Novel telomere-targeting dual-pharmacophore dinucleotide prodrugs for anticancer therapy

Telomerase is an attractive therapeutic target due to its expression in most cancer cells. This study focuses on harnessing the potential of telomerase to alter telomeres as a therapeutic modality. We designed and synthesized divalent dinucleotide prodrugs comprised of 6-thio-2'-deoxyguanosine (6-thio-dG; THIO) and 5-fluoro-2'-deoxyuridine (5-FdU) nucleosides. Although dinucleotides containing 5-FdU pharmacophores showed better activity in vitro versus compounds containing only THIO pharmacophores, we observed greater activity for THIO-containing compounds in vivo. The homopurine compounds MAIA-2022-12 and MAIA-2021-20, with two 6-thio-dG pharmacophores, linked by 3', 5'- and 5', 5'-phosphodiester bonds, respectively, demonstrated the greatest anticancer efficacy among the compounds tested and induced host immune-memory responses in vivo. The sequential combination of MAIA-2022-12 or MAIA-2021-20 with the immune anti-PD-1 or anti-PD-L1 checkpoint inhibitors demonstrated superior anticancer efficacy compared with the corresponding monotherapies. We conclude that MAIA-2022-12 and MAIA-2021-20 are promising candidates for future preclinical and potential clinical studies.