MYLK-AS1 Enhances Glutamine Metabolism to Promote EGFR Inhibitor Resistance in Non–Small Cell Lung Cancer

Acquired resistance to EGFR tyrosine kinase inhibitors (TKI) limits the efficacy of molecular targeted therapy in non-small cell lung cancer (NSCLC). Metabolic reprogramming is a hallmark of lung cancer that could contribute to TKI resistance. Through systematic screening and verification, we identified a role for the long noncoding RNA MYLK-AS1 supporting acquired TKI resistance in lung cancer. Elevated expression of MYLK-AS1 correlated with TKI resistance in samples from patients with NSCLC and cell lines. c-Myc mediated transcriptional activation of MYLK-AS1, and m6A modification promoted posttranscriptional upregulation. Mechanistically, MYLK-AS1 bound and directly drove phase separation of interleukin enhancer-binding factor 3 (ILF3), thus interacting with the 3' untranslated region of glutamate dehydrogenase 1 (GLUD1) to posttranscriptionally promote its mRNA stability. MYLK-AS1-mediated GLUD1 upregulation accelerated mitochondrial glutamine catabolism, promoting TKI resistance. Inhibition of GLUD1 with the small-molecule inhibitor R162 in TKI-resistant models suppressed cell proliferation in vitro and tumor growth in vivo. Moreover, knockdown of MYLK-AS1 also enhanced drug sensitivity in TKI-resistant patient-derived xenograft models, suggesting its therapeutic potential. Collectively, these findings offer insights into the regulation of TKI resistance from the perspective of phase separation and metabolism and highlight targeting the MYLK-AS1/ILF3/GLUD1 axis as a potential strategy for improving the efficacy of EGFR TKIs in NSCLC. SIGNIFICANCE: MYLK-AS1 promotes resistance to EGFR inhibitors by inducing phase separation of ILF3 to stabilize GLUD1 and stimulate glutamine metabolism, highlighting this axis as a putative therapeutic target for overcoming resistance.