A recent increase in approval of nucleic acid therapeutics received strong interest in the field. However, their clinical application needs a suitable delivery system. Cell-penetrating peptides (CPPs) are one of the promising candidates. We hypothesized to synthesize a series of fatty acylated CPPs, X-(R)n-(HR)4, (where X is a flexible hydrophobic chain (oleic acid) and n = 0,1,2,3, 4 or 5) and (HR)4 is a CPP) which contain cationic and hydrophobic residues to encapsulate siRNA and deliver it in the cells. Fatty acylated CPPs were synthesized using fmoc solid-phase peptide synthesis, followed by purification and characterization. The cytotoxicity profile of peptide-siRNA complexes was evaluated using cell viability assay, which demonstrated 100% cell viability up to 20 µM in the selected breast cancer cell lines (MCF-7 and MDA-MB-231) and normal breast cells (MCF-10A). The gel retardation assay indicates that most peptides bind completely with siRNA at N/P ratio 5 and above. The serum stability data suggest that the peptides protect siRNA at N/P ratio 20 and above when incubated with 25% FBS for 24 h. Flow cytometry and confocal microscopy data reveal the significant uptake of Alexa-488 labeled siRNA into the cytoplasm of breast cancer cells (MDA-MB-231 and MCF-7) using Oleyl-R5-(HR)4 peptide. Preliminary western blotting data with Oleyl-R3-(HR)4 and Oleyl-R5-(HR)4 shows that the peptides-siRNA delivery system can silence STAT-3 for up to 70 %. The study reveals that fatty acylated CPPs serve as effective delivery vehicles for siRNA in several breast cancer cell lines with significant silencing of target genes.

Fatty acylated cell-penetrating peptides for siRNA delivery to silence STAT-2 in the triple negative breast cancer

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.