MicroRNA-21 regulates the ERK/NF-κB signaling pathway to affect the proliferation, migration, and apoptosis of human melanoma A375 cells by targeting SPRY1, PDCD4, and PTEN

The regulatory mechanisms of oncomiRs in cancer

Cancer development is a complex process that primarily results from the combination of genetic alterations and the dysregulation of major signalling pathways due to interference with the epigenetic machinery. As major epigenetic regulators, miRNAs are central players in the control of many key tumour development factors. These miRNAs have been classified as oncogenic miRNAs (oncomiRs) when they target tumour suppressor genes and tumour suppressor miRNAs (TS miRNAs) when they inhibit oncogene protein expression. Most of the mechanisms that modulate oncomiR expression are linked to transcriptional or posttranscriptional regulation. However, non-transcriptional processes, such as gene amplification, have been described as alternative processes that are responsible for increasing oncomiR expression. The current review summarises the different mechanisms controlling the upregulation of oncomiR expression in cancer cells and the tumour microenvironment (TME). Detailed knowledge of the mechanism underlying the regulation of oncomiR expression in cancer may pave the way for understanding the critical role of oncomiRs in cancer development and progression.

Dpep Inhibits Cancer Cell Growth and Survival via Shared and Context-Dependent Transcriptome Perturbations

Dpep is a cell-penetrating peptide targeting transcription factors ATF5, CEBPB, and CEBPD, and that selectively promotes the apoptotic death of multiple tumor cell types in vitro and in vivo. As such, it is a potential therapeutic. To better understand its mechanism of action, we used PLATE-seq to compare the transcriptomes of six cancer cell lines of diverse origins before and after Dpep exposure. This revealed a context-dependent pattern of regulated genes that was unique to each line, but that exhibited a number of elements that were shared with other lines. This included the upregulation of pro-apoptotic genes and tumor suppressors as well as the enrichment of genes associated with responses to hypoxia and interferons. Downregulated transcripts included oncogenes and dependency genes, as well as enriched genes associated with different phases of the cell cycle and with DNA repair. In each case, such changes have the potential to lie upstream of apoptotic cell death. We also detected the regulation of unique as well as shared sets of transcription factors in each line, suggesting that Dpep may initiate a cascade of transcriptional responses that culminate in cancer cell death. Such death thus appears to reflect context-dependent, yet shared, disruption of multiple cellular pathways as well as of individual survival-relevant genes.

Role of midazolam on cancer progression/survival - An updated systematic review

Background and Aims

Cancer is a leading cause of mortality worldwide. Despite advancements in cancer management, cancer progression remains a challenge, requiring the development of novel therapies. Midazolam is a commonly used adjunct to anaesthesia care for various surgeries, including cancer. Recently, there has been a growing interest in exploring the potential role of midazolam as an anticancer agent; however, the exact mechanism of this linkage is yet to be investigated thoroughly.

Methods

Based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline, this systematic review presented aggregated evidence (till November 2022) of the effects of midazolam on cancer progression and survival. All primary research article types where midazolam was administered in vivo or in vitro on subjects with cancers were included. No restrictions were applied on routes of administration or the type of cancer under investigation. Narrative synthesis depicted qualitative findings, whereas frequencies and percentages presented numerical data.

Results

Of 1720 citations, 19 studies were included in this review. All articles were preclinical studies conducted either in vitro (58%, 11/19) or both in vivo and in vitro (42%, 8/19). The most studied cancer was lung carcinoma (21%, 4/19). There are two main findings in this review. First, midazolam delays cancer progression (89%, 17/19). Second, midazolam reduces cancer cell survival (63%, 12/19). The two major mechanisms of these properties can be explained via inducing apoptosis (63%, 12/19) and inhibiting cancer cell proliferation (53%, 10/19). In addition, midazolam demonstrated antimetastatic properties via inhibition of cancer invasion (21%, 4/19), migration (26%, 5/19), or epithelial-mesenchymal transition (5%, 1/19). These anticancer properties of midazolam were demonstrated through different pathways when midazolam was used alone or in combination with traditional cancer chemotherapeutic agents.

Conclusion

This systematic review highlights that midazolam has the potential to impede cancer progression and decrease cancer cell survival. Extrapolation of these results into human cancer necessitates further investigation.

Expression and Regulatory Mechanisms of MicroRNA in Cholesteatoma: A Systematic Review

Cholesteatoma is a temporal bone disease characterized by dysfunctions of keratinocytes. MicroRNAs (miRNAs) are evolutionary conserved noncoding RNAs that regulate mRNA expression. They can be packaged into exosomes and transported to target cells that can be used in the future therapy of cholesteatoma. This study aimed to collect knowledge on the role of miRNAs and exosomal miRNAs in cholesteatoma and was conducted according to the PRISMA guidelines for systematic reviews. Four databases were screened: Pubmed/MEDLINE, Web of Science, Scopus, and the Cochrane Library. The last search was run on the 6th of June 2023. We included full-text original studies written in English, which examined miRNAs in cholesteatoma. The risk of bias was assessed using the Office of Health Assessment and Translation (OHAT) Risk of Bias Rating Tool, modified for the needs of this review. We identified 118 records and included 18 articles. Analyses revealed the downregulation of exosomal miR-17 as well as miR-10a-5p, miR-125b, miR-142-5p, miR34a, miR-203a, and miR-152-5p and the overexpression of exosomal miR-106b-5p as well as miR-1297, miR-26a-5p, miR-199a, miR-508-3p, miR-21-3p, miR-584-5p, and miR-16-1-3p in cholesteatoma. The role of differentially expressed miRNAs in cholesteatoma, including cell proliferation, apoptosis, the cell cycle, differentiation, bone resorption, and the remodeling process, was confirmed, making them a potential therapeutic target in this disease.

miRNAs as potential game-changers in melanoma: A comprehensive review

Melanoma is the sixth most frequent malignancy. It represents 1.7% of all cancer cases worldwide. Many risk factors are associated with melanoma including ultraviolet radiation skin phenotype, Pigmented Nevi, Pesticides, and genetic and epigenetic factors. Of the main epigenetic factors affecting melanoma are microribonucleic acids (miRNAs). They are short nucleic acid chains that have the potential to prevent the expression of a number of target genes. They could target a number of genes related to melanoma initiation, stemness, angiogenesis, apoptosis, proliferation, and potential resistance to treatment. Additionally, they can control several melanoma signaling pathways, including P53, WNT/-catenin, JAK/STAT, PI3K/AKT/mTOR axis, TGF- β, and EGFR. MiRNAs also play a role in the resistance of melanoma to essential treatment regimens. The stability and abundance of miRNAs might be important factors enhancing the use of miRNAs as markers of prognosis, diagnosis, stemness, survival, and metastasis in melanoma patients.

Knockdown of miR-150-5p reduces hypoxia-induced autophagy and epithelial-mesenchymal transition of endometriotic cells via regulating the PDCD4/NF-κB signaling pathway

BACKGROUND

Hypoxia is an important microenvironmental factor that induces Endometriosis (EMs), but its mechanism remains unclear. Our study aims to investigate the mechanisms of miR-150-5p on hypoxia-induced EMs.

METHODS

Ovarian endometriosis cyst wall stromal cell lines CRL-7566 cells were treated with hypoxia. Cell migration ability was measured by Transwell assay. qRT-PCR was performed to detect miR-150-5p and PDCD4 expression. The autophagy-related proteins (LC3-I, LC3-II, Beclin-1, and p62), epithelial-mesenchymal transition (EMT) related proteins (E-cadherin, N-cadherin, and Vimentin) and NF-κB signaling pathway related proteins p65 expression were measured by western blot. Dual-luciferase reporter gene assay verified the binding relationship between miR-150-5p and PDCD4.

RESULTS

After hypoxia treatment, the miR-150-5p expression was up-regulated in CRL-7566 cells, while the expression of PDCD4 was down-regulated. In CRL-7566 cells, autophagy, migration and EMT were increased after hypoxia treatment. The autophagy inhibitor 3-MA inhibited hypoxia-induced the autophagy, migration and EMT of CRL-7566 cells. Hypoxia-induced autophagy and EMT of CRL-7566 cells were inhibited after knocking down miR-150-5p. Then miR-150-5p negatively regulated PDCD4 expression. PDCD4 knockdown reversed the inhibitory effect of miR-150-5p silencing on hypoxia-induced autophagy and EMT of CRL-7566 cells. Inhibiting the NF-κB signaling pathway weakened the effect of PDCD4 knockdown on hypoxia-induced autophagy and EMT of CRL-7566 cells.

CONCLUSION

MiR-150-5p silencing inhibited hypoxia-induced autophagy and EMT of endometriotic cells by regulating the PDCD4/NF-κB signaling pathway.

