1. Sodium hydrogen exchanger and phospholipase D are required for alpha1-adrenergic receptor stimulation of metalloproteinase-9 and cellular invasion in CCL39 fibroblasts.
- Author
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Taves J, Rastedt D, Canine J, Mork D, Wallert MA, and Provost JJ
- Subjects
- Adrenergic alpha-1 Receptor Agonists, Adrenergic alpha-Agonists pharmacology, Animals, Blotting, Western, Carcinoma, Non-Small-Cell Lung enzymology, Cell Line, Cell Line, Tumor, Cricetinae, Cricetulus, Electrophoresis, Polyacrylamide Gel, Enzyme Activation, Fibroblasts cytology, Fibroblasts drug effects, Fibroblasts enzymology, Fibroblasts metabolism, Glycerophospholipids biosynthesis, Humans, Lung Neoplasms enzymology, Neoplasm Invasiveness, Phenylephrine pharmacology, Phospholipase D antagonists & inhibitors, Carcinoma, Non-Small-Cell Lung pathology, Lung Neoplasms pathology, Matrix Metalloproteinase 9 metabolism, Phospholipase D metabolism, Receptors, Adrenergic, alpha-1 physiology, Sodium-Hydrogen Exchangers metabolism
- Abstract
Matrix metalloproteinase 9 (MMP-9) plays a critical role in digesting the extracellular matrix and has a vital function in tumor metastasis and invasion; this protease activity is significantly increased in non-small cell lung cancers. The sodium hydrogen exchanger isoform 1 (NHE1) functions as a focal point for signal coordination and cytoskeletal reorganization. NHE1 is thought to play a central role in establishing signaling components at the leading edge of a migrating cell. Therefore, we studied the relationship between NHE1 and MMP-9 activity in Chinese hamster lung fibroblasts (CCL39) stimulated with phenylephrine (PE). We show that PE increases MMP-9 gelatinolytic activity in CCL39 cells. The inhibition of phospholipase D (PLD) signaling abrogated PE-induced MMP-9 activity. The role of PLD as an essential signaling intermediate was confirmed when the addition of permeable phosphatidic acid increased MMP-9 activity in the same cells. PE-induced invasion was increased 1.9-fold over controls and the PE response was lost when 1-butanol was used to block PLD signaling. Cells pre-treated with the NHE1 inhibitor, 5-(N-ethyl-N-isopropyl) amiloride (EIPA) prior to PE addition resulted in a notable decrease in MMP-9 activation and cell invasion as compared to untreated PE-stimulated cells. CCL39 NHE1 null cells demonstrated no increase in MMP-9 protease activity or cell invasion in response to PE treatment. Reconstitution of NHE1 expression recovered the PE-induced activation of protease activity and cell invasion. MMP-9 processing was altered in cells expressing a proton transport defective NHE1 but retained the ability to respond to PE. Conversely, cells expressing an ezrin, radixin, moesin (ERM)-binding deficient NHE1 had a lower MMP-9 activity and the protease did not respond to PE addition. Parallel studies on NCI-H358 non-small cell lung cancer (NSCL) cells showed that PE stimulated both MMP-9 activity and cell invasion in an NHE1 dependent manner. This work describes for the first time a PE-induced relationship between NHE1 and MMP-9 and a new potential mechanism by which NHE1 could promote tumor formation and metastasis.
- Published
- 2008
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