Analyses in human urothelial cells identify methylation of miR-152, miR-200b and miR-10a genes as candidate bladder cancer biomarkers

Canine urothelial carcinoma: a pilot study of microRNA detection in formalin-fixed, paraffin-embedded tissue samples and in normal urine

We assessed the effects of fixation time in formalin and inclusion of surrounding tissue on microRNA (miRNA) cycle quantification (Cq) values in formalin-fixed, paraffin-embedded (FFPE) urothelial carcinoma (UC) tissue (n = 3), and the effect of conditions on miRNAs in urine from 1 healthy dog. MiRNAs were extracted using commercial kits and quantified using miRNA-specific fluorometry in normal bladder tissue scrolls, UC tissue cores, and bladder muscularis tissue cores from 4 FFPE bladder sections (3 UCs, 1 normal), plus 1 UC stored in formalin for 1, 8, 15, and 22 d before paraffin-embedding. Urine was collected from a healthy dog on 4 occasions; 1-mL aliquots were stored at 20, 4, -20, and -80°C for 4, 8, 24, and 48 h, and 1 and 2 wk. For both FFPE tissue and urine, we used reverse-transcription quantitative real-time PCR (RT-qPCR) to quantify miR-143, miR-152, miR-181a, miR-214, miR-1842, and RNU6B in each tissue or sample, using miR-39 as an exogenous control gene. The Cq values were compared with ANOVA and t-tests. The time of tissue-fixation in formalin did not alter miRNA Cq values; inclusion of the muscularis layer resulted in a statistically different miRNA Cq profile for miR-152, miR-181a, and RNU6B in bladder tissue. MiRNAs in acellular urine were stable for up to 2 wk regardless of the storage temperature. Our findings support using stored FFPE and urine samples for miRNA detection; we recommend measuring miRNA only in the tissue of interest in FFPE sections.

miRNAs as novel immunoregulators in cancer

The immune system is a well-known vital regulator of tumor growth, and one of the main hallmarks of cancer is evading the immune system. Immune system deregulation can lead to immune surveillance evasion, sustained cancer growth, proliferation, and metastasis. Tumor-mediated disruption of the immune system is accomplished by different mechanisms that involve extensive crosstalk with the immediate microenvironment, which includes endothelial cells, immune cells, and stromal cells, to create a favorable tumor niche that facilitates the development of cancer. The essential role of non-coding RNAs such as microRNAs (miRNAs) in the mechanism of cancer cell immune evasion has been highlighted in recent studies. miRNAs are small non-coding RNAs that regulate a wide range of post-transcriptional gene expression in a cell. Recent studies have focused on the function that miRNAs play in controlling the expression of target proteins linked to immune modulation. Studies show that miRNAs modulate the immune response in cancers by regulating the expression of different immune-modulatory molecules associated with immune effector cells, such as macrophages, dendritic cells, B-cells, and natural killer cells, as well as those present in tumor cells and the tumor microenvironment. This review explores the relationship between miRNAs, their altered patterns of expression in tumors, immune modulation, and the functional control of a wide range of immune cells, thereby offering detailed insights on the crosstalk of tumor-immune cells and their use as prognostic markers or therapeutic agents.

MicroRNA: A signature for cancer progression

MicroRNAs (miRNAs) are a group of small non-coding RNAs that post-transcriptionally control expression of genes by targeting mRNAs. miRNA alterations partake in the establishment and progression of different types of human cancer. Consequently, expression profiling of miRNA in human cancers has correlations with cancer detection, staging, progression, and response to therapies. Particularly, amplification, deletion, abnormal pattern of epigenetic factors and the transcriptional factors that mediate regulation of primary miRNA frequently change the landscape of miRNA expression in cancer. Indeed, changes in the quantity and quality of miRNAs are associated with the initiation of cancer, its progression and metastasis. Additionally, miRNA profiling has been used to categorize genes that can affect oncogenic pathways in cancer. Here, we discuss several circulating miRNA signatures, their expression profiles in different types of cancer and their impacts on cellular processes.

