Anti-invasive Activity of Ethanol Extracts of Ganoderma lucidum through Tightening of Tight Junctions and Inhibition of Matrix Metalloproteinase Activities in Human Gastric Carcinoma Cells

This study investigated the effect of ethanol extracts of Ganoderma lucidum (EGL) on the correlation between tightening of the tight junctions (TJs) and the anti-invasive activity in human gastric adenocarcinoma AGS cells to elucidate further the possible anticancer mechanisms that G lucidum exerts. Within the concentrations of EGL that were not cytotoxic, EGL markedly inhibited the cell motility and invasiveness in a concentration-dependent manner. The activities of matrix metalloproteinases (MMP)-2 and MMP-9 in AGS cells were dose-dependently inhibited by treatment with EGL, and this was correlated with a decrease in expression of their mRNA and proteins and the upregulation of the expression of the tissue inhibitors of metalloproteinases. The anti-invasive activity of EGL was also found to be associated with the increased tightness of the TJ, which was demonstrated by an increase in transepithelial electrical resistance. Additionally, EGL repressed the levels of the claudin family members, which are major components of TJs that play a key role in the control and selectivity of paracellular transport. Furthermore, the levels of E-cadherin, a type I transmembrane glycoprotein, were inhibited by EGL treatment, however, those of snail, an epithelial to mesenchymal transition regulator and zinc finger transcription factor, were concentration-dependently increased in response to EGL treatment. Although further studies are needed, the present study indicates that TJs and MMPs are crucial targets of EGL-induced anti-invasiveness in human gastric cancer AGS cells.