Induction of the angiogenic modulator fibroblast growth factor-binding protein by epidermal growth factor is mediated through both MEK/ERK and p38 signal transduction pathways.
Fibroblast growth factor-binding protein (FGF-BP) is a secreted protein that binds and activates fibroblast growth factors (FGF-1 and FGF-2) and induces angiogenesis in some human cancers. FGF-BP is expressed at high levels in squamous cell carcinoma (SCC) cell lines and tumor samples and has been shown to be rate-limiting for the growth of SCC tumors in vivo. In this study, we examine the regulation of FGF-BP by epidermal growth factor (EGF) and the signal transduction mechanisms that mediate this effect. We found that EGF treatment of the ME-180 SCC cell line caused a rapid induction of FGF-BP gene expression. This induction was mediated transcriptionally through the AP-1 (c-Fos/JunD) and CCAAT/enhancer-binding protein elements as well as through an E-box repressor site in the proximal regulatory region of the FGF-BP promoter. Pharmacological inhibition of protein kinase C and mitogen-activated protein kinase/extracellular signal-regulated kinase kinase 1/2 (MEK1/2) completely blocked EGF induction of FGF-BP mRNA, whereas inhibition of phosphatidylinositol 3-kinase had no effect. Additionally, both EGF- and anisomycin-induced FGF-BP mRNA was abrogated by inhibition of p38 mitogen-activated protein kinase, demonstrating a role for p38 in the regulation of FGF-BP. Co-transfection of the FGF-BP promoter with dominant negative forms of MEK2, extracellular signal-regulated kinase 2, and p38 significantly decreased the level of EGF induction, whereas expression of a dominant negative c-Jun N-terminal kinase mutant or expression of c-Jun N-terminal kinase inhibitory protein had no effect. Similarly, activation of the p38 pathway by overexpression of wild-type p38 or MKK6 enhanced FGF-BP transcription. These results demonstrate that EGF induction of FGF-BP occurs selectively through dual activation of the stress-activated p38 and the MEK/extracellular signal-regulated kinase mitogen-activated protein kinase pathways, which ultimately leads to activation of the promoter through AP-1 and CCAAT/enhancer-binding protein sites.
Harris
V K
VK
Department of Oncology, Vincent T. Lombardi Cancer Center, Georgetown University, Washington, D.C. 20007, USA.
Coticchia
C M
CM
Kagan
B L
BL
Ahmad
S
S
Wellstein
A
A
Riegel
A T
AT
D022762:CCAAT-Enhancer-Binding Proteins; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000502:physiology*; D002352:Carrier Proteins / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000378:metabolism; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D005260:Female; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D048031:JNK Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D019950:Mitogen-Activated Protein Kinase 1 / Q000502:physiology*; D048052:Mitogen-Activated Protein Kinase 3; D020929:Mitogen-Activated Protein Kinase Kinases / Q000502:physiology; D020928:Mitogen-Activated Protein Kinases / Q000502:physiology*; D009687:Nuclear Proteins / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011493:Protein Kinase C / Q000502:physiology; D020218:Response Elements; D015398:Signal Transduction; D016329:Sp1 Transcription Factor / Q000378:metabolism; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014407:Tumor Cells, Cultured; D048051:p38 Mitogen-Activated Protein Kinases
D022762:CCAAT-Enhancer-Binding Proteins; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D036341:Intercellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D016329:Sp1 Transcription Factor; D018808:Transcription Factor AP-1; C070699:FGFBP1 protein, human; D004815:Epidermal Growth Factor; D011493:Protein Kinase C; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D020929:Mitogen-Activated Protein Kinase Kinases