Asbestos-enhanced uptake of carcinogens

Our plain-English summary of Asbestos-enhanced uptake of carcinogens, by W.G. Light (Nature, 1979).

The study

• Author: W.G. Light
• Journal: Nature
• Published: 1979;279(5711):349-50
• Type of article: Letter
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

This was a Nature correspondence item: a letter from Light commenting on an earlier report that particulates enhance uptake of the carcinogen benzo[a]pyrene (BP) into dipalmitoyl phosphatidylcholine (DPPC) vesicles, together with a reply from Lakowicz, Hylden and Bevan. Light presented no new experimental data or numbers. Light proposed that the increased rate of transfer of BP adsorbed to particulate silica or amosite asbestos, compared with microcrystalline BP, was principally a result of adsorption of mobile DPPC vesicles onto the particulate surface rather than increased solubilisation of BP in an aqueous phase, citing earlier work that DPPC adsorbs onto glass fibres and various types of asbestos, including amosite, through coulombic interactions with the particles' electrostatic charge. The reply stated that uptake kinetics of 1,2-benzanthracene into DPPC vesicles were virtually the same over a wide range of particle-to-DPPC ratios, and that in investigations then under way using natural membranes, namely rat liver microsomes and 3T3 cells, the particles again enhanced BP uptake, with asbestos more effective than silica. Light concluded that interfacial transfer of carcinogens at the particulate surface may be a factor in co-carcinogenesis; the reply stated the transfer mechanism had not been elucidated.

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: Correspondence (letter to the journal) proposing a mechanism, published with a reply from the authors of the original report; no new experiment is described by the letter writer
• Who was studied: No human or animal population; laboratory membrane systems only – DPPC vesicles, and, in investigations the reply says were under way, rat liver microsomes and 3T3 cells
• Exposure: Particulate amosite asbestos and silica (and glass fibres in cited adsorption work) carrying the polynuclear aromatic hydrocarbons benzo[a]pyrene (BP) and 1,2-benzanthracene; no doses given
• Main results:
  • Light proposed that the faster transfer of BP adsorbed to particulate silica or amosite asbestos (versus microcrystalline BP) comes mainly from adsorption of mobile DPPC vesicles onto the particle surface, not from increased solubilisation of BP in water
  • Light cited evidence that DPPC adsorbs onto glass fibres and various types of asbestos, including amosite, the adsorption being controlled by coulombic interactions with the particles' electrostatic charge
  • In the reply, the original authors stated they measured virtually the same uptake kinetics of 1,2-benzanthracene into DPPC vesicles over a wide range of particle-to-DPPC ratios, supporting their solubilisation explanation
  • In the reply, in investigations described as under way using rat liver microsomes and 3T3 cells, the particles enhanced BP uptake, with asbestos more effective than silica (no numbers given)
• The authors' conclusion: Light concluded that preferential interfacial transfer of carcinogens to cell membranes and/or lung surfactant at the particulate surface may be an important factor in co-carcinogenesis
• Limitations the authors state:
  • The authors of the reply stated that the mechanism of the transfer process had not been elucidated
  • The authors of the reply stated it was not known whether carcinogens adsorbed to particles are eluted during contact with surfactant or after subsequent contact with cells
  • The authors of the reply stated they did not intend to indicate that the particles can increase the equilibrium solubility of the PAH

Related studies

• Asbestos-enhanced uptake of carcinogens — J.R. Lakowicz, J.L. Hylden, et al. (1979)
• Asbestos-mediated membrane uptake of benzo[a]pyrene observed by fluorescence spectroscopy — J.R. Lakowicz, J.L. Hylden (1978)
• Transport of a carcinogen, benzo[a]pyrene, from particulates to lipid bilayers: a model for the fate of particle-adsorbed polynuclear aromatic hydrocarbons which are retained in the lungs — J.R. Lakowicz, D.R. Bevan, et al. (1980)
• Effects of crocidolite and chrysotile asbestos on cellular uptake and metabolism of benzo(a)pyrene in hamster tracheal epithelial cells — B.T. Mossman, A. Eastman, et al. (1983)
• Benzo[a]pyrene uptake into rat liver microsomes: effects of adsorption of benzo[a]pyrene to asbestos and non-fibrous mineral particulates — J.R. Lakowicz, D.R. Bevan (1980)
• Effects of asbetos, iron oxide, silica, and carbon black on the microsomal availability of benzo[a]pyrene — J.R. Lakowicz, D.R. Bevan (1979)

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