Functional polymorphisms in the promoter region of miR-17-92 cluster are associated with a decreased risk of colorectal cancer

The microRNA Let-7 and its exosomal form: Epigenetic regulators of gynecological cancers

Many types of gynecological cancer (GC) are often silent until they reach an advanced stage, and are therefore often diagnosed too late for effective treatment. Hence, there is a real need for more efficient diagnosis and treatment for patients with GC. During recent years, researchers have increasingly studied the impact of microRNAs cancer development, leading to a number of applications in detection and treatment. MicroRNAs are a particular group of tiny RNA molecules that regulate regular gene expression by affecting the translation process. The downregulation of numerous miRNAs has been observed in human malignancies. Let-7 is an example of a miRNA that controls cellular processes as well as signaling cascades to affect post-transcriptional gene expression. Recent research supports the hypothesis that enhancing let-7 expression in those cancers where it is downregulated may be a potential treatment option. Exosomes are tiny vesicles that move through body fluids and can include components like miRNAs (including let-7) that are important for communication between cells. Studies proved that exosomes are able to enhance tumor growth, angiogenesis, chemoresistance, metastasis, and immune evasion, thus suggesting their importance in GC management.

MicroRNAs and 'Sponging' Competitive Endogenous RNAs Dysregulated in Colorectal Cancer: Potential as Noninvasive Biomarkers and Therapeutic Targets

The gastrointestinal (GI) tract in mammals is comprised of dozens of cell types with varied functions, structures, and histological locations that respond in a myriad of ways to epigenetic and genetic factors, environmental cues, diet, and microbiota. The homeostatic functioning of these cells contained within this complex organ system has been shown to be highly regulated by the effect of microRNAs (miRNA). Multiple efforts have uncovered that these miRNAs are often tightly influential in either the suppression or overexpression of inflammatory, apoptotic, and differentiation-related genes and proteins in a variety of cell types in colorectal cancer (CRC). The early detection of CRC and other GI cancers can be difficult, attributable to the invasive nature of prophylactic colonoscopies. Additionally, the levels of miRNAs associated with CRC in biofluids can be contradictory and, therefore, must be considered in the context of other inhibiting competitive endogenous RNAs (ceRNA) such as lncRNAs and circRNAs. There is now a high demand for disease treatments and noninvasive screenings such as testing for bloodborne or fecal miRNAs and their inhibitors/targets. The breadth of this review encompasses current literature on well-established CRC-related miRNAs and the possibilities for their use as biomarkers in the diagnoses of this potentially fatal GI cancer.

MicroRNAs as important contributors in the pathogenesis of colorectal cancer

Colorectal cancer (CRC) is the third most fatal and fourth most frequently diagnosed neoplasm in the world. Numerous non-coding RNAs have been shown to contribute in the development of CRC. MicroRNAs (miRNAs) are among the mostly assessed non-coding RNAs in CRC. These transcripts influence expression and activity of TGF-β, Wnt/β-catenin, MAPK, PI3K/AKT and other CRC-related pathways. In the context of CRC, miRNAs interact with long non-coding RNAs to influence CRC course. Stool and serum levels of miRNAs have been used to distinguish CRC patients from healthy controls, indicating diagnostic roles of these transcripts in CRC. Therapeutic application of miRNAs in CRC has been assessed in animal models, yet has not been verified in clinical settings. In the current review, we have provided a recent update on the role of miRNAs in CRC development as well as diagnostic and prognostic approaches.

MIR17HG polymorphism (rs7318578) is associated with liver cancer risk in the Chinese Han population

