Down-regulation of miRNA-106b inhibits growth of melanoma cells by promoting G1-phase cell cycle arrest and reactivation of p21/WAF1/Cip1 protein

The Potential of Circulating miR-193b, miR-146b-3p and miR-483-3p as Noninvasive Biomarkers in Cutaneous Melanoma Patients

Melanoma is a destructive skin disease with few therapeutic options in the developed stage and therefore there is a critical need for reliable biomarkers for early diagnosis. In this context, microRNAs could play an important role as diagnostic biomarkers. Three datasets with accession numbers GSE31568, GSE61741 and GSE20994 were downloaded from the Gene Expression Omnibus (GEO) database. MATLAB software was used to analyze differentially expressed miRNAs between cutaneous melanoma plasma samples and normal plasma samples (control). Plasma levels of miR-193b, miR-146b-3p and miR-483-3p were evaluated by the RT-PCR method. Furthermore, linear regression followed by receiver operating characteristic analyses was performed to estimate whether selected plasma miRNAs were able to distinguish between cases and controls. Finally, the data were analyzed by unpaired Mann-Whitney U test using Graph pad prism 8 computer software. Specifically, miR-193b and miR-146b-3p were downregulated in the plasma of melanoma patients compared with control groups which were decreased 5 × 10 6 -fold in miR-193b and 58-fold in miR-146b-3p, while miR-483-3p was upregulated 3.5-fold. After receiver operating characteristic (ROC) curve analysis, miR-193b with the most area under the curve (AUC: 1.00, 95% confidence interval 1.00-1.00, p < 0.0001) had the best discriminatory power, and miR-146b-3p had the large area under the curve (AUC: 0.96, 95% confidence interval 0.96-1.00, p < 0.0001) and consequently the high discriminatory power. Between these three miRNAs, miR-193b and miR-146b-3p had a high capacity to distinguish between melanoma patients and control groups that are appropriate to be applied in melanoma diagnosis as an early and noninvasive method.

The role of intestinal microbiota and microRNAs in the anti-inflammatory effects of cranberry: from pre-clinical to clinical studies

Cranberries have known anti-inflammatory properties, which extend their benefits in the context of several chronic diseases. These benefits highly rely on the polyphenol profile of cranberries, one of few foods rich in A-type proanthocyanidin (PAC). A-type PAC comprises flavan-3-ol subunits with an additional interflavan ether bond in the conformational structure of the molecule, separating them from the more commonly found B-type PAC. PACs with a degree of polymerization higher than three are known to reach the colon intact, where they can be catabolyzed by the gut microbiota and biotransformed into lower molecular weight organic acids that are available for host absorption. Gut microbiota-derived metabolites have garnered much attention in the past decade as mediators of the health effects of parent compounds. Though, the mechanisms underlying this phenomenon remain underexplored. In this review, we highlight emerging evidence that postulates that polyphenols, including ones derived from cranberries, and their metabolites could exert anti-inflammatory effects by modulating host microRNAs. Our review first describes the chemical structure of cranberry PACs and a pathway for how they are biotransformed by the gut microbiota. We then provide a brief overview of the benefits of microbial metabolites of cranberry in the intestinal tract, at homeostasis and in inflammatory conditions. Finally, we discuss the role of microRNAs in intestinal health and in response to cranberry PAC and how they could be used as targets for the maintenance of intestinal homeostasis. Most of this research is pre-clinical and we recognize that conducting clinical trials in this context has been hampered by the lack of reliable biomarkers. Our review discusses the use of miRNA as biomarkers in this context.

Inhibition of miR-214 expression by small molecules alleviates head and neck cancer metastasis by targeting ALCAM/TFAP2 signaling

Predominantly, head and neck cancer (HNC) is considered a regional disease and develops in the nasal cavity, oral cavity, tongue, pharynx, and larynx. In the advanced stage, the HNC spread into distant organs. By the time head and neck cancer diagnosed, the estimated metastasis is occurred in 10-40% cases. The most important vital organs affected by distant metastasis are the lungs, bones, and liver. Despite several advancements in chemotherapies, no significant changes are observed as 5-year survival rate remains the same. Therefore, it is crucial to decipher molecular mechanisms contributing to the metastatic dissemination of head and neck cancer. Here, we tested a novel ALCAM/TFAP2 signaling by targeting multidisciplinary miR-214 expression in head and cancer cells. Our results revealed that HNC cell lines (CAL27, SCC-9, SCC-4, and SCC-25) exhibit higher expression of miR-214 compared with normal human bronchial epithelial (NHBE) cells. Higher expression of miR-214 drives the invasive potential of these cell lines. Down-regulation of miR-214 in CAL27 and SCC-9 cells either using an anti-miR-214 inhibitor (50nM) or a small molecule of green tea (EGCG) inhibited cell invasion. Treating CAL27 and SCC-9 cells with EGCG also reduces ALCAM expression, a key activated leukocyte cell adhesion molecule, potentially blocking mesenchymal phenotype. Dietary administration of EGCG significantly inhibits distant metastasis of SCC-9 cells into the lungs, liver, and kidneys. Our results also demonstrate that the reduction of miR-214 expression influences in vitro cell movement and extravasation, as evident by reduced CD31 expression, a neovascularization marker. Together, these studies suggest that identifying bioactive molecules that can inhibit distant metastasis regulated by the miRNAs may provide potent interventional approaches and a better understanding of the complex functions of miRNAs and their therapeutic targets for clinical application.

MicroRNA as a Diagnostic Tool, Therapeutic Target and Potential Biomarker in Cutaneous Malignant Melanoma Detection—Narrative Review

Melanoma is the most serious type of skin cancer, causing a large majority of deaths but accounting for only ~1% of all skin cancer cases. The worldwide incidence of malignant melanoma is increasing, causing a serious socio-economic problem. Melanoma is diagnosed mainly in young and middle-aged people, which distinguishes it from other solid tumors detected mainly in mature people. The early detection of cutaneous malignant melanoma (CMM) remains a priority and it is a key factor limiting mortality. Doctors and scientists around the world want to improve the quality of diagnosis and treatment, and are constantly looking for new, promising opportunities, including the use of microRNAs (miRNAs), to fight melanoma cancer. This article reviews miRNA as a potential biomarker and diagnostics tool as a therapeutic drugs in CMM treatment. We also present a review of the current clinical trials being carried out worldwide, in which miRNAs are a target for melanoma treatment.

Differentially deregulated microRNAs contribute to ultraviolet radiation-induced photocarcinogenesis through immunomodulation: An-analysis of microRNAs expression profiling

MicroRNAs (miRNAs) are short non-coding RNA molecules (18-25 nucleotides) that regulate several fundamental biological processes. Emerging evidence has shown more than 1500 miRNAs functions in the cell cycle, proliferation, apoptosis, oxidative stress, immune response, DNA damage, and epigenetics alterations. miRNAs are bidirectionally in nature and act as a tumor suppressor and as an oncogene through crosstalk between tumor cells and immune cells. Although the roles of miRNAs in several cancers are well studied, little is known about ultraviolet B (UVB) radiation-induced skin cancer. Here, we performed a comprehensive screening of 1281 miRNAs in tumor tissues and compared their expression with normal skin. Our results demonstrate that the expression levels of 587 miRNAs were altered in tumor tissues compared to their expression in normal skin. The expression of 337 miRNAs was upregulated from 1.5-12 folds, while the expression of 250 miRNAs was downregulated up to 1.5-10 folds in tumors. Further, intraperitoneal injection of a mimic of down-regulated miR-15b (30nM) and an inhibitor of upregulated miR-133a (20nM) protect UVB-induced suppression of contact hypersensitivity (CHS) response. In conclusion, we identified a network of altered miRNAs in tumors that can serve as prognostic biomarkers and therapeutic targets to manage photocarcinogenesis effectively.

