Fig. 3: Controlling cancer-cell stiffness to modulate T-cell force-mediated cytotoxicity through membrane cholesterol depletion.

a Illustrations of mechanical immuno-suppression induced by the softened cancer cells and mechanical immuno-activation induced by the stiffened cancer cells resulting from membrane cholesterol depletion. b Cholesterol levels in different cells. n = 3 biologically independent samples per group, repeated three times. c Cholesterol levels in 4T1 tumor tissues or the adjacent muscle tissues. n = 3 biologically independent samples per group, repeated three times. d, e Relative intracellular and plasma membrane levels of cholesterol in 4T1 cancer cells treated with PBS, MeβCD, NPNs, or RDPNs in vivo (d) and in vitro (e). n = 3 biologically independent samples per group, repeated three times. f, g The Filipin III staining of 4T1 tumor cells after different treatments. Experiments were performed three times with similar results. Scale bar, 100 nm. h Relative cortical stiffness of 4T1 cancer cells treated with different treatments. n = 6 biologically independent samples per group, repeated three times. i The schematic diagram of perforin forming pores in native cancer cells or stiffness cancer cells. j Viability of pre-treated 4T1 cancer cells after incubation with perforin at indicated concentrations at 37 °C for 20 min. n = 3 biologically independent samples per group, repeated three times. k Lysis percentage of 4T1 cancer cells pre-treated with activated CD8⁺ T cells at an E: T ratio of 10:1 for 5 h. n = 4 biologically independent samples per group. Data were expressed as means ± SD. G1: PBS, G2: MeβCD, G3: NPNs, G4: RDPNs. One-way ANOVA with Tukey’s post hoc test (b, d, e, h, k) or Two-tailed Student’s t-test (c). *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001.