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Bautista RM, Carter KM, Jarrett SG, Napier D, Wakamatsu K, Ito S, D'Orazio JA. Cutaneous pharmacologic cAMP induction induces melanization of the skin and improves recovery from ultraviolet injury in melanocortin 1 receptor-intact or heterozygous skin. Pigment Cell Melanoma Res 2019; 33:30-40. [PMID: 31398282 DOI: 10.1111/pcmr.12817] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 07/05/2019] [Accepted: 08/05/2019] [Indexed: 12/23/2022]
Abstract
Homozygous loss of function of the melanocortin 1 receptor (MC1R) is associated with a pheomelanotic pigment phenotype and increased melanoma risk. MC1R heterozygosity is less well studied, although individuals inheriting one loss-of-function MC1R allele are also melanoma-prone. Using the K14-Scf C57BL/6J animal model whose skin is characterized by lifelong retention of interfollicular epidermal melanocytes like that of the human, we studied pigmentary, UV responses, and DNA repair capacity in the skin of variant Mc1r background. Topical application of forskolin, a skin-permeable pharmacologic activator of cAMP induction to mimic native Mc1r signaling, increased epidermal eumelanin levels, increased the capacity of Mc1r-heterozygous skin to resist UV-mediated inflammation, and enhanced the skin's ability to clear UV photolesions from DNA. Interestingly, topical cAMP induction also promoted melanin accumulation, UV resistance, and accelerated clearance in Mc1r fully intact skin. Together, our findings suggest that heterozygous Mc1r loss is associated with an intermediately melanized and DNA repair-proficient epidermal phenotype and that topical cAMP induction enhances UV resistance in Mc1r-heterozygous or Mc1r-wild-type individuals by increasing eumelanin deposition and by improving nucleotide excision repair.
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Affiliation(s)
- Robert-Marlo Bautista
- The Markey Cancer Center, University of Kentucky, Lexington, KY, USA.,The Department of Surgery, University of Kentucky, Lexington, KY, USA
| | | | - Stuart Gordon Jarrett
- The Markey Cancer Center, University of Kentucky, Lexington, KY, USA.,The Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, KY, USA
| | - Dana Napier
- The Markey Cancer Center, University of Kentucky, Lexington, KY, USA
| | | | - Shosuke Ito
- The Fujita Health University, Nagoya, Aichi, Japan
| | - John August D'Orazio
- The Markey Cancer Center, University of Kentucky, Lexington, KY, USA.,The Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, KY, USA.,The Department of Pediatrics, University of Kentucky, Lexington, KY, USA
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Jarrett SG, Carter KM, D'Orazio JA. Paracrine regulation of melanocyte genomic stability: a focus on nucleotide excision repair. Pigment Cell Melanoma Res 2017; 30:284-293. [PMID: 28192636 DOI: 10.1111/pcmr.12582] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 02/08/2017] [Indexed: 02/06/2023]
Abstract
UV radiation is a major environmental risk factor for the development of melanoma by causing DNA damage and mutations. Resistance to UV damage is largely determined by the capacity of melanocytes to respond to UV injury by repairing mutagenic photolesions. The nucleotide excision repair (NER) pathway is the major mechanism by which cells correct UV photodamage. This multistep process involves the basic steps of damage recognition, isolation, localized strand unwinding, assembly of a repair complex, excision of the damage-containing strand 3' and 5' to the photolesion, synthesis of a sequence-appropriate replacement strand, and finally ligation to restore continuity of genomic DNA. In melanocytes, the efficiency of NER is regulated by several hormonal pathways including the melanocortin and endothelin signaling pathways. Elucidating molecular mechanisms by which melanocyte DNA repair is regulated offers the possibility of developing novel melanoma-preventive strategies to reduce UV mutagenesis, especially in UV-sensitive melanoma-prone individuals.
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Affiliation(s)
- Stuart Gordon Jarrett
- Markey Cancer Center, University of Kentucky College of Medicine, Lexington, KY, USA.,Department of Toxicology and Cancer Biology, University of Kentucky College of Medicine, Lexington, KY, USA
| | | | - John August D'Orazio
- Markey Cancer Center, University of Kentucky College of Medicine, Lexington, KY, USA.,Department of Toxicology and Cancer Biology, University of Kentucky College of Medicine, Lexington, KY, USA.,Department of Physiology, University of Kentucky College of Medicine, Lexington, KY, USA.,Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, USA.,Department of Pediatrics, University of Kentucky College of Medicine, Lexington, KY, USA
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Jarrett SG, Horrell EMW, Christian PA, Vanover JC, Boulanger MC, Zou Y, D'Orazio JA. Abstract A34: MC1R signaling reduces UV mutagenesis by ATR-mediated recruitment of XPA to photolesions. Cancer Res 2015. [DOI: 10.1158/1538-7445.mel2014-a34] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
The melanocortin 1 receptor (MC1R), which signals through cAMP, is a melanocytic Gs-coupled transmembrane receptor activated by binding to its high-affinity ligand, α-melanocyte stimulating hormone (MSH). Besides influencing pigment phenotype and mediating adaptive tanning, MC1R signaling is intricately linked with genome maintenance and DNA repair. Individuals harboring loss-of-function MC1R polymorphisms are UV sensitive and melanoma-prone. We have determined that MC1R-mediated cAMP signaling promotes nucleotide excision repair (NER) in a cAMP-dependent protein kinase A (PKA)-dependent manner. PKA directly phosphorylates ataxia telangiectasia and Rad3-related protein (ATR) at Ser435 which actively recruits the key NER protein xeroderma pigmentosum complementation group A (XPA) to sites of nuclear UV photodamage, accelerating clearance of UV-induced photolesions and reducing UV mutagenesis. Loss of Ser435 within ATR prevents PKA-mediated ATR phosphorylation, disrupts ATR-XPA binding, delays recruitment of XPA to UV-damaged DNA and elevates UV-induced mutagenesis. PKA-mediated ATR phosphorylation on Ser435 appears to induce a DNA repair-specific function of ATR independent of Chk1 phosphorylation and cell cycle arrest. Importantly, MC1R signaling defects and sub-optimal DNA repair are overcome by forskolin-mediated cAMP induction in melanocytes and in whole skin. Our findings mechanistically link cAMP-PKA signaling to NER and illustrate the potential benefits of cAMP pharmacological rescue to reduce UV mutagenesis in MC1R-defective, melanoma-susceptible individuals.
Citation Format: Stuart Gordon Jarrett, Erin M. Wolf Horrell, Perry A. Christian, Jillian C. Vanover, Mary C. Boulanger, Yue Zou, John August D'Orazio. MC1R signaling reduces UV mutagenesis by ATR-mediated recruitment of XPA to photolesions. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Melanoma: From Biology to Therapy; Sep 20-23, 2014; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(14 Suppl):Abstract nr A34.
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Affiliation(s)
| | | | | | | | | | - Yue Zou
- 2East Tennessee State University, Johnson City, TN
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