LncRNA LNCOC1 is Upregulated in Melanoma and Serves as a Potential Regulatory Target of miR-124 to Suppress Cancer Cell Invasion and Migration

Background

A cascade of genes and pathways have been reported in the precise regulation of malignant melanoma (MM). Previous study has demonstrated that lncRNA LNCOC1 is an oncogenic factor in the pathogenesis and development of various cancers. The present study explored the functionalities of LNCOC1 and its interactions with miR-124 in MM.

Methods

A total of 65 melanoma patients were enrolled in this study. The expression of LNCOC1 and miR-124 after cell transfection were detected by RT-qPCR. The migration rates of SK-MEL-3 and A375 cells after transient transfection with LNCOC1 expression vector and miR-124 mimic was detected by trans-well assay.

Results

LNCOC1 was accumulated to high levels in melanoma, and it was significantly correlated with the low survival rate of melanoma patients. Our bioinformatics data showed that miR-124 could target LNCOC1. Overexpression of miR-124 could downregulate LNCOC1. However, up-regulated the expression of LNCOC1 did not affect the expression of miR-124. Our correlation analysis also revealed that the expression of LNCOC1 and miR-124 were inversely correlated in both melanoma tissues and non-tumor tissues. The trans-well invasion and migration assays indicated that overexpression of miR-124 inhibited the melanoma cell invasion and migration. However, overexpression of LNCOC1 promoted melanoma cell invasion and migration.

Conclusion

LNCOC1 is upregulated in melanoma, which can be considered as a potential target of miR-124 in modulating melanoma cell invasion and migration. LNCOC1 may also be an interfering target of MM therapy.

MicroRNAs Involved in Oxidative Stress Processes Regulating Physiological and Pathological Responses

Oxidative stress influences several physiological and pathological cellular events, including cell differentiation, excessive growth, proliferation, apoptosis, and the inflammatory response. Therefore, oxidative stress is involved in the pathogenesis of various diseases, including pulmonary fibrosis, epilepsy, hypertension, atherosclerosis, Parkinson's disease, cardiovascular disease, and Alzheimer's disease. Recent studies have shown that several microRNAs (miRNAs) are involved in developing various diseases caused by oxidative stress and that miRNAs may be helpful to determine the inflammatory characteristics of immune responses during infection and disease. This review describes the known effects of miRNAs on reactive oxygen species to induce oxidative stress and the miRNA regulatory mechanisms involved in the uncoupling of Keap1-Nrf2 complexes. Finally, we summarized the functions of miRNAs in several antioxidant genes. Understanding the crosstalk between miRNAs and oxidative stress-inducing factors during physiological and pathological cellular events may have implications for designing more effective treatments for immune diseases.

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.

Circular RNA circ_0079593 enhances malignant melanoma progression by the regulation of the miR-573/ABHD2 axis

BACKGROUND

Malignant melanoma is the most fatal type of skin tumor. Circular RNAs (circRNAs) have been implicated in the malignant progression of melanoma.

OBJECTIVE

The main purpose of this paper was to identify the precise parts of circ_0079593 in the malignant progression of melanoma.

METHODS

The levels of circ_0079593, miR-573 and abhydrolase domain containing 2 (ABHD2) were determined by quantitative real-time polymerase chain reaction (qRT-PCR) and western blot. Cell proliferation, colony formation, cell cycle progression, apoptosis, migration, and invasion were evaluated using the Cell Counting Kit-8 (CCK-8), colony formation, flow cytometry, and transwell assays, respectively. Targeted correlations among circ_0079593, miR-573 and ABHD2 were confirmed by dual-luciferase reporter, RNA immunoprecipitation (RIP) and RNA pull-down assays. Animal studies were performed to assess the role of circ_0079593 in vivo.

RESULTS

Our data showed that circ_0079593 level was up-regulated in melanoma tissues and cells. The knockdown of circ_0079593 suppressed cell proliferation, cell cycle progression, migration, invasion, and enhanced apoptosis in vitro and inhibited tumor growth in vivo. Mechanistically, circ_0079593 directly targeted miR-573, and circ_0079593 controlled ABHD2 expression by miR-573. MiR-573 mediated the regulation of circ_0079593 on melanoma cell progression in vitro. Moreover, ABHD2 was a functional target of miR-573 in regulating melanoma cell progression in vitro.

CONCLUSION

Our findings identified that the knockdown of circ_0079593 suppressed melanoma progression at least partially through targeting the miR-573/ABHD2 axis, providing evidence for developing circ_0079593 as a promising therapeutic target for melanoma treatment.

Flavonoid display ability to target microRNAs in cancer pathogenesis

MicroRNAs (miRNAs) are non-coding, conserved, single-stranded nucleotide sequences involved in physiological and developmental processes. Recent evidence suggests an association between miRNAs' deregulation with initiation, promotion, progression, and drug resistance in cancer cells. Besides, miRNAs are known to regulate the epithelial-mesenchymal transition, angiogenesis, autophagy, and senescence in different cancer types. Previous reports proposed that apart from the antioxidant potential, flavonoids play an essential role in miRNAs modulation associated with changes in cancer-related proteins, tumor suppressor genes, and oncogenes. Thus, flavonoids can suppress proliferation, help in the development of drug sensitivity, suppress metastasis and angiogenesis by modulating miRNAs expression. In the present review, we summarize the role of miRNAs in cancer, drug resistance, and the chemopreventive potential of flavonoids mediated by miRNAs. The potential of flavonoids to modulate miRNAs expression in different cancer types demonstrate their selectivity and importance as regulators of carcinogenesis. Flavonoids as chemopreventive agents targeting miRNAs are extensively studied in vitro, in vivo, and pre-clinical studies, but their efficiency in targeting miRNAs in clinical studies is less investigated. The evidence presented in this review highlights the potential of flavonoids in cancer prevention/treatment by regulating miRNAs, although further investigations are required to validate and establish their clinical usefulness.

IER2-induced senescence drives melanoma invasion through osteopontin

Expression of the immediate-early response gene IER2 has been associated with the progression of several types of cancer, but its functional role is poorly understood. We found that increased IER2 expression in human melanoma is associated with shorter overall survival, and subsequently investigated the mechanisms through which IER2 exerts this effect. In experimental melanoma models, sustained expression of IER2 induced senescence in a subset of melanoma cells in a p53/MAPK/AKT-dependent manner. The senescent cells produced a characteristic secretome that included high levels of the extracellular phosphoglycoprotein osteopontin. Nuclear localization of the IER2 protein was critical for both the induction of senescence and osteopontin secretion. Osteopontin secreted by IER2-expressing senescent cells strongly stimulated the migration and invasion of non-senescent melanoma cells. Consistently, we observed coordinate expression of IER2, p53/p21, and osteopontin in primary human melanomas and metastases, highlighting the pathophysiological relevance of IER2-mediated senescence in melanoma progression. Together, our study reveals that sustained IER2 expression drives melanoma invasion and progression through stimulating osteopontin secretion via the stochastic induction of senescence.

