RESUMO
BACKGROUND: Understanding multiple components of risk perceptions is important because perceived risk predicts engagement in prevention behaviors. PURPOSE: To examine how multiple components of risk perceptions (perceived magnitude of and worry about risk, prioritization of the management of one's risk) changed following genetic counseling with or without test reporting, and to examine which of these components prospectively predicted improvements in sun-protection behavior 1 year later. METHODS: A prospective, nonrandomized study design was used. Participants were 114 unaffected members of melanoma-prone families who (i) underwent genetic testing for a CDKN2A/p16 mutation (n = 69) or (ii) were at comparably elevated risk based on family history and underwent genetic counseling but not testing (no-test controls, n = 45). Participants reported risk perception components and sun-protection behavior at baseline, immediately following counseling, and 1 month and 1 year after counseling. RESULTS: Factor analysis indicated three risk components. Carriers reported increased perceived magnitude and priority of risk, but not cancer worry. No-test controls showed no changes in any risk perception. Among noncarriers, priority of risk remained high at all assessments, whereas magnitude of risk and cancer worry decreased. Of the three risk components, greater priority of risk uniquely predicted improved self-reported sun protection 1 year post-counseling. CONCLUSIONS: Priority of risk (i) seems to be a component of risk perceptions distinguishable from magnitude of risk and cancer worry, (ii) may be an important predictor of daily prevention behavior, and (iii) remained elevated 1 year following genetic counseling only for participants who received a positive melanoma genetic test result.
Assuntos
Aconselhamento Genético/psicologia , Predisposição Genética para Doença/psicologia , Testes Genéticos , Melanoma/genética , Comportamento de Redução do Risco , Neoplasias Cutâneas/genética , Adolescente , Adulto , Idoso , Exposição Ambiental/efeitos adversos , Feminino , Genes p16 , Humanos , Masculino , Pessoa de Meia-Idade , Mutação/genética , Estudos Prospectivos , Luz Solar/efeitos adversos , Raios Ultravioleta/efeitos adversos , Melanoma Maligno CutâneoRESUMO
PURPOSE: This study investigated whether genetic counseling and test reporting for the highly penetrant CDKN2A melanoma predisposition gene promoted decreases in sun exposure. METHODS: A prospective, nonequivalent control group design compared unaffected participants (N = 128, Mage = 35.24, 52% men) from (1) families known to carry a CDKN2A pathogenic variant, who received counseling about management recommendations and a positive or negative genetic test result and (2) no-test control families known not to carry a CDKN2A pathogenic variant, who received equivalent counseling based on their comparable family history. Changes in daily ultraviolet radiation (UVR) exposure (J/m2), skin pigmentation (melanin index), and sunburns between baseline and one year following counseling were compared among carriers (n = 32), noncarriers (n = 46), and no-test control participants (n = 50). RESULTS: Both carriers and no-test control participants exhibited a decrease one year later in daily UVR dose (B = -0.52, -0.33, p < 0.01). Only carriers exhibited a significant decrease in skin pigmentation at the wrist one year later (B = -0.11, p < 0.001), and both carriers and no-test control participants reported fewer sunburns than noncarriers (p < 0.05). Facial pigmentation did not change for any group. Noncarriers did not change on any measure of UVR exposure. CONCLUSIONS: These findings support the clinical utility of disclosing CDKN2A test results and providing risk management education to high-risk individuals.
Assuntos
Inibidor p16 de Quinase Dependente de Ciclina/genética , Aconselhamento Genético/métodos , Testes Genéticos/métodos , Melaninas/metabolismo , Queimadura Solar/epidemiologia , Adolescente , Adulto , Idoso , Estudos de Casos e Controles , Feminino , Heterozigoto , Humanos , Masculino , Pessoa de Meia-Idade , Mutação , Linhagem , Estudos Prospectivos , Exposição à Radiação/estatística & dados numéricos , Queimadura Solar/metabolismo , Luz Solar/efeitos adversos , Adulto JovemRESUMO
We report the first diselenide-based probe for the selective detection of thioredoxin reductase (TrxR), an enzyme commonly overexpressed in melanomas. The probe design involves conjugation of a seminaphthorhodafluor dye with a diselenide moiety. TrxR reduces the diselenide bond, triggering a fluorescence turn-on response of the probe. Kinetic studies reveal favorable binding of the probe with TrxR with a Michaelis-Menten constant (Km ) of 15.89â µm. Computational docking simulations predict a greater binding affinity to the TrxR active site in comparison to its disulfide analogue. Inâ vitro imaging studies further confirmed the diselenide probe exhibited improved signaling of TrxR activity compared to the disulfide analogue.
