The influence of asbestos dust on the oncogenic transformation of C3H10T 1/2 cells

Our plain-English summary of The influence of asbestos dust on the oncogenic transformation of C3H10T 1/2 cells, by R.C. Brown, A. Poole, G.T. Fleming (Cancer Letters, 1983).

The study

• Authors: R.C. Brown, A. Poole, G.T. Fleming
• Journal: Cancer Letters
• Published: 1983;18(2):221-7
• Cited by: 30 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The cell transforming ability of asbestos dust was investigated using C3H10T 1/2 murine fibroblasts. In a series of experiments both crocidolite and amosite caused no increase in the number of transformed foci over that seen in cultures from untreated cells. The dusts, were, however, capable of augmenting the oncogenic effect of benzo[a]pyrene (BP). This putative synergistic effect was evident when fibres and chemicals were added to cultures as simple mixtures and when BP was adsorbed to the surface of the fibres.

In plain English

This was a laboratory study at the MRC Pneumoconiosis Unit in Penarth, UK. It tested whether asbestos dust could turn mouse embryo cells (the C3H10T1/2 line) into transformed, cancer-like cells. The authors used standard UICC samples of crocidolite and amosite, plus a milled amosite. They tested all three dusts alone. Crocidolite and amosite, but not the milled amosite, were also tested together with benzo[a]pyrene (BP), a cancer-causing chemical, either mixed in or coated onto the fibres. Neither crocidolite nor amosite alone increased the number of transformed cell clusters (foci) above untreated cells. BP alone caused a small increase that was statistically significant only at the highest dose, 2.5 µg/ml. Adding asbestos to low BP doses (0.1 and 0.3 µg/ml) increased foci, differing from controls at the 5% level in all but one case. This held whether BP was mixed in or coated on the fibres. Combined exposure usually killed more cells than either agent alone, an effect the authors called variable. The authors noted that experiments could be compared only qualitatively. They suggested the apparent combined effect may parallel the higher lung tumour rates seen in asbestos workers who smoke.

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 using a cell transformation assay; four experiments
• Who was studied: C3H10T1/2 clone 8 cell line derived from C3H mouse embryo fibroblasts, cells from passage 10 to 13, studied at the MRC Pneumoconiosis Unit, Llandough Hospital, Penarth, UK
• Exposure: UICC standard crocidolite and amosite, and amosite milled for 4 h, each tested alone at 5 or 10 µg/ml. Crocidolite and amosite (not the milled amosite) were also tested with benzo[a]pyrene (0.1 or 0.3 µg/ml), given either as an acetone solution or adsorbed onto the dust. BP alone was tested at 0.1, 0.3 and 2.5 µg/ml.
• Main results:
  • In no experiment did crocidolite or amosite alone increase the number of transformed (type III) foci compared with untreated control cells
  • BP alone caused a small increase in foci that reached statistical significance only at the high dose (2.5 µg/ml) in experiment 4
  • Adding asbestos to low concentrations of BP (0.1 and 0.3 µg/ml) increased the number of foci; in all but one case these groups differed from the control at the 5% level
  • The enhanced transformation with BP plus asbestos was seen both when the agents were added as simple mixtures and when BP was adsorbed onto the dust
  • Simultaneous exposure to dust and BP generally killed more cells than either agent alone, but the authors described this increase in toxicity as variable. In experiment 4, survival with crocidolite plus 0.1 µg/ml BP as a simple mixture was 95%, against 78% with crocidolite alone.
• The authors' conclusion: The authors concluded that asbestos dust alone produced no significant increase in transformed foci. They suggested that the apparent in vitro synergistic effect of BP and asbestos may parallel the enhanced lung tumour production seen in asbestos workers who also smoke cigarettes.
• Limitations the authors state:
  • Each experiment had to be considered separately; the authors said comparison between experiments was difficult on anything other than a qualitative basis
  • In one group in experiment 4 the distribution of foci was so unusual (12 foci on one dish) that confidence limits were not calculated

Topics

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

Medical terms in this study, explained in our Lexicon: Fibroblast, Crocidolite, Amosite, Synergistic Effect.

Related studies

• Asbestos, radiation and oncogenic transformation — T.K. Hei, E.J. Hall, et al. (1984)
• Long-term exposure of mesothelial cells to SV40 and asbestos leads to malignant transformation and chemotherapy resistance — A.L. Cleaver, K. Bhamidipaty, et al. (2014)
• Use of the orthogonal design method to study the synergistic effects of asbestos fibres and 12-O-tetradecanoylphorbol-13-acetate (TPA) in the BALB/3T3 cell transformation system — Y.P. Lu, C. Lasne, et al. (1988)
• Modulating factors in the expression of radiation-induced oncogenic transformation — E.J. Hall, T.K. Hei (1990)
• Study of the cell-transforming ability of amosite and crocidolite asbestos and the ability to induce changes in the metabolism and macromolecular binding of benzo(a)pyrene in C3H10T1/2 cells — A. Poole, R.C. Brown, et al. (1983)
• Asbestos induces mesothelial cell transformation via HMGB1-driven autophagy — J. Xue, S. Patergnani, et al. (2020)

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