Usefulness of serum miR-1246/miR-106b ratio in patients with esophageal squamous cell carcinoma

The function of microRNAs (miRs) is associated with the development and progression of various malignancies, with miRs presenting stably in the serum. The current study assessed the role of miR-1246 and miR-106b in the serum of patients with esophageal squamous cell carcinoma (ESCC). A comprehensive microarray analysis of miR expression was performed using the serum of patients with ESCC, which were subsequently validated via reverse transcription-quantitative PCR. A total of 55 test samples were obtained from Chiba University and 101 validation samples were gained from Chiba Cancer Center. The results revealed that miR-1246 expression significantly increased and miR-106b expression significantly decreased in each cohort. Receiver operating characteristic analysis revealed that the area under the curve (AUC) value of miR-1246 was 0.816 (sensitivity, 72.7%; specificity, 69.2%) and 0.779 (sensitivity, 71.3%; specificity, 70.6%) for the test and validation cohorts, respectively. The AUC of miR-106b was 0.716 (sensitivity, 65.5%; specificity, 61.6%) and 0.815 (sensitivity, 74.3%; specificity, 73.5%), respectively. In addition, the AUC of the miR-1246/miR-106b ratio was 0.901 (sensitivity, 80.0%; specificity, 80.0%) and 0.903 (sensitivity, 82.1%; specificity, 82.3%), respectively, which indicated a higher diagnostic ability compared with that of miR-1246 or miR-106b alone. The high miR-1246/miR-106b ratio group was associated with clinicopathological factors such as depth of invasion, progression, lymph node metastasis, and poor prognosis. Therefore, effective biomarkers may be generated by combining individual miRs obtained by comprehensive analysis of ESCC patient sera.

miR‑95 promotes osteosarcoma growth by targeting SCNN1A

Osteosarcoma (OS) is a common malignant bone tumor, presenting particularly in children and young adults, and accounts for approximately 19% of all malignant bone cancers. Despite advances in OS treatment, long-term prognosis remains poor. miRNAs are non-coding single-stranded RNAs ~22 nucleotides in length. Increasing evidence suggests that numerous miRNAs may play critical roles in tumorigenesis and tumor progression; however, the role of miR-95 in OS has not been examined. In the present study, we investigated the role of miR-95 in OS using in vitro and in vivo models and publicly available expression data. Our findings indicate that abnormal miR-95 expression occurs in OS, according to the Gene Expression Omnibus (GEO) database. The miR-95 inhibitor reduced cell proliferation and promoted apoptosis in OS cell lines as detected by EdU staining, TUNEL staining and flow cytometry. Furthermore, a dual luciferase reporter assay revealed that miR-95 regulates the cell cycle of OS cells and apoptosis by targeting sodium channel epithelial 1α subunit (SCNN1A). Additionally, miR-95 antagomir suppressed the growth of U2OS xenograft tumors in a mouse model. In summary, our results suggest that miR-95 induces OS growth in vitro and in vivo by targeting SCNN1A. Our results help clarify the mechanism underlying the miR-95-mediated effects on OS tumor growth, thus potentially establishing it as a diagnostic target.

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.

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.

LncRNA XIST, as a ceRNA of miR-204, aggravates lipopolysaccharide-induced acute respiratory distress syndrome in mice by upregulating IRF2

BACKGROUND

Acute respiratory distress syndrome (ARDS) is a common clinical syndrome with high a mortality rate, which is associated with diffuse alveolar injury and capillary endothelial damage. In recent years, numerous studies have been performed to explore the roles of long non-coding RNAs (lncRNAs) in various diseases in which lncRNA serves as a microRNA (miRNA) sponge to regulate targeted gene expression. However, whether lncRNAs participate in ARDS progression remains unclear.

MATERIALS/METHODS

The dual-luciferase reporter assay was employed to identify the interaction between lncRNA XIST and miR-204, as well as the correlation between miR-204 and interferon regulatory factor 2 (IRF2). Then, PaO₂/FiO₂ was determined in lipopolysaccharide (LPS)-induced ARDS. In addition, the concentrations of cytokines, including IFN-γ, IL-6, IL-17, TNF-α, IL-1β, and IL-6R were analyzed by ELISA. lncRNA XIST, miR-204, and IRF2 levels were determined by qRT-PCR assay, and the IRF2 expression was evaluated by western blot. Furthermore, levels of inflammation and conditions of alveoli were evaluated by hematoxylin (H&E)-staining in LPS-induced ARDS.

RESULTS

Our findings indicated that lncRNA XIST served as a sponge for miR-204. miR-204 directly regulated IRF2, andlncRNA XIST upregulated IRF2 expression by targeting miR-204. LncRNA XIST and miR-204 inhibitors significantly decreased the PaO₂/FiO₂ ratio, whereas miR-204 and silencing of IRF2 significantly increased the PaO₂/FiO₂ ratio in LPS-induced ARDS. In addition, lncRNA XIST and miR-204 inhibitors significantly increased levels of IFN-γ, IL-6, IL-17, TNF-α, IL-1β, and IL-6R, whereas miR-204 and silencing of IRF2 dramatically decreased related cytokines in LPS-induced ARDS. Furthermore, we demonstrated that lncRNA XIST and miR-204 inhibitors aggravated inflammatory cell infiltration, alveolitis, and the degree of fibrosis, whereas miR-204 and silencing of IRF2 alleviated inflammation and conditions of the alveoli.

CONCLUSION

In this study, we verified that lncRNA XIST serves as a sponge for miR-204 to aggravate LPS-induced ARDS in mice by upregulating IRF2.

E2F7, EREG, miR-451a and miR-106b-5p are associated with the cervical cancer development

PURPOSE

We aimed to seek the crucial genes or microRNAs (miRNA) correlated with the cervical cancer development.

METHODS

The miRNA profiling GSE30656 and gene expression profiling GSE63514 were obtained from Gene Expression Omnibus database. Differentially expressed microRNAs (DEMiRs) and differentially expressed genes (DEGs) were screened. Then target genes of DEMiRs were obtained and matched with DEGs to obtain interaction pairs between DEMiRs and DEGs. Gene Ontology-biological process and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were conducted for DEGs and DEMiRs in the DEMiRs-DEGs pairs. The DEMiRs-DEGs regulatory network, protein-protein interaction network and transcription factor (TF)-target regulatory network were constructed. Ultimately, long non-coding RNAs (lncRNAs) associated with DEMiRs were obtained, and then lncRNA-miRNA-target ceRNA network was established.

RESULTS

Total 18 DEMiRs and 620 DEGs were identified. DEMiRs were enriched in 35 KEGG pathways, such as PI3K-Akt signaling pathway (involving miR-451a). DEGs were enriched in various functions, such as DNA replication (involving E2F7) and angiogenesis (involving EREG). There were 120 nodes and 216 interaction pairs in the DEMIR-DEG regulatory network, and miR-106b-5p has the greatest degree. EREG and E2F7 were regulated by miR-451a and miR-148a-3p, respectively. Besides, E2F7 was identified in the TF-target regulatory network, regulating CDC6. There were 15 lncRNAs, 11 miRNAs and 90 DEGs in the ceRNA network. Specially, miR-148a-3p was interacted with lncRNA HOTAIR in the ceRNA network.

CONCLUSION

E2F7, EREG, miR-451a and miR-106b-5p were likely to be related to the cervical cancer development.

Grape seed proanthocyanidins inhibit proliferation of pancreatic cancer cells by modulating microRNA expression

MicroRNAs (miRNAs) are small non-coding RNAs of 18–25 nucleotides that modulate gene expression at the post-transcriptional level. Grape seed proanthocyanidins (GSPs), which are biologically active components in grape seeds, have been demonstrated to exhibit anticancer effects. The current study investigated whether GSPs can regulate miRNA expression and the possible anticancer molecular mechanisms of GSPs. Pancreatic cancer (PC) cell samples, SS3, SS12 and SS24, were treated with 20 µg/ml GSPs for 3, 12 and 24 h, respectively. Control samples, SC3, SC12 and SC24, were also prepared. Using miRNA-seq, transcriptome analysis identified 24, 83 and 83 differentially expressed (DE) miRNAs in SS3 vs. SC3, SS12 vs. SC12 and SS24 vs. SC24, respectively. This indicated that treatment with GSPs could modulate the expression of miRNAs. Subsequently, 74, 598 and 1,204 target genes for the three sets of DE miRNAs were predicted. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis revealed that multiple target genes were associated with the proliferation and apoptosis of PC cells. In addition, a network was constructed of the DE miRNAs and the target genes associated with PC. The associations identified suggested that treatment with GSPs may inhibit the proliferation of PC cells through the modulation of miRNA expression.

