Differential roles of fibroblast growth factor receptors (FGFR) 1, 2 and 3 in the regulation of S115 breast cancer cell growth.

Fibroblast growth factors (FGFs) regulate the growth and progression of breast cancer. FGF signaling is transduced through FGF receptors 1-4, which have oncogenic or anti-oncogenic roles depending on the ligand and the cellular context. Our aim was to clarify the roles of FGFR1-3 in breast cancer cell growth in vitro and in vivo.

Androgen and fibroblast growth factor 8 (FGF8) downregulation of thrombospondin 1 (TSP1) in mouse breast cancer cells.

In the search for androgen target genes responsible for malignant growth in S115 mouse mammary tumor cells we found that thrombospondin 1 (TSP1) expression was strongly downregulated by testosterone (Te). Experiments with cycloheximide suggested that Te repression of TSP1 was dependent on de novo protein synthesis. TSP1 repression by Te was preceded by the induction of fibroblast growth factor 8 (FGF8) expression.