Disulfide-linked liposomes: Effective delivery vehicle for Bcl-2 antisense oligodeoxyribonucleotide G3139

Background: Disulfide-linked oligodeoxyribonucleotide (ODN) liposomes were formulated and evaluated for the delivery of antisense ODN G3139 in KB human oral carcinoma cells. Materials and Methods: Liposomes composed of 1,2-di-(9Z-octadecenoyl)-3-trimethylammo-nium-propane(DOTAP)/egg phosphatidylcholine/α-tocopheryl polyethylene glycol 1000 succinate were incorporated with hydrophobized disulfide-linked ODN. Disulfide-linked ODN liposomes were characterized for their size, ODN intracellular delivery, Bcl-2 mRNA and protein expression, growth inhibition, and chemosensitization. Results: Intracellular delivery of ODN with disulfide-linked ODN liposomes was more efficient than that with non-liposomal hydrophobized disulfide-linked ODN. Treatment of the cells with disulfide-linked ODN liposomes resulted in efficient Bcl-2 down-regulation greater than that with hydrophobized disulfide-linked ODN and consistent with that of cellular growth inhibition and the sensitization to daunorubicin in KB cells. Disulfide-linked ODN liposomes exhibited superior colloidal stability during 5-week storage. Conclusion: Disulfide-linked liposomes are effective delivery vehicles for antisense ODN.