microRNA-199a-3p,DNMT3A,and aberrant DNA methylation in testicular cancer

It was previously demonstrated that miR-199a was downregulated in testicular germ cell tumor (TGCT), probably due to hypermethylation of its promoter. Further study found that re-expression of miR-199a in testicular cancer cells (NT2) led to suppression of cell growth, cancer migration, invasion and metastasis. More detailed analyses showed that these properties of miR-199a could be assigned to miR-199a-5p, one of its two derivatives. The biological role of the other derivative, miR-199a-3p in TGCT, remains largely uncharacterized. In this report, we identified DNA (cytosine-5)-methyltransferase 3A (DNMT3A), the de novo methyltransferase, as a direct target of miR-199a-3p using a 3′-UTR reporter assay. Transient expression of miR-199a-3p in NT2 cells led to decrease, while knocking down of miR-199a-3p in a normal human testicular cell line (HT) led to elevation, of DNMT3A2 (DNMT3A gene isoform 2) mRNA and protein levels. In clinical samples, DNMT3A2 was significantly overexpressed in malignant testicular tumor, and the expression of DNMT3A2 was inversely correlated with the expression of miR-199a-3p. However, DNMT3A did not affect miR-199a expression in NT2 cells. Further characterization of miR-199a-3p revealed that it negatively regulated DNA methylation, partly through targeting DNMT3A. Overexpression of miR-199a-3p restored the expression of APC and MGMT tumor-suppressor genes in NT2 cells by affecting DNA methylation of their promoter regions. Our studies demonstrated the deregulation of miR-199a-3p expression in TGCT may provide novel mechanistic insights into TGCT carcinogenesis and suggested a potentially therapeutic use of synthetic miR-199a-3p oligonucleotides as effective hypomethylating compounds in the treatment of TGCT.     

Downregulation of microRNA-92b-3p suppresses proliferation,migration, and invasion of gastric cancer SGC-7901 cells by targeting Homeobox D10

To investigate the effect and mechanism of microRNA-92b-3p (miR-92b-3p) targeting Homeobox D10 (HOXD10) on proliferation, migration, and invasion of gastric cancer, we detected t he expression of miR-92b-3p and HOXD10 in SGC-7901 cells. The effects of miR-92b-3p or HOXD10 on proliferation, migration, invasion, and matrix metalloproteinase (MMP)-2/9 expression in SGC-7901 cells were measured by the Cell Counting Kit-8 assay, Transwell assay, and Western blot, respectively. The results showed that miR-92b-3p expression was increased, and HOXD10 expression was decreased in SGC-7901 cells, compared with human normal gastric epithelial cells GES-1. Functional experiments demonstrated that cell proliferation, migration, invasion, and expression of MMP-2/9 in SGC-7901 cells were significantly inhibited by miR-92b-3p silencing and HOXD10 overexpression. Moreover, HOXD10 was a potential target gene of miR-92b-3p as evidenced by the TargetScan software and double luciferase reporter assay. In the rescue experiment, knockdown of HOXD10, accompanied by higher expression of MMP-2/9, could significantly eliminate the inhibitory effects of miR-92b-3p silencing on cell proliferation, migration, and invasion. In conclusion, miR-92b-3p is highly expressed in gastric cancer SGC-7901 cells, and interfering with its expression might inhibit SGC-7901 cell proliferation, migration, and invasion via downregulating MMP-2/9 expression and targeting HOXD10.     

