Long noncoding RNAs are involved in diseases including cancer. Here, we reported that ANRIL (CDKN2B-AS1), a 3.8-kb long noncoding RNA, recruiting and binding to PRC2, was generally upregulated in human gastric cancer (GC) tissues. In a cohort of 120 GC patients, the higher expression of ANRIL was significantly correlated with a higher TNM stage (P=0.041) and tumor size (P=0.001). Multivariate analyses revealed that ANRIL expression served as an independent predictor for overall survival (P=0.036). Further experiments revealed that ANRIL knockdown significantly repressed the proliferation both in vitro and in vivo. We also showed that E2F1 could induce ANRIL and ANRIL-mediated growth promotion is in part due to epigenetic repression of miR-99a/miR-449a in Trans (controlling the targets—mTOR and CDK6/E2F1 pathway) by binding to PRC2, thus forming a positive feedback loop, continuing to promote GC cell proliferation. To our knowledge, this is the first report showed that the role of ANRIL in the progression of GC and ANRIL could crosstalk with microRNAs in epigenetic level. Our results suggest that ANRIL, as a growth regulator, may serve as a candidate prognostic biomarker and target for new therapies in human gastric cancer.
BackgroundRecent evidence indicates that long noncoding RNAs (lncRNAs) play a critical role in the regulation of cellular processes, such as differentiation, proliferation and metastasis. These lncRNAs are found to be dysregulated in a variety of cancers. BRAF activated non-coding RNA (BANCR) is a 693-bp transcript on chromosome 9 with a potential functional role in melanoma cell migration. The clinical significance of BANCR, and its’ molecular mechanisms controlling cancer cell migration and metastasis are unclear.MethodsExpression of BANCR was analyzed in 113 non-small cell lung cancer (NSCLC) tissues and seven NSCLC cell lines using quantitative polymerase chain reaction (qPCR) assays. Gain and loss of function approaches were used to investigate the biological role of BANCR in NSCLC cells. The effects of BANCR on cell viability were evaluated by MTT and colony formation assays. Apoptosis was evaluated by Hoechst staining and flow cytometry. Nude mice were used to examine the effects of BANCR on tumor cell metastasis in vivo. Protein levels of BANCR targets were determined by western blotting and fluorescent immunohistochemistry.ResultsBANCR expression was significantly decreased in 113 NSCLC tumor tissues compared with normal tissues. Additionally, reduced BANCR expression was associated with larger tumor size, advanced pathological stage, metastasis distance, and shorter overall survival of NSCLC patients. Reduced BANCR expression was found to be an independent prognostic factor for NSCLC. Histone deacetylation was involved in the downregulation of BANCR in NSCLC cells. Ectopic expression of BANCR impaired cell viability and invasion, leading to the inhibition of metastasis in vitro and in vivo. However, knockdown of BANCR expression promoted cell migration and invasion in vitro. Overexpression of BANCR was found to play a key role in epithelial-mesenchymal transition (EMT) through the regulation of E-cadherin, N-cadherin and Vimentin expression.ConclusionWe determined that BANCR actively functions as a regulator of EMT during NSCLC metastasis, suggesting that BANCR could be a biomarker for poor prognosis of NSCLC.
BackgroundRecently, miR-451 as a tumor suppressor has been reported in other studies. However, whether miR-451 can affect the sensitivity of non-small cell lung cancer (NSCLC) cells to cisplatin (DDP) remains unclear. The aim of this study is to evaluate the roles of miR-451 in the sensitivity of NSCLC cells to DDP.MethodsQuantitative RT-PCR assay was performed to detect the expression of miR-451 in 10 pairs of NSCLC and noncancerous tissue samples. pcDNA-GW/EmGFP-miR-451 was stably transfected into NSCLC cell line (A549). Then, the effects of miR-451 upregulation on growth, colony formation and apoptosis of A549 cells were investigated. Finally, the effects of miR-451 upregulation on in vitro and in vivo sensitivity of A549 cells of DDP were also determined.ResultsThe level of miR-451 expression in NSCLC tissues was significantly higher than that in corresponding noncancerous tissues. Ectopic overexpression of miR-451 could significantly inhibit growth and induce apoptosis of A549 cells. Moreover, ectopic overexpression of miR-451 could sensitize A549 cells to DDP possibly by increasing DDP-induced apoptosis which might be associated with the inactivation of Akt signaling pathway.ConclusionsThis study demonstrated for the first time that combination of DDP application with miR-451 upregulation might be a potential strategy for the treatment of human NSCLC.
