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Tumor-targeted paclitaxel delivery and enhanced penetration using TAT-decorated liposomes comprising redox-responsive poly(ethylene glycol).

To combine the advantage of poly(ethylene gylcol) (PEG) for longer circulation and cell-penetrating peptides (CPPs) for efficient cellular uptake, paclitaxel (PTX)-loaded liposomes functionalized with TAT, the most frequently used CPP, and cleavable PEG via a redox-responsive disulfide linker (PTX-C-TAT-LP) were successfully developed here. Under physiological conditions, TAT was shielded by PEG layer and liposomes exhibited a long blood circulation. At tumor site, PEG could be detached in the presence of exogenous reducing agent [glutathione (GSH)] and TAT was exposed to facilitate cell internalization. In the presence of GSH, the liposomal vesicle C-TAT-LP showed increased cellular uptake and improved three-dimensional tumor spheroids penetration in vitro compared with analogous stable shielded liposomes. C-TAT-LP achieved enhanced tumor distribution and demonstrated superior delivery efficiency in vivo. PTX-C-TAT-LP with GSH strongly inhibited the proliferation of murine melanoma B16F1 tumor cells in vitro and in vivo with the tumor inhibition rate being 69.4% on B16F1-bearing mice. In addition, the serum aspartate transaminase level, alanine transaminase level, and creatine kinase level were almost completely within normal range in the PTX-C-TAT-LP with GSH group, revealing PTX-C-TAT-LP with GSH had no obvious drug-related adverse events for liver and heart. Taken together, C-TAT-LP is a promising tumor-targeting drug carrier.