Polymorphism in mature microRNA-608 sequence is associated with an increased risk of nasopharyngeal carcinoma

The Role of Single Nucleotide Polymorphisms in MicroRNA Genes in Head and Neck Squamous Cell Carcinomas: Susceptibility and Prognosis

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is one of the most prevalent cancers worldwide. The identification of molecular alterations adding to the individual risk of HNSCC development and progression is one of the most important challenges in studies on cancer genetics. MicroRNAs (miRNAs), which belong to the group of important post-transcriptional regulators of human gene expression, seem to be valuable options for consideration as key modifiers of individual cancer risk, and therefore may be helpful in predicting inter-individual differences in cancer risk, response to treatment and prognosis.

METHODS

There have not been many studies focused on the relationship between miRNA variants and HNSCC published in PubMed within the last 15 years. We found and analyzed 30 reviews, meta-analyses and research papers and revealed 14 SNPs which have been reported as significant in the context of HNSCC susceptibility and/or prognosis.

RESULTS

These 14 SNPs were located in 13 separate miRNAs. Among them, four were the most frequently studied (miRNA-146, -196, -149 and -499) and have been shown to have the greatest impact on the course of HNSCC. However, the presented results have been conflicting.

CONCLUSIONS

It must be concluded that, despite the years of studies, there are no conclusive reports demonstrating a significant role of SNPs in miRNAs in the context of the susceptibility to HNSCC or its prognosis.

Integration of Human and Viral miRNAs in Epstein-Barr Virus-Associated Tumors and Implications for Drug Repurposing

Epstein-Barr virus (EBV) is associated with several tumors, and has substantial relevance for public health. Therapeutics innovation for EBV-related disorders is much needed. In this context, miRNAs are noncoding RNA molecules that play vital roles in EBV infection. miRNA-Seq and RNA-Seq data for EBV-associated clinical samples and cell lines have been generated, but their detailed integrative analyses, and exploitation for drug repurposing against EBV are lacking. Hence, we identified and analyzed the differentially expressed miRNAs (DEmiRs) in EBV-infected cell lines (28) and infected (28) and uninfected human tissue (20) samples using an in-house pipeline. We found significantly enriched host miRNAs like hsa-mir-3651, hsa-mir-1248, and hsa-mir-29c-3p in EBV-infected samples from EBV-associated nasopharyngeal carcinoma and Hodgkin's lymphoma, among others. Furthermore, we also identified significantly enriched novel miRNAs such as hsa-mir-29c-3p, hsa-mir-3651, and hsa-mir-98-3p, which were not previously reported in EBV-related tumors. Differentially expressed mRNAs (DEMs) were identified in EBV-infected cell lines (21) and uninfected human tissue (14) samples. We predicted and selected 1572 DEMs (upregulated) that are targeted by 547 DEmiRs (downregulated). These were further classified into essential (870) and nonessential (702) genes. Moreover, a miRNA-mRNA network was developed for the hub miRNAs. Importantly, we used the DEMs during EBV latent infection types I, II, and III to identify the candidate drugs for repurposing: Glyburide, Levodopa, Nateglinide, and Stiripentol, among others. To the best of our knowledge, this is the first integrative analyses that identified DEmiRs and DEMs as potential therapeutic targets and predicted drugs as potential candidates for repurposing against EBV-related tumors.

Biological Functions and Molecular Mechanisms of MiR-608 in Cancer

In recent years, microRNAs (miRNAs) have attracted much attention because of their prominent role in cancer. An increasing number of studies have shown that miRNAs play an important role in a variety of tumors. miR-608 has been reported to be decreased in cancers, especially in solid tumors. miR-608 is regarded as a tumor suppressor, which has been verified through a large number of experiments both in vivo and in vitro. miR-608 participates in many biological processes, including cell proliferation, invasion, migration, and apoptosis, by inhibiting transmembrane proteins and many signaling pathways. Here, we summarize the expression profile and biological functions and mechanism of miR-608, suggesting that miR-608 is an ideal diagnostic and prognostic biomarker and a treatment target for cancer.

