Reactive oxygen species: their relation to pneumoconiosis and carcinogenesis

Our plain-English summary of Reactive oxygen species: their relation to pneumoconiosis and carcinogenesis, by V. Vallyathan, X. Shi, V. Castranova (Environmental Health Perspectives, 1998).

The study

• Authors: V. Vallyathan, X. Shi, V. Castranova
• Journal: Environmental Health Perspectives
• Published: 1998;106 Suppl 5(Suppl 5):1151-5
• Type of article: Review
• Cited by: 81 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Occupational exposures to mineral particles cause pneumoconiosis and other diseases, including cancer. Recent studies have suggested that reactive oxygen species (ROS) may play a key role in the mechanisms of disease initiation and progression following exposure to these particles. ROS-induced primary stimuli result in the increased secretion of proinflammatory cytokines and other mediators, promoting events that appear to be important in the progression of cell injury and pulmonary disease. We have provided evidence supporting the hypothesis that inhalation of insoluble particles such as asbestos, agricultural dusts, coal, crystalline silica, and inorganic dust can be involved in facilitating multiple pathways for persistent generation of ROS, which may lead to a continuum of inflammation leading to progression of disease. This article briefly summarizes some of the recent findings from our laboratories with emphasis on the molecular events by which ROS are involved in promoting pneumoconiosis and carcinogenesis.

In plain English

This article, by researchers at the National Institute for Occupational Safety and Health in Morgantown, West Virginia, was a review. It summarized recent findings from the authors' own laboratories on reactive oxygen species (ROS), highly reactive forms of oxygen, and their possible role in pneumoconiosis and cancer caused by mineral dusts. The work described was laboratory research on cells, isolated DNA and rats, not studies of workers. In cell tests with dust amounts matched by surface area, asbestos, coal mine dust and silica showed substantial potential to generate ROS. Crocidolite, amosite and chrysotile asbestos all caused breaks in isolated DNA. Chrysotile caused significant breaks, which the authors suggested may reflect its large surface area. Asbestos, coal and silica produced a chemical marker of oxygen-related DNA damage. In unpublished work, crocidolite caused lung immune cells to release an inflammatory signaling protein (TNF-alpha), which the authors linked to metal-driven free radical reactions. The authors concluded that their studies support the hypothesis that ROS are involved in dust-induced pneumoconiosis and cancer. They also noted that the mechanisms remain speculative and that some findings were preliminary.

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: Review summarizing the authors' own laboratory findings (in vitro cell and DNA experiments, plus earlier rat inhalation studies)
• Who was studied: Laboratory systems: human polymorphonuclear leukocytes, alveolar macrophages, isolated DNA, a macrophage cell line (RAW 264.7), mouse epidermal cells, and rats in earlier silica inhalation studies
• Exposure: Mineral dusts: asbestos (amosite, chrysotile, crocidolite), coal mine dust, crystalline silica (freshly fractured and aged), agricultural dusts and other inorganic minerals
• Main results:
  • When dusts were compared at equal surface area, asbestos, coal mine dust and silica showed substantial potential to generate ROS when interacting with phagocytic cells
  • Crocidolite, amosite and chrysotile asbestos all induced DNA strand breaks. Chrysotile caused significant breaks, further enhanced by added iron and hydrogen peroxide, which the authors suggested may be due to its large surface area
  • Asbestos, coal and crystalline silica caused formation of 8-OHdG, a marker of hydroxyl-radical DNA damage, in isolated DNA. The antioxidants catalase and formate inhibited this formation
  • In unpublished data, crocidolite asbestos induced TNF-alpha production from an alveolar macrophage cell line and primary alveolar cells in dose- and time-dependent ways. Blocking NF-kappaB, oxygen radical scavengers and a metal chelator each reduced this effect. The authors concluded that NF-kappaB is involved in asbestos-induced TNF-alpha production through metal-mediated free radical reactions
  • In preliminary studies, ROS generated by crystalline silica and asbestos activated the transcription factor AP-1 in mouse epidermal cells
• The authors' conclusion: The authors concluded that their studies provide evidence supporting the hypothesis that ROS are involved in pneumoconiosis and carcinogenesis induced by mineral particles, and that these processes may be significantly involved in those disease mechanisms
• Limitations the authors state:
  • The authors stated that the mechanisms by which ROS promote pneumoconiosis and carcinogenesis are speculative
  • The authors stated that information is not yet available on the effect of silica particles on p53 activity
  • The authors described the AP-1 activation findings as preliminary

Topics

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

Medical terms in this study, explained in our Lexicon: Reactive Oxygen Species (ROS), Pneumoconiosis, Carcinogenesis, Occupational Exposure, Cytokine, Crystalline, Inflammation.

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