Jiaping Chen

Genetic variants of miRNA sequences and non–small cell lung cancer survival

Recent evidence indicates that small noncoding RNA molecules known as microRNAs (miRNAs) can function as tumor suppressors and oncogenes. Mutation, misexpression, and altered mature miRNA processing are implicated in carcinogenesis and tumor progression. Because SNPs in pre-miRNAs could alter miRNA processing, expression, and/or binding to target mRNA, we conducted a systematic survey of common pre-miRNA SNPs and their surrounding regions and evaluated in detail the association of 4 of these SNPs with the survival of individuals with non-small cell lung cancer (NSCLC). When we assumed that disease susceptibility was inherited as a recessive phenotype, we found that the rs11614913 SNP in hsa-mir-196a2 was associated with survival in individuals with NSCLC. Specifically, survival was significantly decreased in individuals who were homozygous CC at SNP rs11614913. In the genotype-phenotype correlation analysis of 23 human lung cancer tissue samples, rs11614913 CC was associated with a statistically significant increase in mature hsa-mir-196a expression but not with changes in levels of the precursor, suggesting enhanced processing of the pre-miRNA to its mature form. Furthermore, binding assays revealed that the rs11614913 SNP can affect binding of mature hsa-mir-196a2-3p to its target mRNA. Therefore, the rs11614913 SNP in hsa-mir-196a2 may be a prognostic biomarker for NSCLC. Further characterization of miRNA SNPs may open new avenues for the study of cancer and therapeutic interventions.

Common genetic variants in pre-microRNAs were associated with increased risk of breast cancer in Chinese women.

Small, noncoding RNA molecules, called microRNAs (miRNAs), are thought to function as either tumor suppressors or oncogenes. Common single‐nucleotide polymorphisms (SNPs) in miRNAs may change their property through altering miRNA expression and/or maturation, and thus they may have an effect on thousands of target mRNAs, resulting in diverse functional consequences. However, it remains largely unknown whether miRNA SNPs may alter cancer susceptibility. We evaluated the associations of selected four SNPs (rs2910164, rs2292832, rs11614913, and rs3746444) in pre‐miRNAs (hsa‐mir‐146a, hsa‐mir‐149, hsa‐mir‐196a2, and hsa‐mir‐499) with breast cancer risk in a case‐control study of 1,009 breast cancer cases and 1,093 cancer‐free controls in a population of Chinese women and we found that hsa‐mir‐196a2 rs11614913:T>C and hsa‐mir‐499 rs3746444:A>G variant genotypes were associated with significantly increased risks of breast cancer (odds ratio [OR], 1.23; 95% confidence interval [CI], 1.02–1.48 for rs11614913:T>C; and OR, 1.25; 95% CI, 1.02–1.51 for rs3746444:A>G in a dominant genetic model) in a dose‐effect manner (P for trend was 0.010 and 0.037, respectively). These findings suggest, for the first time, that common SNPs in miRNAs may contribute to breast cancer susceptibility. Further functional characterization of miRNA SNPs and their influences on target mRNAs may provide underlying mechanisms for the observed associations and disease etiology. Hum Mutat 0, 1–6, 2008.

A genome-wide association study identifies two new lung cancer susceptibility loci at 13q12.12 and 22q12.2 in Han Chinese

Lung cancer is the leading cause of cancer-related deaths worldwide. To identify genetic factors that modify the risk of lung cancer in individuals of Chinese ancestry, we performed a genome-wide association scan in 5,408 subjects (2,331 individuals with lung cancer (cases) and 3,077 controls) followed by a two-stage validation among 12,722 subjects (6,313 cases and 6,409 controls). The combined analyses identified six well-replicated SNPs with independent effects and significant lung cancer associations (P < 5.0 × 10−8) located in TP63 (rs4488809 at 3q28, P = 7.2 × 10−26), TERT-CLPTM1L (rs465498 and rs2736100 at 5p15.33, P = 1.2 × 10−20 and P = 1.0 × 10−27, respectively), MIPEP-TNFRSF19 (rs753955 at 13q12.12, P = 1.5 × 10−12) and MTMR3-HORMAD2-LIF (rs17728461 and rs36600 at 22q12.2, P = 1.1 × 10−11 and P = 6.2 × 10−13, respectively). Two of these loci (13q12.12 and 22q12.2) were newly identified in the Chinese population. These results suggest that genetic variants in 3q28, 5p15.33, 13q12.12 and 22q12.2 may contribute to the susceptibility of lung cancer in Han Chinese.

A genome-wide association study identifies new susceptibility loci for non-cardia gastric cancer at 3q13.31 and 5p13.1

Gastric cancer, including the cardia and non-cardia types, is the second leading cause of cancer-related deaths worldwide. To identify genetic risk variants for non-cardia gastric cancer, we performed a genome-wide association study in 3,279 individuals (1,006 with non-cardia gastric cancer and 2,273 controls) of Chinese descent. We replicated significant associations in an additional 6,897 subjects (3,288 with non-cardia gastric cancer and 3,609 controls). We identified two new susceptibility loci for non-cardia gastric cancer at 5p13.1 (rs13361707 in the region including PTGER4 and PRKAA1; odds ratio (OR) = 1.41; P = 7.6 × 10−29) and 3q13.31 (rs9841504 in ZBTB20; OR = 0.76; P = 1.7 × 10−9). Imputation analyses also confirmed previously reported associations of rs2294008 and rs2976392 on 8q24, rs4072037 on 1q22 and rs13042395 on 20p13 with non-cardia gastric cancer susceptibility in the Han Chinese population.

