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Summary Extracts from sea urchin intestine were screened for new anti-tumour drugs. Four glycolipids, 3'-sulphonoquinovosyl-1', 2'-diacylglyceride (A-4), 3'-sulphonoquinovosyl-1 '-monoacylglyceride (2'-Iyso A-4, A-5), NeuGca2-6GIcP1-1 ceramide (A-6) and HSO3-8NeuGca2-6Glcp1-1ceramide (A-7), were isolated from the intestine of sea urchin, Strongylocentrotus intermedius, and characterized by means of proton nuclear magnetic resonance spectroscopy and fast atom bombardment mass spectrometry. When tested for cytotoxic activity against tumour cells in vitro, A-5 showed significant activity, but A-4, -6 and -7 did not. In addition, the hydrophilic derivatives of A-4 or -5 had no cytotoxicity. Furthermore, the anti-tumour effects on nude mice bearing solid tumours of a human lung adenocarcinoma cell line A-549 were evaluated in vivo using A-4 and -5. As a result, A-5 was found to be significantly effective in suppressing the growth of solid tumours, whereas A-4 had no effect. Pathologically, the solid tumours showed haemorrhagic necrosis areas after treatment with A-5. In this study, we have demonstrated the anti-tumour effect of sulphonoquinovosyl-lysoglyceride (A-5), which provides important information that this sulpholipid could be a useful drug for cancer chemotherapy.

An oral epithelial cell line derived from buccal mucosa squamous cell carcinoma, HO-1-N-1, was used to elucidate the role of epidermal growth factor (EGF) in saliva on wound healing of the oral mucosa. The effects of EGF on DNA synthesis, and cell migration was studied and the related signal transduction pathways examined. DNA synthesis by HO-1-N-1 cells was stimulated dose-dependently by 1-10 ng ml(-1) EGF, but significantly inhibited by addition of a PI3-K inhibitor (wortmannin), a p38 MAPK inhibitor (SB203580) or an MEKs inhibitor (PD98059). Cell migration was also accelerated by addition of 1-10 ng ml(-1) EGF; however, the migration rate was decreased to 30% by adding PD98059, to 40% by adding a tyrosine kinase inhibitor (herbimycin A), and to 60% by adding wortmannin or dexamethasone. These results indicate that the physiologic concentration of EGF in saliva may stimulate proliferation and migration of oral epithelial cells for wound healing, when the oral mucosa has been injured. Furthermore, this study revealed that EGF-stimulated signal transduction pathways for epithelial cell proliferation and cell migration are different.

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