MiR-608 rs4919510 C > G polymorphism increased the risk of bladder cancer in an Iranian population

MicroRNAs (miRNAs) participate in diverse biological pathways and may act as oncogenes or tumor suppressors. The single nucleotide polymorphisms (SNPs) in miRNAs potentially can alter miRNA-binding sites on target genes as well as affecting miRNAs expression. The present study aimed to evaluate the impact of miR-608 rs4919510 C > G variant on bladder cancer risk. This case-control study conducted on 233 bladder cancer patients and 252 healthy subjects. Genotyping of miR-608 rs4919510 was done using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Our findings showed that CG as well as CG + GG genotypes significantly increased the risk of bladder cancer (OR = 1.94, 95% CI = 1.28–2.94, p = 0.002, and OR = 1.90, 95% CI = 1.26–2.86, p = 0.002, respectively) compared to CC genotype. The G allele significantly increased the risk of bladder cancer compared to C allele (OR = 1.69, 95% CI = 1.17–2.45, p = 0.005). Our findings proposed that miR-608 polymorphism might be associated with increased risk of bladder cancer in a sample of Iranian population. Further large-scale studies with different ethnicities are needed to verify our findings.

miR-608 rs4919510 Polymorphism May Affect Susceptibility to Colorectal Cancer by Upregulating MRPL43 Expression

There are many studies on the association between miR-608 rs4919510 polymorphism and susceptibility to colorectal cancer (CRC). However, the role of rs4919510 in CRC development and its underlying mechanism remain unclear. We first evaluated the gene that may be regulated by the variation of rs4919510 through a two-stage expression quantitative trait loci analysis and then compared the expression of that identified gene in CRC tissues and adjacent nontumor tissues. Next, methyl thiazolyl tetrazolium (MTT) assay, transwell assay, and flow cytometry analyses were performed to investigate the in vitro capacity of cell proliferation, migration, invasion, apoptosis, and cell cycle of CRC cells, respectively. Finally, through bioinformatics prediction, we contrasted the regulatory network and identified microRNAs (miRNAs) and long noncoding RNAs (lncRNAs) that could regulate the obtained gene. We found that the variant G allele of rs4919510 located in miR-608 was associated with a potentially increased expression of MRPL43 in colon tissues (p = 0.065). Moreover, the results of functional experiments suggested that knockdown of the MRPL43 gene could inhibit the growth of the CRC HCT-116 cell line and promote apoptosis. Additionally, the cell cycle of CRC HCT-116 cell line was significantly arrested at the G2 phase. Next, we obtained a competing endogenous RNA regulatory network of MRPL43 with 17 pairs of miRNAs-lncRNAs by bioinformatics prediction, out of which, survival analysis indicated that different expression levels of miR-193b-3p (p = 0.0269) and miR-194-3p (p = 0.0113) were associated with overall survival in CRC patients. The rs4919510 variant G allele in miR-608 may increase the proliferation, invasion, and migration ability and decrease the apoptosis of CRC HCT-116 cell line by upregulating the expression of MRPL43, ultimately may affect the risk of CRC. Moreover, miR-193b-3p and miR-194-3p that target MRPL43 may serve as potential predictive biomarkers of CRC survival.

Association of miR-4293 rs12220909 polymorphism with cancer risk: A meta-analysis of 8394 subjects

BACKGROUND

Several studies have investigated miR-4293 rs12220909 polymorphisms and cancer susceptibility and yielded different results. Because of this controversy, we designed a meta-analysis to assess comprehensively the association of the rs12220909 polymorphism with cancer risk.

METHODS

Relevant articles were collected by searching the databases of PubMed, Embase, Web of Science, China National Knowledge Infrastructure (CNKI), and WanFang. Data on rs12220909 in cancer patients and controls were extracted. Sensitivity analyses and publication bias assessments were performed.

RESULTS

Five studies with 3820 cases and 4574 controls were included in our meta-analysis. Pooled analyses showed that the rs12220909 polymorphism was not associated with cancer risk in any genetic model. (C vs G: odds ratio [OR] = 0.89, 95% confidence interval [CI] = 0.74-1.07; GC vs GG: OR = 0.83, 95% CI = 0.67-1.03; CC vs GG: OR = 1.06, 95% CI = 0.82-1.36; CC+GC vs GG: OR = 0.84, 95% CI = 0.69-1.03; CC vs GC+GG: OR = 1.10, 95% CI = 0.85-1.40).

