Effect of ac4C acetyltransferase NAT10 on tumor progression via ATF4/ASNS mediated asparagine biosynthesis in osteosarcoma.

234 Background: Osteosarcoma is the most common primary malignant bone tumor in children and adolescents, characterized by high malignancy, high mortality, and high disability rates. Investigating the mechanism of osteosarcoma progression, identifying new targets, and developing effective therapy are of great significance for improving patient clinical outcomes. NAT10-mediated ac4C modification is widely present in mRNA and plays important roles in multiple biological processes of mRNA. NAT10 and ac4C modification also play a crucial role in the occurrence and development of malignant tumors such as bladder cancer, esophageal cancer, and breast cancer. Methods: Through RNA-seq and functional screening, NAT10 was identified as the potential therapeutic target. The biological functions of NAT10 and ac4C modification in osteosarcoma were explored in vivo and in vitro. Downstream target of NAT10 was identified through acRIP-seq combined with RNA-seq. The ac4C modification of downstream target gene were detected using RIP-qPCR and its regulatory effect on mRNA stability was explored using RNA half-life analysis. Drug screening was performed using FDA-approved drugs and a small molecule compound library to identify NAT10 inhibitors. The efficacy of inhibitors in osteosarcoma treatment is validated through in vivo, in vitro experiments and patient-derived tumor xenograft (PDX) models. Results: Functional screening targeting RNA modification regulatory factors demonstrated that inhibiting NAT10 significantly reduced the proliferation, migration and invasion of osteosarcoma cells. NAT10 knockout significantly inhibited the proliferation and metastasis of osteosarcoma cells, as well as the malignant progression in vivo. The acRIP-seq and RNA-seq revealed that ATF4 is a downstream target gene regulated by NAT10 in osteosarcoma. NAT10 promoted ac4C modification of ATF4 mRNA, enhanced the stability of ATF4 mRNA, and ATF4 promoted the transcription and expression of ASNS. ASNS catalyzes the synthesis of asparagine (Asn), thereby promoting the malignant progression of osteosarcoma. Drug screening identified Paliperidone and AG-401 as potential inhibitors of NAT10. Through cell functional experiments, orthotopic osteosarcoma models, organoids model, and PDX models, it was demonstrated that Paliperidone and AG-401 can inhibit the malignant progression of osteosarcoma. Conclusions: NAT10 was highly expressed in osteosarcoma and associated with patient prognosis. Through ac4C modification, NAT10 regulated the synthesis of asparagine mediated by ATF4/ASNS, providing materials for protein and nucleotide synthesis in tumor cells, thus promoting the malignant progression of osteosarcoma. Paliperidone and AG-401 were identified as potential NAT10 inhibitors and targeting NAT10 could be a promosing strategy in osteosarcoma treatment.