ABSTRACT
BACKGROUND AND OBJECTIVES: To examine the chemopreventive effects of Ginkgo biloba extract (EGb 761) on oral cavity cancer, we investigated the apoptosis of oral cavity cancer cells by EGb 761 and the apoptotic pathway involved. MATERIALS AND METHOD: SCC 1483 cancer cell line derived from a human retromolar trigone carcinoma was used. Inhibition of proliferation was examined by proliferation assay. Apoptosis was measured and confirmed by flow cytometry, DNA fragmentation assay and Western blotting with PARP antibodies. The involvement of the caspase cascade was investigated by co-treating with the caspase inhibitor, z-VAD-fmk. RESULTS: The inhibition of SCC 1483 cells was noted from 250 microgram/ml of EGb 761. Apoptosis was observed after 24 hours of incubation with 250 microgram/ml EGb 761 and it occurred in a time-dependent manner. Apoptosis was confirmed by DNA fragmentation and PARP cleavage. Co-treatment with z-VAD-fmk inhibited apoptosis and PARP cleavage by EGb 761. CONCLUSIONS: EGb 761 induces the apoptosis of SCC 1483 cells and the caspase cascade is involved in this apoptosis. Therefore, EGb 761 may be used as a chemopreventive agent in oral cavity cancer. Further studies are required on the clinical use of EGb 761.