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Orthotopic Implantation and Peripheral Immune Cell Monitoring in the II-45 Syngeneic Rat Mesothelioma Model
Published on: October 2, 2015
Expression of growth factor and growth factor receptor RNA in rat pleural mesothelial cells in culture
E Bermudez1, J Everitt, C Walker
1Chemical Industry Institute of Toxicology, Research Triangle Park, North Carolina 27709.
Abstract:
Mineral fiber-induced pleural mesothelioma in the rat is a suitable model for asbestos-induced mesothelioma in humans. A proposed mechanism for the genesis of mesotheliomas is the initiation of an autocrine pathway leading to unregulated growth of the mesothelium. To understand if changes in the expression of mRNA of critical growth factors and receptors occur in target mesothelial cells, it is first necessary to characterize the pattern of expression of these genes in normal mesothelial cells. Rat mesothelial cells were isolated from the parietal pleura and strains of these cells were propagated in vitro. The cells were diploid, had epithelial gross morphology and ultrastructure, and coexpressed keratins and vimentin. Northern blot analysis demonstrated that the cells expressed transforming growth factor beta 1 and fibroblast growth factor. Transcripts for transforming growth factor alpha, platelet-derived growth factor A-chain, and platelet-derived growth factor B-chain were not detected. Receptors for platelet-derived growth factor, epidermal growth factor, and insulin were detected. Although normal mesothelial cells express receptors for these growth factors, no production of their corresponding ligands by these cells could be detected, suggesting that autocrine stimulation of growth via the production of such factors may be specific to transformed mesothelial cells.
Insights
Normal rat mesothelial cells express growth factor receptors but not ligands, suggesting autocrine growth stimulation is specific to transformed cells. This finding is crucial for understanding mineral fiber-induced pleural mesothelioma.
Area of Science:
- Oncology
- Cell Biology
- Toxicology
Background:
- Mineral fibers, like asbestos, can induce pleural mesothelioma.
- Autocrine pathways are implicated in the unregulated growth of mesothelial cells leading to mesothelioma.
- Understanding gene expression in normal mesothelial cells is key to elucidating mesothelioma pathogenesis.
Purpose of the Study:
- To characterize the expression pattern of growth factors and their receptors in normal rat mesothelial cells.
- To investigate the potential for autocrine growth stimulation in non-transformed mesothelial cells.
Main Methods:
- Isolation and in vitro propagation of rat mesothelial cells from parietal pleura.
- Northern blot analysis to detect mRNA expression of specific growth factors and receptors.
- Characterization of cell morphology and protein expression (keratins, vimentin).
Main Results:
- Normal mesothelial cells expressed transforming growth factor beta 1 and fibroblast growth factor mRNA.
- Transcripts for transforming growth factor alpha, platelet-derived growth factor A-chain, and B-chain were not detected.
- Receptors for platelet-derived growth factor, epidermal growth factor, and insulin were detected.
Conclusions:
- Normal mesothelial cells express receptors for key growth factors but do not produce the corresponding ligands.
- Autocrine growth stimulation may be a mechanism specific to transformed mesothelial cells in mesothelioma development.
- This study provides a baseline for understanding gene expression changes in mesothelioma pathogenesis.
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