3,9-Di-O-Methylnissolin Inhibits Gastric Cancer Progression by the RIPK2-Mediated Suppression of the NF-κB Pathway

Gastric cancer (GC) is a prevalent cause of death. 3,9-Di-O-methylnissolin (DOM) is a flavonoid isolated from Astragalus membranaceus. It has anticancer and anti-inflammatory effects, but its effect and mechanism of action on GC are not very clear.

The appropriate concentration was selected after observing the effects of varying concentrations of DOM on the viability of GC cells, which was examined through the cell counting kit-8 (CCK-8) assay. The receptor-interacting protein kinase 2 (RIPK2) overexpression plasmid was transfected into GC cells, which were then treated with DOM. Cell cycle and proliferation, RIPK2 levels, and inflammatory factor levels were evaluated by flow cytometry, cell colony formation assay, Hoechst 33,258 fluorescence, 5-ethynyl-2^′-deoxyuridine (EdU) assay, Transwell assay, immunofluorescence, and enzyme-linked immunosorbent assay (ELISA), respectively. The nuclear factor kappa-B (NF-κB) pathway was detected using immunofluorescence and Western blot.

The appropriate concentrations of DOM were found to be 200, 400, and 800 μg/mL. At these concentrations, in GC cells, DOM could significantly reduce EdU-positive cells; decrease the colony formation, migration, and invasion rates; block the cell cycle; increase the Hoechst 33,258 fluorescence intensity and apoptosis rate; and significantly reduce p-IκBα and p-NF-κB p65 expressions. Moreover, DOM notably reduced the high level of RIPK2. After the overexpression of RIPK2, these effects were significantly reversed in GC cells, and interleukin (IL)-1β and IL-6 contents were clearly elevated.

DOM can suppress the level of RIPK2 and inhibit the activation of the NF-κB signaling, thereby reducing inflammation; inhibiting the malignant progression of GC cells; and promoting cycle arrest.