A library of 515 commercially available chemotherapeutic and targeted oncology compounds consisted of 168 approved drugs, 261 investigational compounds, and 86 probes (Supplementary Table S2). The chemical compounds DMSO (negative control) and benzethonium chloride (positive control) were added to 384-well plates using an acoustic liquid dispensing system Echo 500/550 (Labcyte). Freshly isolated MNCs were counted and resuspended in MCM (PromoCell) with 0.5 μg/mL gentamicin and 2.5 μg/mL amphotericin or in CM constituted of 77.5% RPMI 1640, 10% FCS, 12.5% human HS-5 bone marrow stromal cell line–derived CM, and 1% penicillin and streptomycin. A 5-μL cell-free medium was added to dissolve compounds followed by 20 μL cell suspension containing 5,000 to 10,000 cells to each well using multidrop (Thermo Fisher). The plates were incubated at 37°C in 5% CO2 for 72 hours. Subsequently, CellTiter-Glo (Promega) reagent was added to all wells, and cell viability as luminescence generated by total cellular ATP was measured using a PHERAstar (BMG Labtech).
The drug responses passing the data quality assessment were included in further analysis (45 (link)). DSS were calculated as shown previously (30 (link)) and sDSS were calculated by normalizing drug responses against 17 healthy controls.