Effect of Transforming Growth Factor-β1 on the Cell Growth and Epstein–Barr Virus Reactivation in EBV-Infected Epithelial Cell Lines

AbstractTransforming growth factor (TGF)-β1 is a multifunctional cytokine that plays important roles in regulating cell growth and differentiation in many biological systems. In this study, we found that gastric tissue-derived Epstein–Barr virus (EBV)-infected epithelial cell lines GT38 and GT39 had resistance to TGF-β1-mediated growth inhibition and apoptosis compared to a TGF-β1-susceptible gastric carcinoma cell line HSC-39. However, TGF-β1 partially induced EBV reactivation in GT38 and GT39 cells, as shown by the induction of EBV immediate-early BZLF1 RNA and its protein product ZEBRA and early antigen-D. The expressions of TGF-β receptor I and II were detected in GT38 and GT39 cells by Northern and Western blot analyses. Both cell lines spontaneously produced the TGF-β1, which was sufficient for inhibiting cell growth of HSC-39 cells. Taken together, these data suggest that TGF-β1 may be a key factor for EBV reactivation and selective growth of EBV-infected epithelial cells in vivo