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

Exercise couples mitochondrial function with skeletal muscle fiber type via ROS-mediated epigenetic modification

Skeletal muscle is a heterogeneous tissue composed of different types of muscle fibers, demonstrating substantial plasticity. Physiological or pathological stimuli can induce transitions in muscle fiber types. However, the precise regulatory mechanisms behind these transitions remains unclear. This paper reviews the classification and characteristics of muscle fibers, along with the classical mechanisms of muscle fiber type transitions. Additionally, the role of exercise-induced muscle fiber type transitions in disease intervention is reviewed. Epigenetic pathways mediate cellular adaptations and thus represent potential targets for regulating muscle fiber type transitions. This paper focuses on the mechanisms by which epigenetic modifications couple mitochondrial function and contraction characteristics. Reactive Oxygen Species (ROS) are critical signaling regulators for the health-promoting effects of exercise. Finally, we discuss the role of exercise-induced ROS in regulating epigenetic modifications and the transition of muscle fiber types.

LncRNAs and related molecular basis in malignant pleural mesothelioma: challenges and potential

Malignant pleural mesothelioma (MPM) is a rare but invasive cancer, which mainly arises from mesothelial tissues of pleura, peritoneum and pericardium. Despite significant advances in treatments, the prognosis of MPM patients remains poor, and the 5-year survival rate is less than 10%. Therefore, it is urgent to explore novel therapeutic targets for the treatment of MPM. Growing evidence has indicated that long non-coding RNAs (lncRNAs) potentially could be promising therapeutic targets for numerous cancers. In this regard, lncRNAs might also potentially therapeutic targets for MPM. Recent advances have been made to investigate the molecular basis of MPM. This review first provides a comprehensive overview of roles of lncRNAs in MPM and then discusses the relationship between molecular basis of MPM and MPM-related lncRNAs to implement them as promising therapeutic targets for MPM.

MicroRNAs: a crossroad that connects obesity to immunity and aging

Obesity is characterized by an elevated amount of fat and energy storage in the adipose tissue (AT) and is believed to be the root cause of many metabolic diseases (MDs). Obesity is associated with low-grade chronic inflammation in AT. Like obesity, chronic inflammation and MDs are prevalent in the elderly. The resident immune microenvironment is not only responsible for maintaining AT homeostasis but also plays a crucial role in stemming obesity and related MDs. Mounting evidence suggests that obesity promotes activation in resident T cells and macrophages. Additionally, inflammatory subsets of T cells and macrophages accumulated into the AT in combination with other immune cells maintain low-grade chronic inflammation. microRNAs (miRs) are small non-coding RNAs and a crucial contributing factor in maintaining immune response and obesity in AT. AT resident T cells, macrophages and adipocytes secrete various miRs and communicate with other cells to create a potential effect in metabolic organ crosstalk. AT resident macrophages and T cells-associated miRs have a prominent role in regulating obesity by targeting several signaling pathways. Further, miRs also emerged as important regulators of cellular senescence and aging. To this end, a clear link between miRs and longevity has been demonstrated that implicates their role in regulating lifespan and the aging process. Hence, AT and circulating miRs can be used as diagnostic and therapeutic tools for obesity and related disorders. In this review, we discuss how miRs function as biomarkers and impact obesity, chronic inflammation, and aging.

Epigenetic Regulation in Chromium-, Nickel- and Cadmium-Induced Carcinogenesis

Environmental and occupational exposure to heavy metals, such as hexavalent chromium, nickel, and cadmium, are major health concerns worldwide. Some heavy metals are well-documented human carcinogens. Multiple mechanisms, including DNA damage, dysregulated gene expression, and aberrant cancer-related signaling, have been shown to contribute to metal-induced carcinogenesis. However, the molecular mechanisms accounting for heavy metal-induced carcinogenesis and angiogenesis are still not fully understood. In recent years, an increasing number of studies have indicated that in addition to genotoxicity and genetic mutations, epigenetic mechanisms play critical roles in metal-induced cancers. Epigenetics refers to the reversible modification of genomes without changing DNA sequences; epigenetic modifications generally involve DNA methylation, histone modification, chromatin remodeling, and non-coding RNAs. Epigenetic regulation is essential for maintaining normal gene expression patterns; the disruption of epigenetic modifications may lead to altered cellular function and even malignant transformation. Therefore, aberrant epigenetic modifications are widely involved in metal-induced cancer formation, development, and angiogenesis. Notably, the role of epigenetic mechanisms in heavy metal-induced carcinogenesis and angiogenesis remains largely unknown, and further studies are urgently required. In this review, we highlight the current advances in understanding the roles of epigenetic mechanisms in heavy metal-induced carcinogenesis, cancer progression, and angiogenesis.

