Figure 1. GATA1 regulates VEGF expression in breast cancer cells.

(A) Schematic illustration of screening for transcription factors that regulate VEGF-Luc reporter activity in ZR75-1 breast cancer cells. (B) Luciferase reporter assays in ZR75-1 breast cancer cells cotransfected with the VEGF-Luc reporter and the indicated transcription factors from (A). All values shown are expressed as the mean ± SD obtained from two independent experiments. **P < 0.01 versus empty vector. (C) Luciferase reporter assays in ZR75-1, MCF-7 and MDA-MB-231 breast cancer cells cotransfected with VEGF-Luc and GATA1 shRNAs or control shRNA. Representative Western blot shows the expression of GATA1. GAPDH was used as a loading control. (D) Real-time RT-PCR analyses of the expression of VEGF₁₂₁ and VEGF₁₆₅, two major VEGF isoforms, in ZR75-1, MCF-7, and MDA-MB-231 cells stably infected with lentivirus carrying GATA1 shRNA or control shRNA. Representative Western blot indicates the expression of GATA1. (E) VEGF concentration in cell supernatants by ELISA and VEGF protein expression by Western blot from ZR75-1, MCF7 and MDA-MB-231 cells stably infected as in (D). Data shown are mean ± SD of triplicate measurements that have been repeated 3 times with similar results (C–E). *P < 0.05, **P < 0.01 versus control shRNA.