Immunoliposome co-delivery of bufalin and anti-CD40 antibody adjuvant induces synergetic therapeutic efficacy against melanoma

Abstract

Ying Li,1,* Jiani Yuan,1,* Qian Yang,1 Wei Cao,1 Xuanxuan Zhou,1 Yanhua Xie,1 Honghai Tu,2 Ya Zhang,1 Siwang Wang1 1Department of Natural Medicine and Institute of Materia Medica, School of Pharmacy, Fourth Military Medical University, Xi’an, People’s Republic of China; 2Institute for Drug and Instrument Control, Xinjiang Military Area Command, Urumqi, Xinjiang, People’s Republic of China *These authors contributed equally to this work Abstract: Liposomes constitute one of the most popular nanocarriers for improving the delivery and efficacy of agents in cancer patients. The purpose of this study was to design and evaluate immunoliposome co-delivery of bufalin and anti-CD40 to induce synergetic therapeutic efficacy while eliminating systemic side effects. Bufalin liposomes (BFL) conjugated with anti-CD40 antibody (anti-CD40-BFL) showed enhanced cytotoxicity compared with bufalin alone. In a mouse B16 melanoma model, intravenous injection of anti-CD40-BFL achieved smaller tumor volume than did treatment with BFL (average: 117 mm3 versus 270 mm3, respectively); the enhanced therapeutic efficacy through a caspase-dependent pathway induced apoptosis, which was confirmed using terminal deoxynucleotidyl transferase-mediated dUTP-Fluorescein nick end labeling and Western blot assay. Meanwhile, anti-CD40-BFL elicited unapparent body-weight changes and a significant reduction in serum levels of tumor necrosis factor-α, interleukin-1β, interleukin-6, interferon-γ, and hepatic enzyme alanine transaminase, suggesting minimized systemic side effects. This may be attributed to the mechanism by which liposomes are retained within the tumor site for an extended period of time, which is supported by the following biodistribution and flow cytometric analyses. Taken together, the results demonstrated a highly promising strategy for liposomal vehicle transport of anti-CD40 plus bufalin that can be used to enhance antitumor effects via synergetic systemic immunity while blocking systemic toxicity. Keywords: liposomes, bufalin, anti-CD40, chemoimmunotherapy