We have recently developed an anisamide-targeted nanoparticle formulation, called LPD, for intravenous delivery of siRNA to human lung cancer cells NCI-H460 (expressing the sigma receptor) in an athymic nude mouse model. The siRNA was designed to silence the epidermal growth factor receptor (EGFR). As the result of a high level of uptake by the tumor (70-80% injected dose per g of tissue), the EGFR was completely silenced through out the entire tumor. Despite the high efficiency delivery of the siRNA and silencing of the target oncogene, the tumor cells only showed a partial (~15%) apoptosis and partial growth inhibition in vivo. Thus, the project will develop several independent strategies to enhance the therapeutic activity mediated by LPD.
In aim 1, we will encapsulate multiple sets of siRNA targeting to different cellular oncogenes to show at least an additive, if not synergistic, effect in tumor killing. Let-7 miRNA will also be tested for its tumor suppression activity in the model. Chemically modified siRNA including those containing boranophosphate will also be tested for prolonged silencing effect. We have discovered that cationic lipid DOTAP, which is a major component in the LPD formulation, shows an anti-apoptotic activity which protects the tumor cells from death. We have discovered another cationic lipid which by itself kills tumor cells and can be used to replace DOTAP in the siRNA formulation. Preliminary data indicate that the anisamide targeted LPD can also deliver siRNA to the pulmonary metastasis of mouse melanoma B16F10 cells.
In aim 2, we will deliver different siRNA to induce apoptosis of the melanoma cells in mice. We will also test a splice shifting oligo which will convert the anti-apoptotic Bcl-xL to the apoptotic Bcl-xS to induce tumor cell death. Since the delivery system can also deliver a plasmid DNA along with siRNA, different anti-cancer genes can be used in a combination therapy with siRNA.
In aim 3, we will employ another nanoparticle formulation, i.e., LPH, which contains heparin sulfate to deliver doxorubicin (dox), a potent anti-cancer drug, either by itself or together with EGFR siRNA. Since dox and EGFR silencing induce apoptosis by different mechanisms, we expect at least an additive, if not synergistic, effect. Dox will be chemically conjugated to heparin sulfate and co-formulated in LPH. The goal of the project is to develop efficient anti-tumor nanoparticle agents for cancer therapy.
The goal of the project is to develop a tumor specific, systemic delivery system for siRNA for cancer therapy. A self-assembled nanoparticle formulation will be used as a delivery vehicle. The project uses lung cancer and lung metastasis in mice as the disease model.
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