Extracellular nucleotide signaling in the human intestinal cell line Caco-2

BUZZI NATALIA; BOLAND RICARDO; RUSSO DE BOLAND ANA

Villa Carlos Paz

Congreso; XLIV Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2008

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB)

EXTRACELLULAR NUCLEOTIDE SIGNALING IN THE HUMAN INTESTINAL CELL LINE CACO-2 Natalia Buzzi, Ricardo Boland and Ana Russo de Boland Depto. Biología, Bioquímica y Farmacia. Universidad Nacional del Sur. Bahía Blanca, Argentina. The objective of this study was to examine the effects of exogenous ATP on the intracellular mitogen-activated protein kinase (MAPK) signaling pathways, in the human intestinal cell line Caco-2, which express functional P2Y and P2X receptors. The current study demonstrated that ATP activated ERK1/2, JNK1/2 and p38 MAPK in a dose- and time-dependent manner. PP2 (a c-Src inhibitor), Ro318220 (a PKC inhibitor), RpcAMP (a PKA inhibitor), significantly attenuated the ATP-induced activation of MAPKs. In Caco-2 cells, ATP rapidly modulates cytosolic calcium levels ([Ca2+]i), the cell Ca2+i response to the nucleotide was rapid and transient. In addition, activation of the MAPKs cascades by ATP was suppressed by the intracellular Ca2+ chelator BAPTA-AM, 2-APB, an IP3R inhibitor, or a Ca2+-free medium (EGTA). Furthermore, a marked inhibition of ATP-dependent JNK and p38 MAPK phosphorylation was observed in cells pretreated with the EGFR antagonist, AG1478. However, ERK activation by ATP, that was followed by its nuclear translocation, was slightly affected by the EGFR antagonist. All these findings indicate that extracellular ATP through purinergic stimulation or EGFR transactivation are effective regulators of the MAPK signaling pathways in the intestinal cell line Caco-2.