H19 serves as a diagnostic biomarker and up-regulation of H19 expression contributes to poor prognosis in patients with gastric cancer.

Emerging evidences indicate that dysregulated long noncoding RNAs (lncRNAs) are implicated in cancer tumorigenesis and progression and might be used as diagnosis and prognosis biomarker, or potential therapeutic targets. LncRNA H19 has been reported to be upregulated in diverse human cancers; however, its clinical significance in gastric cancer (GC) remains elusive. Expression levels of H19 in 128 pairs of GC and adjacent normal tissues, GC cell lines and GC juices compared to their corresponding controls were detected by real-time quantitative polymerase chain reaction (qPCR) assay. A receiver operating characteristic (ROC) curve and Kaplan-Meier analysis were constructed to evaluate the diagnostic and prognostic values. Univariate and multivariate analysis were performed using the Cox proportional hazard analysis. H19 expression was remarkably increased in GC tissues and cell lines compared with that in the normal control, and its up-regulation was significantly correlated to invasion depth (P < 0.001), advanced TNM stage (P = 0.002) and regional lymph nodes metastasis (P < 0.001) in GC. H19 levels were robust in differentiating GC tissues from controls [area under the curve (AUC) = 0.697; 95% confidence interval (CI) = 0.636-0.752, p<0.01]. Kaplan-Meier analysis demonstrated that increased H19 expression contributed to poor overall survival (P = 0.017) and disease-free survival (P = 0.024) of patients. A multivariate survival analysis also indicated that H19 could be an independent prognostic marker. The levels of H19 in gastric juice from gastric patients were significantly higher than those from normal subjects (P = 0.034). Furthermore, knockdown of H19 expression by siRNA could inhibit cell migration and invasion in GC cells partly via regulating E-cadherin protein expression. H19 might serve as a promising biomarker for early detection and prognosis prediction of GC.

LincHOTAIR epigenetically silences miR34a by binding to PRC2 to promote the epithelial-to-mesenchymal transition in human gastric cancer.

lncRNAs play important roles in the epigenetic regulation of carcinogenesis and progression. Previous studies suggest that HOTAIR contributes to gastric cancer (GC) development, and the overexpression of HOTAIR predicts a poor prognosis. In this study, we found that HOTAIR was more highly expressed in diffuse-type GC than in intestinal type (P=0.048). In the diffuse type, there is significant relationship between HOTAIR expression and DFS (P<0.001). CDH1 was downregulated in diffuse-type GC tissues (P=0.0007) and showed a negative relationship with HOTAIR (r(2)=0.154, P=0.0354). In addition, HOTAIR knockdown significantly repressed migration, invasion and metastasis both in vitro and vivo and reversed the epithelial-to-mesenchymal transition in GC cells. We also showed that HOTAIR recruiting and binding to PRC2 epigenetically represses miR34a, which controls the targets C-Met (HGF/C-Met/Snail pathway) and Snail, thus contributing to GC cell-EMT process and accelerating tumor metastasis. Moreover, it is demonstrated that HOTAIR crosstalk with microRNAs during epigenetic regulation. Our results suggest that HOTAIR acts as an EMT regulator and may be a candidate prognostic biomarker and a target for new therapies in GC patients.

SP1-induced upregulation of the long noncoding RNA TINCR regulates cell proliferation and apoptosis by affecting KLF2 mRNA stability in gastric cancer.

The long noncoding RNA TINCR shows aberrant expression in human squamous carcinomas. However, its expression and function in gastric cancer remain unclear. We report that TINCR is strongly upregulated in human gastric carcinoma (GC), where it was found to contribute to oncogenesis and cancer progression. We also revealed that TINCR overexpression is induced by nuclear transcription factor SP1. Silencing TINCR expression inhibited cell proliferation, colony formation, tumorigenicity and apoptosis promotion, whereas TINCR overexpression promoted cell growth, as documented in the SGC7901 and BGC823 cell lines. Mechanistic analyses indicated that TINCR could bind to STAU1 (staufen1) protein, and influence KLF2 mRNA stability and expression, then KLF2 regulated cyclin-dependent kinase genes CDKN1A/P21 and CDKN2B/P15 transcription and expression, thereby affecting the proliferation and apoptosis of GC cells. Together, our findings suggest that TINCR contributes to the oncogenic potential of GC and may constitute a potential therapeutic target in this disease.

Low expression of long noncoding RNA PANDAR predicts a poor prognosis of non-small cell lung cancer and affects cell apoptosis by regulating Bcl-2.

Recently, a novel class of transcripts, long noncoding RNAs (lncRNAs), is involved in diseases including cancer. Here, we investigated the the role of lncRNA PANDAR in the progression of non-small cell lung carcinoma (NSCLC). PANDAR, interacting with NF-YA, was generally downregulated in NSCLC tissues. In a cohort of 140 NSCLC patients, decreased PANDAR expression was negatively correlated with greater tumor size (P<0.001) and advanced TNM stage (P=0.002). Moreover, PANDAR could serve as an independent predictor for overall survival in NSCLC (P=0.015). Further experiments demonstrated that PANDAR expression was induced by p53, and chromatin immunoprecipitation (ChIP) assays confirmed that PANDAR was a direct transcriptional target of p53 in NSCLC cells. PANDAR overexpression significantly repressed the proliferation in vitro and in vivo. We also showed that PANDAR-mediated growth regulation is in part due to the transcriptional modulation of Bcl-2 by interacting with NF-YA, thus affecting NSCLC cell apoptosis. To our knowledge, this is the first report which showed the role of PANDAR in the progression of NSCLC. The p53/PANDAR/NF-YA/Bcl-2 interaction might serve as targets for NSCLC diagnosis and therapy.

EZH2-mediated epigenetic suppression of long noncoding RNA SPRY4-IT1 promotes NSCLC cell proliferation and metastasis by affecting the epithelial-mesenchymal transition.

Recent evidence indicates that long noncoding RNAs (lncRNAs) have a critical role in the regulation of cellular processes such as differentiation, proliferation, and metastasis. These lncRNAs are dysregulated in a variety of cancers and many function as tumor suppressors; however, the regulatory factors involved in silencing lncRNA transcription are poorly understood. In this study, we showed that epigenetic silencing of lncRNA SPRY4 intronic transcript 1 (SPRY4-IT1) occurs in non-small-cell lung cancer (NSCLC) cells through direct transcriptional repression mediated by the Polycomb group protein enhancer of zeste homolog 2 (EZH2). SPRY4-IT1 is derived from an intron within SPRY4, and is upregulated in melanoma cells; knockdown of its expression leads to cell growth arrest, invasion inhibition, and elevated rates of apoptosis. Upon depletion of EZH2 by RNA interference, SPRY4-IT1 expression was restored, and transfection of SPRY4-IT1 into NSCLC cells resulted in a significant antitumoral effect, both in culture and in xenografted nude mice. Moreover, overexpression of SPRY4-IT1 was found to have a key role in the epithelial-mesenchymal transition through the regulation of E-cadherin and vimentin expression. In EZH2-knockdown cells, which characteristically showed impaired cell proliferation and metastasis, the induction of SPRY4-IT1 depletion partially rescued the oncogenic phenotype, suggesting that SPRY4-IT1 repression has an important role in EZH2 oncogenesis. Of most relevance, translation of these findings into human NSCLC tissue samples demonstrated that patients with low levels of SPRY4-IT1 expression had a shorter overall survival time, suggesting that SPRY4-IT1 could be a biomarker for poor prognosis of NSCLC.