Abstract
In order to study the chemopreventive action of retinoid in patients with nasopharyngeal carcinoma (NPC), the effect of retinoid (polyprenoic acid derivative, E-5166) on expression of Epstein-Barr virus early antigen (EBV-EA) was examined in vitro. Epithelial hybrid cells (A2L/AH) derived from human nasopharynx were used as a model of NPC. The cells induced by n-butyric acid to EBV-EA synthesis were treated simultaneously with various concentrations of retinoid, and then we investigated the inhibitory effect of retinoid on EBV-EA induction by n-butyric acid. The percentage of EBV-EA positive cells was about 40% in those treated with n-butyric acid (4mM/ml), whereas that in the treated cells with n-butyric acid plus retinoid (E-5166, 5-10μg/ml) was 8.1 and 7.5% respectively. Similarly, the percentage of EBV-EA positive cells treated with n-butyric acid plus retinoid (5μg/ml) and human interferon (HuINF-β, 1000IU/ml) was 8.7%. There was no effect of HuINF-β to synthesize the inhibitory action of retinoid on EBV-EA induction by n-butyric acid.
