The association between two polymorphisms in pre-miRNAs and breast cancer risk: a meta-analysis

The genetic variants of miR-1206 and miR-125b in breast cancer patients: in vitro and in silico analysis

BACKGROUND

This study aimed to investigate the association of rs12976445 polymorphism in the promoter region of miR-125a and rs2114358 in the precursor region of miR-1206 to breast cancer susceptibility.

METHOD

A total of 230 participants (110 breast cancer and 120 controls) enrolled in this study and extracted genomic DNA. The genotypes were determined by the Tetra-ARMS method. The allele and genotype frequencies were determined.

RESULTS

Allele variation in the rs12976445 (miR-125a) sequence increased the risk of breast cancer; a significant relationship was observed between breast cancer and allele change in individuals with the C allele (p = 0.01). However, allele variation in the rs2114358 (miR-1206) decreased the risk of breast cancer in individuals with allele A (p = 0.01). In silico study showed that allele change was associated with a reduction in structural stability.

CONCLUSION

Therefore, the rs12976445 variant can be considered a risk factor for breast cancer, and the rs2114358 variant is a protective factor against it.

MicroRNA editing patterns in Huntington's disease

Huntington's disease (HD) is a neurodegenerative disease. MicroRNAs (miRNAs) are small non-coding RNAs that mediate post-transcriptional regulation of target genes. Although miRNAs are extensively edited in human brains, the editome of miRNAs in brains of HD patients is largely unknown. By analyzing the small RNA sequencing profiles of brain tissues of 28 HD patients and 83 normal controls, 1182 miRNA editing sites with significant editing levels were identified. In addition to 27 A-to-I editing sites, we identified 3 conserved C-to-U editing sites in miRNAs of HD patients. 30 SNPs in the miRNAs of HD patients were also identified. Furthermore, 129 miRNA editing events demonstrated significantly different editing levels in prefrontal cortex samples of HD patients (HD-PC) when compared to those of healthy controls. We found that hsa-mir-10b-5p was edited to have an additional cytosine at 5'-end in HD-PC, and the edited hsa-mir-10b repressed GTPBP10 that was often downregulated in HD. The down-regulation of GTPBP10 might contribute to the progression of HD by causing gradual loss of function of mitochondrial. These results provide the first endeavor to characterize the miRNA editing events in HD and their potential functions.

Associations of Single Nucleotide Polymorphism in miR-146a Gene with Susceptibility to Breast Cancer in the Iranian Female

BACKGROUND

MicroRNAs (miRNAs), short regulatory RNAs, function as negative regulators able to modulate gene expression. Just as other genetic variant, single nucleotide polymorphisms (SNPs) in miRNA genes, may have an impact on their expression and/or maturation and hence leading to different consequences in carcinogenesis. Accordingly, this study aimed to assess the frequency of miR-146a G/C (rs2910164) polymorphism and its association with susceptibility to breast cancer in Iranian women.

METHODS

We conducted a case-control study using Tetra ARMS polymerase chain reaction (Tetra ARMS PCR) method in 100 Iranian female participants (50 breast cancer patients and 50 controls). Besides, a number of sequenced samples were chosen to confirm the accuracy of genotyping by Tetra ARMA PCR. SPSS software was utilized for all statistical analyses. The odds ratios (ORs) and 95% confidence intervals (95% CIs) were applied to analyze the association between the SNP frequency and breast cancer.

RESULTS

The frequency of genotypes for G/G, G/C, and C/C were 23 (46%), 26 (52%), and 1 (2%) among cases and 15 (30%), 33 (66%), and 2(4%) among controls, respectively. The results generated by the groups did not show any significant correlation between miR-146a G/C (rs2910164) polymorphism and breast cancer, either at genotype or allele levels (P>0.05). F-SNP-based in silico analysis indicated possible modifications in transcriptional regulations induced by miR-146a G/C (rs2910164) variations.

CONCLUSION

Overall, our results indicated no correlation between miR-146a G/C (rs2910164) polymorphism and genetic susceptibility to breast cancer in Iranian female populations. However, these findings need to be further confirmed by analyses of a larger number of cases.

Predictive role of single nucleotide polymorphism (rs11614913) in the development of breast cancer in Pakistani population

Aim: miRNAs play an important role in breast cancer (BC). Variations in miRNAs influence their maturation, expression and consequently regulation of their target genes. Materials & methods: In this study, single nucleotide polymorphism rs11614913 was genotyped in BC patients (n = 300) and 230 controls by employing tetra primer amplification refractory mutation system PCR and Sanger sequencing (Macrogen Korea). Results: A significant difference was observed in the genotypes through co-dominant (χ².#x00A0;= 42.03; p < 0.0001), additive (odds ratio [OR] = 0.6441 [0.4887-0.8490, 95% confidence interval]; p < 0.0019), dominant (OR = 0.3996 [0.2809-0.5686], p < 0.0001) and recessive (OR = 0.2993 [0.1220-0.7347], p < 0.009) statistical models showed decreased risk association of C allele with BC. Conclusion: Females having CT genotype are at higher risk of BC as compared with those having CC genotype.

Long Noncoding RNA HULC Promoter Polymorphism rs1041279 Is Associated with an Increased Risk of Cervical Squamous Cell Carcinoma

Hepatocellular carcinoma upregulated long noncoding RNA (HULC), identified as an oncogene in cervical cancer, is involved in not only the clinical stage, lymph node metastasis, and depth of cervical invasion but also outcome. In this study, we aimed to investigate the association between 3 polymorphisms (i.e., rs1041279, rs3005167, and rs7770772) in the promoter of HULC and the risk of cervical squamous cell carcinoma (CSCC). The polymorphisms were genotyped using the multiplex ligase detection reaction assay. The promoter activity was measured using the dual-luciferase reporter assay kit. The rs1041279 GG genotype and G allele revealed a significantly higher risk of CSCC compared with the rs1041279 CC genotype and C allele (GG vs. CC, adjusted OR = 1.79, 95% CI, 1.17-2.73, P = 0.007; G vs. C, adjusted OR = 1.36, 95% CI, 1.09-1.69, P = 0.006). Haplotype analysis revealed that the rs3005167C-rs7770772G-rs1041279C or rs3005167C-rs7770772G-rs1041279G haplotype had a significantly higher risk of CSCC compared to the rs3005167G-rs7770772G-rs1041279C haplotype (CGC vs. GGC, OR = 2.38, 95% CI, 1.53-3.75, P < 0.001; CGG vs. GGC, OR = 3.76, 95% CI, 2.12-6.68, P < 0.001). Dual-luciferase reporter assay showed that the rs1041279 G promoter resulted in higher transcriptional activity compared with the rs1041279 C (P < 0.01). Additionally, the rs1041279 GG genotype carriers had an increased level of HULC expression (P = 0.03). These findings suggest that the HULC rs1041279 may be a useful marker for the etiology of CSCC.

rs187960998 polymorphism in miR-211 prevents development of human colon cancer by deregulation of 3'UTR in CHD5

Background

Previous research indicated that overexpression of miRNA-211 could promote colorectal cancer cell growth by targeting tumor suppressive gene Chromodomain-helicase-DNA-binding protein 5 (CHD5) in human colon cancer (CC). Moreover, the function of the single-nucleotide polymorphism (SNP) located in the mature region of miR-211 has not been investigated. In this study, we found that SNP of rs187960998 in miR-211 was involved in the occurrence of CC by acting as a tumor suppressor by mal-regulation of its target gene CHD5.

Materials and methods

The genotype of total 685 CC patients was detected by real-time PCR, the proliferation of CC cell lines with different genotypes of miR-211 was determined by Cell Counting Kit-8, cell invasion evaluated by transwell and the activity of the CHD5 promoter in CC cell lines transfected with different miR-211 was determined by luciferase assay. The expression of CHD5 in CC patients was determined by the immunohistochemistry, and the relapse-free survival rate was analyzed by Kaplan–Meier analysis.

