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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
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
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.
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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
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.
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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
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
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.
Assuntos
Anticorpos Monoclonais Humanizados/administração & dosagem , Fármacos Dermatológicos/administração & dosagem , Pitiríase Rubra Pilar/tratamento farmacológico , Adulto , Anticorpos Monoclonais Humanizados/efeitos adversos , Proteínas Adaptadoras de Sinalização CARD/genética , Análise Mutacional de DNA , Fármacos Dermatológicos/efeitos adversos , Feminino , Seguimentos , Mutação com Ganho de Função , Guanilato Ciclase/genética , Humanos , Interleucina-17/análise , Interleucina-17/antagonistas & inibidores , Interleucina-17/metabolismo , Masculino , Proteínas de Membrana/genética , Pessoa de Meia-Idade , Pitiríase Rubra Pilar/diagnóstico , Pitiríase Rubra Pilar/genética , Pitiríase Rubra Pilar/patologia , Qualidade de Vida , Índice de Gravidade de Doença , Pele/efeitos dos fármacos , Pele/metabolismo , Pele/patologia , Resultado do TratamentoRESUMO
Broccoli sprout extract containing sulforaphane (BSE-SFN) has been shown to inhibit ultraviolet radiation-induced damage and tumor progression in skin. This study evaluated the toxicity and potential effects of oral BSE-SFN at three dosages. Seventeen patients who each had at least 2 atypical nevi and a prior history of melanoma were randomly allocated to 50, 100, or 200 µmol oral BSE-SFN daily for 28 days. Atypical nevi were photographed on days 1 and 28, and plasma and nevus samples were taken on days 1, 2, and 28. Endpoints assessed were safety, plasma and skin sulforaphane levels, gross and histologic changes, IHC for phospho-STAT3(Y705), Ki-67, Bcl-2, HMOX1, and TUNEL, plasma cytokine levels, and tissue proteomics. All 17 patients completed 28 days with no dose-limiting toxicities. Plasma sulforaphane levels pooled for days 1, 2, and 28 showed median postadministration increases of 120 ng/mL for 50 µmol, 206 ng/mL for 100 µmol, and 655 ng/mL for 200 µmol. Median skin sulforaphane levels on day 28 were 0.0, 3.1, and 34.1 ng/g for 50, 100, and 200 µmol, respectively. Plasma levels of proinflammatory cytokines decreased from day 1 to 28. The tumor suppressor decorin was increased from day 1 to 28. Oral BSE-SFN is well tolerated at daily doses up to 200 µmol and achieves dose-dependent levels in plasma and skin. A larger efficacy evaluation of 200 µmol daily for longer intervals is now reasonable to better characterize clinical and biological effects of BSE-SFN as chemoprevention for melanoma. Cancer Prev Res; 11(7); 429-38. ©2018 AACR.
Assuntos
Brassica/química , Isotiocianatos/administração & dosagem , Melanoma/prevenção & controle , Nevo/tratamento farmacológico , Extratos Vegetais/administração & dosagem , Neoplasias Cutâneas/tratamento farmacológico , Administração Oral , Adulto , Idoso , Biomarcadores Tumorais/metabolismo , Biópsia , Cápsulas , Estudos de Viabilidade , Feminino , Humanos , Isotiocianatos/efeitos adversos , Isotiocianatos/farmacocinética , Masculino , Melanoma/patologia , Pessoa de Meia-Idade , Nevo/patologia , Extratos Vegetais/efeitos adversos , Extratos Vegetais/farmacocinética , Gravidez , Pele/efeitos dos fármacos , Pele/patologia , Neoplasias Cutâneas/patologia , Sulfóxidos , Distribuição Tecidual , Resultado do Tratamento , Adulto JovemRESUMO
In this perspective, we identify emerging frontiers in clinical and basic research of melanocyte biology and its associated biomedical disciplines. We describe challenges and opportunities in clinical and basic research of normal and diseased melanocytes that impact current approaches to research in melanoma and the dermatological sciences. We focus on four themes: (1) clinical melanoma research, (2) basic melanoma research, (3) clinical dermatology, and (4) basic pigment cell research, with the goal of outlining current highlights, challenges, and frontiers associated with pigmentation and melanocyte biology. Significantly, this document encapsulates important advances in melanocyte and melanoma research including emerging frontiers in melanoma immunotherapy, medical and surgical oncology, dermatology, vitiligo, albinism, genomics and systems biology, epidemiology, pigment biophysics and chemistry, and evolution.
