Novel Pyrrole–Imidazole Polyamide Hoechst Conjugate Suppresses Epstein–Barr Virus Replication and Virus-Positive Tumor Growth

Epstein–Barr virus (EBV) establishes latent infection and is associated with several types of lymphomas and carcinomas. EBV nuclear antigen 1 (EBNA1) is expressed in all EBV-positive tumor cells. EBNA1 binds to the origin of virus plasmid replication (OriP) on the EBV episome to initiate virus DNA replication and regulates virus gene expression as a transcriptional activator. In this study, we designed and synthesized a pyrrole–imidazole polyamide–Hoechst 33258 conjugate named EIP-2 (2), which specifically binds to the OriP region with high affinity, to interrupt EBNA1-OriP binding in vitro and in vivo. By eradicating the EBV episome in EBV-positive cells, compound 2 selectively inhibited EBV-positive cell proliferation. Moreover, the injection of 2 significantly suppressed tumor growth in the mice xenograft tumor model. These findings demonstrate that compound 2 is a potential therapeutic candidate for the treatment of EBV-associated tumors.