Long Noncoding RNA SChLAP1 Forms a Growth-Promoting Complex with HNRNPL in Human Glioblastoma through Stabilization of ACTN4 and Activation of NF-kappa B Signaling

Ji, JX; Xu, R; Ding, KK; Bao, GQ; Zhang, X; Huang, B; Wang, XY; Martinez, A; Wang, XY; Li, G; Miletic, H; Thorsen, F; Bjerkvig, R; Xiang, L; Han, B; Chen, AJ; Li, XA; Wang, J

Chen, AJ; Li, XA (reprint author), Shandong Univ, Qilu Hosp, Dept Neurosurg, 107 Wenhua Xi Rd, Jinan, Shandong, Peoples R China.; Chen, AJ; Li, XA (reprint author), Shandong Univ, Brain Sci Res Inst, Key Lab Brain Funct Remodeling, 107 Wenhua Xi Rd, Jinan

CLINICAL CANCER RESEARCH, 2019; 25 (22): 6868

Abstract

Purpose: Long noncoding RNAs (lncRNA) have essential roles in diverse cellular processes, both in normal and diseased cell types, and thus have emerged as potential therapeutic targets. Aspecific member of this family, the SWI/SNF complex antagonist associated with prostate cancer 1 (SChLAP1), has been shown to promote aggressive prostate cancer growth by antagonizing the SWI/SNF complex and therefore serves as a biomarker for poor prognosis. Here, we investigated whether SChLAP1 plays a potential role in the development of human glioblastoma (GBM). Experimental Design: RNA-ISH and IHC were performed on a tissue microarray to assess expression of SChLAP1 and associated proteins in human gliomas. Proteins complexed with SChLAP1 were identified using RNA pull-down and mass spectrometry. Lentiviral constructs were used for functional analysis in vitro and in vivo. Results: SChLAP1 was increased in primary GBM samples and cell lines, and knockdown of the lncRNA suppressed growth. SChLAP1 was found to bind heterogeneous nuclear ribonucleoprotein L (HNRNPL), which stabilized the lncRNA and led to an enhanced interaction with the protein actinin alpha 4 (ACTN4). ACTN4 was also highly expressed in primary GBM samples and was associated with poorer overall survival in glioma patients. The SChLAP1-HNRNPL complex led to stabilization of ACTN4 through suppression of proteasomal degradation, which resulted in increased nuclear localization of the p65 subunit of NF-kappa B and activation of NF-kappa B signaling, a pathway associated with cancer development. Conclusions: Our results implicated SChLAP1 as a driver of GBM growth as well as a potential therapeutic target in treatment of the disease.

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