Abstract
Sprouty proteins are potent receptor tyrosine kinase inhibitors that antagonize growth factor signaling and are involved in lung development. However, little is known about the regulation or targets of Sprouty-4 (Spry4) in lung cancer. Our study aimed to determine the role of Spry4 in non-small cell lung cancer (NSCLC). We found that Spry4 mRNA expression was decreased in NSCLC cell lines and in dysplastic lung cell lines compared with a nontransformed cell line, suggesting that Spry4 has tumor-suppressing activity. When Spry4 was stably transfected into H157 and H2122 NSCLC cell lines, decreased migration and invasion were observed. Matrix metalloproteinase-9 activity was decreased, and the expression of matrix metalloproteinase inhibitors TIMP1 and CD82 were increased. Stable expression of Spry4 led to reduced cell growth and reduced anchorage-independent growth in NSCLC cell lines, along with upregulation of tumor suppressors p53 and p21. Changes in epithelial and mesenchymal markers indicated that Spry4 expression induces a reversal of the epithelial to mesenchymal transition characteristic of tumor cells. Treatment of a nontransformed lung epithelial cell line with short hairpin RNA to Spry4 led to the decreased expression of epithelial markers and increased cell growth, supporting the concept of Spry4 acting as a tumor suppressor. We showed that the activity of the Spry4 promoter is increased by Wnt7A/Fzd9 signaling through peroxisome proliferator-activated receptor gamma. These data present previously undescribed targets of Spry4 and suggest that Spry4 is a downstream target of Wnt7A/Fzd 9 signaling. Spry4 may have efficacy in the treatment of NSCLC.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Carcinoma, Non-Small-Cell Lung / genetics*
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Carcinoma, Non-Small-Cell Lung / metabolism
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Carcinoma, Non-Small-Cell Lung / pathology
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Cell Line
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Cell Line, Tumor
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Cell Migration Inhibition / genetics
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Cell Migration Inhibition / physiology*
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Cell Movement / genetics*
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Cell Proliferation
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Cell Transformation, Neoplastic / genetics
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Cell Transformation, Neoplastic / metabolism
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Cell Transformation, Neoplastic / pathology*
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Epithelial Cells / pathology
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Frizzled Receptors / physiology
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Growth Inhibitors / genetics
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Growth Inhibitors / metabolism
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Growth Inhibitors / physiology*
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Humans
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Intracellular Signaling Peptides and Proteins / genetics
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Intracellular Signaling Peptides and Proteins / metabolism
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Intracellular Signaling Peptides and Proteins / physiology*
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Lung Neoplasms / genetics*
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Lung Neoplasms / metabolism
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Lung Neoplasms / pathology
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Mesoderm / pathology
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Neoplasm Invasiveness / genetics
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Nerve Tissue Proteins / genetics
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Nerve Tissue Proteins / metabolism
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Nerve Tissue Proteins / physiology*
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PPAR gamma / genetics
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PPAR gamma / metabolism
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PPAR gamma / physiology*
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Receptors, G-Protein-Coupled / physiology
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Signal Transduction / genetics
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Tumor Suppressor Proteins / genetics
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Tumor Suppressor Proteins / metabolism
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Tumor Suppressor Proteins / physiology
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Wnt Proteins / genetics
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Wnt Proteins / metabolism
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Wnt Proteins / physiology*
Substances
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FZD9 protein, human
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Frizzled Receptors
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Growth Inhibitors
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Intracellular Signaling Peptides and Proteins
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Nerve Tissue Proteins
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PPAR gamma
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Receptors, G-Protein-Coupled
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SPRY4 protein, human
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Tumor Suppressor Proteins
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WNT7A protein, human
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Wnt Proteins