Codelivery of doxorubicin and elacridar to target both liver cancer cells and stem cells by polylactide-co-glycolide/d-alpha-tocopherol polyethylene glycol 1000 succinate nanoparticles

Dazhong Chen,1–3,* Xiaoli Pan,4,* Fangyuan Xie,5,* Ying Lu,2 Hao Zou,2 Chuan Yin,6 Yu Zhang,7 Jie Gao1,2 1Department of Gastrointestinal Surgery, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou 325027, China; 2Department of Pharmaceutical Sciences, Second Military Medical University, Shanghai 200433, China; 3Department of Planning, Kunming General Hospital of Chengdu Military Command, Yunnan 650032, China; 4Division of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; 5Department of Pharmacy, Shanghai Eastern Hepatobiliary Surgery Hospital, Shanghai 200438, China; 6Department of Gastroenterology, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China; 7Department of Oncology, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Hubei 441000, China *These authors contributed equally to this work Purpose: Liver cancer is the third leading cause of cancer-related deaths worldwide. Liver cancer stem cells (LCSCs) are a subpopulation of cancer cells that are responsible for the initiation, progression, drug resistance, recurrence, and metastasis of liver cancer. Recent studies have suggested that the eradication of both LCSCs and liver cancer cells is necessary because the conversion of cancer stem cells (CSCs) to cancer cells occasionally occurs. As ATP-binding cassette (ABC) transporters are overexpressed in both CSCs and cancer cells, combined therapies using ABC transporter inhibitors and chemotherapy drugs could show superior therapeutic efficacy in liver cancer. In this study, we developed poly(lactide-co-glycolide)/d-alpha-tocopherol polyethylene glycol 1000 succinate nanoparticles to accomplish the simultaneous delivery of an optimized ratio of doxorubicin (DOX) and elacridar (ELC) to target both LCSCs and liver cancer cells.Methods: Median-effect analysis was used for screening of DOX and ELC for synergy in liver cancer cells (HepG2 cells) and LCSCs (HepG2 tumor sphere [HepG2-TS]). Then, nanoparticles loaded with DOX and ELC at the optimized ratio (NDEs) were prepared by nanoprecipitation method. The cytotoxicity and colony and tumor sphere formation ability of nanoparticles were investigated in vitro, and the tissue distribution and antitumor activity of nanoparticles were evaluated in vivo.Results: We demonstrated that a DOX/ELC molar ratio of 1:1 was synergistic in HepG2 cells and HepG2-TS. NDEs were shown to exhibit significantly increased cytotoxic effects against both HepG2 and HepG2-TS compared with DOX-loaded nanoparticles (NDs) or ELC-loaded nanoparticles (NEs) in vitro. In vivo studies demonstrated that the nanoparticles exhibited better tumor targeting, with NDE showing the strongest antitumor activity with lower systemic toxicity.Conclusion: These results suggested that NDE represented a promising combination therapy against liver cancer by targeting both liver cancer cells and CSCs. Keywords: combined therapy, cancer stem cells, liver cancer, doxorubicin, elacridar, nanoparticles&nbsp