CONCLUSIONS

Our results indicate that rs12220909 is not associated with cancer risk. Larger, well-designed multicenter studies are needed to further explore the association of miR-4293 rs12220909 polymorphism with cancer risk.

Whether miR-4293 rs12220909 variant affects cancer susceptibility: evidence from 11255 subjects

Background: miR-4293 rs12220909 polymorphism was reported associated with tumorigenesis, but the results are controversial. Thus, we planned to verify and obtain precise results.Methods: Databases were searched and reviewed up to November, 2019. Case-control studies which concern about the association between cancer risks and miR-4293 polymorphisms were all enrolled. The odds ratios (ORs) and 95% confidence intervals (CIs) calculated by the Z test were used to assess the underlying links. We also prospected how the miR-4293 impacts biological process through its target genes.Result: Finally, there are seven independent studies meet the enrolled criteria, along with 5147 cases and 6108 healthy controls. We revealed that there is a significant decrease effect of miR-4293 rs12220909 to cancer risks in heterozygote genetic model (BA vs. AA: OR = 0.857, p = .032), the similar results were also uncovered in PB control group, lung cancer and the studies conform to HWE. Results from GO items and KEGG pathway analysis illustrated that myeloid cell development, transcription factor complex, RNA polymerase II regulatory region DNA binding were regulated by miR-4293.Conclusion: In summary, our meta-analysis chase down heterozygote rs12220909 polymorphism of miR-4293 is a protective factor to cancer initiation, especially for lung cancer.

The role of microRNA-608 polymorphism on the susceptibility and survival of cancer: a meta-analysis

The role of rs4919510 polymorphism in microRNA-608 (miR-608) and cancer susceptibility and prognosis remain controversial and debatable. We conducted a meta-analysis of twenty-four eligible publications on the association of rs4919510 polymorphism with cancer risk and/or prognosis. Odds ratios, hazard ratios, and 95% confidence interval were used to investigate the association between this polymorphism and susceptibility, overall survival, and recurrence-free survival of cancer. Overall, eighteen case-control studies and nine cohort studies evaluated the susceptibility and prognostic value of rs4919510 polymorphism in cancer, respectively. Pooled analysis showed that rs4919510 polymorphism was not associated with cancer risk in all five genetic models. When stratifying by different cancer sites, rs4919510 polymorphism was detected to have a significant association with a decreased risk of colorectal cancer in homozygous model (P = 0.006) and recessive model (P = 0.001), subgroup analysis also emerged a weakened correlation between rs4919510 polymorphism and an increased risk of papillary thyroid cancer in heterozygote model (P = 0.04). Furthermore, the prognosis of rs4919510 variant in cancer patients showed that rs4919510 GG genotype was significant association with poor recurrence-free survival in homozygous models (P = 0.04). The meta-analysis suggested that the microRNA-608 rs4919510 polymorphism maybe associate with a significantly decreased risk for colorectal cancer. Further investigations on larger populations are required to evaluate and confirm this relationship.

MicroRNA-608 Promotes Apoptosis in Non-Small Cell Lung Cancer Cells Treated With Doxorubicin Through the Inhibition of TFAP4

Lung cancer is the most commonly diagnosed type of cancer and the leading cause of cancer-associated death worldwide. MicroRNAs (miRNAs) are non-coding single-stranded RNA molecules of ∼20–25 nucleotides in length. Single nucleotide polymorphisms are a class of genetic variation in the human genome, which when present in miRNA genes are associated with the risk of developing cancer. This study aimed to identify whether the miRNA (miR)-608 polymorphism rs4919510 influenced the incidence of lung cancer, and to explore the underlying mechanisms of miR-608 in the pathogenesis of the disease. A total of 37 patients with non-small cell lung cancer (NSCLC) were selected to determine the expression levels of miR-608; 96 NSCLC patients and 136 cancer-free healthy controls were recruited to determine the incidence of miR-608 rs4919510 in lung cancer patients. Additionally, the impact of miR-608 on the expression of predicted target genes, cell migration, viability, proliferation, and apoptosis was also assessed. We found that the presence of miR-608 rs4919510 did not affect the susceptibility of patients to NSCLC or the maturation of miR-608. miR-608 expression levels were found to be downregulated in NSCLC tissues. Furthermore, overexpression of miR-608 promoted doxorubicin-induced apoptosis in NSCLC cell lines A549 and HCC4006 by inhibiting the expression of transcription factor activating enhancer-binding protein 4 (TFAP4), and high expression levels of TFAP4 were observed in NSCLC tissues. Therefore, our results may provide valuable insights for the chemotherapeutical treatment of NSCLC.

