Fig. 1

Cholesterol depletion decreases invasion of the 6 invasive cell lines in 2D. Nine cell lines were either serum-starved combined or not with 2 mM mβCD (chol depletion) for 2 h (A, C) or treated with 10 µM GM6001 (MMP inhibition) during the whole experiment (B, D) and then tested for oriented invasion (A, B) and gelatin degradation (C, D, I). A, B Quantification of oriented cell invasion in Matrigel-coated Transwell toward 10% serum for 12 h upon mβCD or GM6001 (n = 3–12 Transwell from 2–5 independent experiments and n = 3–6 Transwell from 1–3 independent experiments, respectively). The oriented invasion index was calculated by subtracting the number of spontaneously invading cells toward 0% serum. ni, non-invasive. For determination of invasion capacity, see Fig. S3A. C, D Quantification of gelatin degradation potential of cell lines serum-starved combined or not with mβCD for 2 h (C) then stimulated for 6–12 h with serum-containing medium or serum-starved for 2 h and then incubated in GM6001-supplemented medium for 6–12 h (D; 188–669 cells from n = 22–78 images from 2–5 independent experiments and 284–699 cells from n = 12–62 images from 1–4 independent experiments, respectively). Wilcoxon signed-rank test (A–D). E–H Relations between the oriented invasion of 6 cell lines treated with mβCD and number of invading cells (E), 2D aggressiveness score (F) or oriented invasion upon GM6001 (G), or between gelatin degradation potential upon both drugs (H). I Representative confocal images of gelatin degradation areas (black areas) of the 9 cell lines (immuno) labeled with anti-Cortactin, Phalloidin (F-actin) and Hoechst (nuclei). Orange, yellow and blue arrowheads, cortactin+ structures, cortactin/F-actin+ structures and cortactin/F-actin+ structures associated with degradation areas, respectively (n = 1–5). For enlarged views of the 3 degrading cell lines, please refer to Additional file 1: Fig. S5B