Genotype GG of rs895819 Functional Polymorphism Within miR-27a Might Increase Genetic Susceptibility to Colorectal Cancer in Han Chinese Population

Genetic Variation in miR-27a Is Associated with Fluoropyrimidine-Associated Toxicity in Patients with Dihydropyrimidine Dehydrogenase Variants after Genotype-Guided Dose Reduction

Dihydropyrimidine dehydrogenase (DPYD) is the rate-limiting enzyme involved in the metabolism of fluoropyrimidine-based chemotherapy. However, single-nucleotide variants (SNVs) in DPYD only partially explain fluoropyrimidine-induced toxicity. The expression of DPYD has previously been shown to be regulated by microRNA-27a (miR-27a) and a common miR-27a SNV (rs895819) has been associated with an increased risk of toxicity in patients harboring a DPYD variant who received standard fluoropyrimidine dosing. We investigated if the miR-27a rs895819 SNV was associated with toxicity in DPYD wildtype patients and carriers of DPYD variants who received a reduced dose. The regulation of DPYD using miR-27a was investigated in HepG2 cells utilizing a miR-27a mimic. miR-27a overexpression decreased DPYD mRNA expression compared to control cells (p < 0.0001). In a cohort of patients that received pre-emptive DPYD genotyping, 45 patients had a DPYD variant and 180 were wildtype. Patients heterozygous for rs895819 had an increased risk of toxicity, which was seen in both patients who were wildtype for DPYD variants (OR (95%CI) = 1.99 (1.00-3.99)) and DPYD variant carriers (OR (95%CI) = 8.10 (1.16-86.21)). Therefore, miR-27a rs895819 may be a clinically relevant predictor of fluoropyrimidine-associated toxicities. Furthermore, toxicity was more profound in DPYD variant carriers, even after DPYD genotype-guided dose reduction. This suggests that patients may benefit from miR-27a genotyping to guide fluoropyrimidine dosing.

A Review of IsomiRs in Colorectal Cancer

As advancements in sequencing technology rapidly continue to develop, a new classification of microRNAs has occurred with the discovery of isomiRs, which are relatively common microRNAs with sequence variations compared to their established template microRNAs. This review article seeks to compile all known information about isomiRs in colorectal cancer (CRC), which has not, to our knowledge, been gathered previously to any great extent. A brief overview is given of the history of microRNAs, their implications in colon cancer, the canonical pathway of biogenesis and isomiR classification. This is followed by a comprehensive review of the literature that is available on microRNA isoforms in CRC. The information on isomiRs presented herein shows that isomiRs hold great promise for translation into new diagnostics and therapeutics in clinical medicine.

A functional SNP rs895819 on pre-miR-27a is associated with bipolar disorder by targeting NCAM1

The aberrant expression or genomic mutations of microRNA are associated with several human diseases. This study analyzes the relationship between genetic variations of miRNA and schizophrenia or bipolar disorder. We performed case-control studies for ten SNPs in a total sample of 1584 subjects. All these ten SNPs were on or near mature microRNAs. We identified the association between bipolar disorder and the T/C polymorphism at rs895819. To illustrate the function of miR-27a, we constructed several miR-27a knockout (KO) cell lines, determined candidates of miR-27a, and then verified NCAM1 as a target gene of miR-27a. Further studies revealed that the T/C polymorphism on miR-27a led to the differential expression of mature and precursor miR-27a without affecting the expression of primary miR-27a. Furthermore, the C mutation on pre-miR-27a suppresses cell migration and dopamine expression levels. Our study highlights the importance of miR-27a and its polymorphism at rs895819 in bipolar disorder.

A T/C variant in miR-27a is associated with bipolar disorder, potentially by reducing the ability of this microRNA to target important neurodevelopmental genes like NCAM1.

The association of PRNCR1 rs1456315 polymorphism with the risk of colorectal cancer

A recent meta-analysis found a link between the PRNCR1 rs1456315 polymorphism and cancer risk. In the current study, we further investigated the association of this polymorphism with the risk and clinical stage of colorectal cancer (CRC). A total of 416 CRC patients and 416 healthy individuals were genotyped by Sanger sequencing. Logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). Furthermore, a pooled analysis with 872 CRC cases and 1141 controls was performed by Stata 12.0 software. In both the case-control study and the pooled analysis, there was no significant link between the rs1456315 polymorphism and CRC risk. However, there was a significant link between the rs1456315 polymorphism and the clinical stage of CRC. CRC patients carrying the rs1456315 G allele were more likely to have a high-stage tumor. Further bioinformatics analysis showed that the rs1456315 polymorphism could influence the binding of miRNA to PRNCR1. In conclusion, the findings suggest that the rs1456315 polymorphism is linked to CRC clinical stage and might be used as a biomarker to predict CRC progression.

