Fig. 1: ERβ contributes to papillary thyroid CSCs.

a ESR1 and ESR2 mRNA expression in the spheroid cells and monolayer cells of TPC-1 cells and K-1 cells were analyzed by RT-qPCR. Data were shown as means ± SD (n = 3, ***P < 0.001). b A panel of core pluripotency factors (NANOG, SOX2, and POU5F1) were measured between spheroid cells and monolayer cells from both TPC-1 cells and K-1 cells. Data were shown as means ± SD (n = 3, *P < 0.05, **P < 0.01 and ***P < 0.001). c PTC tissue specimens were subjected to IHC staining by ERβ and NANOG antibodies. Representative images were presented. Scale bar, 100 or 20 μm. d The correlation between the ERβ and NANOG expression in PTC tissues from 41 patients. ***P < 0.001. e The protein levels of ERβ and stemness-related factors NANOG and OCT4 were measured in siNC and siERβ K-1 cells. β-Actin acted as the loading control. f The proportions of ALDH⁺ cells were compared between siNC and siERβ K-1 cells. g Sphere formation ability was performed in ERβ depletion K-1 cells. Representative images were presented (up), the scale bar represents 50 μm. The numbers and size of spheres were counted after culture for 10 days (down). Data were shown as means ± SD (n = 3, **P < 0.01 and ***P < 0.001). h BALB/c nude male mice (n = 5) were subcutaneously inoculated with equal number of single cells (1 × 10⁶ cells). The tumors were harvested at day 23 after injection (upper panel). Tumor volumes were monitored as described (lower panel)