A new insight into the histogenesis of 'mesodermomas'--malignant mesotheliomas

Our plain-English summary of A new insight into the histogenesis of 'mesodermomas'--malignant mesotheliomas, by A. Donna, P.G. Betta, V. Bianchi, et al (Histopathology, 1991).

The study

• Authors: A. Donna, P.G. Betta, V. Bianchi, M. Ribotta, D. Bellingeri, F. Robutti, A. Marchesini
• Journal: Histopathology
• Published: 1991;19(3):239-44
• Cited by: 16 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

A myogenic phenotype was induced in cultures of human mesothelial cells treated for 72 h with atrazine, a triazine derivative. Immunoreactivity for both myosin and myoglobin was detected in a large number of these cells, irrespective of their polygonal or spindle morphology, whereas no expression of desmin was observed. These findings support the embryological identity of mesothelium and mesoderm, the former being, in the post-embryonic stage, potentially capable of differentiation along the same lineages which the latter normally displays during embryogenesis. In the light of this concept it can be assumed that primary malignancies arising from the mesothelium have the competence to express the pluripotent nature of embryonic mesoderm, and hence the term mesodermoma is appropriate for this group of tumours, including mesotheliomas in a classical sense. A postulated mechanism for the phenotypic change of mesothelial cells is also outlined, involving atrazine conversion to 5-aza-chloro-cytidine, a probable DNA hypomethylating and gene activating agent, like its analogue 5-azacytidine.

In plain English

This laboratory study tested whether normal human mesothelial cells (the lining cells from which mesothelioma arises) can take on muscle-like features. The authors grew cells from two lines, one from the normal mesothelium of a newborn and one from an adult hernial sac. They exposed the cells to the herbicide atrazine for 72 hours, alongside untreated cultures. Asbestos was not tested. It appears only as background: one author had earlier proposed that herbicides might drive sarcoma-like changes in mesotheliomas in farming areas near asbestos industries. Staining found skeletal fast myosin, a muscle protein, in approximately 75% of treated cells and myoglobin in almost all treated cells. Untreated cells showed neither. No cells, treated or untreated, showed desmin, another muscle marker. The authors concluded that normal as well as malignant mesothelium appears to consist of pluripotent cells similar to embryonic mesoderm, supporting their term "mesodermoma" for these tumours. As a hypothesis, they proposed that atrazine acts through conversion to 5-aza-chloro-cytidine, a probable DNA hypomethylating agent.

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-culture experiment with untreated control cultures
• Who was studied: Human peritoneal mesothelial cells from two previously established cell lines, one from the normal mesothelium of a newborn and one from an adult hernial sac
• Exposure: The herbicide atrazine (a triazine derivative) at 5 micromolar, added to the culture medium from the start; cells were stained at 72 hours. Asbestos was not an exposure in this experiment.
• Main results:
  • Skeletal fast myosin was found in approximately 75% of atrazine-treated cells, whatever their shape.
  • Untreated mesothelial cells did not express skeletal fast myosin.
  • Myoglobin was found in almost all atrazine-treated cells, whatever their shape.
  • Untreated mesothelial cells did not react for myoglobin.
  • Neither treated nor untreated cells showed desmin.
  • Some of the treated cells became spindle-shaped, while untreated cells and the rest of the treated cells were mostly large and flat.
• The authors' conclusion: The authors concluded that their hypothesis appears valid: mesothelium, normal as well as neoplastic, consists of pluripotent cells similar to embryonic mesoderm. They proposed, as a hypothetical mechanism, that atrazine is converted to 5-aza-chloro-cytidine, a possible DNA hypomethylating agent.
• Limitations the authors state:
  • The authors found the lack of desmin unexpected. They suggested desmin might have been present at levels too low for their staining method to detect, and described the muscle phenotype as only partially expressed.

Topics

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

Medical terms in this study, explained in our Lexicon: Malignant Mesothelioma, Mesothelial Cells, Desmin, Mesothelium, Mesoderm, Mesothelioma.

Related studies

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• Investigating palygorskite's role in the development of mesothelioma in southern Nevada: Insights into fiber-induced carcinogenicity — D. Larson, A. Powers, et al. (2016)
• Mesodermomas: a new embryological approach to primary tumours of coelomic surfaces — A. Donna, P.G. Betta (1981)
• Immunohistochemical evidence of the mesothelial histogenesis of a uterine adenomatoid tumor — Y. Satoh, M. Hiraguchi, et al. (1998)
• Embryonic ultrastructure as a guide in the diagnosis of tumors — G.R. Dickersin (1987)
• US mesothelioma patterns 1973-2002: indicators of change and insights into background rates — M.J. Teta, P.J. Mink, et al. (2008)

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