Pigment Cell & Melanoma Research最新文献

Post-inflammatory hyperpigmentation (PIH) is a very common disorder of cutaneous hyperpigmentation, which poses a persistent management challenge in the fields of dermatology and esthetics. This study was designed to explore the anti-melanogenic and anti-inflammatory effects of Bay 11-7082, an NF-κB inhibitor, using small-molecule screening, to determine its potential application for PIH prevention. The molecular mechanisms were investigated in vitro and ex vivo in epidermis-humanized mice using melanin content, RT-PCR, and immunoblotting. Bay 11-7082 suppressed proinflammatory cytokines and ameliorated 2,4-dinitrofluorobenzene (DNFB)-induced contact dermatitis on day 15. The suppression of melanin synthesis by Bay 11-7082 was attributed to the reduction of MITF, which was induced by extracellular signal-regulated kinase activation. Bay 11-7082 reduced epidermal melanin accumulation in UVB-stimulated ex vivo human epidermis as well as in the ear and tail skin of K14-stem cell factor (SCF) transgenic mice. Topical administration of Bay 11-7082 improved PIH on day 35 in the post-DNFB dorsal skin of K14-SCF transgenic mice. In conclusion, Bay 11-7082 can be considered a promising candidate for the development of a preventive topical agent for PIH.

The 2023 Cure Ocular Melanoma (CURE OM) Global Science Meeting was held in Philadelphia on November 6, 2023. There is increased awareness and dedicated research in uveal melanoma (UM), but unmet needs remain in the prevention, detection, and treatment of UM. The purpose of this meeting was to provide an international forum for the exchange of research ideas, to allow for discussion of basic science as well as clinical research on UM, and to gather input about advocacy and patient needs.

Current NICE guidelines state that in high-risk melanoma patients, imaging should not be offered before SLNB unless lymph node or distant metastases are suspected. Our experience has been that in patients with pT3b, pT4a and pT4b melanomas, the rate of management-changing findings on axial imaging prior to SLNB was high and that 'stage before operating' is a better approach. We now offer full axial imaging as staging to all high-risk melanoma patients prior to SLNB and advise other skin cancer MDTs to follow this approach.

Human pigmentary disorders encompass a broad spectrum of phenotypic changes arising from disruptions in various stages of melanocyte formation, the melanogenesis process, or the transfer of pigment from melanocytes to keratinocytes. A large number of pigmentation genes associated with pigmentary disorders have been identified, many of them awaiting in vivo confirmation. A more comprehensive understanding of the molecular basis of pigmentary disorders requires a vertebrate animal model where changes in pigmentation are easily observable in vivo and can be combined to genomic modifications and gain/loss-of-function tools. Here we present the amphibian Xenopus with its unique features that fulfill these requirements. Changes in pigmentation are particularly easy to score in Xenopus embryos, allowing whole-organism based phenotypic screening. The development and behavior of Xenopus melanocytes closely mimic those observed in mammals. Interestingly, both Xenopus and mammalian skins exhibit comparable reactions to ultraviolet radiation. This review highlights how Xenopus constitutes an alternative and complementary model to the more commonly used mouse and zebrafish, contributing to the advancement of knowledge in melanocyte cell biology and related diseases.

UVA radiation, a primary risk factor in melanoma progression, partly acts through the mediation of reactive oxygen species (ROS). The role of ROS in driving cutaneous melanoma toward an invasive phenotype and whether it occurs through opsins (OPNs), which are photosensitive G protein-coupled receptors, is not fully understood. This study focuses on the impact of UVA radiation on melanoma cell proliferation, with a special emphasis on OPN3. Investigating the biphasic response to various UVA doses (0.75-9 J/cm²) in A375 and MV3 cell lines, and using EdU and CCK-8 assays, we observed dose-dependent changes in cell proliferation. Interestingly, UVA irradiation at these doses of 0.75, 1.5 and 3 J/cm² did not significantly induce ROS production. Our study further delves into the role of OPN3, a photosensitive receptor, in melanoma progression. Following UVA exposure, an increase in OPN3 expression was observed in melanoma cells lines A375 and MV3, indicating its role as a UVA-sensitive sensor and its influence on cell proliferation. Additionally, UVA-induced calcium flux in two melanoma cells lines pointed to a calcium-dependent G protein-coupled pathway in melanoma proliferation, mediated by OPN3 and not reliant on ROS. This research sheds light on the mechanism of UVA-induced melanoma progression, underscoring OPN3 as a pivotal regulator and advancing our understanding of UVA's interaction with opsins in melanoma progression.

Marked differences in survival from melanoma are noted between men and women that cannot be accounted for by behavioral differences. We and others have provided evidence that this difference may be due to increased expression of immune-related genes from the second X chromosome because of failure of X inactivation. In the present review, we have examined evidence for the contrary view that survival differences are due to weaker immune responses in males. One reason for this may be the loss of Y chromosomes (LOY), particularly in older males. The genes involved may have direct roles in immune responses or be noncoding RNAs that regulate both sex and autosomal genes involved in immune responses or tumor growth. Loss of the KDM6C and KDM5D demethylases appeared to common genes involved. The second factor appears to be the activation of androgen receptors (AR) on melanoma cells that increase their invasiveness and growth. Induction of T-cell exhaustion by AR that limits immune responses against melanoma appeared a common finding. The development of treatments to overcome effects related to gene loss on Y poses challenges, but several avenues related to AR signaling appear worthy of further study in the treatment of metastatic disease.