Targeting the epigenome in malignant melanoma: Facts, challenges and therapeutic promises

Malignant melanoma is the most lethal type of skin cancer with high rates of mortality. Although current treatment options provide a short-clinical benefit, acquired-drug resistance highlights the low 5-year survival rate among patients with advanced stage of the disease. In parallel, the involvement of an aberrant epigenetic landscape, (e.g., alterations in DNA methylation patterns, histone modifications marks and expression of non-coding RNAs), in addition to the genetic background, has been also associated with the onset and progression of melanoma. In this review article, we report on current therapeutic options in melanoma treatment with a focus on distinct epigenetic alterations and how their reversal, by specific drug compounds, can restore a normal phenotype. In particular, we concentrate on how single and/or combinatorial therapeutic approaches have utilized epigenetic drug compounds in being effective against malignant melanoma. Finally, the role of deregulated epigenetic mechanisms in promoting drug resistance to targeted therapies and immune checkpoint inhibitors is presented leading to the development of newly synthesized and/or improved drug compounds capable of targeting the epigenome of malignant melanoma.

Single Shot vs. Cocktail: A Comparison of Mono- and Combinative Application of miRNA-Targeted Mesyl Oligonucleotides for Efficient Antitumor Therapy

Simple Summary

Current approaches to the treatment of oncological diseases are still suffering from a lack of efficiency and selectivity and are accompanied by pronounced non-specific toxic effects. This study evaluated the antitumor potential of highly selective multitarget antisense downregulation of small non-coding RNA molecules—microRNAs—where dysregulation in cells frequently triggers oncotransformation and tumor development. We report herein that combinations of recently developed mesyl phosphoramidate oligonucleotides, targeted to multifunctional miRNA regulators miR-17, miR-21 and miR-155, exhibited potent synergistic antiproliferative and antimigrative effects on highly aggressive tumor cells. Furthermore, the significant antitumor activity of a cocktail of three antisense oligonucleotides targeted to miR-21, miR-17, and miR-155 almost completely suppressed lymphosarcoma RLS₄₀ tumor growth and exerted prominent antimetastatic effects in a melanoma B16 model. Such treatment elicited no sign of in vivo toxicity and even exhibited remedial effects on the liver of tumor-bearing mice.

Abstract

Rational combinations of sequence-specific inhibitors of pro-oncogenic miRNAs can efficiently interfere with specific tumor survival pathways, offering great promise for targeted therapy of oncological diseases. Herein, we uncovered the potential of multicomponent therapy by double or triple combinations of highly potent mesyl phosphoramidate (µ) antisense oligodeoxynucleotides targeted to three proven pro-oncogenic microRNAs—miR-17, miR-21, and miR-155. A strong synergism in the inhibition of proliferation and migration of B16 melanoma cells was demonstrated in vitro for pairs of µ-oligonucleotides, which resulted in vivo in profound inhibition (up to 85%) of lung metastases development after intravenous injection of µ-oligonucleotide-transfected B16 cells in mice. A clear benefit of µ-21-ON/µ-17-ON and µ-17-ON/µ-155-ON/µ-21-ON combination antitumor therapy was shown for the lymphosarcoma RLS₄₀ solid tumor model. In vivo administration of the µ-17-ON/µ-155-ON/µ-21-ON cocktail into RLS₄₀-bearing mice elicited fourfold delay of tumor growth as a result of strong inhibition of tumor mitotic activity. It was discovered that the cocktail of µ-21-ON/µ-17-ON/µ-155-ON led to a twofold decrease in total destructive changes in murine liver, which indicates both the reduction in toxic tumor burden and the absence of specific toxicity of the proposed therapy.

Nanoparticle delivery of miR-21-3p sensitizes melanoma to anti-PD-1 immunotherapy by promoting ferroptosis

Background

Although anti-programmed cell death protein 1 (PD-1) immunotherapy is greatly effective in melanoma treatment, low response rate and treatment resistance significantly hinder its efficacy. Tumor cell ferroptosis triggered by interferon (IFN)-γ that is derived from tumor-infiltrating CD8⁺ T cells greatly contributes to the effect of immunotherapy. However, the molecular mechanism underlying IFN-γ-mediated ferroptosis and related potentially promising therapeutic strategy warrant further clarification. MicroRNAs (miRNAs) participate in ferroptosis execution and can be delivered systemically by multiple carriers, which have manifested obvious therapeutic effects on cancer.

Methods

MiRNAs expression profile in IFN-γ-driven ferroptosis was obtained by RNA sequencing. Biochemical assays were used to clarify the role of miR-21-3p in IFN-γ-driven ferroptosis and the underlying mechanism. MiR-21-3p-loaded gold nanoparticles were constructed and systemically applied to analyze the role of miR-21-3p in anti-PD-1 immunotherapy in preclinical transplanted tumor model.

Results

MiRNAs expression profile of melanoma cells in IFN-γ-driven ferroptosis was first obtained. Then, upregulated miR-21-3p was proved to facilitate IFN-γ-mediated ferroptosis by potentiating lipid peroxidation. miR-21-3p increased the ferroptosis sensitivity by directly targeting thioredoxin reductase 1 (TXNRD1) to enhance lipid reactive oxygen species (ROS) generation. Furthermore, miR-21-3p overexpression in tumor synergized with anti-PD-1 antibody by promoting tumor cell ferroptosis. More importantly, miR-21-3p-loaded gold nanoparticles were constructed, and the systemic delivery of them increased the efficacy of anti-PD-1 antibody without prominent side effects in preclinical mice model. Ultimately, ATF3 was found to promote miR-21-3p transcription in IFN-γ-driven ferroptosis.

Conclusions

MiR-21–3 p upregulation contributes to IFN-γ-driven ferroptosis and synergizes with anti-PD-1 antibody. Nanoparticle delivery of miR-21–3 p is a promising therapeutic approach to increase immunotherapy efficacy without obvious systemic side effects.

Midazolam Suppresses Hepatocellular Carcinoma Cell Metastasis and Enhances Apoptosis by Elevating miR-217

Background

Hepatocellular carcinoma (HCC) is a significant cause of human death in the world. Recently, it is found that midazolam can modulate miRs to participate in HCC progression. This research project was designed to elucidate the impacts of midazolam and miR-217 on HCC cell metastasis and apoptosis.

Methods

Human HCC cell strains (Hep3B and SK-HEP-1) were selected and intervened by midazolam at different concentrations in our research. miR-217-inhibitor intervened in the two HCC cell strains to observe the alterations of cell migration, invasiveness, and apoptosis. The miR-217 level in HCC cells was identified by reverse transcription-quantitative polymerase chain reaction (RT-qPCR).

Results

As midazolam concentration was elevated, Hep3B and SK-HEP-1 viabilities were more obviously suppressed. The 10 μg/mL concentration was selected for analysis since Hep3B and SK-HEP-1 had an IC50 of 10.57 μg/mL and 9.35 μg/m, respectively. The qRT-PCR results showed the decreased of miR-217 in HCC cells, which was enhanced notably by midazolam intervention. Compared with the blank group, the invasiveness and migration (Transwell assay) of miR-217-inhibitor-transfected HCC cells were distinctly enhanced and the apoptosis rate (flow cytometry) was noticeably reduced.

Conclusion

Midazolam can upregulate miR-217 in HCC cells, thus inhibiting HCC cell metastasis and apoptosis.

Non-coding RNAs in melanoma: Biological functions and potential clinical applications

Malignant melanoma (MM) is a malignant tumor that originates from melanocytes and has a high mortality rate. Therefore, early diagnosis and treatment are very important for survival. So far, the exact molecular mechanism leading to the occurrence of melanoma, especially the molecular metastatic mechanism, remains largely unknown. Non-coding RNAs (ncRNAs), such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNA (circRNAs), have been investigated and found to play vital roles in regulating tumor occurrence and development, including melanoma. In this review, we summarize the progress of recent research on the effects of ncRNAs on melanoma and attempt to elucidate the role of ncRNAs as molecular markers or potential targets that will provide promising application perspectives on melanoma.

Potential value of MicroRNA-21 as a biomarker for predicting the prognosis of patients with breast cancer: A protocol for meta-analysis and bioinformatics analysis

BACKGROUND

The latest global cancer data from 2020 shows that breast cancer has replaced lung cancer as the number one cancer in the world. Searching for new biomarkers of breast cancer has important clinical significance for early diagnosis, prediction of prognosis, and targeted therapy. MicroRNA-21 (miRNA-21) can be used as a new molecular marker for early diagnosis, prognosis, and treatment of tumors. However, the expression of miRNA-21 in breast cancer and its prognosis are not clear. Therefore, this study conducted a meta-analysis to further clarify the relationship between the expression of miRNA-21 in breast cancer and prognosis. At the same time, we carried out bioinformatics analysis to further analyze the possible molecular mechanism of miRNA-21, so as to provide potential clinical indicators for the diagnosis, treatment, and prognosis of patients.

