MCL1 and leukemia: In SUP-T1 cells, apart from downregulation of the known BRD4 targets like Myc, Bcl-2, Bcl-XL, and Mcl-1, treatment with ARV-825 substantially decreased the expression of key molecules involved in leukemia persistence, such as HES1 (a direct target of Notch1), PI3K/AKT pathway proteins, and CD44 (Fig. 3A left panel).