Preparation and characterization of photo-responsive cell-penetrating peptide-mediated nanostructured lipid carrier

Tumor-oriented nanocarrier drug delivery approaches with photo-sensitivity have been drawing considerable attention over the years. Here we described a nanostructured lipid carrier (NLC) modified with photo-responsive cell-penetrating peptides (pCPP-NLC). The conventional cell penetrating peptide (CPP)-mediated intracellular drug delivery system sometimes seemed limited due to the lack of target selectivity of the cell penetrating activity. In this study, pCPP (CKRRMK(Nvoc)WK(Nvo0c)K(Nvoc)), a photo-responsive CPP originated from the CPP (CKRRMKWKK), was endowed photo-responsiveness after masking of lysines in the sequence of CPP with photolabile-protective groups, and was introduced onto the surface of NLC. Accordingly, upon reaching the tumor tissues, pCPP-NLC enhance specific cancer cellular uptake after rapidly cleaving the photolabile-protective group, in this case, illumination in the presence of UV-light. In contrast, in circulation, the penetration was shielded. The pCPP-NLC carrying paclitaxel (PTX) prepared in this work possessed suitable physiochemical properties such as small particle size, high drug encapsulation efficiency, and good stability. The strong cellular uptake and cytotoxic activity of pCPP-NLC in HT-1080 cells verified the correlation with illumination. The remarkable penetration into HT-1080 multicellular tumor spheroids confirmed that the temporary mask of the photolabile-protective group in pCPP does not disturb the penetration ability of CPP in the tumor microenvironment with illumination. Furthermore, the triggered activation exhibited higher antitumor efficacy with the tumor spheroids compared with the non-modified NLC (N-NLC) and Taxol(®). In conclusion, the application of pCPP modifications may be an approach for the selectively targeted delivery of anti-tumor agents.