Lin Xu

Serum MicroRNA Signatures Identified in a Genome-Wide Serum MicroRNA Expression Profiling Predict Survival of Non–Small-Cell Lung Cancer

PURPOSE Recent findings that human serum contains stably expressed microRNA (miRNA) have revealed a great potential of serum miRNA signature as disease fingerprints to predict survival. We used genome-wide serum miRNA expression analysis to investigate the role of serum miRNA in predicting prognosis of non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS To control disease heterogeneity, we used patients with stages I to IIIa lung adenocarcinoma and squamous cell carcinoma, who were treated with both operation and adjuvant chemotherapies. In the discovery stage, Solexa sequencing followed by individual quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) assays was used to test the difference in levels of serum miRNAs between 30 patients with longer survival (alive and mean survival time, 49.54 months) and 30 patients with shorter survival matched by age, sex, and stage (dead and mean survival time, 9.54 months). The detected serum miRNAs then were validated in 243 patients (randomly classified into two subgroups: n = 120 for the training set, and n = 123 for the testing set). RESULTS Eleven serum miRNAs were found to be altered more than five-fold by Solexa sequencing between longer-survival and shorter-survival groups, and levels of four miRNAs (ie, miR-486, miR-30d, miR-1 and miR-499) were significantly associated with overall survival. The four-miRNA signature also was consistently an independent predictor of overall survival for both training and testing samples. CONCLUSION The four-miRNA signature from the serum may serve as a noninvasive predictor for the overall survival of NSCLC.

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.

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.

Long noncoding RNA: an emerging paradigm of cancer research

Recent studies have demonstrated the importance of non-protein coding part of human genome in carcinogenesis and metastasis. Among numerous kinds of non-protein coding RNAs, long noncoding RNAs (lncRNAs) play a key regulatory role in cancer biology. LncRNAs are dysregulated in different kinds of cancer and the expression levels of certain lncRNAs are associated with recurrence, metastasis, and prognosis of cancer. It is also proved that overexpression of certain lncRNAs, behaving like oncogenes, can promote matrix invasion of cancer cells and tumor growth. In this review, we focus our attention on lncRNAs those have been validated in human cancer tissues to suggest reasonable strategies for future research. We introduce an update view of lncRNA, extract cancer-related lncRNAs from literature, and describe the known functions and possible underlying molecular mechanisms of some well investigated lncRNAs (MALAT1, HOX antisense intergenic RNA, and highly upregulated in hepatocellular cancer), as well as their current and potential future application in cancer diagnosis (PCA3) and treatment (H19).

Identification of ten serum microRNAs from a genome-wide serum microRNA expression profile as novel noninvasive biomarkers for nonsmall cell lung cancer diagnosis.

The detection of nonsmall cell lung cancer (NSCLC) at an early stage presents a daunting challenge due to the lack of a specific noninvasive marker. The discovery of microRNAs (miRNAs), particularly those found in serum, has opened a new avenue for tumor diagnosis. To determine whether the expression profile of serum miRNAs can serve as a NSCLC fingerprint, we performed Taqman probe‐based quantitative RT‐PCR assay to selected differentially expressed serum miRNAs from a sample set including 400 NSCLC cases and 220 controls, and risk score analysis to evaluate the diagnostic value of the serum miRNA profiling system. After a two‐phase selection and validation process, 10 miRNAs were found to have significantly different expression levels in NSCLC serum samples compared with the control serum samples. Risk score analysis showed that this panel of miRNAs was able to distinguish NSCLC cases from controls with high sensitivity and specificity. Under ROC curves, the AUC for tumor identification in training set and validation set were 0.966 and 0.972, respectively. Furthermore, the expression profile of the 10‐serum miRNAs was correlated with the stage of NSCLC patients, especially in younger patients and patients with current smoking habits. More importantly, the serum miRNA‐based biomarker for early NSCLC detection was supported by a retrospective analysis in which the 10‐serum miRNA profile could accurately classify serum samples collected up to 33 months ahead of the clinical NSCLC diagnosis. Taken together, we demonstrate that the profiling of 10‐serum miRNAs provides a novel noninvasive biomarker for NSCLC diagnosis.

