The tumor microenvironment and wound healing after injury, both contain extremely high concentrations of the extracellular signaling molecule, adenosine triphosphate (ATP) compared to normal tissue. P2Y2 receptor, an ATP-activated purinergic receptor, is typically associated with pulmonary, endothelial, and neurological cell signaling. Here we report its role and importance in breast epithelial cell signaling and how it’s altered in metastatic breast cancer. In response to ATP activation, P2Y2 receptor signaling causes an increase of intracellular Ca 2+ in non-tumorigenic breast epithelial cells, while their tumorigenic and metastatic counterparts have significantly reduced Ca 2+ responses. The non-tumorigenic cells respond to increased Ca 2+ with actin polymerization and localization to cellular junctions, while the metastatic cells remained unaffected. The increase in intracellular Ca 2+ after ATP stimulation could be blunted using a P2Y2 antagonist, which also prevented actin mobilization in non-tumorigenic breast epithelial cells. Furthermore, the lack of Ca 2+ concentration changes and actin mobilization in the metastatic breast cancer cells could be due to reduced P2Y2 expression, which correlates with poorer overall survival in breast cancer patients. This study elucidates rapid changes that occur after elevated intracellular Ca 2+ in breast epithelial cells and how metastatic cancer cells have adapted to evade this cellular response.
Statement of significance: This work shows non-tumorigenic breast epithelial cells increase intracellular Ca 2+ after ATP-P2Y2 signaling and re-localize actin, while metastatic cells lack this response, due to decreased P2Y2 expression, which correlates with poorer survival.