Department of Gynecologic Oncology, Fudan University Shanghai Cancer Center, Shanghai, 200032, China.
Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, China.
Mol Cancer. 2024 Jul 5;23(1):139. doi: 10.1186/s12943-024-02055-2.
Radioresistance is the leading cause of death in advanced cervical cancer (CC). Dysregulation of RNA modification has recently emerged as a regulatory mechanism in radiation and drug resistance. We aimed to explore the biological function and clinical significance of 5-methylcytosine (mC) in cervical cancer radiosensitivity.
The abundance of RNA modification in radiotherapy-resistant and sensitive CC specimens was quantified by liquid chromatography-tandem mass spectrometry. The essential RNA modification-related genes involved in CC radiosensitivity were screened via RNA sequencing. The effect of NSUN6 on radiosensitivity was verified in CC cell lines, cell-derived xenograft (CDX), and 3D bioprinted patient-derived organoid (PDO). The mechanisms of NSUN6 in regulating CC radiosensitivity were investigated by integrative mC sequencing, mRNA sequencing, and RNA immunoprecipitation.
We found a higher abundance of mC modification in resistant CC samples, and NSUN6 was the essential mC-regulating gene concerning radiosensitivity. NSUN6 overexpression was clinically correlated with radioresistance and poor prognosis in cervical cancer. Functionally, higher NSUN6 expression was associated with radioresistance in the 3D PDO model of cervical cancer. Moreover, silencing NSUN6 increased CC radiosensitivity in vivo and in vitro. Mechanistically, NDRG1 was one of the downstream target genes of NSUN6 identified by integrated mC-seq, mRNA-seq, and functional validation. NSUN6 promoted the mC modification of NDRG1 mRNA, and the mC reader ALYREF bound explicitly to the mC-labeled NDRG1 mRNA and enhanced NDRG1 mRNA stability. NDRG1 overexpression promoted homologous recombination-mediated DNA repair, which in turn led to radioresistance in cervical cancer.
Aberrant mC hypermethylation and NSUN6 overexpression drive resistance to radiotherapy in cervical cancer. Elevated NSUN6 expression promotes radioresistance in cervical cancer by activating the NSUN6/ALYREF-mC-NDRG1 pathway. The low expression of NSUN6 in cervical cancer indicates sensitivity to radiotherapy and a better prognosis.
放射抵抗是晚期宫颈癌（CC）死亡的主要原因。RNA 修饰的失调最近成为放射和耐药性的调节机制。我们旨在探索 5-甲基胞嘧啶（mC）在宫颈癌放射敏感性中的生物学功能和临床意义。
通过液相色谱-串联质谱法定量测定放射抵抗和敏感 CC 标本中 RNA 修饰的丰度。通过 RNA 测序筛选涉及 CC 放射敏感性的关键 RNA 修饰相关基因。在 CC 细胞系、细胞衍生异种移植（CDX）和 3D 生物打印患者来源的类器官（PDO）中验证 NSUN6 对放射敏感性的影响。通过整合 mC 测序、mRNA 测序和 RNA 免疫沉淀研究 NSUN6 调节 CC 放射敏感性的机制。
我们发现抗性 CC 样本中 mC 修饰的丰度更高，而 NSUN6 是涉及放射敏感性的关键 mC 调节基因。NSUN6 过表达与宫颈癌的放射抵抗和不良预后相关。功能上，更高的 NSUN6 表达与宫颈癌 3D PDO 模型中的放射抵抗有关。此外，沉默 NSUN6 可增加体内和体外 CC 的放射敏感性。从机制上讲，NDRG1 是通过整合 mC-seq、mRNA-seq 和功能验证鉴定的 NSUN6 的下游靶基因之一。NSUN6 促进 NDRG1 mRNA 的 mC 修饰，mC 阅读器 ALYREF 特异性结合 mC 标记的 NDRG1 mRNA 并增强 NDRG1 mRNA 的稳定性。NDRG1 过表达促进同源重组介导的 DNA 修复，从而导致宫颈癌的放射抵抗。
异常的 mC 高甲基化和 NSUN6 过表达驱动宫颈癌对放疗的抵抗。升高的 NSUN6 表达通过激活 NSUN6/ALYREF-mC-NDRG1 通路促进宫颈癌的放射抵抗。宫颈癌中 NSUN6 的低表达表明对放疗敏感且预后更好。