Single Nucleotide Polymorphisms in microRNA Genes and Colorectal Cancer Risk and Prognosis

There is growing interest in single nucleotide polymorphisms (SNPs) in the genes of microRNAs (miRNAs), which could be associated with susceptibility to colorectal cancer (CRC) and therefore for prognosis of the disease and/or treatment response. Moreover, these miRNAs-SNPs could serve as new, low-invasive biomarkers for early detection of CRC. In the present article, we performed a thorough review of different SNPs, which were investigated for a correlation with the CRC risk, prognosis, and treatment response. We also analyzed the results from different meta-analyses and the possible reasons for reported contradictory findings, especially when different research groups investigated the same SNP in a gene for a particular miRNA. This illustrates the need for more case-control studies involving participants with different ethnic backgrounds. According to our review, three miRNAs-SNPs-miR-146a rs2910164, miR-27a rs895819 and miR-608 rs4919510-appear as promising prognostic, diagnostic and predictive biomarkers for CRC, respectively.

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.

The association of miR-27a rs895819 polymorphism with colorectal cancer risk in Chinese population

Background

Besides environment and living habits, such as a sedentary lifestyle, smoking and drinking, genetic variation also plays an important role in the development of colorectal cancer (CRC). This study was aimed to investigate the role of miR‑27a rs895819 polymorphism on CRC risk in Chinese population.

Methods

In a case‐control study including 208 CRC and 312 age‐ and gender‐matched healthy control subjects, the rs895819 polymorphism was genotyped using the TaqMan allelic discrimination assay. Furthermore, a pooled analysis based on eligible studies was performed by using the STATA software.

Results

Logistic regression analysis showed that the rs895819 polymorphism was not associated with CRC risk. However, a pooled analysis based on five studies from Chinese population showed a statistically significant association between the rs895819 polymorphism and CRC risk (GG vs AA: OR = 1.56, 95% CI = 1.27‐1.92, Pz < .01; (AG + GG) vs AA: OR = 1.14, 95% CI = 1.01‐1.30, Pz = .04; GG vs (AG + AA): OR = 1.54, 95% CI = 1.27‐1.88, Pz < .01; G vs A: OR = 1.20, 95% CI = 1.09‐1.33, Pz < .01).

Conclusion

Our study suggests that miR‑27a rs895819 polymorphism plays an important role in CRC risk in Chinese population and may serve as a valuable biomarker for predicting an individual's susceptibility to CRC.

Association of microRNA-27a rs895819 polymorphism with the risk of cancer: An updated meta-analysis

BACKGROUND

MiR-27a rs895819 polymorphism is considered as a tumor- related susceptibility gene. Previous meta-analyses evaluated the association the association between miR-27a rs895819 and cancer risk, but the results were inconsistent. The present meta-analysis was carried out to better estimate the correlation of rs895819 and cancer susceptibility.

METHODS

We searched several databases to identify relevant studies, including PubMed, EMBASE and the Cochrane Controlled Trials Register. The odds ratios (ORs) with 95% confidence intervals (CIs) were used to estimate the association between miR-27a rs895819 and cancer risk.

RESULTS

The overall analysis showed the miR-27a rs895819 was not associated with cancer susceptibility in all models (dominant model: OR = 1.02, 95% CI:0.94-1.10, p = 0.632; recessive model: OR = 1.05, 95% CI: 0.92-1.76, p = 0.474; homozygote model: OR = 1.06, 95% CI: 0.91-1.23, p = 0.439; heterozygote model: OR = 1.00, 95% CI: 0.93-1.08, p = 0.934; and allele model: OR = 1.02, 95% CI: 0.96-1.09, p = 0.486). Interestingly, rs895819 A > G was significantly associated with colorectal cancer risk in recessive model (OR = 1.54, 95% CI: 1.29-1.83, p < 0.001), homozygote model (OR = 1.59, 95% CI: 1.31-1.92, p < 0.001), and allele model (OR = 1.22, 95% CI: 1.10-1.34, p < 0.001). In addition, rs895819 polymorphism was correlated with increased risk of breast cancer in the recessive model (OR = 0.81, 95% CI: 0.66-1.00, p = 0.046) and allele model (OR = 0.89, 95% CI: 0.80-0.98, p = 0.021).

