Details

Autor(en) / Beteiligte

• Leone, Vincenza
• Palma, Antonella di
• Ricchi, Paolo
• Acquaviva, Fabio
• Giannouli, Maria
• Prisco, Anna Maria Di
• Iuliano, Francesca
• Acquaviva, Angela M

Titel

PGE^sub 2^ inhibits apoptosis in human adenocarcinoma Caco-2 cell line through Ras-PI3K association and cAMP-dependent kinase A activation

Ist Teil von

• American journal of physiology: Gastrointestinal and liver physiology, 2007-10, Vol.293 (4), p.G673

Ort / Verlag

Bethesda: American Physiological Society

Erscheinungsjahr

2007

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• PGE... plays a critical role in colorectal carcinogenesis. We have previously shown that COX-2 expression and PGE... synthesis are mediated by IGF-II/IGF-I receptor signaling in the Caco-2 cell line and that the pathway of phosphatidylinositol 3-kinase (PI3K)/Akt protects the cell from apoptosis. In the present study, we demonstrate that PGE... has the ability to increase Ras and PI3K association and decrease the level of apoptosis in the same experimental system. The effect of PGE... on PI3K/Ras association is dependent on the activation of EP4 receptor, the increase of cAMP levels, and the activation of PKA. In fact, treatment of cells with the PKA inhibitor H89 decreases the association of Ras and PI3K and Ras-associated PI3K activity. PKA inhibitor H89 is able to decrease threonine phosphorylation of Akt and to increase serine phosphorylation of Akt by p38 MAPK and counteracts the cytoprotective effect induced by PGE... In addition, PGE... is able to activate p38 MAPK and the inhibition of p38 MAPK, with SB203580 specific inhibitor or with dominant negative MKK6 kinase, is able to revert the apoptotic effect of H89 and serine phosphorylation of Akt. The effect of PGE... on Caco-2 cell survival through PKA activation is mediated and regulated by the balance of threonine/serine phosphorylation of Akt by p38 kinase and PI3K. In conclusion, our data elucidate a novel mechanism for regulation of colon cancer cell survival and provide evidences for new combinatory treatments of colon cancer. (ProQuest: ... denotes formulae/symbols omitted.)