Immunology and Reproduction Biology Laboratory & State Key Laboratory of Analytical Chemistry for Life Science, Medical School, Nanjing University, Nanjing, Jiangsu, 210093, China.
Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, Jiangsu, 210093, China.
J Exp Clin Cancer Res. 2023 Sep 28;42(1):252. doi: 10.1186/s13046-023-02837-4.
NONO-TFE3 rearranged renal cell carcinoma (NONO-TFE3 rRCC) is one of a subtype of TFE3 rRCCs with high malignancy and poor prognosis. Compared with clear cell RCC, NONO-TFE3 rRCC shows a preference for mitochondrial respiration. We recently identified that the upregulation of nicotinamide ribokinase 2 (NMRK2) was associated with enhanced mitochondrial respiration and tumor progression in TFE3 rRCC.
A tumor-bearing mouse model was established to verify the pro-oncogenic effect of NMRK2 on NONO-TFE3 rRCC. Then the expression of NMRK2 RNA and protein was detected in cell lines and patient specimens. The NMRK2 transcripts were Sanger-sequenced and blasted at NCBI website. We constructed dCas13b-HA system to investigate the factors binding with NMRK2 RNA. We also used molecular experiments like RIP-seq, IP-MS, FISH and fluorescence techniques to explore the mechanisms that long non-coding RNA (lncRNA) like NMRK2 mRNA promoted the mitochondrial respiration of NONO-TFE3 rRCC. The efficacy of the combination of shRNA (NMRK2)-lentivirus and metformin on NONO-TFE3 rRCC was assessed by CCK-8 assay.
In this study, we confirmed that NMRK2 showed transcriptional-translational conflict and functioned as lncRNA like mRNA in the NONO-TFE3 rRCC. Furthermore, we revealed the molecular mechanism that NONO-TFE3 fusion suppressed the translation of NMRK2 mRNA. Most importantly, three major pathways were shown to explain the facilitation effects of lncRNA like NMRK2 mRNA on the mitochondrial respiration of NONO-TFE3 rRCC in an NAD kinase-independent manner. Finally, the efficacy of combination of shRNA (NMRK2)-lentivirus and metformin on NONO-TFE3 rRCC was demonstrated to be superior than either agent alone.
Overall, our data comprehensively demonstrated the mechanisms for the enhanced mitochondrial respiration in NONO-TFE3 rRCC and proposed lncRNA like NMRK2 mRNA as a therapy target for NONO-TFE3 rRCC.
NONO-TFE3 融合相关性肾细胞癌（NONO-TFE3 rRCC）是 TFE3 rRCC 的一种亚型，具有高度恶性和不良预后。与透明细胞 RCC 相比，NONO-TFE3 rRCC 更倾向于线粒体呼吸。我们最近发现，烟酰胺核糖激酶 2（NMRK2）的上调与 TFE3 rRCC 中的线粒体呼吸增强和肿瘤进展有关。
建立荷瘤小鼠模型，验证 NMRK2 对 NONO-TFE3 rRCC 的致癌作用。然后在细胞系和患者标本中检测 NMRK2 RNA 和蛋白质的表达。使用 Sanger 测序对 NMRK2 转录本进行测序，并在 NCBI 网站上进行 Blast 分析。我们构建了 dCas13b-HA 系统来研究与 NMRK2 RNA 结合的因素。我们还使用 RIP-seq、IP-MS、FISH 和荧光技术等分子实验来探讨长非编码 RNA（lncRNA）样 NMRK2 mRNA 促进 NONO-TFE3 rRCC 线粒体呼吸的机制。通过 CCK-8 测定评估 shRNA（NMRK2）-慢病毒和二甲双胍对 NONO-TFE3 rRCC 的联合治疗效果。
在这项研究中，我们证实 NMRK2 表现出转录-翻译冲突，并在 NONO-TFE3 rRCC 中作为 lncRNA 样 mRNA 发挥作用。此外，我们揭示了 NONO-TFE3 融合抑制 NMRK2 mRNA 翻译的分子机制。最重要的是，有三大途径表明，lncRNA 样 NMRK2 mRNA 以 NAD 激酶非依赖的方式促进 NONO-TFE3 rRCC 的线粒体呼吸。最后，证明 shRNA（NMRK2）-慢病毒和二甲双胍联合应用对 NONO-TFE3 rRCC 的疗效优于单独应用任何一种药物。
总的来说，我们的数据全面阐明了 NONO-TFE3 rRCC 中线粒体呼吸增强的机制，并提出 lncRNA 样 NMRK2 mRNA 作为 NONO-TFE3 rRCC 的治疗靶点。
