Acid-sensitive reactive oxygen species triggered dual-drug delivery systems for chemo-photodynamic therapy to overcome multidrug resistance

In clinical treatment, multidrug resistance (MDR) is one of the major obstacles resulting in the failure of chemotherapy. It is still a challenge to overcome MDR. Herein, we fabricated intelligent dextran-based dual-drug delivery systems histidine modified dextran conjugated doxorubicin/zinc porphyrin/paclitaxel (DHTD/Zn-TPP/PTX) via supramolecular metallo-coordination for synergistic chemo-photodynamic therapy to overcome cancer drug resistance. In this designed DHTD/Zn-TPP/PTX, one anticancer drug (doxorubicin, DOX) was conjugated on the dextran backbone through a reactive oxygen species sensitive linker and the other drug PTX was encapsulated into the acid responsive supramolecular micelles formed by the photosensitizer Zn-TPP and histidine grafted on dextran. DHTD/Zn-TPP/PTX with excellent stability could be effectively internalized by tumour cells. In the acidic tumour environment, the loaded PTX and Zn-TPP as photosensitizer could be released; moreover, when irradiated with light the conjugated DOX could be specifically released because the linker broke. As the obtained data indicate, DHTD/Zn-TPP/PTX exhibited not only an enhanced anticancer therapeutic effect but also significant growth inhibition for drug-resistant MCF-7/ADR cells to reverse MDR, having great potential for synergistic treatments of cancer to overcome MDR. © 2020 Society of Chemical Industry