Assuntos
Pesquisa Biomédica , Melanócitos/patologia , Melanoma/patologia , Animais , Modelos Animais de Doenças , Resistencia a Medicamentos Antineoplásicos , Humanos , Melanoma/epidemiologia , Melanoma/prevenção & controle , Melanoma/terapia , PigmentaçãoRESUMO
Oxidative stress plays a role in UV-induced melanoma, which may arise from melanocytic nevi. We investigated whether oral administration of the antioxidant N-acetylcysteine (NAC) could protect nevi from oxidative stress in vivo in the setting of acute UV exposure. The minimal erythemal dose (MED) was determined for 100 patients at increased risk for melanoma. Patients were randomized to receive a single dose (1,200 mg) of NAC or placebo, in double-blind fashion, and then one nevus was irradiated (1-2 MED) using a solar simulator. One day later, the MED was redetermined and the irradiated nevus and a control unirradiated nevus were removed for histologic analysis and examination of biomarkers of NAC metabolism and UV-induced oxidative stress. Increased expression of 8-oxoguanine, thioredoxin reductase-1, and γ-glutamylcysteine synthase modifier subunit were consistently seen in UV-treated compared with unirradiated nevi. However, no significant differences were observed in these UV-induced changes or in the pre- and postintervention MED between those patients receiving NAC versus placebo. Similarly, no significant differences were observed in UV-induced changes between subjects with germline wild-type versus loss-of-function mutations in the melanocortin-1 receptor. Nevi showed similar changes of UV-induced oxidative stress in an open-label post-trial study in 10 patients who received NAC 3 hours before nevus irradiation. Thus, a single oral dose of NAC did not effectively protect nevi from UV-induced oxidative stress under the conditions examined. Cancer Prev Res; 10(1); 36-44. ©2016 AACR.
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Acetilcisteína/uso terapêutico , Antioxidantes/uso terapêutico , Melanoma/prevenção & controle , Nevo Pigmentado/tratamento farmacológico , Estresse Oxidativo/efeitos dos fármacos , Neoplasias Cutâneas/tratamento farmacológico , Raios Ultravioleta/efeitos adversos , Acetilcisteína/administração & dosagem , Acetilcisteína/efeitos adversos , Acetilcisteína/metabolismo , Administração Oral , Antioxidantes/administração & dosagem , Antioxidantes/efeitos adversos , Antioxidantes/metabolismo , Biomarcadores/análise , Método Duplo-Cego , Glutamato-Cisteína Ligase/análise , Guanina/análogos & derivados , Guanina/análise , Humanos , Melanoma/etiologia , Mutação , Nevo Pigmentado/complicações , Nevo Pigmentado/genética , Nevo Pigmentado/patologia , Projetos Piloto , Receptor Tipo 1 de Melanocortina/genética , Neoplasias Cutâneas/complicações , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/patologia , Luz Solar/efeitos adversos , Tiorredoxina Redutase 1/análiseRESUMO
Southern right whales (SRWs, Eubalena australis) are polymorphic for an X-linked pigmentation pattern known as grey morphism. Most SRWs have completely black skin with white patches on their bellies and occasionally on their backs; these patches remain white as the whale ages. Grey morphs (previously referred to as partial albinos) appear mostly white at birth, with a splattering of rounded black marks; but as the whales age, the white skin gradually changes to a brownish grey color. The cellular and developmental bases of grey morphism are not understood. Here we describe cellular and ultrastructural features of grey-morph skin in relation to that of normal, wild-type skin. Melanocytes were identified histologically and counted, and melanosomes were measured using transmission electron microscopy. Grey-morph skin had fewer melanocytes when compared to wild-type skin, suggesting reduced melanocyte survival, migration, or proliferation in these whales. Grey-morph melanocytes had smaller melanosomes relative to wild-type skin, normal transport of melanosomes to surrounding keratinocytes, and normal localization of melanin granules above the keratinocyte nuclei. These findings indicate that SRW grey-morph pigmentation patterns are caused by reduced numbers of melanocytes in the skin, as well as by reduced amounts of melanin production and/or reduced sizes of mature melanosomes. Grey morphism is distinct from piebaldism and albinism found in other species, which are genetic pigmentation conditions resulting from the local absence of melanocytes, or the inability to synthesize melanin, respectively.