Results

C/T SNP of miR-211 could inhibit CC cell proliferation and invasion by upregulation of CHD5. And SNP in rs187960998 of miR-211 was associated with tumor size, metastasis and tumor differentiation in CC patients. Patients with CC genotype have significantly low CHD5 expression than the T-carrier, while no significant expression difference in miR-211 expression among different genotype subsets. Patients with CC genotype have significantly shorter postsurgery survival rate compared to the T-carrier.

Conclusion

rs187960998 in miR-211 was highly associated with a decreased risk of CC in the Chinese population by deregulating a tumor suppressive gene CHD5.

Association of miRNA-146a rs2910164 and miRNA-196 rs11614913 polymorphisms in patients with ulcerative colitis: A meta-analysis and review

BACKGROUND

It has been reported that the single nucleotide polymorphisms (SNPs) miRNA-196 (miR-196) rs11614913 and miRNA-146a (miR-146a) rs2910164 are related to susceptibility to ulcerative colitis (UC). Because the previously reported results have been mixed and uncertain, the aim of this study was to perform a meta-analysis and review to assess the relationship between these 2 SNPs and UC risk.

METHODS

In this analysis, 5 studies involving 1023 cases and 1769 controls for miR-196 rs11614913 and 4 studies involving 827 cases and 1451 controls for miR-146 rs2910164 were included. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were used to pool the effect size.

RESULTS

A decreased risk of UC was identified in homozygote comparison (GG vs CC: OR = 0.69, 95% CI: 0.52-0.93, P = .02), recessive comparison (GG vs CG + CC: OR = 0.74, 95% CI: 0.59-0.92, P = .007), and dominant comparison (GG + CG vs CC: OR = 0.79, 95% CI: 0.65-0.97, P = .02) of miR-146 rs2910164 in Asian but not Caucasian population. No evidence of an association was shown between the rs11614913 polymorphism and UC risk in allelic, heterozygote, homozygote, recessive, and dominant models in both Caucasian and Asian populations (P > .05).

CONCLUSIONS

MiR-146 rs2910164, but not miR-196 rs11614913, was associated with a decreased risk of UC in Asian population. However, the results should be treated with caution because of the limited sample size and heterogeneity. Well-designed studies with large sample sizes and more ethnic groups are needed to validate the risks identified in the current meta-analysis and review.

Genetic Variants in pre-miR-146a, pre-miR-499, pre-miR-125a, pre-miR-605, and pri-miR-182 Are Associated with Breast Cancer Susceptibility in a South American Population

Breast cancer (BC) is one of the most frequent tumors affecting women worldwide. microRNAs (miRNAs) single-nucleotide polymorphisms (SNPs) likely contribute to BC susceptibility. We evaluated the association of five SNPs with BC risk in non-carriers of the BRCA1/2-mutation from a South American population. The SNPs were genotyped in 440 Chilean BRCA1/2-negative BC cases and 1048 controls. Our data do not support an association between rs2910164:G>C or rs3746444:A>G and BC risk. The rs12975333:G>T is monomorphic in the Chilean population. The pre-miR-605 rs2043556-C allele was associated with a decreased risk of BC, both in patients with a strong family history of BC and in early-onset non-familial BC (Odds ratio (OR) = 0.5 [95% confidence interval (CI) 0.4⁻0.9] p = 0.006 and OR = 0.6 [95% CI 0.5⁻0.9] p = 0.02, respectively). The rs4541843-T allele is associated with increased risk of familial BC. This is the first association study on rs4541843 and BC risk. Previously, we showed that the TOX3-rs3803662:C>T was significantly associated with increased risk of familial BC. Given that TOX3 mRNA is a target of miR-182, and that both the TOX3 rs3803662-T and pri-miR-182 rs4541843-T alleles are associated with increased BC risk, we evaluated their combined effect. Risk of familial BC increased in a dose-dependent manner with the number of risk alleles (p-trend = 0.0005), indicating an additive effect.

miRNA 196a2(rs11614913) & 146a(rs2910164) polymorphisms & breast cancer risk for women in an Iranian population

AIM

The purpose of our study was to analyze association of miRNAs 146aG/C(2910164) and 196a2C/T(11614913) polymorphism with breast cancer (BC) risk for women of Azeri ethnicity in Iran.

MATERIALS & METHODS

In the current case (n = 200)-control (n = 200) study, miRNAs 146aG/C(2910164) and 196a2C/T(11614913) were investigated for allelic and genotypic levels via the PCR-restriction fragment length polymorphism technique.

RESULTS

The statistical analysis showed a significant relation between CC genotype of rs11614913(196a2) (codominant, odds ratio (OR) = 0.58, p = 0.02236; recessive, OR = 2.92, p = 0.01695; overdominant, OR = 0.44, p = 0.0113) and BC susceptibility. The subgroup analysis of mentioned polymorphism declared the significant correlation (p ≤ 0.05) of the positive abortion, regular menstruation, positive human epidermal receptor-2 and positive estrogen receptor with BC susceptibility in CC genotype.

CONCLUSION

The existence of a C-allele at miRNA 196a2(11614913) elevates women's BC susceptibility in Azeri ethnicity in Iran.

Polymorphism rs2682818 in miR-618 is associated with colorectal cancer susceptibility in a Han Chinese population

MicroRNAs (miRNAs), endogenous small noncoding RNAs (ncRNAs), play crucial roles in cancer development. Many studies have demonstrated that miRNAs can serve as diagnostic and therapeutic biomarkers for malignancies. Additionally, single nucleotide polymorphisms (SNPs) located in miRNA functional regions have been reported to be involved in cancer susceptibility. In this study, we investigated the associations between SNPs located in miRNA functional regions and colorectal cancer (CRC) susceptibility. We systematically screened all candidate miRNAs and their SNPs and then evaluated the relationships between the SNPs and CRC susceptibility in a Han Chinese population including 878 patients with CRC and 884 controls. Genotyping was performed by TaqMan assay. After comprehensively screening the miRNAs and SNPs, we elected to evaluate the association between SNP rs2682818 in miR‐618 and CRC susceptibility. We found that the AA and AC/AA genotypes of rs2682818 were associated with a decreased risk of CRC compared with the CC genotype (odds ratio (OR) = 0.54, 95% confidence interval (CI) = 0.37–0.79 for AA vs. CC in codominant model; OR = 0.82, 95% CI = 0.68–0.99 for AC/AA vs. CC in dominant model). However, we obtained no statically significant results in our subgroup analyses. SNP rs2682818 in miR‐618 has potential as a biomarker for individuals with high CRC susceptibility. Our findings need to be verified in studies including larger samples. Moreover, molecular functional studies of miR‐681 must be performed to confirm its relationship with CRC.

Investigating the association of rs2910164 with cancer predisposition in an Irish cohort

INTRODUCTION

MicroRNAs (miRNAs) are small noncoding RNA molecules that exert post-transcriptional effects on gene expression by binding with cis-regulatory regions in target messenger RNA (mRNA). Polymorphisms in genes encoding miRNAs or in miRNA-mRNA binding sites confer deleterious epigenetic effects on cancer risk. miR-146a has a role in inflammation and may have a role as a tumour suppressor. The polymorphism rs2910164 in the MIR146A gene encoding pre-miR-146a has been implicated in several inflammatory pathologies, including cancers of the breast and thyroid, although evidence for the associations has been conflicting in different populations. We aimed to further investigate the association of this variant with these two cancers in an Irish cohort.

METHODS

The study group comprised patients with breast cancer (BC), patients with differentiated thyroid cancer (DTC) and unaffected controls. Germline DNA was extracted from blood or from saliva collected using the DNA Genotek Oragene 575 collection kit, using crystallisation precipitation, and genotyped using TaqMan-based PCR. Data were analysed using SPSS, v22.

RESULTS

The total study group included 1516 participants. This comprised 1386 Irish participants; 724 unaffected individuals (controls), 523 patients with breast cancer (BC), 136 patients with differentiated thyroid cancer (DTC) and three patients with dual primary breast and thyroid cancer. An additional cohort of 130 patients with DTC from the South of France was also genotyped for the variant. The variant was detected with a minor allele frequency (MAF) of 0.19 in controls, 0.22 in BC and 0.27 and 0.26 in DTC cases from Ireland and France, respectively. The variant was not significantly associated with BC (per allele odds ratio = 1.20 (0.98-1.46), P  = 0.07), but was associated with DTC in Irish patients (per allele OR = 1.59 (1.18-2.14), P = 0.002).

