Enhancement of anti-herpetic activity of antisense phosphorothioate oligonucleotides 5' end modified with geraniol

We have previously shown that antisense phosphorothioate oligonucleotide (SON) targeted against immediate early (IE) pre-mRNA5 of the herpes simplex virus type I (HSV-I) possessed potent anti-herpetic activities in vitro system. However, anti-herpetic activities of SON were not still efficient enough. Lipophilic compounds have been often conjugated with antisense oligonucleotide to enhance the biological activity. In this study, we selected geraniol as a lipophilic compound and newly synthesized SON bearing 5' terminal geraniol (geranyl-SON) toward IE pre-mRNA 5 of the HSV-1 to enhance the anti-herpetic activity. Geraniol is a olefinic terpene alcohol which is found in many essential oils. It possesses lipophilic characteristic. It is thought to be absorbed in tissue. Geraniol enhanced the anti-herpetic activity of SON with less cytotoxicity in a sequence specific manner. Terminal modification with geraniol did not affect binding affinity with complimentary DNA. Cytoplasm distribution of geranyl-SON was confirmed by confocal microscope. While some of the geranyl-SON was seen in the nucleus, unmodified SON had a punctate distribution in the cytoplasm with little in the nucleus. These results suggested that geranyl modification enhances anti-herpetic activity by changing the subcellular distribution of the oligonucleotides. Consequently geraniol-modifica-tion could provide new means for the efficient delivery of oligo-nucleotides.