Arginine-rich ionic complementary peptides as potential drug carriers: Impact of peptide sequence on size, shape and cell specificity.

Ionic complementary peptides have shown potential in delivering hydrophobic anticancer drugs. In this study, a series of four ionic complementary peptides, EAR16-II, EAR8-II, EAR8-IIa and ELR8-IIa, is derived from the most studied ionic complementary peptide EAK16-II. The purpose is to investigate the impact of peptide sequence on nanostructure formation, delivery efficacy and cell specificity of the peptide-drug complex. We show that the peptide length has a pronounced impact on the morphology of peptide complex with the anticancer drug ellipticine (EPT), and the amino acid arrangement affects the complex size. Cytotoxicity studies show that the complexes are effective at inhibiting the growth of A549 lung cancer cells and EAR16-II-EPT is the most effective. Interestingly, the complexes formulated with EAR16-II and EAR8-II become less active against MCF-7 breast cancer cells, but more hemolytic than the other two complexes. This work provides essential information to optimize self-assembling peptide-based drug delivery for cancer therapy.