Figure 6. Gd@C₈₂(OH)₂₂ nanoparticles effectively eliminate CSCs by the abrogation of TGF-β under normoxia.

(a) After treated with PBS, Gd@C₈₂(OH)₂₂, C₆₀(OH)₂₂ or GdCl₃ for 21 days and 20 ng ml⁻¹ TGF-β for 24 h, MDA-MB-231 tumourspheres were photographed and quantitated (b) (mean±s.e.m., n=3 each) (scale bar, 100 μm). To tumourspheres of 70–150 μm, **P<0.01; to tumourspheres of >150 μm, ^##P<0.01 (two-way ANOVA, Bonferroni’s post-hoc test). (c) mRNA levels of CSC markers were analysed by qPCR (mean±s.e.m., n=3 each). *P<0.05 (two-way ANOVA, Bonferroni’s post-hoc test). (d) Tumour injection of MDA-MB-231 cells by limiting dilutions. Different numbers (5 × 10⁶, 5 × 10⁵, 5 × 10⁴, 5 × 10³, 5 × 10²) of MDA-MB-231 cells were injected into the right back flanks of the mice s.c. Mice were monitored and treated daily. (e) Tumoursphere formation of cells isolated from tumour tissues (mean±s.e.m., n=3 each). **P<0.01 (one-way ANOVA, Tukey’s post-hoc test). (f) The tumourspheres were counted.