Numerous evidence has revealed that single-nucleotide polymorphisms (SNPs) are associated with liver cancer risk. To assess whether the MIR17HG polymorphisms are associated with the liver cancer risk in the Chinese Han population, we performed a case–control (432 liver cancer patients and 430 healthy controls) study. Genotyping of four variants of MIR17HG was performed with the Agena MassARRAY platform. We used χ² test to compare the distribution of SNPs allele and genotypes frequencies of cases and controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by logistic regression analysis to evaluate the association under genetic models. The results indicated that the rs7318578 was significantly associated with increased the risk of liver cancer in the allele (OR = 1.45, 95% CI: 1.18–1.77, P=3.04E-04), recessive (OR = 3.69, 95% CI: 2.45–5.56, P=4.52E-10) and additive model (OR = 1.35, 95% CI: 1.13–1.62, P=0.001). Moreover, we found that individuals with the genotype CC of rs7318578 presented with an increased risk of liver cancer (OR = 3.03, 95% CI: 1.98–4.65, P=3.83E-07); however, the CA genotype of rs7318578 significantly decreased the risk of liver cancer (OR = 0.61, 95% CI: 0.45–0.83, P=0.001, compared with those with the AA genotype. Our findings indicated that MIR17HG polymorphism (rs7318578) contributes to liver cancer susceptibility to the Chinese Han population. Further studies with larger samples are required to confirm the results, as well as functional studies to determine the role of this SNP in miRNA expression or molecular pathways.

Role of miRNA gene variants in the susceptibility and pharmacogenetics of colorectal cancer

Colorectal cancer (CRC) is one of the most significant challenges in the field of cancer pathology. miRNAs are among the genetic factors associated with the disease. Although many studies have reviewed the expression patterns of various miRNAs in CRC, few studies have focused on different variants of miRNA. In the present review, miRNA variants have been categorized into three subgroups, including miRNA variants that predict susceptibility to CRC, miRNA variants that predict the clinical parameters of CRC and finally, miRNA variants that predict the pharmacological aspects of CRC. Moreover, a comprehensive review of potentially functional miRNA-associated SNPs as well as their importance as candidate cancer biomarkers are discussed.

Interaction of miR-181b and IFNA1 Polymorphisms on the Risk of Systemic Lupus Erythematosus

Introduction

A previous work has discovered that chromosome 1q32 locus linked to the risk of systemic lupus erythematosus (SLE) and miR-181b located on the susceptibility site with downregulation inversely correlating to its target molecular interferon alpha 1 (IFNA1). The purpose of this study was to investigate the association of miR-181b and IFNA1 polymorphisms with IS risk.

Methods

The miR-181b rs322931, IFNA1 rs1332190, and rs10811543 were genotyped using a Multiplex SNaPshot assay. miR-181b expression levels in plasma of SLE patients and controls were analyzed using quantitative PCR.

Results

The rs322931 CT, CT/TT, and T allele exerted an increased trend of SLE risk (CT vs. CC: adjusted OR = 1.71, 95% CI 1.16-2.50, P = 0.01; CT/TT vs. CC: adjusted OR = 1.45, 95% CI 1.08-1.95, P = 0.01; T vs. C: adjusted OR = 1.38, 95% CI 1.07-1.79, P = 0.01). Combined genotypes of the rs322931 CT/TT+rs1332190 TT and the rs322931 CC+rs10811543 AG/AA also revealed an increased risk of SLE. Gene-gene interaction analysis showed that a three-locus model consisting of rs322931, rs1332190, and rs10811543 attributed an increased risk of SLE. Further genotype-phenotype analysis revealed that rs322931 CT/TT carriers displayed lower levels of miR-181b.

Conclusions

These findings indicate that the miR-181b rs322931 may be singly and jointly responsible for the etiology of SLE by altering miR-181b expression.

Interaction analysis of miR-1275/IGF2BP1/IGF2BP3 with the susceptibility to hepatocellular carcinoma

Aim: The aim of this study was to investigate the association of miR-1275 rs16759, IGF2BP1 rs11079850 and IGF2BP3 rs34414305 with hepatocellular carcinoma (HCC) risk. Materials & methods: Genotyping of the rs16759 and rs11079850 was performed using a Taqman assay and genotyping of the rs34414305 was performed using PCR. Relative expression of miR-1275, IGF2BP1 and IGF2BP3 was examined using quantitative PCR. Results: Comparison of the rs16759GG, CG/GG and CC genotype showed an increased risk of HCC. When comparing G with C allele, a significantly increased risk of HCC was also found. The rs16759, rs11079850 and rs34414305 had combined the interactive effects on the carcinogenesis of HCC. Moreover, the rs34414305 Del/ATT-Del/Del carriers displayed lower levels of IGF2BP3. Conclusion: The rs16759, rs11079850 and rs34414305 may singly and interactively contribute to carcinogenesis of HCC.

