Dual-responsive TPGS crosslinked nanocarriers to overcome multidrug resistance

Abstract

Efficient delivery of chemotherapeutic agents into tumor cells and reversal of chemoresistance are crucially important to enhance cancer therapy. We fabricated pH/redox dual responsive nanocarriers based on cell penetrating peptides (TAT) functionalized TPGS (cTAT-TPGS) and polypeptide (PEG-b-poly(aspartic-lipoic acid), PPAL) to reduce the permanent drug release and overcome multidrug resistance. TAT was used to functionalize TPGS and shielded by pH-responsive fatty acids, and polypeptides with lipoic acid side chains (PPAL) were synthesized. Reversibly crosslinked hybrid micelles (RCMs) were fabricated based on cTAT-TPGS and PPAL. RCMs nanocarriers exhibited acid-responsive charge reversal and redox-responsive drug release. The in vitro results showed that the RCMs could be efficiently internalized by the MCF-7/ADR cells in an acidic microenvironment and inhibited the DOX efflux, causing a higher cytotoxicity than non-crosslinked nanocarriers. Furthermore, the dual-responsive structure effectively prolonged the circulation time of RCM nanocarriers and achieved a high level of accumulation in cancer cells in vivo, leading to much more effective inhibition of tumor growth. The DOX-loaded RCMs also showed excellent biosafety, especially for the myocardium tissue. This novel strategy provided an effective platform for drug target delivery and reversal of MDR.