N-acetylcysteine amide, a thiol antioxidant, prevents bleomycin-induced toxicity in human alveolar basal epithelial cells (A549)

Abstract

Bleomycin (BLM), a glycopeptide antibiotic from Streptomyces verticillus, is an effective antineoplastic drug. However, its clinical use is restricted due to the wide range of associated toxicities, especially pulmonary toxicity. Oxidative stress has been implicated as an important factor in the development of BLM-induced pulmonary toxicity. Previous studies have indicated disruption of thiol-redox status in lungs (lung epithelial cells) upon BLM treatment. Therefore, this study focused on (1) investigating the oxidative effects of BLM on lung epithelial cells (A549) and (2) elucidating whether a well-known thiol antioxidant, N-acetylcysteine amide (NACA), provides any protection against BLM-induced toxicity. Oxidative stress parameters, such as glutathione (GSH), malondialdehyde (MDA), and antioxidant enzyme activities were altered upon BLM treatment. Loss of mitochondrial membrane potential (ΔΨm), as assessed by fluorescence microscopy, indicated that cytotoxicity is possibly mediated through mitochondrial dysfunction. Pretreatment with NACA reversed the oxidative effects of BLM. NACA decreased the reactive oxygen species (ROS) and MDA levels and restored the intracellular GSH levels. Our data showed that BLM induced A549 cell death by a mechanism involving oxidative stress and mitochondrial dysfunction. NACA had a protective role against BLM-induced toxicity by inhibiting lipid peroxidation, scavenging ROS, and preserving intracellular GSH and ΔΨm. NACA can potentially be developed into a promising adjunctive therapeutic option for patients undergoing chemotherapy with BLM.

Keywords::

• bleomycin
• N-acetylcysteine amide
• GSH-prodrug
• oxidative stress
• reactive oxygen species

Acknowledgements

The authors appreciate the efforts of Barbara Harris in editing the manuscript.

Declaration of interest

The authors report no declarations of interest. The authors alone are responsible for the content and writing of the paper.

Dr. Ercal is supported by R15DA023409-01A2 from the NIDA, National Institutes of Health.