Clinicopathological and prognostic significance of microRNA-107 and its relationship to DICER1 mRNA expression in gastric cancer.
ABSTRACT microRNAs (miRNAs) are small non-coding RNAs that regulate target gene expression. It is known that miRNA-107 (miR-107) promotes cancer invasion and metastasis. However, the relationship between clinicopathological factors and the prognostic significance of miR-107 for gastric cancer patients remains elusive. In this study, we evaluated the prognostic value of miR-107 using tissue samples from gastric cancer patients. Furthermore, the relationship between miR-107 and the mRNA levels of its target gene DICER1 was examined. The expression levels of miR-107 and DICER1 mRNA in tumor tissues and adjacent normal tissues of 161 gastric cancer patients were examined (TNM stage I, 29 patients; stage II, 31 patients; stage III, 51 patients and stage IV, 50 patients). miR-107 levels were measured by Taqman microRNA assays, and DICER1 mRNA levels were measured by the Taqman real-time RT-PCR method. In the analysis by real-time PCR-based miRNA arrays using pooled RNA samples from five gastric cancer patients, expression of miR-107, miR-21, miR-196a, miR-26b, miR-9, miR-142-3p, miR-30b, miR-150, miR-191 and miR-17 was found to be upregulation. The mean expression level of miR-107 was significantly higher in the tumor tissues compared to that of normal tissues. In the comparison of clinicopathological factors, miR-107 expression showed significant association with depth of tumor invasion, lymph node metastasis and stage. In Kaplan-Meier survival curve analysis, overall survival rates (OS) and disease-free survival rates (DFS) of patients with high miR-107 expression were significantly worse than those of patients with low miR-107 expression. In the Cox multivariate analysis, it was shown that miR-107 expression in gastric cancer tissues was an independent prognostic factor for OS and DFS. Significant inverse correlations were demonstrated between miR-107 and DICER1 mRNA. Our results indicate that miR-107 may be useful as an effective biomarker for prediction of a poor prognosis in gastric cancer patients.
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ABSTRACT: miRNAs have emerged as crucial regulators in the regulation of development as well as human diseases, especially tumorigenesis. The aims of this study are to evaluate miR-30b-5p expression pattern and mechanism in gastric carcinogenesis due to which remains to be determined. Expression of miR-30b-5p was analyzed in 51 gastric cancer cases and 4 cell lines by qRT-PCR. The effect of DNA methylation on miR-30b-5p expression was assessed by MSP and BGS. In order to know whether DNMT1 increased miR-30b-5p promoter methylation, DNMT1 was depleted in cell lines AGS and BGC-823. The role of miR-30b-5p on cell migration was evaluated by wound healing assays. Decreased expression of miR-30b-5p was found in gastric cancer samples. In tumor, the expression level of miR-30b-5p was profound correlated with lymph node metastasis (P = 0.019). The level of miR-30b-5p may be restored by DNA demethylation and DNMT1 induced miR-30b-5p promoter methylation. In vitro functional assays implied that enforced miR-30b-5p expression affected cell migration, consistent with tissues analysis. Our findings uncovered that miR-30b-5p is significantly diminished in gastric cancer tissues, providing the first insight into the epigenetic mechanism of miR-30b-5p down-regulation, induced by DNMT1, and the role of miR-30b-5p in gastric cancer carcinogenesis. Overexpression of miR-30b-5p inhibited cell migration. Thus, miR-30b-5p may represent a potential therapeutic target for gastric cancer therapy.Molecular Biology Reports 06/2014; · 2.51 Impact Factor
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ABSTRACT: Background The biological processes and molecular mechanisms underlying miR-107 remain unclear in gastric cancer(GC). In this study, we aimed to investigate the expression, biological functions and mechanisms of miR-107 in GC.Methods Quantitative real-time RT-PCR was used to test miR-107 expression. MTT and colony formation assays were conducted to explore the potential function of miR-107 in human GC cell line SGC7901. The target gene was determined by bioinformatic algorithms, dual luciferase reporter assay, RT-PCR and Western blot.ResultsExpression of miR-107 was significantly elevated in GC cell line than that in gastric epithelial cell line(p¿=¿0.012). We found that miR-107 inhibitor transfection significantly decreased the proliferation of GC cell line, and clone formation rate of miR-107 inhibitor transfected group was significantly lower than that of control group. Luciferase assays using a reporter carrying a putative miR-107 target site in the 3¿untranslated region (3¿-UTR) of cyclin dependent kinase 8 (CDK8) revealed that miR-107 directly targets CDK8. The expression level of CDK8 mRNA and protein in miR-107 inhibitor transfected GC cell line was significantly decreased compared with control group.Conclusion Our findings indicate that miR-107 is upregulated in GC and affects the proliferation of GC cells, partially through the regulation of CDK8.Virtual SlidesThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_164.Diagnostic pathology. 08/2014; 9(1):164.
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ABSTRACT: Gastric cancer is the fourth most common cancer in the world and the second leading cause of cancer-related death. More than 80% of diagnoses occur at the middle to late stage of the disease, highlighting an urgent need for novel biomarkers detectable at earlier stages. Recently, aberrantly expressed microRNAs (miRNAs) have received a great deal of attention as potential sensitive and accurate biomarkers for cancer diagnosis and prognosis. This review summarizes the current knowledge about potential miRNA biomarkers for gastric cancer that have been reported in the publicly available literature between 2008 and 2013. Available evidence indicates that aberrantly expressed miRNAs in gastric cancer correlate with tumorigenesis, tumor proliferation, distant metastasis and invasion. Furthermore, tissue and cancer types can be classified using miRNA expression profiles and next-generation sequencing. As miRNAs in plasma/serum are well protected from RNases, they remain stable under harsh conditions. Thus, potential functions of these circulating miRNAs can be deduced and may implicate their diagnostic value in cancer detection. Circulating miRNAs, as well as tissue miRNAs, may allow for the detection of gastric cancer at an early stage, prediction of prognosis, and monitoring of recurrence and/or lymph node metastasis. Taken together, the data suggest that the participation of miRNAs in biomarker development will enhance the sensitivity and specificity of diagnostic and prognostic tests for gastric cancer.World journal of gastroenterology : WJG. 09/2014; 20(34):12007-12017.