A short-term in vitro assay for anti-tumor promoters, chemopreventive agents using human lymphoblastoid cells latently infected Epstein-Barr virus.

A51

The idea that neoplastic development consists of at least twoqualitatively different stages has gained general acceptance.The second, promotion stage has been suggested to be morecritical in the development of human cancer that the first,initation stage. Most tumor promoters do not bind DNA and are negative in the Ames mutagenicity assay, whereas initating carcinogensis usually meet one or both of these criteria.Recently, TPA, only those other phorbol esters with tumor promoting activity and fatty acid, n-butyric acid have been found to induced the viral cyclein latently infected Epstein-Barr Virus(EBV) genome carrying cells. We have suggested that a system consisting of EBV nonproducer Raji cells and each concentration of anti-tumor promoters, chemopreventive agents might be useful as a practical screening method of certain type of chemopreventive agents, anti-tumor promoters in our eatable and herbal plants. Interestingly, EBV-early antigen(EBV-EA) activation induced by TPA, can be diminished by the addition of chemopreventive agents, Tabebuia avellanedae (Brazilian herbal medicine), food colorants and vitamins to adequate culture medium. In this studies, we tried to arrange the screening and detection of chemopreventive agents for short term.