The association between miR-146a gene rs2910164 polymorphism and gastric cancer risk: a meta-analysis

Association of miRNA-146a Gene Polymorphism Rs2910164 with Behcet's Disease: A Meta-analysis

BACKGROUND

A meta-analysis was performed by summarizing relevant researches to evaluate the relationship between miRNA-146a gene polymorphism rs2910164 and Behcet's disease (BD).

METHODS

A systematic search of published studies was conducted in PubMed and Embase. Five eligible studies involving 1167 BD cases and 1662 controls were included in the current meta-analysis.

RESULTS

The results suggested that the polymorphism rs2910164 was correlated with BD susceptibility in all genetic models. In subgroup analysis according to ethnicity, the relationship between this polymorphism and BD was more significant in Caucasians (allele model: OR = 0.49, 95% CI 0.39-0.61; heterozygote model: OR = 0.35, 95% CI 0.26-0.47; homozygote model: OR = 0.29, 95% CI 0.16-0.53; dominant model: OR = 0.34, 95% CI 0.25-0.45; recessive model: OR = 0.56, 95% CI 0.50-0.72) than that in Asians.

CONCLUSION

In conclusion, this meta-analysis indicates that miRNA-146a gene polymorphism rs2910164 G allele confers BD susceptibility, especially in Caucasians.

Association of rs2910164 polymorphism in MiR-146a gene with psoriasis susceptibility: A meta-analysis

The rs2910164 single nucleotide polymorphism (SNP) in miR-146a has been implicated in the etiology of psoriasis in different relevant studies with contradictory conclusions and limited sample size. Therefore, the aim of this study was to undertake a systematic review and meta-analysis to estimate the association between rs2910164 SNP and psoriasis. We searched the databases of PubMed, EMBASE, Web of Science, WanFang, and Chinese National Knowledge Infrastructure (CNKI) to identify relevant literatures published before July 15, 2018. Four case-control studies including 2212 cases and 2274 healthy controls from 4 different countries met the predetermined criteria. The effect size was pooled by odds ratios (ORs) and 95% confidence intervals (95%CIs). Recessive model (CC vs CG+GG) was confirmed to be the optimal model. The results indicated that rs2910164 SNP was significantly associated with psoriasis (OR = 0.74, 95%CI 0.60-0.91, P = .004), and individuals with CC-genotype were predisposed to have decreased risk of psoriasis.

MicroRNAs as non-invasive diagnostic biomarkers for gastric cancer: Current insights and future perspectives

Non-invasive diagnostic biomarkers may contribute to an early identification of gastric cancer (GC) and improve the clinical management. Unfortunately, no sensitive and specific screening biomarkers are available yet and the currently available approaches are limited by the nature of the disease. GC is a heterogenic disease with various distinct genetic and epigenetic events that occur during the multifactorial cascade of carcinogenesis. MicroRNAs (miRNAs) are commonly deregulated in gastric mucosa during the Helicobacter pylori infection and in stepwise manner from chronic gastritis, through preneoplastic conditions such as atrophic gastritis and intestinal metaplasia, to early dysplasia and invasive cancer. Identification of miRNAs in blood in 2008 led to a great interest on miRNA-based diagnostic, prognostic biomarkers in GC. In this review, we provide the most recent systematic review on the existing studies related to miRNAs as diagnostic biomarkers for GC. Here, we systematically evaluate 75 studies related to differential expression of circulating miRNAs in GC patients and provide novel view on various heterogenic aspects of the existing data and summarize the methodological differences. Finally, we highlight several important aspects crucial to improve the future translational and clinical research in the field.

microRNA single polynucleotide polymorphism influences on microRNA biogenesis and mRNA target specificity

microRNAs (miRNAs) are nowadays recognized as an essential component of gene regulatory networks. Furthermore, deregulation of miRNAs expression often contributes to human pathologies. Recently, a substantial number of single nucleotide polymorphism (SNPs) and rare mutations within pri-, pre- and mature miRNA sequences have been reported. These miRNA SNPs have often been associated with human disease. However, due to the complexity of miRNA biogenesis and the genome-wide functional effects of miRNAs, the determination of biological consequences of these miRNA SNPs remains challenging. Despite an increasing number of reports linking miRNA SNPs with human pathologies, few reports have analyzed the mechanism by which miRNA-SNPs contribute to disease pathogenesis. In this review, we discuss how single polynucleotide polymorphisms in miRNAs genes may influence miRNAs expression and function and thus potentially alter disease pathogenesis.

