Urokinase plasminogen activator receptor activation of invasion and migration in H460 cells requires Na+/H+ transporter activity and expression

Abstract

Non‐small cell lung cancer (NSCLC) is an aggressive cancer where 10% of patients survive beyond five years of initial diagnosis. One of the reasons for the poor survival rate is the robust invasion and metastatic properties of NSCLC. Urokinase plasminogen activator (uPA) and its receptor are directly associated with a poor prognosis in NSCLC. Na+/H+ transporter (NHE1) has been implicated in regulation of cell motility in a number of cancer cells. We wished to identify the role NHE1 plays in uPA activation of tumor progression in NSCLC. We used both uPA and the inactive‐receptor binding amino terminal fragment of uPA (ATF) to stimulate human lung H460 carcinoma cells. 10 nM uPA or ATF stimulated proliferation 1.4 ‐ 1.2 fold over non‐treated cells. Inhibition of NHE1 with 10 μM EIPA abrogated agonist‐stimulated proliferation. Tumor formation size and number was significantly increased by addition of either uPA or ATF, while NHE1 inhibition blocked the ability of either agonist to induce tumors in soft agar assays. Migration of H460 cells was inhibited in the presence of EIPA. Both uPA and ATF enhanced MMP9 activity but not in cells treated with EIPA. Only ATF increased MMP9 expression. We also show the effect of uPA in NHE1 and uPAR knockdown cell lines where we investigated MMP9 activity, and the location of NHE1 and uPAR in lipid rafts. Our results indicate that uPAR activation of cancer cell properties requires NHE1. Support from NIH‐1‐R15‐CA135616‐01