Figure 1.

Cell growth and tumorigenicity of Tet-inducible MCF7 FEZ1 transfectants. (A) Immunoblot analysis with anti-Fez1 antibody of MCF7 FEZ1 transfectants. Four Tet-inducible MCF7 FEZ1 transfectants (clones 15, 18, 54, and 118) were cultured in Tet-free 5%-serum medium to induce Fez1 expression. Proteins were extracted and analyzed before (lanes 1, 3, 5, 7, and 9) and after (lanes 4, 6, 8, and 10) Fez1 induction. Lanes 1 and 2, control vector transfectants. (B) In vitro cell-growth analysis. After Fez1 induction, four clones were seeded in 10, 5, 2.5, 1, or 0.5% serum medium without Tet. Cell growth of Tet-inducible MCF7 FEZ1 transfectants were analyzed by MTS assay. Data from transfectants were divided by data from control vector transfectants for the ratio. (C) Tumorigenicity of MCF7 FEZ1 transfectants. Cells of four MCF7 FEZ1 transfectants precultured in Tet-free medium for 72 hr [5 × 10⁶ (I) or 2 × 10⁷ (II)] were inoculated into four nude mice for each. ●, clone 15; ■, clone 18; □, clone 54; ⋄, clone 118; ○, control vector transfectant.