Bradykinin promotes murine melanoma cell migration and invasion through endogenous production of superoxide and nitric oxide

Spatial confinement and temporal regulation of signaling by nitric oxide (NO) and reactive oxygen species (ROS) occurs in cancer cells. Signaling mediated by NO and ROS was investigated in two sub clones of the murine melanoma B16F10-Nex2 cell line, Nex10C and Nex8H treated or not with bradykinin (BK). The sub clone Nex10C, similar to primary site cells, has a low capacity for colonizing the lungs, whereas the sub clone Nex8H, similar to metastatic cells, corresponds to a highly invasive melanoma. BK-treated Nex10C cells exhibited a transient increase in NO and an inhibition in basal O-2(-) levels. Inhibition of endogenous NO production by L-NAME resulted in detectable levels of O-2(-). L-NAME promoted Rac1 activation and enhanced Rac1-PI3K association. L -NAME in the absence of BK resulted in Nex10C cell migration and invasion, suggesting that NO is a negative regulator of O-2(-) mediated cell migration and cell invasion. BK-treated Nex8H cells sustained endogenous NO production through the activation of NOS3. NO activated Rac1 and promoted Rac1-PI3K association. NO stimulated cell migration and cell invasion through a signaling axis involving Ras, Rac1 and PI3K. In conclusion, a role for O2-and NO as positive regulators of Rac1-PI3K signaling associated with cell migration and cell in-vasion is proposed respectively for Nex10C and Nex8H murine melanoma cells. (AU)