The fungicide ciclopirox inhibits lymphatic endothelial cell tube formation by suppressing VEGFR-3-mediated ERK signaling pathway

• Published in: Oncogene Vol. 30; no. 18; pp. 2098 - 2107
• Main Authors: LUO, Y, ZHOU, H, ALAM, A, HUANG, S, LIU, L, SHEN, T, CHEN, W, XU, B, HAN, X, ZHANG, F, SCOTT, R. S, ALEXANDER, J. S
• Format: Journal Article
• Language: English
• Published: Basingstoke Nature Publishing Group 05.05.2011
• Subjects: Animals; Antifungal agents; Antimicrobial agents; Antitumor agents; Biodegradation; Biological and medical sciences; Cancer; Cell growth; Cell physiology; Cell transformation and carcinogenesis. Action of oncogenes and antioncogenes; Ciclopirox; Ectopic expression; Endothelial cells; Endothelium; Endothelium - cytology; Endothelium - drug effects; Extracellular signal-regulated kinase; Extracellular Signal-Regulated MAP Kinases - metabolism; Fundamental and applied biological sciences. Psychology; Fungicides; Fungicides, Industrial - toxicity; Gene expression; Growth factor receptors; Health aspects; Kinases; Lymphatic system; MAP kinase; Mice; Molecular and cellular biology; mRNA; Nails; Phosphorylation; Physiological aspects; Protein biosynthesis; Protein kinase; Protein kinases; Proteins; Pyridones - toxicity; Signal transduction; Signal Transduction - drug effects; Skin; Vascular endothelial growth factor; Vascular Endothelial Growth Factor Receptor-3 - antagonists & inhibitors; Vascular Endothelial Growth Factor Receptor-3 - metabolism; Vascular endothelial growth factor receptors; United States; Endothelial cell; Extracellular signal-regulated protein kinase; Enzyme; Ciclopirox; Carcinogenesis; tube formation; Signal transduction; Antifungal agent; VEGFR-3; lymphatic endothelial cells; Inhibition; Vascular endothelial growth factor receptor 3; ERK
• ISSN: 0950-9232; 1476-5594
• DOI: 10.1038/onc.2010.590

Ciclopirox olamine (CPX), an off-patent antifungal agent used to treat mycoses of skin and nails, has recently been demonstrated to be a potential anticancer agent. However, the underlying mechanism is not well understood. Here, for the first time, we show that CPX inhibited lymphangiogenesis in an in vitro model (tube formation). This effect was, in part, associated with inhibition of vascular endothelial growth factor receptor-3 (VEGFR-3) expression, as overexpression of VEGFR-3 conferred partial resistance to CPX inhibitory effect on tube formation in lymphatic endothelial cells (LECs), whereas downregulation of VEGFR-3 mimicked the effect of CPX, blocking the tube formation. Further study revealed that CPX did not alter mRNA level, but inhibited protein synthesis and promoted protein degradation of VEGFR-3. In addition, we found that CPX inhibited phosphorylation of the extracellular signal-related kinase 1/2 (ERK1/2), a downstream effector of VEGFR-3. Overexpression of VEGFR-3 attenuated CPX inhibition of ERK1/2 phosphorylation, whereas downregulation of VEGFR-3 inhibited ERK1/2 phosphorylation in LECs. Ectopic expression of constitutively active mitogen-activated protein kinase kinase 1 (MKK1) resulted in activation of ERK1/2 and partially prevented CPX inhibition of LEC tube formation. The results suggest that CPX inhibits LEC tube formation at least, in part, through inhibiting VEGFR-3-mediated ERK signaling pathway.