Microbiomes, Epigenomics, Immune Response, and Splicing Signatures Interplay: Potential Use of Combination of Regulatory Pathways as Targets for Malignant Mesothelioma

Malignant mesotheliomas (MM) are hard to treat malignancies with poor prognosis and high mortality rates. This cancer is highly misdiagnosed in Sub-Saharan African countries. According to literature, the incidence of MM is likely to increase particularly in low-middle-income countries (LMICs). The burden of asbestos-induced diseases was estimated to be about 231,000 per annum. Lack of awareness and implementation of regulatory frameworks to control exposure to asbestos fibers contributes to the expected increase. Exposure to asbestos fibers can lead to cancer initiation by several mechanisms. Asbestos-induced epigenetic modifications of gene expression machinery and non-coding RNAs promote cancer initiation and progression. Furthermore, microbiome-epigenetic interactions control the innate and adaptive immunity causing exacerbation of cancer progression and therapeutic resistance. This review discusses epigenetic mechanisms with more focus on miRNAs and their interaction with the microbiome. The potential use of epigenetic alterations and microbiota as specific biomarkers to aid in the early detection and/or development of therapeutic targets is explored. The advancement of combinatorial therapies to prolong overall patient survival or possible eradication of MM especially if it is detected early is discussed.

MiR-30c-1-3p targets matrix metalloproteinase 9 involved in the rupture of abdominal aortic aneurysms

Abstract

Abdominal aortic aneurysm (AAA) can be fatal if ruptured, but there is no predictive biomarker. Our aim was to evaluate the prognostic potential of microRNAs (miRNAs/miRs) in an AAA mouse model and patients with unruptured AAA (URAAA) and ruptured AAA (RAAA). Among the 64 miRNAs differentially expressed in mice with AAA compared to control, miR-30c-1-3p, miR-432-3p, miR-3154, and miR-379-5p had high homology with human miRNAs. MiR-30c-1-3p plasma levels were significantly lower in patients with RAAA than in those with URAAA or control and tended to negatively correlate with the maximum aortic diameter (r =  −0.3153, P = 0.06109). MiR-30c-1-3p targeted matrix metalloproteinase (MMP)-9 mRNA through the coding region and downregulated its expression in vitro. MMP-9 plasma concentrations were significantly higher in the RAAA group than in the URAAA group (P < 0.001) and were negatively associated with miR-30c-1-3p levels (r =  −0.3671, P = 0.01981) and positively–with the maximal aortic diameter (r = 0.6251, P < 0.0001). The optimal cutoff values for MMP-9 expression and the maximal aortic diameter were 461.08 ng/ml and 55.95 mm, with areas under the curve of 0.816 and 0.844, respectively. Our results indicate that plasma levels of miR-30c-1-3p and MMP-9 may be candidate biomarkers of AAA progression.

Key messages

Downregulation of miR-30c-1-3p expression and upregulation of its potential target MMP-9 are predictors of the devastation of AAA.

Downregulation of miR-30c-1-3p expression and its downstream impact on MMP-9 have a potential on predicting the development and rupture of AAA.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00109-022-02230-2.

Impact of Exercise and Aging on Mitochondrial Homeostasis in Skeletal Muscle: Roles of ROS and Epigenetics

Aging causes degenerative changes such as epigenetic changes and mitochondrial dysfunction in skeletal muscle. Exercise can upregulate muscle mitochondrial homeostasis and enhance antioxidant capacity and represents an effective treatment to prevent muscle aging. Epigenetic changes such as DNA methylation, histone posttranslational modifications, and microRNA expression are involved in the regulation of exercise-induced adaptive changes in muscle mitochondria. Reactive oxygen species (ROS) play an important role in signaling molecules in exercise-induced muscle mitochondrial health benefits, and strong evidence emphasizes that exercise-induced ROS can regulate gene expression via epigenetic mechanisms. The majority of mitochondrial proteins are imported into mitochondria from the cytosol, so mitochondrial homeostasis is regulated by nuclear epigenetic mechanisms. Exercise can reverse aging-induced changes in myokine expression by modulating epigenetic mechanisms. In this review, we provide an overview of the role of exercise-generated ROS in the regulation of mitochondrial homeostasis mediated by epigenetic mechanisms. In addition, the potential epigenetic mechanisms involved in exercise-induced myokine expression are reviewed.