METHODS

PubMed, Medline, Embase, Web of Science, Wanfang, Chinese Biomedical Literature Database, Chinese National Knowledge Infrastructure, and other databases were used to retrieve the published relevant literatures. Include the eligible research, extract the survival data hazard ratios and 95% confidence intervals and other information. STATA16.0 software was used for meta-analysis. Download the miRNA data of breast cancer through the Cancer Genome Atlas (TCGA) database and Gene Expression Omnibus (GEO) database. The data extracted for independent sample t test and ROC curve was drawn. OncomiR plotted the survival curve of miRNA-21 on the prognosis of breast cancer. The target genes of miRNA-21 were predicted, and the Gene Ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway were analyzed. STRING database and Cytoscape construct protein-protein interaction (PPI) network to obtain Hub gene. The correlation between the expression level of Hub gene in breast cancer and the abundance of immune cell infiltration was analyzed by TIMER database and verified by Kaplan-Meien plotter database.

RESULTS

The results of this meta-analysis will be submitted to a peer-reviewed journal for publication.

CONCLUSION

In this study, meta-analysis and bioinformatics analysis were used to further explore the prognosis, mechanism, and related pathways of miRNA-21 in breast cancer.

ETHICS AND DISSEMINATION

The private information from individuals will not be published. This systematic review also should not damage participants' rights. Ethical approval is not available. The results may be published in a peer-reviewed journal or disseminated in relevant conferences.

OSF REGISTRATION NUMBER

DOI 10.17605/OSF.IO/R32A9.

Knockdown of circ-UQCRC2 ameliorated lipopolysaccharide-induced injury in MRC-5 cells by the miR-326/PDCD4/NF-κB pathway

BACKGROUND

Circular RNAs (circRNAs) have been shown as important modulators in the pathogenesis of pediatric pneumonia. In this paper, we focused on the molecular basis of circRNA ubiquinol-cytochrome c reductase core protein 2 (circ-UQCRC2, circ_0038467) in lipopolysaccharide (LPS)-induced cell injury.

METHODS

Quantitative real-time polymerase chain reaction (qRT-PCR) was used to gauge the levels of circ-UQCRC2, microRNA (miR)-326 and programmed cell death 4 (PDCD4) mRNA. PDCD4 protein expression and the activation of the NF-κB signaling pathway were evaluated by western blot. Ribonuclease R (RNase R) assay was performed to assess the stability of circ-UQCRC2. Cell viability and apoptosis were detected by the Cell Counting Kit-8 (CCK-8) and flow cytometry assays, respectively. The levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and IL-6 were measured by the enzyme-linked immunosorbent assay (ELISA). Targeted relationship between miR-326 and circ-UQCRC2 or PDCD4 was confirmed by dual-luciferase reporter and RNA immunoprecipitation (RIP) assays.

RESULTS

Our data showed the up-regulation of circ-UQCRC2 level in pneumonia serum and LPS-treated MRC-5 cells. The silencing of circ-UQCRC2 attenuated LPS-induced MRC-5 cell injury. Mechanistically, circ-UQCRC2 directly targeted miR-326, and circ-UQCRC2 regulated PDCD4 expression through miR-326. MiR-326 was a downstream effector of circ-UQCRC2 function, and PDCD4 was a functional target of miR-326 in regulating LPS-induced MRC-5 cell injury. Additionally, circ-UQCRC2 knockdown inactivated the NF-κB signaling pathway by regulating the miR-326/PDCD4 axis.

CONCLUSION

Our findings demonstrated a novel regulatory network, the miR-326/PDCD4/NF-κB pathway, for the function of circ-UQCRC2 in LPS-induced cell injury in MRC-5 cells.

MicroRNA Signature in Melanoma: Biomarkers and Therapeutic Targets

Melanoma is the utmost fatal kind of skin neoplasms. Molecular changes occurring during the pathogenic processes of initiation and progression of melanoma are diverse and include activating mutations in BRAF and NRAS genes, hyper-activation of PI3K/AKT pathway, inactivation of p53 and alterations in CDK4/CDKN2A axis. Moreover, several miRNAs have been identified to be implicated in the biology of melanoma through modulation of expression of genes being involved in these pathways. In the current review, we provide a summary of the bulk of information about the role of miRNAs in the pathobiology of melanoma, their possible application as biomarkers and their emerging role as therapeutic targets for this kind of skin cancer.

Curcumin protects against inflammation and lung injury in rats with acute pulmonary embolism with the involvement of microRNA-21/PTEN/NF-κB axis

This study was intended to investigate the effect of Curcumin on acute pulmonary embolism (APE) via microRNA-21 (miR-21)/PTEN/NF-κB axis. APE model was induced on rats and administrated with Curcumin. Western blot analysis and RT-qPCR manifested the downregulation of Sp1, miR-21 and NF-κB, but the upregulation of PTEN in Curcumin-treated APE rats. Blood gas analysis, ELISA, and weighing of wet weight/dry weight (W/D) ratio indicated that Curcumin diminished mPAP and RVSP levels, W/D ratio, thrombus volume, and inflammatory factors in the lungs of APE rats. Further mechanical analysis was conducted by dual-luciferase reporter assays and ChIP assay, which showed that Sp1 increased miR-21 expression by binding to the miR-21 promoter, and that PTEN was targeted by miR-21. The APE rats were injected with adenovirus to evaluate the effect of Sp1, miR-21, or PTEN on lung injury and inflammation. It was observed that downregulation of miR-21 or Sp1, or upregulation of PTEN diminished mPAP and RVSP levels, W/D ratio, thrombus volume, and inflammatory factors in the lungs of APE rats. In summary, Curcumin decreased miR-21 expression by downregulating Sp1 to upregulate PTEN and to impair the NF-κB signaling pathway, thus suppressing lung injury and inflammation in APE rats.

MicroRNA-31 Can Positively Regulate the Proliferation, Differentiation and Migration of Keratinocytes

In the past decades, the key roles of most microRNA in dermatosis and skin development have been explored one after another. Among them, microRNA-31 (miR-31) has a prominent role in the regulation of keratinocytes. Numerous studies show that miR-31 can positively regulate the proliferation, differentiation and cell activity of keratinocytes via regulating the NF-κB, RAS/MAPK, Notch signaling pathways, and some cytokines. At present, the interaction between miR-31 and the NF-κB signaling pathway in keratinocytes is a hot research topic. The positive feedback loop formed by miR-31 and NF-κB signaling may bring new ideas for the prevention of psoriasis. The abnormal state of keratinocytes is usually the pathological basis of many skin and immune system diseases. Therefore, strengthening the ability to regulate keratinocytes may be a breakthrough for a variety of diseases. At the same time, miR-31's capacity to accelerate wound healing via positively regulating keratinocytes should be further investigated in the treatment of chronic ulcers and trauma.

MicroRNA-21 maintains hematopoietic stem cell homeostasis through sustaining the NF-κB signaling pathway in mice

Long-term hematopoietic output is dependent on hematopoietic stem cell (HSC) homeostasis which is maintained by a complex molecular network in which microRNA play crucial roles, although the underlying molecular basis has not been fully elucidated. Here we show that microRNA-21 (miR-21) is enriched in murine HSC, and that mice with conditional knockout of miR-21 exhibit an obvious perturbation in hematopoiesis. Moreover, significant loss of HSC quiescence and long-term reconstituting ability are observed in the absence of miR-21. Further studies revealed that miR-21 deficiency markedly decreases the nuclear factor kappa B (NF-B) pathway, accompanied by increased expression of PDCD4, a direct target of miR-21, in HSC. Interestingly, overexpression of PDCD4 in wild-type HSC generates similar phenotypes as those of miR-21-deficient HSC. More importantly, knockdown of PDCD4 can significantly rescue the attenuation of NF-B activity, thereby improving the defects in miR-21-null HSC. On the other hand, we found that miR-21 is capable of preventing HSC from ionizing radiation- induced DNA damage via activation of the NF-B pathway. Collectively, our data demonstrate that miR-21 is involved in maintaining HSC homeostasis and function, at least in part, by regulating the PDCD4-mediated NF-B pathway and provide a new insight into radioprotection of HSC.