Downregulated miRNA-1269a variant (rs73239138) decreases the susceptibility to gastric cancer via targeting ZNF70

Although emerging evidence has indicated that single nucleotide polymorphisms (SNPs) in microRNAs (miRNAs) are associated with susceptibility to gastric cancer, a limited number of studies have revealed the underlying molecular mechanisms. In the present study, the results suggested that miR-1269a rs73239138 has a role in decreasing the risk of gastric cancer. The level of miR-1269a variant expression was significantly downregulated compared with the wild-type miR-1269a in the gastric cells (Fig. 1). Furthermore, overexpression of miR-1269a inhibited apoptosis of gastric cancer cells. Expression of the miR-1269a variant inhibited the function of miR-1269a by increasing the apoptotic rate and the expression of Bik, Bim and Bak was upregulated consistently. In addition, zinc-finger protein 70 (ZNF70) was identified to be a target gene of miR-1269a, which was downregulated by miR-1269a and upregulated by miR-1269a variant. ZNF70 was indicated to exert a role as a tumor suppressor in gastric cancer. To the best our knowledge, the present study for the first time highlights a critical role of miR-1269a variant rs73239138 in decreasing the susceptibility to gastric cancer by downregulating its expression and targeting ZNF70, which promotes apoptosis of gastric cancer cells. This SNP is indicated to serve as a potential biomarker and therapeutic target for gastric cancer.

Genetic variation rs7930 in the miR-4273-5p target site is associated with a risk of colorectal cancer

PURPOSE

MicroRNAs (miRNAs) are noncoding RNAs that play roles as tumor suppressors or oncogenes by regulating the expression of target genes via binding to seed-match sequences. Polymorphisms in the miRNA-binding site of a target gene can alter miRNA binding and potentially affect the risk of cancer. The objective of this study was to identify single-nucleotide polymorphisms (SNPs) in miRNA-binding sites and assess their involvement in the risk of colorectal cancer (CRC).

MATERIALS AND METHODS

SNPs in the 3' untranslated regions of genes were selected and assessed for their effects on CRC risk in Korean population using participants in Korean Cancer Prevention Study-II. A detailed study was carried out with the SNP rs7930 in the 3' untranslated region of the translocase of outer mitochondrial membrane 20 (TOMM20) gene. A case-control study (1,545 controls and 620 CRC cases) was conducted to analyze the relationship between polymorphism at rs7930 and the risk of CRC. An interacting miRNA was predicted using web-based software programs, and its interaction with rs7930 in CRC cell lines was investigated by using a luciferase assay.

RESULTS

Individuals carrying the rs7930 AG genotype (G allele) had a 1.721-fold increased risk for CRC in comparison with those with the AA genotype (A allele). The miRNA miR-4273-5p was found to specifically interact with the A allele of rs7930 and to suppress the expression of the target gene (TOMM20) in CRC cell lines.

CONCLUSION

rs7930 is an independent genetic risk factor for CRC susceptibility. Our study suggests a mechanism of how this SNP contributes to CRC carcinogenesis.

LncRNA PVT1 regulates prostate cancer cell growth by inducing the methylation of miR-146a

Prostate cancer is the third most common causes of death from cancer in men. Our previous study demonstrated that lncRNA PVT1 was overexpressed and played an oncogenic role in the progression of prostate cancer. However, the molecular mechanism of modulating the prostate cancer tumorigenesis was still unknown. In this study, we aim to investigate the interaction between PVT1 and miR-146a in prostate cancer and reveal the potential mechanism in prostate cancer carcinogenesis. The expression level of miR-146a was assessed by quantitative RT-PCR. The correlation analysis and methylation status analysis was made to confirm the interaction between PVT1 and miR-146a. Biological function analysis was performed through gain-of-function and loss-of-function strategies. Our results showed that miR-146a was downregulated and negatively correlated with PVT1 level in prostate cancer. PVT1 mediated miR-146a expression by inducing the methylation of CpG Island in its promoter. miR-146a overexpression eliminated the effects of PVT1 knockdown on prostate cancer cells. PVT1 regulated prostate cancer cell viability and apoptosis depending on miR-146a. Our study suggested a regulatory relationship between lncRNA PVT1 and miR-146a during the process of the prostate cancer tumorigenesis. PVT1 regulated prostate cancer cell viability and apoptosis depending on miR-146a. It would contribute to the diagnosis, treatment and prognosis of prostate cancer.

MicroRNA Genetic Variation: From Population Analysis to Functional Implications of Three Allele Variants Associated with Cancer

Nucleotide variants in microRNA regions have been associated with disease; nevertheless, few studies still have addressed the allele-dependent effect of these changes. We studied microRNA genetic variation in human populations and found that while low-frequency variants accumulate indistinctly in microRNA regions, the mature and seed regions tend to be depleted of high-frequency variants, probably as a result of purifying selection. Comparison of pairwise population fixation indexes among regions showed that the seed had higher population fixation indexes than the other regions, suggesting the existence of local adaptation in the seed region. We further performed functional studies of three microRNA variants associated with cancer (rs2910164:C > G in MIR146A, rs11614913:C > T in MIR196A2, and rs3746444:A > G in both MIR499A and MIR499B). We found differences in the expression between alleles and in the regulation of several genes involved in cancer, such as TP53, KIT, CDH1, CLH, and TERT, which may result in changes in regulatory networks related to tumorigenesis. Furthermore, luciferase-based assays showed that MIR499A could be regulating the cadherin CDH1 and the cell adhesion molecule CLH1 in an allele-dependent fashion. A better understanding of the effect of microRNA variants associated with disease could be key in our way to a more personalized medicine.

