ABSTRACT: MAT2A, a key enzyme in the methionine cycle, generates S-adenosylmethionine (SAM), a critical metabolite involved in multiple metabolic pathways and epigenetic regulation. Although MAT2A is frequently overexpressed in tumors, its role in metabolic reprogramming within non-small cell lung cancer (NSCLC) remains poorly understood. Current MAT2A inhibitors, such as AG270, exhibit limited efficacy and are primarily used in MTAP-deleted tumors, highlighting the need to explore additional therapeutic strategies. Here, we employed proteomics and untargeted metabolomics in NSCLC cell lines, complemented by targeted metabolomics, RT-qPCR and ATAC-seq, to systematically characterize MAT2A-rewired metabolic reprogramming and identify potential combination treatment strategies. Totally, MAT2A knockdown or inhibition significantly disrupted fatty acid biosynthesis, cholesterol homeostasis, glycolysis and the transsulfuration pathways. In lipid metabolism, MAT2A inhibition impaired cell proliferation by suppressing fatty acid biosynthesis, and induced cholesterol biosynthesis and efflux impairment. Combining MAT2A inhibitors with the liver X receptor agonist LXR-623, which facilitated cholesterol efflux, effectively depleted intracellular cholesterol and augmented anti-tumor efficacy. In energy metabolism, MAT2A mainly inhibited glycolysis through HIF1A regulation and GLUT1 inhibitor BAY-876 demonstrated a synergetic effect when combined with AG270. In the transsulfuration pathway, MAT2A transcriptionally regulated a key enzyme CBS, and combination treatments using AG270 with either the SLC7A11 inhibitor HG106 or the PHGDH inhibitor NCT-503 exhibited enhanced anti-tumor activity. Overall, our findings identified MAT2A as a critical regulator of metabolic networks in NSCLC and propose several rational combination therapies to enhance MAT2A inhibitor efficacy.
Hu Zhou 
