miR-421 promoted migration and invasion of lung adenocarcinoma (LUAD) by the circ_0000567/miR-421/TMEM100 competing endogenous RNA network. A Schematic of the screening procedure of candidate genes. FMO2, CLDN18, TMEM100, LDB2, CAV1, and SPINK1 were predicted using TargetScan, miRanda, MirDB, or miRpath websites, and were downregulated in LUAD patients from the Gene Expression Omnibus database. B
TMEM100 was upregulated when A549 cells were transfected with miR-421 inhibitor and downregulated when PC9 cells were transfected with miR-421 mimics. *P<0.05, ***P<0.001. The expression of FMO2, CLDN18, LDB2, CAV1, and SPINK1 did not change significantly in PC9 and A549 cells. C Schematic of TMEM100 wild-type (WT) and mutant luciferase reporter vectors. D Luciferase activities of WT and mutant TMEM100 after co-transfection with miR-421 mimics. E
TMEM100 was downregulated in 73 LUAD. specimens compared to the paired normal lung tissues (P=0.0098). F The expression of miR-421 was inversely proportional to that of TMEM100 in 73 LUAD tissues. G The expression of TMEM100 was directly proportional to circ_0000567 in 73 LUAD tissues. H The expression of TMEM100 was upregulated when circ_0000567 was overexpressed in A549 cell lines.