Extrachromosomal circular DNA expressing miRNA promotes ovarian cancer progression

IF 6.8 1区医学 Q1 MEDICINE, RESEARCH & EXPERIMENTAL

Clinical and Translational Medicine Pub Date : 2025-09-23 DOI:10.1002/ctm2.70445

Ning Wu, Ling Wei, Qiyu Liu, Tianhui He, Cuiyu Huang, Yunpeng Jiang, Kailong Li, Hongyan Guo, Fengbiao Mao, Xiaolu Zhao

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引用次数: 0

Abstract

Background

Extrachromosomal circular DNA (eccDNA) has emerged as a critical driver of oncogenesis, yet its functional roles in high-grade serous ovarian cancer (HGSOC) remain poorly characterized. This highlights the need for comprehensive investigations into the abundance, biogenesis, and functional implications of eccDNA in HGSOC.

Methods

To characterize eccDNA in HGSOC, we performed comprehensive Circle-seq analysis to assess eccDNA abundance and genomic annotation in HGSOC tissues compared to normal ovarian tissue. For mechanistic validation of eccDNA biogenesis pathways, targeted knockdown experiments of microhomology-mediated end-joining (MMEJ) dependent on LIG3 and POLQ were conducted. Functional characterization of HGSOC-specific eccDNA-harboring precursor microRNAs (eccMIRs) included in vitro assays using HGSOC cells and in vivo tumor growth experiments.

Results

Circle-seq analysis revealed a 13-fold increase in eccDNA abundance in HGSOC compared to normal ovarian tissue, with significant enrichment in promoter and coding regions. The MMEJ pathway was identified as the predominant pathway for eccDNA biogenesis in HGSOC, supported by characteristic microhomologies at junction sites and validation via LIG3 and POLQ knockdown experiments. Notably, HGSOC-specific eccDNA frequently contained functional eccMIRs (eccMIR3661, eccMIR618, and eccMIR2277), which generate oncogenic miRNAs. These miRNAs promote tumor progression by downregulating tumor suppressor genes and activating key oncogenic pathways. Functional assays confirmed that these eccMIRs significantly enhanced HGSOC cell proliferation, migration, and invasion in vitro and promoted tumor growth in vivo.

Conclusions

These results underscore eccDNA as an oncogenic driver in HGSOC through non-coding RNA-mediated regulatory mechanisms, revealing novel therapeutic opportunities for targeting eccDNA biogenesis in this aggressive malignancy.

Key points

This study revealed a 13-fold increase of eccDNA in HGSOC compared to normal tissues, with significant enrichment in promoter and coding regions.
eccDNA-derived miRNAs (eccMIRs) were shown to enhance cancer cell proliferation, invasion, and tumor growth through the expression of oncogenic miRNA sequences.
The study highlights the importance of the MMEJ pathway in eccDNA generation and proposes that targeting eccDNA biogenesis in this aggressive malignancy presents a novel therapeutic opportunity.

Abstract Image

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表达miRNA的染色体外环状DNA促进卵巢癌进展。

背景：染色体外环状DNA （eccDNA）已成为肿瘤发生的关键驱动因素，但其在高级别浆液性卵巢癌（HGSOC）中的功能作用仍不清楚。这突出了对HGSOC中eccDNA的丰度、生物成因和功能意义进行全面研究的必要性。方法：为了表征HGSOC中的eccDNA，我们进行了全面的Circle-seq分析，以评估与正常卵巢组织相比，HGSOC组织中eccDNA的丰度和基因组注释。为了验证ecdna生物发生途径的机制，我们进行了依赖于LIG3和POLQ的微同源介导的末端连接（microhomology-mediated end-joining， MMEJ）的靶向敲除实验。HGSOC特异性eccdna前体microRNAs （ecmirs）的功能表征包括体外检测HGSOC细胞和体内肿瘤生长实验。结果：Circle-seq分析显示，与正常卵巢组织相比，HGSOC中eccDNA丰度增加了13倍，其中启动子和编码区显著富集。MMEJ途径被确定为HGSOC中ecdna生物发生的主要途径，并通过连接位点的特征微同源性和LIG3和POLQ敲低实验进行了验证。值得注意的是，hgsoc特异性的eccDNA通常含有功能性的eccMIRs (eccMIR3661、eccMIR618和eccMIR2277)，它们产生致癌的mirna。这些mirna通过下调肿瘤抑制基因和激活关键的致癌途径来促进肿瘤进展。功能实验证实，这些ecmirs显著增强了HGSOC细胞的体外增殖、迁移和侵袭，并促进了体内肿瘤的生长。结论：这些结果强调了eccDNA通过非编码rna介导的调控机制在HGSOC中作为致癌驱动因素，揭示了靶向eccDNA生物发生在这种侵袭性恶性肿瘤中的新的治疗机会。重点：本研究发现，与正常组织相比，HGSOC中的eccDNA增加了13倍，其中启动子区和编码区显著富集。eccdna衍生的miRNAs （ecmirs）通过表达致癌miRNA序列，增强了癌细胞的增殖、侵袭和肿瘤生长。该研究强调了MMEJ通路在eccDNA产生中的重要性，并提出针对这种侵袭性恶性肿瘤的eccDNA生物发生提供了一种新的治疗机会。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Clinical and Translational Medicine Multiple-

CiteScore

15.90

自引率

1.90%

发文量

450

审稿时长

4 weeks

期刊介绍： Clinical and Translational Medicine (CTM) is an international, peer-reviewed, open-access journal dedicated to accelerating the translation of preclinical research into clinical applications and fostering communication between basic and clinical scientists. It highlights the clinical potential and application of various fields including biotechnologies, biomaterials, bioengineering, biomarkers, molecular medicine, omics science, bioinformatics, immunology, molecular imaging, drug discovery, regulation, and health policy. With a focus on the bench-to-bedside approach, CTM prioritizes studies and clinical observations that generate hypotheses relevant to patients and diseases, guiding investigations in cellular and molecular medicine. The journal encourages submissions from clinicians, researchers, policymakers, and industry professionals.