LncRNA HOXA11-AS promotes proliferation and invasion of gastric cancer by scaffolding the chromatin modification factors PRC2, LSD1 and DNMT1

Long noncoding RNAs (lncRNA) have been implicated in human cancer but their mechanisms of action are mainly undocumented. In this study, we investigated lncRNA alterations that contribute to gastric cancer through an analysis of The Cancer Genome Atlas RNA sequencing data and other publicly available microarray data. Here we report the gastric cancer-associated lncRNA HOXA11-AS as a key regulator of gastric cancer development and progression. Patients with high HOXA11-AS expression had a shorter survival and poorer prognosis. In vitro and in vivo assays of HOXA11-AS alterations revealed a complex integrated phenotype affecting cell growth, migration, invasion, and apoptosis. Strikingly, high-throughput sequencing analysis after HOXA11-AS silencing highlighted alterations in cell proliferation and cell-cell adhesion pathways. Mechanistically, EZH2 along with the histone demethylase LSD1 or DNMT1 were recruited by HOXA11-AS, which functioned as a scaffold. HOXA11-AS also functioned as a molecular sponge for miR-1297, antagonizing its ability to repress EZH2 protein translation. In addition, we found that E2F1 was involved in HOXA11-AS activation in gastric cancer cells. Taken together, our findings support a model in which the EZH2/HOXA11-AS/LSD1 complex and HOXA11-AS/miR-1297/EZH2 cross-talk serve as critical effectors in gastric cancer tumorigenesis and progression, suggesting new therapeutic directions in gastric cancer. Cancer Res; 76(21); 6299-310. ©2016 AACR.

Association analyses identify multiple new lung cancer susceptibility loci and their interactions with smoking in the Chinese population

To find additional susceptibility loci for lung cancer, we tested promising associations from our previous genome-wide association study (GWAS) of lung cancer in the Chinese population in an extended validation sample size of 7,436 individuals with lung cancer (cases) and 7,483 controls. We found genome-wide significant (P < 5.0 × 10−8) evidence for three additional lung cancer susceptibility loci at 10p14 (rs1663689, close to GATA3, P = 2.84 × 10−10), 5q32 (rs2895680 in PPP2R2B-STK32A-DPYSL3, P = 6.60 × 10−9) and 20q13.2 (rs4809957 in CYP24A1, P = 1.20 × 10−8). We also found consistent associations for rs247008 at 5q31.1 (IL3-CSF2-P4HA2, P = 7.68 × 10−8) and rs9439519 at 1p36.32 (AJAP1-NPHP4, P = 3.65 × 10−6). Four of these loci showed evidence for interactions with smoking dose (P = 1.72 × 10−10, P = 5.07 × 10−3, P = 6.77 × 10−3 and P = 4.49 × 10−2 for rs2895680, rs4809957, rs247008 and rs9439519, respectively). These results advance our understanding of lung cancer susceptibility and highlight potential pathways that integrate genetic variants and smoking in the development of lung cancer.

Functional polymorphisms of matrix metalloproteinase-9 are associated with risk of occurrence and metastasis of lung cancer.

