CHARACTERIZATION OF MACROMOLECULAR LIGNINS AS EPSTEIN-BARR-VIRUS INDUCER IN FOODSTUFF ASSOCIATED WITH NASOPHARYNGEAL CARCINOMA RISK

Epstein-Barr virus (EBV)-inducing activity was previously demonstrated to occur in various foodstuffs, including dried salted fish in southe rn China and 'harissa', a homemade spice mixture in Tunisia, whose con sumption is epidemiologically associated with an increased risk for de veloping nasopharyngeal carcinoma (NPC), For the isolation and the cha racterization of active ingredients in harissa, we used as a rapid scr eening assay the induction of the chloramphenicol acetyltransferase (C AT) activity through the EBV-DR promoter in DR-CAT Raji cells. After f ractionation of harissa and column chromatography on Sepharose-CL4B, t he major inducing activity was associated with a macromolecular fracti on which was chemically characterized as lignin-containing complexes, The active material enhanced EBV-DR induction with an activity compara ble to the tumor promoter and strong EBV inducer, 12-O-tetradecanoylph orbol-13-acetate, Experiments with inhibitors of protein kinase C-rela ted pathways suggested that the EBV-inducing activity of lignin fracti ons operates through a different pathway, Our results on the presence of specific lignin fractions in high-risk food items that can induce i mportant cellular functions linked to tumor promotion are discussed in relation to NPC genesis and etiology.