title: Stanniocalcin-1 regulates extracellular ATP-induced calcium waves in human epithelial cancer cells by stimulating ATP release from bystander cells.
abstract: BACKGROUND
  The epithelial cell response to stress involves the transmission of signals between contiguous cells that can be visualized as a calcium wave. In some cell types, this wave is dependent on the release of extracellular trinucleotides from injured cells. In particular, extracellular ATP has been reported to be critical for the epithelial cell response to stress and has recently been shown to be upregulated in tumors in vivo.
  
  
  RESULTS
  Here, we identify stanniocalcin-1 (STC1), a secreted pleiotrophic protein, as a critical mediator of calcium wave propagation in monolayers of pulmonary (A549) and prostate (PC3) epithelial cells. Addition of STC1 enhanced and blocking STC1 decreased the distance traveled by an extracellular ATP-dependent calcium wave. The same effects were observed when calcium was stimulated by the addition of exogenous ATP. We uncover a positive feedback loop in which STC1 promotes the release of ATP from cells in vitro and in vivo.
  
  
  CONCLUSIONS
  The results indicated that STC1 plays an important role in the early response to mechanical injury by epithelial cells by modulating signaling of extracellular ATP. This is the first report to describe STC1 as a modulator or purinergic receptor signaling.
authors.affiliation: Institute for Regenerative Medicine at Scott and White Hospital, Texas A&M Health Sciences Center, Temple, Texas, United States of America.
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Block
authors.forename: Gabriel D
authors.initials: GD
authors.lastname: DiMattia
authors.forename: Darwin J
authors.initials: DJ
authors.lastname: Prockop
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism* / Q000494:pharmacology; D024201:Bystander Effect; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D045744:Cell Line, Tumor; D004847:Epithelial Cells / Q000378:metabolism / Q000473:pathology*; D025461:Feedback, Physiological; D006023:Glycoproteins / Q000502:physiology*; D006801:Humans; D015398:Signal Transduction
chemical_list: D006023:Glycoproteins; C051795:teleocalcin; D000255:Adenosine Triphosphate