CONCLUSION

The rs2910164 variant in MIR146A is significantly associated with DTC, but is not significantly associated with BC in this cohort.

Association between Microrna 146a and Microrna 196a2 Genes Polymorphism and Breast Cancer Risk in North Indian Women

Background:

Micro RNAs (miRNAs) are small, noncoding RNA molecules. They can function as either oncogenes or tumor suppressor genes. Single nucleotide polymorphisms (SNP) present in the pre-miRNA region could affect the processing of miRNA and thus alter mature miRNA expression. The studies done so far had shown conflicting results regarding association of two common polymorphisms i.e.hsa-miR-146 rs2910164 and hsa-miR-196a2 rs11614913 with breast cancer. OBJECTIVE: In the study, we examined the hsa-miR-146 rs2910164 and hsa-miR-196a2 rs11614913 SNP association with breast cancer patients in north Indian women.

Materials and Methods:

This study included 100 breast cancer patients and 100 controls and was done over a period of two years. Genotypes of the hsa-miR-146 (rs2910164 G>C) and hsa-miR-196a2 (rs11614913 C>T) were identified by polymerase chain reaction – restriction length polymorphism (PCR-RFLP) technique in peripheral blood DNA samples.

Statistical analysis:

We assessed the strength of association of miRNA polymorphisms with breast cancer using Odds ratio (OR) along with 95% confidence intervals.

Results:

Heterozygous genotypes of hsa-miR-196a2 rs11614913 and combined hsa-miR-146 rs2910164 & hsa-miR-196a2 polymorphism were associated with significantly increased risk of breast cancer (OR-1.7, 95% CI–1.00-3.18) and (OR-1.9, 95% CI-0.85-4.46) respectively.

Conclusion:

Our study suggests that rs2910164 GC and rs11614913 CT genotypes may contribute to breast cancer susceptibility in north Indian women.

Meta-analysis of the association between three microRNA polymorphisms and breast cancer susceptibility

Single nucleotide polymorphisms (SNPs) in three microRNAs (miRNAs), rs2910164 in miR-146a, rs11614913 in miR-196a2, and rs3746444 in miR-499, have been associated with breast cancer (BC) susceptibility, but the evidence is conflicting. To obtain a more robust assessment of the association between these miRNA variants and BC risk, we carried out a meta-analysis through systematic literature retrieval from the PubMed and Embase databases. A total of 9 case-control studies on rs2910164, 12 on rs11614913, and 7 on rs3746444 were included. Pooled odds ratios and 95% confidence intervals were used to evaluate associations with BC risk. Overall analysis showed that rs2910164 was not associated with BC susceptibility in any genetic model, whereas rs11614913 was associated with a decreased risk in both the allelic contrast and recessive models, and rs3746444 imparted an increased risk in all genetic models. Stratified analyses showed that rs11614913 may decrease the risk of BC in the heterozygote model in Asians, and in all genetic models, except the heterozygote model, when the sample size is ≥ 500. Subgroup analysis indicated that rs3746444 was associated with increased risk of BC in Asians, but not Caucasians, at all sample sizes. This meta-analysis suggests that rs11614913 in miR-196a2 may decrease the risk of BC, while rs3746444 in miR-499 may increase it, especially in Asians when the sample size is large. We propose that rs11614913(C > T) and rs3746444 (A > G) may be useful biomarkers predictive of BC risk.

A Variant in the Precursor of MicroRNA-146a is Responsible for Development of Erectile Dysfunction in Patients with Chronic Prostatitis via Targeting NOS1

Background

The morbidity of erectile dysfunction (ED) has been found to be substantially increased in patients with chronic prostatitis (CP). Accumulating evidence shows that single-nucleotide polymorphism (SNP) located in pre-miRNA or mature microRNA may affect the processing of microRNA (miRNA) and alter the expression of the miRNA, as well as its target gene. In this study we investigated the association between rs2910164 G/C polymorphism and risk of ED in patients with CP, as well as the underlying molecular mechanism.

Material/Methods

Computational analysis was used to search for the target of miR-146a, and the luciferase reporter assay system was used to validate NOS1 to be the target gene of miR-146a. We also treated PC-3 cells with miR-146a mimics/inhibitors to verify the negative regulatory relationship between miR-146a and NOS1, and real-time PCR and Western blot analysis were used to estimate the expression of the NOS1 mRNA and miR-146a.

Results

The binding site of miR-146a was found to be located within the 3′-UTR of the NOS1 by searching an online miRNA database (www.mirdb.org), and luciferase reporter assay was done to confirm that NOS1 is a direct target gene of miR-146a. We also found that mRNA and protein expression level of NOS1 in PC-3 cells treated with miR-146a mimics and NOS1 siRNA was substantially down-regulated compared with scramble control, while cells treated with miR-146a inhibitors showed increased expression of NOS1. In addition, 705 people were recruited for our research – 342 CP patients with ED and 363 CP patients without ED – and we found that the presence of minor allele of rs2910164 polymorphism is significantly associated with reduced risk of ED in patients with CP.

Conclusions

The findings indicate a decreased risk of ED in patients with CP who are carriers of miR-146a rs2910164 C allele, and this association might be due to its ability to compromise the expression of miR-146a, and thereby increase the expression of its target gene, NOS1.

MicroRNA-124 rs531564 Polymorphism and Cancer Risk: A Meta-analysis

Several studies reported there was a polymorphism (rs531564 C > G) in miR-124 gene. To investigate the MiR-124 rs531564 polymorphism and cancer risk. We conducted a literature search of the Medline, Embase and Wangfang Medicine databases to identify all relevant studies for this meta-analysis. We determined that the miR-124 rs531564 polymorphism was significantly associated with decreased risks of cancers in the allelic model (G vs C, OR=0.71, 95% CI=0.53-0.94, P=0.02), homozygote model (GG vs CC, OR=0.42, 95% CI=0.26-0.66, P=0.0002), dominant model (GG/GC vs CC, OR=0.71, 95% CI=0.51-0.98, P=0.04) and recessive model (GG vs GC/CC, OR=0.43, 95% CI=0.27-0.69, P=0.0004). In an analysis stratified by cervical cancer group, significant associations were observed in the allelic model (G vs C, OR=0.46, 95% CI=0.32-0.66, P<0.0001), and dominant model (GG/GC vs CC, OR=0.45, 95% CI=0.3-0.66, P<0.0001). Subgroup analysis also revealed a decreased risk for esophageal squamous cell carcinoma in the homozygote model (GG vs CC, OR=0.45, 95% CI=0.27-0.75, P=0.002) and recessive model (GG vs GC/CC, OR=0.46, 95% CI=0.28-0.75, P=0.002). This meta-analysis suggests that the miR-124 rs531564 C > G polymorphism is an important risk factor for cancers among the Chinese population.

A single nucleotide polymorphism in hsa‑miR‑146a is responsible for the development of bronchial hyperresponsiveness in response to intubation during general anesthesia

Bronchial hyperresponsiveness (BHR) is the most common clinical manifestation identified in asthmatic patients, and intubation is the major factor that stimulates the airway of patients receiving general anesthetic. In the present study, nitric oxide synthase 1 (NOS1) was identified as a target gene of micro (mi)R‑146a using in silico analysis and luciferase assay. Furthermore, the regulatory role of miR‑146a was demonstrated by the observation that the NOS1 expression level in pulmonary artery smooth muscle cells (PASMCs) transfected with miR‑146a mimics was significantly downregulated and the NOS1 expression level in PASMCs transfected with miR‑146a inhibitors was significantly upregulated. Additionally, it was identified that a polymorphism in pri‑miR‑146 interfered with mature processing and reduced the quantity of mature miRNA. To assess the association between the polymorphism and the development of BHR, 563 patients with basic pulmonary diseases, such as asthma, emphysema or bronchitis were enrolled in the present study. Each participant received a general anesthetic and the development of BHR was evaluated. The miR‑146a rs2910164 polymorphism CC genotype was identified to be significantly associated with a decreased risk of BHR in response to intubation when compared with the GG or GC genotype (odds ratio, 0.38; confidence interval, 0.18‑0.78). These findings indicate that the miR‑146a rs2910164 polymorphism is associated with a decrease risk of BHR, and the CC genotype increased the level of NOS1 expression, which was physiologically inhibited by wild‑type miR‑146a.

