NAT10 drives chemoresistance in AML through ac4C-dependent stabilization of PLEKHA4

As the only known RNA N4-acetylcytidine (ac4C) acetyltransferase in mammalian cells, NAT10 has been reported to drive tumor progression, yet its role in acute myeloid leukemia (AML) chemoresistance and the underlying mechanisms remain unclear. NAT10 expression was evaluated in AML cells with acquired resistance to cytarabine (Ara-C). Integrated bioinformatic analysis combining a public NAT10-dependent ac4C profiling dataset with AML-related NAT10 knockdown transcriptomic data was conducted to screen out candidate targets. For mechanistic validation, gain- and loss-of-function assays, ac4C dot blot, RNA immunoprecipitation (RIP), ac4C-RIP-qPCR, and mRNA stability analyses were conducted. Functional assays and xenograft models were used to assess chemoresistance. NAT10 was significantly elevated in Ara-C-resistant AML cells and promoted chemoresistance both in vitro and in vivo. Integrated analysis identified PLEKHA4 as a candidate NAT10-dependent ac4C target. Mechanistically, NAT10 directly associated with PLEKHA4 mRNA and increased its ac4C modification, thereby enhancing transcript stability in an enzymatic activity-dependent manner. Catalytic inactivation of NAT10 abolished these effects. Functional rescue experiments further confirmed the role of PLEKHA4 in NAT10-mediated chemoresistance. Moreover, the NAT10-PLEKHA4 axis was associated with increased nuclear β-catenin accumulation, consistent with activation of Wnt/β-catenin signaling. Further, exploratory analyses suggested a potential association between this axis and tunneling nanotube formation with intercellular mitochondrial transfer. Our study identifies a NAT10-driven ac4C-dependent stabilization of PLEKHA4 mRNA as a key mechanism promoting chemoresistance in AML, revealing a previously unrecognized link between RNA acetylation and leukemic adaptation, and suggesting a potential avenue for therapeutic intervention to overcome Ara-C resistance.