In vitro activity of silicon carbide whiskers in comparison to other industrial fibers using four cell culture systems

Johnson, Neil; Hoover, Mark D.; Thomassen, David G.; Cheng, Yung Sung; Dalley, Amber M.; Brooks, Antone L.

doi:10.1002/ajim.4700210604

Cited by 23 publications

(15 citation statements)

References 26 publications

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“…However, recent studies have indicated a role for p53 in G2 arrest (20). The markedly reduced ability of JM 100 glass microfiber to induce p53, Cipl, and Gaddl53 proteins is of interest because JM 100 was more toxic to cultured A549 cells than crocidolite on an equal mass/unit area basis (11). The expression of these proteins appears to be independent of cytotoxicity.…”

Section: Resultsmentioning

confidence: 99%

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p53, Cip1, and Gadd153 expression following treatment of A549 cells with natural and man-made vitreous fibers.

Johnson

Jaramillo²

1997

Environ Health Perspect

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DNA damage induced by chemicals and ionizing radiation is associated with the expression of negative regulators of the cell cycle. The arrest of cells in Gl and G2 phases of the cell cycle provides time for DNA repair. Asbestos fibers are carcinogenic when inhaled by both humans and animals; however, the mechanism by which the fibers exert their effect is unknown. This work was undertaken to determine whether the expression of DNA damage-inducible genes differs between crocidolite, a fiber positive for lung tumors, and JM 100 glass microfiber, which is negative for lung tumors when inhaled by rats. Temporal and dose-related expressions of p53, Cipl, and Gadd153 proteins were determined in cultured A549 cells treated with either Union Internationale Contre le Cancer crocidolite or JM 100 for 20 hr and cultured in fresh media. Immunolabeled cells were analyzed by flow cytometry, and the increased number of proteinexpressing cells was determined by subtracting the expression in unexposed cells from exposed cells. Crocidolite induced the expression of all three proteins with a maximum expression after approximately 18 hr in fresh media. At a similar time point, JM 100 did not markedly induce the three proteins. Crocidolite also induced a dose-dependent increase in the number of cells in the G2 phase of the cell cycle. These results show that asbestos behaves like ionizing radiation and genotoxic chemicals by inducing proteins associated with DNA damage and cell-cycle arrest. The clear difference in response between crocidolite and JM 100 may help elucidate the mechanism of action of toxic and nontoxic fibers.

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Section: Resultsmentioning

confidence: 99%

“…This work was conducted to determine whether crocidolite, a known human carcinogen (9), could also induce these DNA damage-inducible genes. A glass microfiber (JM 100), which has been shown to be free of carcinogenic potential in a number of inhalation studies in rats (10) (11).…”

Section: Introductionmentioning

confidence: 99%

p53, Cip1, and Gadd153 expression following treatment of A549 cells with natural and man-made vitreous fibers.

Johnson

Jaramillo²

1997

Environ Health Perspect

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“…Evidence is emerging from both in vitro (21,22) and in vivo (14,23) studies that SiC whiskers can be as toxic as asbestos fibers. In this study we examined a number (20).…”

Section: Discussionmentioning

confidence: 99%

Short-term inhalation and in vitro tests as predictors of fiber pathogenicity.

Cullen

Miller

Davis

et al. 1997

Environ Health Perspect

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A wide range of fiber types was tested in two in vitro assays: toxicity to A549 epithelial cells, as detachment from substrate, and the production of the proinflammatory cytokine tumor necrosis factor (TNF) by rat alveolar macrophages. Three of the fibers were also studied in vivo, using short-term inhalation followed by a) bronchoalveolar lavage to assess the inflammatory response and b) measurement of cell proliferation in terminal bronchioles and alveolar ducts, using incorporation of bromodeoxyuridine (BrdU). The amount of TNF produced by macrophages in vitro depended on the fiber type, with the man-made vitreous fibers, and refractory ceramic fibers being least stimulatory and silicon carbide (SiC) whiskers providing the greatest stimulation. In the epithelial detachment assay there were dose-dependent differences in the toxicity of the various fibers, with long amosite being the most toxic. However, there was no clear relationship to known chronic pathogenicity. Fibers studied by short-term inhalation produced some inflammation, but there was no clear discrimination between the responses to code 100/475 glass fibers and the more pathogenic amosite and SiC. However, measurements of BrdU uptake into lung cells showed that amosite and SiC produced a greater reaction than code 100/475, which itself caused no more proliferation than that seen in untreated lungs. These results mirror the pathogenicity ranking of the fibers in long-term experiments. In conclusion, the only test to show potential as a predictive measure of pathogenicity was that of cell proliferation in lungs after brief inhalation exposure (BrdU assay). We believe that this assay should be validated with a wider range of fibers, doses, and time points. Environ Health Perspect 1 05(Suppl 5):1 235-1 240 (1997)

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“…A single cytotoxicity assay was undertaken using triplicate cultures. The lung epithelial cell (LEC) line (11) was used because the cells are sensitive to the cytotoxic effects of fibers (12). LEC were plated in Ham's F-12 medium supplemented with 10% heat-inactivated newborn calf serum, at a density of 5 x 105 cells per 25-cm diameter culture flask, and cultured as described above.…”

Section: Ancillary Experimentsmentioning

confidence: 99%

Phagosomal pH and Glass Fiber Dissolution in Cultured Nasal Epithelial Cells and Alveolar Macrophages: A Preliminary Study

Johnson¹

1994

Environmental Health Perspectives

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The dissolution rate of glass fibers has been shown to be pH sensitive using in vitro lung fluid simulant models. The current study investigated whether there is a difference in phagosomal pH (ppH) between rat alveolar macrophages (AM) and rat nasal epithelial cells (RNEC) and whether such a difference would influence the dissolution of glass fibers. The ppH was measured in cultured AM and RNEC using flow cytometric, fluorescence-emission rationing techniques with fluorescein-labeled, amorphous silica particles. Glass fiber dissolution was determined in AM and RNEC cultured for 3 weeks with fast dissolving glass fibers (GF-A) or slow dissolving ones (GF-B). The mean diameters of GF-A were 2.7 pm and of GF-B, 2.6 pm, the average length of both fibers was approximately 22 to 25 pm. Dissolution was monitored by measuring the length and diameter of intracellular fibers and estimating the volume, assuming a cylindrical morphology. The ppH of AM was 5.2 to 5.8, and the ppH of RNEC was 7.0 to 7.5. The GF-A dissolved more slowly in RNEC than in AM, and no dissolution was evident in either cell type with GF-B. The volume loss with GF-A after a 3-week culture with AM was 66% compared to 45% for cultured RNEC. These results are different from those obtained using in vitro lung fluidsimulant models where dissolution is faster at higher pH. This difference suggests that dissolution rates of glass fibers in AM should not be applied to the dissolution of fibers in epithelial cells. -Environ Health Prospect 1 02(Suppl 5): 97-102 (1994)

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In vitro activity of silicon carbide whiskers in comparison to other industrial fibers using four cell culture systems

Cited by 23 publications

References 26 publications

p53, Cip1, and Gadd153 expression following treatment of A549 cells with natural and man-made vitreous fibers.

p53, Cip1, and Gadd153 expression following treatment of A549 cells with natural and man-made vitreous fibers.

Short-term inhalation and in vitro tests as predictors of fiber pathogenicity.

Phagosomal pH and Glass Fiber Dissolution in Cultured Nasal Epithelial Cells and Alveolar Macrophages: A Preliminary Study

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