Abstract
Background: Accumulating evidences revealed that long noncoding RNAs (lncRNAs) have been participated in cancer malignant progression, including glioblastoma multiforme (GBM). Despite much studies have found the precise biological role in the regulatory mechanisms of GBM,however the molecular mechanisms,particularly upstream mechanisms still need further elucidated. Methods: RT-QPCR, cell transfection, western blotting and bioinformatic analysis were executed to detect the expression of EGR1, HNF1A-AS1, miR-22-3p and ENO1 in GBM. Cell proliferation assay, colony formation assay, wound healing, migration and invasion assays were performed to detect the malignant characters of GBM cell. The molecular regulation mechanism was confirmed by luciferase reporter assay, ChIP and RIP. Finally, orthotopic mouse models were established to examine the effect of HNF1A-AS1 in vivo.Results: In the current study, we analyzed clinical samples to show that the long non-coding antisense transcript of HNF1A, HNF1A-AS1, is upregulated and associated with poor prognosis in GBM. Functional studies revealed that knockdown of HNF1A-AS1 markedly inhibits cell proliferation, migration and invasion both in vitro and in vivo, whereas overexpression of HNF1A-AS1 exerts opposite effect. Mechanistically, the transcription factor EGR1 forced the transcription of HNF1A-AS1 by directly binding the promoter region of HNF1A-AS1. Furthermore, combined bioinformatics analysis with our mechanistic work, using luciferase reporter assays and RIP, we first demonstrated that HNF1A-AS1 functions as a competing endogenous RNA (ceRNA) with miR-22-3p to regulate ENO1 expression in GBM cells. HNF1A-AS1 directly binds to miR-22-3p and significantly inhibits miR-22-3p expression, while ENO1 expression was increased. miR-22-3p inhibitor offsets the HNF1A-AS1 silencing induced suppression in proliferation, migration and invasion of GBM cells, as well as promotion effect on ENO1 expression. ENO1 was verified as a direct target of miR-22-3p and its expression levels was negatively with the prognosis in GBM patients. Conclusion: Taken together, our study illuminated the definite mechanism of HNF1A-AS1 in promoting GBM malignancy, and provided a novel therapeutic target for further clinical application.