A polyethylenimine-modified carboxyl-poly(styrene/acrylamide) copolymer nanosphere for co-delivering of CpG and TGF-β receptor I inhibitor with remarkable additive tumor regression effect against liver cancer in mice

Shuyan Liang,* Jun Hu,* Yuanyuan Xie, Qing Zhou, Yanhong Zhu, Xiangliang Yang National Engineering Research Center for Nanomedicine, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, People’s Republic of China *These authors contributed equally to this work Abstract: Cancer immunotherapy based on nanodelivery systems has shown potential for treatment of various malignancies, owing to the benefits of tumor targeting of nanoparticles. However, induction of a potent T-cell immune response against tumors still remains a challenge. In this study, polyethylenimine-modified carboxyl-styrene/acrylamide (PS) copolymer nanospheres were developed as a delivery system of unmethylated cytosine-phosphate-guanine (CpG) oligodeoxynucleotides and transforming growth factor-beta (TGF-β) receptor I inhibitors for cancer immunotherapy. TGF-β receptor I inhibitors (LY2157299, LY) were encapsulated to the PS via hydrophobic interaction, while CpG oligodeoxynucleotides were loaded onto the PS through electrostatic interaction. Compared to the control group, tumor inhibition in the PS-LY/CpG group was up to 99.7% without noticeable toxicity. The tumor regression may be attributed to T-cell activation and amplification in mouse models. The results highlight the additive effect of CpG and TGF-β receptor I inhibitors co-delivered in cancer immunotherapy. Keywords: CpG, TGF-β receptor I inhibitor, Pst-AAm copolymer nanosphere, immunotherapy