EBNA1-targeted probe for the imaging and growth inhibition of tumours associated with the Epstein–Barr virus

Abstract

Epstein-Barr nuclear antigen 1 (EBNA1), a dimeric oncoprotein of the Epstein-Barr virus (EBV), is essential for both viral-genome maintenance and the survival of infected cells. Despite EBNA1's potential as a therapeutic target, tools for the direct monitoring of EBNA1 in vitro and in vivo are lacking. Here, we show that a peptide-based inhibitor that luminesces when bound to EBNA1 inside the nucleus of EBV+ cells can regulate EBNA1 homodimer formation and selectively inhibit the growth of EBV+ tumours of nasopharyngeal carcinoma cells (C666-1 and NPC43) and Burkitt's lymphoma Raji cells. We also show that the peptide-based probe leads to 93% growth inhibition of EBV+ tumours in mice. Our findings support the hypothesis that selective inhibition of EBNA1 dimerization can be used to afford better EBV-related cancer differentiation, and highlight the potential application of the probe as a new generation of biotracers for investigating the fundamental biological function of EBNA1 and for exploring its application as a therapeutic target.