Figure 2. DT2216 degrades BCL-XL in a VHL- and proteasome-dependent manner.
a, ABT263 and/or VHL-L cannot induce BCL-XL degradation in MOLT4 cells. An immunoblot analysis of BCL-XL in MOLT-4 cells is shown after the cells were treated with ABT263 or VHL-L or the combination of both for 16 h. b, Pretreatment with ABT263 blocks the BCL-XL degradation by DT2216. An immunoblot analysis of BCL-XL in MOLT-4 cells after they were either left untreated or pretreated with ABT263 for 1 h and then treated with or without DT2216 as indicated for 16 h before being assayed. c, Pretreatment with VHL-L blocks the BCL-XL degradation by DT2216. An immunoblot analysis of BCL-XL in MOLT-4 cells is shown. The cells were either left untreated or pretreated with VHL-L for 1 h and then treated with or without DT2216 as indicated for 16 h before being assayed. d, An immunoblot analysis of BCL-XL in VHL-null 786-O cells treated with vehicle (Veh) or increasing concentrations of DT2216 for 16 h. e, An immunoblot analysis of BCL-XL in MOLT-4 cells is shown. The cells were treated with 1 μM of DT2216 and its negative-control DT2216NC for 16 h before being assayed. f, Proteasome inhibition blocks the BCL-XL degradation by DT2216. A representative of two immunoblot analyses of BCL-XL in MOLT-4 cells after they were either left untreated or pretreated with the proteasome inhibitor MG132 for 1 h, and then treated with or without DT2216 for 16 h. g, Cell viability of MOLT-4 cells treated with or without ABT263 in the presence or absence of VHL-L for 72 h. h, Cell viability of MOLT-4 cells after they were either left untreated or pretreated with VHL-L for 1 h, and then treated with DT2216 for 72 h. The data presented in g and h are mean ± SD from three replicate cell cultures in one representative experiment. Each symbol represents data from an individual replicate. Similar results were obtained in an additional independent experiment. i, Cell viability of MOLT-4 cells after treatment with increasing concentrations of DT2216 or its negative-control DT2216NC for 72 h. The data represent mean ± SD from six replicate cell cultures in one representative experiment. Each symbol represents data from an individual replicate. Similar results were obtained in one additional independent experiment. β-actin was used as an equal loading control in immunoblot analyses shown in Fig. 2a–f. The uncropped immunoblot images related to this figure are provided in separate source data file.