Differential cytotoxicity of tumour promoter TPA for EBV-negative human lymphoma cell lines and their EBV-converted sublines

Abstract

The tumour-promoting phorbol diester 12-O-tetradecanoyl-phorbol-13-acetate (TPA) is toxic at nanomolar concentrations for Epstein-Barr virus (EBV)-negative human lymphoma cell lines BJAB and Ramos. Sublines that have been converted to Epstein-Barr nuclear antigen (EBNA)-positivity by infection with EBV survive and grow in TPA concentrations that are lethal for their non-converted parental lines. Resistance to the growth-inhibiting effect of TPA is higher in sublines of BJAB and Ramos that have been converted by the transforming B95-8 strain of EBV than in those converted by the non-transforming P3-HRI strain. The loss of TPA-sensitivity may reflect a change in the transformation or differentiation state of lymphoma cells as a result of EBV-conversion.