The Eph tyrosine kinase receptors and their ephrin ligands play a central role in several human cancers and their deregulated expression or function promotes tumorigenesis, inducing aggressive tumor phenotypes. Green tea extracts (GTE) have been recently found to inhibit Eph-kinase phosphorylation. In order to evaluate the potential contribution of edible and medicinal plants on EphA2–ephrinA1 modulation, 133 commercially available plant extracts used as food supplements, essential and fixed oils were screened with an ELISA-based binding assay. Nine plant extracts, rich of polyphenols, reversibly inhibited binding in a dose-dependent manner (IC50 0.83–24 g/ml). Functional studies on PC3 prostate adenocarcinoma cells revealed that active extracts antagonized ephrinA1-Fc-induced EphA2-phosphorylation at non-cytotoxic concentrations (IC50 0.31–11.3 g/ml) without interfering with EGF-induced EGFR activation, suggesting a specific effect. These findings could furnish an interesting starting point regarding the potential relationship between diet, edible plant secondary metabolites and Eph–ephrin system, suggesting their possible involvement in cancer development modulation.
Polyphenol rich botanicals used as food supplements interfere with EphA2–ephrinA1 system
ROSSI, Damiano;POLI, Ferruccio;
2011
Abstract
The Eph tyrosine kinase receptors and their ephrin ligands play a central role in several human cancers and their deregulated expression or function promotes tumorigenesis, inducing aggressive tumor phenotypes. Green tea extracts (GTE) have been recently found to inhibit Eph-kinase phosphorylation. In order to evaluate the potential contribution of edible and medicinal plants on EphA2–ephrinA1 modulation, 133 commercially available plant extracts used as food supplements, essential and fixed oils were screened with an ELISA-based binding assay. Nine plant extracts, rich of polyphenols, reversibly inhibited binding in a dose-dependent manner (IC50 0.83–24 g/ml). Functional studies on PC3 prostate adenocarcinoma cells revealed that active extracts antagonized ephrinA1-Fc-induced EphA2-phosphorylation at non-cytotoxic concentrations (IC50 0.31–11.3 g/ml) without interfering with EGF-induced EGFR activation, suggesting a specific effect. These findings could furnish an interesting starting point regarding the potential relationship between diet, edible plant secondary metabolites and Eph–ephrin system, suggesting their possible involvement in cancer development modulation.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
