Induction of apoptosis in human peritoneal mesothelial cells by gastric cancer cell supernatant promotes peritoneal carcinomatosis

This study was carried out to evaluate the effects of gastric cancer cell supernatant on human peritoneal mesothelial cell viability and apoptosis and to investigate the mechanism of action of gastric cancer in a mesothelial cell line (HMrSV5). Cell viability was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazoliumbromide (MTT) assay. Mesothelial cells treated with gastric cancer cell supernatant were stained with acridine orange/ethidium bromide and subjected to fluorescence microscopy. C57BL/6 mice were used to establish a cancer invasion model. Morphological changes and exfoliation occurred, and naked areas appeared in both cultured mesothelial cells and the parietal peritoneum after treatment with gastric cancer cell supernatant. Cell supernatant from gastric cancer cells induced apoptosis of mesothelial cells in a time-dependent manner. Obvious morphological changes of cell apoptosis were detected, such as condensation of chromatin, nuclear fragmentations, and apoptotic ladders. These findings demonstrate that gastric cancer cells induce apoptosis of human peritoneal mesothelial cells through supernatants in early peritoneal metastasis.