IGFBP-3 down-regulates bFGF transcription. (A) Western blot analysis of IGFBP-3 and bFGF expression in NSCLC and HNSCC cells 2 days after infection with Ad-EV or Ad-BP-3. (B) Reduced bFGF levels in the CM from rBP-3–treated UMSCC38 cells. N.S. indicates nonspecific bands. (C) Semiquantitative RT-PCR analysis of bFGF expression in H460 cells infected with Ad-EV or Ad-BP-3 (left) or transfected with scrambled (Con) or IGFBP-3 (BP-3) siRNA (right). (D) Luciferase assay to determine the effect of IGFBP-3 on bFGF promoter activity in H460 cells transiently transfected with bFGF-Luc in association with Ad-BP-3 or Ad-EV infection at the indicated doses (left), rBP-3 treatment (middle), or scrambled (Con) or IGFBP-3 (BP-3) siRNA cotransfection (right). The results represent the means (bars, SDs) of triplicate results. *P < .05; **P < .01; ***P < .001.