Xiaoting Zhang, Na Qin, Fenfen Ji, Hao Su, Haiyun Shang, Hongyan Chen, Hongyan Chen, Dan Huang, Qing Li, Jing Ren, Weixin Liu, Yifei Wang, Wei Kang, Jiabin Wu, Chi‐Chun Wong, Zongwei Cai, Matthew T.V. Chan, William Ka Kei Wu, Jun Yu, Huarong Chen, Huarong Chen
Abstract Background The role of N1‐methyladenosine (m 1 A) in cancer is poorly understood. Here we explored the function of RNA methyltransferase TRNA methyltransferase 61A (TRMT61A) in colorectal cancer (CRC) and its potential as a therapeutic target. Methods RNA m 1 A levels were assessed through liquid chromatography‐mass spectrometry. The expression and clinical significance of TRMT61A were investigated across five human CRC cohorts. The function of TRMT61A was elucidated using CRC cell lines, patient‐derived organoids, xenografts, and transgenic mouse models. Integrated analyses of m 1 A‐sequencing and RNA‐sequencing revealed the underlying mechanisms of TRMT61A. A nanoparticle‐based small interfering RNA (siRNA) delivery system and a specific inhibitor were developed to target TRMT61A. The efficacy and safety of targeting TRMT61A were assessed. Results Our research revealed a consistent increase in TRMT61A expression and total RNA m 1 A levels within primary CRCs. High TRMT61A expression was associated with poor prognosis of CRC patients. Through CRISPR/Cas9 screenings, we identified TRMT61A as the most essential gene among m 1 A regulators. Furthermore, we established that TRMT61A promoted CRC tumorigenesis and progression by enhancing the mRNA stability of critical targets in an m 1 A‐dependent manner. In particular, TRMT61A boosted the mRNA stability of one cut homeobox 2 (ONECUT2), which in turn triggered son of sevenless homolog 1 (SOS1) transcription, leading to the induction of mitogen‐activated protein kinase (MAPK)/extracellular signal‐regulated kinase (ERK) signaling in CRC. Notably, our study underscored the safety and substantial anti‐CRC effects achievable by inhibiting TRMT61A using nanoparticle‐encapsulated siTRMT61A or our newly discovered small molecule compound, pentagalloylglucose. Conclusions Our study unveiled the tumor‐promoting role of TRMT61A in CRC via the m 1 A‐ONECUT2‐SOS1‐MAPK/ERK pathway. Targeting TRMT61A showed promise as a therapeutic strategy for treating CRC.