An early, nonrandom karyotypic change in immortal Syrian hamster cell lines transformed by asbestos: trisomy of chromosome 11

Our plain-English summary of An early, nonrandom karyotypic change in immortal Syrian hamster cell lines transformed by asbestos: trisomy of chromosome 11, by M. Oshimura, T.W. Hesterberg, J.C. Barrett (Cancer Genetics and Cytogenetics, 1986).

The study

• Authors: M. Oshimura, T.W. Hesterberg, J.C. Barrett
• Journal: Cancer Genetics and Cytogenetics
• Published: 1986;22(3):225-37
• Cited by: 66 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Cytogenetic studies were performed on eight early passage Syrian hamster embryo cell lines independently derived following asbestos exposure. The modal chromosome number of all the immortal cell lines was near-diploid. At the earliest passage examined, six of eight cell lines had only numerical chromosome changes. Cells in each of these six cell lines had an extra chromosome #11, either as a sole karyotypic change or with other numerical changes. The remaining two cell lines displayed both numerical and structural chromosome changes, but without involvement of chromosome #11. Common abnormalities were -X or -Y, +3, and 8p- in one cell line, and -13 and t(13;21) in the other cell line. A nonrandom gain of chromosome #8 was also found in four cell lines. In three of the four cell lines, trisomy of chromosome #8 seems to have occurred during karyotypic progression. The observation that nonrandom changes in chromosome number are an early karyotypic change after carcinogen treatment supports our hypothesis that induction of aneuploidy by asbestos is mechanistically important in the transformation of Syrian hamster embryo cells in culture and, further, suggests that trisomy 11 plays a major role in the early steps of immortalization and neoplastic progression.

In plain English

This was a laboratory study of hamster cells, not of people. The authors examined the chromosomes of eight Syrian hamster embryo cell lines, each established independently after the cells were treated with chrysotile asbestos. The lines had become immortal: they kept growing after normal cells stopped (senesced). They were generally not tumor-forming at early passages (before passage 20). In all lines the most common chromosome number was near-diploid. At the earliest passage examined, six of the eight lines showed only changes in chromosome number. All six had an extra chromosome 11 in every cell examined, sometimes as the only change. The other two lines had both numerical and structural changes that did not involve chromosome 11. An extra chromosome 8 was the most frequent additional change, seen in four lines. Most lines had more complicated chromosome patterns at later passages. Control cultures stayed diploid and showed no trisomy 11. The authors concluded that asbestos-induced aneuploidy (abnormal chromosome number) resulting in trisomy 11 may be mechanistically important early in the transformation of these cells.

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 cell culture study (cytogenetic analysis of asbestos-transformed hamster cell lines)
• Who was studied: Eight independently established Syrian hamster embryo cell lines. They were obtained either by cloning morphologically transformed colonies or by subculturing treated cells until the normal cells senesced, which generally occurred at passage 10. The lines were examined at various passages at the National Institute of Environmental Health Sciences, Research Triangle Park, NC.
• Exposure: Chrysotile asbestos applied to cells in culture at doses of 1-2 per square centimetre, described as doses that induced morphologic transformation. The unit symbol is garbled in the scan.
• Main results:
  • The immortalized cell lines were generally nontumorigenic at early passages (before passage 20).
  • In all eight cell lines, at every passage examined, the modal (most common) chromosome number was near-diploid.
  • Some cell lines had a small percentage of cells (2%-12%) with a chromosome number in the tetraploid range.
  • At the earliest passage examined, six of the eight lines had only numerical chromosome changes. All six had an extra chromosome 11 in all metaphases examined, either as the sole change or with other numerical changes.
  • The remaining two lines (ASB-203 at passage 15 and ASB-410 at passage 13) had both numerical and structural abnormalities that did not involve chromosome 11.
  • An extra chromosome 8 was the most frequent change seen in addition to the extra chromosome 11, found in four lines (ASB-205, ASB-403, ASB-404, ASB-406). Three of these four lines had both extra chromosomes in their modal karyotype.
  • Most cell lines had more complicated karyotypes at later passages.
  • Control mass cultures passaged until senescence remained diploid.
  • In colonies isolated from control cultures, no cells with trisomy 11 were observed.
• The authors' conclusion: The authors concluded that induction of aneuploidy by asbestos resulting in trisomy 11 may be mechanistically important in the early stages of asbestos-induced neoplastic transformation of Syrian hamster embryo cells in culture. They stated that their findings strongly indicate that trisomy 11 plays an important role in this transformation, at least in some cell lines.

Topics

Medical terms in this study, explained in our Lexicon: Asbestos Exposure.

Related studies

• Characterization of activated proto-oncogenes in chemically transformed Syrian hamster embryo cells — T.M. Gilmer, L.A. Annab, et al. (1988)
• Asbestos and benzo(a)pyrene synergism in the transformation of Syrian hamster embryo cells — J.A. DiPaolo, A.J. DeMarinis, 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)
• Karyotype analysis of tumorigenic human bronchial epithelial cells transformed by chrysolite asbestos using chemically induced premature chromosome condensation technique — M. Suzuki, C.Q. Piao, et al. (2001)
• In vitro cytotoxicity and transforming potential of industrial carbon dust (fibers and particles) in syrian hamster embryo (SHE) cells — C. Darne, F. Terzetti, et al. (2010)
• Detection of aneuploidy-inducing carcinogens in the Syrian hamster embryo (SHE) cell transformation assay — D.P. Gibson, M.J. Aardema, et al. (1995)

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