Assuntos
Corantes Fluorescentes/uso terapêutico , Tiorredoxina Dissulfeto Redutase/metabolismo , HumanosRESUMO
Recent progress in the treatment of advanced melanoma has led to unprecedented improvements in overall survival and, as these new melanoma treatments have been developed and deployed in the clinic, much has been learned about the natural history of the disease. Now is the time to apply that knowledge toward the design and clinical evaluation of new chemoprevention agents. Melanoma chemoprevention has the potential to reduce dramatically both the morbidity and the high costs associated with treating patients who have metastatic disease. In this work, scientific and clinical melanoma experts from the national Melanoma Prevention Working Group, composed of National Cancer Trials Network investigators, discuss research aimed at discovering and developing (or repurposing) drugs and natural products for the prevention of melanoma and propose an updated pipeline for translating the most promising agents into the clinic. The mechanism of action, preclinical data, epidemiological evidence, and results from available clinical trials are discussed for each class of compounds. Selected keratinocyte carcinoma chemoprevention studies also are considered, and a rationale for their inclusion is presented. These data are summarized in a table that lists the type and level of evidence available for each class of agents. Also included in the discussion is an assessment of additional research necessary and the likelihood that a given compound may be a suitable candidate for a phase 3 clinical trial within the next 5 years.
Assuntos
Melanoma/prevenção & controle , Protetores contra Radiação/uso terapêutico , Neoplasias Cutâneas/prevenção & controle , Animais , Anticarcinógenos/uso terapêutico , Quimioprevenção , Ensaios Clínicos Fase III como Assunto , Desenvolvimento de Medicamentos , Reposicionamento de Medicamentos , Feminino , Humanos , Masculino , Neoplasias Cutâneas/tratamento farmacológicoRESUMO
Treatment with vemurafenib, a potent and selective inhibitor of mitogen-activated protein kinase signaling downstream of the BRAFV600E oncogene, elicits dramatic clinical responses in patients with metastatic melanoma. Unfortunately, the clinical utility of this drug is limited by a high incidence of drug resistance. Thus, there is an unmet need for alternative therapeutic strategies to treat vemurafenib-resistant metastatic melanomas. We have conducted high-throughput screening of two bioactive compound libraries (Siga and Spectrum libraries) against a metastatic melanoma cell line (A2058) and identified two structurally analogous compounds, deguelin and rotenone, from a cell viability assay. Vemurafenib-resistant melanoma cell lines, A2058R and A375R (containing the BRAFV600E mutation), also showed reduced proliferation when treated with these two compounds. Deguelin, a mitochondrial complex I inhibitor, was noted to significantly inhibit oxygen consumption in cellular metabolism assays. Mechanistically, deguelin treatment rapidly activates AMPK signaling, which results in inhibition of mTORC1 signaling and differential phosphorylation of mTORC1's downstream effectors, 4E-BP1 and p70S6 kinase. Deguelin also significantly inhibited ERK activation and Ki67 expression without altering Akt activation in the same timeframe in the vemurafenib-resistant melanoma cells. These data posit that treatment with metabolic regulators, such as deguelin, can lead to energy starvation, thereby modulating the intracellular metabolic environment and reducing survival of drug-resistant melanomas harboring BRAF V600E mutations.