MicroRNA gga-miR-10a-mediated transcriptional regulation of the immune genes in necrotic enteritis afflicted chickens

miRNAs are involved in both adaptive and innate immune systems of host animals; and play important roles in many immune-related pathways. The systemic biological roles of gga-miR-10a-5p chicken microRNA on immune response were investigated in two necrotic enteritis (NE) induced chicken lines, Marek's disease (MD) resistant (line 6.3) and susceptible (line 7.2). We determined the expression patterns of gga-miR-10a in the intestinal mucosal layer of chickens upon NE induction, and identified the target genes (MyD88, and SKP1) related to the host immune response to pathogens. We found that gga-miR-10a expression in the intestinal mucosal layer of MD-resistant chicken line 6.3 gga-miR-10a was significantly down-regulated (p < 0.01) during NE. Overexpression analysis of gga-miR-10a and reporter gene analysis using a wild- or mutant-type MyD88 3' untranslated region (3' UTR)-luciferase construct in chicken macrophage cell line HD11 and chicken fibroblast cell line OU2 showed that gga-miR-10a acted as a direct translational repressor of MyD88 by targeting the 3' UTR of this gene. Furthermore, miR-10a indirectly negatively influenced the expression of signaling molecules related to the MyD88-dependent pathway, including TRAF6, TAK1, and NF-κB1 at both transcriptional and translational levels. Downstream of the MyD88-dependent pathway, several proinflammatory cytokines such as IL-1β, IFN-γ, IL-12p40, TNFSF15, and LITAF were down-regulated by overexpression of gga-miR-10a. These results suggest that gga-miR-10a is an important regulator of the Toll-like receptor signaling pathway. The findings of this study improve our understanding of the biological functions of miR-10a and the mechanisms underlying the TLR signaling pathway upon NE afflicted chickens, as well improving the overall understanding of the immune system function in domestic animals.

Mir-152 Regulates 3T3-L1 Preadipocyte Proliferation and Differentiation

Adipogenesis is a complex biological process and the main cause of obesity. Recently, microRNAs (miRNAs), a class of small endogenous non-coding RNAs, have been proven to play an important role in adipogenesis by the post-transcriptional regulation of target genes. In this current study, we observed an increment of miR-152 expression during the process of 3T3-L1 cell audiogenic differentiation. A functional analysis indicated that the overexpression of miR-152 inhibited pre-adipocyte proliferation and suppressed the expression of some cell cycle-related genes. Moreover, the overexpression of miR-152 promoted lipid accumulation in 3T3-L1 preadipocytes accompanied by increase of the expression of some pro-audiogenic genes. Additionally, a dual-luciferase reporter assay demonstrated lipoprotein lipase (LPL) was a direct target gene of miR-152 during preadipocyte differentiation. Further analysis showed that miR-152 was positively correlated with adipogenesis and intramuscular fat formation in vivo. Taken together, our findings suggest that miR-152 could suppress 3T3-L1 preadipocyte proliferation, whereas it could promote 3T3-L1 preadipocyte differentiation by negatively regulating LPL. The findings indicate that miR-152 might have a therapeutic significance for obesity and obesity-related metabolic syndrome.

MicroRNA‑214 upregulates HIF‑1α and VEGF by targeting ING4 in lung cancer cells

Previous reports have indicated a potential link between microRNA (miR)‑214 and hypoxia. In the present study, the biological functions and potential mechanisms of miR‑214 were determined, as well as its correlation with HIF‑1α signaling in non‑small cell lung cancer (NSCLC) cells. Quantitative polymerase chain reaction revealed that miR‑214 expression was upregulated in lung cancer tissues compared with adjacent normal tissues. miR‑214 mimics were transfected into A549 cells, and MTT, colony formation, invasion and wound healing assays were performed. It was demonstrated that miR‑214 mimic transfection promoted the invasion, proliferation and migration of A549 cells. Furthermore, miR‑214 inhibitor transfection decreased H1299 cell invasion, proliferation and migration. Next, the association between miR‑214 expression and the HIF‑1α signaling cascade was examined. It was demonstrated that miR‑214 mimics upregulated the expression of hypoxia‑inducible factor (HIF)‑1α, vascular endothelial growth factor (VEGF), adenylate kinase 3 and matrix metalloproteinase (MMP)2, whereas miR‑214 inhibitor downregulated the expression of these factors. Using prediction software, it was demonstrated that tumor suppressor ING4 was a target of miR‑214. A luciferase reporter assay confirmed that ING4 was a direct target of miR‑214. There was a negative correlation between ING4 and miR‑214 expression in lung cancer tissues. In addition, ING4 siRNA and plasmid was transfected into cells in order to validate its effect on HIF‑1α, MMP2 and VEGF expression. ING4 overexpression downregulated HIF‑1α and its targets MMP2 and VEGF, while ING4 siRNA upregulated HIF‑1α, MMP2 and VEGF. In conclusion, it was demonstrated that miR‑214 targeted ING4 in lung cancer cells, and upregulated the HIF‑1α cascade, leading to MMP2 and VEGF upregulation. This approach may help to clarify the role of miRNA in non‑small lung cancer and may be a new therapeutic target for non‑small lung cancer.

