[Ca2+]i as a potential downregulator of alpha2beta1-integrin-mediated A2058 tumor cell migration to type IV collagen.
We have investigated cellular Ca2+ regulation during A2058 human melanoma cell chemotaxis to type IV collagen (CIV). We have identified alpha2beta1-integrin as the primary mediator of A2058 cell response to CIV in vitro. Integrin ligation initiated a characteristic intracellular Ca2+ concentration ([Ca2+]i) response consisting of an internal release and a receptor-mediated Ca2+ entry. Thapsigargin (TG) pretreatment drained overlapping and CIV-inducible internal Ca2+ stores while initiating a store-operated Ca2+ release (SOCR). CIV-mediated Ca2+ entry was additive to TG-SOCR, suggesting an independent signaling mechanism. Similarly, ionophore application in a basal medium containing Ca2+ initiated a sustained influx. Elevated [Ca2+]i from TG-SOCR or ionophore significantly attenuated cell migration to CIV by recruiting the Ca2+/calcineurin-mediated signaling pathway. Furthermore, low [Ca2+]i induced by EGTA application in the presence of ionophore fully restored cell motility to CIV. Together, these results suggest that [Ca2+]i signaling accompanying A2058 cell response to alpha2beta1-integrin ligation is neither necessary nor sufficient and that elevated [Ca2+]i downregulates cell motility via a calcineurin-mediated mechanism in A2058 cell chemotaxis to CIV.
Hodgson
L
L
Department of Bioengineering, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Dong
C
C
D000911:Antibodies, Monoclonal / Q000378:metabolism; D000001:Calcimycin / Q000494:pharmacology; D019703:Calcineurin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D002614:Chelating Agents / Q000494:pharmacology; D002633:Chemotaxis / Q000187:drug effects / Q000502:physiology*; D003094:Collagen / Q000378:metabolism*; D016895:Culture Media, Serum-Free; D004533:Egtazic Acid / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D016023:Integrins / Q000378:metabolism*; D007476:Ionophores / Q000494:pharmacology; D008545:Melanoma; D038981:Receptors, Collagen; D019284:Thapsigargin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D002614:Chelating Agents; D016895:Culture Media, Serum-Free; D004791:Enzyme Inhibitors; D016023:Integrins; D007476:Ionophores; D038981:Receptors, Collagen; D000001:Calcimycin; D004533:Egtazic Acid; D019284:Thapsigargin; D003094:Collagen; D019703:Calcineurin; D002118:Calcium