p in the inflammatory response of human bronchial epithelial cells (HBECs). Inflammation in the HBEC line, 16HBEC, was induced using different concentrations of lipopolysaccharide (LPS), which demonstrated that 1 µg/ml LPS was an appropriate concentration for further experiments. The association between protein kinase B2 (AKT2) and miR‑625‑5p was verified using a luciferase reporter assay. LPS was added to 16HBECs following the administration of miR‑625‑5p mimics or miR‑625‑5p inhibitors, and cells with silenced or overexpressed AKT2 levels. miR‑625‑5p was expressed at a high level in LPS‑activated 16HBECs. Overexpression of miR‑625‑5p inhibited interleukin (IL)‑6 and tumor necrosis factor (TNF)‑α secretion in 16HBECs. Inhibition of miR‑625‑5p enhanced LPS‑induced IL‑6 and TNF‑α secretion. miR‑625‑5p negatively regulated the expression of AKT2 in 16HBECs. A dual‑luciferase reporter assay system confirmed that miR‑625‑5p directly targeted the 3'untranslated region of AKT2. Transfection with a small interfering RNA against AKT2 inhibited inhibitor of κB phosphorylation. In brief, miR‑625‑5p may protect LPS‑induced HBECs by targeting AKT2 and inhibiting the nuclear factor‑κB signaling pathway. Therefore, miR‑625‑5p may function as an inhibitor of asthma airway inflammation in HBECs by targeting AKT2.

miR-625-3p promotes migration and invasion and reduces apoptosis of clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is a common malignancy, yet, the mechanisms underlying tumorigenesis remain unclear. Several miRNAs have been implicated in the development of RCC previously via regulation of target gene expression. As miR-625-3p has recently been identified to play a role in development of other malignancies and is reportedly upregulated in ccRCC, we sought to investigate the role of this miRNA in the progression of ccRCC. Analysis of 30 paired fresh ccRCC tissues and adjacent normal renal tissues revealed that the expression of miR-625-3p was increased in ccRCC tissues compared to normal tissues. Subsequently, in 136 formalin-fixed paraffin-embedded ccRCC tissues, the increased miR-625-3p expression was correlated with poor prognosis for ccRCC patients. The diagnostic value of miR-625-3p was identified in 50 ccRCC patients and 74 healthy controls by ROC curve. miR-625-3p was decreased in serum of ccRCC patients compared to healthy individuals. miR-625-3p could serve as a promising serum biomarker for yielding an area under the receiver operating characteristic curve of 0.792 with 70.3% sensitivity and 80.0% specificity in discriminating ccRCC from healthy individuals. Using in vitro functional assays, we found that overexpression of miR-625-3p promoted migration and invasion of ccRCC cells but reduced ccRCC cell apoptosis. Inhibition of miR-625-3p, on the other hand, exerted the opposite effects. Bioinformatic analyses indicated that predicted gene targets of miR-625-3p are correlated with lower overall survival of ccRCC patients. Together, these findings demonstrate that miR-625-3p promotes ccRCC migration and invasion and reduces apoptosis, providing a prognostic marker for survival and a potential diagnostic and therapeutic target against ccRCC.

MicroRNAs for the Diagnosis and Management of Malignant Pleural Mesothelioma: A Literature Review

Malignant pleural mesothelioma (MPM) is a rare and aggressive tumor with a variable incidence among different countries. Occupational asbestos exposure is the most important etiological factor and a very long latency period is widely reported. In the early phase of the disease, clinical signs are absent or not specific. For this reason, the diagnosis is frequently achieved only in the advanced stages. The histopathological diagnosis per se is also very complex, and no known factor can predict the prognosis with certainty. Nonetheless, current survival rates remain very low, despite the use of standard treatments, which include surgery, chemotherapy and radiotherapy. The identification of new prognostic and/or diagnostic biomarkers, and the discovery of therapeutic targets is a priority and could lead to a real significant impact on the management of malignant pleural mesothelioma. In this scenario, the role of microRNAs is becoming increasingly relevant, with the promise of a quick translation in the current clinical practice. Despite the relative novelty of this field, the number of works and candidate microRNAs that are present in literature is striking. Unfortunately, to date the microRNAs with the most clinical relevance for MPM are still matter of debate, probably due to the variety of approaches, techniques, and collected samples. Although specific microRNAs (e.g., let-7, miR-15 and miR-16, miR-21, miR-34a, and the miR-200 family) have been reported several times from different groups, the heterogeneity of published data reinforces the need of more comprehensive and unified studies on this topic. In this review we collect and discuss the studies focused on the involvement of microRNAs in different aspects of MPM, from their biological role in tumorigenesis and progression, to their possible application as diagnostic, prognostic and predictive biomarkers. Lastly, we examine their potential value as for the design of therapeutic approaches that could benefit MPM patients.

