In vitro transformation of rat pleural mesothelial cells by chrysotile fibres and/or benzo\[a\]pyrene

Our plain-English summary of In vitro transformation of rat pleural mesothelial cells by chrysotile fibres and/or benzo[a]pyrene, by M.J. Paterour, J. Bignon, M.C. Jaurand (Carcinogenesis, 1985).

The study

• Authors: M.J. Paterour, J. Bignon, M.C. Jaurand
• Journal: Carcinogenesis
• Published: 1985;6(4):523-9
• Cited by: 33 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Rat pleural mesothelial cells (RPMC) were treated, in vitro, in a two-stage model of carcinogenesis. RPMC obtained from passage 12th were treated once with 1 microgram/ml of benzo-[a]pyrene (BP) and from passage 13th to 40th with 0.4 microgram/cm2 of chrysotile fibres (Chr). Transformation was determined by the observation of the colonies formed when the cells were plated at low density. Colonies were classified into four classes according to the level of lack in contact inhibition between cells (0 to III). BP as well as chrysotile fibres were potent in inducing a high proportion of type III colonies which were not observed in control series. In addition, there was no synergistic effect between BP and Chr. These results would indicate that chrysotile fibres do not act as a promoter on rat pleural mesothelial cells in culture, but induce morphologically transformed colonies.

In plain English

This was a laboratory study of cells taken from the chest lining (parietal pleura) of a Sprague-Dawley rat and grown in culture. The authors tested a two-stage model of cancer development, using the chemical benzo[a]pyrene (BP) as a possible starter and Rhodesian chrysotile fibres as a possible promoter. Cultures received BP once, chrysotile weekly over many passages, BP followed by chrysotile, or no treatment. Changes were judged by how cells grew in colonies, graded from type 0 (normal) to type III (cells piled up throughout the colony). In the BP series and the chrysotile-only series, type III colonies appeared from passage 22. After passage 29 they rose to 55% with BP and roughly 35% in both chrysotile-treated series. Untreated cultures showed type III colonies only briefly, at about 5%. Combining BP and chrysotile gave no additive or multiplicative effect. The authors concluded that chrysotile did not seem to act as a promoter of BP in these cells, but induced morphologically transformed colonies. They noted that such transformation does not mean the cells are cancerous.

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 two-stage model of carcinogenesis
• Who was studied: Rat pleural mesothelial cells from the parietal pleura of one Sprague-Dawley rat. Cultures at passage 12 were treated in triplicate in four series: BP only, DMSO then chrysotile, BP then chrysotile, and untreated control.
• Exposure: Benzo[a]pyrene at 1 microgram per ml once at passage 12. Rhodesian chrysotile fibres (UICC) given weekly from passage 13 to passage 40: 5 micrograms per ml (1 microgram per square cm) through passage 17, then 2 micrograms per ml (0.4 microgram per square cm) until passage 40.
• Main results:
  • Type III colonies were seen in the chrysotile-only (DMSO-Chr) and BP series from passage 22, and later (passage 29) in the BP-then-chrysotile series. In the untreated control series they appeared only at a low rate (5%) at passages 30 to 33 and were then no longer observed.
  • After passage 29, type III colonies rose to 55% in the BP series and roughly 35% in both chrysotile-treated series.
  • From passage 17, the chrysotile-only series had the highest percentage of type II colonies, at least until passage 29. The BP-then-chrysotile series did not differ from control for type II colonies.
  • No synergism was seen between BP and chrysotile, with no additive or multiplicative effect. The effect was somewhat decreased when cells received both.
  • When the BP series was treated with chrysotile at passages 38 to 40, the percentage of type III colonies decreased.
  • Chrysotile-treated series had lower cell numbers than control, which the authors related to the toxicity of chrysotile to the cells.
  • In a repeat experiment that included a DMSO-only series, the percentage of each colony type was identical to control, so the effect was attributed to chrysotile and not to DMSO.
• The authors' conclusion: The authors concluded that chrysotile fibres did not seem to act as a promoter of BP on rat pleural mesothelial cells, but that either chrysotile or BP induced morphological transformation. They suggested that type III colonies point to progression towards a neoplastic state.
• Limitations the authors state:
  • Morphological transformation does not mean the cells are neoplastic (cancerous).
  • The reduced effect when BP and chrysotile were combined could not be explained.
  • Increased cell density, seen in the BP series, is not a strongly reliable criterion of transformation.

Topics

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

Medical terms in this study, explained in our Lexicon: Mesothelial Cells, Chrysotile, Carcinogenesis, Synergistic Effect.

Related studies

• Chromosomal changes induced by chrysotile fibres or benzo-3,4-pyrene in rat pleural mesothelial cells — M.C. Jaurand, L. Kheuang, et al. (1986)
• Studies on in vitro chrysotile-pleural mesothelial cell interaction: morphological aspects and metabolism of benzo-3,4-pyrene — M.C. Jaurand, I. Bastie-Sigeac, et al. (1983)
• 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)
• Sister chromatid exchanges in rat pleural mesothelial cells treated with crocidolite, attapulgite, or benzo 3-4 pyrene — S. Achard, M. Perderiset, et al. (1987)
• Asbestos and benzo(a)pyrene synergism in the transformation of Syrian hamster embryo cells — J.A. DiPaolo, A.J. DeMarinis, et al. (1983)
• In vitro reactivity of alveolar macrophages and red blood cells with asbestos fibres treated with oxalic acid, sulfur dioxide and benzo-3,4-pyrene — M.C. Jaurand, L. Magne, et al. (1981)

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