E2F1-Induced Overexpression of Long Noncoding RNA SBF2-AS1 Promotes Non-Small-Cell Lung Cancer Metastasis Through...

Long noncoding RNA SBF2 antisense RNA 1 (lncRNA SBF2-AS1) has been reported to be involved in non-small-cell lung cancer (NSCLC) tumorigenesis. However, the biological role and regulatory mechanism of lncRNA SBF2-AS1 on NSCLC metastasis remain largely unknown. In this study, the expression level and functional role of SBF2-AS1 were investigated in both NSCLC tissues and cell lines. We found that SBF2-AS1 was upregulated in both NSCLC tissues and cell lines. Patients with high levels of SBF2-AS1 have larger tumors, higher malignancy, and poor prognosis. Knockdown of SBF2-AS1 significantly inhibited tumor growth in vivo and cell proliferation, migration, and invasion in vitro. Moreover, bioinformatics analysis, chromatin immunoprecipitation assay, and luciferase reporter assay proved that the upregulation of SBF2-AS1 was mediated by transcription factor E2F1. Further experiments demonstrated that miR-362-3p had complementary binding site with 3'-UTR of SBF2-AS1. Besides, luciferase reporter assay validated that GRB2 was the target protein of miR-362-3p. Rescue experiments showed that SBF2-AS1 silencing inhibited cell invasion and migration, while cotransfection si-SBF2-AS1 and miR-362-3p inhibitor rescued the effect of si-SBF2-AS1. These results demonstrate that E2F1-induced overexpression of SBF2-AS1 promotes the expression of GRB2 by targeting miR-362-3p to facilitate the metastasis of NSCLC.