Synthesis of poly(ADP-ribose) in asbestos treated rat pleural mesothelial cells in culture

Our plain-English summary of Synthesis of poly(ADP-ribose) in asbestos treated rat pleural mesothelial cells in culture, by H.Y. Dong, A. Buard, F. Lévy, et al (Mutation Research, 1995).

The study

• Authors: H.Y. Dong, A. Buard, F. Lévy, A. Renier, F. Laval, M.C. Jaurand
• Journal: Mutation Research
• Published: 1995;331(2):197-204
• Cited by: 25 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

To investigate the origin of DNA repair in rat pleural mesothelial cells (RPMC) exposed to asbestos fibers, poly(ADP-ribose) polymerase (PARP) activity was measured in the asbestos-treated cells. As bleomycin has been shown to activate poly(ADP-ribose) synthesis in several cell systems, the response to bleomycin with regard to PARP assay was first investigated. Bleomycin produced a dose-dependent increase of poly(ADP-ribose) synthesis in RPMC. Likewise both chrysotile and crocidolite fibers produced a concentration-dependent PARP activation indicating that the formation of DNA strand breaks is one type of damage produced by asbestos in RPMC. Enhancement of DNA repair, assessed by the measurement of [3H] methylthymidine incorporation in growth arrested cells, was not detectable in the presence of 3-methoxybenzamide (3-MBA), a PARP inhibitor, confirming a relation between PARP activation and DNA repair. The participation of DNA breakage in asbestos toxicity on RPMC was determined by the colorimetric 3-4(5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. There was no relationship between DNA breakage and cytotoxicity since the use of PARP inhibitors did not change cell viability. These results indicate that asbestos produce DNA damage that is repaired in RPMC.

In plain English

This laboratory study used rat pleural mesothelial cells grown in culture, not people. The authors measured PARP enzyme activity, through poly(ADP-ribose) synthesis, as an indirect sign of DNA strand breaks. They first tested the method with bleomycin, a drug that can break DNA strands. It produced a dose-dependent increase in poly(ADP-ribose) synthesis. UICC chrysotile and crocidolite asbestos fibers also produced dose-dependent increases after 24 hours. Compared by fiber weight, the increases were of similar magnitude and levelled off at 20 micrograms per square centimetre; chrysotile has more fibers per unit weight. In growth-arrested cells, a measure of DNA repair rose to 143% of control values with chrysotile and 146% with crocidolite. Adding the PARP inhibitor 3-methoxybenzamide significantly reduced it. Both fibers were toxic to the cells, and PARP inhibitors did not significantly change this toxicity. The authors concluded that asbestos produces DNA damage, including strand breaks, that these cells repair. From the inhibitor results, they suggested that the loss of cell viability was not due to DNA breaks.

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: Laboratory (in vitro) cell culture experiment
• Who was studied: Rat pleural mesothelial cells (RPMC) established in the authors' laboratory in Créteil, France, used between passages 6 and 19. There were no human subjects.
• Exposure: UICC crocidolite and Rhodesian chrysotile A fibers were tested at a range of concentrations, including 10 micrograms per square centimetre in several experiments, mostly for 24 hours. Bleomycin was used as a known DNA-damaging comparison agent.
• Main results:
  • In bleomycin-treated cells, poly(ADP-ribose) synthesis increased in a dose-dependent way. At its plateau, radioactivity was approximately 180% of control values.
  • In cells treated with chrysotile fibers at 10 micrograms per square centimetre, poly(ADP-ribose) synthesis increased in a time-dependent way.
  • After 24 hours with chrysotile or crocidolite, the increase was dose-dependent and, compared by fiber weight, of the same magnitude for both fibers. It reached a plateau at 20 micrograms per square centimetre.
  • In Table 1, mean incorporation (dpm per 2 x 10^5 cells) was 3406 (SD 594) in control cells. It was 7883 (SD 276) with chrysotile and 5565 (SD 46) with crocidolite, each at 10 micrograms per square centimetre.
  • PARP inhibitors strongly inhibited poly(ADP-ribose) synthesis in asbestos-treated cells. For example, the value for crocidolite plus 3-MBA was 196 (SD 15).
  • Both chrysotile and crocidolite were cytotoxic to the cells. Adding PARP inhibitors did not significantly change this cytotoxicity.
  • In growth-arrested cells, thymidine incorporation (a measure of DNA repair) rose to 143% of the control value with chrysotile and 146% with crocidolite. The PARP inhibitor 3-MBA significantly reduced this incorporation.
• The authors' conclusion: The authors concluded that asbestos produces DNA damage that is repaired in rat pleural mesothelial cells, and that DNA strand breaks are one type of damage produced. Because PARP inhibitors did not change cell viability, they suggested that the loss of viability was not due to DNA breaks.
• Limitations the authors state:
  • DNA strand breaks were inferred indirectly from PARP activity. A direct method failed because DNA from asbestos-treated cells interacted with the fibers.
  • Other types of DNA damage besides strand breaks may occur.
  • The two fibers were compared by weight, and chrysotile has more fibers per unit weight than crocidolite.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Chrysotile, Crocidolite.

Medical terms in this study, explained in our Lexicon: Mesothelial Cells, Chrysotile, Crocidolite.

Related studies

• Asbestos exposure affects poly(ADP-ribose) polymerase-1 activity: role in asbestos-induced carcinogenesis — M. Tomasetti, M. Amati, et al. (2011)
• Induction of metaphase and anaphase/telophase abnormalities by asbestos fibers in rat pleural mesothelial cells in vitro — M. Yegles, L. Saint-Etienne, et al. (1993)
• DNA breakage in asbestos-treated normal and transformed (TSV40) rat pleural mesothelial cells — V. Levresse, A. Renier, et al. (2000)
• Role of oxygen derivatives in the cytotoxicity and DNA damage produced by asbestos on rat pleural mesothelial cells in vitro — H. Dong, A. Buard, et al. (1994)
• Modulation of cell and DNA damage by poly(ADP)ribose polymerase in lung cells exposed to H(2)O(2) or asbestos fibres — T. Ollikainen, A. Puhakka, et al. (2000)
• Analysis of cell cycle disruptions in cultures of rat pleural mesothelial cells exposed to asbestos fibers — V. Levresse, A. Renier, et al. (1997)

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