The effect of 2-amino-3-carboxymuconate-6-semialdehyde decarboxylase gene overexpression in the kynurenine pathway on the expression levels of indoleamine 2,3-dioxygenase 1 and interferon-γ in inflammatory conditions: an in vitro study

Targeting the kynurenine pathway in gliomas: Insights into pathogenesis, therapeutic targets, and clinical advances

Gliomas, the most prevalent primary brain tumors, continue to present significant challenges in oncology due to poor patient prognosis despite advances in treatment such as immunotherapy and cancer vaccines. Recent research highlights the potential of targeting tryptophan metabolism, particularly the kynurenine pathway (KP) and combinatorial approaches with immunotherapies, as a promising strategy in cancer research. The key enzymes of the kynurenine pathway, such as IDO1, IDO2, and TDO, and metabolites like kynurenine, kynurenic acid, and quinolinic acid, are implicated in fostering an immunosuppressive tumor microenvironment and promoting glioma cell survival. In glioblastoma, a highly aggressive glioma subtype, elevated IDO and TDO expression correlates with reduced survival rates. KP metabolites, such as kynurenine (KYN), 3-hydroxykynurenine (3-HK), kynurenic acid (KYNA), and quinolinic acid (QUIN), are involved in modulating immune responses, oxidative stress, neuroprotection, and neurotoxicity. This review synthesizes recent findings on the kynurenine pathway involvement in glioma pathogenesis, examining potential therapeutic targets within this pathway and discussing ongoing clinical trials that draw attention to treatments based on this pathway. Furthermore, it highlights novel findings on the post-translational modifications of kynurenine pathway enzymes and their regulatory roles, presenting their potential as therapeutic targets in gliomas.

Implications of Kynurenine Pathway Metabolism for the Immune System, Hypothalamic-Pituitary-Adrenal Axis, and Neurotransmission in Alcohol Use Disorder

In recent years, there has been a marked increase in interest in the role of the kynurenine pathway (KP) in mechanisms associated with addictive behavior. Numerous reports implicate KP metabolism in influencing the immune system, hypothalamic-pituitary-adrenal (HPA) axis, and neurotransmission, which underlie the behavioral patterns characteristic of addiction. An in-depth analysis of the results of these new studies highlights interesting patterns of relationships, and approaching alcohol use disorder (AUD) from a broader neuroendocrine-immune system perspective may be crucial to better understanding this complex phenomenon. In this review, we provide an up-to-date summary of information indicating the relationship between AUD and the KP, both in terms of changes in the activity of this pathway and modulation of this pathway as a possible pharmacological approach for the treatment of AUD.