CHARACTERIZATION OF AN AFGF GENE-EXPRESSION VECTOR WITH THERAPEUTIC POTENTIAL

Background. Topical application of growth factors to wounds has proven to be suboptimal in achieving epithelial growth and accelerating heal ing. We propose transfection of fibroblasts with a gene for acidic fib roblast growth factor (aFGF) which will allow continuous, local delive ry of the growth factor to wounds, ulcerative lesions, or healing tiss ues. Methods. We utilized a pMEXneo vector containing the human aFGF g ene with a secretory signal sequence from the hst/KS3 gene to obtain c ontinuous secretion of therapeutic doses of aFGF. NIH 3T3 fibroblasts were transfected using a liposomal transfection reagent and grown in s elective media. Results. Dot blot hybridization with labeled complemen tary DNA probes revealed the presence of plasmid DNA in transfected bu t not wild type fibroblasts, Intracellular concentrations of aFGF rema ined low in transfected cells; however, the media contained high level s (32 +/- 7 nM) of aFGF as measured by ELISA. Concentrations of aFGF c apable of stimulating cell proliferation were maintained for several w eeks. Conclusions. The aFGF cDNA was transcribed and translated into a functional polypeptide that is secreted from NIH 3T3 cells at physiol ogically significant concentrations. Stable transfection with a eukary otic vector which induces secretion of aFGF at levels promoting cell g rowth holds promise for clinical application in wounds or healing tiss ue. Transfection could be achieved by topical or endoscopic injection of this type of vector. (C) 1998 Academic Press.