Associations of miRNA polymorphisms and female physiological characteristics with breast cancer risk in Chinese population

Lack of association between hsa-miR-149 rs2292832 polymorphism and cancer risk: a meta-analysis of 12 studies

BACKGROUND

MicroRNAs (miRNAs) participate in various cellular processes such as cell growth, differentiation, cell death and play an important role in a variety of diseases, especially in cancer. Recently, a number of studies have investigated the association between single nucleotide polymorphisms (SNPs) on the hsa-miR-149 rs2292832 and susceptibility to cancer; however, the results remain inconclusive.

METHODOLOGY/PRINCIPAL FINDINGS

We carried out a meta-analysis of 12 studies including 5937 cases and 6081 controls from PubMed to assess the association between the hsa-miR-149 rs2292832 and cancer risk by pooled odds ratios (ORs) and 95% confidence intervals (CIs). However, our results showed that genotype distribution of the hsa-miR-149 rs2292832 was not associated with cancer risk in all genetic models. Subgroup analysis by cancer type, ethnicity or study design showed no significant association either.

CONCLUSION

Results of this meta-analysis suggest that the hsa-miR-149 rs2292832 polymorphism is not associated with cancer risk in spite of the potentially protective role of C allele in hepatocellular carcinoma and male gastric cancer.

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.

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.

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.

Different effects of three polymorphisms in MicroRNAs on cancer risk in Asian population: evidence from published literatures

MicroRNAs (miRNAs) are a class of small non-protein-coding RNAs, which have emerged as integrated and important post-transcriptional regulators of gene expression. It has been demonstrated that single nucleotide polymorphisms (SNPs) exist in protein-coding genes. Accumulated studies have evaluated the association of miRNA SNPs with cancer risk, especially in Asian population, which included a series of related studies. However, the results remain controversial for the different genetic backgrounds, living habits and environment exposed. To evaluate the relationship between SNPs in miRNAs and cancer risk, 21 studies focused on Asian population were enrolled for the pooled analysis for three polymorphisms rs2910164, rs11614913, rs3746444 in three miRNAs miR-146aG>C, miR-196a2C>T, miR-499A>G using odds ratios (ORs) with 95% confidence intervals (CIs). For rs2910164 polymorphism, C allele was observed association with decreased overall cancer risk. In addition, subgroup analysis revealed of rs2910164 C allele decreased hepatocellular carcinoma (HCC), cervical cancer and prostate cancer risk among Chinese population. For rs11614913 polymorphism, TT genotype was observed to be associated with decreased cancer risk, especially for cancer type of colorectal cancer (CRC), lung cancer and country of Korea, North India. Whereas, rs3746444 G allele was an increased cancer risk factor in Chinese population, especially for breast cancer. In conclusion, this meta-analysis indicated that rs2910164 C allele was associated with decreased cancer risk in Chinese population. However, the association varied from different cancer types. Furthermore, TT genotype of rs11614913 was associated with decreased cancer risk. While different cancer types and countries contributed to different effects. Whereas, rs3746444 G allele was a risk factor in Chinese population, and the association varied from different cancer types.

The prognostic value of microRNAs varies with patient race/ethnicity and stage of colorectal cancer

PURPOSE

MicroRNAs (miRNA) have potential prognostic value for colorectal cancers; however, their value based on patient race/ethnicity and pathologic stage has not been determined. The goal was to ascertain the prognostic value of 5 miRNAs with increased expression in colorectal cancers of African American (black) and non-Hispanic Caucasian (white) patients.

EXPERIMENTAL DESIGN

TaqMan quantitative real-time PCR was used to quantify expression of miR-20a, miR-21, miR-106a, miR-181b, and miR-203 in paired normal and tumor colorectal cancer archival tissues collected from 106 black and 239 white patients. The results were correlated with overall survival based on patient race/ethnicity and pathologic stage. Because decisions about adjuvant therapy are important for stage III colorectal cancers, and because miR-181b seemed to have prognostic value only for stage III black patients, we assessed its prognostic value in a separate cohort of 36 stage III colorectal cancers of blacks.

