Quercetin inhibits gastric cancer cell proliferation and migration and is associated with the suppression of the IDO1-Kynurenine-AhR axis.

OBJECTIVE

This study aimed to evaluate the effects of quercetin, paclitaxel, and cisplatin on the proliferation and migration of gastric cancer (GC) cells, focusing on the involvement of indoleamine 2,3-dioxygenase 1 (IDO1)-mediated tryptophan metabolism.

METHODS

Human GC cell lines (AGS and MKN-45) were cultured and treated with quercetin, paclitaxel, or cisplatin for 24 h according to experimental group assignments. Following treatment, cell viability was assessed using the CCK-8 assay. Apoptosis and cell cycle distribution were analyzed by flow cytometry. Cell invasion was evaluated using the Transwell assay, and migration was assessed using the wound healing assay. Quantitative PCR (qPCR) was performed to determine mRNA expression levels of IDO1, tryptophan 2,3-dioxygenase (TDO), kynurenine 3-monooxygenase (KMO), and aromatic hydrocarbon receptor (AhR). Western blotting was used to quantify protein expression of IDO1, IDO2, TDO, KMO, and AhR.

RESULTS

Treatment with quercetin, paclitaxel, or cisplatin significantly reduced cell viability, invasion, and migration, while increasing apoptosis in AGS and MKN-45 cells. These treatments were also associated with the downregulation of IDO1, IDO2, TDO, KMO, and AhR.

CONCLUSION

Quercetin, paclitaxel, and cisplatin exert anti-proliferative and anti-migratory effects on GC cells, potentially associated with the suppression of IDO1-mediated tryptophan metabolism.