Long-Term Particulate Matter (PM) Exposure Promotes Non-Small-Cell Lung Cancer (NSCLC) Angiogenesis Through Up-Regulation of VEGFA.

BACKGROUND: LUAD, the most common subtype of lung cancer, particularly in non-smokers, is significantly influenced by air pollution from fine particulate matter (PM). One suspected method by which PM contributes to cancer progression is through angiogenesis, which promotes tumor growth and metastasis. This study was conducted to explore the impact of long-term PM exposure on the progression of LUAD, focusing on angiogenesis promotion. METHODS: We conducted an integrative bioinformatics analysis incorporating epidemiological and transcriptomic datasets from public repositories (TCGA and GEO) to evaluate differential VEGFA expression in LUAD tissues and its relationship to regional PM exposure. In vitro and in vivo assays using PM-adapted NSCLC cell lines and murine xenograft models served as secondary confirmatory experiments supporting the computational results. RESULTS: Epidemiological analysis revealed a strong positive correlation between long-term PM exposure and lung adenocarcinoma mortality across U.S. states (r = 0.7638, p < 0.0001), underscoring a population-level impact. Bioinformatics analysis identified a significant upregulation of VEGFA in NSCLC tumors from regions with high PM levels, with VEGFA overexpression also associated with poorer patient survival. Gene ontology and pathway enrichment analyses implicated angiogenesis-related processes. These findings were supported by experimental models, in which long-term PM exposure on human and murine LUAD cell lines (A549, H1299, and LLC) induced VEGFA and p-ERK overexpression. Furthermore, PM-exposed cells enhanced angiogenesis processes, as evidenced by increased endothelial cell tube formation and migration in vitro, and promoted tumor vascularization in a xenograft model. These pro-angiogenesis effects were abrogated following inhibition of the MAPK signaling pathway or blockade of VEGFA. CONCLUSIONS: Our findings reveal a compelling molecular link between PM exposure and NSCLC progression, centered on VEGFA-driven angiogenesis and urging the need to reduce ambient PM exposure to mitigate its oncogenic impact.