Malignant neoplasm has developed through muultistep process, and premalignant lesions of oral mucosa are representative model of multistage carcinogenesis. Most of head and neck cancers including tumors of oral cavity are squamous cell carcinoma. Even though the development of therapeutic modatitis such as surgical techniques, chemotherapy, radiotllerapy have permitted survival period, death rate of head and neck carcinoma has not been improved. Because surgical intervention of head and neck lesion cause the tissue defect of facial skeleton, social adaptation of post-surgical patient is another problem. Therefore, chemoprevention which inhibit the tumor development from the premalignant lesion rather than treatment of cancer, has recently studied.
Diallyl sulfide is a major oil-soluble component of garlic, used for medicinal purposed for more than 3000 years. Recently, it has been demonstrated to possess chemopreventive effects during the multistage carcinogenesis of animal model. And several investigations have suggested that diallyl sulfide may also be effctive in the in vitro growth inhibition of canine mammary tumor cells, however its efect on the human carcinoma cells are not well srudied. Therefore, the purposes of this study was performed to evaluate the cytotoxic effect of diallyl suilfide to oral squamous cell carcinoma and the possibility of this agent for inhibit secondary and metastatic cancer of head and neck.
In this study, cytotoxic effects to oral squamous carcinoma cell lines were evaluated by diallyl sulfide which is major component of garlic, and biologic effect of this agent were evaluated by flow cytometric analysis. The results of this study are as follows ː
1. Growth of all of the oral cancer cell line were inhibited at the concentration of 2 mM diallyl sulfide, whereas 500 uM concentration could not inhibit the proliferation. The effect of diallyl sulfide was dose-and time-dependent.
2. The sensitivity of oral cancer cell lines to diallyl sufide were variable, and IC50 at 96 hours were 0.999-1.423 mM.
3. Nuclear fragmentation following 2 mM of diallyl sulfide were significantly increased after 24 hours. Although nuclear fragmentation of YD-17 that has relatively low sensitivity to diallyl sulfide also somewhat increased, the inhibitory effect of this agent was not significant.
4. S phase fraction of oral cancer cell lines following 2 mM diallyl sulfide were grearly decreased after 8 hours, and the fraction rate after 24 hours were decreased for 4 times.
These results suggest that diallyl sulfide has the effect of growth inhibition to oral cancer cell lines, and these effects result from the nuclear fragmentation induced apoptosis and inhibition of DNA synthesis. Therefore further study will be continued and focused to develop the agent of natural non-toxic compound for prevention of secondary cancer or metastatic lesion after surgical treatment of head and neck cancer.
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