Contents lists available at ScienceDirect Journal of Controlled Release journal homepage: www.elsevier.com/locate/jconrel A PEGylated hyaluronic acid conjugate for targeted cancer immunotherapy Jung Min Shin a,1 , Se Jin Oh b,c,d,1 , Seunglee Kwon a , V.G. Deepagan a , Minchang Lee a , Seok Ho Song a , Hyo-Jung Lee b,c,d , Suyeon Kim b,c,d , Kwon-Ho Song b,c,d , Tae Woo Kim b,c,d,e,⁎ , Jae Hyung Park a,⁎⁎ a School of Chemical Engineering, College of Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea b Laboratory of Tumor Immunology, Department of Biomedical Sciences, Graduate School of Medicine, Korea University, Seoul 02841, Republic of Korea c Department of Biochemistry and Molecular Biology, College of Medicine, Korea University, Seoul 02841, Republic of Korea d Department of Biomedical Science, College of Medicine, Korea University, Seoul 02841, Republic of Korea e Translational Research Institute for Incurable Diseases, College of Medicine, Korea University, Seoul 02841, Republic of Korea ARTICLE INFO Keywords: Cancer immunotherapy Foreignization Antigen delivery Hyaluronic acid PEGylation Matrix metalloproteinase 9 (MMP9) ABSTRACT The cell-free approach to foreignizing tumor cells with non-self antigens has received increasing attention as a method to induce cytotoxic T lymphocyte (CTL)-mediated immunological rejection of tumors, because the clinical translation of the conventional CTL-based cancer immunotherapies has been limited by a complicated manufacturing process and autotransplantation. In this study, we prepared matrix metalloproteinase 9 (MMP9)- responsive polymeric conjugates consisting of PEGylated hyaluronic acid (HA) as the targeting moiety and ovalbumin (OVA) as the model foreign antigen. The MMP9-cleavable linker was introduced between PEG and the HA backbone to facilitate the detachment of the PEG corona from the conjugate at the tumor site. From the in vitro cellular uptake study, it was revealed that the conjugate was effectively taken up by the CD44-expressing TC-1 cancer cells in the presence of MMP9 via receptor-mediated endocytosis. When the conjugate was sys- temically administered into the tumor-bearing mice with endogenous OVA-specific CTLs, the tumor growth was markedly inhibited, which was attributed to the significant antigen presentation on the tumor cells. Overall, the MMP9-responsive conjugates bearing foreign antigens might have the potential as an alternative to CTL-based cancer immunotherapeutics. 1. Introduction CD8 + cytotoxic T lymphocytes (CTLs) have been explored as a tool to eliminate target cells with antigenic peptides presented by surface major histocompatibility complex (MHC) class I molecules [1–3]. Therefore, CTL-based cancer immunotherapies such as adoptive cell therapy (ACT) and engineered chimeric antigen receptor (CAR) T cell therapy have shown the potential to treat cancer without side effects [4–7]. In the clinic, these therapies have exhibited statistically sig- nificant improvement over conventional chemotherapy and radio- therapy by avoiding non-specific cell death [8–10]. Although ACT and CAR T cell therapies are effective strategies to overwhelm cancer, they require a high cost, a complicated manufacturing process and auto- grafting, limiting their extended applications to cancer patients [11–13]. Besides, most existing approaches for CTL activation focus on delivering tumor antigen to antigen-presenting cells not tumors. In this regard, the innovative cell-free approach to foreignizing tumor cells via site-specific non-self antigen delivery can be an option to induce the CTL-mediated immunological rejection of tumors. Recently, we re- ported on a hyaluronic acid (HA)-based polymeric conjugate as a po- tential immunotherapeutic agent to foreignize cancer cells by deli- vering the antigen via receptor-mediated endocytosis [14]. Owing to its specific binding affinity to the HA receptor (CD44), the conjugate was selectively taken up by the cancer cells, resulting in high antitumor efficacy after its systemic administration into the tumor-bearing mice [15]. The conjugate, however, exhibited significant accumulation in the liver. This might be due to its uptake by phagocytic cells in the re- ticuloendothelial system and by liver sinusoidal endothelial cells ex- pressing the other HA receptor (stabilin-2), and thus requires a strategy to minimize the liver accumulation of the conjugate [16,17]. In recent years, stimuli-sensitive drug delivery systems have emerged to treat intractable diseases, since they release the drug at the http://dx.doi.org/10.1016/j.jconrel.2017.08.032 Received 3 May 2017; Received in revised form 14 August 2017; Accepted 23 August 2017 ⁎ Correspondence to: Tae Woo Kim, Laboratory of Tumor Immunology, Department of Biomedical Sciences, Graduate School of Medicine, Korea University, Seoul 02841, Republic of Korea. ⁎⁎ Corresponding author. 1 These authors contributed equally to this paper. E-mail addresses: twkim0421@korea.ac.kr (T.W. Kim), jhpark1@skku.edu (J.H. Park). Journal of Controlled Release 267 (2017) 181–190 Available online 26 August 2017 0168-3659/ © 2017 Published by Elsevier B.V. T