Eph-ephrin system plays a central role in a large variety of human cancers. In fact, alterated expression and/or de-regulated function of Eph-ephrin system promotes tumorigenesis and development of a more aggressive and metastatic tumour phenotype. In particular EphA2 upregulation is correlated with tumour stage and progression and the expression of EphA2 in non-trasformed cells induces malignant transformation and confers tumorigenic potential. Based on these evidences our aim was to identify small molecules able to modulate EphA2-ephrinA1 activity through an ELISA-based binding screening. We identified lithocholic acid (LCA) as a competitive and reversible ligand inhibiting EphA2-ephrinA1 interaction (Ki = 49 mu M). Since each ephrin binds many Eph receptors, also LCA does not discriminate between different Eph-ephrin binding suggesting an interaction with a highly conserved region of Eph receptor family. Structurally related bile acids neither inhibited Eph-ephrin binding nor affected Eph phosphorylation. Conversely, LCA inhibited EphA2 phosphorylation induced by ephrinA1-Fc in PC3 and HT29 human prostate and colon adenocarcinoma cell lines (IC(50) = 48 and 66 mM, respectively) without affecting cell viability or other receptor tyrosine-kinase (EGFR, VEGFR, IGFR1 beta, IRK beta) activity. LCA did not inhibit the enzymatic kinase activity of EphA2 at 100 mu M (LANCE method) confirming to target the Eph-ephrin protein-protein interaction. Finally, LCA inhibited cell rounding and retraction induced by EphA2 activation in PC3 cells. In conclusion, our findings identified a hit compound useful for the development of molecules targeting ephrin system. Moreover, as ephrin signalling is a key player in the intestinal cell renewal, our work could provide an interesting starting point for further investigations about the role of LCA in the intestinal homeostasis.

Lithocholic Acid Is an Eph-ephrin Ligand Interfering with Eph-kinase Activation / Giorgio C; Hassan Mohamed I; Flammini L; Barocelli E; Incerti M; Lodola A; Tognolini M.. - In: PLOS ONE. - ISSN 1932-6203. - e18128(2011). [10.1371/journal.pone.0018128]

Lithocholic Acid Is an Eph-ephrin Ligand Interfering with Eph-kinase Activation.

GIORGIO, Carmine;FLAMMINI, Lisa;BAROCELLI, Elisabetta;INCERTI, Matteo;LODOLA, Alessio;TOGNOLINI, Massimiliano
2011

Abstract

Eph-ephrin system plays a central role in a large variety of human cancers. In fact, alterated expression and/or de-regulated function of Eph-ephrin system promotes tumorigenesis and development of a more aggressive and metastatic tumour phenotype. In particular EphA2 upregulation is correlated with tumour stage and progression and the expression of EphA2 in non-trasformed cells induces malignant transformation and confers tumorigenic potential. Based on these evidences our aim was to identify small molecules able to modulate EphA2-ephrinA1 activity through an ELISA-based binding screening. We identified lithocholic acid (LCA) as a competitive and reversible ligand inhibiting EphA2-ephrinA1 interaction (Ki = 49 mu M). Since each ephrin binds many Eph receptors, also LCA does not discriminate between different Eph-ephrin binding suggesting an interaction with a highly conserved region of Eph receptor family. Structurally related bile acids neither inhibited Eph-ephrin binding nor affected Eph phosphorylation. Conversely, LCA inhibited EphA2 phosphorylation induced by ephrinA1-Fc in PC3 and HT29 human prostate and colon adenocarcinoma cell lines (IC(50) = 48 and 66 mM, respectively) without affecting cell viability or other receptor tyrosine-kinase (EGFR, VEGFR, IGFR1 beta, IRK beta) activity. LCA did not inhibit the enzymatic kinase activity of EphA2 at 100 mu M (LANCE method) confirming to target the Eph-ephrin protein-protein interaction. Finally, LCA inhibited cell rounding and retraction induced by EphA2 activation in PC3 cells. In conclusion, our findings identified a hit compound useful for the development of molecules targeting ephrin system. Moreover, as ephrin signalling is a key player in the intestinal cell renewal, our work could provide an interesting starting point for further investigations about the role of LCA in the intestinal homeostasis.
Lithocholic Acid Is an Eph-ephrin Ligand Interfering with Eph-kinase Activation / Giorgio C; Hassan Mohamed I; Flammini L; Barocelli E; Incerti M; Lodola A; Tognolini M.. - In: PLOS ONE. - ISSN 1932-6203. - e18128(2011). [10.1371/journal.pone.0018128]
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11381/2341150
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