RESULTS

All 5 miRNAs had higher expression in colorectal cancers (>1.0-fold) than in corresponding normal tissues. High expression of miR-203 was associated with poor survival of whites with stage IV colorectal cancers (HR = 3.00; 95% CI, 1.29-7.53), but in blacks it was an indicator of poor survival of patients with stages I and II colorectal cancers (HR = 5.63; 95% CI, 1.03-30.64). Increased miR-21 expression correlated with poor prognosis for white stage IV patients (HR = 2.50; 95% CI, 1.07-5.83). In both test and validation cohorts, high miR-181b expression correlated with poor survival of only black patients with stage III colorectal cancers (HR = 1.94; 95% CI, 1.03-3.67).

CONCLUSION

These preliminary findings suggest that the prognostic value of miRNAs in colorectal cancers varies with patient race/ethnicity and stage of disease.

Meta-Analysis of the Association between Mir-196a-2 Polymorphism and Cancer Susceptibility

Objective

MicroRNA plays a vital role in gene expression, and microRNA dysregulation is involved in carcinogenesis. The miR-196a-2 polymorphism rs11614913 is reportedly associated with cancer susceptibility. This meta-analysis was performed to assess the overall association of miR-196a-2 with cancer risk.

Methods

A total of 27 independent case-control studies involving 10,435 cases and 12,075 controls were analyzed for the rs11614913 polymorphism.

Results

A significant association was found between rs11614913 polymorphism and cancer risk in four genetic models (CT vs. TT, OR=1.15, 95%CI=1.05–1.27; CC vs. TT, OR=1.23, 95%CI=1.08–1.39; Dominant model, OR=1.17, 95%CI=1.06–1.30; Additive model, OR=1.08, 95%CI=1.01–1.14). In the subgroup analysis of different tumor types, the C allele was associated with increased risk of lung, breast, and colorectal cancer, but not with liver, gastric, or esophageal cancer. In the subgroup analysis by ethnicity, a significantly increased risk of cancer was found among Asians in all genetic models, but no associations were found in the Caucasian subgroup.

Conclusions

The meta-analysis demonstrated that the miR-196a-2 polymorphism is associated with cancer susceptibility, especially lung cancer, colorectal cancer, and breast cancer among Asian populations.

Association study between miR-149 gene polymorphism and nasopharyngeal carcinoma

Association studies between single-nucleotide polymorphism (SNP) rs2292832 on miR-149 gene and cancer risk have been previously analyzed in several types of cancer. The aim of this study was to evaluate the association between miR-149 polymorphism and risk of nasopharyngeal carcinoma (NPC). miR-149 gene polymorphism was genotyped using polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) in 158 patients with NPC and 242 healthy individuals. Associations with cancer risk and clinicopathological characteristics were analyzed by χ² test. No significant difference was observed for miR-149 gene polymorphism in NPC patients and healthy controls in either genotype (P=0.427 for CC vs. CT vs. TT, P=0.247 for CT vs. TT and P=0.323 for CC vs. TT, respectively) or allelic analysis (P=0.216). No significant difference was noted between the genotypes and the clinicopathological parameters examined with the exception of clinical stage. A significantly higher CC distribution in clinical stage I-II compared with III-IV was observed under the dominant model (CC vs. CT vs. TT, P=0.026) and the co-dominant model (CC vs. TT, P=0.030). The results of this study suggested that the CC genotype of miR-149 contributes to the progression and development, rather than the initiation of NPC.

