Inhibition of the fibroblast growth factor receptor 1 (FGFR-1) gene in human melanocytes and malignant melanomas leads to inhibition of proliferation and signs indicative of differentiation.

Fibroblast growth factor receptor (FGFR-1) is expressed as a single 3.5-kb mRNA transcript in normal human melanocytes and in malignant melanomas as determined upon Northern hybridization to a cDNA clone encoding the membrane-spanning form of the human FGFR-1. Polyclonal antisera directed against the chicken FGFR recognized a 145-kDa protein in primary and metastatic melanomas. Antisense oligodeoxynucleotides targeted against the translation start site and a splice donor-acceptor site of human FGFR-1, in addition to inhibiting the proliferation of normal human melanocytes and malignant melanomas, caused extensive dendrite formation and severe disruption of cell-cell contact--morphological changes that were not observed upon inhibition of the genes encoding basic fibroblast growth factor (bFGF) and retinoic acid-alpha receptor. Thus, unlike in the case of the ligand bFGF, expression of the FGFR-1 may represent a requisite to prevent human melanocytes and malignant melanomas from undergoing (terminal) differentiation.