title: Chemical induction of interleukin-8, a proinflammatory chemokine, in human epidermal keratinocyte cultures and its relation to cytogenetic toxicity.
abstract: Tumor promoters, proinflammatory cytokines, endotoxins, and protein synthesis inhibitors can modulate cell cycle kinetics of various cell types, stimulate production of reactive oxygen species, and induce keratinocytes to produce interleukin-8 (IL-8), a potent chemotactant for polymorphonuclear neutrophils and T lymphocytes. The aim of this study was to determine whether perturbations of cytogenetic responses correlated with the induction of IL-8 expression. Cultures of primary human keratinocytes were grown in serum-free medium with 5 mumol/L bromodeoxyuridine to label DNA and exposed either to phorbol-13-myristate-12-acetate (PMA) (0.0001-100 ng/ml), cycloheximide (CHX) (0.01-50 micrograms), lipopolysaccharide (0.1-100 micrograms/ml), tumor necrosis factor-alpha (TNF alpha) (3.13-50 ng/ml), or interleukin-1 alpha (IL-1 alpha) (1-182 pg/ml). Metaphase chromosome preparations were stained by a fluorescence-plus-Giemsa technique to differentiate sister chromatids. For IL-8 production, keratinocytes were grown to 70% confluency and then exposed to chemicals for 24 h. Immunoreactive IL-8 was quantitated from the supernatants by ELISA. With the exception of benzo(a)pyrene used as a positive control, none of the agents induced sister chromatid exchanges. However, PMA and TNF alpha induced IL-8 production that coincided with significant cell cycle inhibition. IL-1 alpha had no effect on cytogenetic endpoints, yet stimulated a 6.3-fold increase in IL-8. CHX inhibited cell cycle progression and mitotic activity at concentrations that were 200 times lower than required for IL-8 induction; however, puromycin (0.31-10 micrograms/ml), another protein synthesis inhibitor, did not induce IL-8. At all concentrations tested, TNF alpha reduced the mitotic index by approximately 45%, slowed cell cycle progression by approximately 3.5 h, and induced a flat, albeit large, IL-8 response at concentrations > or = 12.5 ng/ml. These agent-specific response patterns suggest that induction of IL-8 production is not always the inevitable result of cell cycle perturbations or genetic damage.
authors.affiliation: National Institute of Environmental Health Sciences, Environmental Immunology and Neurobiology Section, Research Triangle Park, North Carolina, USA.
authors.forename: J L
authors.initials: JL
authors.lastname: Wilmer
authors.forename: M I
authors.initials: MI
authors.lastname: Luster
mesh_terms: D001973:Bromodeoxyuridine; D002453:Cell Cycle / Q000187:drug effects; D002478:Cells, Cultured; D016895:Culture Media, Serum-Free; D003513:Cycloheximide / Q000494:pharmacology; D004249:DNA Damage / Q000187:drug effects; D004817:Epidermis / Q000378:metabolism; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology*; D016209:Interleukin-8 / Q000096:biosynthesis*; D015603:Keratinocytes / Q000187:drug effects / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008677:Metaphase; D010703:Phorbol Esters / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D016895:Culture Media, Serum-Free; D007375:Interleukin-1; D016209:Interleukin-8; D008070:Lipopolysaccharides; D010703:Phorbol Esters; D014409:Tumor Necrosis Factor-alpha; D003513:Cycloheximide; D001973:Bromodeoxyuridine