Targeting the NAT1-ENO1-Lactate Axis Destabilizes PD-L1 to Reinvigorate Antitumor Immunity in Colorectal Cancer.

Metabolic dysregulation is a hallmark of tumorigenesis and profoundly impacts immune surveillance; however, the underlying mechanisms and targeted treatments remain limited in colorectal cancer (CRC). Here, we utilize public databases, mouse models, and multi-omics analyses to identify N-acetyltransferase 1 (NAT1) as a critical prognostic-associated gene that emerges as a significant modulator of tumor immunity in CRC. We demonstrate that NAT1 suppresses glycolysis and lactate production, thereby promoting an immune-activated tumor microenvironment (TME). Mechanistically, NAT1 interacts with enolase 1 (ENO1), a key glycolytic enzyme, acetylating it at lysine 343 (K343) and thereby inhibiting its activity. However, loss of NAT1 in tumor cells leads to enhanced ENO1 activation, which in turn drives glycolysis and lactate production. Lactate then binds to TNF receptor-associated factor 6 (TRAF6), promoting its oligomerization and activation, leading to K63-linked ubiquitination of PD-L1, which enhances PD-L1 stability and facilitates immune evasion. Importantly, low NAT1-expressing tumors from CRC patients show increased sensitivity to anti-PD-1 therapy, and NAT1 deficiency significantly improves the efficacy of anti-PD-L1 antibody treatment in preclinical mouse models. Collectively, our findings highlight the critical role of NAT1 in reshaping the TME and suggest that targeting the NAT1-ENO1-lactate axis represents a promising therapeutic strategy to enhance immunotherapy in CRC.