Blocking lncRNA MALAT1/miR-199a/ZHX1 Axis Inhibits Glioblastoma Proliferation and Progression

Keman Liao,Yingying Lin,Weizhen Gao,Zhipeng Xiao,Rogelio Medina,Pauline Dmitriev,Jing Cui,Zhengping Zhuang,Xiaochun Zhao,Yongming Qiu,Xiaohua Zhang,Jianwei Ge,Liemei Guo

doi:10.1016/j.omtn.2019.09.005

Abstract

Zinc fingers and homeoboxes 1 (ZHX1) is a transcription repressor that has been implicated in the tumorigenesis and progression of diverse tumors. The functional role and regulating mechanism of ZHX1 has not been elucidated in glioblastoma (GBM). Previous reports have suggested that a large number of non-coding RNAs play a vital role in glioma initiation and progression. This study aimed to investigate the functional role and co-regulatory mechanisms of the metastasis-associated lung adenocarcinoma transcript-1 (MALAT1)/ microRNA-199a (miR-199a)/ZHX1 axis in GBM. We analyzed the expression of the MALAT1/miR-199a/ZHX1 axis and its correlation with patients’ overall survival using two different glioma gene-expression datasets. A series of in vitro and in vivo studies including dual luciferase reporter assay, fluorescence in situ hybridization (FISH), RNA immunoprecipitation, and pull-down experiments were completed to elucidate the biological significance of the MALAT1/miR-199a/ZHX1 axis in promoting glioma proliferation and progression. Elevated ZHX1 expression correlated with poor prognosis in GBM patients, and in vitro studies demonstrated that ZHX1 attenuated GBM cell apoptosis by downregulation of pro-apoptotic protein (Bax) and upregulation of anti-apoptotic protein (Bcl-2). Furthermore, knockdown of MALAT1 inhibited GBM proliferation and progression in vitro and reduced tumor volume and prolonged survival in an orthotopic GBM murine model. Finally, we demonstrated that MALAT1 promoted ZHX1 expression via acting as a competing endogenous RNA by sponging miR-199a. The MALAT1/miR-199a/ZHX1 axis promotes GBM cell proliferation and progression in vitro and in vivo, and its expression negatively correlates with GBM patient survival. Blocking the MALAT1/miR-199a/ZHX1 axis can serve as a novel therapeutic strategy for treating GBM.

Highlights

Glioblastoma (GBM) is the most prevalent and aggressive primary malignant brain tumor with a median survival of 14.6 months.[1]
Kaplan-Meier analysis revealed that GBM patients with high Zinc fingers and homeoboxes 1 (ZHX1) expression (30% upper percentile, n = 45) survived longer than the patients with low ZHX1 expression (30% lower percentile, n = 45) (Figure 1D; p = 0.0409)
In summary, our study demonstrated that elevated ZHX1 expression in GBM tissue was correlated with poor prognosis for GBM patients

Summary

Introduction

Glioblastoma (GBM) is the most prevalent and aggressive primary malignant brain tumor with a median survival of 14.6 months.[1]. Zinc fingers and homeoboxes 1 (ZHX1) is a nuclear transcription repressor that interacts with the A subunit of nuclear factor-Y (NFYA) and contains two C2H2-type zinc fingers and five homeobox DNA-binding domains.[5] This protein has recently been implicated in the carcinogenesis of various cancers, including GBM.[6,7,8] The mechanisms behind ZHX1’s potentially carcinogenic role have not been clearly elucidated, and previous reports suggest that ZHX1 may have both pro- and anti-carcinogenic functions among different cancer types. Kwon et al.[8,9] reported that ZHX1 expression levels positively correlated with increased proliferation, migration, and invasion of GBM and cholangiocarcinoma cells. Wang et al.[11] described that ZHX1 expression was reduced among cancer tissues from hepatocellular carcinoma patients, and overexpression of ZHX1 could inhibit the proliferation of hepatocellular carcinoma cells. The exact function of ZHX1 in carcinogenesis is not completely

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