MicroRNA‑126 expression in the peripheral white blood cells of patients with breast and ovarian cancer is a potential biomarker for the early prediction of cancer risk in the carriers of methylated BRCA1

Constitutive breast cancer type 1 gene (BRCA1) promoter methylation is associated with increased cancer risk, but its role in cancer-free (CF) female carriers is incompletely understood. MicroRNA (miR) is modulated during early tumorigenesis. The present study assessed the modulation of miR-126 expression in the peripheral white blood cells (WBC) of patients with breast cancer (BC) and ovarian cancer (OC) as a biomarker of cancer risk in BRCA1 methylation carriers. A total of 1,114 female subjects [502 patients with BC, 187 patients with OC and 425 CF volunteers] were involved. Screening for BRCA1 promoter methylation in WBC was performed using the methylation–specific polymerase chain reaction (PCR) assay, BRCA1 mRNA was analyzed using a reverse transcription-quantitative PCR assay and miR-126 expression was analyzed using a stem-loop RT-qPCR assay. WBC BRCA1 promoter methylation status was significantly associated with OC (P=0.0266), early-onset BC (P=0.0003) and triple-negative BC (P=0.0066). Notably, 9.4% of the CF group exhibited WBC BRCA1 promoter methylation. In addition, high levels of miR-126 in WBCs were detected in all three groups. The increased level of miR-126 was significantly associated with a lower risk of distant metastasis (P=0.045) in BC, but a higher risk of disease progression and death (P=0.0029) in OC. There was a positive correlation between BRCA1 mRNA and miR-126 levels in the WBCs of all three groups, regardless of BRCA1 promoter methylation status. Notably, circulating miR-126 level was decreased in the BC and OC groups, but not in the CF group. Together, these results suggest the likely involvement of miR-126 in the constitutional methylation of BRCA1 promoter-related malignancies. Therefore, miR-126 may be a candidate biomarker for the early prediction of BC and OC risk in CF BRCA1 methylation carriers.

Micro-RNA-215 and -375 regulate thymidylate synthase protein expression in pleural mesothelioma and mediate epithelial to mesenchymal transition

The standard front-line treatment for pleural mesothelioma (PM) is pemetrexed-based chemotherapy, whose major target is thymidylate synthase (TS). In several cancer models, miR-215 and miR-375 have been shown to target TS, while information on these miRNAs in PM are still limited although suggest their role in epithelial to mesenchymal transition. Seventy-one consecutive PM tissues (4 biphasic, 7 sarcomatoid, and 60 epithelioid types) and 16 commercial and patient-derived PM cell lines were screened for TS, miR-215, and miR-375 expression. REN and 570B cells were selected for miR-215 and miR-375 transient transfections to test TS modulation. ZEB1 protein expression in tumor samples was also tested. Moreover, genetic profile was investigated by means of BAP1 and p53 immunohistochemistry. Expression of both miR-215 and miR-375 was significantly higher in epithelioid histotype. Furthermore, inverse correlation between TS protein and both miR-215 and miR-375 expression was found. Efficiently transfected REN and 570B cell lines overexpressing miR-215 and miR-375 showed decreased TS protein levels. Epithelioid PM with a mesenchymal component highlighted by reticulin stain showed significantly higher TS and ZEB1 protein and lower miRNA expression. A better survival was recorded for BAP1 lost/TS low cases. Our data indicate that miR-215 and miR-375 are involved in TS regulation as well as in epithelial-to-mesenchymal transition in PM.

Elucidating miRNA Function in Cancer Biology via the Molecular Genetics' Toolbox

Micro-RNA (miRNAs) are short non-coding RNAs of about 18-20 nucleotides in length and are implicated in many cellular processes including proliferation, development, differentiation, apoptosis and cell signaling. Furthermore, it is well known that miRNA expression is frequently dysregulated in many cancers. Therefore, this review will highlight the various mechanisms by which microRNAs are dysregulated in cancer. Further highlights include the abundance of molecular genetics tools that are currently available to study miRNA function as well as their advantages and disadvantages with a special focus on various CRISPR/Cas systems This review provides general workflows and some practical considerations when studying miRNA function thus enabling researchers to make informed decisions in regards to the appropriate molecular genetics tool to be utilized for their experiments.

