Lablog4-52:Reversal of indoleamine 2,3-dioxygenase-mediated cancer immune suppression by systemic kynurenine depletion with a therapeutic enzyme.

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Todd A Triplett, Kendra C Garrison, Nicholas Marshall, Moses Donkor, John Blazeck, Candice Lamb, Ahlam Qerqez, Joseph D Dekker, Yuri Tanno, Wei-Cheng Lu, Christos S Karamitros, Kyle Ford, Bing Tan, Xiaoyan M Zhang, Karen McGovern, Silvia Coma, Yoichi Kumada, Mena S Yamany, Enrique Sentandreu, George Fromm, Stefano Tiziani, Taylor H Schreiber, Mark Manfredi, Lauren I R Ehrlich, Everett Stone, George Georgiou

First author

Todd A Triplett

Corresponding author

George Georgiou

Publication Style

Journal name Nature biotechnology


Volume, issue, pages

36(8) 758-764


Increased tryptophan (Trp) catabolism in the tumor microenvironment (TME) can mediate immune suppression by upregulation of interferon (IFN)-γ-inducible indoleamine 2,3-dioxygenase (IDO1) and/or ectopic expression of the predominantly liver-restricted enzyme tryptophan 2,3-dioxygenase (TDO)1,2,3,4,5. Whether these effects are due to Trp depletion in the TME or mediated by the accumulation of the IDO1 and/or TDO (hereafter referred to as IDO1/TDO) product kynurenine (Kyn) remains controversial5,6,7,8,9,10,11,12,13. Here we show that administration of a pharmacologically optimized enzyme (PEGylated kynureninase; hereafter referred to as PEG-KYNase) that degrades Kyn into immunologically inert, nontoxic and readily cleared metabolites inhibits tumor growth. Enzyme treatment was associated with a marked increase in the tumor infiltration and proliferation of polyfunctional CD8+ lymphocytes. We show that PEG-KYNase administration had substantial therapeutic effects when combined with approved checkpoint inhibitors or with a cancer vaccine for the treatment of large B16-F10 melanoma, 4T1 breast carcinoma or CT26 colon carcinoma tumors. PEG-KYNase mediated prolonged depletion of Kyn in the TME and reversed the modulatory effects of IDO1/TDO upregulation in the TME.