• Feng-Zhi Li and Wen-Qiao Zang.
• School of Basic Medical Sciences, Zhengzhou University, Zhengzhou 450001, Henan Province, China.
• World J. Gastroenterol. 2019 Nov 14; 25 (42): 6299-6310.

BackgroundStudies have shown that long non-coding RNAs (lncRNAs) play a key role in almost all key physiological and pathological processes, including different types of malignant tumors. Our previous lncRNA microarray results have shown that lncRNA XLOC_001659 is upregulated in esophageal cancer (EC) tissues, with a fold change of 20.9 relative to normal esophageal tissues. But its effect and the molecular biological mechanisms on proliferation and invasion of EC cells remain unclear.AimTo investigate the effect of lncRNA XLOC_001659 on esophageal squamous cell carcinoma (ESCC) cells and explore the molecular biological mechanisms involved.MethodsRT-qPCR assay was used to quantify the expression levels of lncRNAXLOC-001659 and miR-490-5p. The proliferative capacity of the cells was determined using CCK8 and colony formation assays, and the effect of lncRNAXLOC-001659 on the invasion of ESCC cells was determined by Transwell assay. Dual-luciferase reporter assay was used to detect the target genes of lncRNAXLOC-001659 and miR-490-5p.ResultsThe results of RT-qPCR showed that the expression of lncRNAXLOC_001659 was upregulated in ESCC cells. CCK-8 assay showed that knockdown of lncRNAXLOC_001659 significantly inhibited ESCC cell proliferation. Colony formation and Transwell invasion assays showed that knockdown of lncRNAXLOC_001659 or overexpression of miR-490-5p significantly inhibited ESCC cell growth and invasion. Furthermore, lncRNAXLOC_001659 acts as an endogenous sponge by competitively binding to miR-490-5p to downregulate miR-490-5p. Further results confirmed that miR-490-5p targeted PIK3CA, and the recovery of PIK3CA rescued lncRNAXLOC_001659 knockdown or miR-490-5p overexpression-mediated inhibition of cell proliferation and invasion, which suggested the presence of an lncRNAXLOC_001659/miR-490-5p/PIK3CA regulatory axis.ConclusionKnockdown of lncRNA XLOC_001659 inhibits proliferation and invasion of ESCC cells via regulation of miR-490-5p/PIK3CA, suggesting that it may play a role in ESCC tumorigenesis and progression.©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.

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