The Associations of Single Nucleotide Polymorphisms in miR196a2, miR-499, and miR-608 With Breast Cancer Susceptibility: A STROBE-Compliant Observational Study

MicroRNAs (miRNAs) play an important role as regulators of tumor suppressors and oncogenes in cancer-related processes. Single nucleotide polymorphisms (SNPs) in miRNAs have been shown to be relevant to various different cancers, including breast cancer (BC). The aim of this study was to estimate the associations between miRNA-related gene polymorphisms (miR-196a2, miR-499, and miR-608) and the risk of BC in a Chinese population. Gene polymorphisms were analyzed in 1143 subjects (controls = 583; BC = 560). The 3 SNPs were genotyped using the Sequenom Mass-ARRAY platform. The associations between the SNP frequencies and BC were assessed by computing odds ratios (ORs) and 95% confidence intervals (95% CIs), as well as by applying Chi-square tests. The miR-196a2 (rs11614913) T allele was associated with a decreased risk of BC based on results from dominant (OR = 0.67, 95% CI = 0.52-0.86), recessive (OR = 0.65, 95% CI = 0.48-0.86), and allele models (OR = 0.73, 95% CI = 0.62-0.86). In contrast, the miR-499 (rs3746444) AG/GG genotypes were associated with an increased risk of BC (OR = 1.45, 95% CI = 1.10-1.91), and miR-608 (rs4919510) was not significantly associated with BC risk. Our study suggested that the polymorphisms of rs11614913 and rs3746444 may be associated with BC risk in Chinese individuals.

Effect of a functional polymorphism in the pre-miR-146a gene on the risk and prognosis of renal cell carcinoma

MicroRNAs (miRNAs) are non-coding RNAs that function as regulators of tumor suppressors and oncogenes. A G>C polymorphism (rs2910164) in the miR‑146a precursor sequence leads to a functional change associated with a risk for various types of malignancy. The role of this single nucleotide polymorphism in the pathogenesis of renal cell carcinoma (RCC) has not yet been examined. The present study evaluated the association between rs2910164 genotypes and the risk and prognosis of RCC in a population comprised of 421 RCC cases and 432 controls. Unconditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) for rs2910164 genotypes according to case status. Cox proportional hazards regression modeling was used to estimate hazards ratios and 95% CIs according to the genotypes among the RCC patients. It was found that the rs2910164 GG and GC genotypes were associated with an increased risk of RCC only in senior subjects (>57‑years old; adjusted OR=1.59, 95% CI=1.04‑2.43). Furthermore, the GC and GG genotypes were associated with a poorer survival rate among patients with RCC compared with the CC genotype (P=0.002). In conclusion, the observed association between the GG and GC genotype and poorer survival rate of RCC was at least partially mediated by the decreased expression of miR-146a.

Effect of a single nucleotide polymorphism in miR-146a on COX-2 protein expression and lung function in smokers with chronic obstructive pulmonary disease

OBJECTIVE

To evaluate the effect of a single nucleotide polymorphism (rs2910164) in the miR-146a precursor on the expression level of miR-146a, cyclooxygenase-2 (COX2), and production of prostaglandin E2 (PGE2) in lung tissue harvested from smokers with chronic obstructive pulmonary disease, as well as the lung function and disease stages from the same patient population.

METHODS AND RESULTS

One-hundred and sixty-eight smokers with diagnosed chronic obstructive pulmonary disease were recruited. The patients were genotyped for rs2910164 polymorphism using Sanger sequencing, and their lung function/disease stages were evaluated following Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria. Meanwhile, messenger ribonucleic acid and protein expression levels of miR-146a and COX2 as well as PGE2 production were determined in 66 lung tissue samples collected in the patients who received surgical treatment. We confirmed that COX2 is a validated target of miR-146a in human fibroblast cells, and identified the differential expression patterns of miR-146a and COX2 in each rs2910164 genotype group. We observed a significant association between rs2910164 in miR-146a and the levels of either COX2 or PGE2 using real-time polymerase chain reaction and Western blot. Consistently, we were able to demonstrate that the rs2910164 single nucleotide polymorphism has a functional effect on the baseline lung function in the study population.

CONCLUSION

In the present study, the rs2910164 CC and GC genotype was found to be associated with an improved lung function and milder disease stages, at least partially, mediated by its ability to increase in COX2 expression and PGE2 production.

Critical analysis of the potential for microRNA biomarkers in breast cancer management

Breast cancer is a complex and heterogeneous disease. Signaling by estrogen receptor (ER), progesterone receptor (PR), and/or human EGF-like receptor 2 (HER2) is a main driver in the development and progression of a large majority of breast tumors. Molecular characterization of primary tumors has identified major subtypes that correlate with ER/PR/HER2 status, and also subgroup divisions that indicate other molecular and cellular features of the tumors. While some of these research findings have been incorporated into clinical practice, several challenges remain to improve breast cancer management and patient survival, for which the integration of novel biomarkers into current practice should be beneficial. microRNAs (miRNAs) are a class of short non-coding regulatory RNAs with an etiological contribution to breast carcinogenesis. miRNA-based diagnostic and therapeutic applications are rapidly emerging as novel potential approaches to manage and treat breast cancer. Rapid technological development enables specific and sensitive detection of individual miRNAs or the entire miRNome in tissues, blood, and other biological specimens from breast cancer patients. This review focuses on recent miRNA research and its potential to address unmet clinical needs and challenges. The four sections presented discuss miRNA findings in the context of the following clinical challenges: biomarkers for early detection; prognostic and predictive biomarkers for treatment decisions using targeted therapies against ER and HER2; diagnostic and prognostic biomarkers for subgrouping of triple-negative breast cancer, for which there are currently no targeted therapies; and biomarkers for monitoring and characterization of metastatic breast cancer. The review concludes with a critical analysis of the current state of miRNA breast cancer research and the need for further studies using large patient cohorts under well-controlled conditions before considering the clinical implementation of miRNA biomarkers.

Revealing editing and SNPs of microRNAs in colon tissues by analyzing high-throughput sequencing profiles of small RNAs

Background

Editing and mutations in microRNAs (miRNAs) can change the stability of pre-miRNAs and/or complementarities between miRNAs and their targets. Small RNA (sRNA) high-throughput sequencing (HTS) profiles contain miRNAs that are originated from mutated DNAs or are edited during their biogenesis procedures. It is largely unknown whether miRNAs are edited in colon tissues since existing studies mainly focused their attention on the editing of miRNAs in brain tissues.

Results

Through comprehensive analysis of four high-throughput sequencing profiles of normal and cancerous colon tissues, we identified 548 editing and/or SNPs in miRNAs that are significant in at least one of the sequencing profiles used. Our results show that the most abundant editing events of miRNAs in colon tissues are 3'-A and 3'-U. In addition to four known A-to-I editing sites previously reported in brain tissues, four novel A-to-I editing sites are also identified in colon tissues.

Conclusions

This suggests that A-to-I editing of miRNAs potentially is a commonly existing mechanism in different tissues to diversify the possible functional roles of miRNAs, but only a small portion of different miRNAs are edited by the A-to-I mechanism at a significant level. Our results suggest that there are other types of editing in miRNAs through unknown mechanisms. Furthermore, several SNPs in miRNAs are also identified.

microRNAs: a new class of breast cancer biomarkers

MicroRNAs (miRNAs) are regulatory molecules known to be aberrantly expressed in cancer and contribute to numerous aspects of tumor biology including the initiation, growth and spread of the tumor. With such diverse roles, it is becoming apparent that some may also provide valuable information which may be of use in a clinical setting, demonstrating the potential to act as both screening tools for the stratification of high-risk patients, while informing the treatment decision-making process. There is mounting evidence to suggest that some miRNAs may even provide assistance in the diagnosis of patients with breast cancer. In addition, miRNAs may themselves be considered therapeutic targets, with inhibition or reintroduction of a particular miRNA capable of inducing a response in vivo. This review focuses on miRNAs that have prognostic, diagnostic or predictive potential in breast cancer as well as the possible challenges in the translation of such observations to the clinic.

