Fig. 4. PLK1 inhibition perturbed the cell cycle. A-B. Diploid and tetraploid human colorectal carcinoma RKO cells were treated with DMSO or 10 nM Bi2536. After 24, 48 or 72 h, the cells were collected and fixed with cold 75% ethanol. The fixed cells were further labelled with propidium iodide (PI), followed by the assessment of cell cycle distribution. A representative histogram and quantitative data are represented.