Exosomal miR-21 secreted by IL-1β-primed-mesenchymal stem cells induces macrophage M2 polarization and ameliorates sepsis

Sepsis occurs due to a damaging host response to infection and is the chief cause of death in most intensive care units. Mesenchymal stem cells (MSCs) exhibit immunomodulatory properties and can modulate key cells of the innate and adaptive immune systems through various effector mechanisms, such as exosomes. Exosomes and their microRNA (miRNA or miR) cargo including miR-21 can initiate profound phenotypic changes in the tumor microenvironment due to their intercellular communication transmitting the pleiotropic messages between different cell types, tissues, and body fluids. Here, we aimed to characterize the effect of miR-21 delivered from MSC-derived exosomes on the polarization of macrophages in a mouse sepsis model. First, we isolated exosomes from interleukin-1β (IL-1β)-pretreated murine MSCs (βMSCs) and injected them into cecal ligation and puncture (CLP) septic models. We found that βMSCs-derived exosomes could more effectively induce M2-like polarization of macrophages in vitro and in vivo. Administration of βMSCs-derived exosomes attenuated the symptoms in septic mice more effectively and increased their survival rate as compared to exosomes released by naïve MSCs. Importantly, we found that miR-21 was abundantly upregulated in MSCs upon IL-1β stimulation and packaged into exosomes. This exosomal miR-21 was transferred to macrophages, leading to M2 polarization in vitro and in vivo. The therapeutic efficacy of βMSC-derived exosomes was partially lost upon miR-21 inhibition by its specific inhibitors. More specifically, we demonstrated βMSCs-derived exosomes inhibited the effects of PDCD4, the target gene of miR-21, on macrophage polarization and sepsis. In conclusion, exosomal miR-21 emerged as a key mediator of IL-1β pretreatment induced immunomodulatory properties of MSCs. The study indicated a novel basis for therapeutic application of MSCs in sepsis.

Human umbilical cord mesenchymal stem cells-derived exosomal microRNA-451a represses epithelial-mesenchymal transition of hepatocellular carcinoma cells by inhibiting ADAM10

Exosomes derived from human umbilical cord mesenchymal stem cells (hucMSCs) expressing microRNAs (miRNAs) have been highlighted in human cancers. However, the detailed molecular mechanism of hucMSCs-derived exosomal miR-451a on hepatocellular carcinoma (HCC) remains further investigation. Our study aims to explore the impact of exosomal miR-451a on the progression of HCC. Expression of miR-451a and a disintegrin and metalloprotease 10 (ADAM10) in HCC tissues and adjacent normal tissues were determined. The exosomes were extracted from hucMSCs and co-cultured with Hep3B and SMMC-7721 cell lines. After the treatment of relative exosomes or exosome inhibitor GW4869 in Hep3B and SMMC-7721 cells, the paclitaxel resistance and malignant phenotypes of HCC cells were measured. Moreover, the effect of hucMSCs-derived exosomes on the expression of miR-451a and ADAM10 in HCC cells was assessed. The targeting relationship between miR-451a and ADAM10 was verified to detect the impact of ADAM10-wild type and ADAM10-mutant type (MUT) on HCC cell processes. Low expression of miR-451a and high expression of ADAM10 indicated a poor prognosis of HCC patients. MiR-451a was up-regulated while ADAM10 was down-regulated in HCC cells after co-culture with HucMSC-derived exosomes. The exosomes elevated miR-451a and inhibited ADAM10 to suppress the paclitaxel resistance, cell cycle transition, proliferation, migration and invasion, and promote apoptosis of HCC cells. ADAM10 was verified to be a target gene of miR-451a. ADAM10-MUT promoted HCC process independent of miR-451a mimic. HucMSC-derived exosomal miR-451a could restrict the epithelial-mesenchymal transition of HCC cells by targeting ADAM10, which might provide new targets for HCC treatment.

Importance of microRNAs in Skin Oncogenesis and Their Suitability as Agents and Targets for Topical Therapy

Skin cancer is the most common cancer worldwide, with rapidly increasing incidence and consistent mortality. Skin cancer encompasses melanoma and non-melanoma skin cancer, which in turn is mainly divided into cutaneous squamous cell carcinoma and basal cell carcinoma. Small noncoding micro-RNAs (miRNAs) regulate protein expression after transcription and play a role in the development and progression of skin cancer. Deregulated expression of miRNAs in skin cancer is associated with cell proliferation, angiogenesis, metastasis, apoptosis, immune response, and drug resistance. Specific patterns of miRNAs in specific skin cancer types can be used as diagnostic markers. For therapeutic purposes, both miRNA and chemically modified variants thereof as well as miRNA antagonists (antagomiRs) or RNA inhibitors may be applied topically. Due to their specific physicochemical properties, physical or chemical diffusion promoters are used with varying degrees of success. There is no question by now that such preparations have a high potential for the treatment of epithelial skin tumors in particular.

Reconstruction of lncRNA-miRNA-mRNA network based on competitive endogenous RNA reveals functional lncRNAs in skin cutaneous melanoma

BACKGROUND

Human skin cutaneous melanoma is the most common and dangerous skin tumour, but its pathogenesis is still unclear. Although some progress has been made in genetic research, no molecular indicators related to the treatment and prognosis of melanoma have been found. In various diseases, dysregulation of lncRNA is common, but its role has not been fully elucidated. In recent years, the birth of the "competitive endogenous RNA" theory has promoted our understanding of lncRNAs.

METHODS

To identify the key lncRNAs in melanoma, we reconstructed a global triple network based on the "competitive endogenous RNA" theory. Gene Ontology and KEGG pathway analysis were performed using DAVID (Database for Annotation, Visualization, and Integration Discovery). Our findings were validated through qRT-PCR assays. Moreover, to determine whether the identified hub gene signature is capable of predicting the survival of cutaneous melanoma patients, a multivariate Cox regression model was performed.

RESULTS

According to the "competitive endogenous RNA" theory, 898 differentially expressed mRNAs, 53 differentially expressed lncRNAs and 16 differentially expressed miRNAs were selected to reconstruct the competitive endogenous RNA network. MALAT1, LINC00943, and LINC00261 were selected as hub genes and are responsible for the tumorigenesis and prognosis of cutaneous melanoma.

CONCLUSIONS

MALAT1, LINC00943, and LINC00261 may be closely related to tumorigenesis in cutaneous melanoma. In addition, MALAT1 and LINC00943 may be independent risk factors for the prognosis of patients with this condition and might become predictive molecules for the long-term treatment of melanoma and potential therapeutic targets.

Hypoxia alleviates dexamethasone-induced inhibition of angiogenesis in cocultures of HUVECs and rBMSCs via HIF-1α

BACKGROUND AND AIM

Inadequate vascularization is a challenge in bone tissue engineering because internal cells are prone to necrosis due to a lack of nutrient supply. Rat bone marrow-derived mesenchymal stem cells (rBMSCs) and human umbilical vein endothelial cells (HUVECs) were cocultured to construct prevascularized bone tissue in osteogenic induction medium (OIM) in vitro. The angiogenic capacity of HUVECs was limited in the coculture system. In this study, the effects of the components in the medium on HUVEC angiogenesis were analyzed.

METHODS

The coculture system was established in OIM. Alizarin red staining and alkaline phosphatase staining were used to assess the osteogenic ability of MSCs. A Matrigel tube assay was used to assess the angiogenic ability of HUVECs in vitro. The proliferation of HUVECs was evaluated by cell counting and CCK-8 assays, and migration was evaluated by the streaked plate assay. The expression levels of angiogenesis-associated genes and proteins in HUVECs were measured by qRT-PCR and Western blotting, respectively.

RESULTS

Dexamethasone in the OIM suppressed the proliferation and migration of HUVECs, inhibiting the formation of capillary-like structures. Our research showed that dexamethasone stimulated HUVECs to secrete tissue inhibitor of metalloproteinase (TIMP-3), which competed with vascular endothelial growth factor (VEGF-A) to bind to vascular endothelial growth factor receptor 2 (VEGFR2, KDR). This effect was related to inhibiting the phosphorylation of ERK and AKT, which are two downstream targets of KDR. However, under hypoxia, the enhanced expression of hypoxia-inducible factor-1α (HIF-1α) decreased the expression of TIMP-3 and promoted the phosphorylation of KDR, improving HUVEC angiogenesis in the coculture system.

CONCLUSION

Coculture of hypoxia-preconditioned HUVECs and MSCs showed robust angiogenesis and osteogenesis in OIM, which has important implications for prevascularization in bone tissue engineering in the future.

MicroRNA-21-Enriched Exosomes as Epigenetic Regulators in Melanomagenesis and Melanoma Progression: The Impact of Western Lifestyle Factors

DNA mutation-induced activation of RAS-BRAF-MEK-ERK signaling associated with intermittent or chronic ultraviolet (UV) irradiation cannot exclusively explain the excessive increase of malignant melanoma (MM) incidence since the 1950s. Malignant conversion of a melanocyte to an MM cell and metastatic MM is associated with a steady increase in microRNA-21 (miR-21). At the epigenetic level, miR-21 inhibits key tumor suppressors of the RAS-BRAF signaling pathway enhancing proliferation and MM progression. Increased MM cell levels of miR-21 either result from endogenous upregulation of melanocytic miR-21 expression or by uptake of miR-21-enriched exogenous exosomes. Based on epidemiological data and translational evidence, this review provides deeper insights into environmentally and metabolically induced exosomal miR-21 trafficking beyond UV-irradiation in melanomagenesis and MM progression. Sources of miR-21-enriched exosomes include UV-irradiated keratinocytes, adipocyte-derived exosomes in obesity, airway epithelium-derived exosomes generated by smoking and pollution, diet-related exosomes and inflammation-induced exosomes, which may synergistically increase the exosomal miR-21 burden of the melanocyte, the transformed MM cell and its tumor environment. Several therapeutic agents that suppress MM cell growth and proliferation attenuate miR-21 expression. These include miR-21 antagonists, metformin, kinase inhibitors, beta-blockers, vitamin D, and plant-derived bioactive compounds, which may represent new options for the prevention and treatment of MM.