Interplay of non-coding RNAs and approved antimetabolites such as gemcitabine and pemetrexed in mesothelioma

Gemcitabine and pemetrexed are clinically approved antimetabolites for the therapy of mesothelioma diseases. These drugs are often applied in combination with platinum complexes and other drugs. The activity of antimetabolites depended on the expression levels of certain non-coding RNAs, in particular, of small microRNAs (miRNAs) and long non-coding RNAs (lncRNAs). The development of tumor resistance towards antimetabolites was regulated by non-coding RNAs. An overview of the interplay between gemcitabine/pemetrexed antimetabolites and non-coding RNAs in mesothelioma is provided. Further to this, various non-coding RNA-modulating agents are discussed which displayed positive effects on gemcitabine or pemetrexed treatment of mesothelioma diseases. A detailed knowledge of the connections of non-coding RNAs with antimetabolites will be constructive for the design of improved therapies in future.

Clinical significance of serum DRAM1 mRNA, ARSA mRNA, hsa-miR-2053 and lncRNA-RP1-86D1.3 axis expression in malignant pleural mesothelioma

AIM AND BACKGROUND

Malignant pleural mesothelioma (MPM) is a lethal cancer mainly caused by chronic exposure of asbestos. In this pilot study, we aimed to assess the expression of serum RNA-based biomarker panel exploring their clinical utility as diagnostic and prognostic biomarkers for MPM.

METHODS

We have selected an MPM-specific RNA-based biomarker panel through bioinformatics analysis based on the integration of DNA damage regulated autophagy modulator 1 (DRAM1) and arylsulfatase A ( ARSA) gene expression with their epigenetic regulators microRNA ( miR-2053) and long noncoding RNA ( lncRNA-RP1-86D1.3). Then, quantitative real-time polymerase chain reaction (qPCR) validation in sera of 60 MPM patients, 20 chronic asbestos exposure patients, and 20 healthy volunteers was done. Lastly, the prognostic power of the selected panel was assessed.

RESULTS

The expression of serum DRAM1 messenger RNA (mRNA), ARSA mRNA, hsa-miR-2053 and lncRNA-RP1-86D1.3 were positive in 78.3%, 90%, 85%, and 83.3% of MPM patients, respectively. The RNA-based biomarker panel was able to discriminate between MPM patients and controls with high accuracy and their combined sensitivity reached 100% for the diagnosis of MPM. Kaplan-Meier analysis showed that hsa-miR-2053 is an independent prognostic factor of MPM.

CONCLUSION

Our preliminary data revealed that the chosen RNAs play an important role in driving MPM development and progression.

Current and Future Management of Malignant Mesothelioma: A Consensus Report from the National Cancer Institute Thoracic Malignancy Steering Committee, International Association for the Study of Lung Cancer, and Mesothelioma Applied Research Foundation

On March 28- 29, 2017, the National Cancer Institute (NCI) Thoracic Malignacy Steering Committee, International Association for the Study of Lung Cancer, and Mesothelioma Applied Research Foundation convened the NCI-International Association for the Study of Lung Cancer- Mesothelioma Applied Research Foundation Mesothelioma Clinical Trials Planning Meeting in Bethesda, Maryland. The goal of the meeting was to bring together lead academicians, clinicians, scientists, and the U.S. Food and Drug Administration to focus on the development of clinical trials for patients in whom malignant pleural mesothelioma has been diagnosed. In light of the discovery of new cancer targets affecting the clinical development of novel agents and immunotherapies in malignant mesothelioma, the objective of this meeting was to assemble a consensus on at least two or three practice-changing multimodality clinical trials to be conducted through NCI's National Clinical Trials Network.

