Beijing National Laboratory for Molecular Sciences, Center for Soft Matter Science and Engineering, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, People's Republic of China.
School of Life Science and Technology, University of Electronic Science and Technology of China , Chengdu 610054, People's Republic of China.
J Am Chem Soc. 2018 Jan 24;140(3):1170-1178. doi: 10.1021/jacs.7b13017. Epub 2018 Jan 11.
Cyclization and polymer conjugation are two commonly used approaches for enhancing the pharmacological properties of protein drugs. However, cyclization of parental proteins often only affords a modest improvement in biochemical or cell-based in vitro assays. Moreover, very few studies have included a systematic pharmacological evaluation of cyclized protein-based therapeutics in live animals. On the other hand, polymer-conjugated proteins have longer circulation half-lives but usually show poor tumor penetration and suboptimal pharmacodynamics due to increased steric hindrance. We herein report the generation of a head-to-tail interferon-poly(α-amino acid) macrocycle conjugate circ-P(EGGlu)-IFN by combining the aforementioned two approaches. We then compared the antitumor pharmacological activity of this macrocycle conjugate against its linear counterparts, N-P(EGGlu)-IFN, C-IFN-P(EGGlu), and C-IFN-PEG. Our results found circ-P(EGGlu)-IFN to show considerably greater stability, binding affinity, and in vitro antiproliferative activity toward OVCAR3 cells than the three linear conjugates. More importantly, circ-P(EGGlu)-IFN exhibited longer circulation half-life, remarkably higher tumor retention, and deeper tumor penetration in vivo. As a result, administration of the macrocyclic conjugate could effectively inhibit tumor progression and extend survival in mice bearing established xenograft human OVCAR3 or SKOV3 tumors without causing severe paraneoplastic syndromes. Taken together, our study provided until now the most relevant experimental evidence in strong support of the in vivo benefit of macrocyclization of protein-polymer conjugates and for its application in next-generation therapeutics.
环化和聚合物缀合是增强蛋白质药物的药理学性质的两种常用方法。然而，亲本蛋白的环化通常仅在生化或基于细胞的体外测定中提供适度的改善。此外，很少有研究包括对活动物中环化蛋白治疗剂的系统药理学评估。另一方面，聚合物缀合的蛋白质具有更长的循环半衰期，但由于空间位阻增加，通常表现出较差的肿瘤穿透和不理想的药效动力学。我们在此报告通过结合上述两种方法生成干扰素-聚（α-氨基酸）大环环化缀合物 circ-P(EGGlu)-IFN。然后，我们比较了这种大环缀合物与线性对应物 N-P(EGGlu)-IFN、C-IFN-P(EGGlu)和 C-IFN-PEG 的抗肿瘤药理活性。我们的结果发现，circ-P(EGGlu)-IFN 比三种线性缀合物具有更大的稳定性、结合亲和力和对 OVCAR3 细胞的体外增殖抑制活性。更重要的是，circ-P(EGGlu)-IFN 在体内表现出更长的循环半衰期、显著更高的肿瘤保留和更深的肿瘤穿透。结果，施用大环缀合物能够有效地抑制荷有人 OVCAR3 或 SKOV3 移植瘤的小鼠的肿瘤进展并延长其存活时间，而不会引起严重的副肿瘤综合征。总之，我们的研究提供了迄今为止最相关的实验证据，强烈支持了蛋白质-聚合物缀合物大环化的体内益处，并为其在下一代治疗中的应用提供了支持。
