Targeting and sensitizing MDR cancer by an MMP2 and pH dual-responsive ZnO-based nanomedicine

Zinc oxide nanoparticles (ZnO NPs) have been known as a therapeutic agent and drug delivery system for treating various diseases, including infectious diseases and cancer. However, due to the low biocompatibility, short in vivo half-life, and potential toxicity, the previous studies on ZnO NPs were mainly focused on their in vitro applications. The effective and safe ZnO NP-based systems which can be used for in vivo drug delivery have been rarely reported. In this study, we developed a novel dual-responsive hybrid ZnO NP (ZnO/DPPG/PEG-pp-PE) consisting of the ZnO NPs, phospholipid (DPPG), and enzyme-sensitive amphiphilic polymer (PEG-pp-PE), which could respond to both tumoral matrix metalloproteinase 2 (MMP2) and intracellular acidic pH, for tumor-targeted drug delivery and multidrug resistant (MDR) cancer treatment. The dual-responsive ZnO/DPPG/PEG-pp-PE could easily load the model drug, doxorubicin (DOX), and showed excellent physicochemical properties, stability, and MMP2 and pH dual sensitivity. The ZnO/DPPG/PEG-pp-PE/DOX showed the MMP2-dependent cellular uptake, enhanced cell penetration, and improved anticancer activity in the MDR cancer cells and their spheroids. In the MDR tumor-bearing mice, the ZnO/DPPG/PEG-pp-PE/DOX improved the biocompatibility, tumor targetability, and anticancer activity of DOX and ZnO without significant toxicity compared to the free DOX, ZnO/DOX, and nonsensitive ZnO NPs. The data suggested that the dual-sensitive ZnO-based nanomedicine could be a promising delivery system for targeted drug delivery and therapy against the MDR cancer.