Ataxia Telangiectasia and Rad3-related (ATR) checkpoint kinase inhibitors are in clinical trials. Here we explored the molecular pharmacology and therapeutic combination strategies of the oral ATR inhibitor M1774 (Tuvusertib) with DNA damaging agents (DDAs). As single agent, M1774 suppressed cancer cell viability at nanomolar concentrations, showing greater activity than ceralasertib and berzosertib, but less potency than gartisertib and elimusertib in the small-cell lung cancer H146, H82, and DMS114 cell lines. M1774 also efficiently blocked the activation of the ATR-CHK1 checkpoint pathway caused by replication stress induced by TOP1 inhibitors. Combination with non-toxic dose of M1774 enhanced TOP1 inhibitor-induced cancer cell death by enabling unscheduled replication upon replicative damage, thereby increasing genome instability. Tandem mass tag (TMT)-based quantitative proteomics uncovered that M1774, in the presence of DDA, forces the expression of proteins activating replication (CDC45) and G2/M-progression (PLK1 and CCNB1). In particular, the fork protection complex proteins (TIMELESS and TIPIN) were enriched. Low dose of M1774 was found highly synergistic with a broad spectrum of clinical DDAs including TOP1 inhibitors (SN-38/irinotecan, topotecan, exatecan, and exatecan), the TOP2 inhibitor etoposide, cisplatin, the RNA polymerase II inhibitor lurbinectedin, and the PARP inhibitor talazoparib in various models including cancer cell lines, patient-derived organoids, and mouse xenograft models. Furthermore, we demonstrate that M1774 reverses chemoresistance to anticancer DDAs in cancer cells lacking SLFN11 expression, suggesting that SLFN11 can be utilized for patient selection in upcoming clinical trials.

中文翻译：

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新型 ATR 抑制剂 M1774 诱导复制蛋白过度表达并与 DNA 靶向抗癌药物产生广泛协同作用

共济失调毛细血管扩张症和 Rad3 相关 (ATR) 检查点激酶抑制剂正在进行临床试验。在这里，我们探讨了口服 ATR 抑制剂 M1774 (Tuvusertib) 与 DNA 损伤剂 (DDA) 的分子药理学和治疗组合策略。作为单药，M1774 在纳摩尔浓度下抑制癌细胞活力，在小细胞肺癌 H146、H82 和 DMS114 细胞系中显示出比 ceralasertib 和 berzosertib 更高的活性，但效力低于 gartisertib 和 elimusertib。M1774 还有效阻断了 TOP1 抑制剂诱导的复制应激引起的 ATR-CHK1 检查点通路的激活。与无毒剂量的 M1774 组合，通过在复制损伤时实现非计划复制，增强 TOP1 抑制剂诱导的癌细胞死亡，从而增加基因组不稳定性。基于串联质量标签 (TMT) 的定量蛋白质组学发现，在 DDA 存在的情况下，M1774 会强制表达激活复制 (CDC45) 和 G2/M 进展（PLK1 和 CCNB1）的蛋白质。特别是，叉保护复合蛋白（TIMELESS 和 TIPIN）得到了富集。低剂量的 M1774 与多种临床 DDA 具有高度协同作用，包括 TOP1 抑制剂（SN-38/伊立替康、托泊替康、exatecan 和 exatecan）、TOP2 抑制剂依托泊苷、顺铂、RNA 聚合酶 II 抑制剂 lurbinectedin 和 PARP抑制剂talazoparib在各种模型中的应用，包括癌细胞系、患者来源的类器官和小鼠异种移植模型。此外，我们证明 M1774 可以逆转缺乏 SLFN11 表达的癌细胞对抗癌 DDA 的化疗耐药性，这表明 SLFN11 可用于即将进行的临床试验中的患者选择。