The Hsa-miR-27a rs895819 (A>G) polymorphism and cancer susceptibility

Published data on the association between the rs895819 (A>G) polymorphism in the terminal loop of pre-miR-27a and cancer risk is inconclusive. Therefore, we conducted a meta-analysis to estimate the association between this polymorphism and cancer. The PubMed, Web of science, and Embase databases were searched for articles on the hsa-miR-27a rs895819 polymorphism and cancer risk published up to November 24, 2012. The genotype data obtained in the searches were pooled in our meta-analysis, and pooled odds ratio (OR) with 95% confidence interval (CI) was used to assess the association. Seven studies with a total of 3849 cases and 4781 controls were eligible for analysis. Overall, we found no significant associations between the hsa-miR-27a rs895819 (A>G) polymorphism and cancer susceptibility (homozygote model: OR=0.88, 95% CI: 0.68-1.14; heterozygote model: OR=0.96, 95% CI: 0.79-1.17; dominant model: OR=0.94, 95% CI: 0.79-1.12; recessive model: OR=0.88, 95% CI: 0.69-1.12). In the subgroup analysis by ethnicity, we found that the rs895819 AG genotype was associated with a decreased risk of cancer in white individuals (dominant model: OR=0.85, 95% CI: 0.76-0.94; heterozygote model: OR=0.84, 95% CI: 0.75-0.94). This meta-analysis indicated that the hsa-miR-27a rs895819 polymorphism did not correlate with overall cancer risk in the general population. However, the rs895819 AG genotype may protect against the development of cancer in white individuals. Larger, better studies of homogeneous cancer patients are needed to further assess the correlation between this polymorphism and cancer risk.

Differential expression of miR-145 in children with Kawasaki disease

BACKGROUND

Kawasaki disease is an acute, self-limited vasculitis of childhood that can result in structural damage to the coronary arteries. Previous studies have implicated the TGF-β pathway in disease pathogenesis and generation of myofibroblasts in the arterial wall. microRNAs are small non-coding RNAs that modulate gene expression at the post-transcriptional level and can be transported between cells in extracellular vesicles. To understand the role that microRNAs play in modifying gene expression in Kawasaki disease, we studied microRNAs from whole blood during the acute and convalescent stages of the illness.

METHODOLOGY/PRINCIPAL FINDINGS

RNA isolated from the matched whole blood of 12 patients with acute and convalescent Kawasaki disease were analyzed by sequencing of small RNA. This analysis revealed six microRNAs (miRs-143, -199b-5p, -618, -223, -145 and -145* (complementary strand)) whose levels were significantly elevated during the acute phase of Kawasaki disease. The result was validated using targeted qRT-PCR using an independent cohort (n = 16). miR-145, which plays a critical role in the differentiation of neutrophils and vascular smooth muscle cells, was expressed at high levels in blood samples from acute Kawasaki disease but not adenovirus-infected control patients (p = 0.005). miR-145 was also detected in small extracellular vesicles isolated from acute Kawasaki disease plasma samples. Pathway analysis of the predicted targets of the 6 differentially expressed microRNAs identified the TGF-β pathway as the top pathway regulated by microRNAs in Kawasaki disease.

CONCLUSION

Sequencing of small RNA species allowed discovery of microRNAs that may participate in Kawasaki disease pathogenesis. miR-145 may participate, along with other differentially expressed microRNAs, in regulating expression of genes in the TGF-β pathway during the acute illness. If the predicted target genes are confirmed, our findings suggest a model of Kawasaki disease pathogenesis whereby miR-145 modulates TGF-β signaling in the arterial wall.

Pre-mir-27a rs895819 polymorphism and cancer risk: a meta-analysis

Aberrant expression of miRNAs plays critical roles in cancer development. Single nucleotide polymorphism (SNP) in miRNA precursors may affect miRNA expression levels. An important SNP in the pre-mir-27a with a A to G change (rs895819) was identified. Several original studies have explored the role of this SNP in cancer risk, but the results of these studies remain conflicting rather than conclusive. Therefore, we performed a meta-analysis of the published studies to derive a more precise estimation of the association between pre-mir-27a rs895819 polymorphism and cancer risk. In this meta-analysis, a total of 6 case-control studies (including 3,255 cases and 4,181 controls) were analyzed. The results of the overall meta-analysis did not suggest any associations between pre-mir-27a rs895819 polymorphism and cancer susceptibility. However, an decreased risk was observed in the subgroup of breast cancer patients (G vs A: OR = 0.90, 95 % CI = 0.83 ~ 0.97; P heterogeneity = 0.75) or in the subgroup of Caucasian race (G vs A: OR = 0.90, 95 % CI = 0.83 ~ 0.97, P heterogeneity = 0.78, I (2) = 0; AG vs AA: OR = 0.84, 95 % CI = 0.75 ~ 0.94, P heterogeneity = 0.35, I (2) = 3.7 %; GG+AG vs AA: OR = 0.85, 95 % CI = 0.76 ~ 0.94, P heterogeneity = 0.48, I (2) = 0). The findings suggest that pre-mir-27a rs895819 polymorphism may have some relation to breast cancer susceptibility or cancer development in Caucasian.