MicroRNA-98 promotes drug resistance and regulates mitochondrial dynamics by targeting LASS2 in bladder cancer cells

MicroRNA-98(miR-98) has been shown to be critical for tumorigenesis, however its involvement in bladder cancer are unclear. The present study aims to investigate the expression, biological roles and potential mechanisms of miR-98 in human bladder cancer. We found that miR-98 was upregulated in bladder urothelial carcinoma tissues compared with adjacent normal tissues. In addition, miR-98 expression was higher in bladder cancer cell lines than in uroepithelial cell line SV-HUC-1. Functional studies revealed that miR-98 mimic promoted proliferation of T24 cells while miR-98 inhibitor inhibited proliferation of BIU-87 cells. Moreover, miR-98 mimic increased cisplatin/doxorubicin resistance and inhibited apoptosis in T24 cells, while miR-98 inhibitor decreased chemoresistance and facilitated apoptosis in BIU-87 cells. Further experiments using MitoTracker and JC-1 staining showed that miR-98 could regulate mitochondrial fission/fusion balance and mitochondrial membrane potential. Western blot showed that miR-98 upregulated cyclin D1, p-Drp1 and Drp1. Using luciferase reporter assay, we demonstrated that LASS2 acted as a direct target of miR-98. LASS2 overexpression induced mitochondrial fusion and downregulated mitochondrial potential, with decreased p-Drp1 status. Additionally, LASS2 siRNA abrogated the effects of miR-98 mimic on Drp1phosphorylation and chemoresistance. We also found a negative correlation between LASS2 and miR-98 in bladder cancer tissues. In conclusion, our study demonstrates that miR-98 targets LASS2 and regulates bladder cancer chemoresistance through modulation of mitochondrial function.

Identifying a panel of genes/proteins/miRNAs modulated by arsenicals in bladder, prostate, kidney cancers

Arsenic and arsenic-derivative compounds, named as arsenicals, represent a worldwide problem for their effect on the human health and, in particular, for their capability to increase the risk of developing cancer such as kidney, bladder and prostate cancer. The main source of arsenical exposure is drinking water. Nowadays, it is well known that the chronic exposure to arsenicals leads to a series of epigenetic alterations that have a role in arsenic-induced effects on human health including cancer. Based on these observations, the aim of our study was to select by network analysis the genes/proteins/miRNAs implicated in kidney, bladder and prostate cancer development upon arsenical exposure. From this analysis we identified: (i) the nodes linking the three molecular networks specific for kidney, bladder and prostate cancer; (ii) the relative HUB nodes (RXRA, MAP3K7, NR3C1, PABPC1, NDRG1, RELA and CTNNB1) that link the three cancer networks; (iii) the miRNAs able to target these HUB nodes. In conclusion, we highlighted a panel of potential molecules related to the molecular mechanisms of arsenical-induced cancerogenesis and suggest their utility as biomarkers or therapeutic targets.

Involvement of methylation of MicroRNA-122, -125b and -106b in regulation of Cyclin G1, CAT-1 and STAT3 target genes in isoniazid-induced liver injury

Background

This investigation aimed to evaluate the role of methylation in the regulation of microRNA (miR)-122, miR-125b and miR-106b gene expression and the expression of their target genes during isoniazid (INH)-induced liver injury.

Methods

Rats were given INH 50 mg kg^− 1·d^− 1 once per day for 3, 7, 10, 14, 21 and 28 days and were sacrificed. Samples of blood and liver were obtained.

Results

We analysed the methylation and expression levels of miR-122, miR-125b and miR-106b and their potential gene targets in livers. Liver tissue pathologies, histological scores and alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities changed, indicating the occurrence of liver injury. Relative expression levels of miR-122, miR-125b and miR-106b genes in the liver decreased after INH administration and correlated with the scores of liver pathology and serum AST and ALT activities, suggesting that miR-122, miR-125b and miR-106b are associated with INH-induced liver injury. The amount of methylated miR-122, miR-125b and miR-106b in the liver increased after INH administration and correlated with their expression levels, suggesting the role of methylation in regulating miRNA gene expression. Two miR-122 gene targets, cell cycle protein G1 (Cyclin G1) and cationic amino acid transporter-1 (CAT-1), also increased at the mRNA and protein levels, which suggests that lower levels of miR-122 contribute to the upregulation of Cyclin G1 and CAT-1 and might play a role in INH-induced liver injury. Signal transducer and activator of transcription 3 (STAT3) was a common target gene of miR-125b and miR-106b, and its expression levels of mRNA and protein increased after INH administration. The protein expression of phosphorylated (p)-STAT3 and the mRNA expression of RAR-related orphan receptor gamma (RORγt) regulated by p-STAT3 also increased. Meanwhile, the mRNA and protein expression of interleukin (IL)-17 regulated by RORγt, and the mRNA and protein expression of CXCL1 and MIP-2 regulated by IL-17 increased after INH administration. These results demonstrate that lower levels of hepatic miR-125b and miR-106b contribute to the upregulation of STAT3 in stimulating the secretion of inflammatory factors during INH-induced liver injury.

