Figure 3.

IB-DNQ treatment preferentially inhibits CSC activity in TNBC cells expressing NQO1. A–D, Tumorsphere formation of Vari068 (A) and SUM159 (C) breast cancer cells in medium containing control (DMSO) or IB-DNQ of various doses, and relative survival of Vari068 (B) and SUM159 (D) cells grown in adherent culture with IB-DNQ for 14 days, n = 6 wells. E and F, Sphere formation of Vari068 cells subjected to Dox-induced KD of NQO1, CAT, SOD1, or SOD2 and IB-DNQ treatment (E) and the impact of KD on IB-DNQ suppression of sphere-forming capacity (F). G–N, Vari068 (G–J) and SUM149 (K–N) cells were treated with indicated compounds for 20 hours and examined for the content and absolute number of ALDH⁺ and CD24⁻CD44⁺ CSCs. *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001 vs. control or indicated by brackets. n = 3, one-way ANOVA for A, C, F, G–J, and K–N.