Thermoresponsive Supramolecular Chemotherapy by “V”-Shaped Armed β-Cyclodextrin Star Polymer to Overcome Drug Resistance

Abstract

Pump mediated drug efflux is the key reason to result in the failure of chemotherapy. Herein, a novel star polymer β-CD-v-(PEG-β-PNIPAAm)₇ consisting of a β-CD core, grafted with thermo-responsive poly(N-isopropylacrylamide) (PNIPAAm) and biocompatible poly(ethylene glycol) (PEG) in the multiple "V"-shaped arms is designed and further fabricated into supramolecular nanocarriers for drug resistant cancer therapy. The star polymer could encapsulate chemotherapeutics between β-cyclodextrin and anti-cancer drug via inclusion complex (IC). Furthermore, the temperature induced chain association of PNIPAAm segments facilitated the IC to form supramolecular nanoparticles at 37 °C, whereas the presence of PEG impart great stability to the self-assemblies. When incubated with MDR-1 membrane pump regulated drug resistant tumor cells, much higher and faster cellular uptake of the supramolecular nanoparticles were detected, and the enhanced intracellular retention of drugs could lead to significant inhibition of cell growth. Further in vivo evaluation showed high therapeutic efficacy in suppressing drug resistant tumor growth without a significant impact on the normal functions of main organs. This work signifies thermo-responsive supramolecular chemotherapy is promising in combating pump mediated drug resistance in both in vitro and in vivo models, which may be encouraging for the advanced drug delivery platform design to overcome drug resistant cancer.

A novel thermoresponsive star polymer consisting of β-CD, PNIPAAm, and PEG in V"-shaped arms of β-CD-g-(PEG-v-PNIPAAm)₇ is designed to address the great challenges in drug-resistant cancer therapy. Chemotherapeutics such as PTX and DOX are encapsulated into β-CD host cavity via inclusion complex and further self-assembled into stable supramolecular nanoparticles at 37 °C to combat MDR1 membrane pump-mediated drug resistance.

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