Induction of Epstein-Barr virus antigens by tumor promoters for epidermal and nonepidermal tissues.

Fifteen established tumor promoters belonging to different chemical groups were tested for their ability to induce Epstein-Barr virus (EBV)-specific early antigens (EA) in EBV-genome-positive nonproducer Raji cells. Saccharin (a promoter in urinary bladder carcinogenesis), DDT (a promoter in liver carcinogenesis), anthralin and iodoacetic acid (promoters in skin carcinogenesis) gave a significant induction with a maximum of induced cells of 20% (8 mg/ml), 0.8% (20 micrograms/ml), 0.8% (100 ng/ml) and 0.7% (0.4 micrograms/ml), respectively. In addition, after combined application with a noninducing dose (0.2 ng/ml) of 12-O-tetradecanoyl-phorbol-13-acetate (TPA), seven additional tumor promoters induced 0.3-2.1% EA-positive cells two days after treatment. The results indicate that in addition to mouse skin tumor promoters such as diterpene esters, several compounds reported to possess tumor-promoting activity in other types of tissue induce EBV. The data suggest that EBV induction is an effect commonly exerted by this group of compounds which should be very useful in screening for environmental tumor promoters.