Recently, long non-coding RNAs (lncRNAs) are identified as new crucial regulators of diverse cellular processes, including cell proliferation, differentiation and cancer cells metastasis. Accumulating evidence has revealed that aberrant lncRNA expression plays important roles in carcinogenesis and tumor progression. However, the expression pattern and biological function of lncRNAs in non-small-cell lung cancer (NSCLC) remain largely unknown. In this study, we performed comprehensive analysis of lncRNA expression in human NSCLC samples by using microarray data from Gene Expression Omnibus. After validation in a cohort of 80 pairs of NSCLC tissues, we identified a differentially expressed novel oncogenic lncRNA termed as AGAP2-AS1. The AGAP2-AS1 expression level was significantly upregulated in NSCLC tissues and negatively correlated with poor prognostic outcomes in patients. In vitro loss- and gain-of-function assays revealed that AGAP2-AS1 knockdown inhibited cell proliferation, migration and invasion, and induced cell apoptosis. In vivo assays also confirmed the ability of AGAP2-AS1 to promote tumor growth. Furthermore, mechanistic investigation showed that AGAP2-AS1 could bind with enhancer of zeste homolog 2 and lysine (K)-specific demethylase 1A, and recruit them to KLF2 and LATS2 promoter regions to repress their transcription. Taken together, our findings indicate that AGAP2-AS1 may act as an oncogene by repressing tumor-suppressor LATS2 and KLF2 transcription. By clarifying the AGAP2-AS1 mechanisms underlying NSCLC development and progression, these findings might promote the development of novel therapeutic strategies for this disease.
BackgroundNowadays, despite great progress in cancer research, the detailed mechanisms of colorectal cancer (CRC) are still poorly understood. Circular RNAs (circRNAs), a new star of the non-coding RNA network, have been identified as critical regulators in various cancers, including CRC.Methods and resultsIn this study, by using unsupervised hierarchical clustering analysis, a novel dysregulated circRNA, hsa_circ_0000069, was found. The expression of hsa_circ_0000069 was measured in 30 paired CRC tissues and adjacent noncancerous tissues using quantitative polymerase chain reaction. A high expression of hsa_circ_0000069 was observed in CRC tissues and correlated with patients’ age and tumor, node, metastasis (TNM) stage (P<0.05). Furthermore, by using specifically designed siRNAs in CRC cells, a functional analysis was performed which revealed that hsa_circ_0000069 knockdown could notably inhibit cell proliferation, migration, and invasion, and induce G0/G1 phase arrest of cell cycle in vitro.ConclusionThis study’s findings are the first to demonstrate that hsa_circ_0000069, an important regulator in cancer progression, could be a promising target in the diagnosis and therapy in colorectal cancer.
BackgroundLong non-coding RNAs (lncRNAs) are not translated into proteins and were initially considered to be part of the ‘dark matter’ of the genome. Recently, it has been shown that lncRNAs play a role in the recruitment of chromatin modifying complexes and can influence gene expression. However, it is unknown if lncRNAs function in a similar way in cancer.ResultsHere, we show that the lncRNA ROR occupies and activates the TESC promoter by repelling the histone G9A methyltransferase and promoting the release of histone H3K9 methylation. Suppression of ROR in tumors results in silencing of TESC expression, and G9A-mediated histone H3K9 methylation in the TESC promoter is restored, which significantly reduces tumor growth and metastasis. Without ROR silencing, TESC knockdown presents consistent and significant reductions in tumor progression.ConclusionsOur results reveal a novel mechanism by which ROR may serve as a decoy oncoRNA that blocks binding surfaces, preventing the recruitment of histone modifying enzymes, thereby specifying a new pattern of histone modifications that promote tumorigenesis.Electronic supplementary materialThe online version of this article (doi:10.1186/s13059-015-0705-2) contains supplementary material, which is available to authorized users.
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