The Role of microRNA in the Inflammatory Response of Wound Healing

Wound healing, a highly complex pathophysiological response to injury, includes four overlapping phases of hemostasis, inflammation, proliferation, and remodeling. Initiation and resolution of the inflammatory response are the primary requirements for wound healing, and are also key events that determines wound quality and healing time. Currently, the number of patients with persistent chronic wounds has generally increased, which imposes health and economic burden on patients and society. Recent studies have found that microRNA(miRNA) plays an essential role in the inflammation involved in wound healing and may provide a new therapeutic direction for wound treatment. Therefore, this review focused on the role and significance of miRNA in the inflammation phase of wound healing.

Epigenetic modifications from arsenic exposure: A comprehensive review

Arsenic is a notorious element with the potential to harm exposed individuals in ways that include cancerous and non-cancerous health complications. Millions of people across the globe (especially in South and Southeast Asian countries including China, Vietnam, India and Bangladesh) are currently being unknowingly exposed to precarious levels of arsenic. Among the diverse effects associated with such arsenic levels of exposure is the propensity to alter the epigenome. Although a large volume of literature exists on arsenic-induced genotoxicity, cytotoxicity, and inter-individual susceptibility due to active research on these subject areas from the last millennial, it is only recently that attention has turned on the ramifications and mechanisms of arsenic-induced epigenetic changes. The present review summarizes the possible mechanisms involved in arsenic induced epigenetic alterations. It focuses on the mechanisms underlying epigenome reprogramming from arsenic exposure that result in improper cell signaling and dysfunction of various epigenetic components. The mechanistic information articulated from the review is used to propose a number of novel therapeutic strategies with a potential for ameliorating the burden of worldwide arsenic poisoning.

Towards an integrative understanding of cancer mechanobiology: calcium, YAP, and microRNA under biophysical forces

An increasing number of studies have demonstrated the significant roles of the interplay between microenvironmental mechanics in tissues and biochemical-genetic activities in resident tumor cells at different stages of tumor progression. Mediated by molecular mechano-sensors or -transducers, biomechanical cues in tissue microenvironments are transmitted into the tumor cells and regulate biochemical responses and gene expression through mechanotransduction processes. However, the molecular interplay between the mechanotransduction processes and intracellular biochemical signaling pathways remains elusive. This paper reviews the recent advances in understanding the crosstalk between biomechanical cues and three critical biochemical effectors during tumor progression: calcium ions (Ca²⁺), yes-associated protein (YAP), and microRNAs (miRNAs). We address the molecular mechanisms underpinning the interplay between the mechanotransduction pathways and each of the three effectors. Furthermore, we discuss the functional interactions among the three effectors in the context of soft matter and mechanobiology. We conclude by proposing future directions on studying the tumor mechanobiology that can employ Ca²⁺, YAP, and miRNAs as novel strategies for cancer mechanotheraputics. This framework has the potential to bring insights into the development of novel next-generation cancer therapies to suppress and treat tumors.

N-acetyl l-aspartate and Triacetin modulate tumor suppressor MicroRNA and class I and II HDAC gene expression induce apoptosis in Glioblastoma cancer cells in vitro

Glioblastoma multiforme (GBM), grade IV glioma and is aggressive, malignant primary brain cancer. Altered expression and activity of epigenetic proteins such as histone deacetylases (HDACs) are involved in GBM metastasis. Also, acetates are important to brain metabolites that regulate cell proliferation and apoptosis. Here, we have examined the effect of the acetates on the cell-cycle. U87MG cancer cells treated with N-acetyl l-aspartate (NAA) and sodium acetate have exhibited G1 phase cell-cycle arrest whereas U87MG cells treated with Triacetin (TA), and potassium acetate has induced G2/M cell cycle arrest. We have observed inhibition of histone deacetylase (HDAC) mRNA levels in acetate treated U87MG cells. Interestingly, acetates-treated U87MG cells have shown a significant reduction in the mRNA level of class II HDACs than class I HDACs. Acetate treated cells have exhibited an enhanced expression of various microRNAs such as miR-15b, miR-92, miR-101, miR-155, miR-199, miR-200, miR-223, miR-16, and miR-17 that are involved in the inhibition of cancer cell proliferation, invasion, migration, and angiogenesis. Further, these acetate molecules regulate genes involved in mammalian target of rapamycin complex 2 (mTORC2) such as mammalian stress-activated protein kinase-interacting protein (mSIN1), protein observed with Rictor 2 (Protor 2), and protein kinase C α (PKCα). The present study reveals the possible involvement of the mTORC2 complex during acetate-mediated HDAC inhibition, as well as microRNA modulation. Furthermore, molecular modeling studies were employed to understand the binding mode of these acetate molecules to mTOR, Rapamycin-insensitive companion of mammalian target of rapamycin (Rictor), and HDAC-8 proteins. Thus in this study, we have identified the pivotal role of acetates in the modulation of mTOR complex, epigenetic genes and provide structural as well as functional insights that will help in future drug discovery against GBM cancer therapy.

