In vitro evaluation of genotoxicity and carcinogenicity potential on PM2.5 samples collected from a city in the north of China
Zinan Li1Wenjing Zhang1Guoyan Zhang1,2Peng Zhang1Haiming Jin1Yanmin Nie1Lijuan Qi1Nan Zhang1Hongju Du1Gao Shan1Junyu,Ning1,2Guojun Li1,2
摘要：OBJECTIVE To evaluate the he genotoxicity and carcinogenicity potential of PM2.5 collected in a northern city of China. METHODS PM2.5 samples which were collected from a city in north of China were divided into "Heating supply" group（Nov., 2015 to Feb.,2016） and "Post-heating supply" group（Apr., 2016, to Jul., 2016） according to the heat supply period. Ames test（up to 5 mg/dish） and SOS/umu test（up to 500 μg） were used to evaluate their abilities to induce mutation or DNA damage.The oncogenic potential of the two samples was evaluated by malignant transformation assay（up to21.0 ng/cm~2） based on a human bronchial epithelial cells which is dubbed as BEAS-2 B. RESULTS Ames test and SOS/umu test showed that two groups of samples possess distinguish characteristics in genotoxicity. Samples in "heat supply" period mainly caused DNA damage, but the mutagenic property was weak; "Post-heat supply" samples showed significant mutagenicity, but were less capable of inducing DNA damage. The results of cell malignant transformation test indicates that long-term exposure（6 months） of both groups of samples could induce malignant transformation on BEAS-2 B, which is manifested in increased cell proliferation rate（population doubling time decreased by about one-third）, aberrant growth pattern（anchorage-independent）, resistance to apoptosis-inducing factors, cell epithelialmesenchymal transformation（including morphological change, abnormal expression of E-cadherin and other molecular markers）. In addition, transcriptome studies have shown that epigenetic changes such as DNA methylation are associated with cell malignant transformation induced by PM2.5. CONCLUSION PM2.5 samples from an urban area in north of China have significant genotoxicity, and carcinogenic potential to a certain degree, but the toxicity characteristics of PM2.5 samples between "Heat supply" and "Post-heat supply" period shows great difference.