A potentiometric screen-printed biosensor for analysis of Kynurenine production to overcome immune barriers to different cancer cell progression

Analysis of kynurenine (Kyn) is of great importance in cancer biology. Degradation of tryptophan (Trp) to Kyn by indoleamine-2,3-dioxygenases 1 and 2 (IDO1/2) and tryptophan-2, 3-dioxygenase (TDO) in tumors and tumor-draining lymph nodes inhibits antitumor immune responses and is associated with a poor prognosis in various malignancies. Tumors increase their consumption of the amino acid tryptophan to evade immune control. Many cancers upregulate a liver enzyme, tryptophan dioxygenase, to drive tryptophan consumption. What’s more, the authors find that the primary product of this process, kynurenine, is an endogenous ligand for the aryl hydrocarbon receptor, which mediates invasive tumor growth. This second finding links the fields of toxicology, immunology and cancer biology in new ways, and may help to explain how elevated tryptophan consumption helps tumors to overcome immune barriers to cancer progression. In this work, for the first time, we report on the development of biosensor based on constant current potentiometric stripping analysis (cc-PSA) for determination of Kyn in cancer cell culture media samples [1, 2].