Cytotoxicity Evaluation of Cancer Drugs

For lung cancer cell lines, cells were seeded in 96‐well plates and incubated at 37 °C for 24 h. Then cells were incubated with 200 µL of medium containing increasing doses of the drugs gefitinib (Selleckchem Houston, TX), erlotinib (Selleckchem Houston, TX), afatinib (Selleckchem Houston, TX), crizotinib (Selleckchem Houston, TX), or cisplatin (Sigma‐Aldrich, St Louis, MO) for 72 h. To detect and calculate the half maximal inhibitory concentration (IC₅₀), 5 mg mL⁻¹ of (MTT) (Sigma‐Aldrich, St Louis, MO) was added and the mixture was incubated at 37 °C for 4 h. The absorbance was determined at 570 nm. For organoids assays, organoids were dissociated by mechanical shearing, strained through a 70 µm filter, resuspended using LOM medium containing 5% GFR‐BME, and finally 30 µL of suspension were seeded into 384‐well plate. Organoids were treated with increasing concentrations of drugs for 5 days. Cell viability was detected by Cell titer–Glo 2.0 assay kit (Promega) and luminescence were measured by a multifunctional reader. The drug response curve was plotted and IC₅₀ was calculated using nonlinear regression model by GraphPad Prism 7.0.