RKIP Regulates Differentiation-Related Features in Melanocytic Cells

Raf Kinase Inhibitor Protein (RKIP) has been extensively reported as an inhibitor of key signaling pathways involved in the aggressive tumor phenotype and shows decreased expression in several types of cancers. However, little is known about RKIP in melanoma or regarding its function in normal cells. We examined the role of RKIP in both primary melanocytes and malignant melanoma cells and evaluated its diagnostic and prognostic value. IHC analysis revealed a significantly higher expression of RKIP in nevi compared with early-stage (stage I–II, AJCC 8th) melanoma biopsies. Proliferation, wound healing, and collagen-coated transwell assays uncovered the implication of RKIP on the motility but not on the proliferative capacity of melanoma cells as RKIP protein levels were inversely correlated with the migration capacity of both primary and metastatic melanoma cells but did not alter other parameters. As shown by RNA sequencing, endogenous RKIP knockdown in primary melanocytes triggered the deregulation of cellular differentiation-related processes, including genes (i.e., ZEB1, THY-1) closely related to the EMT. Interestingly, NANOG was identified as a putative transcriptional regulator of many of the deregulated genes, and RKIP was able to decrease the activation of the NANOG promoter. As a whole, our data support the utility of RKIP as a diagnostic marker for early-stage melanomas. In addition, these findings indicate its participation in the maintenance of a differentiated state of melanocytic cells by modulating genes intimately linked to the cellular motility and explain the progressive decrease of RKIP often described in tumors.

Extracellular vesicle miRNA-21 is a potential biomarker for predicting chronic lung disease in premature infants

Premature infants are often exposed to positive pressure ventilation and supplemental oxygen, which leads to the development of chronic lung disease (CLD). There are currently no standard serum biomarkers used for prediction or early detection of patients who go on to develop CLD. MicroRNAs (miRNAs) are a novel class of naturally occurring, short, noncoding substances that regulate gene expression at the posttranscriptional level and cause translational inhibition and/or mRNA degradation and present in body fluids packaged in extracellular vesicles (EVs), rendering them remarkably stable. Our aim was to evaluate miRNAs identified in serum EVs of premature infants as potential biomarkers for CLD. Serum EVs were extracted from premature infants at birth and on the 28th day of life (DOL). Using a human miRNA array, we identified 62 miRNAs that were universally expressed in CLD patients and non-CLD patients. Of the 62 miRNAs, 59 miRNAs and 44 miRNAs were differentially expressed on DOL0 and DOL28 in CLD and non-CLD patients, respectively. Of these miRNAs, serum EV miR-21 was upregulated in CLD patients on DOL28 compared with levels at birth and downregulated in non-CLD patients on DOL28 compared with levels at birth. In neonatal mice exposed to hyperoxia for 7days, as a model of CLD, five miRNAs (miR-34a, miR-21, miR-712, miR-682, and miR-221) were upregulated, and 7 miRNAs (miR-542-5p, miR-449a, miR-322, miR-190b, miR-153, miR-335-3p, miR-377) were downregulated. MiR-21 was detected as a common miRNA that changed in CLD patients and in the hyperoxia exposed mice. We conclude that EV miR-21 may be a biomarker of CLD.

Uncoupling protein 2 is upregulated in melanoma cells and contributes to the activation of Akt/mTOR and ERK signaling

The aim of the present study was to characterize the expression of uncoupling protein 2 (UCP2) in melanoma and to study the potential mechanisms underlying the involvement of UCP2 in melanomagenesis using human melanoma cell lines. The expression of UCP2 was evaluated in specimens from normal control subjects, patients with compound nevus, and patients with cutaneous and mucosal melanoma. Stable knockdown of UCP2 was achieved in human melanoma cell lines, which were used to examine whether UCP2 knockdown affects the mitochondrial membrane potential and intracellular levels of ATP, reactive oxygen species and lactate. Cell proliferation, invasion, spheroid formation and cisplatin sensitivity were also evaluated in the UCP2 knockdown cells. Finally, the effects of UCP2 knockdown on the Akt/mammalian target of rapamycin (mTOR) and extracellular signal‑regulated kinase (ERK) pathways, which are important oncogenic pathways during melanomagenesis, were evaluated. Relatively high expression of UCP2 was detected in human melanoma specimens, which was correlated with Clark level and Breslow thickness. Knockdown of UCP2 suppressed cell proliferation, invasion and spheroid formation, and increased the sensitivity of melanoma cells to cisplatin. Furthermore, the UCP2 knockdown cells exhibited inhibition of Akt/mTOR signaling and ERK activation. Therefore, human melanoma tissues exhibit relatively high UCP2 expression, which may be implicated in the mechanisms underlying tumor progression. The potential role of UCP2 in melanomagenesis may involve enhancing the Akt/mTOR and mitogen‑activated protein kinase/ERK pathways.

miRNAs as Key Players in the Management of Cutaneous Melanoma

The number of treatment options for melanoma patients has grown in the past few years, leading to considerable improvements in both overall and progression-free survival. Targeted therapies and immune checkpoint inhibitors have opened a new era in the management of melanoma patients. Despite the clinical advances, further research efforts are needed to identify other "druggable" targets and new biomarkers to improve the stratification of melanoma patients who could really benefit from targeted and immunotherapies. To this end, many studies have focused on the role of microRNAs (miRNAs) that are small non-coding RNAs (18-25 nucleotides in length), which post-transcriptionally regulate the expression of their targets. In cancer, they can behave either as oncogenes or oncosuppressive genes and play a central role in many intracellular pathways involved in proliferation and invasion. Given their modulating activity on the transcriptional landscape, their biological role is under investigation to study resistance mechanisms. They are able to mediate the communication between tumor cells and their microenvironment and regulate tumor immunity through direct regulation of the genes involved in immune activation or suppression. To date, a very promising miRNA-based strategy is to use them as prognosis and diagnosis biomarkers both as cell-free miRNAs and extracellular-vesicle miRNAs. However, miRNAs have a complex role since they target different genes in different cellular conditions. Thus, the ultimate aim of studies has been to recapitulate their role in melanoma in biological networks that account for miRNA/gene expression and mutational state. In this review, we will provide an overview of current scientific knowledge regarding the oncogenic or oncosuppressive role of miRNAs in melanoma and their use as biomarkers, with respect to approved therapies for melanoma treatment.

Curcumol inhibits the proliferation and metastasis of melanoma via the miR-152-3p/PI3K/AKT and ERK/NF-κB signaling pathways

Melanoma is the most aggressive and treatment-resistant form of skin cancer. Curcumol is a Chinese medicinal herb traditionally used as a cancer remedy. However, the molecular mechanisms underlying the anticancer activity of curcumol in melanoma remains largely unknown. In the present study, we observed that Curcumol decreased mouse melanoma B16 cell proliferation and migration. The xenograft tumor assay showed that curcumol reduced melanoma volume and lung metastasis. Curcumol upregulated the expression of E-cadherin and downregulated the expression of N-cadherin, MMP2 and MMP9 in mouse melanoma B16 cell. Western blot analysis revealed that curcumol reduced the translocation of p65 to the nucleus and decreased p-ERK. Furthermore, curcumol attenuated c-MET, P13K and p-AKT protein expression and upregulated miR-152-3p gene expression. The dual-luciferase reporter assay indicated that c-MET was a target gene of miR-152-3p. Reduced expression of miR-152-3p partially attenuated the effect of curcumol on mouse melanoma B16 cell proliferation and migration. The decrease in c-MET, P13K and p-AKT protein expression following curcumol treatment in mouse melanoma B16 cells was notably attenuated by the miR-152-3p inhibitor. Taken together, our findings suggested that curcumol attenuated melanoma progression and concomitantly suppressed ERK/NF-κB signaling and promoted miR-152-3p expression to inactivate the c-MET/PI3K/AKT signaling pathway.

Exosomal hsa-miR-21-5p derived from growth hormone-secreting pituitary adenoma promotes abnormal bone formation in acromegaly

Growth hormone-secreting pituitary adenoma (GHPA), a benign endocrine tumor located in the base of the skull, results in acromegaly. In addition to the mass effect of the tumor itself in the sellar region, GHPA can lead to the overgrowth of almost every organ. Previous findings indicated that the processes underlying acromegaly were partly attributable to hyperactivity of the growth hormone/insulin-like growth factor-1 (GH/IGF-1) axis. However, the mechanisms driving this syndrome remains largely unknown. Additionally, the roles of GHPA-derived exosomes, which contain functional microRNAs and proteins that manipulate target cell proliferation and differentiation in distal extremities, are also unknown. In this study, we demonstrated that GHPA exosomes promote bone formation in vitro and trabecula number in vivo. The mechanism of increased trabecula formation may be attributable to GHPA exosome-induced osteoblast proliferation via increased cell viability and DNA replication. We further discovered that exosomal hsa-miR-21-5p plays a distinct role from the GH/IGF-1 axis in these processes. Accordingly, the results of this study provide a novel mechanism whereby GHPA influences distal extremities and a new perspective for treating GHPA.