Single Nucleotide Polymorphisms in miR-122 Are Associated with the Risk of Hepatocellular Carcinoma in a Southern Chinese Population

Single nucleotide polymorphisms (SNPs) in microRNA may affect its expression and regulation of target genes, which may consequently alter individual susceptibility to cancer. In this study we aimed to investigate associations between miR-122 polymorphisms and hepatocellular carcinoma (HCC) in a southern Chinese population. Three selected SNPs in miR-122 (rs9966765, rs1135519, and rs17669) were genotyped in 1050 HCC patients and 1079 cancer-free controls using Sequenom MassARRAY platform and the associations of the three SNPs and HCC risk were evaluated. We found that individuals with the rs1135519 CC genotypes had a significant increased risk of HCC than those with TT genotypes (adjusted OR=2.71, 95% CI=1.15-6.36, and P=0.022), while the rs9966765 CC genotypes showed a borderline significant association with increased risk of HCC when compared with the GG genotypes (adjusted OR=2.38, 95% CI=0.99-5.75, and P=0.052). There was also a significant increased risk of HCC when combining risk genotypes of these loci, i.e., rs1135519 CC and rs9966765 CC. Compared with the low-risk group (0 risk genotype), the high risk group (1-2 risk genotypes) had significantly increased risk of HCC (OR=1.61, 95% CI=1.05-2.44, and P=0.028). Further genotype-expression analysis revealed that cases carrying the CC genotype of rs1135519 had lower levels of miR-122 expression than those with the TT genotype. Our results suggest that SNP of rs1135519 modulates miR-122 expression and contributes to the genetic susceptibility of HCC, either independently or together with rs9966765 in miR-122. Further well-designed studies with lager sample sizes are needed to confirm our findings.

A polymorphism rs3746444 within the pre-miR-499 alters the maturation of miR-499-5p and its antiapoptotic function

microRNAs (miRNAs) are non‐coding RNAs that function as post‐transcriptional regulators of cardiac development and cardiovascular diseases. Single nucleotide polymorphisms (SNPs) in miRNA genes are a novel class of genetic variations in the human genome that confer the risk of cardiovascular diseases. Here, we identified a polymorphism A→G (rs3746444) in miR‐499 precursor (pre‐miR‐499) that affects the maturation of miR‐499‐5p and alters its antiapoptotic function by converting stable A‐U base pair to wobble G‐U base pair in pre‐miR‐499 secondary structure. Furthermore, our results showed that the concentrations of plasma miR‐499‐5p could be correlated with myocardial infarction (MI) and heart failure (HF) patients in comparison with control subjects and polymorphism rs3746444 in miR‐499 could influence its abundance in plasma. Finally, our results also showed that the variant of polymorphism in miR‐499 influenced the severity of the myocardial infarction significantly. This is the first report to highlight the biological significance of this polymorphism on the maturation of miR‐499‐5p and its antiapoptotic role during MI. These findings may pave a way to better understand the individual variability based on miRNA SNPs in heart diseases and may contribute to better treatment for disease severity on a personalized level.

MicroRNA-Related Polymorphisms in Infectious Diseases-Tiny Changes With a Huge Impact on Viral Infections and Potential Clinical Applications

MicroRNAs (miRNAs) are single-stranded sequences of non-coding RNA with approximately 22 nucleotides that act posttranscriptionally on gene expression. miRNAs are important gene regulators in physiological contexts, but they also impact the pathogenesis of various diseases. The role of miRNAs in viral infections has been explored by different authors in both population-based as well as in functional studies. However, the effect of miRNA polymorphisms on the susceptibility to viral infections and on the clinical course of these diseases is still an emerging topic. Thus, this review will compile and organize the findings described in studies that evaluated the effects of genetic variations on miRNA genes and on their binding sites, in the context of human viral diseases. In addition to discussing the basic aspects of miRNAs biology, we will cover the studies that investigated miRNA polymorphisms in infections caused by hepatitis B virus, hepatitis C virus, human immunodeficiency virus, Epstein–Barr virus, and human papillomavirus. Finally, emerging topics concerning the importance of miRNA genetic variants will be presented, focusing on the context of viral infectious diseases.