Assuntos
Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Complexo I de Transporte de Elétrons/antagonistas & inibidores , Melanoma/tratamento farmacológico , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas B-raf/genética , Rotenona/análogos & derivados , Vemurafenib/farmacologia , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/genética , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Melanoma/genética , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Mutação/efeitos dos fármacos , Rotenona/farmacologia , Transdução de Sinais/efeitos dos fármacosRESUMO
Several distinct melanoma syndromes have been defined, and genetic tests are available for the associated causative genes. Guidelines for melanoma genetic testing have been published as an informal "rule of twos and threes," but these guidelines apply to CDKN2A testing and are not intended for the more recently described non-CDKN2A melanoma syndromes. In order to develop an approach for the full spectrum of hereditary melanoma patients, we have separated melanoma syndromes into two types: "melanoma dominant" and "melanoma subordinate." Syndromes in which melanoma is a predominant cancer type are considered melanoma dominant, although other cancers, such as mesothelioma or pancreatic cancers, may also be observed. These syndromes are associated with defects in CDKN2A, CDK4, BAP1, MITF, and POT1. Melanoma-subordinate syndromes have an increased but lower risk of melanoma than that of other cancer(s) seen in the syndrome, such as breast and ovarian cancer or Cowden syndrome. Many of these melanoma-subordinate syndromes are associated with well-established predisposition genes (e.g., BRCA1/2, PTEN). It is likely that these predisposition genes are responsible for the increased susceptibility to melanoma as well but with lower penetrance than that observed for the dominant cancer(s) in those syndromes. In this review, we describe our extension of the "rule of twos and threes" for melanoma genetic testing. This algorithm incorporates an understanding of the spectrum of cancers and genes seen in association with melanoma to create a more comprehensive and tailored approach to genetic testing.
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Melanoma/genética , Melanoma/terapia , Algoritmos , Predisposição Genética para Doença , Testes Genéticos , Humanos , Melanoma/diagnósticoRESUMO
Genetic testing of minors is advised only for conditions in which benefits of early intervention outweigh potential psychological harms. This study investigated whether genetic counseling and test reporting for the CDKN2A/p16 mutation, which confers highly elevated melanoma risk, improved sun protection without inducing distress. Eighteen minors (Mage = 12.4, SD = 1.9) from melanoma-prone families completed measures of protective behavior and distress at baseline, 1 week (distress only), 1 month, and 1 year following test disclosure. Participants and their mothers were individually interviewed on the psychological and behavioral impact of genetic testing 1 month and 1 year post-disclosure. Carriers (n = 9) and noncarriers (n = 9) reported significantly fewer sunburns and a greater proportion reported sun protection adherence between baseline and 1 year post-disclosure; results did not vary by mutation status. Anxiety symptoms remained low post-disclosure, while depressive symptoms and cancer worry decreased. Child and parent interviews corroborated these findings. Mothers indicated that genetic testing was beneficial (100%) because it promoted risk awareness (90.9%) and sun protection (81.8%) without making their children scared (89.9%); several noted their child's greater independent practice of sun protection (45.4%). In this small initial study, minors undergoing CDKN2A/p16 genetic testing reported behavioral improvements and consistently low distress, suggesting such testing may be safely implemented early in life, allowing greater opportunity for risk-reducing lifestyle changes.
Assuntos
Testes Genéticos , Melanoma/diagnóstico , Melanoma/genética , Neoplasias Cutâneas/diagnóstico , Neoplasias Cutâneas/genética , Adolescente , Adulto , Criança , Feminino , Aconselhamento Genético/psicologia , Predisposição Genética para Doença , Humanos , Masculino , Menores de Idade , Comportamento de Redução do RiscoRESUMO
Efforts to prevent melanoma, especially for those at elevated risk for the disease, should ideally begin during childhood. However, there are few preventive interventions targeting children who are at higher risk for melanoma due to a family history of the disease. Further, there are no educational interventions that aim to help these at-risk children understand their risk for melanoma and the ways in which preventive behaviors, such as sun protection, can mitigate their risk. The current paper describes a multidisciplinary team's process for creating a developmentally appropriate educational intervention about melanoma risk and prevention for children ages 8-17 years who have a family history of melanoma. Drawing from the fields of dermatology, health behavior change and education, genetic risk communication, science education, and graphic arts, the multimedia intervention created covers key learning points relevant to understanding melanoma, the role of DNA damage in melanoma development, inherited risk factors for melanoma, environmental factors causing DNA damage, and methods for preventing DNA damage, such as sun protective behaviors. Lessons learned during the development of the educational intervention, particularly relevant to multidisciplinary team interactions, are discussed. Implications for future testing and refinement of the novel educational content are also reviewed.
