Aggressive and metastatic cancers show enhanced metabolic plasticity¹, but the precise underlying mechanisms of this remain unclear. Here we show how two NOP2/Sun RNA methyltransferase 3 (NSUN3)-dependent RNA modifications—5-methylcytosine (m⁵C) and its derivative 5-formylcytosine (f⁵C) (refs.^2,3,4)—drive the translation of mitochondrial mRNA to power metastasis. Translation of mitochondrially encoded subunits of the oxidative phosphorylation complex depends on the formation of m⁵C at position 34 in mitochondrial tRNA^Met. m⁵C-deficient human oral cancer cells exhibit increased levels of glycolysis and changes in their mitochondrial function that do not affect cell viability or primary tumour growth in vivo; however, metabolic plasticity is severely impaired as mitochondrial m⁵C-deficient tumours do not metastasize efficiently. We discovered that CD36-dependent non-dividing, metastasis-initiating tumour cells require mitochondrial m⁵C to activate invasion and dissemination. Moreover, a mitochondria-driven gene signature in patients with head and neck cancer is predictive for metastasis and disease progression. Finally, we confirm that this metabolic switch that allows the metastasis of tumour cells can be pharmacologically targeted through the inhibition of mitochondrial mRNA translation in vivo. Together, our results reveal that site-specific mitochondrial RNA modifications could be therapeutic targets to combat metastasis.

侵袭性和转移性癌症显示出增强的代谢可塑性¹，但其确切的潜在机制仍不清楚。在这里，我们展示了两种 NOP2/Sun RNA 甲基转移酶 3 (NSUN3) 依赖性 RNA 修饰——5-甲基胞嘧啶 (m ⁵ C) 及其衍生物 5-甲酰基胞嘧啶 (f ⁵ C)（参考文献^2,3,4）如何驱动线粒体 mRNA 的翻译以促进转移。氧化磷酸化复合物的线粒体编码亚基的翻译取决于线粒体 tRNA ^Met中第 34 位m ⁵ C 的形成。米⁵缺乏 C 的人类口腔癌细胞表现出糖酵解水平升高和线粒体功能变化，这些变化不影响细胞活力或体内原发性肿瘤生长；然而，代谢可塑性严重受损，因为线粒体 m ⁵ C 缺陷型肿瘤不能有效转移。我们发现依赖 CD36 的非分裂、转移起始肿瘤细胞需要线粒体 m ⁵C 激活入侵和传播。此外，头颈癌患者中线粒体驱动的基因特征可预测转移和疾病进展。最后，我们证实，这种允许肿瘤细胞转移的代谢开关可以通过抑制体内线粒体 mRNA 翻译来进行药理学靶向。总之，我们的结果表明，位点特异性线粒体 RNA 修饰可能是对抗转移的治疗靶点。