Cellular Regulation of Kynurenic Acid-Induced Cell Apoptosis Pathways in AGS Cells

Abstract

Kynurenic acid was included in the three compounds (caffeic acid, chlorogenic acid, and kynurenic acid) that showed high antioxidant and anti-inflammatory potential among the phenolic compounds contained in Gynura procumbens. In this study, the mechanism of cancer cell death induced by kynurenic acid (KYNA), which has the highest molecular binding affinity, in the gastric cancer cell line AGS was confirmed in molecular docking analysis. KYNA showed the most cancer cell death effect on AGS cells among several gastric cancer cell lines (MKN, AGS, and SNU). AGS cells were used for later experiments, and KYNA concentrations of 0, 150, 200, and 250 µM were used. KYNA inhibited cell migration and proliferation in AGS cells in a concentration-dependent manner. G2/M phase cell cycle arrest and reduction of related proteins (Cdc25C, CDK1 and CyclinB1) were confirmed in KYNA-treated AGS cells. Apoptosis of KYNA-treated AGS cells was confirmed by Annexin V/propidium iodide (PI) staining flow cytometry analysis. As a result of morphological chromatin condensation through DAPI (4′,6-diamidino-2-phenylindole), intense blue fluorescence was confirmed. The mechanism of apoptosis induction of KYNA-treated AGS cells was confirmed by western blotting. In the extrinsic pathway, apoptosis induction markers FasL, Fas, and Caspase-3 and -8 were increased in a concentration-dependent manner upon KYNA treatment. In the intrinsic pathway, the expression of anti-apoptotic factors PI3K, AKT, and Bcl-xL was down-regulated, and the expression of apoptosis-inducing factors BAD, Bak, Bax, Cytochrom C, and Caspase-9 was up-regulated. Therefore, in the present study, we strongly imply that KYNA induces apoptosis in AGS gastric cancer cells. This suggests that KYNA, a natural compound, could be the basis for drug for the treatment of gastric cancer.

Identification of Kynurenic Acid-Induced Apoptotic Biomarkers in Gastric Cancer-Derived AGS Cells through Next-Generation Transcriptome Sequencing Analysis

“…It was confirmed in a previous study [ 24 ] that KYNA treatment induces tumor cell death in AGS cells. A total of 278 DEGs (log 2 (Fold Change) > 1.0 and p -value < 0.05) were identified in the KYNA treatment group, of which 120 up-regulated genes and 158 down-regulated genes were identified ( Table 1 ).…”

“…It has been demonstrated that KYNA has a direct effect on the gastric wall to prevent gastric ulcers [ 34 ]. In a previous study, KYNA was confirmed to induce apoptosis in gastric cancer-derived AGS cells [ 24 ]. In this study, it was confirmed that KYNA inhibits the growth and proliferation of cancer cells through the identification of biomarkers.…”