Inducing Apoptosis and Necrosis in Cancer Cells

Apoptosis was induced by exposing epithelial cancer cell lines to UV irradiation at 254 nm for 15 min followed by incubation in RPMI 1640 medium supplemented with 10% FBS for 2 h at 37 °C in 5% CO₂. Necrotic (i.e., lysed) cancer cells were obtained by multiple freeze‒thaw cycles. Apoptosis and necrosis were confirmed by annexin V-FITC/propidium iodide (BD Biosciences, San Jose, CA, USA) staining followed by flow cytometric analysis on a FACSCalibur system (ACEA Novocyte 3000, Agilent, Santa Clara, CA, USA) [18 (link)]. Supplementary Fig. S1a, b show representative dot plots indicating the percentages of apoptotic and necrotic 344SQ and A549 cells.