DNA Damage and Oxidative Stress of Tobacco Smoke Condensate in Human Bladder Epithelial Cells

Medjda Bellamri, Scott J. Walmsley, Christina V Brown, Kyle Brandt, Dmitri Konorev, Abderrahman Day, Chia Fang Wu, Ming Tsang Wu, Robert J. Turesky

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Smoking is a major risk factor for bladder cancer (BC), with up to 50% of BC cases being attributed to smoking. There are 70 known carcinogens in tobacco smoke; however, the principal chemicals responsible for BC remain uncertain. The aromatic amines 4-aminobiphenyl (4-ABP) and 2-naphthylamine (2-NA) are implicated in BC pathogenesis of smokers on the basis of the elevated BC risk in factory workers exposed to these chemicals. However, 4-ABP and 2-NA only occur at several nanograms per cigarette and may be insufficient to induce BC. In contrast, other genotoxicants, including acrolein, occur at 1000-fold or higher levels in tobacco smoke. There is limited data on the toxicological effects of tobacco smoke in human bladder cells. We have assessed the cytotoxicity, oxidative stress, and DNA damage of tobacco smoke condensate (TSC) in human RT4 bladder cells. TSC was fractionated by liquid-liquid extraction into an acid-neutral fraction (NF), containing polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs, phenols, and aldehydes, and a basic fraction (BF) containing aromatic amines, heterocyclic aromatic amines, and N-nitroso compounds. The TSC and NF induced a time- and concentration-dependent cytotoxicity associated with oxidative stress, lipid peroxide formation, glutathione (GSH) depletion, and apurinic/apyrimidinic (AP) site formation, while the BF showed weak effects. LC/MS-based metabolomic approaches showed that TSC and NF altered GSH biosynthesis pathways and induced more than 40 GSH conjugates. GSH conjugates of several hydroquinones were among the most abundant conjugates. RT4 cell treatment with synthetic hydroquinones and cresol mixtures at levels present in tobacco smoke accounted for most of the TSC-induced cytotoxicity and the AP sites formed. GSH conjugates of acrolein, methyl vinyl ketone, and crotonaldehyde levels also increased owing to TSC-induced oxidative stress. Thus, TSC is a potent toxicant and DNA-damaging agent, inducing deleterious effects in human bladder cells at concentrations of <1% of a cigarette in cell culture media.

Original languageEnglish (US)
Pages (from-to)1863-1880
Number of pages18
JournalChemical research in toxicology
Volume35
Issue number10
DOIs
StatePublished - Oct 17 2022

Bibliographical note

Funding Information:
This research was supported by R01ES030559 (R.J.T.) from the National Institute of Environmental Health Sciences and R01CA220367 and P01 CA160032 (R.J.T.) from the National Cancer Institute, National Institutes of Health. Mass spectrometry was supported by Cancer Center Support Grant CA077598 from the National Cancer Institute.

Publisher Copyright:
© 2022 American Chemical Society. All rights reserved.

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