Breast Cancer CAFs: Spectrum of Phenotypes and Promising Targeting Avenues

Activationof the tumor-associated stroma to support tumor growth is a common feature observed in different cancer entities. This principle is exemplified by cancer-associated fibroblasts (CAFs), which are educated by the tumor to shape its development across all stages. CAFs can alter the extracellular matrix (ECM) and secrete a variety of different molecules. In that manner they have the capability to affect activation, survival, proliferation, and migration of other stromal cells and cancer cell themselves. Alteration of the ECM, desmoplasia, is a common feature of breast cancer, indicating a prominent role for CAFs in shaping tumor development in the mammary gland. In this review, we summarize the multiple roles CAFs play in mammary carcinoma. We discuss experimental and clinical strategies to interfere with CAFs function in breast cancer. Moreover, we highlight the issues arising from CAFs heterogeneity and the need for further research to identify CAFs subpopulation(s) that can be targeted to improve breast cancer therapy.

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.

HIV-1 Tat and cocaine impact astrocytic energy reservoir influence on miRNA epigenetic regulation

Astrocytes are the primary regulator of energy metabolism in the central nervous system (CNS), and impairment of astrocyte's energy resource may trigger neurodegeneration. HIV infections and cocaine use are known to alter epigenetic modification, including miRNAs, which can target gene expression post-transcriptionally. However, miRNA-mediated astrocyte energy metabolism has not been delineated in HIV infection and cocaine abuse. Using next-generation sequencing (NGS), we identified a total of 1900 miRNAs, 64 were upregulated and 68 miRNAs were downregulated in the astrocytes by HIV-1 Tat with cocaine exposure. Moreover, miR-4727-3p, miR-5189-5p, miR-5090, and miR-6810-5p expressions were significantly impacted, and their gene targets were identified as VAMP2, NFIB, PPM1H, MEIS1, and PSD93 through the bioinformatic approach. In addition, the astrocytes treated with the nootropic drug piracetam protects these miRNAs. These findings provide evidence that the miRNAs in the astrocytes may be a potential biomarker and therapeutic target for HIV and cocaine abuse-induced neurodegeneration.

Overexpression of microRNA‑486 affects the proliferation and chemosensitivity of mesothelioma cell lines by targeting PIM1

Dysregulated levels of microRNAs (miRNAs or miRs), involved in oncogenic pathways, have been proposed to contribute to the aggressiveness of malignant pleural mesothelioma (MPM). Previous studies have highlighted the downregulation of miRNA miR-486-5p in patients with mesothelioma and the introduction of miRNA mimics to restore their reduced or absent functionality in cancer cells is considered an important therapeutic strategy. The aim of the present study was to evaluate the mechanisms through which miRNAs may influence the functions, proliferation and sensitivity to cisplatin of MPM cells. In the present study, a miR-486-5p mimic was transfected into the H2052 and H28 MPM cell lines, and cell viability, proliferation, apoptosis and mitochondrial membrane potential were monitored. miR-486-5p overexpression led to a clear impairment of cell proliferation, targeting CDK4 and attenuating cell cycle progression. In addition, transfection with miR-486-5p mimic negatively regulated the release of inflammatory factors and the expression of Provirus integration site for Moloney murine leukaemia virus 1 (PIM1). The sensitivity of the cells to cisplatin was enhanced by enhancing the apoptotic effects of the drug and impairing mitochondrial function. On the whole, the present study demonstrates that miR-486-5p may play an important role in MPM treatment by targeting multiple pathways involved in tumour development and progression. These activities may be mostly related to the downregulation of PIM1, a crucial regulator of cell survival and proliferation. Furthermore, these results provide support for the combined use of miR-486-5p with chemotherapy as a therapeutic strategy for MPM.

