ABCG2 and cancer: To further address the ABCG2 dependence of the combined effect of SCO-101 with anti-cancer drugs, we employed a cellular model (HL-60 cells) of acute promyelocytic leukemia (AML) with low ABCG2 expression (using ABCG2 expression in HT29SN-38 cells as baseline (Figure S5A)), in which ABCG2 was stably re-expressed (HL-60ABCG2 cells) [41,42] (Figure 7A and Figure S5B).