Mulong Du

Circulating miR-497 and miR-663b in plasma are potential novel biomarkers for bladder cancer

MicroRNAs (miRNAs), abundant and highly stable in the plasma, have been widely reported. This greatly pursued us to investigate whether plasma miRNAs could be considered as powerful biomarkers for diagnosing bladder cancer (BC). We performed a plasma miRNAs profile with the TaqMan Low Density Array, and a two-phase validation to detect the candidate miRNAs expression by quantitative PCR. The receiver operating characteristic curve (ROC) and the area under curve (AUC) were used to evaluate diagnostic accuracy. A total of eight plasma miRNAs abnormally expressed between BC patients and healthy controls in microarray analysis (i.e., elevated miRNAs for miR-505, miR-363 and miR-663b, and decreased for miR-99a, miR-194, miR-100, miR-497 and miR-1 in BC plasma). In further independent cohorts, miR-497 and miR-663b with significantly differential expression were confirmed. Moreover, the AUC, sensitivity and specificity were raised to 0.711 (95% CI = 0.641-0.780), 69.7% and 69.6%, respectively, when miR-497 and miR-663b were integrated. This is the first study systematically exploring the existence of specific plasma miRNAs as early diagnostic biomarkers for BC in Chinese population; and these findings supported that plasma miR-497 and miR-663b could be promising novel circulating biomarkers in clinical detection of BC.

The association analysis of lncRNA HOTAIR genetic variants and gastric cancer risk in a Chinese population.

The HOX transcript antisense intergenic RNA (HOTAIR), a well-known long noncoding RNA, is involved in pathogenesis and progress of multiple tumors. Its ectopic expression and biological functions have been observed in gastric cancer. In this study, we conducted a two-stage case-control study to evaluate whether genetic variations of HOTAIR were associated with gastric cancer risk. We identified that a single nucleotide polymorphism (SNP) rs4759314 was significantly associated with the increased gastric cancer risk with an odds ratio (OR) of 1.39 [95% confidence interval (CI) = 1.13–1.71, P = 0.002] in the combined sets. Further functional experiments revealed the allele-specific effects on HOTAIR and HOXC11 expressions in gastric cancer tissues, of which HOTAIR and HOXC11 expressions of individuals carrying with AG genotype were much higher than those with AA genotype; similarly, the effects occurred in intronic promoter activities, of which the promoter activity of G allele was more pronounced than that of A allele. Interestingly, we identified a novel potential oncogene HOXC11 in gastric cancer pathogenesis with differential expression in gastric cancer tissues by association analysis with candidate gene strategy. These results suggest that SNP rs4759314 of HOTAIR acts as a potential biomarker for predicting gastric cancer, and the role of HOXC11 in gastric cancer etiology is warranted to further investigation.

Genome-wide analysis of long noncoding RNA signature in human colorectal cancer.

Long noncoding RNAs (lncRNAs) have been widely regarded as crucial regulators in various biological processes involved in carcinogenesis. However, the comprehensive lncRNA expression signature in colorectal cancer remains fully unknown. We performed a high throughput microarray assay to detect lncRNA expression profile in three paired human colorectal cancer tissues and their adjacent normal tissues. Additional 90 paired colorectal samples were collected to verify differently expression levels of two selected lncRNAs using q-RT-PCR assay. Bioinformatic approaches were performed to explore into the functions of these differently expressed lncRNAs. Microarray assay showed a series of lncRNAs were differently expressed in colorectal cancer. Two of the lncRNAs, HOTAIR and a novel lncRNA, lncRNA-422 were confirmed in more samples (P=0.015 for HOTAIR and P=0.027 for lncRNA-422, respectively). GSEA indicated that gene sets most correlated with them were those named up-regulated in KRAS-over, down-regulated in JAK2-knockout, down-regulated in PDGF-over and down-regulated in TBK1-knockout, all of which were cancer-related. Subsequently, GO analyses of most significantly correlated coding genes of HOTAIR and lncRNA-422 showed that these two lncRNAs may participate in carcinogenesis by regulating protein coding genes involved in special biological process relevant to cancer. Our study demonstrated that different lncRNA expression patterns were involved in colorectal cancer. Besides, HOTAIR and lncRNA-422 were identified to participate in colorectal cancer. Further studies into biological mechanisms of differently expressed lncRNAs identified in our study will help to provide new perspective in colorectal cancer pathogenesis.

