Inhibition of proliferation and induction of apoptosis in SNU-1 human gastric cancer cells by the plant sulfolipid, sulfoquinovosyldiacylglycerol

The sulfoglycolipid sulfoquinovosyldiacylglycerol is present in the membranes of photosynthetic organisms. This sulfolipid reportedly has pharmaceutical potential as an antiviral and antitumor agent, although no studies have examined these properties of the sulfolipids that are consumed in plant foods. This study examined the biological effects of sulfoquinovosyldiacylglycerol on the human gastric cancer cell line SNU-1. SNU-1 cells were grown in the absence and of presence of 1 &mgr;M, 100 &mgr;M or 1 mM sulfoquinovosyldiacylglycerol for up to 72 hours. Cell proliferation and viability were determined. The cells were analyzed for nuclear morphological changes by fluorescence microscopy and for DNAase-mediated DNA cleavage by flow cytometry and TUNEL detection. As indicated by cell number, the proliferation of SNU-1 cells by 72 hours of culture in the presence of 100 &mgr;M and 1 mM SQDG was inhibited 24 and 100%, respectively, as compared with the number of SNU-1 cells cultured in the absence of SQDG. Inhibition of cell proliferation by 100 &mgr;M sulfoquinovosyldiacylglycerol was in part associated with apoptotic cell death, as shown by changes in nuclear morphology and DNA fragmentation, whereas incubation of cells with 1 mM sulfoquinovosyldiacylglycerol caused necrotic cell death. Treatment of SNU-1 cells with sulfoquinovosyldiacylglycerol did not result in cell cycle arrest. The antiproliferative and apoptotic effects of sulfoquinovosyldiacylglycerol on SNU-1 gastric cancer cells revealed in this study suggest that this common dietary sulfolipid has intriguing potential as a chemopreventive or chemotherapeutic agent.