CONCLUSIONS

Our results suggested that rs895819 polymorphism was correlated with increased risk of colorectal cancer and breast cancer, but not all types of cancer.

Pre-miR-27a rs895819 polymorphism and risk of diffuse large B-cell lymphoma

Background

Recently, several studies have investigated the relationship between Pre‐miR‐27a rs895819 polymorphism and risk of various cancers. However, the relationship between rs895819 and diffuse large B‐cell lymphoma (DLBCL) has not been well known.

Methods

In this study, we conducted a case‐control study to explore the role of Pre‐miR‐27a rs895819 in risk of DLBCL. The PCR‐TaqMan and luciferase assays and in vitro experiments were used to evaluate polymorphism function.

Results

As a result, we found subjects carrying with rs895819 AG/GG genotype had a significantly decreased risk when compared with those carrying the AA genotype. Further qPCR assay showed that the DLBCL patients carrying AG/GG genotypes showed a lower level of mature miR‐27a when compared with patients carrying AA genotype. Moreover, miR‐27a levels were upregulated in DLBCL tissues compared with normal lymphoid tissues. Further in vitro experiments showed that miR‐27a might function as an oncogene through target TGFBR1. In addition, TGFBR1 overexpression rescues effects of miR‐27a inhibitor on DLBCL cells phenotypes.

Conclusions

In conclusion, these findings indicate that rs895819 A > G might reduce the expression of mature miR‐27a, and leading a higher level of TGFBR1, ultimately inhibiting the development of DLBCL.

Polymorphisms in non-coding RNAs and risk of colorectal cancer: A systematic review and meta-analysis

Colorectal cancer (CRC) has been regarded as a common cancer due to its prevailing incidence in both males and females. Recently, non-coding RNAs used as biomarkers for screening, diagnosis and prognosis of different cancers have been under the focus of attention. As a result of this, the aim of this study was to systematically review articles that investigated the SNPs in genes related to microRNAs and long non-coding RNAs to assess the genetic susceptibility of colorectal cancer risk. The outcome is presented as the results of a meta-analysis. We systematically searched PubMed, Web of Science, and Scopus to identify relevant studies published up to 20/5/2017. These included eligible studies consisting of 23,581 patients and 22,697 controls. The conferred risk was estimated and presented using odds ratios (ORs) and 95% confidence intervals (CI). The Hardy-Weinberg equilibrium (HWE) was assessed by the goodness-of-fit chi-square test in all studies. The power of each study was also calculated based on the available results. Out of 27 different microRNAs which had published results, although most of the studies were under powered, miR-146a and miR-196a were amongst the most studied microRNAs. For five miRNAs (miR-196a, miR-146a, miR-27a, miR-499 and miR-149) which we performed a meta-analysis, miR-27a and miR-149 gene polymorphisms were associated with susceptibility to CRC. Other miRNAs did not show any effect on the CRC risk. Overall, significant association between miR-149 rs2292832 and susceptibility to cancer was identified in a recessive genetic model, TT/ (TC + CC) (OR = 1.19, 95% CI = 1.02-1.39, P = 0.02). On the other hand, rs895819 (miR-27a) GG carriers were more susceptible to CRC (OR = 1.47, 95% CI = 1.21-1.78, P = <0.05) in a recessive genetic model. Analysis of the data based on race revealed that rs2910164 (miR-146a) polymorphism may decrease the risk of CRC among Europeans, in a co dominant model [OR = 0.81, 95% CI 0.66-0.99, p = 0.04], but not among Asians. In conclusion, certain miRNAs (miR-27a and miR-149) may affect the CRC risk and can be regarded as genetic markers amongst different populations. LncRNAs still have to be studied more to reach a conclusion for their association with CRC risk.

Association of two microRNA polymorphisms miR-27 rs895819 and miR-423 rs6505162 with the risk of cancer