Genetic variations in microRNAs and the risk and survival of renal cell cancer

MicroRNAs (miRNAs) are a class of short non-coding, single-stranded RNAs, which perform posttranscriptional regulatory functions as tumor suppressors or oncogenes. Single nucleotide polymorphisms (SNPs) in microRNAs (miRNAs) genes are currently being identified for contributing to cancer risk, prognosis and survival. We investigated whether genetic variations of miRNAs were associated with the risk and prognosis of renal cell carcinoma (RCC). We genotyped four common miRNA SNPs (i.e. miR-146a rs2910164, miR-149 rs2292832, miR-196a2 rs11614913 and miR-499 rs3746444) to assess their associations with RCC risk in a two-stage case-control study (355 cases and 362 controls in discovery set, meanwhile 647 cases and 660 controls in validation set), as well as RCC survival in 311 patients. We found that the miR-196a2 SNP rs11614913 was associated with RCC susceptibility in recessive model [CC versus TT/TC, adjusted odds ratio = 0.65, 95% confidence interval (CI) = 0.52-0.83] and with survival of RCC in dominant model (TC/CC versus TT, adjusted hazard ratio = 0.40, 95% CI = 0.18-0.89). Meanwhile, the rs11614913 CC genotype was associated with the significantly decreased expression of miR-196a-5p in 26 renal cancer tissues (P = 0.018). Moreover, luciferase reporter assays revealed the potential effect of rs11614913 SNP on the binding of miR-196a-3p to its targets. These results suggested that the miR-196a2 rs11614913 may contribute to the genetic susceptibility and prognosis for RCC, which may act as a biomarker for RCC occurrence and prognosis.

Genetic Variation in DROSHA 3’UTR Regulated by hsa-miR-27b Is Associated with Bladder Cancer Risk

Purpose miRNAs can regulate the biological processes, including differentiation, proliferation and apoptosis. DICER and DROSHA are two members of RNase III family, playing pivotal roles in the pathway of miRNAs biogenesis. In this study, we hypothesized that genetic variations of the DICER and DROSHA genes were associated with the bladder cancer risk. Experimental Design We performed a case-control study of 685 bladder cancer cases and 730 controls to investigate the association between the seven functional SNPs of DICER and DROSHA genes and bladder cancer risk. We then evaluated the functionality of the important SNPs. Results We found that rs10719T>C polymorphism located in 3’ untranslated region (UTR) of DROSHA gene was associated with the increased risk of bladder cancer. Stratified analysis suggested that rs10719TC/CC genotype can increase risk of bladder cancer among male patients (Adjusted OR = 1.34, 95% CI = 1.05-1.70, P = 0.018), and ever smokers (1.56, 1.14-2.14, 0.006), compared with TT genotype. Furthermore, DROSHA rs10719T>C polymorphism was predicted to regulate the binding activity of hsa-miR-27a/b. Luciferase reported gene assay confirmed that rs10719 T to G substitution disrupted the binding site for hsa-miR-27b, resulting the increased levels of DROSHA protein. Conclusions Taken together, these findings suggested that DROSHA rs10719T>C polymorphism may be associated with bladder cancer risk in a Chinese population, and hsa-miR-27b can influence the expression of DROSHA protein by binding with 3’UTR.

Clinical potential role of circulating microRNAs in early diagnosis of colorectal cancer patients

Current procedures for diagnosis and biomarker examination of colorectal cancer (CRC) are invasive and unpleasant. There is a great need to identify sensitive and specific biomarkers for early diagnosis of CRC. Circulating microRNAs (miRNAs) are promising molecular markers for CRC prediction. We performed a comprehensive meta-analysis to integrate an evaluation index for diagnostic accuracy of circulating miRNAs in diagnosing CRC patients. Furthermore, we conducted an independent validation set of 49 CRC patients and 49 healthy controls. In our meta-analysis, we found that miR-21 yielded a pooled area under ROC curve (AUC) of 0.867 (sensitivity: 76%, specificity: 82%) in discriminating CRC from controls, and miR-92a yielded a summary AUC of 0.803 (sensitivity: 77%, specificity: 68%); miR-21 had a higher diagnostic efficiency than miR-92a. In the further validation, plasma miR-21 levels in CRC patients were significantly higher than levels observed in healthy subjects. A ROC curve analysis showed a consistent result. However, this phenotype was not present in miR-92a. Moreover, the expression trend of miR-21 in plasma samples was in line with that of tissue samples, along with the cellular level. Current evidences suggest that plasma miR-21 could be a reliable and non-invasive biomarker for CRC diagnosis. Studies with larger cohorts that include the diagnostic value of plasma miR-21 for CRC are warranted.

Folic acid supplements and colorectal cancer risk: meta-analysis of randomized controlled trials

Numerous studies have investigated the effects of folic acid supplementation on colorectal cancer risk, but conflicting results were reported. We herein performed a meta-analysis based on relevant studies to reach a more definitive conclusion. The PubMed and Embase databases were searched for quality randomized controlled trials (RCTs) published before October 2014. Eight articles met the inclusion criteria and were subsequently analyzed. The results suggested that folic acid treatment was not associated with colorectal cancer risk in the total population (relative risk [RR] = 1.00, 95% confidence interval [CI] = 0.82–1.22, P = 0.974). Moreover, no statistical effect was identified in further subgroup analyses stratified by ethnicity, gender, body mass index (BMI) and potential confounding factors. No significant heterogeneity or publication bias was observed. In conclusion, our meta-analysis demonstrated that folic acid supplementation had no effect on colorectal cancer risk. However, this finding must be validated by further large studies.

