Fig. 6: ELKIN1 modulates the microgravity-dependent inhibition of cancer cell invasion from organotypic spheroids.

Example images of organotypic spheroids formed from WT-3B6 (A–E) or E1KO-3C6 (F–J) cells embedded in a collagen I gel. A reference image of a spheroid at Time0 is presented for each cell type in A and F, Hoechst labelled nuclei are presented in blue and phalloidin staining of actin to label cells in magenta. The example images suggest that the application of microgravity to WT cells reduces spheroids size the amount of cell invasion after 24 (B, D) and 48 h (C, E). In contrast, the invasion of the collagen gel by cells dissociating from E1KO spheroids appear similar in both 1 g controls and microgravity treated samples (F–J). The number of cells dissociated were quantified after 24 h treatment (K) and 48 h treatment (L). Data are presented as normalised against the respective 1 g controls. K After 24 h of simulated microgravity, significantly fewer cells had dissociated from the WT spheroids, compared to 1 g controls, however no significant difference was noted for E1KO spheroids (Kruskal-Wallis with uncorrected Dunn’s test; WT-3B6 control (24 h); n = 11; WT-3B6 microgravity (24 h); n = 12 ***p = 0.0003; E1KO-3C6 control (24 h); n = 11; E1KO-3C6 microgravity (24 h); n = 12 ns p = 0.519). L After 48 h simulated microgravity, fewer cells had dissociated from the treated WT spheroids and the treated E1KO spheroids, compared to the respective 1 g controls (Kruskal-Wallis with uncorrected Dunn’s test; WT-3B6 control (48 h); n = 10; WT-3B6 microgravity (48 h); n = 9 *p < 0.036; E1KO-3C6 control (48 h); n = 11; E1KO-3C6 microgravity (48 h); n = 9 *p = 0.027).