Fig. 4. Identification of UM4118 as a potent and selective analog of S767.
(A) Structures of S767 [C7-locked N-(quinoline-8-yl)benzenesulfonamide], UM4118 [N-(quinoline-8-yl)picolinamide], and UM3903 [N-(quinoline-8-yl)benzamide] with IC50 values in OCI-AML5 cells. Ratio of IC50 values obtained in OCI-AML5 stably expressing shRNA control over shRNA ABCB7 is indicated. (B) Ultraviolet-visible spectrum of S767, UM4118 and UM3903 (40 μM) alone and in the presence of indicated metals (40 μM) in ethanol at room temperature. (C) Intracellular metal quantification by ICP-MS in OCI-AML5 cells exposed 3 hours to indicated compounds with and without 100 μM the non-cell permeable copper chelator BCS. Data are represented as mean ± SD (n = 3, unpaired t test compared to DMSO condition). (D) Immunoblot of γH2A.X and phospho-p53 at serine 15 from OCI-AML5 cells treated 24 hours with S767 analogs or elesclomol. For each compound, a concentration corresponding to 12 times the IC50 was used. Tubulin is used as a loading control.