Fig. 4

Pharmacological inhibition of thioredoxin by PX12 triggers mitophagy in BTZ-resistant multiple myeloma cells. a Western blot analyses of LC3B and PINK1 expression in MM.1R-BTZ-resistant cells treated with BTZ (5 nM), PX12 (2.5 μM), or BTZ+PX12 after 48 h of incubation. b Western blot analyses of LC3B and PINK1 expression in RPMI8226/Dox-BTZ-resistant cells treated with BTZ (5 nM), PX12 (2.5 μM), or BTZ+PX12 after 48 h of incubation. c Representative transmission electron microscopy images of mitochondria network in MM.1R-BTZ-resistant cells treated with BTZ (5 nM) for 48 h. d Representative transmission electron microscopy images of mitochondria network in MM.1R-BTZ-resistant cells treated with BTZ (5 nM) and PX12 (2.5 μM) combination for 48 h. Asterisk indicates mitochondria, while number sign indicates lysosomes. Scale bar: 500 nm. e–h The JC-1 fluorescence intensity in MM.1R-BTZ-resistant cells treated with BTZ (5 nM), PX12 (2.5 μM), or BTZ+PX12 were analyzed using flow cytometer. i Western blot analyses of LC3B and PINK1 expression in BTZ-resistant MM.1R tumor dissected from sacrificed mice treated with BTZ (0.5 mg/kg), PX12 (12 mg/kg), or the combination. j Cell viability of MM.1R-BTZ-resistant cells treated with BTZ (5 nM) or/and PX12 (2.5 μM) with or without bafilomycin (0.5 nM). k Cell viability of RPMI8226/Dox-BTZ-resistant cells treated with BTZ (5 nM) or/and PX12 (2.5 μM) with or without bafilomycin (0.5 nM). The intensity of expression was semi-quantitated using Image-Pro Plus 6.0 software and adjusted to β-actin. Error bars, standard error of the mean (SEM); *p < 0.05, **p < 0.01, ***p < 0.005, ****p < 0.001