Figure 1

Effects of YM155 on neuroblastoma cell viability and the role of ABCB1 and SLC35F2 expression. (a) YM155 concentrations that reduce the viability of the investigated neuroblastoma cell lines by 50% (IC50) as determined by MTT assay after a 120 h incubation period (numerical values are presented in Supplementary Table 1). *P<0.05 relative to the respective parental cell line; (b) Cellular ABCB1 levels as indicated by quantitative, fluorescence-based western blot analysis; values are presented as fold change relative to the respective parental cell line. Representative western blots are provided in Supplementary Figure 2. *P<0.05 relative to the respective parental cell line; (c) YM155 IC50s as determined by MTT assay after a 120 h incubation period in the presence of the ABCB1 inhibitor verapamil (5 μM) in the parental cell lines UKF-NB-3 and UKF-NB-6 and their ABCB1-expressing sublines UKF-NB-3^rVCR¹⁰, UKF-NB-6^rDOX²⁰, and UKF-NB-6^rVCR¹⁰ (numerical values are presented in Supplementary Table 1). *P<0.05 relative to the respective parental cell line; (d) YM155 IC50s as determined by MTT assay after a 120 h incubation in UKF-NB-3 or UKF-NB-6 cells transduced with a lentiviral vector encoding for ABCB1 or an empty control vector (piCER2). *P<0.05 relative to the respective control vector-transduced cell line; (e) Cellular SLC35F2 levels as indicated by quantitative, fluorescence-based western blot analysis; values are presented as fold change relative to the respective parental cell line. Representative western blots are provided in Supplementary Figure 2. *P<0.05 relative to the respective parental cell line; (f) Western blot indicating SLC35F2 depletion in UKF-NB-3 cells by three lentiviral vectors encoding for shRNA directed against three different sequences of SLC35F2 (sh1 SLC, sh2 SLC, sh3 SLC) relative to untreated and empty control vector-treated (control) UKF-NB-3 cells and bar chart indicating YM155 concentrations that reduce the viability of these cell lines by 50% (IC50) as indicated by MTT assay after 120 h of incubation. Numerical IC50 values are presented in Supplementary Table 2. *P<0.05 relative to non-treated cells; (g) Western blots indicating siRNA-mediated SLC35F2 depletion (scr siRNA, non-targeting ‘scrambled’ siRNA) and bar chart displaying YM155 IC50 values (as indicated by MTT assay after 120 h of incubation) in UKF-NB-3 and ABCB1-transduced UKF-NB-3 (UKF-NB-3^ABCB1) cells with or without transfection by siRNA directed against SLC35F2. Numerical values and controls transfected with non-targeting siRNA are presented in Supplementary Table 3. *P<0.05 relative to the respective non-transfected cells