Helicobacter pylori and microRNAs: Relation with innate immunity and progression of preneoplastic conditions

The accepted paradigm for intestinal-type gastric cancer pathogenesis is a multistep progression from chronic gastritis induced by Helicobacter pylori (H. pylori) to gastric atrophy, intestinal metaplasia, dysplasia and ultimately gastric cancer. The genetic and molecular mechanisms underlying disease progression are still not completely understood as only a fraction of colonized individuals ever develop neoplasia suggesting that bacterial, host and environmental factors are involved. MicroRNAs are noncoding RNAs that may influence H. pylori-related pathology through the regulation of the transcription and expression of various genes, playing an important role in inflammation, cell proliferation, apoptosis and differentiation. Indeed, H. pylori have been shown to modify microRNA expression in the gastric mucosa and microRNAs are involved in the immune host response to the bacteria and in the regulation of the inflammatory response. MicroRNAs have a key role in the regulation of inflammatory pathways and H. pylori may influence inflammation-mediated gastric carcinogenesis possibly through DNA methylation and epigenetic silencing of tumor suppressor microRNAs. Furthermore, microRNAs influenced by H. pylori also have been found to be involved in cell cycle regulation, apoptosis and epithelial-mesenchymal transition. Altogether, microRNAs seem to have an important role in the progression from gastritis to preneoplastic conditions and neoplastic lesions and since each microRNA can control the expression of hundreds to thousands of genes, knowledge of microRNAs target genes and their functions are of paramount importance. In this article we present a comprehensive review about the role of microRNAs in H. pylori gastric carcinogenesis, identifying the microRNAs downregulated and upregulated in the infection and clarifying their biological role in the link between immune host response, inflammation, DNA methylation and gastric carcinogenesis.

Polymorphism in miR-146a associated with clinical characteristics and outcomes in gastric cancer patients treated with adjuvant oxaliplatin and fluoropyrimidines

Purpose

Polymorphism in miR-146a (rs2910164) has been reported to be associated with gastric cancer risk in the Chinese population. We aimed at evaluating the relationship between rs2910164 and the clinical characteristics and outcomes in stage IB–III gastric cancer patients treated with adjuvant chemotherapy after surgery.

Materials and methods

Ninety-eight patients with stage IB–III gastric cancer treated with surgical resection followed by adjuvant chemotherapy of oxaliplatin and fluoropyrimidines were included in the analysis. Genomic DNA was extracted from peripheral blood sample of all patients. Polymerase chain reaction-based restriction fragment length polymorphism assay was used to determine the genotypes.

Results

The 2-year disease-free survival rate was 63%, and the 3-year overall survival (OS) rate was 73.4%. In dominant model, we found that rs2910164 GC + CC (G: guanine, C: cytosine) genotype carriers were less likely to develop lymph node metastasis (P=0.059). The 3-year OS was significantly different for patients with or without lymph node metastasis (89.3% vs 63.7%, P=0.015) and for patients with stage I–III disease (100.0%, 88.6%, and 56.9%; P=0.018). The 3-year OS for GC + CC carriers was significantly higher than for GG carriers (75.1% vs 66.7%, P=0.041). After the multivariant Cox regression analysis, histological grade (P=0.033, relative risk: 5.116, 95% confidence interval: 1.145–22.865) and lymph node status (P=0.031, relative risk: 6.648, 95% confidence interval: 1.191–37.118) were found to be independent prognostic factors for these patients.

Conclusion

rs2910164 could be associated with the lymph node metastasis and prognosis of Chinese gastric cancer patients treated with oxaliplatin and fluoropyrimidines after surgical resection.

miR-27a rs895819 polymorphism and risk of cancer in Chinese population: a meta-analysis

OBJECTIVE

Previous studies have evaluated the association between miR-27a rs895819 polymorphism and cancer risk in Chinese population, but the results were inconclusive. The present meta-analysis was conducted to clarify these controversies.

METHODS

A comprehensive search was conducted to identify all relevant case-control studies of miR-27a rs895819 polymorphism and cancer risk in Chinese participants. We calculated odds ratios (ORs) with 95% confidence intervals (CIs) to assess the strength of any association.

RESULTS

A total of 12 case-control studies involving 2655 cases and 3106 controls were included. Overall, the results suggested that there was no significant association between miR-27a rs895819 polymorphism and cancer risk in Chinese population (OR = 1.14, 95%CI 0.86 to1.15, P = 0.85 for GG vs. AA). In the subgroup analysis by the source of controls, no significant association was found either among hospital-based group (OR = 1.16, 95%CI 0.78 to 1.73) or population-based group (OR = 1.06, 95%CI 0.74 to 1.35). However, when stratified by cancer types, we found a significant association between the polymorphism with colorectal cancer (OR = 1.56, 95%CI 1.01 to 2.40 for GG vs. AA).

CONCLUSION

miR-27a rs895819 polymorphism was associated with increased risk of colorectal cancer in Chinese population.