A Meta-Analysis of miR-499 rs3746444 Polymorphism for Cancer Risk of Different Systems: Evidence From 65 Case-Control Studies

MicroRNAs (miRNAs) are a class of endogenous, short and non-coding RNAs that may play important roles in the pathogenesis of tumor. The associations between microRNA-499 rs3746444 polymorphism and cancer risk in different systems remain inconclusive. This article is aimed to obtain more exact estimation of these relationships through a meta-analysis based on 52,456 individuals. We retrieved relevant and eligible studies from Pubmed and Embase database up to January 10, 2018. ORs and 95% CIs were used to estimate the associations between miR-499 polymorphism and cancer susceptibility in different systems. All analyses were performed using the Stata 11.0 software. A total of 65 case-control studies were retrieved using explicit inclusion and exclusion criteria. The study included 23,762 cases and 28,694 controls. Overall cancer analysis showed the association between miR-499 polymorphism and susceptibility to cancer was significant. MicroRNA-499 rs3746444 was found to be significantly associated with increased risk of cancer of the respiratory system (CC vs. TT: OR = 1.575, 95% CI = 1.268–1.955, CC vs. TC+TT: OR = 1.527, 95% CI = 1.232–1.892), digestive system (CC vs. TT: OR = 1.153, 95% CI = 1.027–1.295; TC vs. TT: OR = 1.109, 95% CI = 1.046–1.176; CC+TC vs. TT: OR = 1.112, 95% CI = 1.018–1.216; CC vs. TC+TT: OR = 1.137, 95% CI = 1.016–1.272; C vs. T: OR = 1.112, 95% CI = 1.025–1.206), urinary system (TC vs. TT: OR = 1.307, 95% CI = 1.130–1.512; CC+TC vs. TT: OR = 1.259, 95% CI = 1.097–1.446; C vs. T: OR = 1.132, 95% CI = 1.014–1.264), and gynecological system (C vs. T: OR = 1.169, 95% CI = 1.002–1.364). In the subgroup analysis by ethnicity, the result showed that significant association with an increased cancer risk was found in Asian. Subgroup analysis based on type of tumor was also performed, miR-499 rs3746444 is associated with susceptibility of cervical squamous cell carcinoma, lung cancer, prostate cancer, and hepatocellular carcinoma.

Association of miR-608 rs4919510 polymorphism and cancer risk: a meta-analysis based on 13,664 subjects

Single nucleotide polymorphisms (SNPs) in MicroRNAs (miRNAs) are involved in the mechanism of carcinogenesis. Several studies have evaluated the association of rs4919510 SNP in miR-608 with cancer susceptibility in different types of cancer, with inconclusive outcomes. To obtain a more precise estimation, we carried out this meta-analysis through systematic retrieval from the PubMed and Embase database. A total of 10 case-control studies were analyzed with 6,000 cases and 7,664 controls. The results showed that 4919510 SNP in miR-608 was significantly associated with decreased cancer risk only in recessive model (CC vs. GG+GC: OR=0.89, 95% CI: 0.82-0.97, P=0.009). By further stratified analysis, we found that rs4919510 SNP had some relationship with decreased cancer risk in both homozygote model (CC vs. GG: OR=0.59, 95% CI: 0.36-0.96, P=0.034) and dominant model (CG+ CC vs. GG: OR=0.60, 95% CI: 0.37-0.98, P=0.042) in Caucasians but no relationship in any genetic model in Asians. These results indicated that miR-608 rs4919510 polymorphism may contribute to the decreased cancer susceptibility and could be a promising target to forecast cancer risk for clinical practice. However, to further confirm these results, well-designed large scale case-control studies are needed in the future.

