Asymmetric liposome particles with highly efficient encapsulation of siRNA and without nonspecific cell penetration suitable for target-specific delivery

Abstract

The discovery of siRNA has been an important step in gene therapy, but the problem of delivering siRNA to a target organ limits its use as a therapeutic drug. Liposomes can be used as a nonviral vector to deliver siRNA to target cells. In this study we developed a novel method of producing asymmetric liposome particles (ALPs) with highly efficient siRNA encapsulation. Two kinds of lipid inverted micelles were prepared for the purpose of obtaining ALPs. The inner one is composed of ionizable cationic 1,2-dioleoyl-3-dimethylammonium-propane (DODAP) and 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), which entrap siRNA, and the outer one is composed of 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), DOPE, polyethylene glycol-1,2-distearoyl-sn-glycero-3-phosphatidylethanolamine (PEG-PE), and cholesterol. After mixing the inverted micelles, ALPs encapsulating siRNA were obtained by solvent evaporation and dialysis. This process allowed more than 90% siRNA encapsulation as well as the negatively charged surface. The ALPs protected siRNA from ribonuclease A degradation. ALPs without any surface modification elicited almost no uptake into cells, while the surface-modified ALPs with a polyarginine peptide (R12) induced nonspecific cell penetration. The conjugation of the anti-human epidermal growth factor receptor antibody (anti-EGFR) to ALPs induces an EGFR-mediated uptake into the non-small cell lung cancer cell lines but not into NIH-3T3 cells without the receptor. The siRNA encapsulated in ALPs showed the R12- or anti-EGFR-dependent target gene silencing in NCI-H322 cells. These properties of ALPs are useful for target-specific delivery of siRNA after modification of ALPs with a target-specific ligand.

Nanotoxicity: A Key Obstacle to Clinical Translation of siRNA-Based Nanomedicine

“…For certain diseases, such as cancer, passive targeting based on an enhanced permeation and retention effect can increase tumor drug accumulation [113], however, the improvement is often moderate. Therefore, siRNA nanocarriers developed in recent years have often been functionalized with active-targeting moieties, such as mono-clonal antibodies, receptor substrates and cell-penetrating peptides [90,114–116]. The advantage of this active-targeting strategy is illustrated in the study of asymmetric liposome particles, which were designed with the positive charges on the inner surface to minimize the nonspecific cellular uptake [114].…”

“…Therefore, siRNA nanocarriers developed in recent years have often been functionalized with active-targeting moieties, such as mono-clonal antibodies, receptor substrates and cell-penetrating peptides [90,114–116]. The advantage of this active-targeting strategy is illustrated in the study of asymmetric liposome particles, which were designed with the positive charges on the inner surface to minimize the nonspecific cellular uptake [114]. Only after decorating asymmetric liposome particles with anti-EGFR could receptor-mediated uptake into lung cancer cell lines but not into the EGFR-free NIH-3T3 cells be effectively induced.…”

Hybridization Between Natural Extract of Angelica gigas Nakai and Inorganic Nanomaterial of Layered Double Hydroxide via Reconstruction Reaction

“…target-specific drug delivery to an intended lesion. [5][6][7][8][9] Encapsulation of bio-active substances with liposome or polymer nanoparticles as well as rearrangement of active molecules within inorganic nanomaterials have been tried to achieve enhanced transportation efficacy and modified release. 10 11 Among various nanomaterials, layered inorganics such as layered double hydroxides (LDHs) and clays have attracted increasing interests due to their unique 2-dimensional structures which can modulate the molecular arrangement of payload resulting in enhanced stability and controlled release property.…”

N0436 (Alliance): A Phase II Trial of Irinotecan With Cetuximab in Patients With Metastatic Breast Cancer Previously Exposed to Anthracycline and/or Taxane-Containing Therapy

“…23 This blocks the phosphorylation and activation of receptor-associated tyrosine kinases, leading to tumoricidal effects. 24 Preclinical studies have demonstrated growth suppression of EGFR-overexpressing tumors. 25-28 …”