Functional variant in microRNA-196a2 contributes to the susceptibility of congenital heart disease in a Chinese population†

Hox gene clusters play an important role during cardiac septation to valve formation in different species, and the miR‐196a‐HOXB8‐Sonic hedgehog signaling pathway is of particular interest. Recently, we found that a genetic variant of rs11614913 in the miR‐196a2 sequence could alter mature miR‐196a expression and target mRNA binding; this observation led us to hypothesize that rs11614913 might influence susceptibility to sporadic congenital heart disease (CHD). We conducted a three‐stage case–control study of CHD in Chinese to test our hypothesis by genotyping miR‐196a2 rs11614913 and three other pre‐miRNA SNPs (miR‐146a rs2910164, miR‐149 rs2292832, and miR‐499 rs3746444) in 1,324 CHD cases and 1,783 non‐CHD controls. We found that rs11614913 CC was associated with a significantly increased risk of CHD in all three stages combined (P=6.81×10−6). In a genotype–phenotype correlation analysis using 29 cardiac tissue samples of CHD, rs11614913 CC was associated with significantly increased mature miR‐196a expression (P=0.001). In vitro binding assays further revealed that the rs11614913 variant affects HOXB8 binding to mature miR‐196a. This is the first study to indicate that miR‐196a2 rs11614913 plays a role in sporadic CHD susceptibility. Hum Mutat 30:1–6, 2009.

Identification and Characterization of MicroRNAs in Channel Catfish (Ictalurus punctatus) by Using Solexa Sequencing Technology

Channel catfish (Ictalurus spp.) is an economically important species in freshwater aquaculture around the world and occupies a prominent position in the aquaculture industry of the United States. MicroRNAs (miRNAs) play important roles in the regulation of almost every biological process in eukaryotes; however, there is little information available concerning miRNAs in channel catfish. In this study, a small-RNA cDNA library was constructed from 10 tissues of channel catfish, and Solexa sequencing technology was used to perform high-throughput sequencing of the library. A total of 14,919,026 raw reads, representing 161,288 unique sequences, were obtained from the small-cDNA library. After comparing the small RNA sequences with the RFam database, 4,542,396 reads that represent 25,538 unique sequences were mapped to the genome sequence of zebrafish to perform distribution analysis and to screen for candidate miRNA genes. Subsequent bioinformatic analysis identified 237 conserved miRNAs and 45 novel miRNAs in the channel catfish. Stem-loop RT-PCR was applied to validate and profile the expression of the novel miRNAs in 10 tissues. Some novel miRNAs, such as ipu-miR-129b, ipu-miR-7562 and ipu-miR-7553, were expressed in all tissues examined. However, some novel miRNAs appear to be tissue specific. Ipu-miR-7575 is predominantly expressed in stomach. Ipu-miR-7147 and ipu-miR-203c are highly expressed in heart, but are relatively weakly expressed in other tissues. Based on sequence complementarity between miRNAs and mRNA targets, potential target sequences for the 45 novel miRNAs were identified by searching for antisense hits in the reference RNA sequences of the channel catfish. These potential target sequences are involved in immune regulation, transcriptional regulation, metabolism and many other biological functions. The discovery of miRNAs in the channel catfish genome by this study contributes to a better understanding of the role miRNAs play in regulating diverse biological processes in fish and vertebrates.

Genome-Wide Association Study of Prognosis in Advanced Non–Small Cell Lung Cancer Patients Receiving Platinum-Based Chemotherapy

Purpose: Genetic variation may influence chemotherapy response and overall survival in cancer patients. Experimental design: We conducted a genome-wide scan in 535 advanced-stage non–small cell lung cancer (NSCLC) patients from two independent cohorts (307 from Nanjing and 228 from Beijing). A replication was carried out on an independent cohort of 340 patients from Southeastern China followed by a second validation on 409 patients from the Massachusetts General Hospital (Boston, MA). Results: Consistent associations with NSCLC survival were identified for five single-nucleotide polymorphisms (SNP) in Chinese populations with P values ranging from 3.63 × 10−5 to 4.19 × 10−7 in the additive genetic model. The minor allele of three SNPs (rs7629386 at 3p22.1, rs969088 at 5p14.1, and rs3850370 at 14q24.3) were associated with worse NSCLC survival while 2 (rs41997 at 7q31.31 and rs12000445 at 9p21.3) were associated with better NSCLC survival. In addition, rs7629386 at 3p22.1 (CTNNB1) and rs3850370 at 14q24.3 (SNW1-ALKBH1-NRXN3) were further replicated in the Caucasian population. Conclusion: In this three-stage genome-wide association studies, we identified five SNPs as markers for survival of advanced-stage NSCLC patients treated with first-line platinum-based chemotherapy in Chinese Han populations. Two of these SNPs, rs7629386 and rs3850370, could also be markers for survival among Caucasian patients. Clin Cancer Res; 18(19); 5507–14. ©2012 AACR.

