(A) Establishment of NCAM- or LacZ-expressing cells using two multiple myeloma (MM) cell lines, KMS-11 and NOP-1. Black area, CD56-PE; gray area, isotype. (B) Viability of NCAM- or LacZ-expressing cell lines after exposure to different concentrations of Btz for 16 h. (C) Evaluation of the percentage of NCAM- or LacZ-expressing cells undergoing specific apoptosis after exposure to Btz. (D) Establishment of NCAM knock-down cells using the OPM-2 cell lineage. Black area, cells transfected of negative (non-specific) miRNA cells; gray area, cells transfected to express NCAM-specific miRNA. (E) Evaluation of the proportion of NCAM knock-down cells undergoing apoptosis compared to that among control (miRNA-negative) cells after exposure to the indicated dose of Btz. * indicates statistical significance (p < 0.05), as calculated by student t-test.