环状RNA circMRPS35通过miR-130a-3p/ZNRF3轴调节胃癌细胞的增殖、凋亡、迁移和侵袭

摘要 目的：探讨环状RNA MRPS35（circMRPS35）对胃癌（GC）细胞增殖、凋亡、迁移和侵袭的调控机制。方法：体外培养人GC细胞系（HGC-27、MGC-803、MKN45和AGS）和正常胃上皮GES-1细胞,实时荧光定量PCR（RT-qPCR）检测circMRPS35、miR-130a-3p和锌环指蛋白3（ZNRF3）mRNA表达。另取MGC-803细胞,分为对照组、pc-NC组、pc-circMRPS35组、pc-circMRPS35+miR-NC组、pc-circMRPS35+miR-130a-3p组,采用Lipofectamine 3000进行质粒转染。RT-qPCR检测circMRPS35、miR-130a-3p和ZNRF3 mRNA表达,Western blot检测ZNRF3蛋白表达,CCK-8法、流式细胞术检测细胞增殖与凋亡,划痕实验和Transwell小室实验检测细胞迁移与侵袭能力,裸鼠移植瘤实验探究circMRPS35对GC细胞体内生长的影响。双荧光素酶报告基因检测miR-130a-3p与circMRPS35或ZNRF3的靶标关系。结果：GC细胞系中circMRPS35和ZNRF3 mRNA呈低表达,miR-130a-3p呈高表达（均P＜0.05）。过表达circMRPS35可降低miR-130a-3p,上调ZNRF3 mRNA和蛋白水平,抑制细胞增殖、迁移和侵袭,并促进细胞凋亡（均P＜0.05）;circMRPS35过表达对GC细胞恶性行为和裸鼠移植瘤生长的抑制作用可被miR-130a-3p mimic逆转（P＜0.05）。双荧光素酶实验结果显示,过表达miR-130a-3p可降低circMRPS35-WT和ZNRF3-WT的荧光素酶活性（P＜0.05）。结论：circMRPS35可能通过miR-130a-3p/ZNRF3轴抑制GC细胞的增殖、迁移和侵袭,并促进细胞凋亡。     

MiR-517a-3p accelerates lung cancer cell proliferation and invasion through inhibiting FOXJ3 expression

Aims

Aberrant expression of microRNAs (miRNAs) results in alterations of various biological processes (e.g., cell cycle, cell differentiation, and apoptosis) and cell transformation. Altered miRNAs expression was associated with lung carcinogenesis and tumor progression. This study aimed to investigate the function and underlying molecular events of miR-517a-3p on regulation of lung cancer cell proliferation and invasion.

Main methods

Transfected miR-517a-3p mimics or inhibitors into 95D and 95C cells respectively, the effects of miR-517a-3p on lung cancer cell proliferation, migration, and invasion were detected. Bioinformatics software forecasted potential target genes of miR-517a-3p and dual luciferase reporter gene system and western blot verified whether miR-517a-3p regulates FOXJ3 expression directly.

Key findings

MiR-517a-3p was differentially expressed in lung cancer 95D and 95C cell lines that have different metastatic potential. Manipulation of miR-517a-3p expression changed lung cancer cell proliferation, migration and invasion capacity. MiR-517a-3p directly regulated FOXJ3 expression by binding to FOXJ3 promoter.

Significance

This study demonstrated that miR-517a-3p promoted lung cancer cell proliferation and invasion by targeting of FOXJ3 expression.     

MicroRNA-487a-3p functions as a new tumor suppressor in prostate cancer by targeting CCND1

Prostate cancer (PCa) is one of the major health problems of the aging male. The roles of dysregulated microRNAs in PCa remain unclear. In this study, we mined the public published data and found that miR-487a-3p was significantly downregulated in 38 pairs of clinical prostate tumor tissues compared with the normal tissues. We further verified this result by in situ hybridization on tissue chip and quantitative real-time polymerase chain reaction (qRT-PCR) in PCa/normal cells. miR-487a-3p targeting of cyclin D1 (CCND1) was identified using bioinformatics, qRT-PCR and western blot analyses. The cellular proliferation, cell cycle, migration, and invasion were assessed by cell counting kit-8, flow cytometry analysis and transwell assay. We discovered that overexpression of miR-487a-3p suppressed PCa cell growth, migration, invasion by directly targeting CCND1. Knockdown of CCND1 in PCa cells showed similar results. Meanwhile, the expression level of CCND1 was significantly upregulated in the PCa tissues and cell lines, which presented negative correlation with the expression of miR-487a-3p. More important, we demonstrated significantly reduced growth of xenograft tumors of stable miR-487a-3p-overexpressed human PCa cells in nude mice. Taken together, for the first time, our results revealed that miR-487a-3p as a tumor suppressor of PCa could target CCND1. Our finding might reveal miR-487a-3p could be potentially contributed to the pathogenesis and a clinical biomarker or the new potential therapeutic target of PCa.     