Metabolic syndrome (MetS) remains a significant global public health concern. However, the relationship between MetS, its individual components and melanoma metastasis remains unexplored. We analysed the clinical data of 258 Chinese melanoma patients who had not undergo systemic therapy. Binary logistic regression, adjusted for sex and age, was employed to evaluate the connection between MetS and its components and melanoma metastasis. Of the 258 melanoma patients, 92 met the MetS criteria upon diagnosis. No direct association between MetS and melanoma metastasis was identified. However, specific components of MetS, namely low HDL-cholesterol levels (OR = 2.85, 95% CI:1.50-5.41, p < 0.05) and dysglycaemia (OR = 4.23, 95% CI:1.80-8.96, p < 0.05), were associated with melanoma metastasis. In subgroup analysis, hypertriglyceridemia correlated with melanoma metastasis in non-elderly patients (< 65 years) (OR = 2.69, 95% CI: 1.14-6.33, p < 0.05). Central obesity and hypertension showed no association. A dose-response analysis further indicated that melanoma metastasis risk escalated with increasing fasting blood glucose and blood triglyceride concentrations, and with decreasing blood HDL concentration. Our results suggest that monitoring and managing individual components of the MetS, particularly HDL-cholesterol levels, fasting glucose and triglyceride levels, may have potential prognostic benefits for melanoma in the Chinese population.

Lipid droplets are fat storage organelles composed of a protein envelope and lipid-rich core. Regulation of this protein envelope underlies differential lipid droplet formation and function. In melanoma, lipid droplet formation has been linked to tumor progression and metastasis, but it is unknown whether lipid droplet proteins play a role. To address this, we performed proteomic analysis of the lipid droplet envelope in melanoma. We found that lipid droplet proteins were differentially enriched in distinct melanoma states; from melanocytic to undifferentiated. DHRS3, which converts all-trans-retinal to all-trans-retinol, is upregulated in the MITF^LO/undifferentiated/neural crest-like melanoma cell state and reduced in the MITF^HI/melanocytic state. Increased DHRS3 expression is sufficient to drive MITF^HI/melanocytic cells to a more undifferentiated/invasive state. These changes are due to retinoic acid-mediated regulation of melanocytic genes. Our data demonstrate that melanoma cell state can be regulated by expression of lipid droplet proteins which affect downstream retinoid signaling.

Vitiligo is an autoimmune disorder characterized by chronic depigmentation and milk-white patches on the skin. Skin infiltration by autoreactive CD8⁺ T cells causes melanocyte destruction in vitiligo. Multiple risk factors, particularly immune-related inflammatory factors, are involved in the disappearance of melanocytes. LL37 is a classic damage-associated molecular pattern molecule that is involved in the development of various autoimmune diseases. An enhanced expression of LL37 in vitiligo is known; however, the exact role of LL37 in melanocyte loss has not yet been elucidated. In the present study, we detected increased LL37 expression in vitiligo serum and lesions. Furthermore, we confirmed that cultured keratinocytes released LL37 after treatment with H₂O₂. Moreover, the LL37-DNA complex enhanced the secretion of CXCL9, CXCL10, and CXCL16 from keratinocytes via the TLR9-MyD88 signaling pathway and facilitated the migration of CD8⁺ T cells. Altogether, our study demonstrates that LL37 released from keratinocytes binds to DNA and contributes to melanocyte destruction under oxidative stress-induced autoimmunity in vitiligo.

Both germline and somatic variants contribute to the genetic background and pathogenesis of melanoma. Germline variants include the presence of rare pathogenic or likely pathogenic variants of high, medium, and low penetrance melanoma-predisposing genes. Rare variants of high penetrance melanoma-predisposing genes are associated with melanoma development, whereas the medium and low penetrance predisposing genes can significantly increase melanoma risk. In this study, we clarified the germline genetic background of a Hungarian melanoma cohort (n = 17). Using a gene panel of 30 melanoma-predisposing genes, germline genetic variants were identified in 10 of the 17 patients (58.82%). A novel, likely pathogenic, missense variant (p.Y143C) in a medium penetrance melanoma-predisposing gene, melanocortin 1 receptor gene (MC1R), and two novel, likely pathogenic nonsense variants in low penetrance genes, p.Q218Ter in caspase 8 (CASP8) and p.Q40Ter in the fat mass- and obesity-associated (FTO) gene were detected. This study highlights the importance of elucidating the germline genetic background of melanoma, which may improve prediction of individual risk and the risk of family members and to optimize preventive, screening, and therapeutic measures for each patient and melanoma-prone families.