Effect of yessotoxin on cytosolic calcium levels in human hepatocellular carcinoma cells in vitro

Abstract

Yessotoxin (YTX) and its analogs are a type of marine toxins found in marine environments in numerous coastal countries. These toxins tend to accumulate in filter-feeding molluscs and may threaten the shellfish industry and public health. Several previous studies indicated that YTX may induce apoptosis in different types of cell lines, although the exact underlying mechanisms have not yet been elucidated. The aim of this study was to mainly focus on the effect of YTX on cytosolic Ca(2+) levels in human hepatocellular carcinoma cells. In order to investigate the exact mechanism of YTX-evoked Ca(2+) increase, laser scanning confocal microscopy was used, with the addition of the chelator ethylene glycol tetraacetic acid (EGTA) and nifedipine, an L-type Ca(2+) channel blocker, to the reaction system. The results demonstrated that YTX caused cytosolic Ca(2+) level increase in Bel7402 cells and the YTX-evoked Ca(2+) increase was successfully blocked by EGTA and nifedipine. Therefore, our results indicated that YTX may cause apoptosis via inducing Ca(2+) entry in Bel7402 cells.