Many studies have been conducted to investigate the association between miR-27 rs895819 A > G and miR-423 rs6505162 C > A and cancer risk; however, the results are not consistent. In order to acquire a more precise assessment of the correlation, we performed this meta-analysis. We searched PubMed, EMBASE and Web of Science databases to identify eligible studies. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were applied to evaluate the correlation of these two microRNA polymorphisms with cancer risk. Forty-five eligible studies from thirty-five articles were included in our analysis. The results showed that rs895819 was associated with a decreased cancer risk in Caucasians (AG vs. AA: OR = 0.87, 95% CI = 0.79-0.96; GG+AG vs. AA: OR = 0.89, 95% CI = 0.81-0.98). When grouped by ethnicity, an increased risk was observed in colorectal cancer (G vs. A: OR = 1.19, 95% CI = 1.08-1.32; GG vs. AA: OR = 1.58, 95% CI = 1.28-1.96; GG vs. AG+AA: OR = 1.58, 95% CI = 1.29-1.93), while a decreased risk was found in breast cancer (G vs. A: OR = 0.93, 95% CI = 0.87-0.99; GG+AG vs. AA: OR = 0.91, 95% CI = 0.83-0.99). For rs6505162, a significantly decreased cancer risk was observed in lung cancer under all five genetic models. To summarize, our results indicated that rs895819 was a protective factor for cancer in Caucasians and could increase colorectal cancer risk but decrease breast cancer risk. Moreover, rs6505162 was a protective factor for lung cancer.

Methylated claudin-11 associated with metastasis and poor survival of colorectal cancer

As one of crucial epigenetic modification, DNA methylation plays an important role during the carcinogenesis of colorectal cancer (CRC). In the current study, we used a human genome methylation array to detect the aberrant methylation genes in CRC. We further identified the hypermethylation of claudin-11 (CLDN11) and proved inverse correlation between CLDN11 methylation and its expression in CRC. In vitro experiments showed debased migration ability of colonic cancer cells in accompany with the converted methylation of CLDN11 after colonic cancer cells treated with demethylation agent, 5-aza-2'-deoxycytidine. Besides, our results also represented that hypermethylation of CLDN11 was associated with increased metastatic potential of CRC and with low progression free survival (PFS) of CRC. In conclusion, our findings supported that the hypermethylated CLDN11 is associated with metastasis of CRC and prognosis of poor survival of CRC.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

MicroRNAs and Drinking: Association between the Pre-miR-27a rs895819 Polymorphism and Alcohol Consumption in a Mediterranean Population

Recently, microRNAs (miRNA) have been proposed as regulators in the different processes involved in alcohol intake, and differences have been found in the miRNA expression profile in alcoholics. However, no study has focused on analyzing polymorphisms in genes encoding miRNAs and daily alcohol consumption at the population level. Our aim was to investigate the association between a functional polymorphism in the pre-miR-27a (rs895819 A>G) gene and alcohol consumption in an elderly population. We undertook a cross-sectional study of PREvención con DIeta MEDiterránea (PREDIMED)-Valencia participants (n = 1007, including men and women aged 67 ± 7 years) and measured their alcohol consumption (total and alcoholic beverages) through a validated questionnaire. We found a strong association between the pre-miR-27a polymorphism and total alcohol intake, this being higher in GG subjects (5.2 ± 0.4 in AA, 5.9 ± 0.5 in AG and 9.1 ± 1.8 g/day in GG; padjusted = 0.019). We also found a statistically-significant association of the pre-miR-27a polymorphism with the risk of having a high alcohol intake (>2 drinks/day in men and >1 in women): 5.9% in AA versus 17.5% in GG; padjusted < 0.001. In the sensitivity analysis, this association was homogeneous for sex, obesity and Mediterranean diet adherence. In conclusion, we report for the first time a significant association between a miRNA polymorphism (rs895819) and daily alcohol consumption.

Association between microRNA-27a rs895819 polymorphism and risk of colorectal cancer: A meta-analysis

Colorectal cancer (CRC) is the most common malignancy in the human digestive system. Previous results regarding the association between microRNA-27a rs895819 polymorphisms and CRC risk are controversial. We therefore performed a meta-analysis of seven studies totaling 2230 cases and 2775 controls to systematically evaluate this association. Summary odds ratios (ORs) and 95% confidence intervals (CIs) were obtained using a fixed-effects model. A moderate evidence for the association between mir-27a polymorphism and CRC risk was found under multiple genetic models (dominant model: OR = 1.15, 95% CI: 1.02-1.29, p = 0.02; recessive model: OR = 1.49, 95% CI: 1.27-1.76, p <0.001; homozygote model: OR = 1.53, 95% CI: 1.28-1.83, p <0.001; allele model: OR = 1.21, 95% CI: 1.11-1.31, p <0.001). Subgroup analysis showed a significant association between mir-27a rs895819 polymorphism and CRC risk among Chinese populations. On the contrary, we found no evidence of association among Caucasian populations due to small samples (p > 0.05). In conclusion, this meta-analysis suggested that rs895819 polymorphism in mir-27a may be a potential genetic risk factor for CRC, particularly in Chinese populations.