title: The fungicide ciclopirox inhibits lymphatic endothelial cell tube formation by suppressing VEGFR-3-mediated ERK signaling pathway.
abstract: 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.
authors.affiliation: Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Luo
authors.forename: H
authors.initials: H
authors.lastname: Zhou
authors.forename: L
authors.initials: L
authors.lastname: Liu
authors.forename: T
authors.initials: T
authors.lastname: Shen
authors.forename: W
authors.initials: W
authors.lastname: Chen
authors.forename: B
authors.initials: B
authors.lastname: Xu
authors.forename: X
authors.initials: X
authors.lastname: Han
authors.forename: F
authors.initials: F
authors.lastname: Zhang
authors.forename: R S
authors.initials: RS
authors.lastname: Scott
authors.forename: J S
authors.initials: JS
authors.lastname: Alexander
authors.forename: A
authors.initials: A
authors.lastname: Alam
authors.forename: S
authors.initials: S
authors.lastname: Huang
mesh_terms: D000818:Animals; D000077768:Ciclopirox; D004727:Endothelium / Q000166:cytology / Q000187:drug effects*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D005659:Fungicides, Industrial / Q000633:toxicity*; D051379:Mice; D011728:Pyridones / Q000633:toxicity*; D015398:Signal Transduction / Q000187:drug effects*; D040321:Vascular Endothelial Growth Factor Receptor-3 / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D005659:Fungicides, Industrial; D011728:Pyridones; D000077768:Ciclopirox; D040321:Vascular Endothelial Growth Factor Receptor-3; D048049:Extracellular Signal-Regulated MAP Kinases