MiR-125a-3p Regulates Glioma Apoptosis and Invasion by Regulating Nrg1

The current study was designed to examine the functional role and mechanism of miR-125a-3p in glioma development. Quantitative RT-PCR was used to evaluate miR-125a-3p expression in 60 glioma cases of different malignant grades. Then, the clinic pathologic significance of miR-125a-3p expression was determined in combination with the prognosis of the patients. In addition, the effects and mechanisms of miR-125a-3p on the proliferation, apoptosis and invasion of glioma cells were further investigated. The results showed that the expression of miR-125a-3p was decreased significantly in most malignant glioma samples relative to normal brain tissues and glioma tissues of low-malignant degree. Further kaplan-meier survival analysis showed that the lower expression of miR-125a-3p was associated with a poor prognosis of GBM patients. Functional analysis showed that the reintroduction of miR-125a-3p into glioblastoma cell lines induces markedly the apoptosis and suppresses the proliferation and migration of glioblastoma cells in vitro and in vivo. Luciferase assay and Western blot analysis revealed that Nrg1 is a direct target of miR-125a-3p. Furthermore, an increased expression of Nrg1 could reverse the effects of overexpression of miR-125a-3p on the proliferation, apoptosis and migration of glioblastoma cells. These findings suggest that miR-125a-3p performed an important role in glioma development mediated by directly regulating the expression of Nrg1. This study also provides a potential target for diagnosis and treatment of malignant glioma.     

CircATRNL1 increases acid-sensing ion channel 1 to advance epithelial-mesenchymal transition in endometriosis by binding to microRNA-103a-3p

Circular RNA ATRNL1 (circATRNL1) has been implicated in epithelial-mesenchymal transition (EMT) during endometriosis. Given the existing literature and our predictions through starBase in this research, it was assumed that circATRNL1 might orchestrate the microRNA (miR)? 103a-3p/acid-sensing ion channel 1 (ASIC1) axis to control EMT in endometriosis. To verify our hypothesis, we detect circATRNL1, miR-103a-3p, and ASIC1 expression in endometrial cancer cells (HEC-B, AN3-CA, KLE, HEC1-A, and Ishikawa). Ishikawa cells with the highest circATRNL1 level were selected as subjects, where circATRNL1, miR-103a-3p, or ASIC1 expression was knocked down. Scratch and Transwell assays were applied to assess cell migration and invasion, and CCK-8 and colony formation assays to detect cell proliferation. Western blot was used to measure E-cadherin, N-cadherin, Vimentin, and Slug expression to evaluate the EMT state. Furthermore, the binding of miR-103a-3p to circATRNL1 or ASIC1 was validated by luciferase reporter assay. CircATRNL1 and ASIC1 were upregulated but miR-103a-3p was downregulated in endometrial cancer cells. Mechanistically, circATRNL1 bound to miR-103a-3p to upregulate a target gene of miR-103a-3p, ASIC1. CircATRNL1 silencing contributed to the decline of proliferation, invasion, migration, and EMT in Ishikawa cells, while miR-103a-3p inhibitor reversed those changes. In addition, the EMT process was aggravated when miR-103a-3p was inhibited and this process was suppressed by silencing ASIC1 in the presence of downregulated miR-101a-3p. Our study supported that circATRNL1 might be a novel therapeutic candidate target for endometriosis treatment and provided unique insights into the molecular basis concerning the pathogenesis of endometriosis.     

