Department of Radiation Oncology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China.
Department of Radiation Oncology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China.
Clin Transl Med. 2024 Oct;14(10):e70039. doi: 10.1002/ctm2.70039.
Radiotherapy is a primary therapeutic modality for esophageal squamous cell carcinoma (ESCC), but its effectiveness is still restricted due to the resistance of cancer cells to radiation. Long non-coding RNAs (lncRNAs) and N-methyladenosine (m6A) have been shown to play significant roles in tumour radioresistance. However, the precise manifestation and role of m6A-modified lncRNAs in ESCC radioresistance remain unclear.
Bioinformatics analysis was conducted to identify m6A-modified lncRNAs implicated in the radioresistance of ESCC. A series of functional experiments were performed to investigate the function of LNCAROD in ESCC. Methylated RNA immunoprecipitation, chromatin isolation by RNA purification-mass spectrometry, RNA immunoprecipitation, and co-immunoprecipitation experiments were performed to explore the mechanism of m6A-mediated upregulation of LNCAROD expression and the downstream mechanism enhancing the radioresistance of ESCC. The efficacy of LNCAROD in vivo was assessed using murine xenograft models.
Herein, we identified LNCAROD as a novel METTL3-mediated lncRNA that enhanced radioresistance in ESCC cells and was post-transcriptionally stabilised by YTHDC1. Moreover, we confirmed that LNCAROD prevented ubiquitin-proteasome degradation of PARP1 protein by facilitating PARP1-NPM1 interaction, thereby contributing to homologous recombination-mediated DNA double-strand breaks repair and enhancing the radiation resistance of ESCC cells. Silencing LNCAROD in a nude mouse model of ESCC in vivo resulted in slower tumour growth and increased radiosensitivity.
Our findings enhance the understanding of m6A-modified lncRNA-driven machinery in ESCC radioresistance and underscore the significance of LNCAROD in this context, thereby contributing to the development of a potential therapeutic target for ESCC patients.
放射疗法是治疗食管鳞状细胞癌（ESCC）的主要治疗方式，但由于癌细胞对辐射的抵抗，其疗效仍受到限制。长链非编码 RNA（lncRNA）和 N6-甲基腺苷（m6A）已被证明在肿瘤放射抵抗中发挥重要作用。然而，m6A 修饰的 lncRNA 在 ESCC 放射抵抗中的具体表现和作用仍不清楚。
通过生物信息学分析鉴定与 ESCC 放射抵抗相关的 m6A 修饰的 lncRNA。进行了一系列功能实验，以研究 LNCAROD 在 ESCC 中的功能。进行了甲基化 RNA 免疫沉淀、RNA 纯化结合质谱分析、RNA 免疫沉淀和共免疫沉淀实验，以探讨 m6A 介导的 LNCAROD 表达上调的机制及其增强 ESCC 放射抵抗的下游机制。使用小鼠异种移植模型评估 LNCAROD 的体内疗效。
本研究鉴定出 LNCAROD 是一种新型 METTL3 介导的 lncRNA，可增强 ESCC 细胞的放射抵抗，并通过 YTHDC1 进行转录后稳定。此外，我们证实 LNCAROD 通过促进 PARP1-NPM1 相互作用来防止 PARP1 蛋白的泛素-蛋白酶体降解，从而有助于同源重组介导的 DNA 双链断裂修复，并增强 ESCC 细胞的放射抵抗。在 ESCC 的裸鼠模型中体内沉默 LNCAROD 导致肿瘤生长速度减慢和放射敏感性增加。
我们的研究结果增强了对 m6A 修饰的 lncRNA 驱动的 ESCC 放射抵抗机制的理解，并强调了 LNCAROD 在这方面的重要性，从而为 ESCC 患者的治疗提供了潜在的治疗靶点。
