Effects of SQE, p-coumaric acid, and tricin on self-renewal characteristics of colon CSCs. CD133+CD44+ HT29 cells (a) and CD133+CD44+ HCT116 cells (b) were treated with SQE (0, 100, 200, or 300 μg/mL), or p-coumaric acid (1.8 μM) and tricin (0.7 μM) at concentrations equivalent to that contained in 300 μg/mL SQE. (A) After eight days, the resulting colonies were fixed and stained. Microscopy images of colony formation were obtained (magnification, 100×, left panel) and the number of colonies was recorded (right panel). Plating efficiency (%) = (number of colonies)/(total cell number) × 100; (B) Sphere formation was analyzed for both cell lines and images were obtained with phase contrast microscopy (left panel, magnification, 100×). The number of spheres was recorded (right panel). The letter labels on the histogram indicate the values that significantly differed from each other (p < 0.05) according to one-way ANOVA for multiple comparisons. Ctrl, Control; SQE, Sasa quelpaertensis extract; P.C, p-coumaric acid; T, tricin.