Differential inflammatory responses resulted from cellular senescence induced by doxorubicin and antimycin in airway epithelial cells

Abstract

Introduction: Recent theories have implicated a role for senescence in contributing to the worsening of inflammatory responses as implicated in chronic obstructive pulmonary disease (COPD). Nevertheless, in airway epithelial cells, established models are not well-defined. It is also unclear whether the method of senescence induction (ie via DNA damage by doxorubicin, or through eliciting mitochondrial stress by antimycin) affects the inflammatory responses involved. This study aimed at establishing a cellular model of senescence to investigate the inflammatory responses involved. Methods: In order to establish senescence, human bronchial epithelial cells (BEAS-2B) were incubated with doxorubicin (10-50 nM) or antimycin (1-10 μM) for up to 3 days. Growth kinetics was assessed by the MTT assay. Senescence over time was scored using a senescence associated beta-galactosidase (SA-b-GAL) staining kit. Levels of interleukin (IL)–8 in cell supernatant were measured using ELISA. Results: Doxorubicin and antimycin both inhibited cell growth as measured by MTT. In doxorubicin-treated cells, senescence was found as early as 2 days post-exposure; but for antimycin, cells typically established senescence upon 3 days post-exposure. Compared with the untreated control, an increase of IL-8 release was found in doxorubicin treatment, but a suppression of IL-8 release was found in antimycin-treated cells. Conclusion: We conclude that the method of senescence induction can affect the inflammatory response involved.