BackgroundMicroRNAs (miRNAs) are short, non-coding RNAs (~22 nt) that play important roles in the pathogenesis of human diseases by negatively regulating gene expression. Although miR-196a has been implicated in several other cancers, its role in non-small cell lung cancer (NSCLC) is unknown. The aim of the present study was to examine the expression pattern of miR-196a in NSCLC and its clinical significance, as well as its biological role in tumor progression.MethodsExpression of miR-196a was analyzed in 34 NSCLC tissues and five NSCLC cell lines by quantitative reverse-transcription polymerase chain reaction (qRT-PCR). The effect of DNA methylation on miR-196a expression was investigated by 5-aza-2-deoxy-cytidine treatment and bisulfite sequencing. The effect of miR-196a on proliferation was evaluated by MTT and colony formation assays, and cell migration and invasion were evaluated by transwell assays. Analysis of target protein expression was determined by western blotting. Luciferase reporter plasmids were constructed to confirm the action of miR-196a on downstream target genes, including HOXA5. Differences between the results were tested for significance using Student’s t-test (two-tailed).ResultsmiR-196a was highly expressed both in NSCLC samples and cell lines compared with their corresponding normal counterparts, and the expression of miR-196a may be affected by DNA demethylation. Higher expression of miR-196a in NSCLC tissues was associated with a higher clinical stage, and also correlated with NSCLC lymph-node metastasis. In vitro functional assays demonstrated that modulation of miR-196a expression affected NSCLC cell proliferation, migration and invasion. Our analysis showed that miR-196a suppressed the expression of HOXA5 both at the mRNA and protein levels, and luciferase assays confirmed that miR-196a directly bound to the 3’untranslated region of HOXA5. Knockdown of HOXA5 expression in A549 cells using RNAi was shown to promote NSCLC cell proliferation, migration and invasion. Finally, we observed an inverse correlation between HOXA5 and miR-196a expression in NSCLC tissues.ConclusionsOur findings indicate that miR-196a is significantly up-regulated in NSCLC tissues, and regulates NSCLC cell proliferation, migration and invasion, partially via the down-regulation of HOXA5. Thus, miR-196a may represent a potential therapeutic target for NSCLC intervention.
BackgroundMounting evidence indicates that long noncoding RNAs (lncRNAs) could play a pivotal role in cancer biology. However, the role and molecular mechanism and global genes that were mediated by lncRNA AFAP1-AS1 in non–small cell lung cancer (NSCLC) remain largely unknown.MethodsExpression of AFAP1-AS1 was analyzed in 92 NSCLC tissues and cell lines by Quantitative real time polymerase chain reaction (qRT-PCR). The effect of AFAP1-AS1 on proliferation was evaluated by function assays both in in vitro and in vivo. RNA-seq assays were performed after knockdown AFAP1-AS1. RNA immunoprecipitation (RIP) was performed to confirm the interaction between AFAP1-AS1 and EZH2. Chromatin immunoprecipitation (ChIP) was used to study the promoter region of p21.ResultsAFAP1-AS1 expression was increased in NSCLC tissues and was correlated with clinical outcomes of NSCLC. Further experiments revealed that inhibition of its expression in NSCLC cells resulted in diminished cell growth in vitro and in vivo. RNA-seq revealed that knockdown of AFAP1-AS1 could induce the expression of p21. Mechanistic investigations found that AFAP1-AS1 could interact with EZH2 and recruit EZH2 to the promoter regions of p21, thus epigenetically repressing p21 expression.ConclusionsTogether, these results suggest that lncRNA AFAP1-AS1 may serve as a candidate prognostic biomarker and target for new therapies in human NSCLC.Electronic supplementary materialThe online version of this article (10.1186/s12943-018-0836-7) contains supplementary material, which is available to authorized users.
