VALIDATION OF 2 TEST SYSTEMS FOR DETECTING TUMOR PROMOTERS AND EBV INDUCERS - COMPARATIVE RESPONSES OF SEVERAL AGENTS IN DR-CAT RAJI CELLS AND IN HUMAN GRANULOCYTES

The response to a number of agents has been compared in two short-term assays used for the detection of virus inducers and tumor promoters: (i) induction of the EBV-DR-promoter in Raji cells, as measured by DR- CAT induction (DR-CAT test) and (ii) induction of the oxidative burst in human PMN, as measured by chemiluminescence in the presence of lumi nol or lucigenin (CL test). In order to validate the two assays, we ha ve investigated the responses to 12-O-tetradecanoyl-phorbol-13-acetate (TPA), 1,2-dioctanoylglycerol (DAG), phospholipase C (PLC EC-3-1-4-30 ) and ionophore A23187, which are active in both systems; arachidonic acid, linoleic acid and NaCl were found active only in the CL test. St aurosporine (protein kinase inhibitor), tamoxifen (estrogen antagonist and protein kinase C inhibitor), forskolin (protein kinase A activato r), R59949 (diacylglycerol kinase inhibitor), curcumin and N-acetyl-L- cysteine (scavengers of reactive oxygen species) and NaCl acted as inh ibitors. A good concordance of the EC50 values of inducing substances was found between the two assays, except for A23187 and DAG, which wer e required at much higher concentrations in the DR-CAT test. The inhib ition patterns by the panel of inhibitors revealed similarities and di screpancies in the induction pathways between the two systems, providi ng information on their mode of action. The two assays, which compleme nt each other, were shown to detect a number of known or suspected EBV inducers or tumor promoters, and thus appear useful for screening of new compounds or mixtures as well as of potential antiviral and antipr omoting substances.