Design of Block Copolymer Micellar Aggregates for Co-Delivery of Enzyme and Anticancer Prodrug.

Traditional enzyme-prodrug therapy (EPT) is a two-step strategy, which has many serious deficiencies, so having a one-step EPT treatment becomes a problem of immediate interest. This study aims to achieve an effective co-delivery of horseradish peroxidase (HRP) as a kind of enzyme for prodrug activation and ethyl 3-indoleacetate (EIA) as anticancer prodrug. A ternary block copolymer PEG-PAsp(AED)-CA consisting of poly(ethylene glycol) (PEG), reduction-sensitive poly (N-(2,2'-dithiobis(ethylamine)) aspartamide) PAsp(AED), and cholic acid (CA) was synthesized and assembled into spherical micelles which encapsulated EIA in its hydrophobic core and HRP in a reduction-sensitive interlayer. TEM photographs show that the polymer micelle is around 40 nm, and the cell survival rate test shows that the EIA/HRP polymer micelle is highly lethal to human lung adenocarcinoma cells. Thus, co-delivery of EIA and HRP demonstrates great potential in cancer therapy, offering a structurally simple and highly tunable platform for the synchronous delivery of enzymes and prodrugs in EPT.