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

Background/Aims: Vasculogenic mimicry (VM) has been reported to be a novel glioma neovascularization process. Anti-VM therapy provides new insight into glioma clinical management. In this study, we revealed the role of the long non-coding RNA HOXA cluster antisense RNA 2 (HOXA-AS2) in malignant glioma behaviors and VM formation. Methods: Quantitative real-time PCR was performed to determine the expression levels of HOXA-AS2 in glioma samples and glioblastoma cell lines. CD34-periodic acid-Schiff dual-staining was performed to assess VM in glioma samples. CCK-8, transwell, and Matrigel tube formation assays were performed to measure the effects of HOXA-AS2 knockdown on cell viability, migration, invasion, and VM tube formation, respectively. RNA immunoprecipitation, dual-luciferase reporter and Western blot assays were performed to explore the molecular mechanisms underlying the functions of HOXS-AS2 in glioblastoma cells. A nude mouse xenograft model was used to investigate the role of HOXA-AS2 in xenograft glioma growth and VM density. Student’s t-tests, one-way ANOVAs followed by Bonferroni posthoc tests, and chi-square tests were used for the statistical analyses. Results: HOXA-AS2 was upregulated in glioma samples and cell lines and was positively correlated with VM. HOXA-AS2 knockdown attenuated cell viability, migration, invasion, and VM formation in glioma cells and inhibited the expression of vascular endothelial-cadherin (VE-cadherin), as well as the expression and activity of matrix metalloproteinase matrix metalloproteinase (MMP)-2 and MMP-9. miR-373 was downregulated in glioma samples and cell lines and suppressed malignancy in glioblastoma cells. HOXA-AS2 bound to miR-373 and negatively regulated its expression. Epidermal growth factor receptor (EGFR), a target of miR-373, increased the expression levels of VE-cadherin, as well as the expression and activity levels of MMP-2 and MMP-9, via activating phosphatidylinositol 3-kinase/serine/threonine kinase pathways. HOXA-AS2 knockdown combined with miR-373 overexpression yielded optimal tumor suppressive effects and the lowest VM density in vivo. Conclusion: HOXA-AS2 knockdown inhibited malignant glioma behaviors and VM formation via the miR-373/EGFR axis.

Section: Discussionmentioning

confidence: 50%

Long Non-Coding RNA HOXA-AS2 Regulates Malignant Glioma Behaviors and Vasculogenic Mimicry Formation via the MiR-373/EGFR Axis

Gao

Liu

et al. 2017

“…Moreover, Wu et al demonstrated that HOTAIR contributes to the direct suppression of E-cadherin by recruiting enhancer of zeste homolog 2 (EZH2) to the E-cadherin promoter [42]. Supporting evidence were found that HOTAIR expression levels were negatively correlated with those of E-cadherin in gastric cancer and oral squamous cell carcinoma tissues [41,42]. Besides, Hong et al demonstrated that HOTAIR also functions as a ceRNA for miR-217, thus regulating HIF-1α/AXL signaling and promoting EMT process in renal cell carcinoma [43].…”

Section: Introductionmentioning

confidence: 58%

“…Further study revealed that HOTAIR-PRC2 complex epigenetically silences a tumor-suppressive microRNA miR-34a, which controls the downstream targets c-Met (HGF/c-Met/Snail pathway) and Snail, thus contributing to the process of EMT and tumor metastasis in gastric cancer (Fig. 2b, i) [41]. Moreover, Wu et al demonstrated that HOTAIR contributes to the direct suppression of E-cadherin by recruiting enhancer of zeste homolog 2 (EZH2) to the E-cadherin promoter [42].…”

Section: Introductionmentioning

confidence: 99%

Missing Links in Epithelial-Mesenchymal Transition: Long Non-Coding RNAs Enter the Arena

Wang

Yang

Jia

et al. 2017

Cancer metastasis occurs through a series of sequential steps, which involves dissemination of tumor cells from a primary site and colonization in distant tissues. To promote the invasion-metastasis cascade, carcinoma cells usually initiate a cell-biological program called epithelial-mesenchymal transition (EMT), which is orchestrated by a set of master regulators, including TGF-β, Snail, ZEB and Twist families. The biological activities of these molecules are tightly regulated by a variety of cell-intrinsic pathways as well as extracellular cues. Recently, accumulating evidence indicates that long non-coding RNAs (lncRNAs) represent some of the most differentially expressed transcripts between primary and metastatic cancers. LncRNAs including MALAT1, HOTAIR, H19, LncRNA-ATB, and LincRNA-ROR have been reported to be involved in the process of EMT, mainly through cross-talking with master regulators of EMT. Thus, understanding the different and precise molecular mechanisms by which functional lncRNAs switch EMT on and off is important for opening up new avenues in lncRNA-directed diagnosis, prognosis, and therapeutic intervention against cancer.

“…Recent studies have suggested that lncRNAs are required for epigenetic regulation of target genes through binding with PRC2, thus contributing to cancer progression [30, 35, 36]. EZH2 and SUZ12, as two core components of PRC2 complex, have been shown to be involved in cancer progression [37-39].…”

Section: Resultsmentioning

confidence: 99%

Long Non-Coding RNA SH3PXD2A-AS1 Promotes Cell Progression Partly Through Epigenetic Silencing P57 and KLF2 in Colorectal Cancer

Peng

Zhou

et al. 2018

Background/Aims: Colorectal cancer (CRC) is one of the most commonly diagnosed malignancies worldwide. Current evidence has revealed the key roles of long non-coding RNAs (IncRNAs) in multiple cancers, including CRC. In this study we identified the lncRNA SH3PXD2A-AS1 as a novel molecule associated with CRC progression by analyzing the publicly available data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets. Methods: Quantitative real-time polymerase chain reaction (qRT-PCR) assays were performed to examine the expression levels of SH3PXD2A-AS1 in CRC tissue samples and CRC cell lines. Cell viability examination, colony-formation experiments, ethynyl deoxyuridine (Edu) assays and flow cytometry were performed to investigate the roles of SH3PXD2A-AS1 in CRC proliferation, cell cycle regulation, and apoptosis. Transwell assays were used to explore the effects of SH3PXD2A-AS1 on CRC cells migration and invasion. A nude mice model was used to assess the effects of SH3PXD2A-AS1 on tumorigenesis in vivo. Subcellular fractionation, RNA immunoprecipitation (RIP), and chromatin immunoprecipitation (ChIP) assays were conducted to detect the molecular mechanisms of SH3PXD2A-ASl-mediated gene expression. Rescue assays were used to determine whether P57 and Kruppel-like factor 2 (KLF2) were involved in SH3PXD2A-ASl-dependent CRC proliferation. Results: We firstly found that SH3PXD2A-AS1 was significantly upregulated in CRC tissues and cell lines, and overexpression of SH3PXD2A-AS1 was correlated with tumor size, TNM stage, and lymph node metastasis in patients with CRC. Furthermore, SH3PXD2A-AS1 knockdown inhibited CRC cells proliferation, migration and invasion in vitro, and suppressed tumorigenesis in vivo. Mechanistic studies indicated that SH3PXD2A-AS1 could epiqenetically repress P57 and KLF2 expression through interaction with EZH2. Rescue experiments suggested that SH3PXD2A-ASl-mediated oncogenesis was impaired by overexpression of P57 or KLF2. Interestingly, the expression of SH3PXD2A-AS1 was inversely correlated with the expression of P57 and KLF2 in CRC tissue samples. Conclusion: Our research presents the first evidence that SH3PXD2A-AS1 acts as an oncogene in CRC, and may be a promising diagnostic or therapeutic target in patients with CRC.