Figure 1. c-Myb inhibits lung metastasis of BC cells.

(a) Number of metastatic foci in lungs of tumor-bearing BALB/c mice 28 days after m.f.p. injection of 4T1 cells: mock or Myb-overexpressing clones MM5 and MM8B (2 independent experiments). Representative images of lungs fixed in Bouin’s solution. (b-c) Metastasis of MDA-MB-231 cells upon m.f.p. injection into NSG mice and terminated at day 42, using MDA-MB-231 cells: transfected with empty vector (mock), expressing human MYB (MYB^high), transfected with control gRNA (Scr); and deficient in MYB expression (MYB KO). (b) Quantification of lung metastasis with representative H&E stained lung sections; scale bar = 50μm. (c) Quantification of bone metastasis incidence and amounts with representative H&E stained bone sections; scale bar = 100μm. (d) Lung seeding of parental = wt, and lung3 cells. Number of colonies formed by 4T1 cells lodged in lungs 24 hours p.i (n=3). (e) Quantification of lung metastatic foci from BALB/c mice bearing 4T1 wt and lung3 tumors 28 days after m.f.p. injection (2 independent experiments). (f) Immunoblot analysis of c-Myb expression in parental (wt), and lung3 subline of 4T1 cells. Expression levels of Myb mRNA in the lung3 subline analyzed by qPCR and normalized to Gapdh, showed as relative values to parental cells (n=5). *; p<0.05; **; p<0.01; ***; p<0.001.