Conclusions

Our results suggested that DNA methylation probably regulates the expression of miRNA genes (miR-122, miR-125b, and miR-106b), affecting the expression of their gene targets (Cyclin G1, CAT-1, and STAT3) and participating in the process of INH-induced liver injury.

Electronic supplementary material

The online version of this article (10.1186/s40360-018-0201-x) contains supplementary material, which is available to authorized users.

Dysregulation of miRNAs in bladder cancer: altered expression with aberrant biogenesis procedure

Aberrant expression profiles of miRNAs are widely observed in the clinical tissue specimens and urine samples as well as the blood samples of bladder cancer patients. These profiles are closely related to the pathological features of bladder cancer, such as the tumour stage/grade, metastasis, recurrence and chemo-sensitivity. MiRNA biogenesis forms the basis of miRNA expression and function, and its dysregulation has been shown to be essential for variations in miRNA expression profiles as well as tumourigenesis and cancer progression. In this review, we summarize the up-to-date and widely reported miRNAs in bladder cancer that display significantly altered expression. We then compare the miRNA expression profiles among three different sample types (tissue, urine and blood) from patients with bladder cancer. Moreover, for the first time, we outline the dysregulated miRNA biogenesis network in bladder cancer from different levels and analyse its possible relationship with aberrant miRNA expression and the pathological characteristics of the disease.

Epigenetics and MicroRNAs in Cancer

The ability to reprogram the transcriptional circuitry by remodeling the three-dimensional structure of the genome is exploited by cancer cells to promote tumorigenesis. This reprogramming occurs because of hereditable chromatin chemical modifications and the consequent formation of RNA-protein-DNA complexes that represent the principal actors of the epigenetic phenomena. In this regard, the deregulation of a transcribed non-coding RNA may be both cause and consequence of a cancer-related epigenetic alteration. This review summarizes recent findings that implicate microRNAs in the aberrant epigenetic regulation of cancer cells.

miR‑214 reduces cisplatin resistance by targeting netrin‑1 in bladder cancer cells

miR‑214 has been reported to be downregulated in several cancer types, such as bladder cancer. However, its involvement in apoptosis and chemoresistance has not been investigated. The present study aimed to clarify the biological function of miR‑214 and potential mechanisms in chemoresistance of bladder cancer cells. Reverse transcription‑quantitative polymerase chain reaction demonstrated that miR‑214 was downregulated in bladder cancer tissues compared with the level in normal tissues. miR‑214 was downregulated in bladder cancer cell lines compared with the level in the normal cell line SV‑HUC‑1. miR‑214 mimics were transfected into T24 and J82 cell lines to restore its expression. The results indicated that miR‑214 mimic inhibited proliferation and invasion in these cell lines. In addition, miR‑214 mimic reduced cisplatin resistance in T24 and J82 cells, indicated by the inhibition of cell viability and upregulation of cell apoptosis. Western blotting demonstrated that miR‑214 mimic was able to upregulate cleaved caspase‑3 and cleaved poly (ADP‑ribose) polymerase (PARP), while downregulate caspase‑3 and PARP expression, and AKT phosphorylation. Using prediction software, it was revealed that the netrin‑1 oncoprotein is on the target list of miR‑214. miR‑214 also downregulated netrin‑1 protein and mRNA expression levels in the T24 and J82 cell lines. Luciferase reporter assays demonstrated that netrin‑1 acted as a direct target of miR‑214. A negative correlation between netrin‑1 and miR‑214 expression in bladder cancer tissues was also observed. In addition, cisplatin treatment could induce netrin‑1 protein expression in bladder cancer cells and miR‑214 mimic partly blocked this phenomenon. Netrin‑1 plasmid transfection inhibited cisplatin‑induced apoptosis, upregulated AKT phosphorylation, and downregulated caspase‑3 and PARP cleavage. Netrin‑1 was restored in cells transfected with miR‑214 mimic using plasmid transfection. Netrin‑1 transfection restored AKT phosphorylation and blocked caspase/PARP cleavage in the T24 and J82 cell lines. In conclusion, the present study demonstrated that miR‑214 is downregulated in bladder cancer tissues and cell lines. miR‑214 reduces chemoresistance by targeting netrin‑1 in bladder cancer cell lines.

