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

Our plain-English summary of 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, by Y.P. Lu, C. Lasne, R. Lowy, et al (Mutagenesis, 1988).

The study

• Authors: Y.P. Lu, C. Lasne, R. Lowy, I. Chouroulinkov
• Journal: Mutagenesis
• Published: 1988;3(4):355-62
• Cited by: 9 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

An orthogonal design method was used to study the transforming effects of chrysotile and crocidolite asbestos fibres in BALB/3T3 cells. Three experiments, designed by tables L9 (3(4)), L8 (2(7)) and L6 (3(1) x 2(2)) of the orthogonal method respectively, were performed separately. The results indicate exponential reductions in survival of treated cells concomitant with a linear increase in exposure concentrations from 0.1 to 10.0 micrograms/cm2, and that chrysotile was more toxic than crocidolite; the total transformation frequency was significantly increased with both chrysotile and TPA concentrations. There was synergism between chrysotile and TPA in sequential treatment, which suggests that chrysotile is an initiator and has a complete transforming effect at 10.0 micrograms/cm2. Crocidolite only has an initiating-like effect within the dose range of 0.1-10.0 micrograms/cm2, and no synergistic effect when associated with TPA.

In plain English

This was a laboratory study on cells in dishes, not on people or animals. The authors exposed BALB/3T3 cells to UICC chrysotile or UICC crocidolite asbestos fibres, either alone or followed by TPA, which the authors call a promoter. Across three experiments they counted clusters of abnormally changed ("transformed") cells. Chrysotile was more toxic to the cells than crocidolite at all concentrations tested. At the low doses used in the first experiment, chrysotile alone produced no transformed clusters. Chrysotile followed by TPA increased transformation as the dose rose. The authors reported synergism between chrysotile and TPA, meaning the combined effect was greater than the separate effects added together. They found no synergism between crocidolite and TPA. Chrysotile alone produced a complete transforming effect at 10.0 micrograms per square centimetre. The authors concluded that chrysotile acts as an initiator at low concentrations and as a complete carcinogen at 10.0, while crocidolite showed only weak initiating-like activity. They noted that their experiments concentrated only on initiating activity.

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 experiments: three experiments laid out with a statistical approach called orthogonal design
• Who was studied: Cultured BALB/3T3 clone A31-1-1C cells, obtained from IARC, Lyon, and studied in a laboratory in Villejuif, France. Ten thousand cells were seeded per dish, with four or ten dishes per test point.
• Exposure: UICC chrysotile and UICC crocidolite fibres, alone or followed by TPA at 0.25 or 0.5 micrograms per ml. Chrysotile was tested at 0.005 to 10.0 micrograms per square centimetre and crocidolite at 0.1 to 10.0, for 2, 3 or 5 days.
• Main results:
  • Chrysotile was more toxic to the cells than crocidolite at all concentrations tested. Half of the cells survived at approximately 0.40 micrograms per square centimetre for chrysotile and approximately 1.83 for crocidolite. The symbol before these numbers is garbled in the scan.
  • In the first experiment, chrysotile alone (0.005 to 0.5 micrograms per square centimetre) produced no transformed foci. The highest crocidolite concentration (10.0) produced only a low transforming effect.
  • In the first experiment, chrysotile followed by TPA showed a significant dose-response relationship (F = 7.98, P less than 0.05). Crocidolite followed by TPA showed no dose-response relationship (F = 0.55, P greater than 0.05).
  • In the second experiment, there was synergism between chrysotile and TPA (F = 184.8, P less than 0.001). There was no synergism between crocidolite and TPA (F = 5.9, P greater than 0.05).
  • In the second experiment, exposure time (2 or 5 days) did not affect the level of transformation for either fibre.
  • In the third experiment, chrysotile alone showed a complete transforming effect at 10.0 micrograms per square centimetre. Chrysotile alone also showed a dose-response relationship from 0.1 to 10.0 (F = 181.69, P less than 0.01), and synergy with TPA (F = 4.64).
  • In the third experiment, crocidolite showed a dose-response relationship (F = 110.53, P less than 0.01), but much weaker than chrysotile's. It showed no synergy with TPA (F = 1.33, P greater than 0.05).
  • A separate comparison gave a conflicting result for crocidolite. Transformation with crocidolite plus TPA was higher, up to 2-fold, than the sum for crocidolite and TPA tested separately, and most of these differences were significant except at 0.1. The orthogonal-design F-test showed no synergy.
• The authors' conclusion: The authors concluded that chrysotile acts as an initiator at low concentrations and as a complete carcinogen at 10.0 micrograms per square centimetre in this cell system. They concluded that crocidolite shows only weak initiating-like activity at the same dose.
• Limitations the authors state:
  • The experiments concentrated only on the initiating activity of asbestos fibres.

Topics

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

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

Related studies

• Crocidolite induces cell transformation and p53 gene mutation in BALB/c-3T3 cells — F. Lin, Y. Liu, et al. (2000)
• Morphological transformation of Syrian hamster embryo cells induced by mineral fibres and the alleged enhancement of benzo[a]pyrene — S.O. Mikalsen, E. Rivedal, 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)
• Metsovo-tremolite asbestos fibres: in vitro effects on mutation, chromosome aberration, cell transformation and intercellular communication — K. Athanasiou, S.H. Constantopoulos, et al. (1992)
• Asbestos promotes morphological transformation and elevates expression of a gene family invariably induced by tumor promoters in C3H/10T1/2 cells — C.L. Parfett, R. Pilon, et al. (1996)
• The influence of asbestos dust on the oncogenic transformation of C3H10T 1/2 cells — R.C. Brown, A. Poole, et al. (1983)

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