CEBPA-activated METTL1 promotes NSCLC progression and glutamine metabolism by m7G-dependent GOT1 stabilization

Background Methyltransferase-like protein 1 (METTL1) plays a significant role in the progression of non-small cell lung cancer (NSCLC), but its specific regulatory mechanism is not yet fully understood. Methods The levels of METTL1, glutamate oxaloacetate transaminase 1 (GOT1) and CCAAT/enhancer binding protein alpha (CEBPA) were determined by qRT-PCR or western blot. Cell functions were assessed via EdU assay, MTT assay, flow cytometry, transwell assay and sphere formation assay. Glutamine metabolism was evaluated by detecting the levels of relevant indicators. The interaction between METTL1 and GOT1 or CEBPA was analyzed. The role of key molecules in vivo was verified through nude mouse transplanted tumor and tail vein metastasis models. Results METTL1 is significantly upregulated in NSCLC tissues and cells, and silencing of METTL1 can inhibit NSCLC cell proliferation, invasion, stemness and glutamine metabolism. Mechanistically, METTL1 enhanced GOT1 mRNA stability and expression by promoting its N7-methylguanosine (m7G) modification, and overexpression of GOT1 reversed the inhibitory effect of METTL1 knockdown on cell malignant phenotype. Transcription factor CEBPA bound to the METTL1 promoter to activate its transcription. CEBPA knockdown reduced GOT1 expression and inhibited cell progression, while METTL1 overexpression reversed the above effects. In vivo experiments confirmed that silencing METTL1 inhibited tumor growth and lung metastasis, while overexpression of GOT1 attenuated these effects. Conclusion CEBPA transcriptionally activated METTL1 to promote NSCLC cell growth, invasion, stemness and glutamine metabolism by upregulating the m7G modification of GOT1, providing a new potential target for targeted therapy of NSCLC. It should be acknowledged that the identity of the reading protein that recognizes m7G-modified GOT1 mRNA is still undetermined, and this is a limitation of this study that needs to be further revealed in the future.