ATR激酶抑制剂通过诱导复制应激和增强基因毒性药物在妇科癌细胞中促进细胞杀伤。为了探索卵巢癌对ATRi的获得性抵抗机制，我们通过持续给予临床ATR抑制剂AZD6738进行剂量测定，产生了对ATRi抗药性的卵巢癌细胞。通过给予AZD6738进行剂量测定，产生了ATRi抗药性的卵巢癌细胞（OVCAR3和OV90），并评估其对Chk1i（LY2603618）、PARPi（奥拉帕尼）以及联合顺铂或CDK4/6抑制剂（帕博西尼）的敏感性。我们通过多种方法对模型进行了表征，包括在OV90细胞中沉默CDC25A并评估其对ATRi反应的影响。对ATRi抗药性OV90异种移植瘤的血清蛋白组分析用于鉴定ATRi抗药性的循环生物标志物候选者。 AZD6738抗药性细胞系对LY2603618具有耐药性，但对Olaparib或与顺铂的联合治疗没有耐药性。细胞周期分析显示ATRi抗药性细胞在AZD6738治疗后出现G1/S阻滞。相应地，与Palbociclib联合使用会导致对AZD6738的耐药性。AZD6738抗药细胞表现出G1/S期调控蛋白的丰度改变，包括AZD6738抗药性OV90细胞中CDC25A的丢失。在OV90细胞中沉默CDC25A可导致对AZD6738的耐药性。从AZD6738抗药性OV90异种移植瘤的血清蛋白组学分析中发现，维生素D结合蛋白（GC）、载脂蛋白E（APOE）和A1（APOA1）在AZD6738抗药背景中显著升高。 我们表明，通过持续给予AZD6738对卵巢癌细胞进行剂量测定可导致对ATR/Chk1抑制剂的耐药性，CDC25A表达的缺失代表了卵巢癌细胞对ATRi治疗的抵抗机制，并鉴定了CDC25A低表达，AZD6738抗药性卵巢癌细胞的几个循环生物标志物候选者。 版权所有 © 2023 Elsevier Inc. 保留所有权利。

ATR kinase inhibitors promote cell killing by inducing replication stress and through potentiation of genotoxic agents in gynecologic cancer cells. To explore mechanisms of acquired resistance to ATRi in ovarian cancer, we characterized ATRi-resistant ovarian cancer cells generated by metronomic dosing with the clinical ATR inhibitor AZD6738.ATRi-resistant ovarian cancer cells (OVCAR3 and OV90) were generated by dosing with AZD6738 and assessed for sensitivity to Chk1i (LY2603618), PARPi (Olaparib) and combination with cisplatin or a CDK4/6 inhibitor (Palbociclib). Models were characterized by diverse methods including silencing CDC25A in OV90 cells and assessing impact on ATRi response. Serum proteomic analysis of ATRi-resistant OV90 xenografts was performed to identify circulating biomarker candidates of ATRi-resistance.AZD6738-resistant cell lines are refractory to LY2603618, but not to Olaparib or combinations with cisplatin. Cell cycle analyses showed ATRi-resistant cells exhibit G1/S arrest following AZD6738 treatment. Accordingly, combination with Palbociclib confers resistance to AZD6738. AZD6738-resistant cells exhibit altered abundances of G1/S phase regulatory proteins, including loss of CDC25A in AZD6738-resistant OV90 cells. Silencing of CDC25A in OV90 cells confers resistance to AZD6738. Serum proteomics from AZD6738-resistant OV90 xenografts identified Vitamin D-Binding Protein (GC), Apolipoprotein E (APOE) and A1 (APOA1) as significantly elevated in AZD6738-resistant backgrounds.We show that metronomic dosing of ovarian cancer cells with AZD6738 results in resistance to ATR/ Chk1 inhibitors, that loss of CDC25A expression represents a mechanism of resistance to ATRi treatment in ovarian cancer cells and identify several circulating biomarker candidates of CDC25A low, AZD6738-resistant ovarian cancer cells.Copyright © 2023 Elsevier Inc. All rights reserved.