背景：通过调节多种RNA的功能，5-甲基胞嘧啶（m5C）RNA甲基化，特别是由NOP2介导的，参与肿瘤的发生和发展。然而，m5C（尤其是涉及 NOP2）在透明细胞肾细胞癌（ccRCC）中的具体功能和潜在机制仍不清楚。方法：使用蛋白质印迹、实时定量聚合酶链反应（RT-qPCR）和免疫组织化学检测细胞系和患者组织中的NOP2表达。通过一系列体外和体内实验研究了 NOP2 对 ccRCC 细胞的生物学效应。为了探索 NOP2 影响 ccRCC 进展的潜在调控机制，进行了 m5C 亚硫酸氢盐测序、RNA 测序、RNA 免疫沉淀和甲基化 RNA 免疫沉淀 (RIP/MeRIP) RT-qPCR 测定、荧光素酶报告基因测定、RNA 稳定性测定和生物信息学分析。结果：NOP2 表达在 ccRCC 组织中显着上调，并且与不良预后相关。此外，功能丧失和功能获得检测表明，NOP2 改变了 ccRCC 细胞的增殖、迁移和侵袭。从机制上讲，NOP2 刺激载脂蛋白 L1 (APOL1) mRNA 的 m5C 修饰，m5C 阅读器 YBX1 通过识别并结合 3'-非翻译区的 m5C 位点稳定 APOL1 mRNA。沉默 APOL1 表达可抑制体外 ccRCC 细胞增殖和体内肿瘤形成。此外，NOP2/APOL1 通过 PI3K-Akt 信号通路影响 ccRCC 进展。结论：NOP2 作为 ccRCC 的癌基因，通过 m5C 依赖性的 APOL1 稳定作用促进肿瘤进展，进而调节 PI3K-Akt 信号通路，这表明它是 ccRCC 的潜在治疗靶点。© 作者。

Background: By regulating the functions of multiple RNAs, 5-methylcytosine (m5C) RNA methylation, particularly mediated by NOP2, is involved in tumorigenesis and developments. However, the specific functions and potential mechanisms of m5C, especially involving NOP2, in clear-cell renal cell carcinoma (ccRCC), remain unclear. Methods: NOP2 expression in cell lines and patient tissues was detected using western blotting, quantitative real-time polymerase chain reaction (RT-qPCR), and immunohistochemistry. The biological effects of NOP2 on ccRCC cells were investigated through a series of in vitro and in vivo experiments. To explore the potential regulatory mechanisms by which NOP2 affects ccRCC progression, m5C bisulfite sequencing, RNA-sequencing, RNA immunoprecipitation and methylated RNA immunoprecipitation (RIP/MeRIP) RT-qPCR assay, luciferase reporter assay, RNA stability assay, and bioinformatic analysis were performed. Results: NOP2 expression was significantly upregulated in ccRCC tissues and was associated with poor prognosis. Moreover, loss-of-function and gain-of-function assays demonstrated that NOP2 altered ccRCC cell proliferation, migration, and invasion. Mechanistically, NOP2 stimulated m5C modification of apolipoprotein L1 (APOL1) mRNA, and m5C reader YBX1 stabilized APOL1 mRNA through recognizing and binding to m5C site in the 3'-untranslated regions. Silencing APOL1 expression inhibited ccRCC cell proliferation in vitro and tumor formation in vivo. Furthermore, NOP2/APOL1 affected ccRCC progression via the PI3K-Akt signaling pathway. Conclusion: NOP2 functions as an oncogene in ccRCC by promoting tumor progression through the m5C-dependent stabilization of APOL1, which in turn regulates the PI3K-Akt signaling pathway, suggesting a potential therapeutic target for ccRCC.© The author(s).