miR-19a-3p在前列腺癌细胞侵袭和迁移中的作用

miR-19a-3p通过多种机制调节癌细胞的增殖和转移,然而,miR-19a-3p在前列腺癌转移中的生物学作用和机制尚不清楚。本研究旨在考察mir-19a-3p在前列腺癌中的表达情况,及其对细胞侵袭和迁移的影响。本研究发现,miR-19a-3p在骨转移性前列腺癌组织和前列腺癌细胞中明显下调。上调miR-19a-3p可显著抑制前列腺癌细胞的侵袭和迁移。然而,下调miR-19a-3p则会逆转上述变化。此外,本研究还发现miR-19a-3p通过靶向TGF-β信号传导的下游效应物SMAD2来抑制前列腺癌细胞中TGF-β信号传导的活性,从而抑制前列腺癌细胞的侵袭和迁移。因此,本研究表明mir-19a-3p与前列腺癌的发生发展密切相关,mir-19a-3p有望成为前列腺癌的新治疗靶点及生物标志物。     

circPVT1通过miR-24-3p/let-7a-5p/FSCN1轴促进鼻咽癌细胞侵袭迁移

目的 鼻咽癌是一种来源于鼻咽上皮的恶性肿瘤,其临床特征之一是易发生淋巴转移,但是目前鼻咽癌转移的分子机制尚未阐明。circPVT1是由PVT1基因2号外显子反向拼接形成的环状RNA (circRNA),在多种肿瘤中表达上调,本文探讨了circPVT1在鼻咽癌侵袭迁移中的作用和分子机制。方法 通过RT-qPCR检测circPVT1及其下游miRNA和FSCN1在鼻咽癌细胞的表达情况,Transwell和划痕愈合实验检测circPVT1对鼻咽癌细胞侵袭迁移的影响,RNA pull-down实验检测circPVT1结合的miRNA,双荧光素酶报告实验检测miR-24-3p和let-7a-5p靶向抑制FSCN1 mRNA表达。结果 在鼻咽癌细胞中过表达circPVT1可以促进鼻咽癌细胞侵袭迁移,而敲低circPVT1则可以抑制鼻咽癌细胞的侵袭迁移。进一步研究发现,circPVT1可以通过竞争性吸附miR-24-3p和let-7a-5p,上调FSCN1的表达,从而促进鼻咽癌细胞的侵袭迁移。结论 circPVT1通过miR-24-3p/let-7a-5p/FSCN1轴促进鼻咽癌细胞侵袭迁移,证实c...     

Inhibition of RAC1-GEF DOCK3 by miR-512-3p contributes to suppression of metastasis in non-small cell lung cancer

MicroRNAs are a class of small non-coding RNAs regulating gene expression. In this study, we demonstrated that retinoic acid (RA) treatment increases the expression of miR-512-3p. Overexpression of miR-512-3p inhibited cell adhesion, migration, and invasion in non-small cell lung cancer (NSCLC) cell lines A549 and H1299. miR-512-3p inhibitor partially reversed these effects in H1299 cells stably expressing miR-512. We identified DOCK3, a RAC1-GEF (guanine nucleotide exchange factor), as a target gene of miR-512-3p. Overexpression of miR-512-3p led to the decrease of DOCK3 protein but not its mRNA. Knockdown of DOCK3 resulted in similar effects on adhesion, migration, and invasion as observed of miR-512-3p overexpression. Active RAC1 pull-down assay indicated that overexpression of miR-512-3p could decrease the activity of RAC1 with a higher efficiency than that of DOCK3 knockdown. Furthermore, expression of miR-512-3p was suppressed in most NSCLC patient tumor samples compared to its paired normal controls, suggesting that miR-512-3p might play a crucial role in lung cancer development. In conclusion, our results supported that miR-512-3p could inhibit tumor cell adhesion, migration, and invasion by regulating the RAC1 activity via DOCK3 in NSCLC A549 and H1299 cell lines.     

