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ATP‐dependent SAC influx does not participate in ATP modulation of MAPKs in MCF‐7 human breast cancer cell line
Author(s) -
Bilbao Paola Scodelaro,
Boland Ricardo,
Santillán Graciela
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a626-b
Subject(s) - egta , purinergic receptor , intracellular , kinase , chemistry , p38 mitogen activated protein kinases , stimulation , microbiology and biotechnology , protein kinase a , biophysics , extracellular , biochemistry , calcium , biology , endocrinology , organic chemistry
This study investigates the modulation of mitogen‐activated protein kinases (MAPKs) ERK1/2, p38 and JNK1/2 and its relationship to changes in intracellular Ca 2+ concentration ([Ca 2+ ] i ) induced by ATP in breast cancer MCF‐7 cells. ATP, UTP but not ADP (5–10 μM) increased [Ca 2+ ] i by cation release from inner stores as determined by spectrofluorometry measurements in a Ca 2+ free medium (+0.5 mM EGTA). Slightly different responses were observed in medium with 1.5 mM Ca 2+ , indicating that Ca 2+ release is the main component in this purinergic response. Moreover, ATP or UTP but not ADP stimulation sensitized cells to mechanical stress leading to Ca 2+ influx. This mechanical stress activated Ca 2+ (SAC) influx was inhibited by 10 mM Gd 3+ . These data suggest that SAC influx is dependent on P2Y2 receptor activation. Western blot analysis showed that ERK1/2, p38 and JNK1 were rapidly (5 min) phosphorylated by 5 μM ATP, whereas the JNK2 isoform was activated after 15 min treatment with ATP. Activation of MAPKs was reduced by the use of 1 mM neomycin and 150 mM 2‐APB, whereas the use of a Ca 2+ free medium (+ 0.5 mM EGTA) or 10 mM Gd 3+ , a SAC channel inhibitor, had no effects. These results evidence an ATP‐dependent SAC influx in MCF‐7 cells which, differently to other cell types (Santillán and col., 2006), does not participate in modulation of MAPKs by ATP, effect only dependent on PI‐PLC/IP 3 /Ca 2+ release.