Genetic variations in miR-27a gene decrease mature miR-27a level and reduce gastric cancer susceptibility

MicroRNAs (miRNAs) are noncoding RNAs that function as post-transcriptional regulators of tumor oncogenes and suppressors. Single-nucleotide polymorphisms (SNPs) in miRNA genes are a novel class of genetic variations in the human genome that are currently being identified and investigated in human cancers. In this study, we aimed to investigate whether SNPs in the miR-27a gene affect miR-27a expression and alter susceptibility to gastric cancer. Therefore, we conducted a case-control population study and the allele and genotype frequencies for polymorphism rs11671784 in miR-27a gene were examined in the study population. As a result, we found that the G/A polymorphism in the miR-27a gene exhibited a significant effect on gastric cancer risk. Compared with GG homozygotes, subjects who were GA heterozygotes or AA homozygotes exhibited a decreased risk of gastric cancer. The G/A polymorphism impaired the processing of pre-miR-27a to mature miR-27a, resulting in significantly reduced expression of mature miR-27a and an increased level of its target HOXA10. Furthermore, we confirmed these findings in in vitro studies by overexpressing pre-miR-27a carrying G or A allele. It provided further evidence demonstrating that allelic difference of rs11671784 is linked to gastric tumorigenesis. In summary, our results indicate that the G/A polymorphism in miR-27a gene (rs11671784) decreases miR-27a expression, reduces gastric cancer risk and plays a role in gastric tumorigenesis. This is the first study to address the role and function of miR-27a polymorphism rs11671784 in gastric cancer. These results could be useful to assess individual susceptibility of gastric cancer and will improve our understanding of the potential contribution of miRNA SNPs to cancer pathogenesis.

The association between genetic polymorphism and the processing efficiency of miR-149 affects the prognosis of patients with head and neck squamous cell carcinoma

MicroRNAs (miRNAs) play important roles in modulating the neoplastic process of cancers including head and neck squamous cell carcinoma (HNSCC). A genetic polymorphism (rs2292832, C>T) has been recently identified in the precursor of miR-149; nevertheless its clinicopathological implications remain obscure. In this study, we showed that miR-149 is down-regulated in HNSCC compared to normal mucosa and this is associated with a poorer patient survival. In addition, HNSCC patients with the T/T genotype have more advanced tumors and a worse prognosis. Multivariate analysis indicated that patients carried the T/T genotype have a 2.81-fold (95% CI: 1.58–4.97) increased risk of nodal metastasis and 1.66-fold (95% CI: 1.05–2.60) increased risk of mortality compared to other groups. T/T genotype also predicted the worse prognosis of buccal mucosa carcinoma subset of HNSCC. In vitro analysis indicated that exogenous miR-149 expression reduces the migration of HNSCC cells. Moreover, HNSCC cell subclones carrying the pri-mir-149 sequence containing the T variant show a low processing efficacy when converting the pre-mir-149 to mature miR-149. These findings suggest that miR-149 suppresses tumor cell mobility, and that the pre-mir-149 polymorphism may affect the processing of miR-149, resulting in a change in the abundance of the mature form miRNA, which, in turn, modulates tumor progression and patient survival.

Comprehensive review of genetic association studies and meta-analyses on miRNA polymorphisms and cancer risk

BACKGROUND

MicroRNAs (miRNAs) are small RNA molecules that regulate the expression of corresponding messenger RNAs (mRNAs). Variations in the level of expression of distinct miRNAs have been observed in the genesis, progression and prognosis of multiple human malignancies. The present study was aimed to investigate the association between four highly studied miRNA polymorphisms (mir-146a rs2910164, mir-196a2 rs11614913, mir-149 rs2292832 and mir-499 rs3746444) and cancer risk by using a two-sided meta-analytic approach.

