Figure 3

Manipulation of APE1 affects cell resistance to melphalan. (A) APE1 protein levels at 48 hours post transfection of siRNA or overexpression vector in RPMI-8226 cells were measured using Western blot. Transfection reagent only treated cells were included as a control. (B) Cell survival after 24, 48 and 72 hours post 15 μM melphalan treatment in all three groups was measured using CCK-8 assay. A star (*) represents that the difference between the shAPE1 transfected group and the vehicle alone group is statistically significant (p < 0.05), # represents that the difference between pcDNA-wtAPE1 transfected group and vehicle alone group is statistically significant (p < 0.05). (C) APE1 knockdown in RPMI-8226/LR5 partially restored the sensitivity to melphalan. The results shown in the bar graph indicated the cell viability in different groups after melphalan treatment using the CCK-8 assay. The representative Western blots show APE1 was effectively knocked down in RPMI-8226/LR5 by siRNA transfection. A star (*) represents that the difference between siAPE1 and vehicle alone transfected RPMI-8226/LR5 is statistically significant (p < 0.05), # represents that the difference between shAPE1 transfected RPMI-8226/LR5 and vehicle alone transfected RPMI-8226 is statistically significant (p < 0.05). All results were from three independent experiments.