RETRACTED: The protective role of microRNA-133b in restricting hippocampal neurons apoptosis and inflammatory injury in rats with depression by suppressing CTGF

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. Concern was raised about the integrity of the images in Figures 5, 6A and 8A, which appear to contain suspected duplications, as detailed here: https://pubpeer.com/publications/773D824533241B2186D16AA3FFCB3F and here: https://docs.google.com/spreadsheets/d/1r0MyIYpagBc58BRF9c3luWNlCX8VUvUuPyYYXzxWvgY/edit#gid=262337249. Additional suspected image duplications were detected within Figure 7A. Our analysis suggested these image anomalies represent either direct duplications of the entire image, or contain several repeated features between or within an image. The journal requested the corresponding author comment on these concerns and provide the raw data. The authors did not respond to this request and therefore the Editor-in-Chief decided to retract the article.

Circulating microRNAs as biomarkers for early diagnosis of cutaneous melanoma

Introduction: Cutaneous melanoma is the deadliest form of skin cancer, with a dramatic increase in the incidence rate worldwide over the past decade. Early detection has been shown to improve the outcome of melanoma patients. The identification of noninvasive biomarkers able to identify melanoma at an early stage remains an unmet clinical need. Circulating miRNAs (c-miRNAs), small non-coding RNAs, appear as potential ideal candidate biomarkers due to their stability in biological fluids and easy detectability. Moreover, c-miRNAs are reported to be heavily deregulated in cancer patients.Areas covered: This review examines evidence of the specific c-miRNAs or panels of c-miRNAs reported to be useful in discriminating melanoma from benign cutaneous lesions.Expert opinion: Although the interesting reported by published studies, the non-homogeneity of detection and normalization methods prevents the individuation of single c-miRNA or panel of c-miRNAs that are specific for early detection of cutaneous melanoma. In the future, prospective wide and well-designed clinical trials will be needed to validate the diagnostic potential of some of the c-miRNA candidates in clinical practice.

Midazolam inhibits proliferation and accelerates apoptosis of hepatocellular carcinoma cells by elevating microRNA-124-3p and suppressing PIM-1

OBJECTIVE

Recently, the impact of microRNAs (miRNAs) has been identified in hepatocellular carcinoma (HCC), this study was designed to assess the effects of miR-124-3p and midazolam (MDZ) in HCC with the involvement of PIM-1.

METHODS

HepG₂ human HCC cells were selected for our study, which were treated with different concentrations of MDZ. The gain- and loss-of-function experiments were performed to elucidate the migration, invasion, proliferation, colony formation ability, cell cycle, and apoptosis of HepG₂ cells upon treatment of MDZ, miR-124-3p mimics, or miR-124-3p inhibitor. The expression levels of miR-124-3p, PIM-1, Bax, Bcl-2, P21, and Ki-67 in HepG₂ cells were assessed by reverse transcription quantitative polymerase chain reaction and western blot analysis. Moreover, HepG₂ cell growth in vivo was measured by subcutaneous tumorigenesis in nude mice, and the target relation between miR-124-3p and PIM-1 was evaluated using dual luciferase reporter gene assay.

RESULTS

We have found that after treated with overexpression of miR-124-3p and MDZ, there exhibited elevated miR-124-3p, declined expression of PIM-1, attenuated migration, invasion, proliferation and colony formation ability, and promoted apoptosis of HepG₂ cells. Additionally, it could be observed that the tumor volume and weight were all reduced upon treatment of overexpression of miR-124-3p and MDZ. Meanwhile, the results in the HepG₂ cells that treated with down-regulated miR-124-3p were the opposite. Furthermore, PIM-1 was found to be a target gene of miR-124-3p.

CONCLUSION

Our study found that MDZ could inhibit proliferation and accelerate apoptosis of HCC cells by elevation of miR-124-3p and suppressing PIM-1, which may be an effective method in the treatment of HCC.

MicroRNA-21 deficiency attenuated atherogenesis and decreased macrophage infiltration by targeting Dusp-8

BACKGROUND AND AIMS

Atherosclerosis is a chronic inflammatory disorder mediated by macrophage activation. MicroRNA-21 (miR-21) is a key regulator in the macrophage inflammatory response. However, the functional role of miR-21 in atherogenesis is far from clear.

METHODS AND RESULTS

Here, we report that miR-21 is significantly upregulated in mouse atherosclerotic plaques and peripheral monocytes from patients with coronary artery disease. Compared with miR-21^+/+apoE^-/- mice (apoE^-/- mice), miR-21^-/-apoE^-/- (double knockout, DKO) mice showed less atherosclerotic lesions, reduced presence of macrophages, decreased smooth muscle cells(SMC) and collagen content in the aorta. We further explored the role of miR-21 in macrophage activation in vitro. Bone marrow-derived macrophages (BMDMs) from DKO mice not only exhibit impaired function of migration induced by chemokine (C-C motif) ligand 2 (CCL2) but also a weakened macrophage-endothelium interaction activated by tumor necrosis factor-α (TNF-α). However, atherogenic inflammatory cytokine secretion was not affected by miR-21 in vitro or in vivo. Additionally, miR-21 knockdown in BMDMs directly derepressed the expression of dual specificity protein phosphatase 8 (Dusp-8), a previously validated miR-21 target in cardiac fibroblasts, which negatively regulates mitogen-activated protein kinase (MAPK) signaling, particularly the p38-and c-Jun N-terminal kinase (JNK)-related signaling pathways.

CONCLUSIONS

These data demonstrate that inhibition of miR-21 may restrict the formation of atherosclerotic plaques partly by regulating macrophage migration and adhesion, while, reduced SMCs and collagen content in plaques may lead to a less stable phenotype with the progression of atherosclerosis. Thus, the absence of miR-21 reduces atherosclerotic lesions but may not represent all benefit in atherosclerosis development.

The "-OMICS" facet of melanoma: Heterogeneity of genomic, proteomic and metabolomic biomarkers

In the recent decade, cutting edge molecular and proteomic analysis platforms revolutionized biomarkers discovery in cancers. Melanoma is the prototype with over 51,100 biomarkers discovered and investigated thus far. These biomarkers include tissue based tumor cell and tumor microenvironment biomarkers and circulating biomarkers including tumor DNA (cf-DNA), mir-RNA, proteins and metabolites. These biomarkers provide invaluable information for diagnosis, prognosis and play an important role in prediction of treatment response. In this review, we summarize the most recent discoveries in each of these biomarker categories. We will discuss the challenges in their implementation and standardization and conclude with some perspectives in melanoma biomarker research.

Circulating cell-free microRNAs in cutaneous melanoma staging and recurrence or survival prognosis

Cutaneous melanoma is a skin cancer with increasing incidence. Identification of novel clinical biomarkers able to detect the stage of disease and suggest prognosis could improve treatment and outcome for melanoma patients. Cell-free microRNAs (cf-miRNAs) are the circulating copies of short non-coding RNAs involved in gene expression regulation. They are released into the interstitial fluid, are detectable in blood and other body fluids and have interesting features of ideal biomarker candidates. They are stable outside the cell, tissue specific, vary along with cancer development and are sensitive to change in the disease course such as progression or therapeutic response. Moreover, they are accessible by non-invasive methods or venipuncture. Some articles have reported different cf-miRNAs with the potential of diagnostic tools for melanoma staging, recurrence and survival prediction. Although some concordance of results is already emerging, differences in analytical methods, normalization strategies and tumour staging still will require further research and standardization prior to clinical usage of cf-miRNA analysis. This article reviews this literature with the aim of contributing to a shared focusing on these new promising tools for melanoma treatment and care.

Overexpression of microRNA‑21 inhibits the growth and metastasis of melanoma cells by targeting MKK3

Melanoma is an aggressive skin carcinoma with poor prognosis, and is prevalent worldwide. It was demonstrated that microRNA (miR)-21 and mitogen-activated protein kinase kinase 3 (MKK3) both participated in the occurrence and development of various tumors; however, their detailed roles in the progression of melanoma remain unclear. Reverse transcription-quantitative PCR (RT-qPCR) and western blot analyses were conducted to examine the expression levels of miR-21 and MKK3 in clinical specimens of patients with melanoma and melanoma cell lines. A dual-luciferase reporter assay was performed to verify the target interaction between miR-21 and MKK3. The mRNA and protein expressions of MKK3 were measured using RT-qPCR and western blot analysis, respectively, following transfection with miR-21 mimics and inhibitor. Subsequently, Cell Counting Kit-8 and colony formation assays, and flow cytometry were conducted to assess the effects of miR-21 and MKK3 on the cell growth of melanoma. Cell migration and invasion experiments were performed to evaluate the effects of miR-21 and MKK3 on the cell metastasis of melanoma. It was revealed that MKK3 was upregulated, and miR-21 was downregulated in patients with melanoma and melanoma cell lines. MKK3 was demonstrated to be a direct target of miR-21. Furthermore, it was demonstrated that upregulated miR-21 expression and downregulated MKK3 expression suppressed cell proliferation and colony formation, promoted apoptosis, delayed the cell cycle, and inhibited cell migration and invasion. The present findings suggested that miR-21 could inhibit the cell growth and metastasis of melanoma by negatively regulating MKK3.

