Junctional Adhesion Molecule-A Promotes Proliferation and Inhibits Apoptosis of Gastric Cancer

Background/Aims: Junctional adhesion molecules (JAMs) are known as integral constituents of cellular tight junctions. However, the functions of JAMS in Cancer tissues are controversial and the function of JAM-A in gastric cancer is unclear. Acordingly, we investigated the function of JAM-A in gastric epithelial and gastric cancer cell proliferation, invasion and apoptosis. Methodology: A normal rat gastric mucosa-derived cell line (RGM1), a rat gastric cancer-like cell line established from RGM1 (RGK1), and a human gastric cancer cell line (NCI-N87) were used in this study. To examine the expression of junctional proteins, immunoblotting and immunofluorescent staining were performed with specific antibodies (JAM-A, claudins, occludin and ZO-1). JAM-A was knocked down by small interfering RNA. Results: RGM1 and RGK1 expressed JAM-A, occludin and ZO-1 but not claudins. RGK1 were significantly more invasive than RGM1. JAM-A knockdown significantly decreased the proliferation and the invasion of RGK1 but not of RGM1. JAM-A knockdown significantly decreased the proliferation of NCI-N87 cells and significantly decreased expression of the anti-apoptotic protein Bcl-xL but not the expression of AKT or Mcl-1. Conclusions: JAM-A promotes proliferation and inhibits apoptosis of gastric cancer, suggesting that it has a pivotal role in gastric cancer progression.