In vitro and in vivo activity of NVP-LDE225 alone and in combination with bortezomib. (A) OPM1 cells were treated for 24 hours with 5μM NVP-LDE225 as single agent or in combination with 5nM or 10nM of bortezomib. MM cell viability was assessed by MTT. (B) To evaluate the in vivo antitumor efficacy of NVP-LDE225, we used a mouse subcutaneous xenograft model of MM. CB-17 SCID mice were subcutaneously inoculated with OPM1 cells and treated with vehicle alone, NVP-LDE225, bortezomib, and the combination as detailed in “Methods.” In vivo study showed an increased antitumor activity by the combination compared to bortezomib alone.