Assuntos
Predisposição Genética para Doença , Melanoma , Educação de Pacientes como Assunto , Neoplasias Cutâneas , Adolescente , Criança , Feminino , Comportamentos Relacionados com a Saúde , Humanos , Masculino , Melanoma/genética , Melanoma/prevenção & controle , Fatores de Risco , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/prevenção & controleRESUMO
Detection and removal of melanoma, before it has metastasized, dramatically improves prognosis and survival. The purpose of this chapter is to (1) summarize current methods of melanoma detection and (2) review state-of-the-art detection methods and technologies that have the potential to reduce melanoma mortality. Current strategies for the detection of melanoma range from population-based educational campaigns and screening to the use of algorithm-driven imaging technologies and performance of assays that identify markers of transformation. This chapter will begin by describing state-of-the-art methods for educating and increasing awareness of at-risk individuals and for performing comprehensive screening examinations. Standard and advanced photographic methods designed to improve reliability and reproducibility of the clinical examination will also be reviewed. Devices that magnify and/or enhance malignant features of individual melanocytic lesions (and algorithms that are available to interpret the results obtained from these devices) will be compared and contrasted. In vivo confocal microscopy and other cellular-level in vivo technologies will be compared to traditional tissue biopsy, and the role of a noninvasive "optical biopsy" in the clinical setting will be discussed. Finally, cellular and molecular methods that have been applied to the diagnosis of melanoma, such as comparative genomic hybridization (CGH), fluorescent in situ hybridization (FISH), and quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), will be discussed.
Assuntos
Melanoma/diagnóstico , Hibridização Genômica Comparativa , Dermoscopia , Detecção Precoce de Câncer , Humanos , Hibridização in Situ Fluorescente , Microscopia Confocal , Educação de Pacientes como Assunto , AutoexameRESUMO
Beginning in the last decade of the twentieth century, the fields of pigment cell research and melanoma have witnessed major breakthroughs in the understanding of the role of melanocortins in human pigmentation and the DNA damage response of human melanocytes to solar ultraviolet radiation (UV). This began with the cloning of the melanocortin 1 receptor (MC1R) gene from human melanocytes and the demonstration that the encoded receptor is functional. Subsequently, population studies found that the MC1R gene is highly polymorphic, and that some of its variants are associated with red hair phenotype, fair skin and poor tanning ability. Using human melanocytes cultured from donors with different MC1R genotypes revealed that the alleles associated with red hair color encode for a non-functional receptor. Epidemiological studies linked the MC1R red hair color variants to increased melanoma risk. Investigating the impact of different MC1R variants on the response of human melanocytes to UV led to the important discovery that the MC1R signaling activates antioxidant, DNA repair and survival pathways, in addition to stimulation of eumelanin synthesis. These effects of MC1R were absent in melanocytes expressing 2 MC1R red hair color variants that result in loss of function of the receptor. The importance of the MC1R in reducing UV-induced genotoxicity in melanocytes led us to design small peptide analogs of the physiological MC1R agonist α-melanocortin (α-melanocyte stimulating hormone; α-MSH) for the goal of utilizing them for melanoma chemoprevention.
Assuntos
Melanocortinas/metabolismo , Melanoma/metabolismo , Receptor Tipo 1 de Melanocortina/metabolismo , Dano ao DNA , Regulação da Expressão Gênica , Humanos , Melaninas/biossíntese , Melanócitos/metabolismo , Melanócitos/efeitos da radiação , Melanoma/etiologia , Melanoma/prevenção & controle , Pigmentação/genética , Pigmentação/fisiologia , Polimorfismo Genético , Receptor Tipo 1 de Melanocortina/genética , Transdução de Sinais , Pesquisa Translacional Biomédica , Raios Ultravioleta/efeitos adversosRESUMO
The incidence of cutaneous melanoma has risen at a rate significantly higher than that for other malignancies. This increase persists despite efforts to educate the public about the dangers of excess exposure to UV radiation from both the sun and tanning beds. Melanoma affects a relatively younger population and is notorious for its propensity to metastasize and for its poor response to current therapeutic regimens. These factors make prevention an integral component to the goal of decreasing melanoma-related mortality. Transformation of melanocytes into malignant melanoma involves the interplay between genetic factors, UV exposure, and the tumor microenvironment. The roles of UV radiation in the etiology of melanoma are mediated by both direct damage of DNA through formation of photoproducts and production of reactive oxygen species (ROS). Many of the promising antioxidant agents under development for the prevention of melanoma are derived from foodstuffs. B-Raf is a member of the Raf kinase family of serine/threonine-specific protein kinases that plays a role in regulating the MAP kinase/ERKs signaling pathway. About 50 % of melanomas harbor activating BRAF mutations. BRAF mutations are found in 59 % of the melanomas arising in skin with intermittent sun exposure, such as trunk and arms, as compared with only 23 % of the acral melanomas, 11 % of mucosal melanomas, and 0 % of uveal melanomas. Two new agents, ipilimumab and vemurafenib, have been shown to improve outcome of advanced melanoma as presented at the plenary session of the 2011 annual meeting of the American Society of Clinical Oncology. Vemurafenib is the first personalized compound which demonstrated an improvement in progression-free survival (PFS) and overall survival (OS) in metastatic melanoma harboring the BRAFV600 mutation and represents the first drug of a class that exerts its anti-proliferative activity through inhibition of a highly specific molecular target. GSK2118436 (dabrafenib), the second BRAF inhibitor, in phase I and II trial obtained similar results to vemurafenib. A phase III trial is now ongoing. Taken together, the early clinical development of vemurafenib and dabrafenib clearly confirms that BRAF inhibitors can halt or reverse disease in patients with melanomas carrying this mutation, improving survival times compared with historically standard treatments (chemotherapy and interleukin-2). The clinical development of other new BRAF inhibitors such as RAF265 and LGX818 is now ongoing. Combination strategies of BRAF inhibitors with ipilimumab, an anti-CTLA-4 antibody, and/or MEK inhibitors or metformin are now under investigation in clinical trials.
