Figure 4.

The exogenous expression of Bmi-1 promotes the motility and invasiveness of immortalized HMECs. (A) The endogenous expression of Bmi-1 was detected in breast cancer cells and immortalized HMECs by immunoblotting. (B) The overexpression of Bmi-1 in transfected immortalized HMECs was confirmed by RT-PCR and immunoblotting. GAPDH and anti-α-Tubulin were used as loading controls, respectively. (C) Bmi-1 did not affect the proliferation of immortalized HMECs. (D) The invasive properties induced by EGF and Insuline were analyzed by an invasion assay using Matrigel-coated Boyden chambers and scored under a light microscope (200X). (E) A wound was produced and monitored at 0, 12, and 24 hours as the cells moved and filled the damaged area in serum-free medium (200X). The data were plotted as the average number of cells per field of view (***P < 0.001).