Integrative whole-exome sequencing and functional validation identify drivers of lung cancer metastasis seeding and colonization in the brain

Lung cancer, the most common primary tumor associated with central nervous system metastasis, develops brain metastases in approximately 30% of advanced-stage patients, yet its molecular mechanisms remain incompletely understood. This study employed whole‑exome sequencing (WES) to systematically investigate the driver genes, molecular characteristics, and potential therapeutic targets of lung cancer brain metastasis. First, monoclonal cells were isolated from the GFP-Luc-LLC (Lewis lung carcinoma) cell line using fluorescence-activated cell sorting (FACS). Subsequently, brain-tropic (Clone 8) and systemically metastatic (Clone 12) clones were identified via intracardiac injection in C57BL/6 mice combined with in vivo imaging (IVIS). After three rounds of in vivo selection, stable brain-parenchyma-colonizing subpopulations (Clone 8_BrM_P3 and GFP_BrM_P3) were obtained. WES revealed that unique mutations in Metap2, Srfbp1, and Cfap65 were identified in the brain-tropic clone, suggesting their potential contribution to brain metastatic predisposition, while mutations in key fructose metabolism genes (Khk, Pfkfb2, and Pfkfb3) were enriched in brain-colonizing subpopulations, suggesting a potential role in tumor cell colonization. In vivo studies demonstrated that dietary fructose significantly promoted brain metastatic growth, while the KHK inhibitor KHK-IN-2 attenuated this effect. This study provides evidence for the involvement of fructose metabolism in lung cancer brain metastasis, identifying potential therapeutic targets for clinical intervention.