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Purinergic mechanisms in human bladder cancer cells
Author(s) -
Artim Debra E.,
Birder Lori A.,
de Groat William C.
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.21.6.a1349-b
Subject(s) - ppads , purinergic receptor , suramin , p2 receptor , p2y receptor , extracellular , thapsigargin , autocrine signalling , intracellular , receptor , calcium in biology , purinergic signalling , cancer cell , endocrinology , receptor antagonist , microbiology and biotechnology , medicine , chemistry , biology , antagonist , agonist , cancer , adenosine receptor
Bladder urothelial cells respond to purinergic (PUR) agonists with increased intracellular calcium (Ca ++ ) and release ATP in response to several stimuli. This study investigated PUR signaling in a human bladder cancer cell line (T24) using fura‐2AM to measure intracellular Ca ++ . ATP (100 uM) and UTP (50 uM) evoked a large increase in intracellular Ca ++ in >98% cells, but less than 10% of cells responded to αβ me‐ATP. The P 2 X receptor antagonist TNP‐ATP (10 uM) had no effect on the response to ATP in 90% of cells, while the combined P 2 X/P 2 Y receptor antagonist suramin (100 uM) blocked 50 – 90% of the response to both ATP and UTP, consistent with a response mediated primarily by P 2 Y receptors. Additionally, the non‐specific PUR receptor antagonist PPADS (100 uM) had variable effects; no effect in 40% of cells, ~50% inhibition of Ca ++ response in 40% of cells and >90% inhibition of Ca ++ response in 20% of cells, suggesting heterogeneity in the subtypes of PUR receptors expressed. Removing extracellular Ca ++ had little effect on responses to agonists, while 0.5 uM thapsigargin (TG) occluded the response to UTP, suggesting that the Ca ++ increase is due primarily to Ca ++ release from internal stores. Alone, TG increased intracellular Ca ++ and evoked ATP release from T24 cells. These results suggest that bladder cancer cells may retain their PUR signaling capabilities and that ATP may act as an autocrine factor in bladder cancer.