Clinical significance of miRNA host gene promoter methylation in prostate cancer

Only a part of prostate cancer (PCa) patients has aggressive malignancy requiring adjuvant treatment after radical prostatectomy (RP). Biomarkers capable to predict biochemical PCa recurrence (BCR) after RP would significantly improve preoperative risk stratification and treatment decisions. MicroRNA (miRNA) deregulation has recently emerged as an important phenomenon in tumor development and progression, however, the mechanisms remain largely unstudied. In the present study, based on microarray profiling of DNA methylation in 9 pairs of PCa and noncancerous prostate tissues (NPT), host genes of miR-155-5p, miR-152-3p, miR-137, miR-31-5p, and miR-642a, -b were analyzed for promoter methylation in 129 PCa, 35 NPT, and 17 benign prostatic hyperplasia samples (BPH) and compared to the expression of mature miRNAs and their selected targets (DNMT1, KDM1A, and KDM5B). The Cancer Genome Atlas dataset was utilized for validation. Methylation of mir-155, mir-152, and mir-137 host genes was PCa-specific, and downregulation of miR-155-5p significantly correlated with promoter methylation. Higher KDM5B expression was observed in samples with methylated mir-155 or mir-137 promoters, whereas upregulation of KDM1A and DNMT1 was associated with mir-155 and mir-152 methylation status, respectively. Promoter methylation of mir-155, mir-152, and mir-31 was predictive of BCR-free survival in various Cox models and increased the prognostic value of clinicopathologic factors. In conclusion, methylated mir-155, mir-152, mir-137, and mir-31 host genes are promising diagnostic and/or prognostic biomarkers of PCa. Methylation status of particular miRNA host genes as independent variables or in combinations might assist physicians in identifying poor prognosis PCa patients preoperatively.

Immune Modulatory microRNAs Involved in Tumor Attack and Tumor Immune Escape

Current therapies against cancer utilize the patient's immune system for tumor eradication. However, tumor cells can evade immune surveillance of CD8+ T and/or natural killer (NK) cells by various strategies. These include the aberrant expression of human leukocyte antigen (HLA) class I antigens, co-inhibitory or costimulatory molecules, and components of the interferon (IFN) signal transduction pathway. In addition, alterations of the tumor microenvironment could interfere with efficient antitumor immune responses by downregulating or inhibiting the frequency and/or functional activity of immune effector cells and professional antigen-presenting cells. Recently, microRNAs (miRNAs) have been identified as major players in the post-transcriptional regulation of gene expression, thereby controlling many physiological and also pathophysiological processes including neoplastic transformation. Indeed, the cellular miRNA expression pattern is frequently altered in many tumors of distinct origin, demonstrating the tumor suppressive or oncogenic potential of miRNAs. Furthermore, there is increasing evidence that miRNAs could also influence antitumor immune responses by affecting the expression of immune modulatory molecules in tumor and immune cells. Apart from their important role in tumor immune escape and altered tumor-host interaction, immune modulatory miRNAs often exert neoplastic properties, thus representing promising targets for future combined immunotherapy approaches. This review focuses on the characterization of miRNAs involved in the regulation of immune surveillance or immune escape of tumors and their potential use as diagnostic and prognostic biomarkers or as therapeutic targets.

MicroRNAs in Different Histologies of Soft Tissue Sarcoma: A Comprehensive Review

Soft tissue sarcomas (STS) constitute a rare tumour entity comprising over 50 histological subtypes. MicroRNAs (miRNAs) are short non-protein coding RNA molecules that regulate gene expression by targeting the 3'-untranslated region of messenger RNAs. They are involved in a variety of human diseases, including malignancies, such as endometrial cancer, osteosarcoma, bronchial carcinoma and breast cancer. In STS, various miRNAs are differentially expressed, thus contributing to development, progression and invasion. Therefore, the aim of the present review is to summarise current knowledge on the role of miRNAs in STS. Furthermore, the potential role of miRNAs as diagnostic, prognostic and predictive biomarkers is discussed.

Chromatin immunoprecipitation in microfluidic droplets: towards fast and cheap analyses

Genetic organization is governed by the interaction of DNA with histone proteins, and differential modifications of these proteins is a fundamental mechanism of gene regulation. Histone modifications are primarily studied through chromatin immunoprecipitation (ChIP) assays, however conventional ChIP procedures are time consuming, laborious and require a large number of cells. Here we report for the first time the development of ChIP in droplets based on a microfluidic platform combining nanoliter droplets, magnetic beads (MB) and magnetic tweezers (MT). The droplet approach enabled compartmentalization and improved mixing, while reducing the consumption of samples and reagents in an integrated workflow. Anti-histone antibodies grafted to MB were used as a solid support to capture and transfer the target chromatin from droplets to droplets in order to perform chromatin immunoprecipitation, washing, elution and purification of DNA. We designed a new ChIP protocol to investigate four different types of modified histones with known roles in gene activation or repression. We evaluated the performances of this new ChIP in droplet assay in comparison with conventional methods. The proposed technology dramatically reduces analytical time from a few days to 7 hours, simplifies the ChIP protocol and decreases the number of cells required by 100 fold while maintaining a high degree of sensitivity and specificity. Therefore this droplet-based ChIP assay represents a new, highly advantageous and convenient approach to epigenetic analyses.

