(
A) PC9 cells were plated at equal density and treated with DMSO or the indicated dose of erlotinib HCl (2 or 20 µM) for 9 days (fresh erlotinib was added every 3 days). Representative microscopic images of conditions on day 9. (
B) Percent of drug-tolerant persisters (DTPs) as a percentage of DMSO control cells. PC9 cells were plated at various densities (cells/cm
2) and treated with DMSO or the indicated concentrations of erlotinib HCl. (
C) Survival curve of PC9 cells treated with various doses of erlotinib for 72 hr. Percent survival is relative to DMSO-treated cells. The dashed line corresponds to 50% cell killing (absolute IC
50 = 0.15 µM). Each experiment was performed once. Additional details can be found at
https://osf.io/xbign/.