Targeted osteosarcoma chemotherapy using RGD peptide-installed doxorubicin-loaded biodegradable polymeric micelle

Osteosarcoma is the most common primary malignant bone tumor in the pediatric age group, and chemotherapy directed by targeted nanoparticulate drug delivery system represents a promising approach for osteosarcoma treatment recently. Here, we designed and developed a novel DOX-loaded targeted polymeric micelle self-assembled from RGD-terminated poly(ethylene glycol)-block-poly (trimethylene carbonate) (RGD-PEG-PTMC) amphiphilic biodegradable block copolymer, for high-efficiency targeted chemotherapy of osteosarcoma. Notably, the RGD-installed DOX-loaded biodegradable polymeric micelle (RGD-DOX-PM) with drug loading efficiency of 57%-73% displayed a narrow distribution (PDI=0.05-0.12) with average sizes ranging from 46 to 73nm depending on the DOX loading content. The release amount of DOX from RGD-DOX-PM achieved 63% within 60h under physiological condition. Interestingly, MTT assays in MG-63 and MNNG/HOS osteosarcoma cells exhibited that half-maximal inhibitory concentration (IC₅₀) value of RGD-DOX-PM was much lower than its non-targeted counterpart (DOX-PM), implying RGD decorated nanoparticles had enhanced cell targeting ability and led to more effective anti-tumor effect. Furthermore, the targeting ability of RGD-DOX-PM was confirmed by in vitro flow cytometry and confocal laser scanning microscopy (CLSM) imaging assays, where the results showed more RGD-DOX-PM were taken up by MG-63 cells than that of DOX-PM. Therefore, this RGD decorated DOX-loaded polymeric micelle is promising for targeted chemotherapy of osteosarcoma.