Fig. 6 |. Galectins demonstrate mechanical reciprocity and drive a mesenchymal phenotype.

a, Survival probability versus expression of Gal-1 (LGALS1). n = 214 patients with GBM (TCGA). P value calculated using two-sided logrank test. b, LGALS1 expression in proneural (Pro; n = 57 patients) and mesenchymal (Mes; n = 58 patients) GBM (TCGA). Mean ± s.e.m.; *P = 1.46 × 10^–19 by two-sided Mann–Whitney U-test. c, Correlation between LGALS1 and TNC from mesenchymal xenografts (n = 30 cDNA samples). Pearson’s correlation; log values of expression. d, WT and V737N proneural xenograft and syngeneic tumours were analysed for LGALS1 expression. Mean ± s.e.m. (n = 6 (syngeneic) and 5 (xenograft) mice per group). P = **0.009 and *0.032 by two-sided unpaired t-test. e, Xenografts were stained for Gal-1. Scale bar, 250 μm (n = 3 tissue sections). f, Proneural cells were plated on soft and stiff PA gels for LGALS1 expression. Mean ± s.e.m. (n = 3 independent experiments). g, Immunoblotting for Gal-1 and pT696-MYPT in proneural and mesenchymal cells on hydrogels (n = 2 independent experiments). h, RNA from control (Scr) or cells expressing Gal-1-silencing shRNA (shGal) was analysed. Mean ± s.e.m. (n = 9 and 2 independent experiments for TNC and vimentin, respectively). *P = 0.03 for TNC by two-sided paired t-test. i, Scr and shGal cells were analysed via immunoblotting (n = 3 independent experiments). j, Scr and shGal cells on soft hydrogels were imaged over 36 h (n = 12 cells per condition from 3 independent experiments). k, Velocity plot was derived from calculating the distance per time per frame, where n = 119 frames per condition averaged over 12 cells. Mean ± s.e.m.; ***P = 7.2 × 10^–20 by two-sided paired t-test. l, Scr and shGal on 2.7 kPa hydrogels were imaged using traction force microscopy. A representative traction map is shown (left); the colour bar represents increasing magnitude of stress with 0 (blue) denoting low stress and 16 (red) denoting high stress regions of the cell. The scatter plot (right) shows mean ± s.e.m. of n = 22 and 26 measurements for shGal and scr, respectively, over 3 independent experiments. **P = 0.004 by two-sided Mann–Whitney U-test. m, ECM stiffness of Scr, shGal and hyaluronidase-treated mesenchymal Scr (Scr+HAse) xenografts was analysed by AFM. Scatter plot represents 192 indentations per sample. Mean ± s.e.m. (n = 3 tumours analysed per group with four 90 × 90 μm regions mapped). ***F (2,573) = 144.3, P = 1.76 × 10^–51 verus Scr by one-way ANOVA and Bonferroni correction. n, Survival analysis of mice injected with Scr (n = 8 mice) and shGal-1 (n = 9 mice) GBM cells. P value calculated using two-sided logrank test. Source data: Supplementary Table 4; unprocessed blots: Supplementary Fig. 9.