Sequence-specific antiproliferative effects of antisense and end-capping-modified antisense oligodeoxynucleotides targeted against the 5'-terminus of basic-fibroblast-growth-factor mRNA in coronary smooth muscle cells.

Basic fibroblast growth factor (bFGF), a potent mitogen for arterial smooth muscle cells, has been shown to play a fundamental role in the pathogenesis of arteriosclerosis and restenosis by stimulating the proliferation of vascular smooth muscle cells. We found that partially phosphorothioate-modified 15-residue antisense oligodeoxynucleotides complementary to bFGF mRNA at 0.1-2.0 microM block growth and division of cultured human and bovine coronary smooth muscle cells in a dose-dependent manner. The effect is sequence specific at low (0.1-0.5 microM) nontoxic concentrations. It is associated with inhibition of expression of pericellular and intracellular bFGF, with a decreased de novo synthesis of bFGF and is partly reversible by the addition of exogenous (recombinant) bFGF. The antisense effect lasts 48-72 h and diminishes thereafter. If the antisense oligodeoxynucleotide medium is replaced by an oligonucleotide-free medium after 24 h, the [3H]thymidine incorporation rate returns to control levels. Under the same conditions, the corresponding sense oligodeoxynucleotide exerts negligible nonspecific inhibitory actions. The antiproliferative potency of the 15-residue antisense oligodeoxynucleotide is markedly enhanced by adding 3-4 nonbase-pairing guanosine residues at the 5'- and 3'-termini of the 15-residue antisense oligonucleotide. The data implicate bFGF in the process of smooth muscle cell proliferation and an effective and specific antiproliferative potency of bFGF-specific antisense oligonucleotides. The results point to possible new therapeutic strategies for the use of antisense methodology in the suppression of post-angioplasty restenosis.