Doxorubicin loaded singlet-oxygen producible polymeric micelle based on chlorine e6 conjugated pluronic F127 for overcoming drug resistance in cancer

Drug resistance remains one of the primary obstacles to the success of cancer chemotherapy. In this work, we demonstrate a singlet-oxygen producible polymeric (SOPP) micelle based on photosensitizer (PS, chlorin e6 (Ce6)) conjugated amphiphilic copolymer (pluronic F127^®, PF127) for overcoming drug resistance in cancer by applying photochemical internalization (PCI). The doxorubicin (DOX)-loaded SOPP micelles were self-assembled from Ce6-PF127 conjugates, which have a spherical shape with a uniform size of ∼30 nm. Compared with free Ce6, enhanced singlet-oxygen generation efficiency in the DOX-loaded SOPP micelles have been demonstrated in aqueous environments due to their increased water-dispersibility. Under low dose of laser power and anti-cancer drug (DOX) conditions, in vitro and in vivo studies on drug-resistant cancer cells demonstrated that singlet-oxygen-mediated cellular membrane damage (caused by lipid peroxidation) significantly increased the cellular uptake of drug (DOX), which led to overcoming the drug resistance in cancer cells without undesirable side effects. We believe this approach could represent a promising platform for drug-resistant cancer treatment.