Figure 2.

Inducible N1ICD overexpression in MCF-7 cells promotes a migratory behavior. (Aa-f) General view of the MCF-7 Tet-Off clones (B12, M5 and M20) cultured in the presence of DOXY. a-c, anti-myc staining reveals leaky myc-N1ICD expression; d-f, anti-myc and DAPI staining overlapping. (Ag-l) General view of these clones cultured in the absence of DOXY. g-i, anti-myc staining reveals N1ICD induction in these cells; j-l, anti-myc and DAPI staining. (B) Quantification of Hes1 promoter activity in MCF-7 uninduced and induced clones. Data are mean ± SEM of quadruplicates in three independent experiments (**P <0.005 determined by Student's t-test). (C) Western blot analysis of myc-N1ICD expression in MCF-7 control cells and MCF-7 clones after seven days of culture with or without DOXY. (D) Representative images of transmigrated cells in basal (-IGFI) and IGF-I supplemented (+IGF) cells. (a, b) control, (c, d) N1ICD-induced B12 and (e, f) M5 MCF-7 cells. (E) The relative migration index for each cell type is represented. Data are mean ± SEM of duplicates in three independent experiments (*P <0.05, **P <0.005 determined by Student's t test). DAPI, 4,6-Diamidino-2-phenylindol; DOXY, doxycycline; MCF-7, Michigan Cancer Foundation-7 breast cancer cell line; N1ICD, Notch one intracellular domain