Cyclic nucleotide concentrations in asbestos-induced rat peritoneal mesothelioma

Our plain-English summary of Cyclic nucleotide concentrations in asbestos-induced rat peritoneal mesothelioma, by R.H. Stevens, L.A. Will, D.A. Cole, et al (Environmental Research, 1979).

The study

• Authors: R.H. Stevens, L.A. Will, D.A. Cole, E.S. Meek, C.W. Frank, K.J. Donham
• Journal: Environmental Research
• Published: 1979;19(2):442-8
• Cited by: 4 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Peritoneal mesotheliomas were induced through the intraperitoneal administration of Rhodesian chrysotile “A” to weanling male Holtzman rats. The intracellular concentrations of adenosine 3’,5’-cyclic monophosphate and guanosine 3’,5’-cyclic monophosphate were found to be significantly less than the levels measured in comparable control tissues obtained from age-matched animals that had been similarly administered charcoal instead of the asbestos. The calculated molar ratio of cAMP to cGMP was identical in tumors and control tissue implying that the two cyclic nucleotides were diminished by a constant factor in the tumor tissue. However, if tumorigenesis is related to cAMP/cGMP balance within the cancer cell, then in these apparently noninvasive lesions such an equilibrium exists as is found in cells of normal mesentery. These results indicate that asbestos-induced mesotheliomas are similar to other cancerous tissues of the digestive tract in that they contain less of the adenosine cyclic nucleotide than the normal tissue. The findings of this study suggest the possible loss of important cellular regulatory mechanisms in tumors induced by an important environmental carcinogen.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.

In plain English

This was an animal experiment. Young male Holtzman rats received a single 1 mg injection into the abdominal cavity of a standard reference sample of Rhodesian chrysotile "A" asbestos. Control rats of the same age were injected with 1 mg of charcoal instead. Within 6 months, the asbestos-injected rats developed visible tumors about 2 to 5 mm across at multiple sites throughout the peritoneum. Under the microscope these were mesotheliomas, made up mostly of spindle-shaped cells. The researchers measured two cell-signaling chemicals, cyclic AMP (cAMP) and cyclic GMP (cGMP), in tumor and control tissue, using 14 animals per group. Both were significantly lower in the tumors (p less than 0.01). Mean cAMP per milligram of protein was 123 (standard error 39) in controls and 29 (standard error 4) in tumors; the unit for the amount of cAMP is illegible in the scan. The ratio of cAMP to cGMP was the same in tumors and controls, which the authors read as an approximately fourfold drop in both. The authors concluded that the results indicate a loss of cellular regulators in the cancer cells and that further studies are needed.

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: induced peritoneal tumors in rats compared with charcoal-injected controls, with laboratory measurement of cyclic nucleotides
• Who was studied: Weanling male outbred Holtzman rats (University of Iowa laboratory). Controls were age-matched rats. Cyclic nucleotide measurements were made in 14 animals per group. Study dates are not given.
• Exposure: A single intraperitoneal injection of 1 mg of UICC standard reference Rhodesian chrysotile "A" in saline. Controls received 1 mg of Norite A charcoal by the same route.
• Main results:
  • In asbestos-injected rats, visible tumors about 2 to 5 mm in diameter developed at multiple sites throughout the peritoneum within 6 months. Histologically these were mesotheliomas, mostly spindle-shaped cells.
  • cAMP was significantly lower (P < 0.01) in the asbestos-induced tumors than in charcoal control tissue.
  • Figure 2 gives cAMP per milligram of protein as mean plus or minus standard error: 123 plus or minus 39 in charcoal controls (14 animals) and 29 plus or minus 4 in asbestos-induced tumors (14 animals). The unit for the amount of cAMP is not legible in the OCR.
  • cGMP was also significantly lower (P < 0.01) in the tumor tissue than in control tissue.
  • The molar ratio of cAMP to cGMP was identical in tumors and controls. The authors interpreted this as about a fourfold decrease in both nucleotides in the tumor tissue.
• The authors' conclusion: The authors concluded that the chrysotile-induced peritoneal mesotheliomas contained significantly less cAMP and cGMP than tissue from rats not injected with asbestos. In their view this indicates a loss of cellular regulators in the cancer cells, and further studies are needed to see whether systems controlled by these nucleotides are similarly affected.

Topics

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

Medical terms in this study, explained in our Lexicon: Peritoneal Mesothelioma, Chrysotile, Tumorigenesis, Mesentery, Mesothelioma.

Related studies

• Identification of carcinogens by measurement of cell-mediated immunity. III. Immunity to asbestos-induced rat peritoneal mesothelioma — D.A. Cole, R.H. Stevens, et al. (1982)
• Peroxisome proliferator-activated receptor-gamma ligands suppress fibronectin gene expression in human lung carcinoma cells: involvement of both CRE and Sp1 — S. Han, J.D. Ritzenthaler, et al. (2005)
• DNA fingerprint analysis reveals differences in mutational patterns in experimentally induced rat peritoneal tumors, depending on the type of environmental mutagen — N. Kociok, K. Unfried, et al. (1999)
• Malignant mesothelioma induced by asbestos and zeolite in the mouse peritoneal cavity — Y. Suzuki, N. Kohyama (1984)
• Hemizygosity of Nf2 is associated with increased susceptibility to asbestos-induced peritoneal tumours — J. Fleury-Feith, C. Lecomte, et al. (2003)
• Colonic invasion induced by malignant peritoneal mesothelioma — S.B. Cao, S. Jin, et al. (2014)

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