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Somatostatin inhibits rapid centrosomal separation and cell proliferation induced by epidermal growth factor
Abstract:
The role of endogenous growth inhibitors in the regulation of cell proliferation is unclear. Although there are numerous studies on the stimulatory effect of peptide hormones such as insulin, the somatomedins and epidermal growth factor (EGF) on cell proliferation, little is known about the existence of hormones that might exert an antiproliferative effect on cells. Somatostatin (SS), a cyclic tetradecapeptide hormone that is widely distributed in the body, exerts an inhibitory effect on numerous cellular processes. We observed that SS at concentrations of 10(-8) - 10(13M), inhibited EGF-induced centrosomal separation, which recent evidence suggests is necessary for DNA synthesis in response to EGF. This SS effect was associated with inhibition of DNA synthesis and cell replication induced by EGF in gerbil fibroma and HeLa cells. Inhibition of centrosomal separation and the consequent antiproliferative effect of SS may represent a biologically significant action of this ubiquitous hormone.
Insights
Somatostatin (SS) inhibits epidermal growth factor (EGF)-induced cell proliferation by blocking centrosomal separation, a key step for DNA synthesis. This finding reveals a significant antiproliferative role for this hormone.
Area of Science:
- Cell Biology
- Endocrinology
- Molecular Biology
Background:
- The role of endogenous growth inhibitors in regulating cell proliferation remains largely unknown.
- While stimulatory peptide hormones like insulin, somatomedins, and epidermal growth factor (EGF) are well-studied, antiproliferative hormones are less understood.
- Somatostatin (SS) is a widely distributed cyclic tetradecapeptide hormone known to inhibit various cellular processes.
Purpose of the Study:
- To investigate the potential antiproliferative effects of Somatostatin (SS) on cell growth.
- To determine if SS influences EGF-induced cell proliferation and DNA synthesis.
- To explore the mechanism by which SS might inhibit cell replication.
Main Methods:
- Gerbil fibroma and HeLa cells were treated with Somatostatin (SS) at varying concentrations (10^-8 - 10^-13M).
- The effect of SS on EGF-induced centrosomal separation was observed.
- DNA synthesis and cell replication rates were measured following EGF stimulation in the presence of SS.
Main Results:
- Somatostatin (SS) significantly inhibited EGF-induced centrosomal separation in both cell types.
- This inhibition of centrosomal separation by SS was correlated with a decrease in EGF-stimulated DNA synthesis.
- SS treatment led to the inhibition of cell replication induced by EGF.
Conclusions:
- Somatostatin (SS) exerts an antiproliferative effect on EGF-stimulated cell proliferation.
- Inhibition of centrosomal separation is a key mechanism through which SS exerts its antiproliferative action.
- This study highlights a potentially significant biological role for the ubiquitous hormone Somatostatin (SS) in regulating cell growth.