In mammals, several DNA repair pathways are responsible for removal of DNA lesions and thus ensure genomic stability. The base excision repair (BER) pathway is responsible for the removal of small base lesions resulting from deamination, oxidation, or methylation ; its action is known to reduce the cytotoxic effects of certain anticancer drugs. As a result, proteins involved in BER are increasingly considered as targets for cancer treatment. One of these, human Endonuclease III or hNTH1, a bifunctional DNA glycosylase, responsible for the removal of oxidized pyrimidines, has been shown to be regulated by the multifunctional Y-box binding protein 1 (YB1). Interestingly, YB1 is an established metastatic marker : high expression and nuclear localization of YB1 correlate with tumor aggressiveness, drug resistance and poor patient survival in various tumors. In this work, we used Förster Resonance Energy Transfer (FRET) and AlphaLISA technologies to characterize this interaction and define the minimal regions of hNTH1 and YB1 required for complex formation. This study led us to design an original and cost-effective genetically encoded FRET-based biosensor for the rapid in vitro high-throughput screening for potential inhibitors of the hNTH1-YB1 complex. Two pilot screens were carried out allowing the selection of several promising compounds. Of these, two bind to YB1 and partially resensitize drug-resistant breast tumor cells to the chemotherapeutic agent, cisplatin.
This work thus confirms the potential of the hNTH1-YB1 interface as a druggable target for the development of new therapeutic strategies for the treatment of drug-resistant tumors.
Senarisoy M, Barette C, Lacroix F, De Bonis S, Stelter M, Hans F, Kleman JP, Fauvarque M-O and Timmins J. A FRET-based biosensor for targeting the hNTH1-YB1 interface as a potential anti-cancer drug target. ACS Chemical Biology (2020) 15, 4, 990-1003. DOI : 10.1021/ acschembio.9b01023.