Morphological transformation of Syrian hamster embryo cells induced by mineral fibres and the alleged enhancement of benzo\[a\]pyrene

Our plain-English summary of Morphological transformation of Syrian hamster embryo cells induced by mineral fibres and the alleged enhancement of benzo[a]pyrene, by S.O. Mikalsen, E. Rivedal, T. Sanner (Carcinogenesis, 1988).

The study

• Authors: S.O. Mikalsen, E. Rivedal, T. Sanner
• Journal: Carcinogenesis
• Published: 1988;9(6):891-9
• Cited by: 19 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The ability of different mineral fibres to induce morphological transformation of Syrian hamster embryo cells has been studied. Increased transformation frequencies were obtained in the presence of chrysotile, crocidolite, amosite, anthophyllite and the glass fibres (GF) 100, while no significant increase in transformation frequency was observed with GF 110 and TiO2. Chrysotile was the most potent of the fibres tested. GF 100 was more potent than crocidolite, amosite and anthophyllite. By comparing transformation frequency and toxicity, it could be concluded that induction of transformation is not caused by unspecific cytotoxic effects. In contrast to some earlier studies, no synergistic effect was observed between benzo[a]pyrene (BaP) and asbestos fibres. Adsorption of BaP to crocidolite fibres had no effect on the transformation frequency. Moreover, crocidolite was not able to promote the transformation of cells pre-exposed to BaP. Electron microscopy studies showed that the fibres were rapidly phagocytosed. Blebs were often formed on the cell surface and were most pronounced after crocidolite exposure. The blebs did not seem to be associated with the areas of physical interaction between the cells and the fibres, but were distributed throughout the cell surface.

In plain English

This laboratory study tested whether mineral fibres cause 'morphological transformation' in cultured Syrian hamster embryo cells. Morphological transformation is a change in how cell colonies look and grow. The authors exposed the cells to UICC reference samples of chrysotile, crocidolite, amosite and anthophyllite asbestos. They also tested glass fibres GF 100 and GF 110 and non-fibrous titanium dioxide. Chrysotile, GF 100, crocidolite, amosite and anthophyllite all significantly increased transformation, while GF 110 and titanium dioxide did not. The highest frequencies came with chrysotile, GF 100 and crocidolite. With a medium change and crocidolite present in both incubation periods, a significant increase was seen at 1.5 micrograms per square centimetre; without a medium change, at 5 micrograms. Combining crocidolite with the chemical benzo[a]pyrene showed no synergistic effect. Crocidolite also did not promote transformation in cells already exposed to benzo[a]pyrene. Electron microscopy showed the cells took up many fibres within 2 to 4 hours. The authors concluded that transformation by these fibres was not due to nonspecific toxicity. They noted that washing did not remove fibres from the dishes, limiting one comparison.

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 transformation experiment, with scanning electron microscopy of fibre-cell interaction
• Who was studied: Primary cultures of Syrian hamster embryo (SHE) cells from embryos at 14 days of gestation; three cell batches (SHE44, SHE48, SHE52); Oslo, Norway laboratory
• Exposure: UICC reference crocidolite, amosite, anthophyllite and chrysotile; glass fibres GF 100 and GF 110 (Johns Manville); titanium dioxide (anatase) as a non-fibrous dust; benzo[a]pyrene alone, combined with crocidolite, or adsorbed onto crocidolite
• Main results:
  • Chrysotile, GF 100, crocidolite, amosite and anthophyllite all induced significant increases in transformation frequency; titanium dioxide and GF 110 did not
  • The highest transformation frequencies were seen with chrysotile, GF 100 and crocidolite
  • With no exchange of medium, a significant increase in transformation was obtained with 5 micrograms crocidolite per square centimetre of the dish
  • With medium change and crocidolite present in both incubation periods, a statistically significant increase in transformation occurred at 1.5 micrograms crocidolite per square centimetre
  • Control transformation frequencies with medium change ranged from 0.00 to 0.62% (mean 0.22%) for cell batch SHE52
  • GF 110 showed a slight increase in transformation that was not statistically significant or dose-dependent
  • Toxicity (on a weight basis) varied by a factor of 100 between chrysotile and GF 110 or titanium dioxide
  • The transforming fibres gave 1% transformation at doses that reduced relative cloning efficiency by 30 to 40%, while GF 110 and titanium dioxide gave no significant transformation at similar toxicity
  • No synergistic effect was observed between benzo[a]pyrene and the asbestos fibres
  • Crocidolite did not promote transformation of cells pre-exposed to benzo[a]pyrene; the authors interpreted the fibres as acting more like an initiator than a promoter
  • In cell batches SHE44 and SHE48, crocidolite added only in the last period increased transformation, unlike in batch SHE52
  • Electron microscopy showed the cells took up (phagocytosed) many fibres within 2 to 4 hours
  • Amosite appeared to cause less bleb formation on the cell surface than crocidolite
• The authors' conclusion: The authors concluded that transformation of SHE cells by chrysotile, amosite, crocidolite, anthophyllite and GF 100 is not caused by unspecific cytotoxic effects of the particles
• Limitations the authors state:
  • Washing and medium change did not remove fibres from the dishes, so the effect of fibres present only in the first incubation period could not be evaluated
  • The reason for different responses between cell batches when crocidolite was added only in the last period is unknown

Topics

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

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

Related studies

• Asbestos and benzo(a)pyrene synergism in the transformation of Syrian hamster embryo cells — J.A. DiPaolo, A.J. DeMarinis, et al. (1983)
• Detection of aneuploidy-inducing carcinogens in the Syrian hamster embryo (SHE) cell transformation assay — D.P. Gibson, M.J. Aardema, et al. (1995)
• Characterization of activated proto-oncogenes in chemically transformed Syrian hamster embryo cells — T.M. Gilmer, L.A. Annab, et al. (1988)
• In vitro transformation of rat pleural mesothelial cells by chrysotile fibres and/or benzo[a]pyrene — M.J. Paterour, J. Bignon, et al. (1985)
• Asbestos and benzo[a]pyrene act synergistically to induce squamous metaplasia and incorporation of [3H]thymidine in hamster tracheal epithelium — B.T. Mossman, A. Eastman, et al. (1984)
• Pulmonary response of hamsters to fibrous glass: chronic effects of repeated intratracheal instillation with or without benzo[a]pyrene — V.J. Feron, P.M. Scherrenberg, et al. (1985)

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