Publication Date:
2012-11-06
Description:
People with pale skin, red hair, freckles and an inability to tan--the 'red hair/fair skin' phenotype--are at highest risk of developing melanoma, compared to all other pigmentation types. Genetically, this phenotype is frequently the product of inactivating polymorphisms in the melanocortin 1 receptor (MC1R) gene. MC1R encodes a cyclic AMP-stimulating G-protein-coupled receptor that controls pigment production. Minimal receptor activity, as in red hair/fair skin polymorphisms, produces the red/yellow pheomelanin pigment, whereas increasing MC1R activity stimulates the production of black/brown eumelanin. Pheomelanin has weak shielding capacity against ultraviolet radiation relative to eumelanin, and has been shown to amplify ultraviolet-A-induced reactive oxygen species. Several observations, however, complicate the assumption that melanoma risk is completely ultraviolet-radiation-dependent. For example, unlike non-melanoma skin cancers, melanoma is not restricted to sun-exposed skin and ultraviolet radiation signature mutations are infrequently oncogenic drivers. Although linkage of melanoma risk to ultraviolet radiation exposure is beyond doubt, ultraviolet-radiation-independent events are likely to have a significant role. Here we introduce a conditional, melanocyte-targeted allele of the most common melanoma oncoprotein, BRAF(V600E), into mice carrying an inactivating mutation in the Mc1r gene (these mice have a phenotype analogous to red hair/fair skin humans). We observed a high incidence of invasive melanomas without providing additional gene aberrations or ultraviolet radiation exposure. To investigate the mechanism of ultraviolet-radiation-independent carcinogenesis, we introduced an albino allele, which ablates all pigment production on the Mc1r(e/e) background. Selective absence of pheomelanin synthesis was protective against melanoma development. In addition, normal Mc1r(e/e) mouse skin was found to have significantly greater oxidative DNA and lipid damage than albino-Mc1r(e/e) mouse skin. These data suggest that the pheomelanin pigment pathway produces ultraviolet-radiation-independent carcinogenic contributions to melanomagenesis by a mechanism of oxidative damage. Although protection from ultraviolet radiation remains important, additional strategies may be required for optimal melanoma prevention.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3521494/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉 〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3521494/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Mitra, Devarati -- Luo, Xi -- Morgan, Ann -- Wang, Jin -- Hoang, Mai P -- Lo, Jennifer -- Guerrero, Candace R -- Lennerz, Jochen K -- Mihm, Martin C -- Wargo, Jennifer A -- Robinson, Kathleen C -- Devi, Suprabha P -- Vanover, Jillian C -- D'Orazio, John A -- McMahon, Martin -- Bosenberg, Marcus W -- Haigis, Kevin M -- Haber, Daniel A -- Wang, Yinsheng -- Fisher, David E -- 5R01 AR043369-16/AR/NIAMS NIH HHS/ -- F30 ES020663-01/ES/NIEHS NIH HHS/ -- R01 AR043369/AR/NIAMS NIH HHS/ -- R01 CA101864/CA/NCI NIH HHS/ -- R01 CA129933/CA/NCI NIH HHS/ -- R01 CA131075/CA/NCI NIH HHS/ -- R01 CA176839/CA/NCI NIH HHS/ -- R01-CA101864/CA/NCI NIH HHS/ -- T32 GM007753/GM/NIGMS NIH HHS/ -- England -- Nature. 2012 Nov 15;491(7424):449-53. doi: 10.1038/nature11624. Epub 2012 Oct 31.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Cutaneous Biology Research Center, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23123854" target="_blank"〉PubMed〈/a〉
Keywords:
Animals
;
Cell Line, Tumor
;
Cell Proliferation/drug effects
;
Gene Expression Regulation/drug effects
;
Hair Color/*genetics
;
Indoles/pharmacology
;
Melanins/metabolism
;
Melanoma/*genetics
;
Mice
;
Mice, Inbred C57BL
;
Monophenol Monooxygenase/genetics
;
Peroxidases/metabolism
;
Protein Kinase Inhibitors/pharmacology
;
Proto-Oncogene Proteins B-raf/genetics
;
Receptor, Melanocortin, Type 1/genetics
;
Skin Pigmentation/*genetics
;
Sulfonamides/pharmacology
;
Survival Analysis
;
Tumor Cells, Cultured
;
*Ultraviolet Rays
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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