2.2. Flow cytometric analysis of cell cycle with propidium iodide DNA staining

Сells were cultured in a 25‐cm² flask and treated with dacarbazine for 72 h at 37°C at a concentration of 1.2 or 2.4 mM. After 72 h, the cells were washed with PBS, and fresh medium without the aforementioned compound was added and incubated for a further 48 h to allow the transition of cells into G₀, which happens within 5 days after incubation with a chemotherapeutic drug in accordance with the literature, whereas apoptotic cells should be eliminated. ^{26 , 27} DMSO‐treated cells were used as a control. Next, the cell suspensions were washed with PBS, fixed with 70% ice‐cold ethanol, treated with RNase A (100 μg/ml) (Invitrogen; Thermo Fisher Scientific, Inc.) for 30 min, stained with propidium iodide (PI; 100 μg/ml) for 30 min at 37°C in the dark and subjected to flow cytometry using a Cytomics FC‐500 flow cytometer (Beckman Coulter, Inc.). The experiments were performed three times.