Airborne particulate matter upregulates expression of early and late adhesion molecules and their receptors in a lung adenocarcinoma cell line.

Background: Epidemiological evidence associates chronic exposure to particulate matter (PM) with respiratory damage and lung cancer. Inhaled PM may induce systemic effects including inflammation and metastasis. This study evaluated whether PM induces expression of adhesion molecules in lung cancer cells promoting interaction with monocytes.
Methods: The expression of early and late adhesion molecules and their receptors was evaluated in A549 (human lung adenocarcinoma) cells using a wide range of concentrations of PM _2.5 and PM ₁₀ . Then we evaluated cellular adhesion between A549 cells and U937 (human monocytes) cells after PM exposure.
Results: We found higher expression of both early and late adhesion molecules and their ligands in lung adenocarcinoma cells exposed to PM _2.5 and PM ₁₀ particles present in the air pollution at Mexico City from 0.03 μg/cm ² with a statistically significant difference (p ≤ 0.05). PM ₁₀ had stronger effect than PM _2.5 . Both PM also stimulated cellular adhesion between tumor cells and monocytes.
Conclusions: This study reveals a comprehensive expression profile of adhesion molecules and their ligands upregulated by PM _2.5 and PM ₁₀ in A549 cells. Additionally these particles induced cellular adhesion of lung cancer cells to monocytes. This highlights possible implications of PM in two cancer hallmarks i.e. inflammation and metastasis, underlying the high cancer mortality associated with air pollution.
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