Figure 4

The potential function link between COP1 and ETV1 in MDA-MB-231 cells. A, Expression of ETV1 and COP1 in breast cancer cell lines. B, MDA-MB-231 cells were infected with recombinant COP1 lentivirus (LV-COP1) or lentivirus with empty vector (LV-NC). LV-COP1 infected cells were further transfected with siCOP1, a non-specific RNA (siNC) as a negative control. Western blotting showed inverse relationship between COP1 and ETV1 expression. C, LVCOP1 infected MDA-MB-231 cells were treated with DMSO or 2 μM Bortezomib for 2 h and then subjected to western blotting. D, MDA-MB-231 cells were transfected with siETV1 or siNC, or were infected with LV-NC or LV-COP1 for 72 h. Normal MDA-MB-231 cells were considered to be control group. CCK8 assay showed that siETV1 significantly decreased the cell proliferation while overexpression of COP1 did not influence the cell proliferation of MDA-MB-231. E-G, MDA-MB-231 cells were treated as showed in the figures and cultured for 48 h. Cell migration and invasion assays were performed using cell culture inserts with PET membrane and BD matrigel invasion chamber, respectively. Results indicated that suppressing ETV1 or up-regulating COP1 decreased the migration (E) and invasion (F, G) ability of MDA-MB-231 cells. Turnover ETV1 expression in LV-COP1 infected cells partly rescued the migration and invasion function of cells. Scale bar, 100 μm. (Students t tests, ***P < 0.001 versus MDA-MB-231 control group; #P < 0.05, ##P < 0.01, versus LV-COP1 group).