Cell viability assay

Cells were plated in 96-well plates at a seeding density of 3000 cells/well. The cells were left to adhere overnight. A549 and H1299 cells treated with aaptamine of 0, 3.125, 6.25, 12.5, 25 and 50 μg/mL for 48 h. Add 10 μL of CCK-8 solution to each well of the plate and then incubate the plate for 4 h in the incubator. Measure the absorbance at 450 and 630 nm using a microplate reader (Bio-Rad, Fitchburg, WI). The half-maximal inhibitory concentration (IC₅₀) of aaptamine in A549 and H1299 cells was calculated using Graphpad Prism version 7 (GraphPad Software, La Jolla, CA). In the cell proliferation analysis, CCK-8 test was performed 12, 24, 36, 48, 60 and 72 h after A549 and H1299 cells treatment with various concentrations (0, 8, 16 and 32 μg/mL) of aaptamine. Cell viability was calculated as the relative absorbance compared to control absorbance. All experiments were repeated three times in three wells of the microplate. All experiments were repeated three times in three wells of the microplate (Chen et al. 2018).