Inhibition of DNA repair enzymes is an attractive target for increasing the efficacy of DNA damaging chemotherapies. The ERCC1-XPF heterodimer is a key endonuclease in numerous single and double strand break repair processes, and inhibition of the heterodimerization has previously been shown to sensitize cancer cells to DNA damage. In this work, the previously reported ERCC1-XPF inhibitor 4 was used as the starting point for an in silico study of further modifications of the piperazine side-chain. A selection of the best scoring hits from the in silico screen were synthesized using a late stage functionalization strategy which should allow for further iterations of this class of inhibitors to be readily synthesized. Of the synthesized compounds, compound 6 performed the best in the in vitro fluorescence based endonuclease assay. The success of compound 6 in inhibiting ERCC1-XPF endonuclease activity in vitro translated well to cell-based assays investigating the inhibition of nucleotide excision repair and disruption of heterodimerization. Subsequently compound 6 was shown to sensitize HCT-116 cancer cells to treatment with UVC, cyclophosphamide, and ionizing radiation. This work serves as an important step towards the synergistic use of DNA repair inhibitors with chemotherapeutic drugs.
抑制DNA修复酶是增强DNA损伤化疗药物疗效的有吸引力的目标。ERCC1-XPF异二聚体是许多单链和双链断裂修复过程中的关键内切酶,抑制异二聚化已被证明能增强癌细胞对DNA损伤的敏感性。在这项工作中,先前报道的ERCC1-XPF抑制剂4被用作对哌嗪侧链进一步修饰的in silico研究的起点。从in silico筛选中得分最高的化合物中选择了一些,采用后期功能化策略合成这些化合物,这种策略应该可以方便地合成这类抑制剂的进一步迭代。在合成的化合物中,化合物6在in vitro荧光内切酶测定中表现最佳。化合物6成功抑制了ERCC1-XPF内切酶活性in vitro,并在细胞实验中研究了核苷酸切除修复和异二聚化抑制。随后,化合物6被证明能增强HCT-116癌细胞对UVC、环磷酰胺和电离辐射的治疗敏感性。这项工作是朝着DNA修复抑制剂与化疗药物协同使用的重要一步。