MiR-146a rs2910164 G/C polymorphism and gastric cancer susceptibility: a meta-analysis

BACKGROUND

Evidence has shown that single nucleotide polymorphism located in pre-miRNA or mature microRNA may modify various biological processes and affect the processing of carcinogenesis. Published results about the association between miR-146a rs2910164 G/C polymorphism and human gastric cancer susceptibility are inconclusive. The aim of this study was to acquire a more precise effect of the association between the miR-146a rs2910164 polymorphism and gastric risk by meta-analysis.

METHODS

Eligible genetic association studies were searched from PubMed, Web of Knowledge and Chinese Biomedicine Database on human subject. Quantitative data synthesis was conducted for the associations of miR-146a rs2910164 G/C polymorphism with susceptibility to gastric cancer.

RESULTS

Nine eligible studies that included a total of 3,885 gastric cancer patients and 5,396 controls were identified in the present meta-analysis. The overall OR indicated a potential association between rs2910164 polymorphism and GC but the effect was not statistically significant (GG vs.

CG/CC

OR = 1.076, 95% CI 0.925-1.251, P = 0.342). When stratifying for population, the result showed that miR-146a rs2910164 GG genotype was associated with increased gastric cancer risk among Chinese in recessive model (GG vs.

CG/CC

OR = 1.171, 95% CI 1.050-1.306, P = 0.005). Besides, no significant difference was found in gender, smoking, location, metastasis of lymph node and Laurèn's classification.

CONCLUSIONS

The present meta-analysis suggests an increased risk between miR-146a rs2910164 GG genotype and gastric cancer susceptibility in Chinese based on published literatures.

hsa-mir-499 rs3746444 gene polymorphism is associated with susceptibility to breast cancer in an Iranian population

AIM

Our study aimed to evaluate the possible association between four miRNA polymorphisms, hsa-miR-146a (rs2910164 G>C), hsa-miR-499 (rs3746444 T>C) and hsa-miRNA-196a2 (rs11614913 C>T and rs185070757 T>G), and susceptibility to breast cancer in an Iranian population.

MATERIALS & METHODS

In this case-control study we enrolled 236 patients with breast cancer and 203 healthy individuals. Tetra primer amplification refractory mutation system PCR was applied for genotyping the four miRNA SNPs.

RESULTS

Our study indicated that the hsa-mir-499 rs3746444 CC homozygote increased the risk of breast cancer in the dominant (odds ratio [OR]: 2.42; 95% CI: 1.43-4.09; p = 0.001; CC vs TT) and recessive (OR: 2.48; 95% CI: 1.49-4.13; p = 0.004; CC vs TT+TC) inheritance models tested. In addition, the rs3746444 C allele increased the risk of breast cancer (OR: 1.71; 95% CI: 1.27-2.29; p = 0.0004) in comparison with the T allele. However, distribution of the rs2910164 G>C, rs11614913 C>T and rs185070757 T>G genotypes was not statistically different between cases and controls (p > 0.05).

CONCLUSION

Our findings demonstrated that the hsa-mir-499 rs3746444 polymorphism is associated with higher risk of developing breast cancer in our population.

A single-nucleotide polymorphism of miR-146a and psoriasis: an association and functional study

Epidermal growth factor receptor (EGFR), which is overexpressed in psoriatic lesions, has been proven to contribute to the hyperproliferation of keratinocytes in psoriasis. Single nucleotide polymorphisms (SNPs) involved in miRNAs that can regulate the expression of EGFR could potentially influence the development of psoriasis. The present study investigated the association between a functional SNP of rs2910164 in miR-146a and the risk of psoriasis in the Chinese Han population. A total of 521 Han Chinese patients with psoriasis and 582 healthy controls were recruited in this study. The miR-146a rs2910164 SNP was genotyped by polymerase chain reaction-restriction fragment length polymorphism. Overall, a significantly increased risk of psoriasis was associated with the rs2910164 miR-146a CG and GG genotypes (adjusted OR, 1.38; 95% CI, 1.06–1.80). Furthermore, the rs2910164G allele in miR-146a attenuated its inhibitory regulation on the expression of EGFR as well as the proliferation of human keratinocytes, and lowered the level of miR-146a in the psoriatic lesions. These findings indicate that the rs2910164G allele in miR-146a weakens its suppression on the proliferation of keratinocytes probably through the decreased inhibition of the target gene, EGFR, which may account for the increased risk of psoriasis in this study population.

High-resolution melting analysis reveals genetic polymorphisms in microRNAs confer hepatocellular carcinoma risk in Chinese patients

BACKGROUND

Although several single-nucleotide polymorphisms in microRNA (miRNA) genes have been associated with primary hepatocellular carcinoma, published findings regarding this relationship are inconsistent and inconclusive.

METHODS

The high-resolution melting (HRM) analysis was used to determine whether the occurrence of the SNPs of miR-146a C > G (rs2910164), miR-196a2 C > T (rs11614913), miR-301b A > G (rs384262), and miR-499 C > T (rs3746444) differs in frequency-matched 314 HCC patients and 407 controls by age and sex.

RESULTS

The groups' genotype distributions of miR-196a2 C > T and miR-499 C > T differed significantly (P < 0.01), both of them increased the risk of HCC in different dominant genetic models (P < 0.01); compared with individuals carrying one or neither of the unfavorable genotypes, individuals carrying both unfavorable genotypes (CT + CC) had a 3.11-fold higher HCC risk (95% confidence interval (CI), 1.89-5.09; P = 7.18 × 10-6). Moreover, the allele frequency of miR-499 C > T was significantly different between the two groups, and the HCC risk of carriers of the C allele was higher than that of carriers of the T allele (odds ratio, 1.53; 95% CI, 1.15-2.03; P = 0.003). Further, we found that the activated partial thromboplastin time (APTT) in HCC patients with miR-196a2 CC genotype was longer than patients with TT genotypes (P < 0.05), and HCC patients with miR-499 C allele had higher serum levels of direct bilirubin, globulin, γ-glutamyltranspeptidase, alkaline phosphatase, and lower serum cholinesterase (P < 0.05).

CONCLUSIONS

Our findings suggest that the SNPs in miR-196a2 C > T and miR-499 C > T confer HCC risk and that affect the clinical laboratory characteristics of HCC patients.

Association study of two inflammation-related polymorphisms with susceptibility to hepatocellular carcinoma: a meta-analysis

Background

Inflammation is a response of body tissues to injury or irritation. Small RNAs, such as miR-146a and miR-499, participate in various processes of tumorigenesis. A recent study indicates that inflammation and abnormal immune responses may promote malignant progression in cancer development, indicating that inflammation-related polymorphisms such as miR-146a rs2910164 and miR-499 rs3746444 are crucial. However, studies on the association of these two polymorphisms with hepatocellular carcinoma (HCC) are inconclusive and inconsistent. We aimed at accessing the combined result of reported studies and make a more precise estimate of the relationship.

Methods

Meta-analysis was performed on the associations between the miR-146a rs2910164 C > G and miR-499 rs3746444 T > C polymorphisms and hepatocellular carcinoma, using: allele contrast, dominant, and recessive models. A total of 12 studies(8 on miR-146a rs2910164 and 4 on miR-499 rs3746444) with three populations (Chinese, Korean, Turkish) were included in this study.

Results

Results show that both allele frequency and genotype distributions of miR-146a rs2910164 polymorphism are significantly associated with susceptibility to HCC (G versus C: OR = 1.153, 95% CI 1.083–1.228, P < 0.001; GC versus CC: OR = 1.165, 95% CI 1.054–1.286, P = 0.003; GG versus CC: OR = 1.361, 95% CI 1.192–1.553, P < 0.001; GG/GC versus CC: OR = 1.213, 95% CI 1.104–1.333, P < 0.001; GG versus GC/CC: OR = 1.210, 95% CI 1.080–1.356, P < 0.001). Our data suggest that people with G allele have a higher susceptibility to HCC as compared to those with C allele. However, meta-analysis failed to detect associations between miR-499 rs3746444 and HCC risk under each genetic model tested. Subgroup analysis showed that Chinese population with CC genotype are more vulnerable to HCC (OR = 2.171, 95% CI = 1.149–4.104, P = 0.017) than those with TT genotype.

