Pcdna3.1 ctnnb1

A549 and Calu3 cells were cultured in six-well plates (8x10⁵ cells/well) and transfected with plasmids (pcDNA3.1-ctnnb1 or pcDNA3.1-vector; Shanghai GenePharma Co., Ltd.) or mimics (miR-140-3p mimics, 5'-UACCACAGGGUAGAACCACGG-3' or control mimics, 5'-GCAAGAGACAAGCGCUUAGCC-3'; Shanghai GenePharma Co., Ltd.), using Lipofectamine^® 2000 reagent (Invitrogen; Thermo Fisher Scientific, Inc.). Briefly, the plasmids (2 µg) or mimics (50 nM) were added to 200 µl Opti-MEM medium (Gibco; Thermo Fisher Scientific, Inc.) in one vial, whilst 4 µl Lipofectamine^® 2000 was diluted in 200 µl Opti-MEM in another vial. Following incubation for 5 min at room temperature, the contents of both vials were combined and incubated for a further 20 min at room temperature before the mixture was added to the cells. The media in each well was then replaced with fresh medium 6 h following incubation with the transfection mixture at 37˚C. The transfected cells were harvested 48 h later for subsequent experimentation.