Department of Gynecologic Oncology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, China; Zhejiang Key Laboratory of Precision Diagnosis and Therapy for Major Gynecological Diseases, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, China; Zhejiang Provincial Clinical Research Center for Obstetrics and Gynecology, Hangzhou, China; Zhejiang Provincial Key Laboratory of Traditional Chinese Medicine for Reproductive Health Research, Hangzhou, China.
Department of Gynecology, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
Drug Resist Updat. 2024 Nov;77:101151. doi: 10.1016/j.drup.2024.101151. Epub 2024 Sep 12.
Ovarian cancer is the most lethal gynecological cancer and presents significant therapeutic challenges. The discovery of synthetic lethality between PARP inhibitors (PARPi) and homologous recombination deficiency marked a new era in treating BRCA1/2-mutated tumors. However, PARPi resistance remains a major clinical challenge.
RNA sequencing was used to identify genes altered by PARPi treatment and LC-MS was used to detect proteins interacting with CYP1B1. Resistance mechanisms were explored through ATAC-seq and gene expression manipulation. Additional techniques, including micrococcal nuclease digestion assays, DAPI staining, and fluorescence microscopy, were used to assess changes in nuclear morphology and chromatin accessibility.
The gradual exposure of Olaparib has developed a PARPi-resistant cell line, A2780-OlaR, which exhibits significant upregulation of CYP1B1 at both RNA and protein levels. Down-regulating CYP1B1 expression or using specific inhibitors decreased the cellular response to Olaparib. Linker histone H1.4 was identified as associated with CYP1B1. ATAC-seq showed differential chromatin accessibility between A2780-OlaR and parental cells, indicating that the downregulation of H1.4 was associated with increased chromatin accessibility and higher cell viability after Olaparib treatment.
Our findings reveal a novel role for CYP1B1 in driving PARPi resistance through distinct molecular mechanisms in A2780-OlaR. This study highlights the importance of chromatin accessibility in PARPi efficacy and suggests the CYP1B1/H1.4 axis as a promising therapeutic target for overcoming drug resistance in ovarian cancer, offering potentially therapeutic benefits.
卵巢癌是最致命的妇科癌症，治疗极具挑战性。PARP 抑制剂（PARPi）与同源重组缺陷之间的合成致死性的发现标志着治疗 BRCA1/2 突变肿瘤的新时代的到来。然而，PARPi 耐药仍然是一个主要的临床挑战。
使用 RNA 测序鉴定受 PARPi 治疗影响的基因，使用 LC-MS 检测与 CYP1B1 相互作用的蛋白质。通过 ATAC-seq 和基因表达操作来探索耐药机制。还使用微球菌核酸酶消化测定、DAPI 染色和荧光显微镜等其他技术来评估核形态和染色质可及性的变化。
逐渐暴露于奥拉帕利（Olaparib）会产生 PARPi 耐药细胞系 A2780-OlaR，该细胞系在 RNA 和蛋白质水平上均显著上调 CYP1B1。下调 CYP1B1 表达或使用特异性抑制剂可降低细胞对奥拉帕利的反应。连接组蛋白 H1.4 被鉴定为与 CYP1B1 相关。ATAC-seq 显示 A2780-OlaR 与亲本细胞之间的染色质可及性存在差异，表明 H1.4 的下调与奥拉帕利治疗后染色质可及性增加和细胞活力提高有关。
我们的研究结果揭示了 CYP1B1 在 A2780-OlaR 中通过不同的分子机制驱动 PARPi 耐药的新作用。这项研究强调了染色质可及性在 PARPi 疗效中的重要性，并表明 CYP1B1/H1.4 轴作为克服卵巢癌药物耐药性的有前途的治疗靶点具有潜在的治疗益处。