Deregulation between miR-29b/c and DNMT3A Is Associated with Epigenetic Silencing of the CDH1 Gene,Affecting Cell Migration and Invasion in Gastric Cancer

The de-regulation of the miR-29 family and DNA methyltransferase 3A (DNMT3A) is associated with gastric cancer (GC). While increasing evidence indicates miR-29b/c could regulate DNA methylation by targeting DNMT3A, it is currently unknown if epigenetic silencing of miR-29b/c via promoter hypermethylation in GC is caused by abnormal expression of DNMT3A. Thus, we aimed to evaluate whether cross-talk regulation exists between miR-29b/c and DNMT3A and whether it is associated with a malignant phenotype in GC. First, wound healing and Transwell assays revealed that miR-29b/c suppresses tumor metastasis in GC. A luciferase reporter assay demonstrated that DNMT3A is a direct target of miR-29b/c. We used bisulfite genomic sequencing to analyze the DNA methylation status of miR-29b/c. The percentage of methylated CpGs was significantly decreased in DNMT3A-depleted cells compared to the controls. Furthermore, the involvement of DNMT3A in promoting GC cell migration was associated with the promoter methylation-mediated repression of CDH1. In 50 paired clinical GC tissue specimens, decreased miR-29b/c was significantly correlated with the degree of differentiation and invasion of the cells and was negatively correlated with DNMT3A expression. Together, our preliminary results suggest that the following process may be involved in GC tumorigenesis. miR-29b/c suppresses the downstream gene DNMT3A, and in turn, miR-29b/c is suppressed by DNMT3A in a DNA methylation-dependent manner. The de-regulation of both of miR-29b/c and DNMT3A leads to the epigenetic silencing of CDH1 and contributes to the metastasis phenotype in GC. This finding reveals that DNA methylation-associated silencing of miR-29b/c is critical for GC development and thus may be a therapeutic target.     

miR-125a-3p调控人结肠癌细胞浸润转移的作用及机制研究

目的:探讨miR-125a-3p在结肠癌细胞浸润与转移中的作用及其可能机制。方法:通过qRT-PCR方法检测miR-125a-3p在结肠癌细胞及组织样本中的表达;在结肠癌细胞过表达或沉默miR-125a-3p后,通过平板克隆实验、MTT实验、划痕实验、Transwell实验检测结肠癌细胞增殖、迁移及侵袭能力的变化;采用Western blot方法检测miR-125a-3p过表达后相关标志分子的表达水平变化情况。结果:miR-125a-3p在结肠癌细胞及组织呈现异常低表达;过表达miR-125a-3p抑制结肠癌细胞HCT116及SW480的增殖能力;过表达或沉默miR-125a-3p分别抑制或增强结肠癌细胞的迁移与侵袭能力;过表达miR-125a-3p在mRNA及蛋白水平均能够显著抑制Snail、N-cadherin及Vimentin的表达,而增加E-cadherin的表达。结论:miR-125a-3p参与调节结肠癌细胞浸润与转移,其机制可能是通过调控上皮间质转化途径介导的。     

DNA methylation-regulated miR-193a-3p dictates resistance of hepatocellular carcinoma to 5-fluorouracil via repression of SRSF2 expression

Chemoresistance prevents effective cancer therapy and is rarely predictable prior to treatment, particularly for hepatocellular carcinoma (HCC). Following the chemoresistance profiling of eight HCC cell lines to each of nine chemotherapeutics, two cell lines (QGY-7703 as a sensitive and SMMC-7721 as a resistant cell line to 5-fluorouracil (5-FU) treatment) were systematically studied for mechanistic insights underpinning HCC 5-FU chemoresistance. Genomic profiling at both DNA methylation and microRNA (miR) levels and subsequent mechanistic studies illustrate a new mechanism for how DNA methylation-regulated miR-193a-3p dictates the 5-FU resistance of HCC cells via repression of serine/arginine-rich splicing factor 2 (SRSF2) expression. In turn, SRSF2 preferentially up-regulates the proapoptotic splicing form of caspase 2 (CASP2L) and sensitizes HCC cells to 5-FU. Forced changes of miR-193a-3p level reverse all of the phenotypic features examined, including cell proliferation, cell cycle progression, and 5-FU sensitivity, in cell culture and in nude mice. Importantly, the siRNA-mediated repression of SRSF2 phenocopies all of the miR-193a-3p mimic-triggered changes in QGY-7703. This newly identified miR-193a-3p-SRSF2 axis highlights a new set of companion diagnostics required for optimal 5-FU therapy of HCC, which involve assaying both the DNA methylation state of the miR-193a gene and the expression of miR-193a-3p and SRSF2 and the relative level of the proapoptotic versus antiapoptotic splicing forms of caspase 2 in clinical samples.     

