Epstein-Barr virus and telomerase: from cell immortalization to therapy

Abstract

Overcoming cellular senescence is strictly required for virus-driven tumors, including those associated with Epstein-Barr virus (EBV). This critical step is successfully accomplished by EBV through TERT expression and telomerase activation in infected cells. We herein review the complex interplay between EBV and TERT/telomerase in EBV-driven tumorigenesis. Evidence accumulated so far clearly indicates that elucidation of this issue may offer promising opportunities for the design of innovative treatment modalities for EBV-associated malignancies. Indeed, several therapeutic strategies for telomerase inhibition have been developed and are being investigated in clinical trials. In this respect, our recent finding that TERT inhibition sensitizes EBV+ lymphoma cells to antivirals through activation of EBV lytic replication is particularly promising and provides a rationale for the activation of clinical studies aimed at assessing the effects of combination therapies with TERT inhibitors and antivirals for the treatment of EBV-associated malignancies.

Figure 1

TERT inhibition induces EBV lytic cycle. In EBV-infected B cells, TERT up-regulates the expression of BATF, a negative regulator of BZLF1, thus preserving EBV latency. Following TERT inhibition, BATF level significantly decreases; the expression of BZLF1 leads to the induction of lytic proteins and a complete EBV lytic cycle.