Prognostic relevance of proliferation-related miRNAs in pancreatic neuroendocrine neoplasms

OBJECTIVE

Pancreatic neuroendocrine neoplasms (PanNENs) are rare tumors arising from the endocrine pancreas; however, their prognosis differs significantly upon their proliferative state, which is characterized by histopathological grading. MiRNAs are small, noncoding RNAs posttranscriptionally regulating gene expression. Our aim was to identify miRNAs with altered expression upon proliferation which can be used as prognostic biomarkers in PanNENs.

METHODS

MiRNA expression profiles of 40 PanNENs were downloaded from Gene Expression Omnibus and were reanalyzed upon tumor grades (discovery cohort). Results of the reanalysis were confirmed by qRT-PCR analysis of five miRNAs on an independent validation cohort of 63 primary PanNEN samples. Cox proportional hazards survival regression models were fit for both univariate and multivariate analysis to determine the miRNAs’ effect on progression-free and overall survival.

RESULTS

Nineteen miRNAs displayed differential expression between tumor grades. The altered expression of three out of five chosen miRNAs was successfully validated; hsa-miR-21, hsa-miR-10a and hsa-miR-106b were upregulated in more proliferative PanNENs compared to Grade 1 tumors. In univariate analysis, higher expression of tissue hsa-miR-21, hsa-miR-10a and hsa-miR-106b of primary PanNENs predicted worse progression-free and overall survival; however, multivariate analysis only confirmed the expression of hsa-miR-21 as an independent prognostic factor.

CONCLUSIONS

The expression of hsa-miR-106b, hsa-miR-10a and especially hsa-miR-21 has prognostic relevance regarding progression-free and overall survival in patients with PanNENs.

The emerging roles of the polycistronic miR-106b∼25 cluster in cancer - A comprehensive review

MicroRNAs (miRNAs) are short, non-coding RNA molecules that regulate gene expression at the post-transcriptional level by inhibiting translation and decreasing the stability of the targeted transcripts. Over the last two decades, miRNAs have been recognized as important regulators of cancer cell biology, acting either as oncogenes or tumor suppressors. The polycistronic miR-106b∼25 cluster, located within an intron of MCM7 gene, consists of three highly conserved miRNAs: miR-25, miR-93 and miR-106b. A constantly growing body of evidence indicates that these miRNAs are overexpressed in numerous human malignancies and regulate multiple cellular processes associated with cancer development and progression, including: cell proliferation and survival, invasion, metastasis, angiogenesis and immune evasion. Furthermore, recent studies revealed that miR-106b∼25 cluster miRNAs modulate cancer stem cells characteristics and might promote resistance to anticancer therapies. In light of these novel discoveries, miRNAs belonging to the miR-106b∼25 cluster have emerged as key oncogenic drivers as well as potential biomarkers and plausible therapeutic targets in different tumor types. Herein, we comprehensively review novel findings on the roles of miR-106b∼25 cluster in human cancer, and provide a broad insight into the molecular mechanisms underlying its oncogenic properties.

RETRACTED: Long non-coding RNA UCA1 targets miR-185-5p and regulates cell mobility by affecting epithelial-mesenchymal transition in melanoma via Wnt/β-catenin signaling pathway

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. Several figures presented in the manuscript appear to have been doctored. The journal has tried to contact the authors of this article but at the time of publication of this notice has not received any response. As there is no explanation for the picture manipulations, the Editor-in-Chief of Gene has lost confidence in the validity of this work and has decided to retract it.

Serum miR-106b upregulation predicts poor prognosis in patients with colorectal cancer

Colorectal cancer (CRC) is one of most common cancers and a leading cause of cancer-related death around the world. Identification of reliable biomarkers contributes to facilitate disease detection of this malignancy. This study aimed to explore the serum miR-106b expression in CRC and its potential clinical significance. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to measure the miR-106b expression levels in the serum from 122 CRC patients, 40 advanced adenomas and 50 healthy individuals. Serum miR-106b levels were significantly increased in CRC patients compared to healthy controls. Elevated serum miR-106b expression occurred more frequently in CRC patients with lymph node metastasis and distant metastasis. Moreover, receiver operating characteristic (ROC) curve analysis revealed that serum miR-106b could well discriminate CRC patients from healthy controls. In addition, miR-106b levels were greatly reduced in post-operative samples from CRC cases with early clinical stage. Furthermore, increased miR-106b expression was positively correlated with aggressive clinical variables and poor prognosis. Finally, serum miR-106b was identified as an independent prognostic predictor for CRC. Collectively, our findings suggest serum miR-106b might potentially serve as a promising biomarker in the diagnosis and prognosis of CRC.

Functionalized carbon nanotubes as emerging delivery system for the treatment of cancer

In recent time, carbon nanotubes (CNTs) have gained vital importance for pharmaceutical formulation scientist for delivering drugs and genes, owing to their excellent surface properties. For example, their aspect ratio is thought to be responsible for their excellent cell penetration aptitude; anisotropic conductivity/semi-conductivity along their axis is ideal for integration with nervous and muscular tissue; an ultrahigh surface area maximizes their ability to "talk" with biological matter; the hollow interior provides an enormous cargo-carrying capacity for drug delivery; and their exteriors are readily functionalized to permit tailoring of solubility and biological recognition. Despite their immense capabilities for the delivery of drugs, genes and other biomedically essential materials, there use is restricted primarily because of the severe toxicity. However, the reactive nature of the surface of the CNTs allowed attaching the guest molecules (drug, siRNA, and diagnostics) of interest which helps in increasing the biocompatibility of these novel nanocarriers. As per the need, CNTs can be modified with peptides, organic molecules, carbohydrates, polymers and used mainly for cancer targeting and tumor cell accumulation. This review expounds different functionalization strategies employed for CNTs that created new opportunities for scientists to improve the potential of delivered therapeutics.

WITHDRAWN: Serum miR-106b upregulation predicts poor prognosis in patients with colorectal cancer

Ahead of Print article withdrawn by publisher.

MicroRNA-5110 regulates pigmentation by cotargeting melanophilin and WNT family member 1

Mammalian pigmentation requires the production of melanin by melanocytes and its transfer to neighboring keratinocytes. These complex processes are regulated by several molecular pathways. Melanophilin ( MLPH) and WNT family member 1 ( WNT1), known to be involved in melanin transfer and melanin production, respectively, were predicted to be targets of microRNA-5110 using bioinformatics. In the current study, we investigated the effects of microRNA-5110 on pigmentation in alpaca ( Vicugna pacos) melanocytes. In situ hybridization identified high levels of microRNA-5110 in the cytoplasm of alpaca melanocytes. Luciferase activity assays confirmed that MLPH and WNT1 were targeted by microRNA-5110 in these cells. Overexpression and knockdown of microRNA-5110 in alpaca melanocytes downregulated and upregulated MLPH and WNT1 expression at the mRNA and protein levels, respectively. In addition, overexpression and knockdown of microRNA-5110 in alpaca melanocytes decreased and increased, respectively, the mRNA levels of the melanin transfer-related genes, rat sarcoma (RAS)-associated binding ( RAB27a) and myosin 5a ( MYO5a); the mRNA levels of microphthalmia-associated transcription factor ( MITF), tyrosinase ( TYR), and tyrosinase-related protein ( TYRP) 1; and the production of total alkali melanin and pheomelanin. In contrast, overexpression and knockdown of microRNA-5110 increased and decreased the mRNA levels of TYRP2, respectively. Overexpression of microRNA-5110 also increased eumelanin. These results indicate that microRNA-5110 regulates pigmentation in alpaca melanocytes by directly targeting MLPH and WNT1 to affect eumelanin production and transfer.-Yang, S., Liu, B., Ji, K., Fan, R., Dong, C. MicroRNA-5110 regulates pigmentation by cotargeting melanophilin and WNT family member 1.