A Functional Polymorphism in the Promoter of miR-17-92 is Associated with a Reduced Risk of Cervical Squamous Cell Carcinoma

miR-17-92 cluster was differentially expressed in cervical cancer, playing an important role in regulating cell proliferation, apoptosis, migration, and invasion. The purpose of this study was to investigate the association between polymorphisms (i.e., rs9588884, rs982873, and rs1813389) in the promoter of miR-17-92 and the risk of cervical squamous cell carcinoma (CSCC). The rs9588884 polymorphism was genotyped using a Taqman assay and the rs982873 and rs1813389 polymorphisms were genotyped using a polymerase chain reaction-restriction fragment length polymorphism method. The expression levels of miR-17-92 were determined using a quantitative PCR analysis. The rs9588884 GG genotype was associated with a reduced risk of CSCC in homozygote comparison (adjusted OR = 0.47, 95% CI, 0.30-0.75, P = 0.001), dominant model (adjusted OR = 0.67, 95% CI, 0.50-0.91, P = 0.01), and recessive model (adjusted OR = 0.57, 95% CI, 0.38-0.85, P = 0.01). The rs9588884 G allele was also associated with a reduced risk of CSCC in allele comparison (adjusted OR = 0.71, 95% CI, 0.58-0.88, P = 0.002). Moreover, patients with the rs9588884 GG genotype had lower levels of miR-20a compared with the rs9588884 CC genotype (P = 0.03). These findings indicate that the rs9588884 GG genotype was associated with lower levels of miR-20a and eventually related to the risk of CSCC in Chinese women.

A functional polymorphism in the promoter of miR-17-92 cluster is associated with decreased risk of ischemic stroke

Background

The microRNA-17-92 (miR-17-92) cluster is one of the most extensively studied miRNA clusters. Abnormal expression of the cluster has been found to play important role in different kinds of human diseases, including ischemic stroke (IS). The aim of our study was to investigate the association between three polymorphisms (rs1491034, rs9301654 and rs982873) in the promoter of the miR-17-92 cluster and risk of IS.

Methods

Three hundred and ninety-eight patients with IS and 397 control subjects were included. The genotypes of the three polymorphisms were determined by Snapshot SNP genotyping assay. Relative expression of the cluster in peripheral blood mononuclear cells (PBMCs) of cases and controls were examined by quantitative real-time PCR.

Results

Significant association between rs9301654 polymorphism and risk of IS were observed basing on genotype, model and allele analyses (GA vs. AA: adjusted OR = 0.63, 95% CI: 0.41~0.97, P = 0.037; GG vs. AA: adjusted OR = 0.23, 95% CI: 0.07~0.78, P = 0.018; GA + GG vs. AA: adjusted OR = 0.57, 95% CI: 0.38~0.87, P = 0.009; GA + AA vs. GG: adjusted OR = 0.27, 95% CI: 0.08~0.89, P = 0.032; G vs. A: adjusted OR = 0.58, 95% CI: 0.40~0.83). Haplotype analysis showed that TGC and TGT haplotypes were associated with decreased risk of IS (OR = 0.59, 95% CI: 0.40~0.87, P = 0.007 for TGC haplotype; OR = 0.21, 95% CI: 0.06~0.75, P = 0.009 for TGT haplotype). Importantly, we found the expression of miR-17-5p was significant higher while miR-19a-3p was significant lower in patient with IS compared with the control group (P < 0.01), and patients with rs9301654GG or GA genotype displayed lower level of miR-19a-3p compared with the AA genotype (P < 0.01).

Conclusions

Our findings indicated that rs9301654 polymorphism in the promoter of miR-17-92 cluster may be associated with susceptibility of IS in the Chinese population. However, we found that rs9301654 polymorphism and its respective gene expression did not demonstrate consistent association with IS in the Chinese population. Further studies such as gene-gene interaction are warranted to reveal the role of miR-19a and its regulatory genes in the etiology of IS.