Role of p53-miRNAs circuitry in immune surveillance and cancer development: A potential avenue for therapeutic intervention

The genome's guardian, p53, is a master regulatory transcription factor that occupies sequence-specific response elements in many genes and modulates their expression. The target genes transcribe both coding RNA and non-coding RNA involved in regulating several biological processes such as cell division, differentiation, and cell death. Besides, p53 also regulates tumor immunology via regulating the molecules related to the immune response either directly or via regulating other molecules, including microRNAs (miRNAs). At the post-transcriptional level, the regulations of genes by miRNAs have been an emerging mechanism. Interestingly, p53 and various miRNAs cross-talk at different regulation levels. The cross-talk between p53 and miRNAs creates loops, turns, and networks that can influence cell metabolism, cell fate, cellular homeostasis, and tumor formation. Further, p53-miRNAs circuit has also been insinuated in the regulation of immune surveillance machinery. There are several examples of p53-miRNAs circuitry where p53 regulates immunomodulatory miRNA expression, such as miR-34a and miR-17-92. Similarly, a reverse process occurs in which miRNAs such as miR-125b and miR-let-7 regulate the expression of p53. Thus, the p53-miRNAs circuitry connects the immunomodulatory pathways and may shift the pro-inflammatory balance towards the pro-tumorigenic condition. In this review, we discuss the influence of p53-miRNAs circuitry in modulating the immune response in cancer development. We assume that thorough studies on the p53-miRNAs circuitry in various cancers may prove useful in developing effective new cancer therapeutics for successfully combating this disease.

Noncoding RNAs: Regulatory Molecules of Host-Microbiome Crosstalk

Recent emerging evidence has revealed that regulatory noncoding RNAs (microRNAs, circular RNAs) modulate host-microbe interactions and they have been proposed as potential biomarkers of the host's response to microbiome-linked pathologies such as cancers, obesity, and neurodegenerative diseases. Interactions between microRNAs and circular RNAs, however, increase the complexity of the mechanisms that modulate host-microbe interactions. Current knowledge on these noncoding RNAs (ncRNAs) is mainly generated from well controlled germ-free or knockout (small) animal models. Application of such knowledge to effective modulation outcomes in humans (and livestock) is challenging due to the complex nature of microbiome-linked pathologies in larger outbred animals that constantly interact with the changing environment. This review critically discusses the findings of regulatory noncoding RNAs and their roles in microbiome-linked pathologies in small and large animals and provides insights on their roles as potential therapeutic agents to improve human (and livestock) health.

Circ_0001175 Promotes Hepatocellular Carcinoma Cell Proliferation and Metastasis by Regulating miR-130a-5p

Objective

Many aberrantly expressed circular RNAs (circRNAs) play important roles in the development and progression of hepatocellular carcinoma (HCC). However, the exact function of circ_0001175 in HCC cells is unknown. Our study aimed to investigate the expression characteristics of circ_0001175 in HCC and its effects on the proliferation, migration and invasion of HCC cells, and to explore the potential mechanism.

Materials and Methods

Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot were carried out to detect circ_0001175, microRNA-130a-5p (miR-130a-5p) and sorting nexin 5 (SNX5) expressions in HCC tissues and cells; cell counting kit-8 (CCK-8), BrdU and Transwell assays were conducted to detect the proliferation, migration and invasion of HCC cells. A lung metastasis model in nude mice was used to examine the effect of circ_0001175 on the metastasis of HCC cells in vivo. Bioinformatics prediction, luciferase reporter gene experiment, Ago2-RIP experiment and RNA pull-down assay were adopted to identify the binding relationships among circ_0001175, miR-130a-5p and SNX5.

Results

Circ_0001175 and SNX5 expressions were up-regulated in HCC tissues and cell lines, while miR-130a-5p expression was down-regulated. Abnormal expressions of circ_0001175, miR-130a-5p and SNX5 were associated with poor clinicopathological features of HCC patients; circ_0001175 facilitated HCC cell proliferation, migration and invasion in vitro and promoted lung metastasis in vivo; miR-130a-5p inhibited the above malignant biological behaviors of HCC cells, and it could reverse the function of circ_0001175. SNX5 was identified as a target gene of miR-130a-5p, and circ_0001175 could sponge miR-130a-5p and up-regulate the expression of SNX5 in HCC cells.

