A series of novel conjugates comprising tublin and IDO inhibitors were designed, synthesized and evaluated for their antiproliferative activity. Among them, HI5, composed of combretastatin A-4 (CA-4) and (D)-1-methyltryptophan (D-MT) by a linker, exhibited the most potent antitumor activity, in particular with higher IC50 value (0.07 μM) than CA-4 (0.21 μM) against HeLa cancer cell line. Mechanism studies indicated that HI5 can inhibit tubulin polymerization and cell migration, cause G2/M phase arrest, concurrent induce apoptosis via the mitochondrial dependent apoptosis pathway and cause reactive oxidative stress generation in HeLa cells. Furthermore, HI5 can inhibit IDO expression and decrease kynurenine production, leading to stimulating T cells activation and proliferation to enhance antitumor immunity in vitro. Interestingly, HI5 can effectively limit the tumor growth in the HeLa xenograft mice models without causing significant loss of body weight. Consequently, such a conjugation can be a potent and safe immunochemotherapeutic method for improving cancer therapy.

中文翻译：

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双功能偶联物通过抑制微管蛋白聚合和吲哚胺-2,3-双加氧酶改善癌症免疫化疗。

设计、合成了一系列包含微管蛋白和 IDO 抑制剂的新型偶联物，并评估了它们的抗增殖活性。其中，由combretastatin A-4 (CA-4)和(D)-1-甲基色氨酸(D-MT)通过接头组成的HI5表现出最有效的抗肿瘤活性，特别是具有更高的IC50值（0.07 μM）比 CA-4 (0.21 μM) 对抗 HeLa 癌细胞系。机制研究表明，HI5 可以抑制微管蛋白聚合和细胞迁移，导致 G2/M 期阻滞，同时通过线粒体依赖性凋亡途径诱导细胞凋亡，并导致 HeLa 细胞产生反应性氧化应激。此外，HI5 可以抑制 IDO 表达并减少犬尿氨酸的产生，从而刺激 T 细胞活化和增殖，从而增强体外抗肿瘤免疫。有趣的是，HI5 可以有效地限制 HeLa 异种移植小鼠模型中的肿瘤生长，而不会导致体重显着下降。因此，这种结合可以是一种用于改善癌症治疗的有效且安全的免疫化学治疗方法。