Genetic variants in lncRNA H19 are associated with the risk of bladder cancer in a Chinese population

The long non-coding RNA (lncRNA) H19 as an imprinted gene transcribed from only the maternal allele has the vital role in carcinogenesis. Aberrant H19 expression is involved in bladder cancer development. In this study, we explored the association between single nucleotide polymorphisms (SNPs) in H19 and bladder cancer risk. Four tagging SNPs (tagSNPs) were selected from the 1000 Genomes Project database. In total, 1049 bladder cancer cases and 1399 controls were recruited in this case-control study. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were calculated by using unconditional univariate and multivariate logistic regression models to evaluate associations between the H19 tagSNPs genotypes and risk of bladder cancer. We found a statistically significant increased risk of bladder cancer in the carriers of the rs217727 AA genotype compared with carriers of GG/GA genotype (OR = 1.31, 95% CI = 1.03-1.67). The subsequently stratified analyses also revealed that the H19 rs217727 AA genotype remarkably elevated the risk of bladder cancer in subgroups of young subjects (OR = 1.80, 95% CI = 1.16-2.81), males (OR = 1.44, 95% CI = 1.10-1.89) and smokers (OR = 1.55, 95% CI = 1.06-2.27), as well as high tumour grade (OR = 1.89, 95% CI = 1.23-2.91) and invasive disease (OR = 1.62, 95% CI = 1.01-2.60). This finding indicates that the rs217727 polymorphism is significantly associated with the risk of bladder cancer.

Hsa-miR-196a2 polymorphism increases the risk of acute lymphoblastic leukemia in Chinese children

Acute lymphoblastic leukemia (ALL) is a major cause of mortality and morbidity in childhood, and the causes of ALL are not completely understood. microRNAs (miRNAs) regulate various biological processes including organ development, cell growth regulation, cell differentiation, apoptosis, and tumorigenesis. We performed a case-control study with 570 childhood ALL cases and 673 cancer-free controls to investigate the association between hsa-miR-196a2 rs11614913 T>C polymorphism and ALL risk. The bioinformatics was used to estimate the potential target of hsa-miR-196a2. In the present study, the hsa-miR-196a2 variant TC heterozygote, and CC/TC genotypes were found to be associated with a significantly increased childhood ALL risk, compared with the TT wild-type homozygote (adjusted OR=1.50, 95% CI=1.15-1.95 for TC and OR=1.40, 95% CI=1.09-1.79 for CC/TC). Further, the difference was pronounced in younger (≤6) subjects or parental non-drinker. The significance of the increased risk is more obvious than the higher treatment branch. Additionally, we found that the rs11614913 TC genotype can increase B-phenotype ALL risk (OR=1.37, 95% CI=1.07-1.76). Finally, combination of three bioinformatics approaches revealed that HOXC8 may be the target gene of hsa-miR-196a2. Taken together, our finding suggested that hsa-miR-196a2 rs11614913 T>C may increase the risk of childhood ALL. Large studies with the function of hsa-miR-196a2 are needed in the further study.

Association of genetic variants in lncRNA H19 with risk of colorectal cancer in a Chinese population

Objective The long non-coding RNA (lncRNA) gene, H19, has been involving in multiple biological functions, which also plays a vital role in colorectal cancer carcinogenesis. However, the association between genetic variants in H19 and colorectal cancer susceptibility has not been reported. In this study, we aim to explore whether H19 polymorphisms are related to the susceptibility of colorectal cancer. Methods We conducted a case-control study to evaluate the association between four selected single nucleotide polymorphisms (SNPs) (rs2839698, rs3024270, rs217727, and rs2735971) in H19 and the risk of colorectal cancer in a Chinese population. Results We found that individuals with rs2839698 A allele had a significantly increased risk of colorectal cancer, compared to those carrying G allele [odds ratio (OR) = 1.20, 95% confidence interval (CI) = 1.05–1.36 in additive model]. Further stratified analyses revealed that colon tumor site, well differentiated grade and Dukes stage of C/D were significantly associated with colorectal cancer risk (P < 0.05). Additionally, bioinformatic analysis showed that rs2839698 may change the crucial folding structures and alter the target microRNAs of H19. Conclusions Our results provided the evidence that rs2839698 in H19 was associated with elevated risk of colorectal cancer, which may be a potential biomarker for predicting colorectal cancer susceptibility.