Grape seed procyanidin extract against lung cancer: the role of microrna-106b, bioavailability, and bioactivity

MiR-106b is an oncomir and a potential target for anti-cancer therapy. We hypothesize that grape seed procyanidin extract (GSE) exerts antineoplastic effects on lung cancer through modulations of miR-106b and its downstream target. We found that GSE significantly down-regulated miR-106b in a variety of lung neoplastic cells and increased cyclin-dependent kinase inhibitor 1A (CDKN1A) mRNA and protein (p21) levels. Transfection of miR-106b mimics reversed the up-regulations of CDKN1A mRNA and p21, abrogated the GSE induced anti-proliferative and anti-invasive properties in lung cancer cells. Oral gavage of leucoselect phytosome (LP), a standardized GSE to athymic nude mice down-regulated MIR106B mRNA and miR-106b expressions, and increased CDKN1A mRNA expression in tumor xenografts, correlating to significant reduction of tumor growth. To assess bioavailability, GSE and metabolites in plasma levels, between 60-90 minutes after gavage of LP were measured by LC/MS at treatment week 4 and 8. A novel bioactivity assay was also developed using lung homogenates from treated mice co-cultured with human lung cancer cells. LP-treated mouse lung homogenates significantly reduced proliferations of various lung cancer cells. Our findings reveal novel antineoplastic mechanisms by GSE, further define the pharmacokinetics and pharmacodynamics of LP, and support the continued investigation of LP against lung cancer.

Chemoprevention of intestinal tumorigenesis by the natural dietary flavonoid myricetin in APCMin/+ mice

Myricetin is a natural dietary flavonoid compound. We evaluated the efficacy of myricetin against intestinal tumorigenesis in adenomatous polyposis coli multiple intestinal neoplasia (APCMin/+) mice. Myricetin was given orally once a day for 12 consecutive weeks. APCMin/+ mice fed with myricetin developed fewer and smaller polyps without any adverse effects. Histopathological analysis showed a decreased number of dysplastic cells and degree of dysplasia in each polyp. Immunohistochemical and western blot analysis revealed that myricetin selectively inhibits cell proliferation and induces apoptosis in adenomatous polyps. The effects of myricetin were associated with a modulation the GSK-3β and Wnt/β-catenin pathways. ELISA analysis showed a reduced concentration of pro-inflammatory cytokines IL-6 and PGE2 in blood, which were elevated in APCMin/+ mice. The effect of myricetin treatment was more prominent in the adenomatous polyps originating in the colon. Further studies showed that myricetin downregulates the phosphorylated p38 MAPK/Akt/mTOR signaling pathways, which may be the mechanisms for the inhibition of adenomatous polyps by myricetin. Taken together, our data show that myricetin inhibits intestinal tumorigenesis through a collection of biological activities. Given these results, we suggest that myricetin could be used preventatively to reduce the risk of developing colon cancers.

Reactivation of epigenetically silenced miR-124 reverses the epithelial-to-mesenchymal transition and inhibits invasion in endometrial cancer cells via the direct repression of IQGAP1 expression

Overexpression of IQGAP1 and microRNA (miRNA) dysregulation are frequent in human tumors, but little is known about the role of IQGAP1 and its relationship to miRNA in endometrial carcinogenesis. We demonstrate that IQGAP1 activates the epithelial–mesenchymal transition (EMT) program and that miR-124 directly represses IQGAP1 expression in endometrial cancer (EC) cells. The overexpression of IQGAP1 stimulates EMT features and enhances migration, invasion and proliferation of EC cells, whereas knocking down IQGAP1 expression reverses EMT and inhibits these malignant properties. Using miRNA microarray profiling, we identified 29 miRNAs (let-7b, let-7f, miR-10b, miR-15b, miR-23a, miR-24, miR-25, miR-27a, miR-29b, miR-30a-5p, miR-34a, miR-124, miR-127, miR-130b, miR-148a, miR-155, miR-191*, miR-194, miR-224, miR-362, miR-409-3p, miR-422b, miR-424, miR-453, miR-497, miR-518d, miR-518f*, miR-526a and miR-656) that are significantly down-regulated in an in vitro-selected highly invasive derivative cell line (HEC-50-HI) relative to the parental HEC-50 cells. We further identified miR-124 as a direct regulator of IQGAP1 in EC cells. Enforced expression of miR-124 suppresses EC cell invasion and proliferation. The expression of IQGAP1 mRNA was significantly elevated in EC tissues, while the expression of miR-124 was decreased. The downregulation of miR-124 correlates with a poor survival outcome for patients with EC. Treating EC cells with the demethylating agent 5-aza-2′-deoxycytidine increased miR-124 expression and down-regulated IQGAP1 levels. Our data suggest that IQGAP1 promotes EMT, migration and invasion of EC cells. MiR-124, a novel tumor suppressor miRNA that is epigenetically silenced in EC, can reverse EMT and the invasive properties, by attenuating the expression of the IQGAP1 oncogene.

MicroRNA-Directed Cancer Therapies: Implications in Melanoma Intervention

Acquired tumor resistance to cancer therapies poses major challenges in the treatment of cancers including melanoma. Among several signaling pathways or factors that affect neocarcinogenesis, cancer progression, and therapies, altered microRNAs (miRNAs) expression has been identified as a crucial player in modulating the key pathways governing these events. While studies in the miRNA field have grown exponentially in the last decade, much remains to be discovered, particularly with respect to their roles in cancer therapies. Since immune and nonimmune signaling cascades prevail in cancers, identification and evaluation of miRNAs, their molecular mechanisms and cellular targets involved in the underlying development of cancers, and acquired therapeutic resistance would help in devising new strategies for the prognosis, treatment, and an early detection of recurrence. Importantly, in-depth validation of miRNA-targeted molecular events could lead to the development of accurate progression-risk biomarkers, improved effectiveness, and improved patient responses to standard therapies. The current review focuses on the roles of miRNAs with recent updates on regulated cell cycle and proliferation, immune responses, oncogenic/epigenetic signaling pathways, invasion, metastasis, and apoptosis, with broader attention paid to melanomagenesis and melanoma therapies.

