NAT10-mediated ac4C acetylation of PPFIA4 mRNA drives papillary thyroid carcinoma progression and lymph node metastasis by rewiring focal adhesion signaling

Thyroid cancer, predominantly papillary thyroid carcinoma (PTC), has become the fastest-growing malignancy in terms of incidence rate. RNA epitranscriptomic modifications such as N 4 -acetylcytidine (ac 4 C) play crucial roles in cancer progression, yet their function in PTC remains unclear. This study demonstrates that NAT10 and ac 4 C levels are upregulated in PTC and correlate with lymph node metastasis. The transcription factor ATF2, highly expressed in PTC, drives NAT10 upregulation. Combined acRIP-seq and RNA-seq analyses identified PPFIA4 as a key downstream target of NAT10. Mechanistically, NAT10 catalyzes ac 4 C modification on PPFIA4 mRNA, enhancing its stability. We further mapped the specific ac 4 C site on PPFIA4 mRNA and demonstrated its functional necessity for oncogenicity. PPFIA4 acted as a scaffold protein that promoted the aggregation of leukocyte common antigen‑related (LAR) phosphatase while inhibiting its enzymatic activity. This inhibition of LAR activated the FAK/Src/paxillin signaling axis, leading to increased focal adhesion formation and ultimately promoting tumor cell migration and invasion. Critically, in vivo studies confirmed that combined treatment with the selective NAT10 inhibitor Remodelin and Src family kinase inhibitor dasatinib effectively suppressed malignant progression and metastasis in PTC models. Collectively, this study identified the NAT10/ac 4 C-mediated epitranscriptional pathway as a driver of PTC progression and a promising therapeutic target.