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Chrysotile Causes Human Bronchial Epithelial Cell Apoptosis in Response to the Fas-Mediated Apoptosis Pathway

Aims: Asbestos is harmful to human health. However, the pathogenicity of chrysotile is a controversial matter. This study aimed to investigate the apoptosis of a human bronchial epithelial cell line (BEAS-2B) exposed to chrysotile that may function in part through the Fas death receptor pathway. Methods: Cultured human BEAS-2B cells were treated with chrysotile and cell viability was evaluated by CCK-8 assay. The induction of cell apoptosis was evaluated by FACS analysis. mRNA expression levels of Fas, caspase-3, and caspase-8 were evaluated quantitatively by real-time PCR. The expression of Fas, caspase-3, and caspase-8 proteins were evaluated by Western blot. Meanwhile, cells were preincubated with various concentrations of anti-Fas antibody (CH11) and antagonistic anti-Fas antibody (ZB4). Results: Chrysotile inhibits proliferation, induces apoptosis, and upregulates the expression of Fas, caspase-3, and caspase-8. The role of Fas as a regulator of chrysotile-induced apoptosis in BEAS-2B cells was tested by the prominent increase in and partial blockade of the apoptotic rate with CH11 and ZB4. When CH11 was pretreated, a synergistic effect was apparent on chrysotile-induced apoptosis and the mRNA and protein expression levels of Fas and cleaved caspase-3. Conclusion: Chrysotile causes the apoptosis of BEAS-2B cells via the Fas death receptor pathway. The Fas-mediated apoptosis pathway plays an important role in chrysotile-induced apoptosis of BEAS-2B cells in vitro.