Determination of carcinogenic potential of mineral fibers by 8-hydroxydeoxyguanosine as a marker of oxidative DNA damage in mammalian cells

Our plain-English summary of Determination of carcinogenic potential of mineral fibers by 8-hydroxydeoxyguanosine as a marker of oxidative DNA damage in mammalian cells, by N. Murata-Kamiya, T. Tsutsui, A. Fujino, et al (International Archives of Occupational and Environmental Health, 1997).

The study

• Authors: N. Murata-Kamiya, T. Tsutsui, A. Fujino, H. Kasai, H. Kaji
• Journal: International Archives of Occupational and Environmental Health
• Published: 1997;70(5):321-6
• Cited by: 16 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

8-Hydroxydeoxyguanosine (8-OH-dG) is a typical form of oxidative DNA damage, which causes mutations in vitro and in vivo. To develop a simple method of testing the carcinogenicity of fibrous materials, the formation of 8-OH-dG was determined in the DNA of J774 cells, an established reticulum cell sarcoma line, after treatment with various natural and man-made mineral fibers. The amount of 8-OH-dG was determined using high-pressure liquid chromatography (HPLC) equipped with an electrochemical detector (ECD). We tested three natural mineral fibers (crocidolite, amosite, and chrysotile) and three man-made mineral fibers (ceramic, glass, and potassium octatitanate). Among them, a significant increase in 8-OH-dG formation was observed in the crocidolite- and amosite-treated cells. We also measured the amount of tumor necrosis factor (TNF) produced by J774 cells incubated with the fibrous materials. Cellular TNF production increased after treatment with all the fibers tested, but it was not statistically significant except in the case of chrysotile. Therefore, these results indicate that the mechanism of TNF production is different from that of 8-OH-dG formation, and that the carcinogenicity of various fibrous materials can be better evaluated by measuring the 8-OH-dG level in J774 cellular DNA after treatment with these fibers.

In plain English

This laboratory study in cultured cells aimed to develop a simple test of the cancer-causing potential of fibers. They measured 8-hydroxydeoxyguanosine (8-OH-dG), a form of oxidative DNA damage, in J774 cells, a macrophage-like mouse cell line. Cells were incubated for 18 hours with crocidolite, amosite or chrysotile asbestos, or ceramic, glass or potassium octatitanate man-made fibers. They also measured tumor necrosis factor (TNF), a signalling protein. 8-OH-dG rose with crocidolite dose, peaked at 18 to 20 hours, and returned to control levels by 48 hours. In a first crocidolite experiment, 8-OH-dG and TNF were both significantly higher than in a control where crocidolite was added just before harvesting. In a six-fiber comparison, 8-OH-dG was significantly higher after crocidolite (2 times) and amosite (3 times) than in that type of control. Chrysotile's rise was not significant, and the man-made fibers gave values below that control. TNF rose with all six fibers, significantly only with chrysotile. The authors concluded that fiber carcinogenicity can be better evaluated by measuring 8-OH-dG in these cells. They noted absolute values could not be compared between experiments.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: In vitro cell culture experiment aimed at developing a test method
• Who was studied: J774 cells, a mouse (murine) reticulum cell sarcoma cell line with macrophage-like properties, supplied by the Riken Cell Bank, Tokyo, Japan; no people or animals were studied
• Exposure: UICC reference samples of crocidolite, amosite and chrysotile, and three man-made mineral fibers (ceramic, glass, potassium octatitanate). Each was given at 100 micrograms per ml for 18 hours. Crocidolite was also tested at doses from 0 to 100 micrograms per ml and over different incubation times.
• Main results:
  • In the first experiment (Table 1, six determinations), 8-OH-dG per 10^5 dG was mean 1.41 (SD 0.65) in crocidolite-exposed cells, 0.45 (SD 0.18) in the control with crocidolite, and 0.30 (SD 0.18) in the control without fiber. TNF was 10.19 (SD 3.71) ng/ml in crocidolite-exposed cells versus 5.40 (SD 2.02) in the control with crocidolite. Both increases were statistically significant (P less than 0.05).
  • The control with crocidolite (crocidolite added just before harvesting) was not significantly higher in 8-OH-dG than the control without fiber (P greater than 0.1).
  • In crocidolite-treated cells, 8-OH-dG increased linearly with dose from 0 to 100 micrograms per ml. Cell viability was greater than 90%.
  • With crocidolite, 8-OH-dG peaked between 18 and 20 hours, then decreased gradually and returned to the control level after 48 hours.
  • In the comparison of six fibers (Table 2, three determinations), 8-OH-dG per 10^5 dG was 1.04 (SD 0.05) for crocidolite and 1.89 (SD 0.18) for amosite, versus 0.56 (SD 0.02) for the control with crocidolite; the authors describe these as 2 times and 3 times that control. Both increases were significant (P less than 0.05).
  • For chrysotile, 8-OH-dG was 0.75 (SD 0.16), an apparent increase that was not statistically significant (P greater than 0.1).
  • 8-OH-dG values for the man-made fibers were 0.23 (ceramic), 0.28 (glass) and 0.33 (potassium octatitanate), against a control of 0.56. The natural mineral fibers increased 8-OH-dG more than the man-made fibers.
  • In the six-fiber comparison, TNF increased with all fibers compared with the control with crocidolite (1.15 ng/ml), ranging from 2.13 (amosite) to 3.99 (chrysotile). Only the chrysotile increase was statistically significant (P less than 0.05).
  • In an additional test with magnesium sulfate fibers, the long form induced more TNF than the short form, but neither size increased 8-OH-dG.
• The authors' conclusion: The authors concluded that the TNF and 8-OH-dG responses work by different mechanisms. They concluded that the carcinogenicity of fibrous materials can be better evaluated by measuring 8-OH-dG in J774 cell DNA, and described the procedure as simple and rapid.
• Limitations the authors state:
  • 8-OH-dG and TNF levels differed between experiments run under the same conditions, so absolute values cannot be compared across experiments; the authors used two controls in each experiment.
  • Crocidolite was difficult to remove from the cell preparations, and leftover fiber could raise 8-OH-dG in extracted DNA; the authors added a control with crocidolite to check for this.

Topics

Medical terms in this study, explained in our Lexicon: Carcinogenic, Mineral Fiber, Sarcoma, Crocidolite, Amosite, Chrysotile, Necrosis.

Related studies

• Detection of 8-oxo-2'-deoxyguanosine, a marker of oxidative DNA damage, in culture medium from human mesothelial cells exposed to crocidolite asbestos — Q. Chen, J. Marsh, et al. (1996)
• 8-Hydroxy-2'-deoxyguanosine as a marker of oxidative DNA damage related to occupational and environmental exposures — A. Pilger, H.W. Rüdiger (2006)
• 8-hydroxy-2' -deoxyguanosine (8-OHdG): A critical biomarker of oxidative stress and carcinogenesis — A. Valavanidis, T. Vlachogianni, et al. (2009)
• Patterns of 8-hydroxydeoxyguanosine formation in DNA and indications of oxidative stress in rat and human pleural mesothelial cells after exposure to crocidolite asbestos — H. Fung, Y.W. Kow, et al. (1997)
• Glutathione modulates the formation of 8-hydroxydeoxyguanosine in isolated DNA and mutagenicity in Salmonella typhimurium TA100 induced by mineral fibres — P.J. Howden, S.P. Faux (1996)
• Misreading of DNA templates containing 8-hydroxydeoxyguanosine at the modified base and at adjacent residues — Y. Kuchino, F. Mori, et al. (1987)

Browse more research in International Archives of Occupational and Environmental Health, or return to medical research.