IDO1 Activity Predicts Lung Toxicity in Patients with Unresectable Stage III NSCLC and Chemoradiotherapy.

Objectives: Indoleamine 2,3-dioxygenase 1 (IDO1) acts as the key rate-limiting enzyme that converts tryptophan (Trp) to kynurenine (Kyn). Its activity was primarily induced by interferon-γ (IFN-γ), which was reported to play a role in the development of acute radiation-induced pneumonitis. In this study, we aimed to investigate the correlation between IDO1 activity and radiation-induced lung toxicity (RILT) in stage III nonsmall cell lung cancer (NSCLC) patients who were treated with chemoradiotherapy (CRT). Materials and Methods: Systemic IDO1 activity was reflected by Kyn : Trp ratio. Plasma levels of Kyn and Trp in 113 stage III NSCLC patients were measured by high-performance liquid chromatography (HPLC) before the initiation of radiotherapy. Dynamic change of IDO1 activity was followed in 23 patients before, during, and after radiotherapy. We also used RNA sequencing (RNA-seq) data from the Cancer Genome Atlas Program (TCGA) database and performed gene set enrichment analysis (GSEA) to explore how IDO1 was involved in the development of RILT. Results: 9.7% (11/113) of the whole group developed G3+ (greater than or equal to Grade 3) RILT. Preradiation IDO1 activity was significantly higher in patients who developed G3 + RILT than in nonG3 + RILT patients. (P = 0.029, AUC = 0.70). Univariate and multivariate analyses showed that high IDO1 activity was independently associated with the risk of G3 + RILT (P = 0.034). A predictive model combining both IDO1 activity and FEV1 was established for severe RILT and displayed a moderate predictive value (AUC = 0.83, P < 0.001). The incidence of G3 + RILT was 2.6% (1/38) in patients with an IDO activity ≤0.069 and FEV1 > 59.4%, and 50.0% (6/12) in those with an IDO activity >0.069 and FEV1 ≤ 59.4%. Of 23 patients with dynamic tracking, the IDO1 activity of postradiation was significantly lower than midradiation (P = 0.021), though no significant differences among the three time points were observed (P = 0.070). Bioinformatic analysis using RNA-seq data from 1014 NSCLC patients revealed that IDO mainly functioned in the inflammatory response instead of the late fibrosis process in NSCLC patients. Conclusion: High baseline IDO1 activity combined with unfavorable baseline FEV1 was predictive of severe RILT in unresectable stage III NSCLC patients. IDO1 might play a role in the acute inflammatory response. Finding effective interventions to alleviate RILT using IDO inhibitors is warranted in the future.

Dynamic change of IDO1 activity predicts survival in patients with unresectable stage III NSCLC and chemoradiotherapy.

Objective: High activity of Indoleamine 2,3-dioxygenase1 (IDO1) in lung cancer patients converts tryptophan (Trp), which is the essential amino acid for T-cell metabolism, to kynurenine (Kyn) and consequently suppresses anti-tumor immune responses. We aimed to track the dynamics of IDO1 activity in stage III non-small cell lung cancer (NSCLC) patients who received first-line radiotherapy (RT) and explore its association with survival outcomes. Materials and methods: Systemic IDO1 activity was calculated by Kyn : Trp ratio. Plasma levels of Kyn and Trp in 113 thoracic RT-received stage III NSCLC patients were measured by high-performance liquid chromatography before the initiation of RT. The dynamic change of IDO1 activity was followed in 24 patients by measuring the Kyn : Trp ratio before, during, and after RT administration. Results: In 24 patients with dynamic tracking of plasma IDO1 activity, there were no significant alterations observed among the three time points (Friedman test, p = 0.13). The changing pattern of the Kyn : Trp ratio was divided into four groups: decreased consistently during RT, first increased, then decreased, increased consistently, first decreased then increased. Patients whose Kyn : Trp ratio kept decreasing or first increased then decreased were defined as the good-change group. The good-change status was identified as an independent positive factor for overall survival (OS) and progression-free survival (PFS) (p = 0.04; p = 0.01) in multivariate analysis among evaluated parameters. Patients with good change showed significantly superior local control than the bad-change group (p = 0.01, HR = 0.22). In 113 stage III NSCLC patients with pre-radiation Kyn : Trp ratio, a trend that high baseline IDO1 activity was associated with short OS was observed (p = 0.079). Conclusion: Favorable change in IDO1 activity during RT was associated with superior OS, PFS, and local control. IDO1 activity is a promising biomarker for prognosis in stage III NSCLC patients.

Metabolomics and integrated network pharmacology analysis reveal that ginkgolides act as potential active anticancer components by regulating one-carbon metabolism.

ETHNOPHARMACOLOGICAL RELEVANCE: Ginkgo biloba L. is a rare tree species unique to China. Ginkgo biloba is a traditional Chinese medicinal with a long history, acting on the heart and lung meridians, and has been reported to have a significant effect on non-small cell lung cancer. However, the mechanism underlying this metabolic effect is poorly understood. AIM OF THE STUDY: To identify the active components of Ginkgo biloba extract that may have effects on non-small cell lung cancer and their mechanisms of metabolic regulation. MATERIALS AND METHODS: In this study, LC-MS/MS was used to investigate the chemical constituents of Ginkgo biloba extract. Network pharmacology was used to identify the active components potentially valuable in the treatment of non-small cell lung cancer. Antitumor activity was evaluated using CCK-8 and apoptosis assays. The mechanisms of metabolic regulation by the active components were further explored using untargeted metabolomics, targeted metabolomics, and western blot experiments. RESULTS: Network pharmacology and component analysis of Ginkgo biloba extract identified four ginkgolides that significantly affect non-small cell lung cancer. Their antiproliferative activity in A549 cells was evaluated using CCK-8 and apoptosis assays. The metabolomics results indicated that the ginkgolides had a significant regulatory effect on metabolic pathways related to one-carbon metabolisms, such as purine metabolism, glutathione metabolism, and the methionine cycle. Further targeted metabolomics analysis on one-carbon metabolism found that the ginkgolides may significantly affect the content of multiple metabolites in A549 cells, including purine, S-adenyl methionine, S-adenylyl homocysteine, and glutathione upregulated, and adenosine, tetrahydrofolate, and 10-Formyl-tetrahydrofolate significantly decreased. Notably, dihydrofolate reductase (DHFR) and methylenetetrahydrofolate dehydrogenases (MTHFR) were found to be altered after the treatment of ginkgolides. CONCLUSION: This in vitro study indicated that ginkgolides might inhibit the growth of A549 cells by targeting one-carbon metabolism. This study also demonstrated that metabolomics combined with network pharmacology is a powerful tool for identifying traditional Chinese medicines' active components and metabolic mechanisms.