MicroRNA heterogeneity in melanoma progression

The altered expression of miRNAs has been linked with neocarcinogenesis or the development of human malignancies including melanoma. Of significance, multiple clinical studies have documented that distinct sets of microRNAs (miRNAs) could be utilized as prognostic biomarkers for cancer development or predict the outcomes of treatment responses. To that end, an in-depth validation of such differentially expressed miRNAs is necessary in diverse settings of cancer patients in order to devise novel approaches to control tumor growth and/or enhance the efficacy of clinically-relevant therapeutic options. Moreover, considering the heterogeneity and sophisticated regulation of miRNAs, the precise delineation of their cellular targets could also be explored to design personalized medicine. Given the significance of miRNAs in regulating several key cellular processes of tumor cells including cell cycle progression and apoptosis, we review the findings of such miRNAs implicated in melanoma tumorigenesis. Understanding the novel mechanistic insights of such miRNAs will be useful for developing diagnostic or prognostic biomarkers or devising future therapeutic intervention for malignant melanoma.

Programmed cell death factor 4 enhances the chemosensitivity of colorectal cancer cells to Taxol

Drug resistance and disease relapse are still challenging problems in the chemotherapy of colorectal cancer (CRC). Programmed cell death factor 4 (PDCD4) has previously been reported to act as a tumor suppressor and was implicated in the chemosensitivity of numerous types of human malignancy. In this study, the effect of PDCD4 in the sensitivity of CRC to the chemotherapy drug Taxol was investigated. The results confirmed that lower PDCD4 expression was present in CRC tumor tissues, when compared with in normal adjacent tissues (p) and closely associated with the prognosis of patients with CRC. Upregulation of PDCD4 significantly enhanced the sensitivity of CRC cells to Taxol, by partially contributing to pro-apoptosis and anti-invasion pathways, both through upregulation of the apoptosis-associated protein Bax, and downregulation of the anti-apoptosis protein Bcl-2 and invasion-associated proteins MMP-9. These findings might present a novel strategy for sensitizing tumor cells to apoptosis and, thus, overcoming chemotherapy resistance in CRC.

Long Noncoding RNA MRPL39 Inhibits Gastric Cancer Proliferation and Progression by Directly Targeting miR-130

BACKGROUND

Gastric cancer (GC) is one of the most prevalent malignant tumors displaying both high incidence and mortality throughout much of the world. Recently, long noncoding RNAs (lncRNAs) have been implicated in the development and progression of GC.

MATERIALS AND METHODS

In the present study, we investigated the biological function and molecular mechanisms of lncRNA MRPL39 in GC.

RESULTS

We found that MRPL39 was significantly downregulated in GC tissues and cell lines and that its expression level was negatively associated with carcinoma size, tumor, lymph node, metastasis (TNM) stage, and lymphatic metastasis. Patients with low MRPL39 expression levels revealed a short overall and disease-free survival period. Over-expression of MRPL39 in the GC cell lines BGC823 and SGC-7901 inhibited cell growth, proliferation, migration, and invasion. MiR-130, a putative target gene of MRPL39, displayed an inverse association with the expression of MRPL39 in GC tissues and cell lines. Moreover, a luciferase assay demonstrated a direct binding between the miR-130 and MRPL39, and the reintroduction of miR-130 abrogated the anti-tumor effect of MRPL39 on GC cells.

CONCLUSION

Taken together, these findings indicate that MRPL39 serves as a tumor suppressor by directly targeting miR-130 in GC, which suggests that it might be a novel biomarker in the diagnosis and prognosis of GC.

miR-885-5p suppresses osteosarcoma proliferation, migration and invasion through regulation of β-catenin

MicroRNAs (miRs) have been reported to serve key roles in cancer. To investigate the function of miR-885-5p in osteosarcoma, the expression levels of miR-885-5p were analyzed in 85 osteosarcoma tissue samples and adjacent non-cancerous tissue samples, using reverse transcription-quantitative polymerase chain reaction analysis. It was demonstrated that miR-885-5p was downregulated in osteosarcoma tissues and cell lines. Notably, the expression level of miR-885-5p was closely associated with tumor size, Tumor-Node-Metastasis stage and lymph node metastasis. Additionally, low expression levels of miR-885-5p also predicted a poor prognosis of osteosarcoma. To further decipher the roles of miR-885-5p in osteosarcoma, it was determined that β-catenin, a key component of the Wnt signaling pathway, was a target of miR-885-5p. Furthermore, several functional experiments, including a colony formation assay, CCK-8 assay, wound healing assay and Transwell invasion assay, revealed that miR-885-5p suppressed cell proliferation, migration and invasion through inhibition of β-catenin. The results of the present study provide a novel insight into the molecular roles of miR-885-5p in osteosarcoma.

Cyanidin-3-glucoside attenuates the angiogenesis of breast cancer via inhibiting STAT3/VEGF pathway

Angiogenesis plays a pivotal role in breast cancer progression. Cyanidin-3-glucoside (C3G), one of the most widely distributed anthocyanins in edible fruits, shows antioxidative and anti-inflammatory property as well as induction of breast cancer cells apoptosis. However, the effect of C3G on breast cancer-induced angiogenesis remains unknown. In the present study, we found that C3G could attenuate breast cancer-induced angiogenesis via inhibiting VEGF, a key cytokine for angiogenesis, expression and secretion. Furthermore, signal transducer and activator of transcription 3 (STAT3) could transcriptionally activate VEGF, and C3G reduced STAT3 expression at both mRNA and protein level. Subsequently, our data showed that C3G induced miR-124 expression. Moreover, miR-124 could directly repress STAT3 expression, and miR-124-mediated STAT3 down-regulation was responsible for the inhibition of C3G on VEGF and angiogenesis. Taken together, we supplied more evidence to the anti-breast cancer property of C3G.

Cantharidin inhibits melanoma cell proliferation via the miR‑21‑mediated PTEN pathway

Cantharidin (CTD) is an active component isolated from the blister beetle that has been demonstrated to exert antitumor effects on multiple types of cancer. The current study aimed to investigate whether the potential inhibitory effects of CTD exist in human melanoma cells and to assess the underlying antitumor mechanisms of CTD. Using the Cell Counting Kit‑8 assay, it was demonstrated that CTD treatment reduced A375 cell proliferation significantly in a dose‑dependent manner. The colony formation assay demonstrated that CTD treatment could decrease the number of A375 cell colonies. Using subcutaneous xenograft tumor models, it was also demonstrated that CTD retarded solid tumor growth significantly. Furthermore, CTD treatment could induce A375 cell apoptosis, as detected by Annexin V‑fluorescein isothiocyanate/propidium iodide staining and western blot analysis. Notably, CTD treatment reduced microRNA (miR)‑21 expression and enhanced phosphatase and tensin homolog (PTEN) protein expression levels in A375 cells. Furthermore, overexpressing miR‑21 in A375 cells with the miR‑21 agomir blocked the antitumor effect of CTD both in vitro and in vivo. Finally, it was demonstrated that the inhibitory effects of CTD on A375 cells may be regulated by attenuating miR‑21‑mediated PTEN suppression. Based on these observations, it was suggested that CTD be used as a novel anti‑proliferation agent of human melanoma via targeting the miR‑21‑PTEN signaling pathway.

Isoalantolactone Inhibits Esophageal Squamous Cell Carcinoma Growth Through Downregulation of MicroRNA-21 and Derepression of PDCD4

BACKGROUND

This study was designed to explore the anticancer potential of isoalantolactone, a sesquiterpene lactone, on esophageal squamous cell carcinoma (ESCC) cells and associated molecular mechanisms.

METHODS

ESCC cell lines were treated with isoalantolactone or vehicle and tested for viability, proliferation, cell cycle distribution, and apoptosis. Xenograft tumor studies in nude mice were done to examine the in vivo anticancer effect of isoalantolactone.

RESULTS

Isoalantolactone treatment reduced ESCC cell viability and proliferation in vitro, which was coupled with induction of G0/G1 cell cycle arrest and apoptosis. In vivo studies confirmed the growth-suppressive effect of isoalantolactone on ESCC cells. Mechanistically, isoalantolactone reversed microRNA-21-mediated repression of programmed cell death 4 (PDCD4). Overexpression of microRNA-21 and knockdown of PDCD4 blocked the growth suppression and apoptosis induction by isoalantolactone in ESCC cells.

