(A) Logarithmic dose–response curve of alpelisib was performed using the xCELLigence RTCA system. 1, 3, 10, 30, and 100 nM (n = 5 replicates) of alpelisib were used to determine the concentration–response curve. The alpelisib half maximal inhibitory concentration (IC50) was calculated for LM-LEC at 24 hr after treatment as 4.72 × 10−9 M. Error bars are shown as mean +/- standard deviation (SD), which was automatically calculated for each data point by the xCELLigence RTCA system software (Version 2.0) based on five replicates per drug concentration. (B) Illustrative picture of LM-LEC clonogenic plaques at 24 hr after alpelisib treatment (4.72 × 10−9 M). Negative, no treatment; dimethyl sulfoxide (DMSO), vehicle control. Experiments were performed two times with similar results. LM-LEC colonies were stained with crystal violet (0.3%). (C) Colony count 24 hr after alpelisib treatment (4.72 × 10−9 M; n = 2 wells/condition). Error bars are shown as mean +/- SD calculated by GraphPad Prism by determining the square root of variance for each data point deviation relative to the mean.