miR-152 down-regulation is associated with MET up-regulation in leiomyosarcoma and undifferentiated pleomorphic sarcoma

PURPOSE

Highly aggressive adult soft tissue sarcomas (STS), i.e., leiomyosarcomas (LMS) and undifferentiated pleomorphic sarcomas (UPS), present complex genomic anomalies and overall 5-year survival rates of 20 to 40%. Here, we aimed to identify new biomarkers that may be employed to improve the treatment of non-translocation STS patients. We validated 12 miRNAs implicated in tumor development using primary STS samples and selected miR-152 for further analysis in STS-derived cell lines.

METHODS

59 primary STS samples (27 LMS and 32 UPS) and 10 matched normal control tissues were included in the study, as well as 3 STS-derived cell lines (HT1080, SW872 and SKLMS1) and a normal control mesenchymal cell line (hMSC). miRNA expression analyses were performed using a TaqMan microRNA Array platform and qRT-PCR (miR-152), respectively. The expression levels of the putative miR-152 targets MET and KIT were assessed using qRT-PCR and immunohistochemistry on tissue microarrays, respectively. In addition, various functional analyses were performed before and after miR-152 transfection into SKLMS1 cells.

RESULTS

We found that 12 pre-selected miRNAs were down-regulated in primary STS tumor samples compared to its normal control samples. A statistically significant miR-152 down-regulation was found to be accompanied by high MET and KIT mRNA levels in both the primary samples and the STS-derived cell lines tested. miR-152 transfection in SKLMS1 cells led to a reduction in KIT and MET mRNA and protein levels which, in turn, was associated with a transient down-regulation of the PI3K/AKT pathway, a transient decrease in cell growth, and a transient increase in both apoptotic and S-phase cells.

CONCLUSIONS

Our data indicate that over-expression of MET and KIT in primary STS samples and its derived cell lines is associated with miR-152 down-regulation. This shift may play a role in STS development and, thus, may be used to identify patients at risk. The effect of MET down-regulation on downstream signaling pathways, such as the PI3K/AKT pathway, may provide a basis for the future design of novel STS treatment strategies.

MicroRNA-200b acts as a tumor suppressor in osteosarcoma via targeting ZEB1

Osteosarcoma is the most common type of cancer that develops in bone, mainly arising from the metaphysis of the long bones. MicroRNA (miR)-200b has been found to generally act as a tumor suppressor in multiple types of human cancers. However, the detailed role of miR-200b in osteosarcoma still remains to be fully understood. This study aimed to investigate the exact role of miR-200b in the progression of osteosarcoma and the underlying mechanism. Real-time reverse transcription-polymerase chain reaction data showed that miR-200b was significantly downregulated in osteosarcoma tissues compared to their matched adjacent nontumor tissues. Low miR-200b level was associated with the advanced clinical stage and positive distant metastasis. Besides, it was also downregulated in osteosarcoma cell lines (U2OS, Saos2, HOS, and MG63) compared to normal osteoblast cell line NHOst. In vitro study showed that restoration of miR-200b led to a significant decrease in proliferation, migration, and invasion of osteosarcoma cells. Moreover, ZEB1 was identified as a target gene of miR-200b, and its expression levels were negatively mediated by miR-200b in osteosarcoma cells. In addition, ZEB1 was significantly upregulated in osteosarcoma cells compared to the normal osteoblast cell line NHOst, and inhibition of ZEB1 expression also suppressed the proliferation, migration, and invasion in osteosarcoma cells. Finally, we showed that ZEB1 was frequently upregulated in osteosarcoma tissues compared to their matched adjacent normal tissues, and its expression was reversely correlated to the miR-200b levels in osteosarcoma tissues. Based on these findings, our study suggests that miR-200b inhibits the proliferation, migration, and invasion of osteosarcoma cells, probably via the inhibition of ZEB1 expression. Therefore, miR-200b/ZEB1 may become a potential target for the treatment of osteosarcoma.

Biomarkers for non-muscle invasive bladder cancer: Current tests and future promise

The search continues for optimal markers that can be utilized to improve bladder cancer detection and to predict disease recurrence. Although no single marker has yet replaced the need to perform cystoscopy and urine cytology, many tests have been evaluated and are being developed. In the future, these promising markers may be incorporated into standard practice to address the challenge of screening in addition to long-term surveillance of patients who have or are at risk for developing bladder cancer.

microRNA deregulation in keloids: an opportunity for clinical intervention?

