CRISPR/Cas9 library screening uncovered CCT2 as a critical driver of acquired resistance to EGFR-targeted therapy by stabilizing TMX1 in non-small cell lung cancer.

In the treatment of non-small cell lung cancer (NSCLC) with epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), the emergence of acquired resistance remains a significant challenge. Elucidating the underlying mechanisms of resistance is crucial for developing novel strategies to overcome or delay therapeutic escape. To this end, this study aimed to identify key drivers of EGFR-TKIs resistance and explore actionable targets for intervention. We investigated resistance mechanisms by integrating CRISPR/Cas9-based genome-wide screening with tandem mass tag (TMT) proteomic analysis, and virtually screened bioactive small molecule libraries to identify compounds capable of restoring EGFR-TKIs sensitivity. The multi-omics approach revealed that CCT2 is a critical mediator of resistance to third-generation EGFR-TKIs in lung cancer, with higher expression of CCT2 observed in resistant cells compared to sensitive cells. Mechanistically, CCT2 recruits tripartite motif-containing protein 28 (TRIM28) to catalyze SUMO2 modification of thioredoxin-related transmembrane protein 1 (TMX1), inhibiting its ubiquitination and enhancing protein stability. This post-translational modification (PTM) promotes TMX1-dependent reactive oxygen species (ROS) clearance, thereby conferring resistance. Importantly, pharmacological inhibition with the compound HY-10127, identified through virtual screening, effectively restored EGFR-TKIs sensitivity in resistant cell lines and delayed the development of resistance in xenograft models. The findings establish the CCT2/TRIM28/TMX1/ROS axis as a novel resistance mechanism in EGFR-mutated lung cancer, and targeting this pathway with HY-10127 represents a promising strategy to overcome resistance to third-generation EGFR-TKIs, providing preclinical rationale for clinical translation. These discoveries advance our understanding of molecular resistance mechanisms and offer potential therapeutic targets for improving lung cancer prognosis.