THE ETS-1 AND ETS-2 TRANSCRIPTION FACTORS ACTIVATE THE PROMOTERS FOR INVASION-ASSOCIATED UROKINASE AND COLLAGENASE GENES IN RESPONSE TO EPIDERMAL GROWTH-FACTOR

Urokinase plasminogen activator (uPA) has been associated with invasio n and metastasis in breast cancer. The expression of uPA and 92 kDa ty pe IV collagenase (gelatinase B/MMP-9) is regulated by growth factors, receptor-type tyrosine kinases and cytoplasmic oncoproteins, Here, we have identified transcriptional requirements for the induct-ion of uP A and 92 kDa type IV collagenase by epidermal growth factor (EGF), EGF stimulates the motile and invasive activities specifically in the Erb B-2-overexpressing SK-BR-3 cells, Expression of extracellular matrix-d egrading proteases including type 1 collagenase/MMP-1, 92 kDa type IV collagenase/MMP-9, uPA and uPA receptor were induced. EGF also transie ntly stimulated expression of the transcription factors Ets-1 and Ets- 2, Reporter transfection assays revealed the activation of uPA and MMP -9 collagenase promoters by EGF and the requirement of each of the com posite Ets and AP-I transcription factor binding sites for an EGF resp onse. Most notably, transfections with the Ets-1 and Ets-2 expression vectors potentiated uPA and MMP-9 promoter activation in response to E GF, Mutation of the threonine 75 residue of chicken Ets-2 conserved in the pointed group of the Ets family proteins abrogated the ability of Ets-2 to collaborate with EGF, Ets-1 and Ets-2 were highly expressed in invasive breast tumor cell lines. Our results suggest that Ets-1 an d Ets-2 provide the link connecting EGF stimuli with activation of uPA and 92 kDa type IV collagenase promoters and may contribute to invasi on phenotypes.