Journal Article

Interactions of β-carotene and cigarette smoke in human bronchial epithelial cells

Arti Arora, Celeste A. Willhite and Daniel C. Liebler

in Carcinogenesis

Volume 22, issue 8, pages 1173-1178
Published in print August 2001 | ISSN: 0143-3334
Published online August 2001 | e-ISSN: 1460-2180 | DOI: http://dx.doi.org/10.1093/carcin/22.8.1173
Interactions of β-carotene and cigarette smoke in human bronchial epithelial cells

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Results from recent intervention trials indicated that supplemental β-carotene enhances lung cancer incidence and mortality among smokers. It was hypothesized that β-carotene was exerting its deleterious effects through a prooxidant effect in the smoke-exposed lung. To test this hypothesis we examined the interactions of β-carotene and cigarette smoke in transformed human bronchial epithelial cells. We studied the effects of β-carotene supplementation on rates of gas phase smoke-induced lipid peroxidation, membrane damage and depletion of endogenous antioxidants in BEAS-2B cells. Gas phase cigarette smoke caused cellular β-carotene levels to decrease over time. The oxidation of β-carotene by smoke generated various oxidation products, including 4-nitro-β-carotene, β-apo-carotenals and β-carotene epoxides. Peroxidation of membrane lipids by gas phase smoke progressed at a slower rate than did oxidation of β-carotene and incorporation of β-carotene into the cells did not enhance the overall rate of lipid peroxidation. Additionally, lactate dehydrogenase release during smoke exposure was also unaffected by the presence or absence of β-carotene in cells. β-Carotene incorporation in cells was not found to accelerate the rates of α-tocopherol and glutathione depletion by cigarette smoke. Our results indicate that β-carotene is more sensitive than lipids to cigarette smoke oxidation, but that this preferential oxidation of β-carotene does not lead to a prooxidant effect in human bronchial epithelial cells.

Keywords: AAPH, 2,2′-azo-bis(2-amidinopropane)dihydrochloride; BHT, butylated hydroxytoluene; BSTFA, N,O-bis(trimethylsilyl)trifluoro- acetamide; DPPC, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine; GC/MS, gas chromatographic–mass spectrometric; KGM, keratinocyte growth medium; LDH, lactate dehydrogenase; MeLin, methyl linoleate; PBS, phosphate-buffered saline; THF, tetrahydrofuran.

Journal Article.  4835 words.  Illustrated.

Subjects: Clinical Cytogenetics and Molecular Genetics

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