Toxicity and carcinogenicity mechanisms of fibrous antigorite

Our plain-English summary of Toxicity and carcinogenicity mechanisms of fibrous antigorite, by V. Cardile, L. Lombardo, E. Belluso, et al (International Journal of Environmental Research and Public Health, 2007).

The study

• Authors: V. Cardile, L. Lombardo, E. Belluso, A. Panico, S. Capella, M. Balazy
• Journal: International Journal of Environmental Research and Public Health
• Published: 2007;4(1):1-9
• Cited by: 21 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

We studied the effects of fibrous antigorite on mesothelial MeT-5A and monocyte-macrophage J774 cell lines to further understand cellular mechanisms induced by asbestos fibers leading to lung damage and cancer. Antigorite is a mineral with asbestiform properties, which tends to associate with chrysotile or tremolite, and frequently occurs as the predominant mineral in the veins of several serpentinite rocks found abundantly in the Western Alps. Particles containing antigorite are more abundant in the breathing air of this region than those typically found in urban ambient air. Exposure of MeT-5A and J774 cells to fibrous antigorite at concentrations of 5-100 microg/ml for 72 hr induced dose-dependent cytotoxicity. Antigorite also stimulated the ROS production, induced the generation of nitrite and PGE2. MeT-5A cells were more sensitive to antigorite than J774 cells. The results of this study revealed that the fibrous antigorite stimulates cyclooxygenase and formation of hydroxyl and nitric oxide radicals. These changes represent early cellular responses to antigorite fibers, which lead to a host of pathological and neoplastic conditions because free radicals and PGE2 play important roles as mediators of tumor pathogenesis. Understanding the mechanisms of the cellular responses to antigorite and other asbestos particles should be helpful in designing rational prevention and treatment approaches.

In plain English

This laboratory study tested fibrous antigorite, a mineral from serpentinite rock in the Western Alps of Italy, on cells grown in culture. It used MeT-5A, a human mesothelial cell line, and J774, a mouse monocyte-macrophage tumour cell line, exposed to 5, 50 or 100 µg/ml of antigorite for 72 hours. Antigorite reduced cell survival in both lines in a dose-dependent way, and the authors wrote that this effect was more evident in J774 cells. At 100 µg/ml, release of LDH, a marker of cell damage, was 2.5 times (MeT-5A) and 3.4 times (J774) that of untreated cells. Reactive oxygen species rose at all doses in MeT-5A cells but only at 100 µg/ml in J774 cells, and nitrite rose in both. At 100 µg/ml, prostaglandin E2 was 28.64 pg/ml in MeT-5A cells and 4.6 pg/ml in J774 cells, compared with 2.4 pg/ml in untreated cells of each line. Antigorite was weaker than crocidolite asbestos on these measures. The authors concluded these changes may be among the biological events behind disease or cancer responses to antigorite.

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; no people or animals were studied
• Who was studied: Two cell lines: MeT-5A, a non-malignant transformed human mesothelial cell line used as a model of normal human mesothelial cells, and J774, a mouse monocyte-macrophage tumour cell line obtained from the American Type Culture Collection
• Exposure: Fibrous antigorite isolated from serpentinite rock collected at Blue Lake near St. Jacques in Aosta, Italy (fibers 14 to 20 µm long and 0.08 to 0.4 µm wide), added to cultures at 5, 50 and 100 µg/ml for 72 hours. Crocidolite fibers were used as a standard reference, and carbonyl iron spheres at 10 µg/ml as a control particle.
• Main results:
  • Antigorite reduced cell viability (MTT test) in a dose-dependent way. The authors wrote that the effect was more evident in J774 than in MeT-5A cells, with 22% and 8% viability at 50 and 100 µg/ml. The sentence does not make clear which cell line these percentages belong to.
  • At 100 µg/ml, LDH leakage (a sign of cell membrane damage) was 2.5 times higher than in untreated MeT-5A cells and 3.4 times higher than in untreated J774 cells
  • Reactive oxygen species (DCFH-DA fluorescence) increased significantly at all three doses in MeT-5A cells. In J774 cells a signal was seen only at 100 µg/ml.
  • Nitrite (a measure of nitric oxide generation) in the culture medium increased in both cell types exposed to antigorite
  • Prostaglandin E2 in untreated MeT-5A and J774 cells was 2.4 ± 0.6 pg/ml and 2.4 ± 0.4 pg/ml. After 72 hours with 100 µg/ml antigorite it was 28.64 ± 1.1 pg/ml in MeT-5A cells and 4.6 ± 1.1 pg/ml in J774 cells. The authors described this as an 11-fold increase in MeT-5A cells and about a 2-fold increase in J774 cells.
  • Compared with crocidolite, antigorite was a less potent inhibitor of cell viability and a weaker stimulus of COX and LDH activity and of reactive oxygen and nitrogen species formation. Carbonyl iron spheres were inactive.
• The authors' conclusion: The authors concluded that fibrous antigorite caused significant biochemical changes in both cell lines, and suggested these changes may directly or indirectly be one of the biological events behind antigorite-related pathological or neoplastic responses

Topics

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

Medical terms in this study, explained in our Lexicon: fibrous antigorite, Macrophage, Antigorite, Asbestiform, Chrysotile, Tremolite, Serpentinite, PGE2.

Related studies

• Fluoro-edenite fibers induce expression of Hsp70 and inflammatory response — V. Cardile, L. Lombardo, et al. (2007)
• In vitro approaches for determining mechanisms of toxicity and carcinogenicity by asbestos in the gastrointestinal and respiratory tracts — B.T. Mossman (1983)
• Antioxidant defense mechanisms and the toxicity of fibrous and nonfibrous particles — K.E. Driscoll, J.M. Carter, et al. (2002)
• Potential toxicity of nonregulated asbestiform minerals: balangeroite from the western Alps. Part 1: Identification and characterization — C. Groppo, M. Tomatis, et al. (2005)
• In vitro toxicity of fibrous glaucophane — A.F. Gualtieri, A. Zoboli, et al. (2021)
• Iron-loaded synthetic chrysotile: a new model solid for studying the role of iron in asbestos toxicity — E. Gazzano, F. Turci, et al. (2007)

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