Carcinoma induction by 3-methylcholanthrene in hamster tracheal tissue implanted in syngeneic animals

Our plain-English summary of Carcinoma induction by 3-methylcholanthrene in hamster tracheal tissue implanted in syngeneic animals, by J.E. Craighead, B.T. Mossman (Progress in Experimental Tumor Research, 1979).

The study

• Authors: J.E. Craighead, B.T. Mossman
• Journal: Progress in Experimental Tumor Research
• Published: 1979;24:48-60
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

This 1979 animal experiment described the tumors that grew in hamster windpipe (tracheal) tissue exposed to the cancer-causing chemical 3-methylcholanthrene (3-MC). Tracheal tissue from inbred golden Syrian hamsters was exposed in one of two ways. In the first, 3-MC was coated onto iron oxide particles or crocidolite asbestos and placed on cultured tracheal tissue. In the second, 3-MC was coated onto a Lycra fiber inserted into an intact trachea. The tissue was then implanted under the skin of hamsters of the same inbred strain. In the cultured tissue, tumors appeared 3 to 17 months after exposure to 0.6 to 10 micrograms of 3-MC per graft. Of 67 tumors studied, all but 13 were carcinomas. The 13 others were fibrosarcomas. Most carcinomas were poorly differentiated. One small cell carcinoma was found. The authors cited their companion paper, not this one, for the finding that less 3-MC was needed with crocidolite than with iron oxide. The authors concluded that the 3-MC dose needed was substantially smaller than doses other investigators had used. This article did not report how many animals were used or describe asbestos-only exposures.

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: Animal experiment. Hamster tracheal tissue was exposed to 3-MC and implanted under the skin of genetically matched (syngeneic) hamsters. The report focuses on the microscopic features of the resulting tumors and early changes.
• Who was studied: Tracheal tissue from inbred golden Syrian hamsters (strain printed as BIO 15.16), supplied by TELACO, Bar Harbor, Maine. The work was done at the Department of Pathology, University of Vermont College of Medicine. The number of animals and the study dates are not given.
• Exposure: The chemical carcinogen 3-methylcholanthrene (3-MC), delivered on one of three carriers: iron oxide particles or crocidolite asbestos (UICC reference sample) placed on cultured tracheal tissue, or a Lycra fiber inserted into an intact trachea. A range of doses was tested.
• Main results:
  • In implanted cultured tracheal tissue, tumors developed 3 to 17 months after exposure to 3-MC at doses of 0.6 to 10 micrograms per graft.
  • Intact tracheal grafts containing Lycra fibers coated with more than 9 micrograms of 3-MC also developed tumors.
  • Of 67 tumors studied, all but 13 were carcinomas. The 13 exceptions were well-differentiated fibrosarcomas.
  • Sarcomas consistently developed in tissue exposed to relatively large doses of 3-MC.
  • The carcinomas were typically made up of poorly differentiated polygonal cells.
  • Small areas of keratinizing squamous carcinoma and mucin-secreting adenocarcinoma were occasionally found. One anaplastic small cell carcinoma was seen in a single tracheal graft.
  • In many specimens the poorly differentiated tumors were shown to arise from the respiratory lining (epithelium).
  • In implants that did not develop tumors, varying cell abnormalities and focal or extensive squamous metaplasia were seen.
  • The authors cited their accompanying paper (a separate article, not this one) as showing that more 3-MC was needed to induce tumors with iron oxide than with crocidolite.
• The authors' conclusion: The authors concluded that the 3-MC dose needed to induce epithelial tumors in their system was substantially smaller than the amounts other investigators had used. They also concluded that several different materials served as carriers for the carcinogen.
• Limitations the authors state:
  • The authors described their electron microscope study of the tumor cells as limited in scope.
  • The authors said the differences between their tumor types and those in earlier studies could be due to the model system or the dosage, and that these explanations could not be excluded.

Topics

Medical terms in this study, explained in our Lexicon: Carcinoma.

Related studies

• Use of hamster tracheal organ cultures for assessing the cocarcinogenic effects of inorganic particulates on the respiratory epithelium — B.T. Mossman, J.E. Craighead (1979)
• Tracheal carcinoma and mixed pneumoconiosis. A causal relationship? — D. Theegarten, S. Philippou, et al. (1995)
• Transfection of a manganese-containing superoxide dismutase gene into hamster tracheal epithelial cells ameliorates asbestos-mediated cytotoxicity — B.T. Mossman, P. Surinrut, et al. (1996)
• Interaction of asbestos with metaplastic squamous epithelium developing in organ cultures of hamster trachea — C.D. Woodworth, B.T. Mossman, et al. (1983)
• 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)
• Tests for effect of asbestos on benzo[a]pyrene carcinogenesis in the respiratory tract — L. Miller, W.E. Smith, et al. (1965)

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