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Effects of epidermal growth factor and phorbol ester on thyroid epithelial integrity
1Institute of Anatomy and Cell Biology, University of Göteborg, Sweden.
Experimental Cell Research
|August 1, 1995
Summary
Epidermal growth factor (EGF) promotes thyroid cell growth while maintaining barrier function. However, combined with phorbol ester (TPA), EGF causes lasting damage to thyroid epithelial integrity and cell adhesion.
Area of Science:
- Cell Biology
- Endocrinology
- Epithelial Biology
Background:
- Thyroid epithelial cells maintain specialized functions and integrity.
- Growth factors like EGF and TPA can influence cell behavior and tissue structure.
- Understanding their effects is crucial for thyroid biology research.
Purpose of the Study:
- To investigate the impact of epidermal growth factor (EGF) and phorbol ester (TPA) on thyroid epithelial integrity.
- To analyze cellular responses, barrier function, and cell-cell adhesion mechanisms.
- To determine the combined effects of EGF and TPA on thyroid cell monolayers.
Main Methods:
- Cultured porcine thyrocytes on filters to assess transepithelial resistance (RTE).
- Stimulation with EGF and TPA, measuring [3H]thymidine incorporation and DNA content.
- Analysis of ultrastructural polarity, ZO-1, cadherin distribution, and paracellular permeability ([3H]inulin).
Main Results:
- EGF stimulated DNA synthesis and proliferation, maintaining polarity and tight junctions but reducing cytoplasmic cadherin.
- TPA induced temporary barrier dysfunction, cytoskeletal changes, and cell shedding, with recovery over time.
- Combined EGF and TPA treatment resulted in persistent cell layer derangement, ZO-1 attenuation, and cell detachment.
Conclusions:
- EGF releases thyroid cells from growth inhibition, preserving polarity and tight junctions.
- EGF, in combination with TPA, induces lasting morphological changes and potential defects in Ca2+-dependent adhesion.
- The findings suggest a latent transforming potential in cadherin-based regulation under combined growth factor stimulation.
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