METHODS

An updated meta-analysis based on 53 independent case-control studies consisting of 27573 cancer cases and 34791 controls was performed. Odds ratio (OR) and 95% confidence interval (95% CI) were used to investigate the strength of the association.

RESULTS

Overall, the pooled analysis showed that mir-196a2 rs11614913 was associated with a decreased cancer risk (OR = 0.846, P = 0.004, TT vs. CC) while other miRNA SNPs showed no association with overall cancer risk. Subgroup analyses based on type of cancer and ethnicity were also performed, and results indicated that there was a strong association between miR-146a rs2910164 and overall cancer risk in Caucasian population under recessive model (OR = 1.274, 95%CI = 1.096-1.481, P = 0.002). Stratified analysis by cancer type also associated mir-196a2 rs11614913 with lung and colorectal cancer at allelic and genotypic level.

CONCLUSIONS

The present meta-analysis suggests an important role of mir-196a2 rs11614913 polymorphism with overall cancer risk especially in Asian population. Further studies with large sample size are needed to evaluate and confirm this association.

Microrna-149 Inhibits Proliferation and Invasion of Glioma Cells via Blockade of Akt1 Signaling

MicroRNAs (miRNAs) play important roles in the regulation of gene expressions. Aberrant expression of miRNAs is implicated in a variety of biological and pathological processes, including the tumorigenesis of glioma (GM). Though the molecular mechanisms of protein kinase B (AKT) survival signal have been comprehensively explored, the role of miR-149 in glioblastoma (GBM) and its regulation on AKT signaling have not yet been ascertained. The present study aimed to elucidate the role and molecular mechanisms of miR-149 in U251 GM cells. Using a gain-of-function approach, we investigated the effects of lentivirus-mediated overexpression of miR-149 on the expression of phosphated-AKT1 (p-AKT1), proliferating cell nuclear antigen (PCNA), matrix metallopeptidase-2 (MMP-2) and CyclinD1 in U251 cells and nude mice subcutaneous xenograft tumors by Real-time PCR, Western blot and immunohistochemical assays. Proliferative activities indicated by MTT assay, invasive potential by Transwell and cycle distribution by flow cytometry were carried out for functional analysis of U251 cells after infection with miR-149 mimic. As a consequence, miR-149 inhibited the expression of p-AKT1, PCNA, CyclinD1 and MMP-2, reduced the proliferative activities and invasive potential, and induced cycle arrest in G0/G1 phase in U251 cells. In conclusion, our findings show that miR-149 as tumor suppressor may be involved in the proliferation and invasion of GM cells via blockade of the AKT1 signaling, and be considered as a candidate target for the treatment of cancer.

Lack of association between miR-149 C>T polymorphism and cancer susceptibility: a meta-analysis based on 4,677 cases and 4,830 controls

To derive a more precise estimation of the relationship between miR-149 C>T polymorphism and cancer risk, a meta-analysis was performed. A total of 8 studies including 4,677 cases and 4,830 controls were involved in this meta-analysis. Overall, no significantly elevated cancer risk was associated with miR-149 T allele when all studies were pooled into the meta-analysis (CT vs. CC: OR = 0.977, 95 % CI = 0.882-1.082; TT vs. CC: OR = 0.985, 95 % CI = 0.857-1.132; dominant model: OR = 0.984, 95 % CI = 0.893-1.084; recessive model: OR = 1.026, 95 % CI = 0.931-1.132). In the subgroup analysis by ethnicity or study design, no significantly increased risks were found under all models. When stratified by cancer type, there were no significant cancer risk changes for lung cancer, breast cancer or colorectal cancer when miR-149 T allele was included. In conclusion, this meta-analysis suggests that the miR-149 C>T polymorphism may not contribute to cancer susceptibility.