Down-Regulation of GKN1 in Gastric Cancer Is Not Associated with the RUNX3 Expression

Abstract

Gastrokine 1 (GKN1) is a gastric mucosal protein highly expressed and secreted in normal individuals but during Helicobacter pylori infection or in gastric carcinogenesis it is strongly down-regulated or totally absent. In gastric cancer, the GKN1 gene is silenced through an epigenetic mechanism most likely mediated by a transcription factor that promotes on GKN1 promoter the activity of the enzymes SUV39H1 and HDACs. Because RUNX3 is a potential candidate in the regulation of molecular carcinogenesis process of stomach cancers, we tried to assess if RUNX3 could be involved in GKN1 down-regulation in GC. 17 paired of non-tumoral and tumoral surgical specimens from patients with gastric cancer were analyzed for GKN1 and RUNX3 by Western blotting and chromatin immunoprecipitation (Chip) assays. The overall results indicated that RUNX3 expression was not associated with the down-regulation of GKN1. The expression levels of RUNX3 in non-tumoral and tumoral samples suggest that RUNX3 does not act as a tumor suppressor but that it might play a complex oncogenic role in gastric cancer cells.

Association of H3K4me3 and CBX7 Levels to the Down-Regulation of <i>GKN</i>1 Gene Expression in Gastric Cancer Cells

“…Human gastric adenocarcinoma cell line (AGS) was grown in DMEM-F12 supplemented with heat-inactivated FBS, 1% penicillin/streptomycin and 1% L-glutamine at 37˚C in a 5% CO 2 atmosphere. Human GC tissues were from our collection of specimens as reported [17]. All patients were interviewed for their habit (alcohol intake, chronic use of drugs, smoking dependency).…”