Epirubicin-Complexed Polypeptide Micelle Effectively and Safely Treats Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related mortality worldwide. Epirubicin (EPI) once acted as a main agent for HCC chemotherapy. However, the dosage-dependent side effects seriously limit its application in clinic. The purpose of this study is to develop an effective nanocarrier to improve the efficacy and overcome the limitations of EPI. In this regard, the EPI-complexed micelle (i.e., mPEG-b-PGA/EPI) was prepared via the electrostatic interaction between the amino group in EPI and the carboxyl group in PGA segment of methoxy poly(ethylene glycol)-block-poly(L-glutamic acid) (mPEG-b-PGA), and the subsequent hydrophobic interaction among PGA/EPI complexes. The micelle appeared spherical with a diameter at around 90 nm and possessed a pH-sensitive release property of payload. The cytotoxicity and hemolysis assays in vitro, and the maximum tolerated dose tests in vivo confirmed that mPEG-b-PGA was a kind of safe material with excellent biocompatibility, while the drug-loaded micelle could obviously improve the tolerance of EPI. In addition, mPEG-b-PGA/EPI possessed significantly enhanced antitumor efficacy and security toward the H22-xenografted HCC murine model at macroscopic and microscopic levels compared with free EPI. All these results strongly indicate that mPEG-b-PGA/EPI may be a promising nanoplatform for EPI delivery in the chemotherapy of HCC.