Fig. 4. Cell viability (A), DNA biosynthesis (B), collagen biosynthesis (C), total protein biosynthesis (D) and proline concentration (E) in wild type MCF-7 and MCF-7 transfected with prolidase cDNA expression vector (MCF-7 ^PL) untreated (Ctrl) and treated with glycyl-proline (GP), 2-methoxyestradiol (MOE) and MOE + GP. The mean values for 6 assays + S.D were calculated and submitted to statistical analysis using the ANOVA test, accepting P<0.001 as significant. Statistically significant differences are marked as: ^a vs. control wild-type MCF-7 cells, ^b vs. control MCF-7^PL cells, ^c wild-type MCF-7 cells vs. MCF-7^PL cells after treated by the same substances.