Assuntos
Fenótipo , Baleias/anatomia & histologia , Animais , Contagem de Células , Feminino , Masculino , Melanócitos/citologia , Pele/citologia , Pele/ultraestruturaRESUMO
We demonstrate that SCF-KIT signaling induces synthesis and secretion of endothelin-3 (ET3) in human umbilical vein endothelial cells and melanoma cells in vitro, gastrointestinal stromal tumors, human sun-exposed skin, and myenteric plexus of human colon post-fasting in vivo. This is the first report of a physiological mechanism of ET3 induction. Integrating our finding with supporting data from literature leads us to discover a previously unreported pathway of nitric oxide (NO) generation derived from physiological endothelial NO synthase (eNOS) or neuronal NOS (nNOS) activation (referred to as the KIT-ET3-NO pathway). It involves: (1) SCF-expressing cells communicate with neighboring KIT-expressing cells directly or indirectly (cleaved soluble SCF). (2) SCF-KIT signaling induces timely local ET3 synthesis and secretion. (3) ET3 binds to ETBR on both sides of intercellular space. (4) ET3-binding-initiated-ETBR activation increases cytosolic Ca2+, activates cell-specific eNOS or nNOS. (5) Temporally- and spatially-precise NO generation. NO diffuses into neighboring cells, thus acts in both SCF- and KIT-expressing cells. (6) NO modulates diverse cell-specific functions by NO/cGMP pathway, controlling transcriptional factors, or other mechanisms. We demonstrate the critical physiological role of the KIT-ET3-NO pathway in fulfilling high demand (exceeding basal level) of endothelium-dependent NO generation for coping with atherosclerosis, pregnancy, and aging. The KIT-ET3-NO pathway most likely also play critical roles in other cell functions that involve dual requirement of SCF-KIT signaling and NO. New strategies (e.g. enhancing the KIT-ET3-NO pathway) to harness the benefit of endogenous eNOS and nNOS activation and precise NO generation for correcting pathophysiology and restoring functions warrant investigation.
Assuntos
Endotelina-3/metabolismo , Óxido Nítrico/metabolismo , Proteínas Proto-Oncogênicas c-kit/metabolismo , Receptor de Endotelina B/metabolismo , Fator de Células-Tronco/metabolismo , Aterosclerose/patologia , Linhagem Celular Tumoral , Endotélio Vascular/metabolismo , Ensaio de Imunoadsorção Enzimática , Motilidade Gastrointestinal , Tumores do Estroma Gastrointestinal/metabolismo , Tumores do Estroma Gastrointestinal/patologia , Tumores do Estroma Gastrointestinal/fisiopatologia , Homeostase , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Imuno-Histoquímica , Melanoma/patologia , Plexo Mientérico/metabolismo , Invasividade Neoplásica , Óxido Nítrico Sintase Tipo I/metabolismo , Óxido Nítrico Sintase Tipo III/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos , Transdução de Sinais , Pele/metabolismo , Luz Solar , Fatores de Tempo , Regulação para Cima/genética , VasodilataçãoRESUMO
Melanoma is usually apparent on the skin and readily detected by trained medical providers using a routine total body skin examination, yet this malignancy is responsible for the majority of skin cancer-related deaths. Currently, there is no national consensus on skin cancer screening in the USA, but dermatologists and primary care providers are routinely confronted with making the decision about when to recommend total body skin examinations and at what interval. The objectives of this paper are: to propose rational, risk-based, data-driven guidelines commensurate with the US Preventive Services Task Force screening guidelines for other disorders; to compare our proposed guidelines to recommendations made by other national and international organizations; and to review the US Preventive Services Task Force's 2016 Draft Recommendation Statement on skin cancer screening.
RESUMO
Paclitaxel and docetaxel can induce pro-inflammatory proteins, typified by cyclooxygenase-2 (prostaglandin H synthase). In some circumstances, this phenomenon may be relevant to the immunomodulatory actions and the adverse effects associated with paclitaxel or docetaxel. Accordingly, we compared a panel of sixteen taxanes, including paclitaxel and docetaxel, for their ability to induce cyclooxygenase-2 in a murine macrophage cell line (RAW 264.7) and in human peripheral blood monocytes. We discovered that the structure-activity relationships governing the induction of cyclooxygenase-2 protein differ markedly between the two species. Of 14 analogues evaluated, only 2 had activity comparable with paclitaxel in RAW 264.7 cells. In contrast, docetaxel and 12 of 14 analogues had activity comparable with paclitaxel in human monocytes. Our results enabled us to predict and subsequently affirm that the major human hepatic metabolite, 6alpha-hydroxypaclitaxel, would induce cyclooxygenase-2 in human cells but not in murine cells. Our structure-activity data and our experiments with combinations of taxanes suggest a provisional model for cyclooxygenase-2 induction. This model suggests that binding at a high-affinity site on tubulin and stabilization of microtubules is necessary, but not sufficient, for cyclooxygenase-2 induction. Binding at a second, lower-affinity receptor site is also necessary. However, our structure activity data are not fully compatible with two candidate proteins currently proposed as the low-affinity receptor.