Assuntos
Antineoplásicos/uso terapêutico , Melanoma/prevenção & controle , Terapia de Alvo Molecular , Animais , Humanos , Melanoma/metabolismoRESUMO
Importance: There is no US Food and Drug Administration-approved treatment for pityriasis rubra pilaris (PRP), and it is common for patients to fail to experience improvement with several systemic options. Involvement of interleukin (IL) 23 suggests a potential therapeutic target. Objective: To determine whether guselkumab, an IL-23p19 inhibitor, provides clinical improvement for participants with PRP and better understand gene and protein dysregulation in PRP. Design, Setting, and Participants: This single-arm, investigator-initiated nonrandomized trial was conducted from October 2019 to August 2022 at a single-center academic university with participants from 8 states in the US. In total, 14 adults with moderate to severe PRP were enrolled; 12 completed the trial. Age-matched and sex-matched healthy controls provided skin and blood for proteomic and transcriptomic studies. The primary outcome was observed at 24 weeks, and additional follow-up occurred at 36 weeks. Intervention: Guselkumab is a fully human immunoglobulin G1 λ monoclonal antibody that selectively binds and inhibits the p19 subunit of IL-23. Subcutaneous injections were given at the US Food and Drug Administration-approved dosing schedule for psoriasis over a 24-week period. Main Outcomes and Measures: The primary outcome was the mean change in the Psoriasis Area Severity Index (PASI) score at week 24. Secondary outcomes included pruritus, Dermatology Life Quality Index score, clinical response at week 36, and association with transcriptomics and proteomics expression. Results: A per-protocol analysis was performed for the cohort of 4 female and 8 male patients who had a mean (SD) age of 56.5 (18.7) years. The mean improvement in PASI score, pruritus, and Dermatology Life Quality Index score was 61.8% (P < .001), 62.3% (P = .001), and 60.2% (P < .001), respectively. Nine participants (75%) achieved a 50% improvement in PASI. Among these clinical responders, at week 36, 8 of 9 achieved PASI75, and 6 of 9 achieved PASI90. No participants had pathogenic CARD14 gene variations. There was 1 serious adverse event that was not associated with the study drug. Proteomics and gene expression profiles identified dysregulation of a predominance of inflammatory pathways (such as T helper 17 and nuclear factor κ B) in participants with PRP who later responded well to treatment with guselkumab and stronger dysregulation of keratinocyte development pathways in individuals who did not respond to guselkumab. Conclusion and Relevance: The results of this nonrandomized trial suggest that guselkumab has efficacy in treating refractory moderate to severe adult PRP. Trial Registration: ClinicalTrials.gov Identifier: NCT03975153.