Conclusions

We conclude that rs2910164 in miR-146a may confer susceptibility to HCC, especially in the Chinese population. No significant association was found between miR-499 rs3746444 and HCC, but subgroup study showed that subjects with CC genotype are more vulnerable to HCC than TT genotype in the Chinese population.

Association between hsa-miR-34b/c rs4938723 T > C promoter polymorphism and cancer risk: a meta-analysis based on 6,036 cases and 6,204 controls

OBJECTIVE

Emerging evidence shows that microRNAs (miRNAs) function as tumor suppressors or oncogenes in human carcinogenesis. A single nucleotide polymorphism (SNP) located in the pri-miRNA promoter may affect the processing and expression of mature miRNA. However, previous studies showed conflicting results regarding the association of hsa-miR-34b/c rs4938723 T > C promoter polymorphism with cancer. Therefore, we conducted a meta-analysis to determine the association of polymorphism with cancer risk.

METHODS

A computerized search of PubMed, Web of Science, and Chinese National Knowledge Infrastructure (CNKI) for publications on hsa-miR-34b/c rs4938723 T > C promoter polymorphism and cancer risk was performed and the genotype data were analyzed in a meta-analysis. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated to assess the association. Test of heterogeneity, cumulative meta-analysis, sensitivity analysis and assessment of bias were performed in our meta-analysis by STATA software 12.0.

RESULTS

There was no significant association between hsa-miR-34b/c rs4938723 polymorphism and overall cancer risk in the comparison models. Moreover, subgroup analysis revealed that the variant CT (OR =1.19, 95% CI: 1.03-1.37) and CC/CT (OR =1.18, 95% CI: 1.03-2.35) genotypes were associated with an increased risk of hepatocellular carcinoma (HCC) compared with wild-type TT genotype. However, a decreased risk of colorectal cancer (CRC) was found in the genetic model of CC/TT (OR =0.66, 95% CI: 0.47-0.92) and CC/CTTT (OR =0.67, 95% CI: 0.49-0.93).

CONCLUSIONS

The results suggest that hsa-miR-34b/c rs4938723 polymorphism may play an opposite role in different types of cancer based on current studies, which is the main origin of heterogeneity in this meta-analysis. Further large-scale studies and functional studies between this polymorphism and cancer risk are warranted.

miR-146a G>C polymorphisms and risk of hepatocellular carcinoma in a Chinese population

MicroRNAs (miRNAs) are thought to have a role in cancer development. We investigated the association among miR-146a G>C genetic variations, hepatitis B (HBV), and C (HCV) infection, and risk of hepatocellular carcinoma (HCC). Unconditional logistical regression analysis suggested that the miR-146a GG genotype and G allele carried a 2.10- (95 % confidence interval (CI)=1.03-4.37) and 1.42-fold (95 % CI=1.07-1.92) increased HCC risk, respectively. HBV-positive subjects carrying the miR-146a GG genotype (odds ratio (OR)=2.95, 95 % CI=1.31-6.81) and G allele (OR=1.65, 95 % CI=1.15-2.58) had an increased risk of HCC. However, the miR-146a GG genotype and G allele did not carry a significantly enhanced risk of HCC in either hepatitis-negative or HCV-infected subjects. miR-146a G>C polymorphisms appear to influence susceptibility to HCC, especially in HBV-infected patients.

Positive association between miR-499A>G and hepatocellular carcinoma risk in a Chinese population

A case-control study of the association of miR-499A>G rs3746444 with risk of hepatocellular carcinoma (HCC)was conducted. Patients with HCC and healthy control subjects were recruited for genotyping of miR- 499A>G using duplex polymerase-chain-reaction with confronting-two-pair primer(PCR-RFLP) analysis. The MiR-499 GG genotype was associated with a decreased risk of HCC as compared with the miR-499 AA genotype (adjusted OR=0.74, 95%CI=0.24-0.96). Similarly, the GG genotype showed a 0.45-fold decreased HCC risk in a recessive model. The MiR-499 G allele was significantly associated with decreased risk of HCC among patients infected with HBV in a dominant model (OR=0.09, 95%CI= 0.02-0.29). In conclusion, the MiR-499A>G rs3746444 polymorphism is associated with HCC risk in the Chinese population, and may be useful predictive marker for CAD susceptibility.

Association between microRNA polymorphisms and cancer risk based on the findings of 66 case-control studies

MicroRNAs (miRNAs) are small non-coding RNA molecules, which participate in diverse biological processes and may regulate tumor suppressor genes or oncogenes. Single nucleotide polymorphisms (SNPs) in miRNA may contribute to diverse functional consequences, including cancer development, by altering miRNA expression. Numerous studies have shown the association between miRNA SNPs and cancer risk; however, the results are generally debatable and inconclusive, mainly due to limited statistical power. To assess the relationship between the five most common SNPs (miR-146a rs2910164, miR-196a2 rs11614913, miR-499 rs3746444, miR-149 rs2292832, and miR-27a rs895919) and the risk cancer development, we performed a meta-analysis of 66 published case-control studies. Crude odds ratios at 95% confidence intervals were used to investigate the strength of the association. No association was observed between rs2910164 and cancer risk in the overall group. However, in stratified analysis, we found that either the rs2910164 C allele or the CC genotype was protective against bladder cancer, prostate cancer, cervical cancer, and colorectal cancer, whereas it was a risk factor for papillary thyroid carcinoma and squamous cell carcinoma of the head and neck (SCCHN). Further, rs11614913 was found to be significantly associated with decreased cancer risk, in particular, for bladder cancer, gastric cancer, and SCCHN. For miR-499, a significant association was found between the rs3746444 polymorphism and cancer risk in pooled analysis. In subgroup analysis, similar results were mainly observed for breast cancer. Finally, no association was found between rs2292832 and rs895919 polymorphisms and cancer risk in the overall group and in stratified analysis. In summary, miR-196a2 rs11614913, miR-146a rs2910164, and miR-499 rs3746444 are risk factors for cancer development, whereas mir-149 rs2292832 and miR-27a rs895919 are not associated with cancer risk.

miRNA dysregulation in breast cancer

miRNAs have emerged, in the last decade, as key players in the carcinogenic process, with many candidates identified as playing important roles in many aspects of tumor development, growth, metastasis, and drug resistance. More recently, polymorphisms in miRNAs themselves or in their binding sites in target genes have been identified to incur increased risk of breast cancer in certain populations. In addition, epigenetic regulation and differential expression of processing enzymes has been shown to contribute to the aberrant expression of miRNAs in breast cancer. This review focuses on the area of miRNA dysregulation in breast cancer through both genetic and epigenetic mechanisms, and the impact of this dysregulation on breast cancer risk and resistance to therapies.

A genetic polymorphism in pre-miR-27a confers clinical outcome of non-small cell lung cancer in a Chinese population

Background

Recent evidence indicates that microRNAs (miRNAs) can function as tumor suppressors and oncogenes. Single nucleotide polymorphisms (SNPs) at miRNA genes can influence the maturation of miRNAs or miRNA-mediated transcriptional regulation. Our objective was to investigate the association of SNPs in deregulated miRNAs with clinical outcome in patients with non-small cell lung cancer (NSCLC) in a Chinese population.

Methods

Deregulated miRNAs in NSCLC and their SNPs were identified through public databases. A single SNP, rs895819 in pre-miR-27a, was found suitable for selection. TaqMan assays were performed for genotyping and to assess the effect on the overall survival (OS) and chemotherapy response in 576 NSCLC patients.

