Fisetin inhibits human melanoma cell invasion through promotion of mesenchymal to epithelial transition and by targeting MAPK and NFκB signaling pathways

PLoS One. 2014 Jan 23;9(1):e86338. doi: 10.1371/journal.pone.0086338. eCollection 2014.

Abstract

Malignant melanoma is responsible for approximately 75% of skin cancer-related deaths. BRAF plays an important role in regulating the mitogen-activated protein kinase (MAPK) signaling cascade in melanoma with activating mutations in the serine/threonine kinase BRAF occurring in 60-70% of malignant melanomas. The BRAF-MEK-ERK (MAPK) pathway is a key regulator of melanoma cell invasion. In addition, activation of NFκB via the MAPK pathway is regulated through MEK-induced activation of IKK. These pathways are potential targets for prevention and treatment of melanoma. In this study, we investigated the effect of fisetin, a phytochemical present in fruits and vegetables, on melanoma cell invasion and epithelial-mesenchymal transition, and delineated the underlying molecular mechanism. Treatment of multiple human malignant melanoma cell lines with fisetin (5-20 µM) resulted in inhibition of cell invasion. BRAF mutated melanoma cells were more sensitive to fisetin treatment, and this was associated with a decrease in the phosphorylation of MEK1/2 and ERK1/2. In addition, fisetin inhibited the activation of IKK leading to a reduction in the activation of the NFκB signaling pathway. Treatment of cells with an inhibitor of MEK1/2 (PD98059) or of NFκB (caffeic acid phenethyl ester) also reduced melanoma cell invasion. Furthermore, treatment of fisetin promoted mesenchymal to epithelial transition in melanoma cells, which was associated with a decrease in mesenchymal markers (N-cadherin, vimentin, snail and fibronectin) and an increase in epithelial markers (E-cadherin and desmoglein). Employing three dimensional skin equivalents consisting of A375 cells admixed with normal human keratinocytes embedded onto a collagen-constricted fibroblast matrix, we found that treatment of fisetin reduced the invasive potential of melanoma cells into the dermis and increased the expression of E-cadherin with a concomitant decrease in vimentin. These results indicate that fisetin inhibits melanoma cell invasion through promotion of mesenchymal to epithelial transition and by targeting MAPK and NFκB signaling pathways.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigens, CD
  • Antineoplastic Agents, Phytogenic / pharmacology*
  • Cadherins / metabolism
  • Cell Line, Tumor
  • Cell Movement
  • Cell Nucleus / metabolism
  • Cell Transdifferentiation / drug effects*
  • Drug Screening Assays, Antitumor
  • Flavonoids / pharmacology*
  • Flavonols
  • Humans
  • MAP Kinase Signaling System*
  • Melanoma
  • NF-kappa B / metabolism
  • Neoplasm Invasiveness
  • Phosphorylation
  • Protein Processing, Post-Translational / drug effects
  • Protein Transport / drug effects
  • Vimentin / metabolism

Substances

  • Antigens, CD
  • Antineoplastic Agents, Phytogenic
  • CDH1 protein, human
  • Cadherins
  • Flavonoids
  • Flavonols
  • NF-kappa B
  • Vimentin
  • fisetin