KLF2 luciferase assay was performed as follow. Briefly, COS-7 cells at a density of 80–90% in 100-mm dish were transfected with 5.4 µg plasmid (KLF2-luc or KLF2 -221 WT or KLF2 -221 mutant plasmid) using lipofectamine 2000 (Thermo Fisher Scientific, USA) in Opti-MEM (Gibco) for 6 h. Then the transfected cells were grown in 96-well plates (3.5 × 105 cells/well, 100 µl/well). After 6 h, 1.0 µl /well drugs at a final concentration of 5 µM in 200 µl medium/well were added and incubated for 24 h. The KLF2 luciferase reporter gene activity was detected using Promega dual-luciferase reporter 1000 assay system in a microplate spectrophotometer (BMG, USA). The luciferase activity of the tested compound is as calculated as compound firefly luciferase value/DMSO firefly luciferase value.