CONCLUSIONS

Isoalantolactone shows growth-suppressive activity against ESCC cells, which is ascribed to upregulation of PDCD4 via downregulation of microRNA-21.

Long non-coding RNA CASC15 promotes melanoma progression by epigenetically regulating PDCD4

Background

Long non-coding RNAs (LncRNAs) have been identified as critical regulators in a variety of cancer types. Cancer susceptibility candidate 15 (CASC15), a lncRNA located at chromosome 6p22.3, has been discovered to participate in melanoma progression and phenotype switching. Nevertheless, the roles and molecular mechanisms of CASC15 in melanoma are far from being understood.

Results

We found that CASC15 expression was up-regulated in melanoma tissues and associated with advanced pathological stages. Function experiments displayed that CASC15 knockdown hindered proliferation, facilitated apoptosis and suppressed invasion, while CASC15 overexpression facilitated proliferation and invasion in melanoma cells. Further mechanistic analysis showed that CASC15 epigenetically silenced the expression of programmed cell death 4 (PDCD4) by recruiting EZH2 and increasing H3K27me3 level at the promoter region of PDCD4. Additionally, PDCD4 overexpression inhibited proliferation, enhanced apoptosis and decreased invasion of melanoma cells. Moreover, CASC15-knockdown-induced anti-cancer effects were abated by PDCD4 down-regulation. Furthermore, depletion of CASC15 blocked tumor growth of melanoma by up-regulating PDCD4 in vivo.

Conclusions

CASC15 acts as an oncogene by negatively regulating PDCD4 expression via recruiting EZH2 and subsequently increasing H3K27me3 level. Together, our study indicates that CASC15/EZH2/PDCD4 may serve as a promising therapeutic target for melanoma intervention.

Simultaneous downregulation of miR-21 and miR-155 through oleuropein for breast cancer prevention and therapy

Breast cancer (BC) is the leading cause of cancer mortality in women worldwide. It recently was proven that miRNAs play a critical role in BC development. The use of natural agents for control of cancer by modulating miRNAs is promising. Oleuropein is a natural polyphenolic agent with anti-neoplastic properties and is well tolerated by humans. This study was undertaken to determine the therapeutic effects of oleuropein through modulation of master oncomiRs (miR-21 and miR-155) in BC cells. The present study provides the first link between miRNA and oleuropein as a mechanism in BC. MCF-7 cells were tested with and without oleuropein and the cell viability, apoptosis, and migration were examined. The effect of oleuropein on miR-21 and miR-155 expression was assessed through qRT-PCR. It was found that oleuropein induced apoptosis and retarded cell migration and invasion in a dose-dependent manner in the human MCF7 BC cell line. It was observed that oleuropein significantly decreased expression of both miR-21 and miR-155 over time in a dose-dependent manner. These results demonstrate that oleuropein is a potential therapeutic and preventive agent for BC. Oleuropein exhibits an anti-cancer effect by modulation of tumor suppressor gene expression, which is targeted by oncomiRs.

Circulating MicroRNA Biomarkers in Melanoma: Tools and Challenges in Personalised Medicine

Effective management of melanoma depends heavily on early diagnosis. When detected in early non-metastatic stages, melanoma is almost 100% curable by surgical resection, however when detected in late metastatic stages III and IV, 5-year survival rates drop to ~50% and 10–25%, respectively, due to limited efficacy of current treatment options. This presents a pressing need to identify biomarkers that can detect patients at high risk of recurrence and progression to metastatic disease, which will allow for early intervention and survival benefit. Accumulating evidence over the past few decades has highlighted the potential use of circulating molecular biomarkers for melanoma diagnosis and prognosis, including lactate dehydrogenase (LDH), S100 calcium-binding protein B (S100B) and circulating tumor DNA (ctDNA) fragments. Since 2010, circulating microRNAs (miRNAs) have been increasingly recognised as more robust non-invasive biomarkers for melanoma due to their structural stability under the harsh conditions of the blood and different conditions of sample processing and isolation. Several pre-analytical and analytical variables challenge the accurate quantification of relative miRNA levels between serum samples or plasma samples, leading to conflicting findings between studies on circulating miRNA biomarkers for melanoma. In this review, we provide a critical summary of the circulating miRNA biomarkers for melanoma published to date.

Involvement of HIF-1α-regulated miR-21, acting via the Akt/NF-κB pathway, in malignant transformation of HBE cells induced by cigarette smoke extract

Although the relationship between cigarette smoke and lung cancer has been widely studied, the molecular mechanism for cigarette smoke-induced lung cancer remains largely unclear. The present study investigated the roles of hypoxia-inducible factor (HIF)-1α and miR-21 in the malignant transformation of human bronchial epithelial (HBE) cells induced by cigarette smoke extract (CSE). In case of acute and chronic treatment of HBE cells, CSE increased the levels of HIF-1α, p-Akt, p-NF-κB, and miR-21 and decreased PTEN levels. The increased miR-21 levels induced by CSE were prevented by down-regulation of HIF-1α. Further, elevated miR-21 suppressed PTEN levels, which decreased the levels of p-Akt and p-NF-κB. However, those changes were attenuated in cells co-transfected with HIF-1α siRNA and an miR-21 mimic. Silencing of HIF-1α or NF-κB decreased colony formation and the invasion and migration capacities of CSE-transformed HBE cells; however, up-regulation of miR-21 reversed these effects. These results indicate that the oncogenic capacity of HIF-1α in regulation of miR-21-inhibited PTEN in a manner dependent on the Akt/NF-κB pathway, a process that is involved in the CSE-induced malignant transformation of HBE cells. Thus, the present research has established a new mechanism for cigarette smoke-induced lung carcinogenesis.

MicroRNA-342 Prohibits Proliferation and Invasion of Melanoma Cells by Directly Targeting Zinc-Finger E-Box-Binding Homeobox 1

As documented in numerous studies, microRNAs (miRNAs) play key roles in various biological processes associated with melanoma occurrence and development. In this study, we found that miRNA-342 (miR-342) was significantly downregulated in melanoma tissues and cell lines. Additionally, the ectopic expression of miR-342 prohibited the cell proliferation and invasion of melanoma. Moreover, zinc-finger E-box-binding homeobox 1 (ZEB1) was identified as a direct target gene of miR-342 in melanoma. Similar with the results induced by miR-342 overexpression, ZEB1 knockdown attenuated cell proliferation and invasion in melanoma. Furthermore, the restoration of ZEB1 expression reversed the suppressive effects of miR-342 on the proliferation and invasion of melanoma cells. These findings suggest that miR-342 may play tumor-suppressing roles in melanoma, at least partially, by directly inhibiting ZEB1 expression. Therefore, miR-342 may be developed as a potential candidate for the treatment of patients with this aggressive type of cancer.

MicroRNA-150 inhibitors enhance cell apoptosis of melanoma by targeting PDCD4

Malignant melanoma is a tumor with a high mortality rate. Previous studies have demonstrated that the oncogenesis of melanoma is associated with microRNA (miR)-150. However, the role of miR-150 in melanoma and its regulatory mechanisms are still unclear. In the present study, melanoma cancer tissues and adjacent normal tissues were obtained from 20 melanoma patients. The expression level of miR-150 in melanoma tissue and cell lines was detected by reverse transcription-quantitative polymerase chain reaction. miR-150 inhibitors/negative control were transfected into melanoma A375 cells in order to investigate the effects of miR-150 on cell proliferation, apoptosis, cell cycle migration and invasion using a Cell Counting Kit-8, colony formation, Hoechst 33528, flow cytometry, and Transwell assays. The association between miR-150 and programmed cell death protein-4 (PDCD4) was detected by a dual luciferase reporter assay. The functional role of PDCD4 in miR-150-affected melanoma cells was confirmed by small interfering (si)RNA knockdown. Results demonstrated that miR-150 was significantly upregulated and mRNA and protein expressions of PDCD4 were decreased in melanoma cancer tissues as compared with adjacent normal tissues. The level of PDCD4 was inversely associated with the level of miR-150. Transfection of miR-150 inhibitors suppressed cell proliferation, migration, and invasion, while the apoptosis of cells was promoted and G2/M cell arrest was induced. MiR-150 inhibitors enhanced the expression of caspase-8 and p21. The PDCD4 was identified as a direct target gene of miR-150. The effects of miR-150 inhibitors on apoptosis and apoptosis-associated proteins, including caspase-8 and p21, of A375 cells, were reversed following transfection of siRNA-PDCD4. Therefore, miR-150 inhibitors enhance cell apoptosis via upregulation of PDCD4-mediated activation of caspase-8 and p21. These findings demonstrate the potential for a promising therapeutic strategy in the management of melanoma.