α-Melanocyte-stimulating Hormone Reduces Impact of Proinflammatory Cytokine and Peroxide-generated Oxidative Stress on Keratinocyte and Melanoma Cell Lines

doi:10.1074/jbc.275.21.15629

α-Melanocyte-stimulating Hormone Reduces Impact of Proinflammatory Cytokine and Peroxide-generated Oxidative Stress on Keratinocyte and Melanoma Cell Lines*

From the ^‡University Section of Medicine, Division of Clinical Sciences, Northern General Hospital, Sheffield S5 7AU, United Kingdom, ^¶Department of Clinical Chemistry, Northern General Hospital, Sheffield S5 7AU, United Kingdom, ^‖Laboratory of Oncology and Experimental Surgery, Institut Bordet, Université Libre de Bruxelles, B-1000 Brussels, Belgium, and the ^**University Department of Opthalmology and Orthoptics, Royal Hallamshire Hospital, Sheffield, S10 2JF, United Kingdom

Abstract

We have previously shown that α-melanocyte-stimulating hormone (α-MSH) can oppose tumor necrosis factor α activation of NF-κB (1–2 h) and intercellular adhesion molecule 1 up-regulation (mRNA by 3 h and protein by 24 h) in melanocytes and melanoma cells. The present study reports on the ability of four MSH peptides to control intracellular peroxide levels and glutathione peroxidase (GPx) activity in pigmentary and nonpigmentary cells. In human HBL melanoma and HaCaT keratinocytes tumor necrosis factor α and H₂O₂ both activated GPx in a time- and concentration-dependent manner (by 30–45 min). α-MSH peptides were found to inhibit the stimulated GPx activity and had biphasic dose-response curves. MSH 1–13 and MSH [Nle₄-d-Phe₇] achieved maximum inhibition at 10⁻¹⁰ and 10⁻¹² m, respectively. Higher concentrations (10–100 fold) of MSH 4–10 and MSH 11–13 were required to produce equivalent levels of inhibition. α-MSH was also capable of reducing peroxide accumulation within 15 min, and again this inhibition was biphasic. The data support a role of α-MSH in acute protection of cells to oxidative/cytokine action that precedes NF-κB and GPx activation. The rapidity and potency of the response to α-MSH in pigmentary and nonpigmentary cells suggest this to be a central role of this peptide in cutaneous cells.

Footnotes

↵* This work was supported by registered Charity No. 226678, Grant 87762 from the Special Trustees for the Former United Sheffield Hospitals, Sheffield, UK.The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵§ To whom correspondence should be addressed. Tel.: 44-114-2714007; Fax: 44-114-2560458; E-mail: j.w.haycock@shef.ac.uk.
Abbreviations:

MSH

melanocyte-stimulating hormone

MC

melanocortin

TNF-α

tumor necrosis factor-α

IL

interleukin

NF-κB

nuclear factor κB

ROS

reactive oxygen species

GPx

glutathione peroxidase

PBS

phosphate-buffered saline

IBMX

isobutylmethylxanthine

ACTH

adrenocorticotropic hormone

ICAM-1

intercellular adhesion molecule 1

DCFH-DA

2′,7′-dichlorofluorohydrazine diacetate
- Received January 27, 2000.
- Revision received March 2, 2000.
The American Society for Biochemistry and Molecular Biology, Inc.