MicroRNA‑512‑3p is upregulated, and promotes proliferation and cell cycle progression, in prostate cancer cells

Prostate cancer (PCa) is the most commonly diagnosed cancer in males worldwide. MicroRNAs (miRNAs/miRs) are small non‑coding RNAs that participate in the regulation of various biological processes by regulating post‑transcriptional gene expression. However, whether dysregulation of miRNA expression may be associated with the carcinogenesis of PCa remains to be elucidated. The present study identified differentially expressed miRNAs in PCa by analyzing two publicly available gene expression datasets, GSE14857 and GSE21036. The results demonstrated that miR‑512‑3p was significantly upregulated in PCa. Furthermore, the present study explored the molecular functions of miR‑512‑3p in PCa, and demonstrated that overexpression of miR‑512‑3p promoted PCa cell proliferation and reduced G1 phase cell cycle arrest in PCa. These results indicated that miR‑512‑3p may act as an oncogene in PCa. To the best of our knowledge, this is the first study revealed the molecular functions of miR‑512‑3p in PCa. To obtain valuable insights into the potential mechanisms of miR‑512‑3p, bioinformatics analyses were performed to identify the targets of miR‑512‑3p. Kyoto Encyclopedia of Genes and Genomes pathway and Gene Ontology category analyses revealed that miR‑512‑3p may be associated with the mitogen‑activated protein kinase signaling pathway and numerous biological processes, including cell adhesion, cell proliferation, cell cycle and apoptosis. These results suggested that miR‑512‑3p may be considered a potential diagnostic and therapeutic target of PCa.

Proanthocyanidins and hydrolysable tannins: occurrence, dietary intake and pharmacological effects

Tannins are a heterogeneous group of high MW, water-soluble, polyphenolic compounds, naturally present in cereals, leguminous seeds and, predominantly, in many fruits and vegetables, where they provide protection against a wide range of biotic and abiotic stressors. Tannins exert several pharmacological effects, including antioxidant and free radical scavenging activity as well as antimicrobial, anti-cancer, anti-nutritional and cardio-protective properties. They also seem to exert beneficial effects on metabolic disorders and prevent the onset of several oxidative stress-related diseases. Although the bioavailability and pharmacokinetic data for these phytochemicals are still sparse, gut absorption of these compounds seems to be inversely correlated with the degree of polymerization. Further studies are mandatory to better clarify how these molecules and their metabolites are able to cross the intestinal barrier in order to exert their biological properties. This review summarizes the current literature on tannins, focusing on the main, recently proposed mechanisms of action that underlie their pharmacological and disease-prevention properties, as well as their bioavailability, safety and toxicology.

LINKED ARTICLES

This article is part of a themed section on Principles of Pharmacological Research of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.11/issuetoc.

miR-337 can be a key negative regulator in melanoma

Incidence of melanoma is increasing annually worldwide. There remains a lack of suitable treatment methods which can significantly improve the 5-year survival rates of patients. It is established that micro RNAs (miRNAs) have important roles in the diagnosis and treatment of cancer. MiR-337 had been reported to regulate the development of variety of cancers, as a cancer suppressive factor. In our research we found that miR-337 had a lower expression in melanoma than adjacent tissues. The patients who had a lower miR-337 also got a worse survival. MiR-337 could target STAT3 to regulate the occurrence and development of melanoma.  In summary, our findings suggest that the miR-337/STAT3 axis may serve as a potential target for the treatment of melanoma.

Cryptolepine, a Plant Alkaloid, Inhibits the Growth of Non-Melanoma Skin Cancer Cells through Inhibition of Topoisomerase and Induction of DNA Damage

Topoisomerases have been shown to have roles in cancer progression. Here, we have examined the effect of cryptolepine, a plant alkaloid, on the growth of human non-melanoma skin cancer cells (NMSCC) and underlying mechanism of action. For this purpose SCC-13 and A431 cell lines were used as an in vitro model. Our study reveals that SCC-13 and A431 cells express higher levels as well as activity of topoisomerase (Topo I and Topo II) compared with normal human epidermal keratinocytes. Treatment of NMSCC with cryptolepine (2.5, 5.0 and 7.5 µM) for 24 h resulted in marked decrease in topoisomerase activity, which was associated with substantial DNA damage as detected by the comet assay. Cryptolepine induced DNA damage resulted in: (i) an increase in the phosphorylation of ATM/ATR, BRCA1, Chk1/Chk2 and γH2AX; (ii) activation of p53 signaling cascade, including enhanced protein expressions of p16 and p21; (iii) downregulation of cyclin-dependent kinases, cyclin D1, cyclin A, cyclin E and proteins involved in cell division (e.g., Cdc25a and Cdc25b) leading to cell cycle arrest at S-phase; and (iv) mitochondrial membrane potential was disrupted and cytochrome c released. These changes in NMSCC by cryptolepine resulted in significant reduction in cell viability, colony formation and increase in apoptotic cell death.

miR-96 promotes cell proliferation, migration and invasion by targeting PTPN9 in breast cancer

microRNAs (miRNAs) have emerged as major regulators of the initiation and progression of human cancers, including breast cancer. The aim of this study is to determine the expression pattern of miR-96 in breast cancer and to investigate its biological role during tumorigenesis. We showed that miR-96 was significantly upregulated in breast cancer. We then investigated its function and found that miR-96 significantly promoted cell proliferation, migration and invasion in vitro and enhanced tumor growth in vivo. Furthermore, we explored the molecular mechanisms by which miR-96 contributes to breast cancer progression and identified PTPN9 (protein tyrosine phosphatase, non-receptor type 9) as a direct target gene of miR-96. Finally, we showed that PTPN9 had opposite effects to those of miR-96 on breast cancer cells, suggesting that miR-96 may promote breast tumorigenesis by silencing PTPN9. Taken together, this study highlights an important role for miR-96 in the regulation of PTPN9 in breast cancer cells and may provide insight into the molecular mechanisms of breast carcinogenesis.

MiR-181a-5p regulates 3T3-L1 cell adipogenesis by targeting Smad7 and Tcf7l2

MicroRNAs are highly conserved non-coding small RNAs participating in almost all kinds of biological activities. MiR-181a has been reported to be involved in the differentiation of porcine primary preadipocytes, but the profound effect of miR-181a-5p on 3T3-L1 adipocyte differentiation and proliferation is still unclear. In this study, we found that supplementation of miR-181a-5p in 3T3-L1 cells significantly promoted the adipogenesis and inhibited cell proliferation with increased expression of adipogenic marker genes including peroxisome proliferator-activated receptor gamma (Pparγ), CCAAT/enhancer-binding protein alpha (C/ebpα), fatty acid-binding protein 4 (Fabp4), and Adiponectin, accompanied by an accumulation of lipid droplet, an increase of triglyceride content, and a decrease of cell proliferation. Furthermore, by using the luciferase assay, Smad7 and Tcf7l2, two important members of transforming growth factor-β (TGFβ) and Wnt signaling pathway, were proven to be the direct target genes of miR-181a-5p. Moreover, supplementation of miR-181a-5p in 3T3-L1 cells altered the expressions of proteins involved in the TGFβ signaling pathway, such as TGFBR1, p-SMAD3, SMAD4, c-MYC, and p15. Taken together, these results indicate that miR-181a-5p promotes 3T3-L1 preadipocyte differentiation and adipogenesis through regulating TGFβ/Smad and Wnt signaling pathway by directly targeting Smad7 and Tcf7l2.

Suppression of iASPP-dependent aggressiveness in cervical cancer through reversal of methylation silencing of microRNA-124

Derepression of wild-type p53 by suppressing its negative inhibitor iASPP (Inhibitor of apoptosis-stimulating protein of p53) represents a potential therapeutic option for cervical cancer (CC). Here, we reported a novel functional significance of iASPP upregulation in cervical tumorigenesis: iASPP acts as a key promoter of CC cell proliferation, epithelial-mesenchymal transition, invasion and cancer stemness, by interacting with p53 to suppress p53-mediated transcription of target genes and reducing p53-responsive microRNA-34a levels. Moreover, we demonstrate that miR-124, directly targeting iASPP, reduces expression of iASPP and attenuates CC cell growth and invasiveness. Low miR-124 expression is inversely correlated with increased expression of iASPP mRNA in CC tissues. In a cohort of 40 patients with CC, the low miR-124 expression was correlated with poor 5-year overall survival (P = 0.0002) and shorter disease-free survival 5-year (P = 0006). Treatment with the DNA methyltransferase inhibitor Zebularine increases miR-124 expression and retards CC cell growth and invasion with minimal toxicity to normal cells. Even at a non-toxic concentration, Zebularine was effective in suppressing CC cell invasion and migration. Altogether, the restoration of miR-124 reduces iASPP expression and leads to p53-dependent tumor suppression, suggesting a therapeutic strategy to treat iASPP-associated CC.

