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Autocrine regulation of DU145 human prostate cancer cell growth by epidermal growth factor-related polypeptides
1Division of Nutrition and Endocrinology, Naylor Dana Institute for Disease Prevention, American Health Foundation, Valhalla, New York 10595.
Abstract:
The DU145 human prostate cancer cell line possesses epidermal growth factor (EGF) receptors and synthesizes both EGF and the related polypeptide transforming growth factor-alpha (TGF-alpha). A monoclonal antibody to the EGF receptor was used to determine whether these characteristics were indicative of a functional autocrine regulatory system. This antibody competed effectively with [125I]EGF for binding to DU145 cell binding sites over a 1 x 10(-11) to 1 x 10(-7) M concentration range, and did so with a capability similar to that of the two natural ligands. It inhibited growth of these cells in both 3% fetal bovine serum-supplemented and serum-free medium; in experiments with incubation times of 3-5 days there was a 45-50% reduction in cell number. Growth suppression by the EGF receptor blockade of cells plated at a density of 1.5 x 10(4) cells/ml/well was reversed competitively by the addition of EGF to the medium; 0.3 nM completely eliminated the inhibitory effect of a 1 x 10(-9) M antibody concentration. It is concluded that DU145 cell growth is regulated by an EGF-mediated autocrine loop.
Insights
DU145 prostate cancer cells utilize epidermal growth factor (EGF) in an autocrine loop for growth regulation. Blocking the EGF receptor with an antibody significantly inhibited cell proliferation, confirming this self-sustaining mechanism.
Area of Science:
- Oncology
- Cell Biology
- Molecular Endocrinology
Background:
- DU145 human prostate cancer cells express epidermal growth factor (EGF) receptors.
- These cells also synthesize EGF and transforming growth factor-alpha (TGF-alpha).
Purpose of the Study:
- To investigate if DU145 cells possess a functional autocrine regulatory system mediated by EGF.
- To determine the role of EGF signaling in DU145 cell proliferation.
Main Methods:
- Utilized a monoclonal antibody targeting the EGF receptor for competitive binding assays.
- Assessed the impact of EGF receptor blockade on DU145 cell growth in vitro.
- Investigated the reversibility of growth inhibition by adding exogenous EGF.
Main Results:
- The monoclonal antibody effectively competed with [125I]EGF for binding to DU145 cell receptors.
- EGF receptor blockade resulted in a 45-50% reduction in DU145 cell number within 3-5 days.
- Growth suppression was reversed by the addition of EGF, indicating a specific inhibitory mechanism.
Conclusions:
- DU145 cell growth is regulated by an autocrine loop involving EGF.
- The EGF receptor plays a critical role in mediating proliferation in this prostate cancer cell line.