Fig. 5

Cholesterol depletion decreases neutral lipid cell area occupancy in cell lines impaired for spontaneous invasion. The 9 cell lines were plated on fibronectin-coated coverslips, serum-starved combined or not with 2mM mβCD (chol depletion) for 2 h, labeled at 37 °C with the BODIPY^493/503 specific to lipid droplets and then visualized by confocal microscopy. A Representative confocal images and insets to better evidence lipid droplet size and abundance (n = 2–3). B–E Quantification of total BODIPY^493/503 fluorescence area per cell (B, C) and lipid droplets area occupancy (D, E) of the 9 breast cancer cell lines in untreated conditions (B, D) or upon mβCD (C, E). Each data point represents the mean value of 1 image. Graphs are representative of 1 experiment among 2–3. F, G Linear correlations between the total BODIPY^493/503 fluorescence area and spontaneous invasion of cells treated with mβCD (F) and between Theta at cell ECM-free side combined with BODIPY^493/503 fluorescence area score and 2D aggressiveness score (G). 2D aggressiveness scores are from Additional file 1: Table S2. Theta at cell ECM-free side scores were based on chol labeling with Theta toxin (Fig. 4B): higher score was attributed to cells with higher Theta fluorescence intensity at the cell ECM-free side. BODIPY^493/503 fluorescence area scores were based on lipid droplet labeling with BODIPY^493/503 (B): higher score was attributed to cells with higher total BODIPY^493/503 fluorescence area. Each of these two later parameters were associated to a score ranging from 0 to 2, and scores were then added