Results

Log-rank test and Cox regression analysis indicated that the G allele of rs895819 was associated with shorter survival and increased risk of death in NSCLC [dominant model: 22.0 vs. 46.0 months, P<0.001; adjusted hazard ratio (HR) = 1.71, 95% confidential interval (CI): 1.12–2.26]. Further stepwise regression analysis suggested that this SNP was an independently unfavorable factor for the prognosis of NSCLC and the effect remained significant in subgroup analysis stratified by clinical parameters and treatment status. Moreover, multivariate logistic regression analysis showed that the subjects with AG/GG genotypes of rs895819 had significantly decreased response rate to platinum-based chemotherapy compared to those with the AA genotype.

Conclusion

Our results suggest that the pre-miR-27a rs895819 polymorphism may influence NSCLC patients’ clinical outcome. Further large sample studies should be used to validate our findings.

Comprehensive analysis of single nucleotide polymorphisms in human microRNAs

MicroRNAs (miRNAs) are endogenous small non-coding RNAs that repress their targets at post transcriptional level. Single Nucleotide Polymorphisms (SNPs) in miRNAs can lead to severe defects to the functions of miRNAs and might result in diseases. Although several studies have tried to identify the SNPs in human miRNA genes or only in the mature miRNAs, there are only limited endeavors to explain the distribution of SNPs in these important genes. After a genome-wide scan for SNPs in human miRNAs, we totally identified 1899 SNPs in 961 out of the 1527 reported miRNA precursors of human, which is the most complete list of SNPs in human miRNAs to date. More importantly, to explain the distributions of SNPs existed in human miRNAs, we comprehensively and systematically analyzed the identified SNPs in miRNAs from several aspects. Our results suggest that conservation, genomic context, secondary structure, and functional importance of human miRNAs affect the accumulations of SNPs in these genes. Our results also show that the number of SNPs with significantly different frequencies among various populations in the HapMap and 1000 Genome Project data are consistent with the geographical distributions of these populations. These analyses provide a better insight of SNPs in human miRNAs and the spreading of the SNPs in miRNAs in different populations.

Evaluation of common genetic variants in pre-microRNA in susceptibility and prognosis of esophageal cancer

Genetic variants in micro-RNAs (miRNA) have been shown to affect progression, diagnosis, and prognosis of various malignancies; however, their role in esophageal squamous cell carcinoma (ESCC) susceptibility is controversial. Therefore, we aimed to determine role of common genetic variants in cancer related pre-miRNA in susceptibility and survival outcome of north Indian ESCC patients. We genotyped four common polymorphisms in pre-miRNA: mir-196a-2C>T, mir-146aG>C, mir-499T>C, and mir-423C>A in 289 incident ESCC cases (including 153 follow-up cases) and 309 controls using PCR/PCR RFLP-based methods. Binary logistic regression was applied for risk estimation, while Kaplan-Meier and Cox Regression tests were performed for survival analysis. We observed that none of the pre-miRNA genetic variants were associated with ESCC or its clinical phenotypes independently, however, combined risk genotypes of four pre-miRNA polymorphisms increased risk of ESCC in dose-response manner (Ptrend = 0.011). Specifically, patients with 2-4 risk genotypes of pre-miRNA polymorphisms had 1.4-fold higher risk of ESCC compared to patients with 0-1 risk genotypes (OR = 1.43, 95% CI = 1.02-1.09, P-value = 0.037). The risk was more pronounced in ESCC cases with upper-third esophageal tumors. Moreover, cumulative but not independent effect of risk genotypes of pre-miRNA polymorphisms was observed on survival outcome of ESCC patients. Cases with 2-4 risk genotypes had significantly lower median survival (11.60 vs. 30.2 months) and 2.3-fold greater hazard of death compared to patients with 0-1 risk genotypes. In conclusion, the four studied common pre-miRNA polymorphisms cumulatively affect susceptibility and survival of ESCC patients in north Indian population. © 2012 Wiley Periodicals, Inc.

A genetic variant in pre-miR-27a is associated with a reduced breast cancer risk in younger Chinese population

Accumulating evidence has indicated that single nucleotide polymorphisms (SNPs) in miRNA precursors may have an effect on miRNA expression levels. Recently, an important A to G transition SNP in pre-mir-27a (rs895819) was identified. Previous studies have investigated the role of rs895819 in cancer risk, but the results remain contradictory, rather than conclusive. The present study aimed to evaluate the association of rs895819 with sporadic breast cancer susceptibility, clinicopathological characteristics and prognosis. We first analyzed the influence of rs895819 on the miR-27a expression level and determined that miR-27a expression was significantly lower in samples with the AG/GG genotype compared to samples with the AA genotype (p=0.022). Further investigation revealed that subjects with the G allele exhibited a significantly decreased risk of breast cancer relative to subjects carrying the A allele among the younger population (adjusted OR=0.628, 95% confidence interval 0.410-0.961; p=0.032). Moreover, significant associations between the presence of rs895819 and the histological grade and estrogen status of breast cancers were observed among the older group. However, the SNP did not influence the survival rate of patients with breast cancer. In conclusion, our results suggest that the SNP rs895819 may serve as a risk factor for breast cancer in younger Chinese populations; however, larger population-based studies are needed to validate these findings.

Genetic variants in microRNAs and breast cancer risk in African American and European American women

MicroRNAs (miRNAs) are an integral part of the post-transcriptional machinery of gene expression and have been implicated in the carcinogenic cascade. Single nucleotide polymorphisms (SNPs) in miRNAs and risk of breast cancer have been evaluated in populations of European or Asian ancestry, but not among women of African ancestry. Here we examined 145 SNPs in six miRNA processing genes and in 78 miRNAs which target genes known to be important in breast cancer among 906 African American (AA) and 653 European American (EA) cases and controls enrolled in the Women's Circle of Health Study. Allele frequencies of most SNPs (87 %) differed significantly by race. We found a number of SNPs in miRNAs and processing genes in association with breast cancer overall or stratified by estrogen receptor (ER) status. Several associations were significantly different by race, with none of the associations being significant in both races. Using a polygenic risk score to combine the effects of multiple SNPs, we found significant associations with the score in each subgroup analysis. For ER-positive cancer, each unit increment of the risk score was associated with a 51 % increased risk in AAs (OR = 1.51, 95 % CI = 1.30-1.74, p = 3.3 × 10(-8)) and a 73 % increased risk in EAs (OR = 1.73, 95 % CI = 1.45-2.06, p = 1.4 × 10(-9)). These data show, for the first time, that miRNA-related genetic variations may underlie the etiology of breast cancer in both populations of African and European ancestries. Future studies are needed to validate our findings and to explore the underlying mechanisms.

The associations of single nucleotide polymorphisms in miR-146a, miR-196a and miR-499 with breast cancer susceptibility

Background

Previous studies have investigated the association between single nucleotide polymorphisms (SNPs) located in microRNAs (miRNAs) and breast cancer susceptibility; however, because of their limited statistical power, many discrepancies are revealed in these studies. The meta-analysis presented here aimed to identify and characterize the roles of miRNA SNPs in breast cancer risk, and evaluate the associations of polymorphisms in miR-146a rs2910164, miR-196a rs11614913 and miR-499 rs3746444 with breast cancer susceptibility, respectively.

Methodology/Principal Findings

The PubMed and Embases databases were searched updated to 31^st December, 2012. The complete data of polymorphisms in miR-146a rs2910164, miR-196a rs11614913 and miR-499 rs3746444 from case-control studies for breast cancer were analyzed by odds ratios (ORs) with 95% confidence intervals (CIs) to reveal the associations of SNPs in miRNAs with breast cancer susceptibility. Totally, six studies for rs2910164 in miR-146a, involving 4225 cases and 4469 controls; eight studies for rs11614913 in miR-196a, involving 4110 cases and 5100 controls; and three studies of rs3746444 in miR-499, involving 2588 cases and 3260 controls, were investigated in the meta-analysis. The rs11614913 (TT+CT) genotype of miR-196a2 was revealed to be associated with a decreased breast cancer susceptibility compared with the CC genotypes (OR = 0.906, 95% CI: 0.825–0.995, P = 0.039); however, no significant associations were observed between rs2910164 in miR-146a (or rs3746444 in miR-499) and breast cancer susceptibility.