Up-regulation of miR-95-3p in hepatocellular carcinoma promotes tumorigenesis by targeting p21 expression

Hepatocellular carcinoma (HCC) is one of the most common malignant cancers. To elucidate new regulatory mechanisms for heptocarcinogenesis, we investigated the regulation of p21, a cyclin-dependent kinase (CDK) inhibitor encoded by CDKN1A, in HCC. The expression level of p21 is decreased with the progression of HCC. Luciferase assays with a luciferase-p21-3' UTR reporter and its serial deletions identified a 15-bp repressor element at the 3'-UTR of CDKN1A, which contains a binding site for miR-95-3p. Mutation of the binding site eliminated the regulatory effect of miR-95-3p on p21 expression. Posttranscriptional regulation of p21 expression by miR-95-3p is mainly on the protein level (suppression of translation). Overexpression of miR-95-3p in two different HCC cell lines, HepG2 and SMMC7721, significantly promoted cell proliferation, cell cycle progression and cell migration, whereas a miR-95-3p specific inhibitor decreased cell proliferation, cell cycle progression and cell migration. The effects of miR-95-3p on cellular functions were rescued by overexpression of p21. Overexpression of miR-95-3p promoted cell proliferation and tumor growth in HCC xenograft mouse models. Expression of miR-95-3p was significantly higher in HCC samples than in adjacent non-cancerous samples. These results demonstrate that miR-95-3p is a potential new marker for HCC and regulates hepatocarcinogenesis by directly targeting CDKN1A/p21 expression.

miR-186 suppressed CYLD expression and promoted cell proliferation in human melanoma

Previous studies have shown that microRNA-186 (miR-186) is overexpressed in various human cancers and is associated with the regulation of the carcinogenic processes. However, the underlying mechanisms of this microRNA in melanoma remain largely unknown. In the present study, the overexpression of miR-186 was identified in melanoma tissues and melanoma cells compared to the expression of miR-186 in the matched tumor adjacent tissues and normal human epidermal melanocytes. Overexpression of miR-186 promoted the proliferation and anchorage-independent growth of melanoma cells, whereas inhibition of miR-186 reduced this effect. Bioinformatics analysis also revealed cylindromatosis (CYLD), a putative tumor suppressor, to be a potential target of miR-186. Luciferase reporter assays showed that miR-186 directly targeted the 3'-untranslated regions of CYLD messenger RNA. Additional experiments showed that overexpression of miR-186 promoted the proliferation of melanoma cells, which was consistent with the inhibitory effects induced by knockdown of CYLD. In summary, the present study indicated that miRNA-186 plays a crucial role in melanoma growth and its oncogenic effect is mediated chiefly through the direct suppression of CYLD expression.

MicroRNA-21a-5p Functions on the Regulation of Melanogenesis by Targeting Sox5 in Mouse Skin Melanocytes

MicroRNAs (miRNAs) play an important role in regulating almost all biological processes. miRNAs bind to the 3′ untranslated region (UTR) of mRNAs by sequence matching. In a previous study, we demonstrated that miR-21 was differently expressed in alpaca skin with different hair color. However, the molecular and cellular mechanisms for miR-21 to regulate the coat color are not yet completely understood. In this study, we transfected miR-21a-5p into mouse melanocytes and demonstrated its function on melanogenesis of miR-21a-5p by targeting Sox5, which inhibits melanogenesis in mouse melanocytes. The results suggested that miR-21a-5p targeted Sox5 gene based on the binding site in 3′ UTR of Sox5 and overexpression of miR-21a-5p significantly down-regulated Sox5 mRNA and protein expression. Meanwhile, mRNA and protein expression of microphthalmia transcription factor (MITF) and Tyrosinase (TYR) were up-regulated, which subsequently make the melanin production in melanocytes increased. The results suggest that miR-21a-5p regulates melanogenesis via MITF by targeting Sox5.

Therapeutic intervention of silymarin on the migration of non-small cell lung cancer cells is associated with the axis of multiple molecular targets including class 1 HDACs, ZEB1 expression, and restoration of miR-203 and E-cadherin expression

Lung cancer and its metastasis is the leading cause of cancer-related mortality world-wide. Non-small cell lung cancer (NSCLC) accounts for about 90% of total lung cancer cases. Despite advancements in therapeutic approaches, only limited improvement has been achieved. Therefore, alternative strategies are required for the management of lung cancer. Here we report the chemotherapeutic effect of silymarin, a phytochemical from milk thistle plant (Silybum marianum L. Gaertn.), on NSCLC cell migration using metastatic human NSCLC cell lines (A549, H1299 and H460) together with the molecular targets underlying these effects. Using an in vitro cell migration assay, we found that treatment of human NSCLC cells (A549, H1299 and H460) with silymarin (0, 5, 10 and 20 µg/mL) for 24 h resulted in concentration-dependent inhibition of cell migration, which was associated with the inhibition of histone deacetylase (HDAC) activity and reduced levels of class 1 HDAC proteins (HDAC1, HDAC2, HDAC3 and HDAC8) and concomitant increases in the levels of histone acetyltransferase activity (HAT). Known HDAC inhibitors (sodium butyrate and trichostatin A) exhibited similar patterns of therapeutic effects on the lung cancer cells. Treatment of A549 and H460 cells with silymarin reduced the expression of the transcription factor ZEB1 and restored expression of E-cadherin. The siRNA knockdown of ZEB1 also reduced the expression of HDAC proteins and enhanced re-expression of the levels of E-cadherin in NSCLC cells. MicroRNA-203 (miR-203) acts as a tumor suppressor, regulates tumor cell invasion and is repressed by ZEB1 in cancer cells. Silymarin treatment restored the levels of miR-203 in NSCLC cells. These findings indicate that silymarin can effectively inhibit lung cancer cell migration and provide a coherent model of its mechanism of action suggesting that silymarin may be an important therapeutic option for the prevention or treatment of lung cancer metastasis when administered either alone or with standard cancer therapeutic drugs.

Targeting MicroRNA in Cancer Using Plant-Based Proanthocyanidins

Proanthocyanidins are oligomeric flavonoids found in plant sources, most notably in apples, cinnamon, grape skin and cocoa beans. They have been also found in substantial amounts in cranberry, black currant, green tea, black tea and peanut skins. These compounds have been recently investigated for their health benefits. Proanthocyanidins have been demonstrated to have positive effects on various metabolic disorders such as inflammation, obesity, diabetes and insulin resistance. Another upcoming area of research that has gained widespread interest is microRNA (miRNA)-based anticancer therapies. MicroRNAs are short non-coding RNA segments, which plays a crucial role in RNA silencing and post-transcriptional regulation of gene expression. Currently, miRNA based anticancer therapies are being investigated either alone or in combination with current treatment methods. In this review, we summarize the current knowledge and investigate the potential of naturally occurring proanthocyanidins in modulating miRNA expression. We will also assess the strategies and challenges of using this approach as potential cancer therapeutics.

