Amphiphilic Peptides for Efficient siRNA Delivery

Area of Science:

• Biotechnology and Biomedical Engineering
• Nanomedicine and Drug Delivery

Background:

• Triple-negative breast cancer (TNBC) presents significant therapeutic challenges.
• Effective intracellular delivery of small interfering RNA (siRNA) is crucial for gene silencing-based cancer therapies.
• Amphiphilic cyclic peptides are explored as potential non-viral vectors for nucleic acid delivery.

Purpose of the Study:

• To synthesize and evaluate amphiphilic cyclic peptides for efficient siRNA delivery into TNBC cell lines.
• To investigate the synergistic effect of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) on peptide-mediated siRNA delivery and gene silencing.
• To assess the toxicity profile of the developed peptide-siRNA formulations.

Main Methods:

• Solid-phase peptide synthesis (Fmoc/tBu) to create cyclic peptides ([FR]4, [WR]5, [WK]5, [R6K]W6, [R5K]W5).
• In vitro evaluation of siRNA delivery efficiency in MDA-MB-231 and MDA-MB-468 TNBC cell lines.
• Assessment of gene silencing (KSP, JAK2) and cell viability assays.
• Co-formulation studies with the lipid DOPE.

Main Results:

• The [WR]5 peptide demonstrated the highest siRNA delivery efficiency, exceeding other cyclic peptides by over 3-fold.
• Co-formulation with DOPE significantly enhanced [WR]5-mediated siRNA delivery by approximately 2-fold.
• Peptides containing arginine and tryptophan residues ([R5K]W5, [R6K]W6) also showed improved siRNA delivery, further enhanced by DOPE.
• No significant toxicity was observed for the evaluated peptides at N/P ratios of 20:1 or less.

Conclusions:

• Amphiphilic cyclic peptides, particularly those rich in tryptophan and arginine, are effective carriers for siRNA delivery in TNBC cells.
• DOPE acts as a potent enhancer for peptide-based siRNA delivery and subsequent gene silencing.
• These peptide-DOPE formulations represent a promising strategy for targeted gene therapy in breast cancer with a favorable safety profile.