Mixed micelles based on hyaluronic acid-poly(propylene glycol) and pluronic L61 for targeted doxorubicin delivery to multi-drug resistance MCF-7 cells

摘要

Introduction: Doxorubicin (DOX) is a widely used in chemotherapeutic anticancer drug. However, DOX showed limited anticancer effects for multi drug resistance (MDR) cancer cells, which has been considered as one of big challenges. To overcome MDR in cancer cells, diverse efflux pump inhibitors like small molecule inhibitors and polymeric inhibitors have been developed. In this study, polymeric mixed micelles incorporating Dox was designed not only to overcome MDR in cancer cells but also to deliver chemotherapeutic drug to target cancer cells. After synthesizing hyaluronic acid-poly (propylene glycol) (HP) block copolymers, HP was mixed with pluronic L61 (HPL) to fabricated mixed micelles. Physical stability, loading efficiency, and particle sizes were examined using HP and HPL micelles. The amount of intracellular uptake into MCF-7/MDR cancer cells were assessed using three types of samples including free DOX, DOX in HP, and DOX in HPL. Anticancer effects by DOX in HPL mixed micelles were also examined by cell viability assay for MCF-7/MDR cancer cells. Materials and Method: The stability of micelles was evaluated by monitoring the particle size distribution of the micelles while suspended in deionized water and kept in 37°C for 5days. To compare the amount of uptake DOX through various micelles, MCF-7/MDR cells were treated with free DOX, DOX loaded pluronic F-127, HP, HPL 3, S, 40% at a DOX concentration 2.6 μM. The cells treated with free DOX and DOX loaded various micelles were incubated for 3hr at 37°C and then the cells were incubation more 3hr after changing medium. The lysosomal membranes of the cells were disrupted by triton X-100. After centrifugation, the supernatant was measured by fluorospectrophotometer at excitation and emission 480 and 595nm. Results and Discussion: The stability of HP and HPL were evaluated by measuring their hydrodynamic diameter using a dynamic light scattering instrument. As shown in Fig1., the stability of HPL is better than HP. The aggregation of HP has been formed during 5 day, while HPL showed the better stability. To compare the amount of uptake of DOX, free DOX, DOX in micelles were treated to MDR cancer cells. As shown in Fig 2, while the amount of uptake of free DOX was negligible, the amount of DOX in micelles in cancer cells was greatly higher than free DOX. In the case of comparing various micelles, the DOX in HPL 3% was shown the most amount of uptake. Conclusions: In this study, HP graft copolymer was synthesized and characterized. HPL mixed micelles showed greatly improved particle stability and loading efficiency of DOX, compared to HP micelles. In addition, DOX in HPL was much more successfully internalized into MCF-7/MDR cells than free DOX. Therefore, HPL mixed micelles can serve as a nanocarrier for targeted chemotherapeutics for MDR cancer cells.