RNA m¹A methyltransferase TRMT61A promotes colorectal tumorigenesis by enhancing ONECUT2 mRNA stability and is a potential therapeutic target

Background: The role of N1-methyladenosine (m¹A) 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 m¹A 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 m¹A-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 m¹A 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 m¹A regulators. Furthermore, we established that TRMT61A promoted CRC tumorigenesis and progression by enhancing the mRNA stability of critical targets in an m¹A-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 m¹A-ONECUT2-SOS1-MAPK/ERK pathway. Targeting TRMT61A showed promise as a therapeutic strategy for treating CRC.