Yuqiu Ge

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.

Short-term effects of ambient air pollution and childhood lower respiratory diseases

The association between air pollution and childhood respiratory disease is inconsistent. In the present study, we investigated a short-term effect of ambient air pollutants and daily childhood lower respiratory diseases (CLRD). Daily air pollutants, weather data, and CLRD data were collected from January 2014 to April 2015 (452 days) in Nanjing, China. Time-series regression and generalized additive models were used to assess the effects of air pollutants (PM10, PM2.5, NO2, SO2, O3, and CO) on CLRD. We observed that an interquartile range (IQR) increase in concentrations of PM10, NO2, and SO2 significantly increased the daily CLRD with 6 days cumulative effects (difference of estimates: 2.8%, 95% CI: 0.6–5.0%; 4.1%, 1.2–7.0%; 5.6%, 2.6–8.6%, respectively). However, no significant association was found in IQR concentrations of PM2.5, O3, and CO. Specifically, elevated PM10, PM2.5, NO2, and SO2 significantly increased the numbers of CLRD in cool season (3.6%, 1.5–5.7%; 2.4%, 0.3–4.5%; 4.9%, 2.9–7.0%; 6.3%, 3.7–9.0%, respectively). Additionally, the effect estimates of PM10, NO2, and SO2 in female and age >27 months were more pronounced than in male and age ≤27 months. This study suggested that short-term exposure to ambient PM10, NO2, and SO2 were associated with the increased CLRD numbers.

Rare variants in BRCA2 and CHEK2 are associated with the risk of urinary tract cancers

Previous studies have shown that two rare variants, rs11571833 in BRCA2 and rs17879961 in CHEK2 were associated with lung cancer. However, the associations between these two variants and urinary tract cancers risk remain largely unexplored. We applied imputation of three genome-wide association studies published in the database of Genotypes and Phenotypes (dbGaP). Unconditional logistic regression analysis and meta-analysis were performed to assess the association between these two variants and the risk of urinary tract cancers. Our results showed that rs11571833[T] had an effect on urinary tract cancers predisposition (ORmeta = 1.45, Pmeta = 0.013), especially associated with increased the risk of bladder cancer (ORmeta = 1.60, Pmeta = 0.010). Moreover, rs17879961[C] had a protective effect on the urinary tract cancers (ORmeta = 0.67, Pmeta = 1.0 × 10−3) and was mostly associated with a lower incidence of renal cell carcinoma (ORmeta = 0.51, Pmeta = 2.0 × 10−3). Together, our study indicates that BRCA2 and CHEK2 play an important role in the genetic susceptibility to urinary tract cancers.

The association analysis of hOGG1 genetic variants and gastric cancer risk in a Chinese population.

Human 8-oxoguanine DNA glycosylase (hOGG1) is known to play an important role in the prevention of carcinogenesis, including gastric cancer (GC). We performed a case-control study to investigate whether single nucleotide polymorphisms (SNPs) of hOGG1 are associated with GC risk in a Chinese population. Two potential functional tagSNPs (rs159153 and rs1052133) and a previously reported risk SNP (rs125701) were genotyped in 1,275 GC patients and 1,436 controls. We found that SNP rs125701 G > A was significantly associated with the increased GC risk [adjusted odds ratio (OR) = 1.38, 95% confidence interval (CI) = 1.05-1.79 in additive model]. Besides, the functional studies demonstrated that the minor A allele of rs125701 significantly reduced the transcriptional activity of hOGG1 promoter and enhanced the methylation level of CpG site of cg15357639. In conclusion, our results suggested that the SNP rs125701 in hOGG1 promoter was associated with the elevated GC risk, which could act as a new potential biomarker for GC susceptibility. Further functional verification of rs125701 in GC pathogenesis is warranted.