Assuntos
Anticorpos Monoclonais Humanizados , Interleucina-17 , Pitiríase Rubra Pilar , Transdução de Sinais , Humanos , Pitiríase Rubra Pilar/tratamento farmacológico , Masculino , Feminino , Anticorpos Monoclonais Humanizados/administração & dosagem , Anticorpos Monoclonais Humanizados/farmacologia , Pessoa de Meia-Idade , Adulto , Interleucina-17/antagonistas & inibidores , Interleucina-17/metabolismo , Transdução de Sinais/efeitos dos fármacos , Índice de Gravidade de Doença , Interleucina-23/antagonistas & inibidores , Resultado do Tratamento , Subunidade p19 da Interleucina-23/antagonistas & inibidores , Idoso , Injeções Subcutâneas , Guanilato Ciclase/metabolismo , Proteínas de Membrana , Proteínas Adaptadoras de Sinalização CARDRESUMO
Pigment-producing melanocytes overcome frequent oxidative stress in their physiological role of protecting the skin against the deleterious effects of solar UV irradiation. This is accomplished by the activity of several endogenous antioxidant systems, including the thioredoxin antioxidant system, in which thioredoxin reductase 1 (TR1) plays an important part. To determine whether TR1 contributes to the redox regulation of melanocyte homeostasis, we have generated a selective melanocytic Txnrd1-knockout mouse model (Txnrd1melâ/â), which exhibits a depigmentation phenotype consisting of variable amelanotic ventral spotting and reduced pigmentation on the extremities (tail tip, ears, and paws). The antioxidant role of TR1 was further probed in the presence of acute neonatal UVB irradiation, which stimulates melanocyte activation and introduces a spike in oxidative stress in the skin microenvironment. Interestingly, we observed a significant reduction in overall melanocyte count and proliferation in the absence of TR1. Furthermore, melanocytes exhibited an elevated level of UV-induced DNA damage in the form of 8-oxo-2'-deoxyguanosine after acute UVB treatment. We also saw an engagement of compensatory antioxidant mechanisms through increased nuclear localization of transcription factor NRF2. Altogether, these data indicate that melanocytic TR1 positively regulates melanocyte homeostasis and pigmentation during development and protects against UVB-induced DNA damage and oxidative stress.
Assuntos
Fotobiologia , Tiorredoxina Redutase 1 , Animais , Antioxidantes/farmacologia , Melanócitos/efeitos da radiação , Camundongos , Pigmentação , Tiorredoxina Redutase 1/genética , Raios UltravioletaRESUMO
TR1 and other selenoproteins have paradoxical effects in melanocytes and melanomas. Increasing selenoprotein activity with supplemental selenium in a mouse model of UV-induced melanoma prevents oxidative damage to melanocytes and delays melanoma tumor formation. However, TR1 itself is positively associated with progression in human melanomas and facilitates metastasis in melanoma xenografts. Here, we report that melanocytes expressing a microRNA directed against TR1 (TR1low) grow more slowly than control cell lines and contain significantly less melanin. This phenotype is associated with lower tyrosinase (TYR) activity and reduced transcription of tyrosinase-like protein-1 (TYRP1). Melanoma cells in which the TR1 gene (TXNRD1) was disrupted using Crispr/Cas9 showed more dramatic effects including the complete loss of the melanocyte-specific isoform of MITF; other MITF isoforms were unaffected. We provide evidence that TR1 depletion results in oxidation of MITF itself. This newly discovered mechanism for redox modification of MITF has profound implications for controlling both pigmentation and tumorigenesis in cells of the melanocyte lineage.
RESUMO
Ultraviolet radiation (UVR) exposure is the most important modifiable risk factor for skin cancer development. Although sunscreen and sun-protective clothing are essential tools to minimize UVR exposure, few studies have compared the two modalities head-to-head. This study evaluates the UV-protective capacity of four modern, sun-protective textiles and two broad-spectrum, organic sunscreens (SPF 30 and 50). Sun Protection Factor (SPF), Ultraviolet Protection Factor (UPF), Critical Wavelength (CW), and % UVA- and % UVB-blocking were measured for each fabric. UPF, CW, % UVA- and % UVB-blocking were measured for each sunscreen at 2 mg/cm2 (recommended areal density) and 1 mg/cm2 (simulating real-world consumer application). The four textiles provided superior UVR protection when compared to the two sunscreens tested. All fabrics blocked erythemogenic UVR better than the sunscreens, as measured by SPF, UPF, and % UVB-blocking. Each fabric was superior to the sunscreens in blocking full-spectrum UVR, as measured by CW and % UVA-blocking. Our data demonstrate the limitations of sunscreen and UV-protective clothing labeling and suggest the combination of SPF or UPF with % UVA-blocking may provide more suitable measures for broad-spectrum protection. While sunscreen remains an important photoprotective modality (especially for sites where clothing is impractical), these data suggest that clothing should be considered the cornerstone of UV protection.
