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Matrix metalloproteinase-9 (MMP9) plays a critical role in tumor invasion, metastasis angiogenesis, inflammation, and would healing. Here, we investigate the effect of fibroblast growth factors-1 on the expression of MMP-9 in ENU1564, a carcinogen-induced rat mammary adenocarcinoma cell line. Gelatin zymography, and RT-PCR demonstrate that FGF-1 dose dependently increased MMP-9 mRNA level and gelatinolytic activity in conditioned medium. Also, FGF-1 treatment of cancer cells activated phosphorylation of Akt, Erk 1/2, and SPK/JNK. Pretreatment of cells with LY294002, a PI3K inhibitor significantly inhibited FGF-1-dependent activation of MMP-9. Also, pretreatment with SP600125, and JNK inhibitor, and with PD98059, and ERK 1/2 inhibitor, strongly inhibited FGF-1-dependent MMP-9 expression. FGF-1-triggered nuclear translocation of NF-kB p65, c-jun, and enhanced degradation of cytoplasmic IkB-α. Electrophoretic mobility shift assay confirmed increased DNA binding of NF-kB, and AP-1 to the MMP-9 promoter in FGF-1 treated cells. The specificity of DNA binding complex was determined by supershift analysis. To define the transcriptional regulation of MMP-9 by FGF-1 we performed promoter-reporter assays. In the previous studies a number of transcription factor binding sites have been characterized in the upstream region of the MMP-9 gene, including those for AP-1, and NF-kB. Our results indicate that mutation of either response element prevented MMP-9 promoter activation by FGF-1. Taken together, these results demonstrated that FGF-1-upregulates MMP-9 expression by activation of a dual signalling pathway, Akt and MAPK, and contribute to cancer progression.

98th AACR Annual Meeting-- Apr 14-18, 2007; Los Angeles, CA