MiR-216a-3p regulates the proliferation,apoptosis, migration,and invasion of lung cancer cells via targeting COPB2

ABSTRACT

Effect of miR-216a-3p on lung cancer hasn’t been investigated. Here, we explored its effects on lung cancer. MiR-216a-3p expression in lung cancer tissues and cells was detected by RT-qPCR. The target gene of miR-216a-3p was predicted by bioinformatics and confirmed by luciferase-reporter assay. After transfection, cell viability, migration, invasion, proliferation, and apoptosis were detected by MTT, scratch, transwell, colony formation, and flow cytometry. The expressions of COPB2 and apoptosis-related factors were detected by RT-qPCR or western blot. MiR-216a-3p was low-expressed and COPB2 was high-expressed in lung cancer tissues and cells. MiR-216a-3p targeted COPB2 and regulated its expression. MiR-216a-3p inhibited lung cancer cell viability, migration, invasion, and proliferation, while promoted apoptosis. Effect of miR-216a-3p on lung cancer was reversed by COPB2. MiR-216a-3p regulated proliferation, apoptosis, migration, and invasion of lung cancer cells via targeting COPB2.     

Long noncoding RNA SOX21-AS1 regulates the progression of triple-negative breast cancer through regulation of miR-520a-5p/ORMDL3 axis

Recently, long noncoding RNAs (lncRNAs) have been reported as a new kind of controllers about cancer processes in biology. In spite of the dysregulation of lncRNAs in various kinds of cancers, only a little of the information was effective on the expression configuration and inner effects of lncRNAs in triple-negative breast cancer (TNBC). This study valued the expression of lncRNA SOX21-AS1 and the biological role it played in TNBC. In our research, SOX21-AS1 had a high expression in TNBC cell lines. The functional experiments showed that knockdown of SOX21-AS1 obviously restrained cell proliferation, migration, invasion, and epithelial-mesenchymal transition process and promoted cell apoptosis. Mechanistically, SOX21-AS1 was found to bind with miR-520a-5p. Besides, ORMDL3 was identified as a downstream target of miR-520a-5p, and the suppressed ORMDL3 expression induced by silenced SOX21-AS1 could be restored by miR-520a-5p inhibition. Further, data from rescue assays revealed that SOX21-AS1 could regulate the malignancy of TNBC via miR-520a-5p/ORMDL3 axis. All in all, we identified that SOX21-AS1 regulated the cellular process of TNBC cells via antagonizing miR-520a-5p availability to upregulate ORMDL3 expression.     

Retracted: MicroRNA-520a-3p suppresses epithelial–mesenchymal transition,invasion, and migration of papillary thyroid carcinoma cells via the JAK1-mediated JAK/STAT signaling pathway