Genomics and Epigenetics of Malignant Mesothelioma

Malignant mesothelioma is an aggressive and lethal asbestos-related disease. Diagnosis of malignant mesothelioma is particularly challenging and is further complicated by the lack of disease subtype-specific markers. As a result, it is especially difficult to distinguish malignant mesothelioma from benign reactive mesothelial proliferations or reactive fibrosis. Additionally, mesothelioma diagnoses can be confounded by other anatomically related tumors that can invade the pleural or peritoneal cavities, collectively resulting in delayed diagnoses and greatly affecting patient management. High-throughput analyses have uncovered key genomic and epigenomic alterations driving malignant mesothelioma. These molecular features have the potential to better our understanding of malignant mesothelioma biology as well as to improve disease diagnosis and patient prognosis. Genomic approaches have been instrumental in identifying molecular events frequently occurring in mesothelioma. As such, we review the discoveries made using high-throughput technologies, including novel insights obtained from the analysis of the non-coding transcriptome, and the clinical potential of these genetic and epigenetic findings in mesothelioma. Furthermore, we aim to highlight the potential of these technologies in the future clinical applications of the novel molecular features in malignant mesothelioma.

ERS/EACTS statement on the management of malignant pleural effusions

Malignant pleural effusions (MPE) are a common pathology, treated by respiratory physicians and thoracic surgeons alike. In recent years, several well-designed randomised clinical trials have been published that have changed the landscape of MPE management. The European Respiratory Society (ERS) and the European Association for Cardio-Thoracic Surgery (EACTS) established a multidisciplinary collaboration of clinicians with expertise in the management of MPE with the aim of producing a comprehensive review of the scientific literature.

Six areas of interest were identified, including the optimum management of symptomatic MPE, management of trapped lung in MPE, management of loculated MPE, prognostic factors in MPE, whether there is a role for oncological therapies prior to intervention for MPE and whether a histological diagnosis is always required in MPE.

The literature revealed that talc pleurodesis and indwelling pleural catheters effectively manage the symptoms of MPE. There was limited evidence regarding the management of trapped lung or loculated MPE. The LENT score was identified as a validated tool for predicting survival in MPE, with Brims' prognostic score demonstrating utility in mesothelioma prognostication. There was no evidence to support the use of oncological therapies as an alternative to MPE drainage, and the literature supported the use of tissue biopsy as the gold standard for diagnosis and treatment planning.

MicroRNA-625-3p promotes the proliferation, migration and invasion of thyroid cancer cells by up-regulating astrocyte elevated gene 1

BACKGROUND

Thyroid cancer is the most common malignancy in human endocrine system. This study aimed to investigate the effects of microRNA-625-3p (miR-625-3p) on thyroid cancer cell proliferation, migration, invasion and apoptosis, as well as underlying potential mechanism.

METHODS

The relative expressions of miR-625-3p in tumor tissues and adjacent normal tissues of 20 patients with papillary thyroid cancer (PTC) were assessed using qRT-PCR. Cell transfection was used to up-regulate or down-regulate the expressions of miR-625-3p in thyroid cancer SW579 and TPC-1 cells. Effects of miR-625-3p overexpression or suppression on SW579 and TPC-1 cell viability, migration, invasion and apoptosis were detected respectively. The regulatory effect of miR-625-3p on astrocyte elevated gene 1 (AEG-1) expression was also analyzed. Then, the roles of AEG-1 in SW579 and TPC-1 cell proliferation, migration, invasion and apoptosis, as well as Wnt/β-catenin and c-Jun N-terminal kinase (JNK) pathways activation, were evaluated.

RESULTS

miR-625-3p had high expressions in tumor tissues, compared to adjacent normal tissues. Overexpression of miR-625-3p significantly promoted SW579 and TPC-1 cell proliferation, migration and invasion but had no influence on cell apoptosis. Knockdown of miR-625-3p had opposite effects, but induced cell apoptosis. AEG-1 was up-regulated by miR-625-3p overexpression and participated in the effects of miR-625-3p on SW-579 and TPC-1 cells. In addition, overexpression of AEG-1 induced the activation of Wnt/β-catenin and JNK pathways in SW579 and TPC-1 cells.

CONCLUSION

miR-625-3p promoted proliferation, migration and invasion of thyroid cancer cells by enhancing the expression of AEG-1 and activating downstream Wnt/β-catenin and JNK pathways.