title: Resveratrol induces long-lasting IL-8 expression and peculiar EGFR activation/distribution in human keratinocytes: mechanisms and implications for skin administration.
abstract: Anti-inflammatory and skin tumour preventing effects of resveratrol have been extensively studied pre-clinically and resveratrol has been proposed for clinical investigations. To provide a basis or/and limitations for topical administration to human skin, molecular mechanisms underlying resveratrol effects towards normal human epidermal keratinocytes (NHEK) were evaluated. NHEK were challenged by either resveratrol alone or by its combination with TNFalpha or TGFalpha, and time-dependent molecular events were monitored. Interleukin 8 (IL-8) expression and its mRNA stability, ERK1/2, p65/RelA, and EGFR phosphorylation were determined. Intracellular distribution of EGFR/P-EGFR was measured in the membrane, cytoplasmic, and nuclear fractions. Specific DNA binding activity of NFκB (p65/RelA) and AP-1(c-Fos), NHEK proliferation, and molecular markers of apoptosis/cell cycle were detected. Resveratrol induced delayed, long-lasting and steadily growing IL-8 gene and protein over-expression as well as enhanced EGFR phosphorylation, both abrogated by the EGFR kinase inhibitor PD168393. However, resveratrol did not act as a phosphatase inhibitor. ERK phosphorylation was transiently inhibited at early time-points and activated at 6-24 h. Accordingly, c-Fos-specific DNA binding was increased by resveratrol. Cellular distribution of EGFR/P-EGFR was shifted to membrane and nucleus while cytosolic levels were reduced concomitant with enhanced degradation. Notwithstanding high nuclear levels of EGFR/P-EGFR, spontaneous and TGFalpha-triggered cell proliferation was strongly suppressed by resveratrol mainly through cell cycle arrest.
  
  
  CONCLUSIONS
  Resveratrol synergized with TNFα in the induction of delayed, long-lasting IL-8 expression through sustained EGFR-ERK axis activation. The time course indicates that resveratrol metabolites could be implicated. Topical administration of Resv to psoriatic patients over-expressing TNFα, IL-8 and EGFR-ERK in the skin should be cautiously considered. Since high nuclear levels of EGFR correspond to increased risk of tumorigenesis, chronic resveratrol application to the skin may be potentially dangerous. Wound healing acceleration by resveratrol could not be envisaged due to its anti-proliferative effects towards normal keratinocytes.
authors.affiliation: Lab Tissue Engineering and Skin Pathophysiology, Dermatology Institute, IDI IRCCS, Rome, Italy.
authors.forename: Saveria
authors.initials: S
authors.lastname: Pastore
authors.forename: Daniela
authors.initials: D
authors.lastname: Lulli
authors.forename: Riccardo
authors.initials: R
authors.lastname: Maurelli
authors.forename: Elena
authors.initials: E
authors.lastname: Dellambra
authors.forename: Chiara
authors.initials: C
authors.lastname: De Luca
authors.forename: Liudmila G
authors.initials: LG
authors.lastname: Korkina
mesh_terms: D000279:Administration, Cutaneous; D015153:Blotting, Western; D002453:Cell Cycle / Q000187:drug effects; D002462:Cell Membrane / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D003593:Cytoplasm / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay; D066246:ErbB Receptors / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects*; D005960:Glucosides / Q000494:pharmacology; D006801:Humans; D016209:Interleukin-8 / Q000378:metabolism*; D015603:Keratinocytes / Q000187:drug effects / Q000378:metabolism*; D010636:Phenols / Q000494:pharmacology; D010766:Phosphorylation; D060888:Real-Time Polymerase Chain Reaction; D000077185:Resveratrol; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013267:Stilbenes / Q000494:pharmacology*; D013997:Time Factors; D059808:Polyphenols
chemical_list: D017931:DNA Primers; D066246:ErbB Receptors; D005960:Glucosides; D016209:Interleukin-8; D010636:Phenols; D000077185:Resveratrol; D013267:Stilbenes; C058956:acteoside; D059808:Polyphenols