Conclusion

Circ_0001175 is highly expressed in HCC and facilitates HCC progression through regulating miR-130a-5p/SNX5 axis.

A comparison between the effects of over-expression of miRNA-16 and miRNA-34a on cell cycle progression of mesothelioma cell lines and on their cisplatin sensitivity

The prognosis of patients affected by malignant pleural mesothelioma (MPM) is presently poor and no therapeutic strategies have improved their survival yet. Introduction of miRNA mimics to restore their reduced or absent functionality in cancer cells is considered an important opportunity and a combination of miR's might be even more effective. In the present study, miR-16 and miR-34a were transfected, singularly and in combination, in MPM cell lines H2052 and H28, and their effects on cell proliferation and sensitivity to cisplatin are reported. Interestingly, the overexpression of both miRs, alone or combined, slows down the cell cycle progression, modulates the p53 and HMGB1 expression and increases the sensitivity of cells to cisplatin, producing a marked impairment of cell proliferation and strengthening the apoptotic effect of the drug. However, the co-overexpression of the two miRs results more effective only in the regulation of the cell cycle, but does not enhance the sensitivity of MPM cells to cisplatin. Consequently, although the potential of miR-16 and miR-34a is confirmed, we must conclude that their combination does not improve the response of MPM to chemotherapy.

Bioinformatics analysis to determine the prognostic value and prospective pathway signaling of miR-126 in non-small cell lung cancer

Background

MicroRNAs (miRNAs) have been demonstrated to play crucial roles in the initiation and development of non-small cell lung cancer (NSCLC). However, further investigation of the specific role of miR-126 in NSCLC is still required.

Methods

An analysis of miR-126 expression in NSCLC was carried out using the Gene Expression Omnibus (GEO) database, and a literature review was also performed. The differentially expressed genes (DEGs) in three mRNA datasets, GSE18842, GSE19804, and GSE101929, from GEO were identified. Following the prediction of hsa-miR-126-5p target genes by TargetScan, the overlap of miR-126 target genes with DEGs in NSCLC was examined. After that, Gene Ontology enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analyses were performed. Finally, an analysis to identify the impact of hub genes on the prognosis of NSCLC was carried out on the basis of a protein-protein interaction (PPI) network constructed using STRING and Cytoscape.

Results

The data in the literature review revealed a trend that miR126 was downregulated in NSCLC. The number of both NSCLC-related and miR-126-related DEGs was 187. Dozens of DEGs were significantly enriched in biological regulation, cell membrane binding, and signal receptor binding. In the PPI network analysis, 3 of 10 identified hub genes, namely NCAPG, MELK, and KIAA0101, were obviously related to poor prognosis in NSCLC; the survival rate was low among patients with high expression levels of these genes. Furthermore, through network analysis, TPX2, HMMR, and ANLN were identified as recessive miR-126-related genes that may be involved in NSCLC.

Conclusions

MiR-126 plays an essential role in the biological processes of NSCLC through binding to target genes and influences the prognosis of patients with the disease.

microRNAs Biogenesis, Functions and Role in Tumor Angiogenesis

microRNAs (miRNAs) are small non-coding RNA molecules, evolutionary conserved. They target more than one mRNAs, thus influencing multiple molecular pathways, but also mRNAs may bind to a variety of miRNAs, either simultaneously or in a context-dependent manner. miRNAs biogenesis, including miRNA transcription, processing by Drosha and Dicer, transportation, RISC biding, and miRNA decay, are finely controlled in space and time. miRNAs are critical regulators in various biological processes, such as differentiation, proliferation, apoptosis, and development in both health and disease. Their dysregulation is involved in tumor initiation and progression. In tumors, they can act as onco-miRNAs or oncosuppressor-miRNA participating in distinct cellular pathways, and the same miRNA can perform both activities depending on the context. In tumor progression, the angiogenic switch is fundamental. miRNAs derived from tumor cells, endothelial cells, and cells of the surrounding microenvironment regulate tumor angiogenesis, acting as pro-angiomiR or anti-angiomiR. In this review, we described miRNA biogenesis and function, and we update the non-classical aspects of them. The most recent role in the nucleus, as transcriptional gene regulators and the different mechanisms by which they could be dysregulated, in tumor initiation and progression, are treated. In particular, we describe the role of miRNAs in sprouting angiogenesis, vessel co-option, and vasculogenic mimicry. The role of miRNAs in lymphoma angiogenesis is also discussed despite the scarcity of data. The information presented in this review reveals the need to do much more to discover the complete miRNA network regulating angiogenesis, not only using high-throughput computational analysis approaches but also morphological ones.