Papillary thyroid cancer (PTC) is a kind of thyroid cancer and frequently presents with epithelial–mesenchymal transition (EMT). MicroRNAs (miRNAs) were previously reported to be associated with PTC. Thus, this study aims to define the role of microRNA-520a-3p (miR-520a-3p) in PTC through the JAK/STAT signaling pathway by targeting JAK1. The PTC and normal thyroid tissues of 137 PTC patients were collected. First of all, the expression pattern of miR-520a-3p, JAK1, JAK2, STAT3, E-cadherin, and vimentin in PTC was identified. The relationship between miR-520a-3p and JAK1 was predicted and analyzed. And a series of miR-520a-3p mimic or inhibitor, or siRNA JAK1 introduced into PTC cells were applied to examine the effect of miR-520a-3p on PTC cell viability, migration, invasion, cell cycle, apoptosis, and EMT. Meanwhile, the regulatory effect of miR-520a-3p and JAK1 on the JAK/STAT signaling pathway was also determined. The expression of JAK1, JAK2, STAT3, and vimentin increased yet miR-520a-3p and E-cadherin decreased in PTC tissue. JAK1 was negatively regulated by miR-520a-3p. Functionally, EMT induction was prevented by miR-520a-3p upregulation through downregulating JAK1. When upregulating miR-520a-3p or silencing JAK1 in PTC cells, PTC cell viability, migration, and invasion were inhibited yet cell apoptosis promoted with cells arrested at G1 phase, indicating that miR-520a-3p prevented PTC progression by downregulating JAK1. Moreover, miR-520a-3p elevation or JAK1 inhibition inactivated the JAK/STAT signaling pathway. Collectively, miR-520a-3p prevents cancer progression through inactivating the JAK/STAT signaling pathway by downregulating JAK1 in PTC.     

MicroRNA and protein profiles in invasive versus non-invasive oral tongue squamous cell carcinoma cells in vitro

Complex molecular pathways regulate cancer invasion. This study overviewed proteins and microRNAs (miRNAs) involved in oral tongue squamous cell carcinoma (OTSCC) invasion. The human highly aggressive OTSCC cell line HSC-3 was examined in a 3D organotypic human leiomyoma model. Non-invasive and invasive cells were laser-captured and protein expression was analyzed using mass spectrometry-based proteomics and miRNA expression by microarray. In functional studies the 3D invasion assay was replicated after silencing candidate miRNAs, miR-498 and miR-940, in invasive OTSCC cell lines (HSC-3 and SCC-15). Cell migration, proliferation and viability were also studied in the silenced cells. In HSC-3 cells, 67 proteins and 53 miRNAs showed significant fold-changes between non-invasive vs. invasive cells. Pathway enrichment analyses allocated “Focal adhesion” and “ECM-receptor interaction” as most important for invasion. Significantly, in HSC-3 cells, miR-498 silencing decreased the invasion area and miR-940 silencing reduced invasion area and depth. Viability, proliferation and migration weren’t significantly affected. In SCC-15 cells, down-regulation of miR-498 significantly reduced invasion and migration. This study shows HSC-3 specific miRNA and protein expression in invasion, and suggests that miR-498 and miR-940 affect invasion in vitro, the process being more influenced by mir-940 silencing in aggressive HSC-3 cells than in the less invasive SCC-15.     

Aberrant hypermethylation of miR-9 genes in gastric cancer

Carcinogenesis of the stomach involves multiple steps including genetic mutation or epigenetic alteration of tumor suppressor genes or oncogenes. Recently, tumor suppressive miRNAs have been shown to be deregulated by aberrant hypermethylation during gastric cancer progression. In this study, we demonstrate that three independent genetic loci encoding for miR-9 (miR-9-1, miR-9-2 and miR-9-3) are simultaneously modified by DNA methylation in gastric cancer cells. Methylation-mediated silencing of these three miR-9 genes can be reactivated in gastric cancer cells through 5-Aza-dC treatment. Subsequent analysis of the expression levels of miR-9 showed that it was significantly down-regulated in gastric cancers compared with adjacent normal tissues (P value < 0.005). A similar tendency toward a tumor-specific DNA methylation pattern was shown for miR-9-1, miR-9-2 and miR-9-3 in 72 primary human gastric cancer specimens. Ectopic expression of miR-9 inhibited cell proliferation, migration and invasion, suggesting its tumor suppressive potential in gastric cancer progression.