Conclusions

This meta-analysis demonstrates the compelling evidence that the rs11614913 CC genotype in miR-196a2 increases breast cancer risk, which provides useful information for the early diagnosis and prevention of breast cancer.

Association between genetic variants in pre-miRNA and colorectal cancer risk in a Chinese population

INTRODUCTION

Single-nucleotide polymorphisms (SNPs) in pre-miRNAs may alter microRNA expression levels or processing and then contribute to the susceptibility of cancer development. We hypothesized that SNPs in pre-miRNAs may be associated with the risk of colorectal cancer (CRC).

MATERIALS AND METHODS

We genotyped four common polymorphisms (i.e., rs11614913, rs3746444, rs2910164, and rs2292832) in pre-miRNAs of 353 CRC patients and 540 healthy controls to investigate the association between the SNPs and the risk of CRC using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay.

RESULTS

The rs11614913 CT, TT genotypes, and T allele were associated with an increased risk of CRC compared with the CC genotype and C allele (CT vs. CC: OR = 7.34, 95% CI 3.76-14.34; TT vs. CC: OR = 13.66, 95% CI 6.76-27.6; T vs. C: OR = 1.99, 95% CI 1.63-2.42, respectively). Interestingly, using the rs2910164 GG genotype as a reference, the rs2910164 GC genotype was associated with an increased risk of CRC (OR = 1.49, 95% CI 1.02-2.18), whereas the rs2910164 CC genotype was associated with a decreased risk of CRC (OR = 0.58, 95% CI 0.37-0.93). When compared with the rs2910164G allele, rs2910164 C allele was associated with a reduced risk of CRC (OR = 0.80, 95% CI 0.66-0.97, p = 0.02).

CONCLUSION

These findings suggest that rs11614913 and rs2910164 polymorphisms may be associated with the etiology of CRC.

Association study of genetic variants in miRNAs in patients with inflammatory bowel disease: preliminary results

BACKGROUND

Aberrant expression and structural alteration of miRNAs are considered to participate in inflammation and cancer development. It has been suggested that common single-nucleotide polymorphisms (SNPs) in miRNAs are associated with susceptibility to several human diseases.

METHODS

In the present preliminary study we evaluated the associations of two SNPs (rs2910164 and rs11614913 in miR-146a and miR-196a2, respectively) with the risk of inflammatory bowel disease (IBD) in a Greek population.

RESULTS

The rs2910164 and rs11614913 SNPs were genotyped in 242 patients with Crohn's disease (CD), 210 patients with ulcerative colitis (UC) and 300 healthy individuals. No statistically significant differences were found in the genotype or allele distributions of the rs2910164 SNP among UC and control subjects. However, significant differences were found in the genotype or allele distributions of the rs2910164 polymorphism among CD and control subjects (P < 0.0001 and P < 0.0001, respectively). Concerning the rs11614913, no statistically significant differences were found in the genotype or allele distributions among CD and control patients, whereas TT genotype and T allele seem to have a protective role against UC (P = 0.017 and P = 0.007, respectively). The presence of rs2910164 and rs11614913 SNPs did not influence disease phenotype.

CONCLUSIONS

Our results demonstrate that the rs2910164 polymorphism has a major role in genetic susceptibility to CD but not to UC, since the rs11614913 polymorphism had a protective role against UC, at least in the population studied here. Independent studies are needed to validate our findings in larger series and in patients of different ethnic origins.

A functional polymorphism in the miR-146a gene is associated with the risk of childhood acute lymphoblastic leukemia: a preliminary report

Growing evidence showed that microRNAs (miRs) are involved in normal hematopoiesis and the pathogenesis of several hematological malignancies. Genetic variations or mutations occurring in the miR gene region may affect the property of miRs through altering miR expression and/or maturation. The aim of the present study was to evaluate the possible relationship between two miRs polymorphisms, hsa-miR-146a (rs2910164 G>C) and hsa-miR-499 (rs3746444 T>C), and the susceptibility to childhood acute lymphoblastic leukemia (ALL) in a sample of Iranian population. This case-control study was performed on 75 children diagnosed with ALL and 115 age- and sex-matched children with no history of cancer of any type (as the control group). Tetra-primer amplification refractory mutation system-polymerase chain reaction was applied for genotyping the variants. We found that the rs2910164 G>C variant of hsa-miR-146a significantly increased the risk of ALL (CC vs. GG, OR = 4.24, 95% CI = 1.52-11.87, P = 0.006; GC vs. GG, OR = 3.55, 95% CI = 1.41-8.93, P = 0.007; C vs. T, OR = 1.73, 95% CI = 1.13-2.67, P = 0.012). With respect to hsa-miR-499 rs3746444 T/C, no significant difference in allele and genotype frequencies of the rs3746444 variant between ALL patients and controls was observed. Our results for the first time demonstrated that the miR-146a rs2910164, but not miR-499 rs3746444 variant, was associated with increased risk for developing pediatrics ALL in an Iranian population.

A functional polymorphism rs11614913 in microRNA-196a2 is associated with an increased risk of colorectal cancer although not with tumor stage and grade

A C/T polymorphism (rs11614913) was identified in the microRNA (miRNA) 196a2 (miR-196a2) gene and was implicated in the susceptibility to cancer. Numerous studies have investigated its association with the risk of colorectal cancer (CRC). However, the results were inconsistent and inconclusive. The present meta-analysis was conducted based on the results of six published case-control studies comprising 1,754 cases and 2,430 controls (up to November, 2012). Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for the allelic and genotypic comparisons following the co-dominant, dominant and recessive genetic models. The Chi-square-based Q-test was used to assess heterogeneity. Egger's test and inverted funnel plots were used to investigate publication bias. Subgroup analysis was also performed. The results demonstrated that almost all the genetic models (except the model of CT vs. TT) indicated a significant association between rs11614913 polymorphism and CRC risk. The subgroup analysis in an Asian population also demonstrated similar results. However, there was no significant association of miR-196a2 rs11614913 polymorphism with the clinical characteristics of CRC patients. Our results confirmed the association of the polymorphism rs11614913 with the risk of CRC, but not with tumor stage and grade.

Pre-miR-27a rs895819A/G polymorphisms in cancer: a meta-analysis

BACKGROUND

MicroRNAs (miRNAs) negatively regulate the 3' untranslated region (3'-UTR) of coding genes by suppressing translation or degrading mRNAs, and they act as oncogenes or tumor suppressors. Recently, several studies investigated the association between pre-miR-27a rs895819 polymorphism and the risks of various cancers, but the results were inconsistent.

METHODOLOGY/PRINCIPAL FINDINGS

We conducted a meta-analysis of 13 studies that included 6501 cancer cases and 7571 controls to address this association. Overall, this meta-analysis showed that the pre-miR-27a rs895819 A/G polymorphism was not statistically associated with cancers risk in all genetic models. In the stratified analysis by cancer types, when compared with the ancestral A allele, individuals with the variant G allele was consistently associated with reduced risks of breast cancer (OR = 0.92, 95% CI = 0.85-0.99), renal cell cancer (OR = 0.81, 95% CI = 0.67-0.97) and nasopharyngeal cancer (OR = 0.84, 95% CI = 0.72-0.97). Inversely, individuals with the heterozygote AG was associated with an increased risk of digestive tract cancers compared with AA genotype (AG vs. AA: OR = 1.16, 95% CI = 1.01-1.32). In the stratified analysis by ethnicity, the pre-miR-27a rs895819 polymorphism showed statistically significant association with decreased risks of cancers in Caucasians (G vs. A allele: OR = 0.90, 95% CI = 0.83-0.97; AG vs. AA: OR = 0.84, 95% CI = 0.75-0.94; AG/GG vs. AA: OR = 0.85, 95% CI = 0.76-0.94) but not in Asians.

CONCLUSION/SIGNIFICANCE

This meta-analysis suggests that the pre-miR-27a rs895819 polymorphism may contribute to the susceptibilities of some specific-type of cancers, including breast cancer, renal cell cancer, nasopharyngeal cancer and digestive tract cancers, as well as the susceptibilities of cancers in Caucasians to some extent.