METTL3, a primary methyltransferase catalyzing RNA N6‐methyladenosine (m6A) modification, has been identified as an oncogene in several cancer types and thus nominated as a potentially effective target for therapeutic inhibition, although current options using this strategy are limited. In this study, we targeted protein‐protein interactions at the METTL3‐METTL14 binding interface to inhibit complex formation and subsequent catalysis of RNA m6A modification. Among candidate peptides, RM3 exhibited the highest anti‐cancer potency, inhibiting METTL3 activity while also facilitating its proteasomal degradation. We then designed a stapled peptide inhibitor (RSM3) with enhanced peptide stability and formation of the α‐helical secondary structure required for METTL3 interaction. Functional and transcriptomic analysis in vivo indicated that RSM3 induced upregulation of programmed cell death‐related genes while inhibiting cancer‐promoting signals. Furthermore, tumor growth was significantly suppressed while apoptosis was enhanced upon RSM3 treatment, accompanied by in‐creased METTL3 degradation, and reduced global RNA methylation levels in two in vivo tumor models. This peptide inhibitor thus exploits a mechanism distinct from other competitive‐binding small molecules to inhibit oncogenic METTL3 activity. Our findings collectively highlight the potential of targeting METTL3 in cancer therapies through peptide‐based inhibition of complex formation and proteolytic degradation.

中文翻译：

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一种针对 N6-腺苷-甲基转移酶亚基 METTL3 和 METTL14 结合界面的钉合肽抑制剂，用于癌症治疗

METTL3 是一种催化 RNA N6-甲基腺苷 (m6A) 修饰的主要甲基转移酶，已被确定为多种癌症类型中的癌基因，因此被提名为治疗抑制的潜在有效靶标，尽管目前使用该策略的选择有限。在这项研究中，我们将 METTL3-METTL14 结合界面上的蛋白质-蛋白质相互作用作为目标，以抑制复合物形成和随后的 RNA m6A 修饰催化。在候选肽中，RM3 表现出最高的抗癌效力，抑制 METTL3 活性，同时促进其蛋白酶体降解。然后，我们设计了一种钉合肽抑制剂 (RSM3)，其具有增强的肽稳定性和 METTL3 相互作用所需的 α ​​螺旋二级结构的形成。体内功能和转录组分析表明，RSM3 诱导程序性细胞死亡相关基因上调，同时抑制促癌信号。此外，在两种体内肿瘤模型中，RSM3 治疗后肿瘤生长被显着抑制，细胞凋亡增强，同时 METTL3 降解增加，整体 RNA 甲基化水平降低。因此，这种肽抑制剂利用了一种不同于其他竞争性结合小分子的机制来抑制致癌 METTL3 活性。我们的研究结果共同强调了通过基于肽的复合物形成和蛋白水解抑制的抑制来靶向 METTL3 在癌症治疗中的潜力。