RESUMO
A role for dopamine (DA) in the regulation of clock genes in the mammalian brain is suggested by evidence that manipulations of DA receptors can alter the expression of some clock genes outside the suprachiasmatic nucleus (SCN), the master circadian clock. The role of endogenous DA in the regulation of clock gene expression is unknown. Here, we demonstrate a direct relationship between extracellular DA levels and the rhythm of expression of the clock protein PERIOD2 (PER2) in the dorsal striatum of the male Wistar rat. Specifically, we show that the peak of the daily rhythm of extracellular DA in the dorsal striatum precedes the peak of PER2 by â¼6 h and that depletion of striatal DA by 6-hydroxydopamine or α-methyl-para-tyrosine or blockade of D(2) DA receptors by raclopride blunts the rhythm of striatal PER2. Furthermore, timed daily activation of D(2) DA receptors, but not D(1) DA receptors, restores and entrains the PER2 rhythm in the DA-depleted striatum. None of these manipulations had any effect on the PER2 rhythm in the SCN. Our findings are consistent with the idea that the rhythm of expression of PER2 in the dorsal striatum depends on daily dopaminergic activation of D(2) DA receptors. These observations may have implications for circadian abnormalities seen in Parkinson's disease.
Assuntos
Corpo Estriado/fisiologia , Dopamina/fisiologia , Proteínas Circadianas Period/biossíntese , Proteínas Circadianas Period/genética , Receptores de Dopamina D2/fisiologia , Animais , Contagem de Células , Cromatografia Líquida de Alta Pressão , Corpo Estriado/citologia , Dopamina/metabolismo , Antagonistas dos Receptores de Dopamina D2 , Regulação da Expressão Gênica/fisiologia , Imuno-Histoquímica , Masculino , Feixe Prosencefálico Mediano/fisiologia , Microdiálise , Atividade Motora/fisiologia , Oxidopamina , RNA/biossíntese , RNA/genética , Ratos , Ratos Wistar , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Núcleo Supraquiasmático/citologia , Núcleo Supraquiasmático/metabolismo , Simpatectomia Química , Simpatolíticos , Tirosina 3-Mono-Oxigenase/antagonistas & inibidoresRESUMO
The melanocortin 1 receptor gene is a main determinant of human pigmentation, and a melanoma susceptibility gene, because its variants that are strongly associated with red hair color increase melanoma risk. To test experimentally the association between melanocortin 1 receptor genotype and melanoma susceptibility, we compared the responses of primary human melanocyte cultures naturally expressing different melanocortin 1 receptor variants to α-melanocortin and ultraviolet radiation. We found that expression of 2 red hair variants abolished the response to α-melanocortin and its photoprotective effects, evidenced by lack of functional coupling of the receptor, and absence of reduction in ultraviolet radiation-induced hydrogen peroxide generation or enhancement of repair of DNA photoproducts, respectively. These variants had different heterozygous effects on receptor function. Microarray data confirmed the observed differences in responses of melanocytes with functional vs. nonfunctional receptor to α-melanocortin and ultraviolet radiation, and identified DNA repair and antioxidant genes that are modulated by α-melanocortin. Our findings highlight the molecular mechanisms by which the melanocortin 1 receptor genotype controls genomic stability of and the mutagenic effect of ultraviolet radiation on human melanocytes.
Assuntos
Melanócitos/efeitos da radiação , Receptor Tipo 1 de Melanocortina/genética , Raios Ultravioleta , Células Cultivadas , Genótipo , HumanosRESUMO
Five years ago, the Melanoma Research Foundation (MRF) conducted an assessment of the challenges and opportunities facing the melanoma research community and patients with melanoma. Since then, remarkable progress has been made on both the basic and clinical research fronts. However, the incidence, recurrence, and death rates for melanoma remain unacceptably high and significant challenges remain. Hence, the MRF Scientific Advisory Council and Breakthrough Consortium, a group that includes clinicians and scientists, reconvened to facilitate intensive discussions on thematic areas essential to melanoma researchers and patients alike, prevention, detection, diagnosis, metastatic dormancy and progression, response and resistance to targeted and immune-based therapy, and the clinical consequences of COVID-19 for patients with melanoma and providers. These extensive discussions helped to crystalize our understanding of the challenges and opportunities facing the broader melanoma community today. In this report, we discuss the progress made since the last MRF assessment, comment on what remains to be overcome, and offer recommendations for the best path forward.
