Correlation between nutritional status and expression of intestinal dipeptide transporter 1 protein in gastric cancer patients

Abstract

Objective To study the expression of intestinal dipeptide transporter 1(PEPT1) protein in gastric cancer patients at different nutritional status, and to explore the possible regulatory mechanism. Methods According to Nutritional Risk Screening 2002 (NRS 2002) score, a total of 60 gastric cancer patients were divided into nutritional risk group (NRS 2002 score ≥ 3, n=18) and non-nutritional risk group (NRS 2002 score <3, n=42). With specimens of the small intestinal mucosa taken during operation, the expression of intestinal PEPT1 protein was detected using Western blot. The serum concentration of tumor necrosis factor (TNF-α) were measured using enzyme-linked immunosorbent assay. The expression of PEPT1 in Caco-2 cells treated with different concentrations of TNF-α (20, 50, 100 μg/L) were detected using Western blot at different time points (24, 48, 72 hours). Results The expression of intestinal PEPT1 (0.63 vs. 0.23, P=0.000) and serum TNF-α concentration (0.23 μg/L vs. 0.17 μg/L, P=0.001) in the nutritional risk group were significantly higher than those in the non-nutritional risk group. In Caco-2 cells, those treated with different concentrations of TNF-α (20, 50, 100 μg/L) for 24 hours had significantly higher PEPT1 expression than the blank group did (0.68 vs. 0.54, P=0.005; 0.72 vs. 0.54, P=0.001; 0.78 vs. 0.54, P=0.000). The Caco-2 cells treated with 50 μg/L TNF-α for 24, 48, and 72 hours had significantly higher PEPT1 expression compared with the cells in the blank group (0.57 vs. 0.52, P=0.004; 0.75 vs. 0.52, P=0.000; 0.77 vs. 0.52, P=0.000). Conclusion The expression of intestinal PEPT1 protein was increased in gastric cancer patients with nutritional risk, which was probably attributed to the regulation of TNF-α. Key words: Dipeptide transporter 1; Tumor necrosis factor; Gastric cancer; Nutritional Risk Screening 2002