KMUP-1 INHIBITS H441 LUNG EPITHELIAL CELL GROWTH, MIGRATION AND PROINFLAMMATION VIA INCREASED NO/CGMP AND INHIBITED RHO KINASE/VEGF SIGNALING PATHWAYS

This study investigates whether KMUP-1 protects soluble guanylate cyclase (sGC) and inhibits vascular endothelial growth factor (VEGF) expression in lung epithelial cells in hypoxia, therapeutically targeting epithelial proinflammation. H441 cells were used as a representative epithelial cell line to examine the role of sGC and VEGF in hypoxia and the anti-proinflammatory activity of KMUP-1 in normoxia. Human H441 cells were grown in hypoxia for 24-72 h. KMUP-1 (1, 10, 100 mu M) arrested cells at the G0/G1 phase of the cell cycle, reduced cell survival and migration, increased p21/p27, restored eNOS, increased soluble guanylate cyclase (sGC) and PKG and inhibited Rho kinase II (ROCK-II). KMUP-1 (0.001-0.1 mu M) concentration dependently increased eNOS in normoxia and did not inhibit phosphodiesterase-5A (PDE-5A) in hypoxic cells. Hypoxia-induced factor-1 alpha (HIF-1 alpha) and VEGF were suppressed by KMUP-1 but not by L-NAME (100 mu M). The PKG inhibitor Rp-8-CPT-cGMPS (10 mu M) blunted the inhibition of ROCK-II by KMUP-1. KMUP-1 inhibited thromboxane A2-mimetic agonist U46619-induced PDE-5A, TNF-alpha (100 ng/ml)-induced iNOS, and ROCK-II and associated phospho-p38 MAPK, suggesting multiple anti-proinflammatory activities. In addition, increased p21/p27 by KMUP-1 at higher concentrations might contribute to an increased Bax/Bcl-2 and active caspase-3/procaspase3 ratio, concomitantly causing apoptosis. KMUP-1 inhibited ROCK-II/VEGF in hypoxia, indicating its anti-neoplastic and anti-inflammatory properties. KMUP-1 inhibited TNF-alpha-induced iNOS and U46619-induced PDE-5A and phospho-p38 MAPK in normoxia, confirming its anti-proinflammatory action. KMUP-1 could be used as an anti-proinflammatory agent to reduce epithelial inflammation.