Association of single nucleotide polymorphisms in microRNAs with susceptibility to hepatitis B virus infection and HBV-related liver complications: A study in a Saudi Arabian population

The aim of this study was to evaluate the association of 10 SNPs in different microRNAs (miRNAs) with susceptibility to hepatitis B virus (HBV) infection, HBV clearance, persistence of chronic HBV infection, and progression to liver cirrhosis and hepatocellular carcinoma (HCC). Patients were categorized into the following groups: inactive HBV carrier, active HBV carrier, HBV-cleared subject and cirrhosis+HCC. Samples were analysed for 10 SNPs in microRNAs using either PCR-based genotyping or the TaqMan assay. We found that rs1358379 was associated with susceptibility to HBV infection, HBV clearance, persistent chronic HBV infection and liver cirrhosis+HCC. In addition, we found that rs2292832 and rs11614913 were associated with risk of HBV infection, viral clearance and cirrhosis+HCC, whereas rs2910164 was associated with proneness to HBV infection, and ability to clear the virus. There was evidence of associations between rs6505162 and HBV clearance and the development of liver disease, whereas a single association was found between rs2289030 and HBV clearance. Similarly, rs7372209 and rs4919510 were specifically associated with the development of HBV-induced liver complications. SNPs in miRNAs affect the susceptibility, clearance and progression of HBV infection in Saudi Arabian patients. We found, using Gene Ontology or pathway analyses, that these genes may contribute to the pathophysiology of HBV infection and related liver complications. However, differences in the association of examined SNPs with various clinical stages indicate variations in the respective functional roles of these polymorphisms and their miRNAs, and thus, further investigation to fully explore their therapeutic potential is warranted.

Genetic polymorphisms of non-coding RNAs associated with increased head and neck cancer susceptibility: a systematic review and meta-analysis

Genetic polymorphisms, including single nucleotide polymorphisms (SNP) and nucleotide repeat expansions, can occur in regions that transcribe non-coding RNAs (ncRNA), such as, but not limited to, micro RNA and long non-coding RNA. An association between genetic polymorphisms of ncRNA and increasing head and neck cancer (HNC) risk has been identified by several studies. Therefore, the aim of this systematic review is to consolidate existing findings to clarify this association. Four electronic databases, such as MEDLINE, EMBASE, Chinese BioMedical Literature Database, and China National Knowledge Infrastructure, were utilised. Inclusion of studies and data extraction were accomplished in duplicate. A total of 42 eligible studies were included, involving 28,527 cases and 37,151 controls. Meta-analysis, sensitivity analysis and publication bias detection were performed. Among the eligible studies, 102 SNPs were investigated, and 21 of them were considered eligible for meta-analysis. Our analysis revealed that HOTAIR rs920778, uc003opf.1 rs11752942, and miR-196a2 rs11614913 were related to HNC susceptibility, while let-7 rs10877887, miR-124-1rs531564, and miR-608 rs4919510 were considered as protective factors. In conclusion, our results showed the extreme importance of an up-to-date comprehensive meta-analysis encompassing the most recent findings to obtain a relevant and reliable framework to understand the relationship between ncRNA SNPs and HNC susceptibility.

Evaluation of a 3-base pair indel polymorphism within pre-microRNA-3131 in patients with prostate cancer using mismatch polymerase chain reaction-restriction fragment length polymorphism

The present study aimed to examine the impact of a 3-bp indel (rs57408770) polymorphism within the pre-microRNA (miR)-3131 polymorphism on prostate cancer (PCa) risk in a sample of an Iranian population. In total, 340 subjects, including 177 patients with PCa and 170 patients with benign prostatic hyperplasia, were enrolled in the present case-control study. A mismatch polymerase chain reaction-restriction fragment length polymorphism method was designed for genotyping the 3-bp indel (rs57408770) polymorphism. The present findings demonstrated that the indel variant significantly increased the risk of PCa in codominant [odds ratio (OR)=2.23, 95% confidence interval (CI)=1.13-4.37; P=0.021, insertion (ins)/ins vs. deletion (del)/del] and recessive (OR=2.33, 95% CI=1.25-4.36; P=0.009, ins/ins vs. del/del + del/ins). In conclusion, to the best of our knowledge, the present findings for the first time proposed that a 3-bp indel variant of miR-3131 may be a risk factor for susceptibility to PCa in a sample of an Iranian population. Further studies with different ethnicities and larger sample sizes are required to validate the present findings.

