Ludwig Institute for Cancer Research, Brussels Branch, and de Duve Institute, Université Catholique de Louvain, B-1200 Brussels, Belgium.
Proc Natl Acad Sci U S A. 2012 Feb 14;109(7):2497-502. doi: 10.1073/pnas.1113873109. Epub 2012 Jan 30.
Tryptophan catabolism mediated by indoleamine 2,3-dioxygenase (IDO1) is an important mechanism of peripheral immune tolerance contributing to tumoral immune resistance, and IDO1 inhibition is an active area of drug development. Tryptophan 2,3-dioxygenase (TDO) is an unrelated hepatic enzyme that also degrades tryptophan along the kynurenine pathway. Here, we show that enzymatically active TDO is expressed in a significant proportion of human tumors. In a preclinical model, TDO expression by tumors prevented their rejection by immunized mice. We developed a TDO inhibitor, which, upon systemic treatment, restored the ability of mice to reject TDO-expressing tumors. Our results describe a mechanism of tumoral immune resistance based on TDO expression and establish proof-of-concept for the use of TDO inhibitors in cancer therapy.
色氨酸分解代谢由吲哚胺 2,3-双加氧酶(IDO1)介导,是导致肿瘤免疫抵抗的外周免疫耐受的重要机制,IDO1 抑制是药物开发的活跃领域。色氨酸 2,3-双加氧酶(TDO)是一种不相关的肝酶,也沿着犬尿氨酸途径降解色氨酸。在这里,我们表明,具有酶活性的 TDO 在很大比例的人类肿瘤中表达。在临床前模型中,肿瘤中 TDO 的表达阻止了免疫小鼠对其的排斥。我们开发了一种 TDO 抑制剂,全身性治疗后,恢复了小鼠排斥表达 TDO 的肿瘤的能力。我们的结果描述了基于 TDO 表达的肿瘤免疫抵抗机制,并为在癌症治疗中使用 TDO 抑制剂建立了概念验证。