Mechanistic Actions of microRNAs in Diabetic Wound Healing

Wound healing is a complex biological process that is impaired under diabetes conditions. Chronic non-healing wounds in diabetes are some of the most expensive healthcare expenditures worldwide. Early diagnosis and efficacious treatment strategies are needed. microRNAs (miRNAs), a class of 18-25 nucleotide long RNAs, are important regulatory molecules involved in gene expression regulation and in the repression of translation, controlling protein expression in health and disease. Recently, miRNAs have emerged as critical players in impaired wound healing and could be targets for potential therapies for non-healing wounds. Here, we review and discuss the mechanistic background of miRNA actions in chronic wounds that can shed the light on their utilization as specific wound healing biomarkers.

The Molecular Basis of Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is a rare, aggressive malignancy of the pleural lining associated with asbestos exposure in greater than 80% of cases. It is characterized by molecular heterogeneity both between patients and within individual tumors. Next-generation sequencing technology and novel computational techniques have resulted in a greater understanding of the epigenetic, genetic, and transcriptomic hallmarks of MPM. This article reviews these features and discusses the implications of advances in MPM molecular biology in clinical practice.

Understanding the Mechanisms by Which Epigenetic Modifiers Avert Therapy Resistance in Cancer

The development of resistance to anti-cancer therapeutics remains one of the core issues preventing the improvement of survival rates in cancer. Therapy resistance can arise in a multitude of ways, including the accumulation of epigenetic alterations in cancer cells. By remodeling DNA methylation patterns or modifying histone proteins during oncogenesis, cancer cells reorient their epigenomic landscapes in order to aggressively resist anti-cancer therapy. To combat these chemoresistant effects, epigenetic modifiers such as DNA hypomethylating agents, histone deacetylase inhibitors, histone demethylase inhibitors, along with others have been used. While these modifiers have achieved moderate success when used either alone or in combination with one another, the most positive outcomes were achieved when they were used in conjunction with conventional anti-cancer therapies. Epigenome modifying drugs have succeeded in sensitizing cancer cells to anti-cancer therapy via a variety of mechanisms: disrupting pro-survival/anti-apoptotic signaling, restoring cell cycle control and preventing DNA damage repair, suppressing immune system evasion, regulating altered metabolism, disengaging pro-survival microenvironmental interactions and increasing protein expression for targeted therapies. In this review, we explore different mechanisms by which epigenetic modifiers induce sensitivity to anti-cancer therapies and encourage the further identification of the specific genes involved with sensitization to facilitate development of clinical trials.

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.

Mechanism of miR-222 and miR-126 regulation and its role in asbestos-induced malignancy

MiR-222 and miR-126 are associated with asbestos exposure and the ensuing malignancy, but the mechanism(s) of their regulation remain unclear. We evaluated the mechanism by which asbestos regulates miR-222 and miR-126 expression in the context of cancer etiology. An 'in vitro' model of carcinogen-induced cell transformation was used based on exposing bronchial epithelium BEAS-2B cells to three different carcinogens including asbestos. Involvement of the EGFR pathway and the role of epigenetics have been investigated in carcinogen-transformed cells and in malignant mesothelioma, a neoplastic disease associated with asbestos exposure. Increased expression of miR-222 and miR-126 were found in asbestos-transformed cells, but not in cells exposed to arsenic and chrome. Asbestos-mediated activation of the EGFR pathway and macrophages-induced inflammation resulted in miR-222 upregulation, which was reversed by EGFR inhibition. Conversely, asbestos-induced miR-126 expression was affected neither by EGFR modulation nor inflammation. Rather than methylation of the miR-126 host gene EGFL7, epigenetic mechanism involving DNMT1- and PARP1-mediated chromatin remodeling was found to upregulate of miR-126 in asbestos-exposed cells, while miR-126 was downregulated in malignant cells. Analysis of MM tissue supported the role of PARP1 in miR-126 regulation. Therefore, activation of the EGFR pathway and the PARP1-mediated epigenetic regulation both play a role in asbestos-induced miRNA expression, associated with in asbestos-induced carcinogenesis and tumor progression.