Indoleamine 2,3-dioxygenase 1 inhibition targets anti-PD1-resistant lung tumors by blocking myeloid-derived suppressor cells

Indoleamine 2,3-dioxygenase 1 (IDO1), involved in the catabolism of tryptophan (Trp) to kynurenine (Kyn) is an important regulator of tumor-mediated immunosuppression implicated in resistance to anti-PD1 immunotherapy. We investigated the role of IDO1 in an anti-PD1-resistant lung cancer model (344SQ_R) compared to the parental 344SQ tumors (344SQ_P). IDO1 was overexpressed in tumor-infiltrating leukocytes, and plasma Kyn levels were increased, in 344SQ_R vs. 344SQ_P. The IDO1 inhibitor INCB023843 retarded tumor growth and reduced lung metastases in 344SQ_R.

Source: Cancer Letters - May 7, 2018 Category: Cancer & Oncology Authors: Ailin Li, Hampartsoum B. Barsoumian, Jonathan E. Schoenhals, Taylor R. Cushman, Mauricio S. Caetano, Xiaohong Wang, David R. Valdecanas, Sharareh Niknam, Ahmed I. Younes, Guang Li, Wendy A. Woodward, Maria Angelica Cortez, James W. Welsh Tags: Original Articles Source Type: research