Potentiation of antileukemic therapies by Smac mimetic, LBW242: effects on mutant FLT3-expressing cells

Effects of LBW242 plus PKC412 on proliferation of PKC412-sensitive and PKC412-resistant mutant FLT3-expressing cells. A, proliferation study showing 3-d treatments of FLT3-ITD-W51-Ba/F3 cells with PKC412, LBW242, or a combination of PKC412 and LBW242 (study shown is representative of three independent experiments). B, proliferation study showing 3-d treatments of A627T-Ba/F3 cells with PKC412, LBW242, or a combination of PKC412 and LBW242 (n = 1). C, proliferation study showing 3-d treatments of F691I-Ba/F3 cells with PKC412, LBW242, or a combination of PKC412 and LBW242 (n = 1). D, proliferation study showing 3-d treatments of G697R-Ba/F3 cells with PKC412, LBW242, or a combination of PKC412 and LBW242 (study shown is representative of two independent experiments).

Effects of LBW242 plus doxorubicin or Ara-c, respectively, on proliferation of PKC412-sensitive and PKC412-resistant mutant FLT3-expressing cells. A, proliferation study showing 3-d treatments of FLT3-ITD-Ba/F3 cells with doxorubicin, LBW242, or a combination of doxorubicin and LBW242 (n = 1). B, proliferation study showing 3-d treatments of A627T-Ba/F3 cells with doxorubicin, LBW242, or a combination of doxorubicin and LBW242 (n = 1). C, proliferation study showing 3-d treatments of FLT3-ITD-Ba/F3 cells with Ara-c, LBW242, or a combination of Ara-c and LBW242 (n = 1). D, proliferation study showing 3-d treatments of F691I-Ba/F3 cells with Ara-c, LBW242, or a combination of Ara-c and LBW242 (n = 1).

In vivo investigation of combined effects of PKC412 and LBW242. A–C, NCR nude mice injected with 800,000 Ba/F3-FLT3-ITD-luc+ cells via i.v. tail vein and then treated for up to 10 d by oral gavage with vehicle (NMP + PEG300), LBW242 (50 mg/kg) alone, PKC412 (40 mg/kg) alone, or a combination of LBW242 (50 mg/kg) and PKC412 (40 mg/kg). Mice were sacrificed 8 d after the last imaging day, spleen and total weights were measured, and mice were preserved in 10% formalin for histopathologic analysis. A, mouse photos show bioluminescence of mice following 7 d post-i.v. injection. B, bioluminescence, as shown in A, presented as percent baseline. C, percent spleen weights of mice treated for 10 d with LBW242, PKC412, or a combination of LBW242 and PKC412. D and E, NCR nude mice injected with 800,000 Ba/F3-FLT3-ITD-luc+ cells via i.v. tail vein and then treated for up to 6 d by oral gavage with vehicle (NMP + PEG300), LBW242 (50 mg/kg) alone, PKC412 (40 mg/kg) alone, or a combination of LBW242 (50 mg/kg) and PKC412 (40 mg/kg). Mice were sacrificed on the last imaging day (day 7 post-i.v. injection) and preserved in 10% formalin for histopathologic analysis. D, mouse photos show bioluminescence of mice following 7 d post-i.v. injection. E, bioluminescence, as shown in D, presented as percent baseline.