Cardiac Na + -Ca 2+ exchange (NCX1) inactivates in excised membrane patches when cytoplasmic Ca 2+ is removed or cytoplasmic Na + is increased. Exogenous phosphatidylinositol-4,5-bisphosphate (PIP 2 ) can ablate both inactivation mechanisms, while it has no effect on inward exchange current in the absence of cytoplasmic Na + . To probe PIP 2 effects in intact cells, we manipulated PIP 2 metabolism by several means. First, we used cell lines with M1 (muscarinic) receptors that couple to phospholipase C's (PLCs). As expected, outward NCX1 current (i.e. Ca 2+ influx) can be strongly inhibited when M1 agonists induce PIP 2 depletion. However, inward currents (i.e. Ca 2+ extrusion) without cytoplasmic Na + can be increased markedly in parallel with an increase of cell capacitance (i.e. membrane area). Similar effects are incurred by cytoplasmic perfusion of GTPγS or the actin cytoskeleton disruptor latrunculin, even in the presence of non-hydrolysable ATP (AMP-PNP). Thus, G-protein signalling may increase NCX1 currents by destabilizing membrane cytoskeleton-PIP 2 interactions. Second, to increase PIP 2 we directly perfused PIP 2 into cells. Outward NCX1 currents increase as expected. But over minutes currents decline substantially, and cell capacitance usually decreases in parallel. Third, using BHK cells with stable NCX1 expression, we increased PIP 2 by transient expression of a phosphatidylinositol-4-phosphate-5-kinase (hPIP5KIβ) and a PI4-kinase (PI4KIIα). NCX1 current densities were decreased by > 80 and 40%, respectively. Fourth, we generated transgenic mice with 10-fold cardiac-specific overexpression of PI4KIIα. This wortmannin-insensitive PI4KIIα was chosen because basal cardiac phosphoinositides are nearly insensitive to wortmannin, and surface membrane PI4-kinase activity, defined functionally in excised patches, is not blocked by wortmannin. Both phosphatidylinositol-4-phosphate (PIP) and PIP 2 were increased significantly, while NCX1 current densities were decreased by 78% with no loss of NCX1 expression. Most mice developed cardiac hypertrophy, and immunohistochemical analysis suggests that NCX1 is redistributed away from the outer sarcolemma. Cholera toxin uptake was increased 3-fold, suggesting that clathrin-independent endocytosis is enhanced. We conclude that direct effects of PIP 2 to activate NCX1 can be strongly modulated by opposing mechanisms in intact cells that probably involve membrane cytoskeleton remodelling and membrane trafficking.
A new β-stereoselective D- and L-arabinofuranosylation method has been developed employing 5-O-(2-quinolinecarbonyl) substituted arabinosyl ethyl thioglycosides as glycosyl donors. The approach allows a wide range of acceptor substrates to be used; the β-selectivity is good-to-excellent. Stereoselective synthesis of a mannose-capped octasaccharide portion from a mycobacterial cell wall polysaccharide was then carried out to demonstrate the utility of this methodology.
BackgroundExpression of the long non-coding RNA (lncRNA) LOC285194 was previously shown to be correlated with aggressive clinicopathological features and poor prognosis in several cancers. The aim of the present study was to explore the relationship between LOC285194 expression and clinical outcomes in esophageal squamous cell carcinoma (ESCC), so as to assess whether it could be a novel biomarker for prognosis and prediction of response to therapy on ESCC patients.MethodsThe method of quantitative real-time polymerase chain reaction (qRT-PCR) was used to measure LOC285194 expression in pretreatment biopsy specimens and matched normal tissue derived from ESCC patients who underwent preoperative chemoradiotherapy followed by surgical resection (CRT + S group; n = 55) or from those who received surgical resection alone (S group; n = 87). The association between LOC285194 expression and clinicopathological features and prognosis were then analyzed.ResultsLOC285194 expression was significantly down-regulated in ESCC tumor tissues when compared with the adjacent normal tissues (p < 0.001). Low expression of LOC285194 was associated with larger tumor size (p = 0.002), advanced TNM stage (p = 0.018), more lymph node metastases (p = 0.013) and distant metastases (p = 0.015). In the CRT + S group, the pathological complete response rate was 57% (16/28) for the LOC285194-high group, and 15% (4/27) for the LOC285194-low group. Univariate analysis revealed that low expression of LOC285194 was significantly correlated with CRT response (p = 0.002). Moreover, Kaplan-Meier survival analysis revealed that patients with low expression of LOC285194 had a decreased disease free survival (DFS) (p < 0.001) and overall survival (OS) (p < 0.001). Multivariable analysis further identified low expression of LOC285194 as an independent prognosis factor for CRT response (p = 0.011), DFS (p < 0.001) and OS (p = 0.002).ConclusionDecreased expression of LOC285194 could serve as a molecular marker to predict the clinical outcome of ESCC patients after surgery, and select patients who would benefit from preoperative CRT.
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