title: Targeting TDO in cancer immunotherapy.
abstract: Tryptophan-2,3-dioxygenase (TDO) is a homotetrameric heme-containing protein catalyzing the initial step in the kynurenine pathway, which oxidates the 2,3-double bond of the indole ring in L-tryptophan and catalyzes it into kynurenine (KYN). The upregulation of TDO results in a decrease in tryptophan and the accumulation of KYN and its metabolites. These metabolites can affect the proliferation of T cells. Increasing evidence demonstrates that TDO is a promising therapeutic target in the anti-tumor process. Despite its growing popularity, there are only a few reviews focusing on TDO in tumors. Hence, we herein review the biological features and regulatory mechanisms of TDO. Additionally, we focus on the role of TDO in the anti-tumor immune response in different tumors. Finally, we also provide our viewpoint regarding the future developmental directions of TDO in cancer research, especially in relation to the development and application of TDO inhibitors as novel cancer treatments.
authors.affiliation: The Second Clinic Medical College, School of Medicine, Nanchang University, Nanchang, China.
authors.forename: Cheng-Peng
authors.initials: CP
authors.lastname: Yu
authors.affiliation: Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Nanchang University, Nanchang, China.
authors.forename: Yun-Lei
authors.initials: YL
authors.lastname: Song
authors.affiliation: Department of Gastrointestinal Surgery, The Second Affiliated Hospital of Nanchang University, Nanchang, China.
authors.forename: Zheng-Ming
authors.initials: ZM
authors.lastname: Zhu
authors.affiliation: Department of Pathology, The Affiliated Infectious Diseases Hospital of Nanchang University, Nanchang, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Huang
authors.affiliation: Department of Pathology, The Affiliated Infectious Diseases Hospital of Nanchang University, Nanchang, China.
authors.forename: Ying-Qun
authors.initials: YQ
authors.lastname: Xiao
authors.affiliation: Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Nanchang University, Nanchang, China. luodaya@ncu.edu.cn.|Jiangxi Province Key Laboratory of Tumor Pathogens and Molecular Pathology, Nanchang University, Nanchang, China. luodaya@ncu.edu.cn.
authors.forename: Da-Ya
authors.initials: DY
authors.lastname: Luo
mesh_terms: D000818:Animals; D006801:Humans; D007167:Immunotherapy / Q000379:methods*; D058990:Molecular Targeted Therapy; D009369:Neoplasms / Q000201:enzymology* / Q000276:immunology / Q000628:therapy*; D014366:Tryptophan Oxygenase / Q000037:antagonists & inhibitors* / Q000276:immunology* / Q000378:metabolism
chemical_list: D014366:Tryptophan Oxygenase
keywords: Immunomodulation; TDO; Tryptophan metabolism; Tumor