Fine particulate matter (PM2.5) promotes chemoresistance and aggressive phenotype of A549 lung cancer cells

Lung cancer is one of the most aggressive malignancies with a high mortality rate. In large cities, particulate matter (PM) is a common air pollutant. High PM levels with aerodynamic size ≤2.5 μm (PM_2.5) associates with lung cancer incidence and mortality. In this work, we explored PM_2.5 effects on the behavior of lung cancer cells. To this, we chronically exposed A549 cells to increasing PM_2.5 concentrations collected in México City, then evaluating cell proliferation, chemoresponse, migration, invasion, spheroid formation, and P-glycoprotein and N-cadherin expression. Chronic PM_2.5 exposure from 1 μg/cm² stimulated A549 cell proliferation, migration, and chemoresistance and upregulated P-glycoprotein and N-cadherin expression. PM_2.5 also induced larger multicellular tumor spheroids (MCTS) and less disintegration compared with control cells. Therefore, these results indicate lung cancer patients exposed to airborne PM_2.5 as urban pollutant could develop more aggressive tumor phenotypes, with increased cell proliferation, migration, and chemoresistance.