Dual-luciferase reporter assay

The miRNAs that might interact with circ_0079530 were predicted by circInteractome (https://circinteractome.nia.nih.gov/) and starBase (http://starbase.sysu.edu.cn/), and the targets of miR-409-3p were predicted by starBase. The wild-type (WT) sequence of circ_0079530 or AQP4 3’UTR with miR-409-3p binding sites was introduced in the pmir-GLO vector (Promega, Madison, WI, USA), acquiring the WT-circ_0079530 and WT-3’UTR AQP4 vectors. Also, mutant (MUT)-circ_0079530 and MUT-3’UTR AQP4 vectors were constructed using the sequence containing the MUT binding sites of miR-409-3p. The constructed vectors were co-transfected with miR-409-3p mimic or miR-NC into H2170 and A549 cells, followed by analysis using a dual-luciferase reporter assay kit (Promega) according to the instructions.