2.7. Colony Formation Assay

After 24 h of transfection, A549 cells were inoculated into a 6-well plate with 1 × 10³ cells/well, and each treatment group was made in triplicate. Cells were cultured in a complete medium for one week until clear colonies were formed. Cell colonies were fixed with 70% methanol for 5 min and stained with 0.5% crystal violet (Thermo Fisher, USA). Each well was washed with sterile water to remove residual crystal violet. Colonies with more than 50 cells were identified, and the number of colonies per well was calculated.