Abstract 1364: Low density lipoprotein cholesterol modulates anti-tumor activity of NK cells within NSCLC tumor microenvironment

Abstract Background: Non-small cell lung cancer (NSCLC) is a leading cause of cancer-related mortality worldwide. While immunotherapy shows promise for improving survival, reliable treatment response biomarkers are still lacking. Despite evidence showing that body mass index (BMI) link to immunotherapy benefits in NSCLC, the underlying mechanism remains unclear. Natural killer (NK) cells are critical for tumor eradication and hold promise in immunotherapy. This prompts the need for better understanding into the biological link between lipid metabolism and NK cells in tumor microenvironment (TME). Therefore, we sought to elucidate how lipids, particularly low-density lipoprotein (LDL) in the NSCLC TME influence NK function. Methods: Primary tumor samples from a cohort of 20 patients with NSCLC were analyzed to assess correlations between tissue-resident NK cells and serum lipid profiles. Public TCGA-LUAD and GEO databases were analyzed to assess the clinical significance of LDL receptor-related gene expression in relation to NK cell infiltration in NSCLC. The effect of LDL/oxidized LDL (oxLDL) on NK cell infiltration was investigated in a 3D tumor model, where A549 lung cancer spheroids were co-cultured with NK cells isolated from healthy donor peripheral blood and analyzed via real-time imaging. NK cell cytotoxicity and phenotype were further assessed using flow cytometry. Results: Analysis of surgically resected NSCLC tumors revealed a positive correlation between increased intra-tumoral NK cell populations and elevated serum levels of total cholesterol, LDL, and apolipoprotein B. In vitro co-culture experiments showed that LDL supplementation significantly enhanced NK cell infiltration into lung cancer spheroids (p<0.001). Notably, infiltrating NK cells exhibited higher levels of lectin-like oxidized LDL (oxLDL) receptor-1 (LOX-1). Analysis of the TCGA-LUAD cohort showed a positive correlation between LOX1 (OLR1) gene expression and NK cell infiltration, which also associated with improved overall survival (HR = 0.734, 95% CI 0.559-0.963, p<0.05). Furthermore, OLR1 expression correlated with enhanced overall survival and progression-free survival in NSCLC patients treated with immune checkpoint inhibitors (ICI). NK cells treated with oxLDL exhibited enhanced killing capacity against A549 cells, potentially driven by an increased presence of LOX1High CD107a+ and Granzyme B+ NK cell populations (p<0.05), along with elevated lipid raft formation (p<0.05) on NK cells following oxLDL exposure. Conclusion: Our findings highlight the interplay between lipid metabolism and NK cell-mediated anti-tumor immunity in NSCLC, suggesting that enhancing LDL/oxLDL uptake by NK cells within the TME could provide a promising therapeutic strategy for advancing NK cell-based immunotherapy in NSCLC. Citation Format: Ying Yang, Kai Wang, Andreas Lundqvist. Low density lipoprotein cholesterol modulates anti-tumor activity of NK cells within NSCLC tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 1364.