Fig. 1: Wnt-less (Wls) deletion in osteoblast progenitors reduces c-Fos-induced OS.

a Experimental procedure to prevent Wnt secretion by deleting the Wls gene in osteoblast progenitors. Dox is removed at the onset of tumor formation (3 weeks of age, 1 week after Fos transgene expression is detected) and tumors are monitored at 5 and 15 weeks of age. b qPCR analysis of Wls, Wnt target genes and Fos mRNA species (endo, endogenous, Tg, transgene) in Wls^WT and Wls^ΔOB-OS tumor-bearing bones at 5 weeks of age. c–g Micro-CT analysis of Wls^WT and Wls^ΔOB-OS mice. Representative Micro-CT: 3D reconstructions (Top) and 2D virtual sections (bottom) of tumor-bearing bones. Red arrows point to OS (c). Tumor number per mouse (d), average tumor volume (e) and average tumor burden per mouse (f) at 5 and 15 weeks in Wls^WT-OS mice (n = 21) and Wls^ΔOB-OS mice (n = 15). g Volumetric follow-up over time for 41 Wls^WT-OS tumors and 23 Wls^ΔOB-OS tumors. h EdU incorporation by Wls^WT-OS (n = 13) and Wls^ΔOB-OS (n = 21) tumors at 15 weeks of age. The left panels are representative images of EdU-labeled cells 4 h after EdU injection (white arrows, nuclei counterstained with DAPI) while % EdU-labeled cells per tumor are plotted on the right. Bar graphs and plots represent or include mean ± SEM, respectively. *P < 0.05, **P < 0.01.