Distinct Intracellular pH (pHcyt) and Calcium ([Ca2+]cyt) Regulation in Human Melanoma Cells with Poor and High Invasive Potential

pH cyt and [Ca 2+ ] cyt play important roles in the regulation of several physiological and pathophysiological processes. We hypothesize that the transition from a poorly invasive to a highly invasive phenotype involve alterations in specific pH cyt and [Ca 2+ ] cyt regulatory systems, including the plasma membrane V‐ATPase (pmV‐ATPase) and the Na + /Ca 2+ exchanger (NCE). To test this hypothesis we used highly (C8161) and poorly (A375p) invasive human melanoma cells. These cells were loaded with intracellular pH and Ca 2+ fluoroprobes. Fluorescence was monitored using fluorescence based spectroscopy and optical approaches. Distribution of pmV‐ATPase and NCE was evaluated by immunocytochemistry and optical approaches. The significance of the distinct pH cyt and [Ca 2+ ] cyt regulatory systems for invasion/migration was evaluated using pharmacological approaches. Highly invasive cells exhibit greater proton fluxes ( J H+ ) via pmV‐ATPase than poorly invasive cells. Stimulation with agonists elicit increases in [Ca 2+ ] cyt that were mediated by NCE in highly but not in poorly invasive cells. Pharmacological approaches supported the relevance of pH cyt and Ca 2+ regulatory systems for cell invasion/migration. Altogether, our data indicated that highly invasive cells use pmV‐ATPase and NCE exchanger as important pH cyt and [Ca 2+ ] cyt regulatory mechanisms, needed for the transition to a more invasive phenotype. Supported by AHA‐GIA # 0555070Y to RMZ.