A functional variant in the flanking region of pri-let-7f contributes to colorectal cancer risk in a Chinese population

Let-7f was reported to be downregulated in patients with colorectal cancer (CRC). However, little is known about the role of let-7f in CRC carcinogenesis. The aim of this study was to investigate the correlation between genetic polymorphisms in the flanking region of pri-let-7f and CRC risk, as well as the potential role of let-7f in CRC cell migration and invasion. The pri-let-7f-1 rs10739971 and pri-let-7f-2 rs17276588 were genotyped using TaqMan (Applied Biosystems, Foster City, CA) assay. The luciferase activity was detected using Dual-Luciferase Reporter Assay. CRC cell migration and invasion were evaluated using transwell chamber assay. The rs17276588 AG and AG/AA genotypes had a significantly increased CRC risk (AG vs. GG: adjusted odds ratio [OR] = 1.48, 95% confidence interval [CI] = 1.19-1.83, p < 0.001; AG/AA vs. GG: adjusted OR = 1.43, 95% CI = 1.17-1.75, p < 0.001). Stratification analyses showed that the increased risk was observed in CRC patients with well-moderately differential status, patients with clinical Stages I-II, and patients without lymph node metastasis. The rs17276588A allele displayed a decreased transcriptional activity and low levels of let-7f. Moreover, let-7f inhibited migration and invasion in Caco-2 and Lovo cells. These findings indicate that the rs17276588 AG/AA genotypes increased CRC risk by reducing the expression of tumor suppressor let-7f.

miR-30a promoter variation contributes to the increased risk of colorectal cancer in an Iranian population

Cytochrome P450 family 24 subfamily A member 1 (CYP24A1) gene is overexpressed in many cancers including colorectal cancer (CRC) and correlated with tumor invasion, lymph node metastasis, and the reduced overall survival. We predicted that miR-30a and miR-125a regulate the CYp24A1 gene expression. Therefore, we performed a case-control study using 800 individuals, including 389 patients with CRC and 411 noncancer controls to evaluate the association between miR-30a rs2222722 and miR-125a rs12976445 polymorphisms, located at in the promoter region, and the risk of sporadic CRC in an Iranian population. The genotyping assay for both polymorphisms was performed using Tetra-primer amplification refractory mutation systems polymerase chain reaction. The results indicated that the frequency of the miR-30a rs2222722 CT genotype was significantly different in the studied groups ( P = 0.0001; odds ratio [OR] = 1.9; 95% confidence interval [CI], 1.39-2.60). Also, a significant difference was observed under the dominant inheritance model ( P = 0.0001; OR = 1.8; 95% CI, 1.33-2.43). The frequency of the miR-30a rs2222722 T allele was significantly associated with increased CRC risk in the studied population ( P = 0.0019; OR = 1.47; 95% CI, 1.15-1.89). Taken together, our study provides preliminary evidence that the rs2222722 polymorphism increases the susceptibility to CRC in an Iranian population. Therefore, the affecting factors on CYP24A1 gene expression such as microRNAs can be considered as risk factors for CRC.

Association between polymorphisms of MIR17HG and risk of colorectal cancer in the Chinese Han population

Background

Colorectal cancer is the third most common cancer worldwide. Recently, an increasing number of evidences suggest that genetic susceptibility plays an important role in the occurrence of colorectal cancer. This study aimed to better understand the influence of MIR17HG polymorphisms on colorectal cancer susceptibility in the Chinese Han population.

Methods

We recruited 514 patients with colorectal cancer and 510 healthy controls to investigate the association between polymorphisms of MIR17HG and risk of colorectal cancer in the Chinese Han population. Genotyping was performed with the Agena MassARRAY platform. We used the χ² test to compare the distributions of single nucleotide polymorphisms (SNPs) allele and genotypes frequencies between cases and controls. Odds ratios and 95% confidence intervals were calculated by logistic regression analysis to evaluate the association under genetic models. Linkage disequilibrium between the five SNPs was assessed using the Haploview software.

Results

Overall analysis found that rs7336610 and rs1428 and haplotype CTAGA were significantly associated with increased risk of colorectal cancer. However, we found rs7318578 was associated with a decreased risk of colorectal cancer in the dominant model. Stratification analysis showed that rs7336610, rs7318578, and rs1428 were also associated with rectal cancer risk. Gender stratification analysis found that rs7336610, rs7318578, rs17735387, and rs1428 were significantly associated with colorectal cancer risk in males.