New Concepts in Cancer Biomarkers: Circulating miRNAs in Liquid Biopsies

The effective and efficient management of cancer patients relies upon early diagnosis and/or the monitoring of treatment, something that is often difficult to achieve using standard tissue biopsy techniques. Biological fluids such as blood hold great possibilities as a source of non-invasive cancer biomarkers that can act as surrogate markers to biopsy-based sampling. The non-invasive nature of these “liquid biopsies” ultimately means that cancer detection may be earlier and that the ability to monitor disease progression and/or treatment response represents a paradigm shift in the treatment of cancer patients. Below, we review one of the most promising classes of circulating cancer biomarkers: microRNAs (miRNAs). In particular, we will consider their history, the controversy surrounding their origin and biology, and, most importantly, the hurdles that remain to be overcome if they are really to become part of future clinical practice.

MicroRNA-106b is involved in transforming growth factor β1-induced cell migration by targeting disabled homolog 2 in cervical carcinoma

BACKGROUND

MicroRNA-106b (miR-106b) was recently identified as an oncogene participating in cancer progression. Transforming growth factor β1(TGF-β1) is an indispensable cytokine regulating the local microenvironment, thereby promoting cervical cancer progression. However, the roles of miR-106b in cervical carcinoma progression and TGF-β1-involvement in the tumorigenesis of cervical cancer remain unknown.

METHODS

The expression of miR-106b in human cervical specimens was detected by real-time PCR analysis and in situ hybridization assay. The effect of miR-106b on cell migration was analyzed by scratch and transwell assays. TGF-β1 was used to induce cell migration. The expression of the miR-106b target gene DAB2 in human cervical tissues and cell lines were measured by qRT-PCR, western blot and immunohistochemistry. Dual-luciferase reporter assay was used to identify DAB2 as a miR-106b-directed target gene.

RESULTS

miR-106b was frequently up-regulated in human cervical carcinoma specimens and cervical cancer cell lines. Over-expression of miR-106b significantly promoted HeLa and SiHa cells migration. Likewise, inhibition of miR-106b decreased HeLa and SiHa cells migration. The multifunctional cytokine TGF-β facilitates metastasis in cervical carcinoma. miR-106b inhibitor treatment decreased the TGF-β1-stimulated migration of HeLa and SiHa cells. DAB2, a predicted target gene of miR-106b, was inhibited by TGF-β1 partly through miR-106b and was involved in TGF-β1-induced cervical cancer cell migration. The expression of DAB2 was low in cervical cancer tissues, and negatively correlated with miR-106b expression. Finally, DAB2 was identified as a miR-106b-directed target gene by dual-luciferase reporter assay.

CONCLUSION

Our data suggest that the TGF-β1/miR-106b/DAB2 axis may be involved in the pathogenesis of cervical carcinoma.

miR-503 suppresses tumor cell proliferation and metastasis by directly targeting RNF31 in prostate cancer

Microarray data analyses were performed to search for metastasis-associated oncogenes in prostate cancer (PCa). RNF31 mRNA expressions in tumor tissues and benign prostate tissues were evaluated. The RNF31 protein expression levels were also analyzed by western blot and immunohistochemistry. Luciferase reporter assays were used to identify miRNAs that can regulate RNF31. The effect of RNF31 on PCa progression was studied in vitro and in vivo. We found that RNF31 was significantly increased in PCa and its expression level was highly correlated with seminal vesicle invasion, clinical stage, prostate specific antigen (PSA) level, Gleason score, and BCR. Silence of RNF31 suppressed PCa cell proliferation and metastasis in vitro and in vivo. miR-503 can directly regulate RNF31. Enforced expression of miR-503 inhibited the expression of RNF31 significantly and the restoration of RNF31 expression reversed the inhibitory effects of miR-503 on PCa cell proliferation and metastasis. These findings collectively indicated an oncogene role of RNF31 in PCa progression which can be regulated by miR-503, suggesting that RNF31 could serve as a potential prognostic biomarker and therapeutic target for PCa.

MicroRNA-495 downregulates FOXC1 expression to suppress cell growth and migration in endometrial cancer

MicroRNAs (miRNAs) are a class of noncoding RNAs and function as key regulators of gene expression at the post-transcriptional level. In this study, we found that miR-495 reduces cell growth, induces apoptosis and suppresses the migration of endometrial cancer by directly inhibiting FOXC1 expression. Further analysis revealed that FOXC1 promotes growth and migration and functions as an oncogene in vitro. FOXC1 overexpression reversed the cellular responses mediated by miR-495 in endometrial cancer cells. We also found that miR-495 suppresses the growth of endometrial cancer in vivo. Altogether, these results indicate that miR-495 acts as a tumour suppressor gene by targeting FOXC1 at the post-transcriptional level in endometrial cancer.

Antiproliferative Effect of Rottlerin on Sk-Mel-28 Melanoma Cells

Melanoma is the most aggressive and chemoresistant form of skin cancer. Mutated, constitutively active B-RAF is believed to play a crucial role, although the selective B-RAF inhibition has shown poor clinical success, since phenomena of resistance usually occur, likely arising from additional genetic aberrations, such as loss of function of p53 and PTEN, overexpression of cyclin D1, hyperactivation of NF-κB, and downregulation of p21/Cip1. Since all of them are present in the Sk-Mel-28 melanoma cells, this cell line could be an ideal, albeit hard to study, model to develop new therapeutic strategies. In the current study, we tested the cytostatic action of Rottlerin on Sk-Mel-28 melanoma cells, on the basis of the known Rottlerin effects on the main proliferative signaling pathways. We presented evidence that the drug inhibits cell growth by an Akt- and p21/Cip1-independent mechanism, involving the dual inhibition of ERK and NF-κB and downregulation of cyclin D1. In addition, we found that Rottlerin increases ERK phosphorylation, but, surprisingly, this resulted in decreased ERK activity. Pull-down experiments, using Rottlerin-CNBr-conjugated Sepharose beads, revealed that Rottlerin binds to ERK, independently from its phosphorylation status. This direct interaction could in part explain the paradoxical blockage of ERK downstream signaling and growth arrest.

We would like to dedicate this paper to the memory of our friend and colleague, prematurely deceased, Claudia Torricelli, who actively contributed to this project

MicroRNA-27a-3p Inhibits Melanogenesis in Mouse Skin Melanocytes by Targeting Wnt3a

MicroRNAs (miRNAs) play an essential role in the regulation of almost all the biological processes, including melanogenesis. MiR-27a-3p is nearly six times higher in white alpaca skin compared to brown skin, which indicates that miR-27a-3p may be a candidate regulator for melanogenesis. Wnt3a plays an important role in promoting melanoblasts to differentiate into melanocytes and melanogenesis. To confirm the function of miR-27a-3p to melanogenesis in mammals, miR-27a-3p mimic, inhibitor and their negative control were transfected into mouse melanocytes. As a result, miR-27a-3p inhibits melanogenesis by repressing Wnt3a at post-transcriptional level. A significant decrease in Wnt3a luciferase activity was observed in 293T cells co-transfected with the matched luciferase reporter vector and pre-miR-27a. Furthermore, the presence of exogenous miR-27a-3p significantly decreased Wnt3a protein expression rather than mRNA and reduced β-catenin mRNA levels in melanocytes. The over-expression of miR-27a-3p significantly increased the melanin content of melanocytes. However, miR-27a-3p inhibitor performs an opposite effect on melanogenesis. Wnt3a is one target of miR-27a-3p. MiR-27a-3p could inhibit Wnt3a protein amount by post-transcriptional regulation and melanogenesis in mouse melanocytes. Previous studies reported that Wnt3a promoted melanogenensis in mouse melanocytes. Thus, miR-27-3p inhibits melanogenesis by repressing Wnt3a protein expression.