Multifunctional, self-assembling, anionic peptide-lipid nanocomplexes for targeted siRNA delivery

Formulations of cationic liposomes and polymers readily self-assemble by electrostatic interactions with siRNA to form cationic nanoparticles which achieve efficient transfection and silencing in vitro. However, the utility of cationic formulations in vivo is limited due to rapid clearance from the circulation, due to their association with serum proteins, as well as systemic and cellular toxicity. These problems may be overcome with anionic formulations but they provide challenges of self-assembly and transfection efficiency. We have developed anionic, siRNA nanocomplexes utilizing anionic PEGylated liposomes and cationic targeting peptides that overcome these problems. Biophysical measurements indicated that at optimal ratios of components, anionic PEGylated nanocomplexes formed spherical particles and that, unlike cationic nanocomplexes, were resistant to aggregation in the presence of serum, and achieved significant gene silencing although their non-PEGylated anionic counterparts were less efficient. We have evaluated the utility of anionic nanoparticles for the treatment of neuronal diseases by administration to rat brains of siRNA to BACE1, a key enzyme involved in the formation of amyloid plaques. Silencing of BACE1 was achieved in vivo following a single injection of anionic nanoparticles by convection enhanced delivery and specificity of RNA interference verified by 5' RACE-PCR and Western blot analysis of protein

Targeted Therapy and Immunotherapy for Heterogeneous Breast Cancer

Breast cancer (BC) is the most common malignancy in women worldwide, and it is a molecularly diverse disease. Heterogeneity can be observed in a wide range of cell types with varying morphologies and behaviors. Molecular classifications are broadly used in clinical diagnosis, including estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), epidermal growth factor receptor (EGFR), vascular endothelial growth factor receptor (VEGFR), and breast cancer gene (BRCA) mutations, as indicators of tumor heterogeneity. Treatment strategies differ according to the molecular subtype. Besides the traditional treatments, such as hormone (endocrine) therapy, radiotherapy, and chemotherapy, innovative approaches have accelerated BC treatments, which contain targeted therapies and immunotherapy. Among them, monoclonal antibodies, small-molecule inhibitors and antibody–drug conjugates, and targeted delivery systems are promising armamentarium for breast cancer, while checkpoint inhibitors, CAR T cell therapy, cancer vaccines, and tumor-microenvironment-targeted therapy provide a more comprehensive understanding of breast cancer and could assist in developing new therapeutic strategies

Hepatic Carcinoma Selective Nucleic Acid Nanovector Assembled by Endogenous Molecules Based on Modular Strategy

We rationally formulated a nucleic acid nanovector platform utilizing endogenous molecules in the following steps: nucleic acids are initially packed by a multifunctional peptide and a cationic liposome to form positively charged ternary complexes through electrostatic interaction; then the ternary complexes were coated with hyaluronic acid (HA) to form negatively charged quaternary nanocomplexes (Q-complexes). Among the components of Q-complexes, the multifunctional peptide was composed of a poly-16-arginine (R₁₆) and a hepatic tumor-targeted cell penetrating peptide (KRPT­MRFR­YTWN­PMK); the cationic lipid component included DOTAP and fusogenic lipid DOPE; the HA component shielded the cationic ternary complexes and actively targeted the CD44 overexpressed on the surface of tumor cells. Q-complexes have showed a relatively high stability in the medium, and HA component partially separated from the nanocomplexes after the Q-complexes bound to the cancer cells. The Q-complexes showed significantly enhanced nucleic acid delivery activity than the corresponding quaternary complexes containing R₁₆ and nonvisible cytotoxicity in SCMM-7721 cells. <i>In vivo</i>, a selected Q-complex HLP₁R specifically targeted and entered tumor cells without affecting normal tissues. Furthermore, HLP₁R wrapped survivin siRNA efficiently and silenced the targeting gene in the liver orthotropic transplantation tumor models and showed nontoxic <i>in vivo</i>. This study reveals that Q-complexes are reasonable and feasible gene therapeutic carriers

Polyspermine imine, a pH Responsive Polycationic siRNA Carrier Degradable to Endogenous Metabolites

Cationic polymers readily degradable in response to cellular environment are especially favored as easy-formulating materials to pack siRNA into a nanoparticle and to release the cargo in the cytoplasm in time. In addition to the efficiency of cytosomal release, the degradation products should best be free of safety concerns, a typical challenge for cationic polymers. To satisfy the two criteria, we report a new cationic polymer, polyspermine imine, named as PSP-Imine, which is formed by condensing two endogenous molecules, spermine and glyoxal, through conjugated π linkage, NCCN (Schiff base reaction), a poly linkage structure sufficiently stable under neutral condition but dissociative under the endosomal pH. Cellular assays under a confocal microscope indicated that the polyplex formed of PSP-Imine readily released the loaded siRNA to the cytoplasm after being engulfed in the target cells and efficiently silenced the target genes in different cell lines and xenograft mouse model of human cervical carcinoma, as compared with nondegradable PEI 25 kDa. Cell viability assays confirmed that PSP-Imine showed no visible cytotoxicity within the concentration being tested. The present study suggests that PSP-Imine is an excellent siRNA condensing material for forming the core of a therapeutically feasible synthetic carrier system