Fig. 6
SFX induces fusion of MVE with lysosomes in breast cancer cells. a TEM analysis of SFX-treated MDA-MB231 cells. Red arrows indicated unusual structures in SFX-treated MDA-MB231 and MCF7, and white arrows indicated MVEs in control cells. Scale bar, 5 μm. b Top, Images of lysosome and autolysosome structures observed in SFX-treated MDA-MB231 cells. Bottom left, the numbers of distributed lysosome and autolysosome structures were counted. n = 20. Bottom right, LAMP-1 protein expression was upregulated in SFX-treated MDA-MB231 cells. n = 3. c Confocal image of CD63-GFP (+)-MDA-MB231 in the presence or absence of SFX. Red, lysotracker. Green, CD63-GFP. Scale bar, 2 μm. d Measurement of Lysotracker (red) intensity in rapamycin-treated (positive control) or SFX-treated MDA-MB231 cells. Lysotracker intensity measurement >170 cells per group. e Left, Image of MDA-MB231 treated by 100 μM SFX. Green, CellLight-Lysosome-GFP (GFP-LAMP1). Red, CellLight-late endosome/MVE-RFP (RFP-RAB7). Scale bar, 2 μm. Right, Quantitative colocalization rates of lysosomes and MVE in SFX-treated MDA-MB231. Colocalization puncta count >60 cells per group using ImageJ program. Bafilomycin A1 (BafA1) was used as a negative control. Experiments were performed with 95% confluent cells. Significance was determined using an unpaired two-tailed Student’s t-test. ***p < 0.001, **p < 0.005 and *p < 0.05. Error bar, SD. Source data (b, d, e) are provided as a Source Data file
