“Differential Modulation of Transcription Factors by ATP in Breast Cancer and Osteoblastic Cells”

KATZ SEBASTIÁN,; SCODELARO BILBAO, PAOLA GABRIELA; RUSSO DE BOLAND, ANA; BOLAND, RICARDO; SANTILLÁN, GRACIELA

Capital Federal

Congreso; XXIV Reunión Anual de la Asociación Argentina de Osteología y Metabolismo Mineral; 2007

Asociación Argentina de Osteología y Metabolismo Mineral

Previously, we supported the expression of P2Y2 subtype receptor in MCF-7 and ROS 17/2.8 cells, by RT-PCR studies. ATP/UTP P2Y2 receptor stimulation increased intracellular calcium levels ([Ca2+]i) by activation of PI-PLC/IP3 pathway and phosphorylated ERK1/2, p38 and p46 JNK MAPKs in MCF-7 breast cancer and osteoblastic ROS 17/2.8 osteosarcoma cells. We showed the participation of [Ca2+]i and PKC in MAPKs activation by ATP; moreover, mechanical stimulation after P2Y2 receptor activation induced a transient Ca2+ influx (ATP-dependent SAC influx) in both cell lines. This influx mediated the phosphorylation of MAPKs only in ROS 17/2.8 cells. In the present work, we studied the modulation of the transcription factors ATF1, CREB, cJun and JunD by ATP in both cell lines and evaluated the contribution of ATP-dependent SAC influx in such modulation in ROS 17/2.8 cells. Western blot analysis showed that ATP (5-10µM) stimulated ATF1, CREB and JunD phosphorylation after 15 min treatment in MCF-7 cells, whereas only ATF1 was activated after 5 min in ROS 17/2.8 cells. Otherwise, c-fos and c-jun expression was induced in the osteoblastic cells within 30 min and one hour of cell treatment with ATP, respectively. Cell incubation for 2-3 min with 2.5–5 mM Gd3+, which showed to inhibit ATP-dependent SAC influx, reduced c-fos and c-jun expression and ATF1 phosphorylation induced by ATP in ROS17/2.8 cells. These results suggest that P2Y2 receptor stimulation by ATP modulates in a cell type dependent manner ATF1, CREB, c-fos, c-Jun and JunD activation and expression. In addition, participation of ATP-dependent SAC influx in this regulation was observed in the osteoblastic cell line.