METTL3: A dual regulator of oral tissue regeneration and malignancy with therapeutic implications for stem cell therapy and chemoresistance.

The RNA N6-methyladenosine (m6A) modification, catalyzed by methyltransferase-like 3 (METTL3), is a key epigenetic regulator of oral health and disease. This narrative review positions METTL3 as a dual-function master switch in oral biology. It promotes stem cell-driven regeneration but also drives disease progression. Physiologically, METTL3 enhances the odontogenic/osteogenic differentiation of dental pulp stem cells (DPSCs). It stabilizes key transcripts (e.g., lncSNHG7, GDF6, STC1) via m6A modification, activating Wnt/β-catenin signaling to foster dentinogenesis and pulp vitality-key goals in regenerative endodontics. Conversely, METTL3 dysregulation promotes oral diseases. It impairs osteogenesis in periodontal stem cells (BMSCs/PDLSCs) via the IGF2BP1/m6A/RUNX2 and PI3K/AKT pathways, worsening bone loss in periodontitis. In oral squamous cell carcinoma (OSCC), METTL3 acts oncogenic. It stabilizes mRNAs like c-Myc, PD-L1, and BMI1 through reader proteins (YTHDF1/IGF2BPs), driving tumor growth, metastasis, and chemoresistance (e.g., to Cisplatin and Anlotinib). Pharmacological inhibition of METTL3 (e.g., with Allocryptopine or Oxymatrine) shows promise by suppressing OSCC progression and rescuing bone formation. We propose METTL3 as a unifying therapeutic target to advance both regenerative dentistry and precision oncology for oral diseases. Targeting METTL3 epitranscriptomics could transform future oral therapies.