The transcription factor E2F regulates the expression of several genes concerned with cell growth. The ability to inhibit transcription by blocking E2F expression has great potential in the treatment of proliferative disorders. The effect of double-stranded phosphorothioate oligonucleotides containing E2F transcription factor cis element, a so called 'decoy' has examined on the growth of cultured human Tenon's fibroblastic cells. Human Tenon's fibroblastic cells were cultured and challenged by E2F decoy coated with the Hemagglutinating virus of Japan (HVJ) cationic liposomes (HVJ-CL). The outcome was evaluated using fluorescence microscopy, RT-PCR and growth assays. HVJ-CL facilitated the transfer of external oligonucleotides to cultured human Tenon's fibroblastic cells. The E2F decoy, transferred by HVJ-CL, inhibited simultaneously the expression of the mRNAs of several cell cycle related genes such as c-myc, cdc2, proliferative cell nuclear antigen, and dehydrofolate reductase. Entry into S phase was also reduced to 42.7% of the positive control by the E2F decoy. The total increase of DNA at four days was reduced to 59.7% of the positive control by 5 microM and 29.9% by 15 microM of E2F decoy. It is concluded that gene therapy using the E2F transcription factor offers a potential therapeutic modality for the treatment of proliferative disorders such as proliferative vitreoretinopathy and fibrosis following filtering surgery.