Biotoxic effects and gene expression regulation of urban PM in southwestern China.

Atmospheric fine particulate matter (PM) causes severe haze in China and is regarded as a threat to human health. The health effects of PM vary location by location due to the variation in size distribution, chemical composition, and sources. In this study, the cytotoxicity effect, oxidative stress, and gene expression regulation of PM in Chengdu and Chongqing, two typical urban areas in southern China, were evaluated. Urban PM in summer and winter significantly inhibited cell viability and increased reactive oxygen species (ROS) levels in A549 cells. Notably, PM in winter exhibited higher cytotoxicity and ROS level than summer. Moreover, in this study, PM commonly induced cancer-related gene expression such as cell adhesion molecule 1 (PECAM1), interleukin 24 (IL24), and cytochrome P450 (CYP1A1); meanwhile, PM commonly acted on cancer-related biological functions such as cell-substrate junction, cell-cell junction, and focal adhesion. In particular, PM in Chengdu in summer had the highest carcinogenic potential among PM at the two sites in summer and winter. Importantly, cancer-related genes were uniquely targeted by PM, such as epithelial splicing regulatory protein 1 (ESRP1) and membrane-associated ring-CH-type finger 1 (1-Mar) by Chengdu summer PM; collagen type IX alpha 3 chain (COL9A3) by Chengdu winter PM; SH2 domain-containing 1B (SH2D1B) by Chongqing summer PM; and interleukin 1 receptor-like 1 (IL1RL1) and zinc finger protein 42 (ZNF423) by Chongqing winter PM. Meanwhile, important cancer-related biological functions were specially induced by PM, such as cell cycle checkpoint by Chengdu summer PM; macromolecule methylation by Chengdu winter PM; endoplasmic reticulum-Golgi intermediate compartment membrane by Chongqing summer PM; and cellular lipid catabolic process by Chongqing winter PM. Conclusively, in the typical urban areas of southern China, both summer and winter PM illustrated significant gene regulation effects. This study contributes to evaluating the adverse health effects of PM in southern China and providing public health suggestions for policymakers.