Oleyl Conjugated Histidine-Arginine Cell-Penetrating Peptides as Promising Agents for siRNA Delivery

Abstract

Recent approvals of siRNA-based products motivated the scientific community to explore siRNA as a treatment option for several intractable ailments, especially cancer. The success of approved siRNA therapy requires a suitable and safer drug delivery agent. Herein, we report a series of oleyl conjugated histidine–arginine peptides as a promising nonviral siRNA delivery tool. The conjugated peptides were found to bind with the siRNA at N/P ratio ≥ 2 and demonstrated complete protection for the siRNA from early enzymatic degradation at N/P ratio ≥ 20. Oleyl-conjugated peptide -siRNA complexes were found to be noncytotoxic in breast cancer cells (MCF-7 and MDA-MB-231) and normal breast epithelial cells (MCF 10A) at N/P ratio of ~40. The oleyl-R3-(HR)4 and oleyl-R4-(HR)4 showed ~80-fold increased cellular uptake in MDA-MB-231 cells at N/P 40. Moreover, the conjugated peptides-siRNA complexes form nanocomplexes (~115 nm in size) and have an appropriate surface charge to interact with the cell membrane and cause cellular internalization. Furthermore, this study provides a proof-of-concept that oleyl-R5-(HR)4 can efficiently silence STAT-3 gene (~80% inhibition) in MDA-MB-231 cells with similar effectiveness to Lipofectamine. Further exploration of this approach holds a great promise in discovering a successful in vivo siRNA delivery agent with a favorable pharmacokinetic profile.

Cell-Penetrating Peptide-Based Delivery of Macromolecular Drugs: Development, Strategies, and Progress

“…According to the literature, CPPs can be divided into synthetic CPPs, chimeric CPPs, and protein-derived CPPs [56]. According to their physical and chemical properties, CPPs can be divided into cationic CPPs, amphipathic CPPs, and hydrophobic CPPs [57]. In addition, according to their composition, CPPs can be divided into cyclic CPPs and linear CPPs.…”

Modified Linear Peptides Effectively Silence STAT-3 in Breast Cancer and Ovarian Cancer Cell Lines

“…Cell-penetrating peptides (CPPs) provide promising carriers for the intracellular delivery of nucleic acids [ 6 ]. CPPs are effective in delivering a wide range of therapeutic molecules, including small molecules, nucleic acids, and proteins with limited toxicity, and are currently further explored in drug delivery studies [ 6 , 7 , 8 , 9 ]. A net cationic charge is a common physicochemical property of most CPPs and is known to facilitate membrane internalization [ 10 ].…”

A Straightforward Method for the Development of Positively Charged Gold Nanoparticle-Based Vectors for Effective siRNA Delivery

“…They exert membrane translocation via mechanisms that remain under investigation [13,14]. The cellular uptake and subsequent gene silencing efficiency of siRNA can be greatly improved by forming non-covalent complexes containing CPPs and siRNA [15][16][17][18], by covalently conjugating them [19][20][21] or by encapsulating siRNA within CPP-functionalized nanoparticles. Some encouraging results have also been seen in vitro [22][23][24] and in vivo [25,26] after complexing siRNA to endosomal escape-facilitating CPPs.…”