Synthesis and In Vitro Evaluation of Amphiphilic Peptides and Their Nanostructured Conjugates

Purpose: Breast cancer is the second leading cancer type among people of advanced countries. Various methods have been used for cancer treatment such as chemotherapy and radiotherapy. In the present study we have designed and synthesized a new group of drug delivery systems (DDS) containing a new class of Cell Penetrating Peptides (CPPs) named Peptide Amphiphiles (PAs). Methods: Two PAs and anionic peptides were synthesized using solid phase peptide synthesis (SPPS), namely [KW] 4, [KW] 5, E4 and E8. Then nano-peptides were synthesized by non-covalent binding between PAs and poly anions as [KW] 4-E4, [KW] 4-E8, [KW] 5-E4 and [KW] 5-E8. Results: Flow cytometry studies showed that increased chain length of PAs with a higher ratio between hydrophobicity and net charge results in increased intracellular uptake by MCF7 cells after 2h incubation. Moreover, nano-peptides showed greater intracellular uptake compared to PAs. Anti-proliferative assay revealed that by increasing chain length of PAs, the toxicity effect on MCF7 cells is reduced, however nano-peptides did not show significant toxicity on MCF7 cells even at high concentration levels. Conclusion: These data suggest that due to the lack of toxicity effect at high concentration levels and also high cellular uptake, nano-peptides are more suitable carrier compared to PAs for drug delivery.