Conclusion

In conclusion, this study indicated that the polymorphisms of MIR17HG were associated with colorectal cancer risk. Therefore, our findings may provide new insights into the development of colorectal cancer. Further association and functional studies are of great importance to confirm these results and to define the potential biological mechanism of colorectal cancer.

Single Nucleotide Polymorphism in SMAD7 and CHI3L1 and Colorectal Cancer Risk

Colorectal cancer (CRC) is one of the leading cancers throughout the world. It represents the third most common cancer and the fourth in mortality. Most of CRC are sporadic, arise with no known high-penetrant genetic variation and with no previous family history. The etiology of sporadic CRC is considered to be multifactorial and arises from the interaction of genetic variants of low-penetrant genes and environmental risk factors. The most common well-studied genetic variation is single nucleotide polymorphisms (SNPs). SNP arises as a point mutation. If the frequency of the sequence variation reaches 1% or more in the population, it is referred to as polymorphism, but if it is lower than 1%, the allele is typically considered as a mutation. Lots of SNPs have been associated with CRC development and progression, for example, genes of TGF-β1 and CHI3L1 pathways. TGF-β1 is a pleiotropic cytokine with a dual role in cancer development and progression. TGF-β1 mediates its actions through canonical and noncanonical pathways. The most important negative regulatory protein for TGF-β1 activity is termed SMAD7. The production of TGF-β can be controlled by another protein called YKL-40. YKL-40 is a glycoprotein with an important role in cancer initiation and metastasis. YKL-40 is encoded by the CHI3L1 gene. The aim of the present review is to give a brief introduction of CRC, SNP, and examples of some SNPs that have been documented to be associated with CRC. We also discuss two important signaling pathways TGF-β1 and CHI3L1 that influence the incidence and progression of CRC.

MicroRNA-17 as a promising diagnostic biomarker of gastric cancer: An investigation combining TCGA, GEO, meta-analysis, and bioinformatics

Integrated studies of accumulated data can be performed to obtain more reliable information and more feasible measures for investigating potential diagnostic biomarkers of gastric cancer (GC) and to explore related molecular mechanisms. This study aimed to identify microRNAs involved in GC by integrating data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus. Through our analysis, we identified hsa‐miR‐17 (miR‐17) as a suitable candidate. We performed a meta‐analysis of published studies and analyzed clinical data from TCGA to evaluate the clinical significance and diagnostic value of miR‐17 in GC. miR‐17 was found to be upregulated in GC tissues and exhibited a favorable value in diagnosing GC. In addition, we predicted that 288 target genes of miR‐17 participate in GC‐related pathways. Enrichment of Kyoto Encyclopedia of Genes and Genomes pathway, Gene Ontology analysis, and protein–protein interaction analysis of the 288 target genes of miR‐17 were also performed. Through this study, we identified possible core pathways and genes that may play an important role in GC. The possible core pathways include the cAMP, phosphoinositide‐3‐kinase–Akt, Rap1, and mitogen‐activated protein kinase signaling pathways. miR‐17 may be involved in several biological processes, including DNA template transcription, the regulation of transcription from RNA polymerase II promoters, and cell adhesion. In addition, cellular components (such as cytoplasm and plasma membrane) and molecular functions (such as protein binding and metal ion binding) also seemed to be regulated by miR‐17.

Biology of MiR-17-92 Cluster and Its Progress in Lung Cancer

MicroRNAs, a class of short endogenous RNAs, acting as post-transcriptional regulators of gene expression, mostly silence gene expression via binding imperfectly matched sequences in the 3'UTR of target mRNA. MiR-17-92, a highly conserved gene cluster, has 6 members including miR-17, miR-18a, miR-19a, miR-20a, miR-19b-1 and miR-92a. The miR-17-92 cluster, regarded as oncogene, is overexpressed in human cancers. Lung cancer is the leading cause of death all over the world. The molecular mechanism of lung cancer has been partly known at the levels of genes and proteins in last decade. However, new prognosis biomarkers and more target drugs should be developed in future. Therefore, noncoding RNAs, especially miRNAs, make them as new potentially clinical biomarkers for diagnosis and prognosis. In this review, we focus the current progress of miR-17-92 cluster in lung cancer.