Assuntos
COVID-19/prevenção & controle , Oncologia/métodos , Melanoma/terapia , Guias de Prática Clínica como Assunto , SARS-CoV-2/isolamento & purificação , Neoplasias Cutâneas/terapia , Pesquisa Biomédica/métodos , Pesquisa Biomédica/tendências , COVID-19/epidemiologia , COVID-19/virologia , Humanos , Oncologia/organização & administração , Oncologia/tendências , Melanoma/diagnóstico , SARS-CoV-2/fisiologia , Neoplasias Cutâneas/diagnósticoRESUMO
Predispositional genetic testing of children for adult-onset health risks is typically only used when prevention and screening measures have utility during childhood. Little is known about how children and their parents may use predispositional risk information, including whether it changes their interactions around risk-reducing prevention and screening behaviors. The current study examined perspectives on family interactions around skin cancer prevention and control practices through 1 year after test reporting and counseling among children who received melanoma predispositional genetic testing and their parents. Eighteen children (50% carriers, 56% male, mean age = 12.4 years) and 11 parents from 11 families participated in semi-structured interviews 1 month and 1 year after receiving the child's test result. Both parents (73%) and children (50%) reported making changes to family skin cancer prevention and control practices after receiving the test result. Parent- and child-reported discussions about melanoma prevention increased over time (36% parents and 61% children at 1 month, 73% parents and 67% at 1 year). One-quarter (27%) of parents and no children reported having conflicts about sun protection or screening 1 year after test reporting. A majority of parents (63%) reported treating their child differently at the 1-year follow-up, especially among carriers. Predispositional genetic testing for melanoma was associated with reported changes to plans for and discussions about sun protection, and high levels of parent-child collaboration to implement child sun protection. Future work could seek to identify child and parent factors and interactions that predict improved prevention and screening behaviors following pediatric predispositional genetic testing.
RESUMO
Importance: Pityriasis rubra pilaris is a rare and disabling cutaneous disease that is frequently recalcitrant to conventional therapies and appears to involve interleukin (IL)-17 overexpression. Objective: To investigate the clinical response and safety of ixekizumab in treating pityriasis rubra pilaris. Design, Setting, and Participants: Single-arm, investigator-initiated trial conducted in adult patients with moderate to severe pityriasis rubra pilaris at a single-center academic university from June 2018 to January 2020. A total of 41 patients were screened, 12 were enrolled, and 11 completed the full duration of therapy. A referred, consecutive sample was used during participant selection. The treatment period and primary outcome occurred over 24 weeks with additional patient follow-up through 36 weeks. Intervention: Subcutaneous administration of ixekizumab, a humanized IgG4 antibody that binds IL-17A, at the US Food and Drug Administration-approved dosing schedule for treatment of psoriasis for 24 weeks. Main Outcomes and Measures: The primary outcome was the mean change in Psoriasis Area and Severity Index at 24 weeks. Secondary outcomes included change in affected body surface area, quality of life, induction of sustained remission, and association of improvement with CARD14 genetic variations and cutaneous cytokine expression. Results: A total of 12 white patients (mean [SD] age, 49.8 [15.1] years; 8 male [67%]) were enrolled between June 2018 and April 2019, with 11 completing the full course of intervention. The mean (SEM) improvements in Psoriasis Area and Severity Index, affected body surface area, and Dermatology Life Quality Index were 15.2 (2.1) (P < .0001), 29.8% (9.3%) (P = .009), and 9.5 (2.5) (P = .004), respectively. The 4 participants with the most improvement in Psoriasis Area and Severity Index at week 24 stayed in remission at week 36 (defined as lack of increase in Psoriasis Area and Severity Index from week 24 through week 36), off therapy. Relative dermal IL-17A expression decreased by a 1.9 log-fold change. No participants had known pathogenic CARD14 variations. There were no serious adverse events. Conclusions and Relevance: In this single-armed trial, ixekizumab was associated with reduced clinical signs and symptoms of pityriasis rubra pilaris in a subset of patients, including those in whom other systemic therapies have failed. Trial Registration: ClinicalTrials.gov Identifier: NCT03485976.