Associations between genetic variants located in mature microRNAs and risk of lung cancer

MiRNAs have been focused for their wide range of biological regulatory functions. Previous studies have suggested that individual miRNAs could influence tumorigenesis through their regulation of specific proto-oncogenes and tumor suppressor genes. This study was implemented to investigate the associations between SNPs in mature microRNAs (miRNAs) and development of lung cancer in a two-stage, case-control study, followed by some functional validations. First, 11 SNPs were analyzed in a case-control study of lung cancer, and the significant results were validated in an additional population. Our results showed that rs3746444 in mir-499 (allele C vs T: OR = 1.33; 95% CI = 1.15-1.54; P = 1.2 × 10-4) and rs4919510 in mir-608 (allele G vs C: OR = 1.27; 95% CI= 1.13-1.43; P = 5.1 × 10-5) were significantly associated with increased risk of lung cancer. Rs3746444 in mir-499 was also significantly associated with poor survival of lung cancer (HR, 1.35; 95% CI, 1.15-1.58; P = 0.0002). The expression levels of mir-499 and mir-608 were significantly lower than those of adjacent normal tissues (P < 0.0005), and the carriers of minor alleles have lower expression levels of mir-499 and mir-608 than those of major alleles (P < 0.001). These findings indicated that rs3746444 in mir-499 and rs4919510 in mir-608 might play a substantial role in the susceptibility to lung cancer.

miR-492G>C polymorphism (rs2289030) is associated with overall survival of hepatocellular carcinoma patients

Single-nucleotide polymorphisms (SNPs) of microRNAs (miRNAs) are considered potential markers of cancer risk and prognosis in various cancers. In the current study, the primary aim is to determine whether the miR-492G>C polymorphism (rs2289030) altered hepatocellular carcinoma (HCC) prognosis. The SNP rs2289030 of miR-492 was genotyped using DNA from blood samples of 362 HCC patients that had undergone surgical resection of a HCC tumor. The associations between overall survival and demographic characteristics, clinical features, and the SNP rs2289030 were estimated using the Cox proportional hazards model. Results showed that patients who carried the CG genotype (P  = 0.015, hazard ratio [HR] = 0.704, 95 % confidence interval [CI] 0.530-0.934) and CG+GG genotype (P = 0.011, HR = 0.703, 95 % CI 0.536-0.924) had significantly decreased risk of death compared to those with the CC genotype. Similar results were found in the multivariate analysis adjusted by tumor size and venous invasion. Further stratification analysis indicated that the effect of rs2289030 had more prominence in patients ≤50 years old and that reported ever using alcohol, male gender, a family history of HCC, being HbsAg or alpha fetoprotein (AFP) positive, differentiation I + II, presence of venous invasion or cirrhosis, multiple tumors, and pTNM stage I + II. Results from this study illustrate the potential use of miR-492 rs2289030 as a prognostic marker for HCC patients that have undergone a surgical resection of the tumor.

MicroRNA-608 acts as a prognostic marker and inhibits the cell proliferation in hepatocellular carcinoma by macrophage migration inhibitory factor

Human hepatocellular carcinoma (HCC) is one of the most prevalent malignancies in the world. Research on HCC has recently focused on microRNAs (miRNAs) that play crucial roles in cancer development and progression of HCC. In this study, we aimed to analyze the expression and function of a metastasis-associated microRNA-608 (miR-608) in HCC. Samples of human HCC and matched adjacent normal tissues were surgically removed, and miR-608 expression and the pathological characteristics of HCC were investigated. In this study, we found that miR-608 expression was significantly reduced in HCC and its expression levels were highly associated with tumor size, differentiation, clinical stage, and overall and disease-free survival of HCC. Overexpression of miR-608 in HCC cell lines HepG2 and SK-Hep-1 inhibited cell proliferation by G1 arrest. Macrophage migration inhibitory factor (MIF), a potential target gene of miR-608, was inversely correlated with miR-608 expression in HCC tissues and cell lines. Furthermore, we demonstrated that MIF was directly regulated by miR-608 and the restoration of MIF expression reversed the inhibitory effects of miR-608 on HCC cell proliferation. Taken together, these findings collectively demonstrate that miR-608 exerts its anti-cancer function by directly targeting MIF in HCC, indicating a potential novel prognostic biomarker and therapeutic target for HCC.