Fig. 7: Involvement of the TGFβ/Nur77/ID1 axis in colon cancer stemness and metastasis.

a, b LS174T cells transfected with the indicated siRNAs were cultured for 7 days. Cell spheres were observed by microscope. Representative images were shown, and sphere numbers and diameters were counted and measured (a). Scale bars, 100 μm. The expression of stemness markers was determined by qRT-PCR (b). si-ctr control siRNA, si-ID1 ID1 siRNA, si-Nur77 Nur77 siRNA, si-Smurf2 Smurf2 siRNA. Two-way ANOVA followed by Tukey’s multiple comparisons test was used for statistical analysis, and data are presented as means ± SD. (a, top graph, n = 3 biologically independent samples; a, bottom graph, n = 37, 60, 9, 11, 35, 33, 7, 9, 32, 25, 6, 14, respectively; b, n = 5 biologically independent samples). c–f SW620/sh-ctr and SW620/sh-Nur77 cells were injected into spleens of nude mice. Mice were reared for 28 days and then sacrificed for analysis of tumor formation (c), tumor-bearing spleen and liver weight and coefficient (c), hematoxylin and eosin staining of tumor tissues (d), protein interactions and expressions in spleen tumors (e), and Smad3 phosphorylation status in spleen tumors comparing to in vitro SW620 cells treated with TGFβ (f). The white areas indicate tumors formed in spleens and livers (c). Tumor tissues are separated from normal tissues by dotted lines (d). S spleen, L liver, T tumor. Scale bars, 100 μm. Two-tailed unpaired Student’s t test was used for statistical analysis, and data are presented as means ± SD (n = 4 mice per group). Data represent at least two independent experiments. Source data are provided as Source Data file.