Identifying Drug Sensitivity Modifiers

A375-Cas9 cells were infected in four biological replicates. Small molecules were added to puromycin-selected cells 7 days post-infection. Cells either received a media change or were passaged every two or three days over the course of the screen in complete media supplemented with 1% penicillin/streptomycin. Vemurafenib (PLX-4032, Selleckchem, S1267) was screened at a final concentration of 2 μM. Selumetinib (AZD-6244, Selleckchem, S1008) was screened at a final concentration of 200 nM. 6-thioguanine (Sigma A4660) was screened at a final concentration of 2 μg/mL. Etoposide (Sigma E1383) was screened at a final concentration of 1 μg/mL. Surviving cells were harvested after 14 days of small molecule treatment. For analysis, the log₂-fold-change of each sgRNA was determined relative to control cells treated with DMSO.