Fig. 3

HCQ reverses drug sequestration in lysosomes by increasing the lysosomal pH to inactivate P-gp. a PBS- or HCQ-pre-treated A549 cells were treated with DOX (2 μg/ml, 2 h). The cells were stained with LAMP2 and analysed under a two-photon confocal microscope. Scale bar, 10 μm. b The viability of TFEB-silenced A549 cells treated with 0.5 μg/mL DOX for 24 h. c The viability of TFEB-silenced A549 cells treated with DOX or DOX combined with HCQ for 24 h. d TFEB-silenced (or not) A549 cells were treated with DOX (2 μg/ml, 2 h). The cells were stained with LAMP2 and analysed under a two-photon confocal microscope. Scale bar, 10 μm. e PBS- or HCQ-pre-treated A549 cells were treated with 1 μM lysosome sensor for 30 min and analysed under a two-photon confocal microscope. Scale bar, 10 μm. f The lysosomal pH values of A549 cells treated with PBS or HCQ for 12 h. g The A549/adr cells were stained with LAMP2, P-gp, and DAPI and analysed under a two-photon confocal microscope. Scale bar, 10 μm. h Verapamil-pre-treated (or not) A549/adr cells were treated with DOX (5 μg/ml, 2 h). The cells were stained with LAMP2 and analysed under a two-photon confocal microscope. Scale bar, 10 μm. i The viability of verapamil-pre-treated A549/adr cells treated with DOX for 24 h. j The viability of verapamil-pre-treated A549/adr cells treated with PBS, DOX or DOX combined with HCQ for 24 h. For all graphs, the error bars indicate the mean ± s.e.m., *P < 0.05; **P < 0.01; ***P < 0.001; ns, no significant difference. The data shown are representative of three independent experiments