Fig. 4

Sialylation and lipid accumulation in ketomimetic media contribute to DOX chemoprotection. A Confocal fluorescence imaging of MDA-MB-231 cells obtained after DOX internalization with and without sialidase treatment in the respective nutrient media: high glucose (HG), low glucose (LG) and HBLG (hydroxybutyrate containing low glucose). Red: DOX; scale bar: 100 µm. B Confocal fluorescence imaging of MCF-7 cells obtained after DOX internalization with and without sialidase treatment in the respective nutrient media. Red: DOX; scale bar: 100 µm. C, D Representative confocal microscopy images of MDA-MB-231 (C) and MCF-7 (D) cells obtained using BODIPY staining for detection of lipid droplets in the respective nutrient media. DRAQ5 was used as a nuclear counterstain. Green: BODIPY 505, Blue: DRAQ5; scale bar: 100 µm. Fluorescence quantification is shown on the right side of each panel. All images were collected at identical conditions and are displayed with the same LUT. The DOX or BODIPY signal per cell was quantified as I_DOX-I_blank/cell # or I_Bodipy-I_blank/cell #, respectively and fold changes were computed relative to no sialidase and HG as controls, respectively. For each cell type, images from at least three separate experiments (N = 3) were used with 10–15 different FOVs collected for each experiment. For all graphs, symbols represent means and error bars denote SEM. Statistical analysis for significance was performed using a two-tailed unpaired t-test in GraphPad Prism where **, *** indicate p < 0.01, and p < 0.001, respectively