Fig. 1.

Tgif1 supports the osteoblast-breast cancer cell interaction in vitro.a Migration of 4T1-GFP and b of MDA-MB-231 breast cancer cells towards control (Ctrl) medium or medium conditioned by osteoblasts (ObCM). c Representative images of MDA-MB-231 cells immobilized on transwell inserts after migration. Scale bar indicates 20 μm. d Tgif1 mRNA expression in osteoblasts 1 and 2 h after stimulation with medium conditioned by 4T1 breast cancer cells (CCM). e Immunoblot demonstrating the protein abundance of Tgif1, phosphorylated ERK1/2 (p-ERK1/2), and total ERK1/2 in MC3T3-E1 osteoblasts after stimulation with CCM for 1 and 2 h. Immunoblot for actin was used as a loading control. f MC3T3-E1 cells were incubated with vehicle (DMSO) or with an inhibitor of ERK1/2 signaling and stimulated with CCM for 1 and 2 h. Immunoblot to demonstrate the abundance of Tgif1, p-ERK1/2, total ERK1/2, and actin. g Transwell assay of MDA-MB-231 breast cancer cell migration towards Ctrl medium or medium conditioned by osteoblasts that were isolated from mice bearing a germ line deletion of Tgif1 (Tgif1^−/−) or from Tgif1^+/+ control littermates. N = 3–5 with experimental replicates. Data are presented as mean ± SEM. Two-tailed Student’s t test was used to compare two groups (a, b), and ANOVA followed by Tukey’s post hoc analysis was used to compare more than two groups (d, g); *p < 0.05, **p < 0.001, ***p < 0.001, ****p < 0.0001