Identification of ETS-1 target genes in human fibroblasts

The transcription factor Ets-1 plays several distinct critical roles in tumour development and progression by acting both in neoplastic cells and in the tumour stroma. Increased expression of Ets-1 in tumours is often associated with a worse prognosis. Stromal fibroblasts attribute an important part to the behaviour of malignant tumours. In this study we investigated the role of Ets-1 in the tumour stroma. It is well known that ets-1 expression in fibroblasts - one of the main components of the tumour stroma - can be induced by basic fibroblast growth factor (bFGF). We applied suppression subtractive hybridization (SSH) to identify genes that are differentially expressed between bFGF stimulated wild-type fibroblasts and fibroblasts with reduced Ets-1 expression. We selected clones up- or down-regulated in bFGF stimulated wild-type fibroblasts using SSH and functionally characterized them by reference to public databases using NCBI BLAST tools. Expression levels of genes corresponding to subtracted clones were analyzed using RT-PCR. Known genes were associated with diverse functions; novel Ets-1 regulated genes identified by SSH not only encoded components involved in matrix degradation (as cathepsin and PA 1-2) but also constituents of the extracellular matrix (ECM) including alpha-2-Type I collagen, TGF-beta induced protein, lumican and decorin. Our findings identify several potential novel target genes of Ets-1, and they provide potentially important insights into the role of Ets-1 in stromal fibroblasts for both remodelling and different functionalities of the ECM.