KCNMA1 cooperating with PTK2 is a novel tumor suppressor in gastric cancer and is associated with disease outcome

BackgroundInactivation of tumor suppressor genes by promoter hypermethylation plays a key role in the tumorgenesis. It is necessary to uncover the detailed pattern of whole genome-wide abnormal DNA methylation during the development of gastric cancer (GC).MethodWe performed a genome-wide methylation detection using 12 paired of GC tissues and their corresponding normal tissues. Methylation-specific PCR (MSP) and bisulphite sequencing (BSP) were used to measure methylation status of specific CpG site. Based on the bioinformatic analysis, the cell phenotypes and mouse model experiments were constructed to detect effect of the target gene. Using the Kaplan–Meier survival curve, the clinical value of KCNMA1 was assessed in GC patients.ResultsThe CpG site cg24113782 located at the promoter of KCNMA1 showed the most significant difference, contributing to the commonly silenced KCNMA1in gastric cancer cells and primary GC tissues. The promoter methylation of KCNMA1 was detected in 68.7% (77/112) of tumor tissues, compared with 16.2% (18/112) of normal tissues (P < 0.001). The survival curve indicated that KCNMA1 hypermethylation was significantly associated with the shortened survival in GC patients (P = 0.036). KCNMA1 significantly inhibited biological malignant behavior of gastric cancer cell by inducing cell apoptosis in vitro, and suppressed xenograft tumor growth in subcutaneous mouse models (both P < 0.001). Furthermore, the anti-tumor effect of KCNMA1was mediated through suppressing the expression of PTK2.ConclusionKCNMA1 is a critical tumor suppressor in gastric carcinogenesis and its hypermethylation is an independent prognostic factor in patients with gastric cancer.

Evaluation of genome-wide genotyping concordance between tumor tissues and peripheral blood

Tumor tissues were potential resources in cancer susceptibility studies. To assess the genotyping concordance between tumor tissues and peripheral blood, we conducted this study in a large sample size and genome-wide scale. Genome-wide genotypes of human colon adenocarcinoma (COAD) retrieved from The Cancer Genome Atlas (TCGA) was analyzed. A total of 387 pairs of matched fresh frozen tumor tissues and peripheral blood samples passed the quality control processes. High concordant rate (94.85% with no-calls and 97.89% without no-calls) was found between tumor tissues and peripheral blood. The discordant rate raised with the increase of heterozygote rate, and the tendency was statistically significant. The total missing rate was 3.10%. We also verified 14 susceptibility SNPs and the average genotyping concordant rate was 97.42%. These findings suggest that majority of SNPs could be accurately genotyped using DNA isolated from tumor tissues.

The association of rs710886 in lncRNA PCAT1 with bladder cancer risk in a Chinese population.

OBJECTIVE The long noncoding RNA PCAT1 is an important gene involved in urinary tumors. In this study, we aimed to explore the association between polymorphisms in PCAT1 and bladder cancer susceptibility. METHODS A two-stage case-control study was conducted to assess the association between four tagging SNPs (i.e., rs4871771, rs1902432, rs16901904 and rs710886) and bladder cancer risk. Odds ratios (ORs) and their 95% confidence intervals (CIs) were calculated with unconditional univariate and multivariate logistic regression. RESULTS At the first stage of discovery, we identified that SNP rs710886A>G was significantly associated with bladder cancer risk (OR=0.86, 95% CI=0.74-0.99, P=0.046). At the following stage of validation, individuals with GG genotype were found to have a significant reduction in bladder cancer risk compared with those carrying AA genotype (adjusted OR=0.83, 95% CI=0.74-0.93, P=0.001). Furthermore, stratified analyses showed that protective effect of rs710886 was more pronounced in subgroup of age>60 and never smoking, and had little to do with sex. Besides, rs710886 was identified as an eQTL for PCAT1. G allele was consistent with lower PCAT1 expression. CONCLUSION This study indicates that genetic variants in lncRNA PCAT1 were associated with bladder cancer susceptibility and the SNP rs710886 may act as a potential biomarker for bladder cancer risk.

