Exploiting novel placental homing peptides for targeted drug delivery in breast cancer.

More effective drug formulations are needed to increase the selectivity and efficacy of available chemotherapeutics. We have previously shown that nanoparticles decorated with the tumour homing peptide CGKRK can selectively deliver payloads to the placenta. In this study, we investigated whether two novel placental homing peptides NKGLRNK (NKG) and RSGVAKS (RSG) can be utilized to selectively deliver doxorubicin (DOX) to breast cancer cells. Fluorescence microscopy and flow cytometry showed that NKG and RSG bind to and accumulate in MDA-MB-231 and MCF-7 cells in a time-dependent manner, to a similar extent as CGKRK, but accumulate in healthy MCF-10A cells to a much lesser degree. NKG- and RSG-decorated liposomes facilitated equivalent delivery of DOX to MDA-MB-231 and MCF-7 cells, with a comparable efficacy to CGKRK-decorated liposomes. These findings suggest that NKG and RSG represent novel breast tumour-binding sequences that could be utilized to develop more efficacious targeted breast cancer therapies.