Purpose: Matrix metalloproteinase 9 (MMP-9) plays critical roles in cancer development and aggression. Nonsynonymous single-nucleotide polymorphisms (SNP) in the functional domain of the MMP-9 gene may influence substrate and inhibitor binding and contribute to cancer predisposition and aggression. Patients and Methods: To test our hypothesis that common nonsynonymous SNPs, R279Q, P574R, and R668Q, in MMP-9 are associated with lung cancer development and metastasis, we conducted a case-control study of 744 patients with incident lung cancer and 747 cancer-free controls in Southeast China. Multivariate logistic regression analysis was used to calculate adjusted odds ratio (OR) and 95% confidence interval (95% CI). Results: We found that compared with the 279QQ genotype, the 279RR genotype was associated with significant elevated risk of lung cancer with metastasis (adjusted OR, 1.79; 95% CI, 1.03-3.08), whereas the 574PR heterozygote and 574PP homozygote had 1.46-fold (95% CI, 0.94-2.26) and 1.69-fold elevated risk (95% CI, 1.10-2.60), respectively, compared with the 574RR genotype. When we examined the combined effect of R279Q and P574R and used the 279R and 574P as the risk alleles, a significantly increased risk of lung cancer was associated with both the genotypes containing “1 to 2 risk alleles” (adjusted OR, 2.16; 95% CI, 1.30-3.59) and containing “>2 risk alleles” (adjusted OR, 2.44; 95% CI, 1.48-4.03), and it was more pronounced in 290 lung cancer cases with metastasis [adjusted OR, 2.30 (95% CI, 1.09-4.85) for the 1 to 2 risk alleles subgroup and adjusted OR, 2.82 (95% CI, 1.35-5.88) for the >2 risk alleles subgroup], compared with those without any risk alleles. However, no overall significant associations were observed between R668Q and lung cancer risk in this study population. Conclusion: These findings indicate that the potentially functional polymorphisms, MMP-9 P574R and R279Q, may confer the biomarker in the occurrence and metastasis of primary lung cancer. Further functional studies including these two genetic variants are warranted to confirm our findings.

Upregulation of the long noncoding RNA TUG1 promotes proliferation and migration of esophageal squamous cell carcinoma.

Esophageal squamous cell carcinoma (ESCC) is one of the prevalent and deadly cancers worldwide, especially in Eastern Asia. The prognosis of ESCC remains poor; thus, it is still necessary to further dissect the underlying mechanisms and explore therapeutic targets of ESCC. Recent studies show that long noncoding RNAs (lncRNAs) have critical roles in diverse biological processes, including tumorigenesis. Some lncRNAs, such as HOTAIR and POU3F3, were reported to play important roles in ESCC. Here, we characterized the expression profile of taurine-upregulated gene 1 (TUG1), a lncRNA recruiting and binding to polycomb repressive complex 2 (PRC2), in ESCC. In a cohort of 62 patients, TUG1 was significantly overexpressed in ESCC tissues compared with paired adjacent normal tissues, and high expression level of TUG1 was associated with family history and upper segment of esophageal cancer (p < 0.05). Further, in vitro silencing TUG1 via siRNA inhibited the proliferation and migration of ESCC cells and blocked the progression of cell cycle. Therefore, our study indicates that TUG1 promotes proliferation and migration of ESCC cells and is a potential oncogene of ESCC.

Common genetic variants on 5p15.33 contribute to risk of lung adenocarcinoma in a Chinese population.

Chromosome 5p15.33, containing TERT and CLPTM1L genes, was recently identified as one of the susceptible regions for lung cancer in Caucasian populations. We hypothesized that single-nucleotide polymorphisms (SNPs) identified in this region in Caucasians are also important in the development of lung cancer in Chinese population. To test this hypothesis, we genotyped two most significant SNPs reported in Caucasians, rs2736100A/C and rs402710C/T at 5p15.33, in a case-control study with 1221 non-small cell lung cancer (NSCLC) cases and 1344 cancer-free controls in a Chinese population. We found that rs2736100C allele in TERT gene was associated with a significantly increased risk of NSCLC with adjusted odds ratios of 1.26 [95% confidence interval (CI) = 1.05-1.51] and 1.31 (95% CI = 1.04-1.66) for one or two copies of the variant C allele, respectively. This significant association was more prominent among female (P for heterogeneity: 0.044), non-smokers (P for heterogeneity: 0.054) and/or the subjects with adenocarcinoma (P for heterogeneity: 0.058). However, no significant association was found between rs402710C/T and NSCLC risk. These results suggest that genetic variants in 5p15.33, especially in TERT gene, may also predispose the susceptibility of lung cancer, especially adenocarcinoma, in Chinese population.