Fig. 7

Smyca serves as a therapeutic target to prevent metastasis and chemoresistance. (A, B) Experimental metastasis assay for MDA-MB-231 cells stably expressing Smyca shRNAs (A) or Smyca (B). Representative images of the bioluminescence analysis at 8 weeks (A) or 7 weeks (B) after injection and the kinetics of metastasis at indicated time points are shown on the top left and right panels, respectively. The lung images at 8 weeks (A) and 7 weeks (B) after injection are shown on the bottom. Bar, 2 mm. (C) Cell viability assay of MDA-MB-231 cells stably expressing Smyca shRNAs and treated with Dox or cisplatin at indicated doses. (D) Nude mice orthotopically implanted with MDA-MB-231 cells stably expressing control or Smyca shRNAs and treated with Dox or DMSO as indicated (top left panel). Tumor volumes were measured at indicated days and plotted on the right. Tumors were surgically removed at the killing day and their sizes are shown on the bottom left panel. (E) NOD/SCID mice orthotopically implanted with LM6 cells were injected with NPs and/or Dox as indicated (top left panel). Tumor volumes at indicated days are shown on the right. Tumors were surgically removed at the killing day and their sizes are shown on the bottom left panel. (F) NOD/SCID mice orthotopically implanted with LM6 cells were injected with NPs as indicated (top left panel). Representative images of the bioluminescence analysis at 6 weeks after transplantation and the kinetics of metastasis at indicated time points are shown on the top right and bottom left panels, respectively. The lung images at 6 weeks after transplantation are shown on the bottom right. Bar, 2 mm. Data in (A), (B), (C), (D), (E), and (F) are mean ± SD, n = 5 (A), n = 4 (B, D, E, F), or n = 3 (C). P values are determined by one-way (A, C) or two-way (D, E) ANOVA with Tukey’s post hoc test or unpaired t test (B, F), *P < 0.05, **P < 0.01, ***P < 0.001; ns, not significant. (G) Schematic presentation of the roles of Smyca in coactivating TGF-β/Smad and Myc pathways to promote tumor progression