Azaspirane induces growth inhibition in MM cell lines and patient MM cells. (A) MM.1S (♦), U266 (▪), and RPMI8226 (▴) MM cells; (B) Dex-sensitive MM.1S (♦) and Dex-resistant MM.1R (▪) MM cells; (C) drug-sensitive RPMI8226 (♦), melphalan-resistant RPMI-LR5 (▪), and doxorubicin-resistant RPMI-Dox40 (▴) cells; (D) OPM1 (▴), INA-6 (▪), and MM.1S (♦) cells; (E) freshly isolated tumor cells from patients with MM (n = 3; ▪, , □), as well as (F) peripheral blood mononuclear cells from healthy volunteers (n = 3; ▪, ▴, ♦) were cultured for 48 hours in the presence of azaspirane (0-5 μM). Cell growth was assessed by MTT assay, and data represent mean (± SD) of quadruplicate cultures.