Genetic polymorphisms in the precursor MicroRNA flanking region and non-small cell lung cancer survival.

RATIONALE Previously, we reported that common variants in precursor microRNA (pre-miRNA) sequences played a role in the prediction of non-small cell lung cancer (NSCLC) survival. OBJECTIVES To assess whether variants in the pre-miRNA flanking region can influence the clinical behavior of NSCLC. METHODS We conducted a two-stage study to examine the impact of a panel of 85 single-nucleotide polymorphisms on the overall survival of 923 patients with NSCLC (568 in the screening set and 355 in the validation set) in China. MEASUREMENTS AND MAIN RESULTS Eleven single-nucleotide polymorphisms were primarily associated with NSCLC survival in the univariate analysis. However, in the validation set, only miR-30c-1 rs928508 was consistently an NSCLC survival predictor and the protective role of rs928508 AG/GG genotypes was more pronounced among early-stage (stage I/II) patients and patients treated with surgery. The area under the curve at Year 5 was significantly increased from 0.658 to 0.741 after adding the miR-30c-1 rs928508 risk score to the traditional clinical risk score (stage and surgery). Furthermore, in the genotype-phenotype correlation analysis, rs928508 AG/GG genotypes were associated with a significantly decreased expression of precursor and mature miR-30c (P = 0.009 and 0.011), but not with that of its primary miRNA. The expression of the host nuclear transcription factor Y gene was correlated with pri-mir-30c-1, but not with rs928508 genotypes, implicating the coregulation of the transcription of nuclear transcription factor Y and pri-mir-30c-1. CONCLUSIONS Our data indicated, for the first time, that genetic polymorphisms in the pre-miRNA flanking region may be prognostic biomarkers of NSCLC, and rs928508 is such a potential candidate.

Methylation-associated silencing of microRNA-34b in hepatocellular carcinoma cancer.

MicroRNAs (miRNAs) can act as oncogenes or tumor-suppressor genes in human cancers including HCC. Previous studies have identified miR-34 family as an important component of the tumor suppressor network during carcinogenesis. In this study, we investigated the methylation status of miR-34 family in HCC tumor and adjacent non-tumor tissues using methylation-specific PCR (MSP). The methylation frequencies of miR-34a and miR-34b/c were 72.1% (31/43) and 79.1% (34/43) in HCC tissues, which were significantly higher than that in the adjacent non-tumor tissues (P < 0.05), respectively. The results were validated by bisulfite sequencing PCR (BSP). Quantitative reverse transcription polymerase chain reaction (RT-PCR) analysis showed that the expression of miR-34a and miR-34b was significantly down-regulated in HCC tissues compared with adjacent non-tumor tissues (P < 0.05). Moreover, the expression of miR-34b was inversely correlated to CpG island methylation in tumor tissues, but not for miR-34a. In summary, our results suggest that DNA methylation may be involved in the inactivation of miR-34b in HCC.

Evaluation of genetic variants in microRNA biosynthesis genes and risk of breast cancer in Chinese women.

MicroRNAs (miRNA) are a class of small, noncoding RNA molecules involved in a diversity of cellular functions. Single nucleotide polymorphisms (SNPs) in miRNA biosynthesis genes may affect the biogenesis of miRNAs and consequently affect the miRNAs regulation. In this study, we systematically selected 24 functional SNPs located in eight key biosynthesis genes of miRNA (DROSHA, DGCR8, RAN, DICER, AGO2, GEMIN3, GEMIN4 and HIWI) and investigated the association between these SNPs and the risk of breast cancer in a Chinese population. All 24 SNPs were firstly genotyped in stage 1 (878 cases and 900 controls) and three promising SNPs (DROSHA rs2291109, RAN rs7301722 and DGCR8 rs417309) were selected for further validation in stage 2 (914 cases and 967 controls). We found that only one SNP (rs417309) located in the 3′‐UTR of DGCR8 was consistently associated with an increased breast cancer risk in two stages with a combined odds ratio (OR) of 1.50 [95% confidence interval (CI) = 1.16–1.93]. Based on the bioinformatics prediction, rs417309 is located at the binding sites of miR‐106b and miR‐579 in the 3′‐UTR of DGCR8. To evaluate whether rs417309 variant affects the binding capacity of miRNAs, we cotransfected luciferase reporter plasmids of DGCR8 3′‐UTR and miR‐106b/miR‐579 in three cell lines. Luciferase activity assay showed a higher expression level with rs417309 A allele compared with G allele in MCF‐7 cell lines (p = 3.31 × 10–7, 9.29 × 10–7 for miR‐106b and miR‐579, respectively). Our findings suggested that DGCR8 rs417309 G > A might affect breast cancer risk through the interruption of miRNA binding.