<p>LINC00152 knockdown leads to changes in gene expression. A) Heatmap showing clustering of replicates from the same condition (with or without LINC00152 knockdown) based on differentially regulated genes in U87 cells. Three biological replicates for each condition are shown to cluster together. Bootstrap values based on 1000 repetitions are shown near to the corresponding branches. B-G) LINC00152 knockdown decreases BCL2L11 expression, but overexpression of LINC000152 or the M8 hairpin does not upregulate BC2L11 expression. B) qRT-PCR showing knockdown of LINC00152 after treatment with two different siRNAs. C) and D) qRT-PCR of BCL2L11 using two different primer pairs after LINC00152 knockdown. E) qRT-PCR shows overexpression of full length LINC00152 or the M8 hairpin alone. F) and G) Same as C) and D) except after overexpression of LINC00152 or M8.</p>
ARTICLE ABSTRACT
Long noncoding RNAs (lncRNA) are increasingly implicated in oncogenesis. Here, it is determined that LINC00152/CYTOR is upregulated in glioblastoma multiforme (GBM) and aggressive wild-type IDH1/2 grade 2/3 gliomas and upregulation associates with poor patient outcomes. LINC00152 is similarly upregulated in over 10 other cancer types and associates with a poor prognosis in 7 other cancer types. Inhibition of the mostly cytoplasmic LINC00152 decreases, and overexpression increases cellular invasion. LINC00152 knockdown alters the transcription of genes important to epithelial-to-mesenchymal transition (EMT). PARIS and Ribo-seq data, together with secondary structure prediction, identified a protein-bound 121-bp stem-loop structure at the 3′ end of LINC00152 whose overexpression is sufficient to increase invasion of GBM cells. Point mutations in the stem-loop suggest that stem formation in the hairpin is essential for LINC00152 function. LINC00152 has a nearly identical homolog, MIR4435-2HG, which encodes a near identical hairpin, is equally expressed in low-grade glioma (LGG) and GBM, predicts poor patient survival in these tumors, and is also reduced by LINC00152 knockdown. Together, these data reveal that LINC00152 and its homolog MIR4435-2HG associate with aggressive tumors and promote cellular invasion through a mechanism that requires the structural integrity of a hairpin structure.Implications: Frequent upregulation of the lncRNA, LINC00152, in glioblastoma and other tumor types combined with its prognostic potential and ability to promote invasion suggests LINC00152 as a potential biomarker and therapeutic target. Mol Cancer Res; 16(10); 1470–82. ©2018 AACR.
