IGFBP-3 down-regulates bFGF expression promoter activity by regulating Egr-1 transcription. (A) Western blot (top) and semiquantitative RT-PCR (bottom) analyses of IGFBP-3's effect on Egr-1 and Sp-1 protein and mRNA expression in H460 cells that had been infected with Ad-BP-3 or Ad-EV for 2 days. (B) Luciferase assay to determine Egr-1's effect on bFGF expression. H460 cells transiently transfected with bFGF-Luc and pEgr-1, pBP-3, or both; *P < .05, **P < .01. (C-D) RT-PCR analysis of PDGFa and PDGFb mRNA expression in H460 cells (C) and Western blot analysis of PDGF protein expression in H1299 and A549 cells (D) after infection with Ad-EV or Ad-BP-3 or treatment with rBP-3. (E) Immunohistochemical analysis of Egr-1, bFGF, and PDGF expression in H1299 xenografts 10 days after injection with Ad-EV or Ad-BP-3.