Two-Pronged Anti-Tumor Therapy by a New Polymer-Paclitaxel Conjugate Micelle with an Anti-Multidrug Resistance Effect

Introduction: Cancerous tumors are still a major disease that threatens human life, with tumor multidrug resistance (MDR) being one of the main reasons for the failure of chemotherapy. Thus, reversing tumor MDR has become a research focus of medical scientists. Methods: Here, a reduction-sensitive polymer prodrug micelle, mPEG-DCA-SS-PTX (PDSP), was manufactured with a new polymer inhibitor of drug resistance as a carrier to overcome MDR and improve the anti-tumor effect of PTX. Results: The PDSP micelles display good stability, double-responsive drug release, and excellent biocompatibility. The PDSP micelles reduced the cytotoxicity of PTX to normal HL-7702 cells and enhanced that to SMMC-7721 and MCF-7 cells in vitro. Improved sensitivity of A549/ADR to PDSP was also observed in vitro. Furthermore, in vivo experiments show reduced systemic toxicity and enhanced therapeutic efficacy of PTX to H22 subcutaneous tumor-bearing mice. Conclusion: This work proves that the reduction-sensitive polymer prodrug micelles carried by the new polymer inhibitor can be used as an alternative delivery system to target tumors and reverse MDR for paclitaxel and other tumor-resistant drugs.