Enhanced Gene Silencing through Human Serum Albumin-Mediated Delivery of Polyethylenimine-siRNA Polyplexes

Abstract

Small interfering RNA (siRNA) targeted therapeutics (STT) offers a compelling alternative to tradition medications for treatment of genetic diseases by providing a means to silence the expression of specific aberrant proteins, through interference at the expression level. The perceived advantage of siRNA therapy is its ability to target, through synthetic antisense oligonucleotides, any part of the genome. Although STT provides a high level of specificity, it is also hindered by poor intracellular uptake, limited blood stability, high degradability and non-specific immune stimulation. Since serum proteins has been considered as useful vehicles for targeting tumors, in this study we investigated the effect of incorporation of human serum albumin (HSA) in branched polyethylenimine (bPEI)-siRNA polyplexes in their internalization in epithelial and endothelial cells. We observed that introduction of HSA preserves the capacity of bPEI to complex with siRNA and protect it against extracellular endonucleases, while affording significantly improved internalization and silencing efficiency, compared to bPEI-siRNA polyplexes in endothelial and metastatic breast cancer epithelial cells. Furthermore, the uptake of the HSA-bPEI-siRNA ternary polyplexes occurred primarily through a caveolae-mediated endocytosis, thus providing evidence for a clear role for HSA in polyplex internalization. These results provide further impetus to explore the role of serum proteins in delivery of siRNA.

ECM turnover-stimulated gene delivery through collagen-mimetic peptide-plasmid integration in collagen

“…This interaction would decrease the charge of the polyplex, diminishing the tendency for polyplexes to aggregate or be degraded post release. Pre-exposure of PEI polyplex and other positively charged nanoparticles to serum has previously been documented to have this effect [62, 63]. …”

“…The integration of polyplex in collagen, along with serum protein adsorption, has also been shown to affect cellular uptake mechanisms, with these interactions suggested to lead to greater endocytic uptake and/or more efficient intracellular trafficking to the nucleus [63, 64]. In fact, our studies supported the existence of these effects in the CMP-polyplex materials, showing that the higher amounts of GPP peptide affected not only polyplex release kinetics, but the polyplex’s final composition.…”

Stearyl polyethylenimine complexed with plasmids as the core of human serum albumin nanoparticles noncovalently bound to CRISPR/Cas9 plasmids or siRNA for disrupting or silencing PD-L1 expression for immunotherapy

“…HSA-branched PEI (bPEI)-siRNA ternary complexes formed with native unmodified HSA were reported to significantly improve the internalization and silencing efficiency, compared to bPEI-siRNA polyplexes. 31 Further, a new NP formulation composed of HSA for codelivery of doxorubicin (DOX) 32 or PTX 33 and the tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) by employing Nab technology was developed to demonstrate the potential of complexing ligands with albumin via charge interactions between the positive surface charge of the TRAIL and the negative surface charge of HSA in a neutral condition to encapsulate anticancer drugs, such as DOX and PTX. Based on this concept, when adjusting HSA to an acidic condition lower than its isoelectric point of about 5, the positive charge of HSA is able to complex with the negative charge of siRNA, and then NPs are formed by Nab technology enabling the codelivery of chemotherapeutic drugs and siRNA.…”

Poly (1-Vinyl Imidazole) Polyplexes as Novel Therapeutic Gene Carriers for Lung Cancer Therapy

“…Two hours post-administration, the polyplexes are found to be inside the cells and remain even after 16 hours ( Figure 3B). The localization of the polyplexes was found to be the cytosol which is preferable for gene silencing as the RISC 22 is formed in the cytoplasm.…”