Conditioned medium from asbestos-exposed fibroblasts affects proliferation and invasion of lung cancer cell lines

Our plain-English summary of Conditioned medium from asbestos-exposed fibroblasts affects proliferation and invasion of lung cancer cell lines, by S. Yu, H.H. Choi, I.W. Kim, et al (PloS One, 2019).

The study

• Authors: S. Yu, H.H. Choi, I.W. Kim, T.J. Kim
• Journal: PloS One
• Published: 2019;14(9):e0222160
• Cited by: 5 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

The importance of the role of fibroblasts in cancer microenvironment is well-recognized. However, the relationship between fibroblasts and asbestos-induced lung cancer remains underexplored. To investigate the effect of the asbestos-related microenvironment on lung cancer progression, lung cancer cells (NCI-H358, Calu-3, and A549) were cultured in media derived from IMR-90 lung fibroblasts exposed to 50 mg/L asbestos (chrysotile, amosite, and crocidolite) for 24 h. The kinetics and migration of lung cancer cells in the presence of asbestos-exposed lung fibroblast media were monitored using a real-time cell analysis system. Proliferation and migration of A549 cells increased in the presence of media derived from asbestos-exposed lung fibroblasts than in the presence of media derived from normal lung fibroblasts. We observed no increase in proliferation and migration in lung cancer cells cultured in asbestos-exposed lung cancer cell medium. In contrast, increased proliferation and migration in lung cancer cells exposed to media from asbestos-exposed lung fibroblasts was observed for all types of asbestos. Media derived from lung fibroblasts exposed to other stressors, such as hydrogen peroxide and UV radiation didn't show as similar effect as asbestos exposure. An enzyme-linked immunosorbent assay (ELISA)-based cytokine array identified interleukin (IL)-6 and IL-8, which show pleiotropic regulatory effects on lung cancer cells, to be specifically produced in higher amounts by the three types of asbestos-exposed lung fibroblasts than normal lung fibroblasts. Thus, the present study demonstrated that interaction of lung fibroblasts with asbestos may support the growth and metastasis of lung cancer cells and that chrysotile exposure can lead to lung cancer similar to that caused by amphibole asbestos (amosite and crocidolite).

In plain English

This was a laboratory study using human cell lines grown in culture. No people were studied. The authors exposed IMR-90 human lung fibroblasts (connective-tissue cells) to 50 mg/L of chrysotile, amosite or crocidolite asbestos for 24 hours. They collected the culture liquid and grew three lung cancer cell lines (NCI-H358, Calu-3 and A549) in it, monitoring the cells with a real-time electronic system. After about 30 hours, all three cancer cell lines grew more in liquid from asbestos-exposed fibroblasts than in liquid from unexposed fibroblasts. A549 cells, the only line that could be tested for movement, migrated faster toward the asbestos-exposed fibroblast liquid (P less than 0.05, n = 4). Liquid from asbestos-exposed cancer cells did not boost growth, and asbestos applied directly to cancer cells inhibited their growth. Liquid from fibroblasts stressed by hydrogen peroxide or UV light appeared less potent. Asbestos-exposed fibroblasts released more IL-6 and IL-8, two signaling proteins, at similar levels for all three fiber types. The authors concluded that, in vitro, asbestos-exposed fibroblasts were associated with cancer-cell growth and migration, and that chrysotile might act as much as amphibole asbestos. They noted the exposure was short-term and the model simplified.

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 in which lung cancer cells were grown in culture medium taken from asbestos-exposed lung fibroblasts
• Who was studied: Commercially obtained human cell lines: three lung cancer lines (NCI-H358, bronchioloalveolar carcinoma; Calu-3 and A549, adenocarcinoma) and the IMR-90 human lung fibroblast line, obtained from the American Type Culture Collection. Migration tests used only A549 cells.
• Exposure: UICC standard chrysotile, amosite and crocidolite asbestos at 50 mg/L for 24 hours, applied to fibroblasts or to cancer cells to produce conditioned media. Cancer cells were also exposed to asbestos directly. Comparison stressors were 1 mM hydrogen peroxide for 3 hours and 25 J/m2 UV radiation.
• Main results:
  • NCI-H358, Calu-3 and A549 cancer cells grown in medium from asbestos-exposed fibroblasts (any of the three fiber types) grew more after about 30 hours than cells grown in medium from unexposed fibroblasts
  • Medium from the cancer cells themselves, whether asbestos-exposed or not, did not increase cancer-cell growth compared with plain culture medium (EMEM)
  • Direct exposure of the lung cancer cells to asbestos significantly inhibited their growth (P less than 0.05, n = 4)
  • A549 cells migrated faster toward medium from asbestos-exposed fibroblasts than toward medium from unexposed fibroblasts (P less than 0.05, n = 4). NCI-H358 and Calu-3 cells could not be tested for migration.
  • Medium from A549 cells (asbestos-exposed or not) and asbestos added directly did not enhance A549 migration
  • Cancer cells grown in medium from fibroblasts exposed to hydrogen peroxide or UV light grew similarly to cells in plain medium, or less than cells in medium from unexposed fibroblasts
  • Asbestos-exposed fibroblasts released higher levels of IL-6 and IL-8 than unexposed fibroblasts, with similar levels for all three fiber types (no numerical values given in the text)
• The authors' conclusion: The authors concluded that, in vitro, the progression of asbestos-related lung cancer is substantially associated with asbestos-exposed lung fibroblasts. They also suggested that the interaction of chrysotile with lung fibroblasts might induce lung cancer development as much as amphibole asbestos.
• Limitations the authors state:
  • The media reflected only a relatively short-term (acute) response of fibroblasts to asbestos; long-term exposure was not studied
  • The model is simplified and leaves out the complexity of the real tissue microenvironment

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: Fibroblast, Lung Cancer, Chrysotile, Amosite, Crocidolite, A549 Cells, Asbestos Exposure, Cytokine.

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