Upregulation of TMEFF2 is involved in the antiproliferative effects of vitamin C and tyrphostin AG490 on GES‑1 and AGS cells

Transmembrane protein with epidermal growth factor (EGF)-like and two follistatin motifs 2 (TMEFF2) is downregulated in human gastric cancer, and its levels are associated with tumor aggressiveness. Herein, a positive correlation was identified between serum vitamin C levels (µg/ml) and mRNA levels of TMEFF2 in gastric cancer tissue. TMEFF2 silencing promotes cell proliferation in GES-1 normal human gastric epithelial cells and AGS human gastric adenocarcinoma cells. Notably, vitamin C and AG490 exerted antiproliferative effects on the two cell lines. The present study demonstrated that small interfering (si)-RNA-TMEFF2 exerts pro-proliferative effects on GES-1 and AGS cells. The results revealed that vitamin C significantly inhibited the growth of GES-1 and AGS cells by reducing cell viability, decreasing the expression of proliferating cell nuclear antigen (PCNA), and blocking the STAT3 pathway. Moreover, siRNA-TMEFF2-induced enhanced cell viability and PCNA expression were significantly reversed by additional vitamin C treatment; notably, markedly enhanced TMEFF2 expression was observed. Upregulated TMEFF2 expression was observed in association with the antiproliferative effect of AG490. In conclusion, serum vitamin C content (µg/ml) was positively correlated with the mRNA levels of TMEFF2 in gastric cancer tissue. Exploring novel drugs that target TMEFF2 is a potential therapeutic strategy for blocking human GC.