Efficient gene silencing in metastatic tumor by siRNA formulated in surface-modified nanoparticles

Abstract

We have developed a nanoparticle (NP) formulation for systemically delivering siRNA into metastatic tumors. The NP, composed of nucleic acids, a polycationic peptide and cationic liposome, was prepared in a self-assembling process. The NP was then modified by PEG-lipid containing a targeting ligand, anisamide, and thus was decorated for targeting sigma receptor expressing B16F10 tumor. The activity of the targeted NP was compared with the naked NP (no PEGylation) and nontargeted NP (no ligand). The delivery efficiency of the targeted NP was 4-fold higher than the nontargeted NP and could be competed by excess free ligand. Luciferase siRNA was used to evaluate the gene silencing activity in the B16F10 cells, which were stably transduced with a luciferase gene, in a lung metastasis model. The gene silencing activity of the targeted NP was significantly higher than the other formulations and lasted for 4 days. While confocal microscopy showed the naked NP provided no tissue selectivity and non-targeted NP was ineffective for tumor uptake, the targeted NP effectively penetrated the lung metastasis, but not the liver. It resulted in 70-80% gene silencing in the metastasis model after a single i.v. injection (150 μg siRNA/kg). This effective formulation also showed very little immunotoxicity.

Therapeutic targeting in the silent era: advances in non-viral siRNA delivery

“…Banerief et al [77] first demonstrated the use of the selective sigma ligand namely anisamide to mediate efficient targeting of liposomal drugs to sigma receptor-expressing prostate cancer cells in vitro and in vivo. Since then there have been several articles reporting the application of anisamide targeting nanoparticles for the cell specific delivery of therapeutic siRNA [78][79][80] .…”

“…As these ABCD formulations are nearly neutral or even negative in charge, the remarkable gene silencing data when administered systemically must be a result of active cell-specific targeting. Li and colleagues developed a nanoparticle formulation for successfully systemic delivery of siRNA into xenograft [122,80] and metastatic tumours [78,79] which produced anti-cancer effects. In this system, the nucleic acids (siRNAs and carrier DNA), a polycationic peptide (protamine) and a cationic liposome, were initially prepared in a condensed core.…”

“…In this system, the nucleic acids (siRNAs and carrier DNA), a polycationic peptide (protamine) and a cationic liposome, were initially prepared in a condensed core. The resulting core was then modified by PEG-lipid containing the tumour targeting ligand, anisamide (see above) [78][79][80] . The resulting targeted nanoparticles silenced the epidermal growth factor receptor (EGFR) in the tumour and induced ~15% tumour cell apoptosis without any indication of immunotoxicity [122] .…”

RNAi-mediated gene silencing in tumour tissue using replication-competent retroviral vectors

“…Currently available delivery vehicles lack high delivery rates upon intravenous application. Li et al 42 demonstrated specific knockdown of luciferase expression to 20-30% in a lung metastasis mouse model with B16F10 cells stably expressing luciferase. As delivery vehicle nanoparticle-formulated siRNA was …”

siRNA Lipid Nanoparticle Potently Silences Clusterin and Delays Progression When Combined with Androgen Receptor Cotargeting in Enzalutamide-Resistant Prostate Cancer

“…Although preclinical studies in prostate cancer (16) and immune cells (17) are promising, distant tumor delivery has not been tested in the clinic. In order to mitigate this higher Peg-lipid content is used to improve the pharmacodynamic and biodistribution of LNP systems to the tumor site (18)(19)(20).…”