Figure 1.

LBH589 induces cytotoxicity in human MM cell lines resistant to conventional chemotherapy. (A) Viability of MM.1S, RPMI8226, U266, OPM1, and KMS11 at 48 hours was inhibited by LBH589 in a dose-dependent manner as demonstrated by MTS assay. (B) Growth of Dex-resistant MM.1R cells and RPMI8226 MM cells resistant to Dox (Dox40 cells), Mit (MR20 cells), or Mel (LR5 cells) was inhibited in a dose-dependent manner, as demonstrated by MTS assay. (C) Adhesion of MM.1S cells to BMSCs induced a significant increase in ³H-thymidine uptake by MM.1S cells at 48 hours, which was completely inhibited by LBH589. Supernatants from the experiment (C) were examined for cytokine secretion (D). LBH589 inhibited adhesion-induced up-regulation of IL-6 secretion in BMSCs triggered by coculture with MM.1S. (E) LBH589 up to 1 μM decreased BMSC viability, with 61% viability at 48 hours and 59% viability at 72 hours. Data represent mean ± SD of quadruplicate cultures.