Keloids are defined as benign dermal scars invading adjacent healthy tissue, characterized by aberrant fibroblast dynamics and overproduction of extracellular matrix. However, the aetiology and molecular mechanism of keloid production remain poorly understood. Recent discoveries have shed new light on the involvement of a class of non-coding RNAs known as microRNAs (miRNA), in keloid formation. A number of miRNAs have differential expression in keloid tissues and keloid-derived fibroblasts. These miRNAs have been characterized as novel regulators of cellular processes pertinent to wound healing, including extracellular matrix deposition and fibroblast proliferation. Delineating the functional significance of miRNA deregulation may help us better understand pathogenesis of keloids, and promote development of miRNA-directed therapeutics against this condition.

Effects of miR-152 on cell growth inhibition, motility suppression and apoptosis induction in hepatocellular carcinoma cells

BACKGROUND

miR-152 is involved in the genesis and development of several malignancies. However, its role in HCC has not been fully clarified. The aim of this study was to investigate the clinicopathological significance of miR-152 and its effect on the malignant phenotype of HCC cells.

METHODS

miR-152 expression was detected using real-time quantitative RT-PCR in 89 pairs of HCC formalin-fixed paraffin-embedded and their adjacent tissues. Functionally, in vitro effects and mechanisms of action of miR-152 on proliferation, viability, caspase activity, apoptosis and motility were explored in HepG2, HepB3 and SNU449 cells, as assessed by spectrophotometry, fluorimetry, fluorescence microscopy, wound-healing and Western blotting, respectively.

RESULTS

miR-152 expression in HCC was downregulated remarkably compared to that in adjacent hepatic tissues. miR-152 levels in groups of advanced clinical stage, larger tumor size and positive HBV infection, were significantly lower than in other groups. A miR-152 mimic could suppress cell growth, inhibit cell motility and increase caspase activity and apoptosis in HCC cell lines. Furthermore, Western blotting showed that the miR-152 mimic downregulated Wnt-1, DNMT1, ERK1/2, AKT and TNFRS6B signaling. Intriguingly, inverse correlation of TNFRF6B and miR-152 expression was found in HCC and bioinformatics confirmed that TNFRF6B might be a target of miR- 152.

CONCLUSIONS

Underexpression of miR-152 plays a vital role in hepatocarcinogenesis and lack of miR-152 is related to the progression of HCC through deregulation of cell proliferation, motility and apoptosis. miR-152 may act as a tumor suppressor miRNA by also targeting TNFRSF6B and is therefore a potential candidate biomarker for HCC diagnosis, prognosis and molecular therapy.

MicroRNA-10a silencing reverses cisplatin resistance in the A549/cisplatin human lung cancer cell line via the transforming growth factor-β/Smad2/STAT3/STAT5 pathway

Lung cancer is one of the primary causes of mortality worldwide and drug resistance is the key contributing factor which results in the failure of lung cancer chemotherapy. Previous studies have shown that microRNA (miR)‑10a was involved in the reversal of cisplatin (DDP) resistance in numerous types of tumors; however, the underlying mechanism of action of this remains to be fully elucidated. In the present study, miR‑10a silencing in human DDP‑resistant lung cancer A549/DDP cells was demonstrated to improve DDP sensitivity, apoptosis, intracellular rhodamine‑123 content as well as the expression and activity of caspase‑3/8. In addition, miR‑10a suppressed the cellular expression of P‑glycoprotein, multi‑drug resistance protein (MDR) 1, MDR‑associated protein 1, RhoE, B cell lymphoma‑2 and survivin in A549/DDP cells. Furthermore, miR‑10a silencing inhibited the secretion of transforming growth factor (TGF)‑β, phosphorylation of Sma‑ and Mad‑related protein (Smad)2, signal transducer and activator of transcription (STAT)3 and STAT5, the transcriptional activity of hypoxia‑inducible factor and eukaryotic translation initiation factor 4E in human lung cancer A549/DDP cell line. These results therefore indicated that miR‑10a may be a potential target for improving the effectiveness of lung cancer chemotherapy via regulation of the TGF‑β/Smad2/STAT3/STAT5 pathway.

