The synergy between alkylating agents and ERCC1-XPF inhibitors is p53 dependent.

Background: DNA repair plays a major role in maintaining genomic stability, thus limiting the transformation of normal cells into cancer cells. However, in cancer patients treated with DNA-targeting drugs, DNA repair can decrease efficacy by removing the damage generated by such molecules that is needed to induce pharmacological activity. Inhibiting DNA repair thus represents an interesting approach to potentiating the activity of chemotherapy in this setting.

Objectives: Here, we continue the characterization of an inhibitor of the interaction between Excision Repair Cross-Complementing Rrodent repair deficiency complementation group 1 (ERCC1) and Xeroderma Pigmentousum group F (XPF) (B9), two key proteins of nucleotide excision repair.

Methods: We used various cell lines and co-incubation studies for the determination of cell survival and DNA repair capacities.

Results: We show that it is synergistic with other platinum derivatives than previously described, and that synergy is lacking in cells not expressing ERCC1 or XPF. Finally, a series of experiments show that potentiation is observed only in cells expressing wild-type p53.

Conclusion: Our results confirm the mechanism of action of our ERCC1-XPF inhibitor and give important additional data on this approach to enhance the activity of already existing cancer drugs.