Human Health, Performance and Recreation, Robbins College of Health and Human Sciences, Baylor University, Waco, TX 76798-7346, USA.
Human Science and Design, Robbins College of Health and Human Sciences, Baylor University, Waco, TX 76798-7346, USA.
Nutrients. 2021 Apr 3;13(4):1189. doi: 10.3390/nu13041189.
Tryptophan metabolism, via the kynurenine (Kyn) pathway, and microbial transformation of tryptophan to indolic compounds are fundamental for host health; both of which are altered in colon carcinogenesis. Alterations in tryptophan metabolism begin early in colon carcinogenesis as an adaptive mechanism for the tumor to escape immune surveillance and metastasize. The microbial community is a key part of the tumor microenvironment and influences cancer initiation, promotion and treatment response. A growing awareness of the impact of the microbiome on tryptophan (Trp) metabolism in the context of carcinogenesis has prompted this review. We first compare the different metabolic pathways of Trp under normal cellular physiology to colon carcinogenesis, in both the host cells and the microbiome. Second, we review how the microbiome, specifically indoles, influence host tryptophan pathways under normal and oncogenic metabolism. We conclude by proposing several dietary, microbial and drug therapeutic modalities that can be utilized in combination to abrogate tumorigenesis.
色氨酸代谢途径（通过犬尿氨酸途径）和色氨酸转化为吲哚化合物的微生物转化对于宿主健康至关重要，而这两者在结肠癌变中都会发生改变。在结肠癌变的早期，色氨酸代谢的改变是肿瘤为逃避免疫监视和转移而产生的一种适应性机制。微生物群落是肿瘤微环境的关键组成部分，影响癌症的发生、促进和治疗反应。人们越来越意识到微生物组对致癌作用下色氨酸（Trp）代谢的影响，这促使我们进行了本次综述。我们首先比较了正常细胞生理条件下和结肠癌变过程中宿主细胞和微生物组中色氨酸代谢的不同途径。其次，我们综述了微生物组，特别是吲哚，如何在正常和致癌代谢下影响宿主色氨酸途径。最后，我们提出了几种可以联合使用的饮食、微生物和药物治疗方式来消除肿瘤发生。