Expression and clinical significance of microRNA-152 in supragalottic laryngeal carcinoma

MicroRNAs (miRNAs) are small, noncoding RNAs of endogenous origin that play an important role in tumor development. Here, we examined the role of miR-152 in supragalottic laryngeal carcinoma. The expression of miR-152 was assessed by real-time PCR in tissues from 83 patients with supragalottic laryngeal carcinoma in relation to clinicopathological parameters. Cell viability was assessed by thiazolyl blue assay in Hep-2 cells transfected with miR-152 mimics or a negative control. MiR-152 was significantly downregulated in supragalottic laryngeal carcinoma tissues (t = 12.65, p < 0.001, paired t test), and its expression was correlated with pT stage (χ(2) = 26.88, p < 0.001) and pN stage (z = -3.56, p < 0.001) in patients with supragalottic laryngeal carcinoma. MiR-152 inhibited the proliferation of Hep-2 cells. MiR-152 may serve as a novel prognostic marker in patients with supragalottic laryngeal carcinoma.

Human papilloma virus, DNA methylation and microRNA expression in cervical cancer (Review)

Cancer is a complex disease caused by genetic and epigenetic abnormalities that affect gene expression. The progression from precursor lesions to invasive cervical cancer is influenced by persistent human papilloma virus (HPV) infection, which induces changes in the host genome and epigenome. Epigenetic alterations, such as aberrant miRNA expression and changes in DNA methylation status, favor the expression of oncogenes and the silencing of tumor-suppressor genes. Given that some miRNA genes can be regulated through epigenetic mechanisms, it has been proposed that alterations in the methylation status of miRNA promoters could be the driving mechanism behind their aberrant expression in cervical cancer. For these reasons, we assessed the relationship among HPV infection, cellular DNA methylation and miRNA expression. We conclude that alterations in the methylation status of protein-coding genes and various miRNA genes are influenced by HPV infection, the viral genotype, the physical state of the viral DNA, and viral oncogenic risk. Furthermore, HPV induces deregulation of miRNA expression, particularly at loci near fragile sites. This deregulation occurs through the E6 and E7 proteins, which target miRNA transcription factors such as p53.

MicroRNA-10a controls airway smooth muscle cell proliferation via direct targeting of the PI3 kinase pathway

Airway smooth muscle (ASM) cells play important physiological roles in the lung, and abnormal proliferation of ASM directly contributes to the airway remodeling during development of lung diseases such as asthma. MicroRNAs are small yet versatile gene tuners that regulate a variety of cellular processes, including cell growth and proliferation; however, little is known about the precise role of microRNAs in the proliferation of the ASM. Here we report that a specific microRNA (miR-10a) controls ASM proliferation through directly inhibiting the phosphoinositide 3-kinase (PI3K) pathway. Next-generation sequencing identified miR-10a as the most abundant microRNA expressed in primary human airway smooth muscle (HASM) cells, accounting for > 20% of all small RNA reads. Overexpression of miR-10a reduced mitogen-induced HASM proliferation by ∼50%, whereas inhibition of miR-10a increased HASM proliferation by ∼40%. Microarray profiling of HASM cells expressing miR-10a mimics identified 52 significantly down-regulated genes as potential targets of miR-10a, including the catalytic subunit α of PI3K (PIK3CA), the central component of the PI3K pathway. MiR-10a directly suppresses PIK3CA expression by targeting the 3'-untranslated region (3'-UTR) of the gene. Inhibition of PIK3CA by miR-10a reduced V-akt murine thymoma viral oncogene homolog 1 (AKT) phosphorylation and blunted the expression of cyclins and cyclin-dependent kinases that are required for HASM proliferation. Together, our study identifies a novel microRNA-mediated regulatory mechanism for PI3K signaling and ASM proliferation and further suggests miR-10a as a potential therapeutic target for lung diseases whose etiology resides in abnormal ASM proliferation.

miR-200b suppresses cell proliferation, migration and enhances chemosensitivity in prostate cancer by regulating Bmi-1

microRNAs (miRNAs) are a class of small non-coding RNAs that can post-transcriptionally regulate gene expression and play critical roles in many important biological processes. The role of miRNAs in prostate cancer (PCa) development and pathogenesis remains largely unknown. In the present study, we showed that miR-200b was downregulated in clinical prostatic tumors when compared to normal prostate tissue and in advanced PCa cell lines when compared to normal epithelial prostatic cells. Enforced miR-200b expression suppressed PCa cell proliferation and migration and enhanced chemosensitivity to docetaxel by targeting B-cell-specific Moloney murine leukemia virus insertion site 1 (Bmi-1). Bmi-1 was detected at higher levels in PCa, and knockdown of Bmi-1 showed similar effects as miR-200b overexpression in PCa cells. Moreover, we confirmed that these effects were correlated with increased levels of E-cadherin and P16 and a reduction in vimentin expression and expression of stem cell markers (CD44 and OCT4). These findings suggest that miR-200b plays vital roles as a tumor-suppressor by targeting Bmi-1 and may be a promising therapeutic target for PCa treatment.