PEGylated liposomes with NGR ligand and heat-activable cell-penetrating peptide–doxorubicin conjugate for tumor-specific therapy

Cell-penetrating peptides (CPPs) mediated tumor-oriented nanocarriers have been widely studied by researchers recently. However, applications of CPPs in vivo were usually hampered by their loss in untargeted tissues and enzymatic degradation. These shortfalls required strategies to camouflage CPPs before their arrival at the targeted site. In this work, we constructed a thermosensitive liposome (TSL) containing Asparagines–Glycine–Arginine (NGR) peptide as the targeting moiety and heat-activable cell-penetrating peptide–doxorubicin conjugate for enhancing specific cancer therapy. Different to the masking strategies of CPPs reported, CPPs existing in conjugation form of CPPs and doxorubicin (CPP-Dox) were hidden in TSL to cloak and protect CPPs. Meanwhile, NGR moiety and local tumor hyperthermia were utilized to achieve specific targeting of CPPs to the tumor. The nanocarrier (CPP-Dox/NGR-TSL) prepared in this work possessed suitable physiochemical properties such as small particle size of about 90 nm, high drug encapsulation efficiency of approximately 95%, good stability in the medium containing 10% fetal bovine serum (FBS) and so on. In vitro experiments on Human fibrosarcoma cells (HT-1080) and human breast adenocarcinoma cells (MCF-7) verified the specific targeting ability and enhanced intracellular drug delivery of the liposomes to HT-1080 cells. Furthermore, comparing with NGR-targeted TSL containing Dox (Dox/NGR-TSL), the results of intravenous administration showed CPP-Dox/NGR-TSL significantly inhibited tumor growth in nude mice xenografted HT-1080 tumors and excellent body safety. In conclusion, the nanocarrier constructed in this study would be a safe and efficiently drug delivery system for specific cancer treatment.