摘要
背景：以奥沙利铂为基础的化疗是结直肠癌（CRC）的一线治疗方法。然而，奥沙利铂耐药性仍然是导致治疗失败和预后不良的主要挑战。DNA 损伤修复能力的增强是奥沙利铂耐药的一个关键机制。虽然XPA结合蛋白2（XAB2）与多种DNA损伤修复机制有关，但它在介导奥沙利铂耐药性方面的具体作用仍不清楚：方法：通过分析公共数据集确定了 XAB2。方法：通过分析公共数据集确定了 XAB2，并通过 Western 印迹分析和免疫组化评估 XAB2 的表达，同时进行生存分析以评估其在 CRC 中的临床意义。然后进行了功能实验，以评估 XAB2 对 CRC 的增殖、DNA 损伤修复和奥沙利铂耐药性的影响。研究人员使用 RNA 测序（RNA-seq）和染色质免疫共沉淀测序（ChIP-seq）来鉴定 XAB2 的靶基因。共免疫沉淀（Co-IP）和质谱法用于鉴定与XAB2相互作用的蛋白质。双荧光素酶报告实验、ChIP-qPCR、Co-IP、泛素化位点质谱和泛素检测被用来分析XAB2、Annexin A2（ANXA2）和泛素特异性蛋白酶10（USP10）之间的相互作用和潜在机制：结果：发现 XAB2 在 CRC 中表达，并与 CRC 患者的不良预后有关。XAB2 能促进 CRC 细胞增殖，并通过促进 DNA 损伤修复增强奥沙利铂耐药性。从机理上讲，接受奥沙利铂治疗的 CRC 细胞表现出 USP10 核表达增加。USP10 与 XAB2 结合，并在 K593 处去泛素化 XAB2 K48 链接的多泛素，从而通过减少泛素-蛋白酶体途径的降解稳定 XAB2。XAB2通过与ANXA2启动子结合，在转录水平上调ANXA2的表达，从而促进DNA损伤修复，减轻奥沙利铂诱导的DNA损伤，增强奥沙利铂抗性：总之，本研究证明 USP10/XAB2/ANXA2 轴促进了 CRC 的增殖、DNA 损伤修复和奥沙利铂耐药性。这些发现揭示了奥沙利铂在 CRC 中耐药的新机制，并为提高奥沙利铂在 CRC 治疗中的疗效提出了潜在的治疗靶点。Background: Oxaliplatin-based chemotherapy is the first-line treatment for colorectal cancer (CRC). However, oxaliplatin resistance remains a major challenge contributing to treatment failure and poor prognosis. An increased capacity for DNA damage repair is a key mechanism underlying oxaliplatin resistance. Although XPA binding protein 2 (XAB2) is implicated in various DNA damage repair mechanisms, its specific role in mediating oxaliplatin resistance remains unclear.
Methods: XAB2 was identified through analysis of public datasets. Western blot analysis and immunohistochemistry were performed to evaluate XAB2 expression, while survival analysis was performed to assess its clinical significance in CRC. Functional experiments were then conducted to assess the impact of XAB2 on proliferation, DNA damage repair, and oxaliplatin resistance in CRC. RNA sequencing (RNA-seq) and Chromatin immunoprecipitation-sequencing (ChIP-seq) were used to identify XAB2 target genes. Co-immunoprecipitation (Co-IP) and mass spectrometry were used to identify the proteins interacting with XAB2. Dual-luciferase reporter assays, ChIP-qPCR, Co-IP, ubiquitination site mass spectrometry, and ubiquitin assays were used to analyse the interactions and potential mechanisms involving XAB2, Annexin A2 (ANXA2), and ubiquitin-specific protease 10 (USP10).
Results: XAB2 was found to be expressed in CRC and was associated with poor prognosis in patients with CRC. XAB2 promoted CRC cell proliferation and enhanced oxaliplatin resistance by promoting DNA damage repair. Mechanistically, CRC cells treated with oxaliplatin exhibited increased USP10 nuclear expression. USP10 bound to XAB2 and deubiquitinated XAB2 K48-linked polyubiquitination at K593, thereby stabilising XAB2 by reducing its degradation via the ubiquitin-proteasome pathway. XAB2 upregulates ANXA2 expression at the transcriptional level by binding to the ANXA2 promoter, thereby promoting DNA damage repair, mitigating oxaliplatin-induced DNA damage, and enhancing oxaliplatin resistance.
Conclusions: In summary, this study demonstrates that the USP10/XAB2/ANXA2 axis promotes proliferation, DNA damage repair, and oxaliplatin resistance in CRC. These findings uncover a novel mechanism of oxaliplatin resistance in CRC and suggest potential therapeutic targets for improving the efficacy of oxaliplatin in CRC treatment.
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