Long Non-coding RNA LINC00320 Inhibits Tumorigenicity of Glioma Cells and Angiogenesis Through Downregulation of NFKB1-Mediated AQP9.

Lisha Chang,Xin Xiong,Jiang Zhang,Fuling Zhou,Jian Liu,Yunhe Zhang,Dali Wang,Zhe Bian

doi:10.3389/fncel.2020.542552

Lisha Chang, Xin Xiong + Show 6 more

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https://doi.org/10.3389/fncel.2020.542552

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Abstract

The inhibitory effect of long intergenic non-coding RNA 00320 (LINC00320) in glioma cell proliferation has been proposed in a recent study. However, the mechanisms by which LINC00320 regulate aquaporin 9 (AQP9) in glioma require further exploration. Hence, this study aims to investigate effects of LINC00320 on tumorigenicity of glioma cells and angiogenesis of microvascular endothelial cells (MVECs). Expression of LINC00320 and AQP9 in glioma tissues and cells was measured by reverse transcription–quantitative polymerase chain reaction and Western blot analysis. The relationship among LINC00320, nuclear factor κB subunit 1 (NFKB1) and AQP9 was examined by RNA immunoprecipitation, dual-luciferase reporter gene, and chromatin immunoprecipitation assays. The participation of LINC00320 and AQP9 in glioma cell proliferation and MVEC angiogenesis was analyzed using gain- and loss-of-function approaches. Finally, a nude mouse orthotopic xenograft model of glioma was established to investigate the effects of LINC00320 and AQP9 on glioma growth in vivo. LINC00320 was under-expressed and AQP9 was over-expressed in glioma tissues. Further mechanistic investigation showed that LINC00320 downregulated AQP9 by inhibiting the recruitment of NFKB1 to the promoter region of AQP9. LINC00320 overexpression or AQP9 silencing inhibited the proliferation of glioma cells and angiogenesis of MVECs. Also, upregulation of LINC00320 restrained tumor growth and angiogenesis in xenograft mice by downregulating AQP9. Taken together, LINC00320 acts as a tumor suppressor in glioma, thus presenting a novel therapeutic target.

Highlights

In 2018, there were 296,851 newly diagnosed cases of malignancies of the brain and nervous system reported worldwide, which brought very high mortality (Bray et al, 2018)
Through the computational long non-coding RNAs (lncRNAs)–transcription factors (TFs) gene prediction based on the LncMap database, we proposed in this study a possible interaction among LINC00320, nuclear factor κB subunit 1 (NFKB1), and aquaporin 9 (AQP9)
Identified long non-coding RNAs have emerged as important regulators of many biological processes and molecular mechanisms of the development and progression of devastating brain tumors such as glioma and neuroblastoma (Malissovas et al, 2018; Pop et al, 2018)

Summary

Introduction

In 2018, there were 296,851 newly diagnosed cases of malignancies of the brain and nervous system reported worldwide, which brought very high mortality (Bray et al, 2018). An abundance of identified long non-coding RNAs (lncRNAs) are known to play indispensable roles in the pathogenesis and biological processes of glioma, such as stemness, angiogenesis, and drug resistance (Peng et al, 2018). It has recently been acknowledged that lncRNAs are critical regulators of the transcriptional process, which can bind to DNA binding proteins that are transcription factors (TFs; Long et al, 2017). The AQP water channels have been highlighted as important regulators in nervous system and hold great potential as promising therapeutic targets for brain disorders (Xu et al, 2017). We speculated that LINC00320 might bind to NFKB1 to regulate the transcription of AQP9, which might possibly be involved in the progression of glioma

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