Paclitaxel and quercetin co-loaded functional mesoporous silica nanoparticles overcoming multidrug resistance in breast cancer.

Multidrug resistance (MDR) in tumor has long been considered a major factor in the failure of tumor chemotherapy. P-glycoprotein (P-gp)-mediated drug efflux plays a significant role in the MDR of tumor. Herein, paclitaxel (PTX) and P-gp inhibitor quercetin (QC) co-loaded and chondroitin sulfate (ChS)-coated mesoporous silica nanoparticles (MSNs) (MSNs-ChS@PQ) were developed to reverse MDR in breast cancer and improve chemotherapy efficacy. The dual drug-loaded nanoparticles (NPs) showed a nanoscale size of ∼ 227.2 nm and redox-responsive drug release property. In vitro cell experiments showed that NPs exhibited CD44 receptor-mediated active targeting in MCF-7/ADR cells. The dual drug-loaded NPs had lower IC50 value, higher apoptosis rate, obvious G2M phase arrest as well as stronger microtubule destruction in MCF-7/ADR cells compared to PTX-loaded NPs, suggesting that QC addition, significantly, improved the sensitivity of MCF-7/ADR cells to PTX. Further study found that QC-loaded NPs down-regulated the expression of P-gp. Notably, the dual drug-loaded NPs exhibited tumor-targeting ability, prolonged tumor retention time and effective anti-tumor effect without obvious toxicity to normal tissues in vivo. Taken together, our research provides a viable approach to overcome MDR in breast cancer.