Application of tumor-targeting peptide-decorated polypeptide nanoparticles with doxorubicin to treat osteosarcoma

Osteosarcoma is the most common primary malignant bone tumor in childhood and adolescence. Currently, surgery combined with chemotherapy is the main treatment for osteosarcoma. However, the long-term survival of patients with metastatic osteosarcoma is unsatisfactory. Therefore, new treatment methods to improve the prognosis of patients with osteosarcoma are required. The present study aimed to develop nanocarriers with both tumor targeting and reduction responsiveness abilities, and to improve the therapeutic effect and reduce toxicity by loading traditional small molecule antitumor drugs. The tumor targeting peptide-decorated, doxorubicin (DOX)-loaded mPEG-P(Phe-co-Cys) nanoparticles were developed successfully through the ring-opening polymerization of amino acids. The peptide VATANST (STP) can specifically bind with vimentin, which is highly expressed on the osteosarcoma cell surface, resulting in tumor targeting effects. The nanoparticle is core–shell structured to protect the loaded DOX during blood flow. The disulfide bonds within the nanoparticles are sensitive to the osteosarcoma microenvironment, which has high glutathione (GSH) levels. Under the enhanced permeability and retention and active tumor targeting effects, the STP-decorated DOX-loaded nanoparticles accumulated in tumor tissues. High GSH levels can rupture disulfide bonds, resulting in the controlled release of DOX, which will cause necrosis of tumor cells. The characteristics of the synthesized nanoparticles, DOX release profiles in vitro and in vivo, cytotoxicity analysis, animal study, and safety evaluation were performed. The nanoparticles could increase the tumor inhibition efficiency against osteosarcoma and reduce the side effects of DOX to major organs. The STP-decorated mPEG-P(Phe-co-Cys) nanoparticles might be a suitable drug delivery system for DOX to treat osteosarcoma.