A nanoparticulate pre-chemosensitizer for efficacious chemotherapy of multidrug resistant breast cancer

Small-molecule chemosensitizers can reverse cancer multidrug resistance (MDR), thus significantly improving the in vitro effect of chemotherapy drugs for MDR cancer cells, however, their in vivo effects are not always very good, because they are difficult to effectively accumulate in tumor and enter the same cancer with chemotherapy drugs after systemic administration due to individual biopharmaceutical properties. To overcome these limitations, here we study a novel nanoparticular pre-chemosensitizer which can be also used as nanocarrier of chemotherapy drugs. We take an 'all in one' approach to develop a self-assembled nanoparticle formula of amphiphilic poly(curcumin-dithiodipropionic acid)-b-poly(ethylene glycol)-biotin. The nanoparticle is capable of tumor-targeted delivery, responsive degradation at the intracellular level of glutathione and subsequent intracellular co-release of the chemosensitizer curcumin and the encapsulated chemotherapeutic drug doxorubicin to maximize a synergistic effect of chemosensitization and chemotherapy. We demonstrate that the antitumor efficacy of nanoparticle is much superior to that of doxorubicin in the multidrug resistant MCF-7/ADR xenografted nude mice.