A pH-responsive complex based on supramolecular organic framework for drug-resistant breast cancer therapy.

Chemotherapy is one of the main ways to treat breast cancer clinically. However, the multidrug resistance to anti-tumor drugs limits their clinical use. To overcome these drawbacks, development of drug delivery systems (DDSs) has attracted more and more attention in cancer therapy. At present, the preparation and purification process are complicated for many reported DDSs, while clinic calls for new DDSs that are more convenient for preparation. Here, a new pH-responsive supramolecular organic framework drug delivery complex loading doxorubicin (DOX) is fabricated. Anti-tumor activity of the system in vitro was investigated by cell cytotoxicity, uptake assay, and cell apoptosis analysis. The anti-tumor activity in vivo was investigated by inspecting nude mice body weight, tumor volume, and weight, also a preliminary mechanism probe was conducted by HE and TUNEL staining. The DOX@SOF displayed high stability, good biocompatibility, and pH regulated drug release. At acid condition, the hydrazone bonds would be broken, which result in the dissociation of SOF, and then the drugs would be released from the system. Furthermore, DOX@SOF enhanced cellular internalization. Both in vitro and in vivo experiments reflected that DOX@SOF could enhance the anti-tumor activity of DOX for the MCF-7/ADR tumor cells and tumors. This study provides a highly efficient strategy to prepare stimulus-responsive supramolecular drug delivery complex for treatment of drug-resistant cancer, the results presented inspiring scientific interests in exploring new drug delivery strategy and reversing multi-drug resistance for clinical chemotherapy.