Expression of fibroblast growth factor (FGF)-10 in human colorectal adenocarcinoma cells

Fibroblast growth factor (FGF) -10 (keratinocyte growth factor 2, KGF 2) is a new member of the FGF family that is mainly synthesized by mesenchymal cells and acts predominantly on epithelial cells in a paracrine manner. Its actions are dependent on its binding to the iiib isoform of the cell-surface FGF receptor 2 (FGFR2 iiib). FGF-10 is known to play an important role in fetal limb and lung development, skin wound healing and prostatic epithelial cell growth. In the present study, the expression of FGF-10 and FGFR2 iiib in five cultured human colorectal adenocarcinoma cell lines (COLO 205, DLD-1, HCT-15, SW 480 and WiDr) and the localization of FGF-10 messenger RNA (mRNA) and its protein in human colorectal cancer tissues from 10 patients were determined. All five colorectal cancer cell lines expressed FGF-10 mRNA and its protein. FGFR2 iiib mRNAs were expressed in these cells and the recombinant FGF-10 (1 ng/ml) increased the growth rate of COLO 205 cells. To determine the localization of FGF-10 protein and its mRNA in normal and cancerous human colorectal tissues, immunohistochemistry and in situ hybridization were performed. In normal colorectal tissues, FGF-10 and its mRNA were not detected. In contrast, moderate immunoreactivity was present in cancer cells in 5 of 10 colorectal cancer cases and mild immunoreactivity was recognized in adjacent fibroblasts. By using in situ hybridization, FGF-10 mRNA was observed in colorectal cancer cells and fibroblasts adjacent to cancer cells. These findings indicate that FGF-10 and its receptor, FGFR2 iiib expression in colorectal adenocarcinoma cells and FGF-10 may contribute to the growth of cells of this type.