Functional annotation of colorectal cancer susceptibility loci identifies MLH1 rs1800734 associated with MSI patients

Recently, we read the article by Ma et al with great interest. They conducted a comprehensive meta-analysis that nominated 62 variants in 50 candidate genes with high level of cumulative evidence for genetic susceptibility to colorectal cancer (CRC).1 Interestingly, the authors found that 10 variants in 7 genes were graded strong and moderate association with CRC risk. However, functional annotations of these variants remain largely unknown. To investigate their functional relevance, we annotated the variants and their high related single nucleotide polymorphisms (SNPs) (linkage disequilibrium, r2>0.9) using publicly available The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus datasets. After exclusion of the variants with minor allele frequency <0.05, a total of four SNPs (rs1801155, rs1569686, rs1800734 and rs2736100) were included in further analysis (table 1). We then evaluated the effect of risk alleles on gene epigenetic and expression alterations in CRC tumour tissues from TCGA. Three SNPs (rs1569686, rs1800734 and rs2736100) were identified as methylation quantitative trait loci (meQTL) in the 500 kb upstream and …

LncRNA MT1JP functions as a ceRNA in regulating FBXW7 through competitively binding to miR-92a-3p in gastric cancer

BackgroundEmerging evidence has shown that dysregulation function of long non-coding RNAs (lncRNAs) implicated in gastric cancer (GC). However, the role of the differentially expressed lncRNAs in GC has not fully explained.MethodsLncRNA expression profiles were determined by lncRNA microarray in five pairs of normal and GC tissues, further validated in another 75 paired tissues by quantitative real-time PCR (qRT-PCR). Overexpression of lncRNA MT1JP was conducted to assess the effect of MT1JP in vitro and in vivo. The biological functions were demonstrated by luciferase reporter assay, western blotting and rescue experiments.ResultsLncRNA MT1JP was significantly lower in GC tissues than adjacent normal tissues, and higher MT1JP was remarkably related to lymph node metastasis and advance stage. Besides, GC patients with higher MT1JP expression had a well survival. Functionally, overexpression of lncRNA MT1JP inhibited cell proliferation, migration, invasion and promoted cell apoptosis in vitro, and inhibited tumor growth and metastasis in vivo. Functional analysis showed that lncRNA MT1JP regulated FBXW7 expression by competitively binding to miR-92a-3p. MiR-92a-3p and down-regulated FBXW7 reversed cell phenotypes caused by lncRNA MT1JP by rescue analysis.ConclusionMT1JP, a down-regulated lncRNA in GC, was associated with malignant tumor phenotypes and survival of GC. MT1JP regulated the progression of GC by functioning as a competing endogenous RNA (ceRNA) to competitively bind to miR-92a-3p and regulate FBXW7 expression. Our study provided new insight into the post-transcriptional regulation mechanism of lncRNA MT1JP, and suggested that MT1JP may act as a potential therapeutic target and prognosis biomarker for GC.

LncRNA PCAT1 and its genetic variant rs1902432 are associated with prostate cancer risk

Emerging evidence has showed that lncRNAs and trait-associated loci in lncRNAs play a crucial role in the progression of cancer including prostate cancer (PCa).This study aimed to investigate the molecular mechanisms of lncRNA PCAT1 involved in PCa development and its genetic variant associated with PCa risk. We applied cell proliferation and apoptosis assays to assess the effect of PCAT1 on PCa cell phenotypes. In addition, the genome-wide profiling of gene expression was assessed from three pairs of DU145 cells transfected with PCAT1 overexpression vector or negative control (NC) vector. Furthermore, a case-control study was conducted to explore the associations of four tagging single nucleotide polymorphisms (tagSNPs) and PCa risk in 850 PCa cases and 860 cancer-free controls. Our results showed that lncRNA PCAT1 promoted cell proliferation and inhibited cell apoptosis. Ingenuity pathway analysis (IPA) indicated that dysregulated mRNAs induced by overexpression of PCAT1 were primarily enriched in androgen-independent prostate tumor term and implicated in the disease and functions networks, such as cell death and survival, cell proliferation and gene expression. Besides, rs1902432 in PCAT1 was significantly associated with increased risk of PCa (Additive model: OR = 1.19, P = 0.014; Co-dominant model: CC vs. TT, OR = 1.45, P =0.012; Recessive model: CC vs. TT/CT, OR= 1.34, P = 0.027). This study suggests that PCAT1 may act as an oncogene through promoting cell proliferation and suppressing cell apoptosis in PCa development, and genetic variant in PCAT1 contributes to the susceptibility to PCa.