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Journal of the European Academy of... Jun 2024Only a small per cent of new melanocytic lesions developing in adults are expected to represent melanomas. Total body photography (TBP) has been widely incorporated in...
BACKGROUND
Only a small per cent of new melanocytic lesions developing in adults are expected to represent melanomas. Total body photography (TBP) has been widely incorporated in clinical practice, especially for follow-up of high-risk individuals with multiple naevi. However, dynamic changes detected with TBP need to be interpreted with caution to avoid unnecessary excisions.
OBJECTIVES
To identify clinical and dermoscopic predictors of malignancy in melanocytic lesions presenting clinically as new lesions on TBP.
METHODS
Melanomas and melanocytic naevi excised from a high-risk cohort and presenting as new lesions on TBP were retrospectively included. Naevi were arbitrarily collected up to approximately twice the number of melanomas. Melanomas were categorized as 'unequivocal' or 'borderline' on histopathology review.
RESULTS
Sixty melanomas and 110 naevi were included. Median age (range) of cases (55; 27-83) was 9 years older than controls (46; 24-77) (p < 0.0001). Median diameter (IQR) of naevi was 2.6 mm (1.8-3.8) and of melanomas 4.2 mm (2.7-7.0) (p < 0.0001). On histopathology, 40% of the melanomas were 'borderline'. A positive 7-point checklist was reported in 12.5% of 'borderline' melanomas and 33.3% of 'unequivocal' melanomas (p = 0.005), while 18.3% of melanomas were completely featureless. Blue-whitish veil, atypical vascular pattern and shiny white lines were exclusively found in melanomas. The main predictors of malignancy were (OR; 95% CI) regression structures (7.13; 1.88-27.06; p = 0.004); hypo/amelanotic colour (6.00; 1.17-30.73; p = 0.03); irregular pigmentation (3.89; 1.36-11.13; p = 0.01); asymmetrical peripheral dots/globules (3.50; 1.11-11.00; p = 0.03); and asymmetry in pattern and/or colour (2.5; 1.3-4.9; p = 0.007). All invasive melanomas detected in patients younger than 50 years presented at least one dermoscopic predictor of malignancy.
CONCLUSIONS
Melanomas presenting as new lesions are frequently featureless or feature poor on dermoscopy and difficult-to-diagnose on histopathology. In high-risk patients, the presence on any of the dermoscopic predictors of malignancy identified should prompt excision; however, the remaining lesions should be closely monitored.
PubMed: 38925576
DOI: 10.1111/jdv.20188 -
International Immunopharmacology Jun 2024Melanoma is a skin cancer originating from melanocytes. The global incidence rate of melanoma is rapidly increasing, posing significant public health challenges....
Melanoma is a skin cancer originating from melanocytes. The global incidence rate of melanoma is rapidly increasing, posing significant public health challenges. Identifying effective therapeutic agents is crucial in addressing this growing problem. Natural products have demonstrated promising anti-tumor activity. In this study, a plant flavonoid, taxifolin, was screened using Weighted Correlation Network Analysis (WGCNA) in combination with the Connectivity Map (CMAP) platform. Taxifolin was confirmed to inhibit the proliferation, migration, and invasion ability of melanoma A375 and MV-3 cells by promoting apoptosis. Additionally, it suppressed the Epithelial-Mesenchymal Transition (EMT) process of melanoma cells. Cyber pharmacological analysis revealed that taxifolin exerts its inhibitory effect on melanoma through the PI3K/AKT signaling pathway, specifically by downregulating the protein expression of p-PI3K and p-AKT. Notably, the addition of SC-79, an activator of the PI3K/AKT signaling pathway, reversed the effects of taxifolin on cell migration and apoptosis. Furthermore, in vivo experiments demonstrated that taxifolin treatment slowed tumor growth in mice without significant toxic effects. Based on these findings, taxifolin holds promise as a potential drug for melanoma treatment.
PubMed: 38924866
DOI: 10.1016/j.intimp.2024.112517 -
International Journal of Cosmetic... Jun 2024Methylsulfonylmethane (MSM), which contains organic sulphur, has been used for a long time as a medicinal ingredient because of its benefits to human health. MSM is...
OBJECTIVE
Methylsulfonylmethane (MSM), which contains organic sulphur, has been used for a long time as a medicinal ingredient because of its benefits to human health. MSM is reported to be protective against certain skin disorders, but it is unknown whether it affects melanin synthesis. Therefore, in our current research, we examined the possibility of MSM controlling the production of melanin in Mel-Ab melanocytes.
METHODS
In Mel-Ab cells, melanin contents and tyrosinase activities were assessed and quantified. The expression of microphthalmia-associated transcription factor (MITF) and tyrosinase was evaluated using western blot analysis, while MSM-induced signalling pathways were investigated.
RESULTS
The MSM treatment significantly resulted in a dose-dependent increase in melanin production. Furthermore, MSM elevated melanin-related proteins, including MITF and tyrosinase. However, the rate-limiting enzyme of melanin production, tyrosinase, was not directly influenced by it. Therefore, we investigated potential melanogenesis-related signalling pathways that may have been triggered by MSM. Our findings showed that MSM did not influence the signalling pathways associated with glycogen synthase kinase 3β, cAMP response-element binding protein, extracellular signal-regulated kinase, or p38 mitogen-activated protein kinase. However, MSM phosphorylated c-Jun N-terminal kinases/stress-activated protein kinase (JNK/SAPK), which is known to induce melanogenesis. SP600125, a specific JNK inhibitor, inhibited MSM-induced melanogenesis.
CONCLUSION
Taken together, our study indicates that MSM induces melanin synthesis and may serve as a therapeutic option for hypopigmentary skin disorders such as vitiligo.
PubMed: 38924609
DOI: 10.1111/ics.12988 -
Proteins Jun 2024The MC1R protein is a receptor found in melanocytes that plays a role in melanin synthesis. Mutations in this protein can impact hair color, skin tone, tanning ability,...
The MC1R protein is a receptor found in melanocytes that plays a role in melanin synthesis. Mutations in this protein can impact hair color, skin tone, tanning ability, and increase the risk of skin cancer. The MC1R protein is activated by the alpha-melanocyte-stimulating hormone (α-MSH). Previous studies have shown that mutations affect the interaction between MC1R and α-MSH; however, the mechanism behind this process is poorly understood. Our study aims to shed light on this mechanism using molecular dynamics (MD) simulations to analyze the Asp84Glu and Asp294His variants. We simulated both the wild-type (WT) protein and the mutants with and without ligand. Our results reveal that mutations induce unique conformations during state transitions, hindering the switch between active and inactive states and decreasing cellular levels of cAMP. Interestingly, Asp294His showed increased ligand affinity but decreased protein activity, highlighting that tighter binding does not always lead to increased activation. Our study provides insights into the molecular mechanisms underlying the impact of MC1R mutations on protein activity.
PubMed: 38923677
DOI: 10.1002/prot.26722 -
Annals of the New York Academy of... Jun 2024This study aimed to investigate the protective effect of NAcM-OPT, a small molecule inhibitor of defective in cullin neddylation 1 (DCN1), on HO-induced oxidative damage...
This study aimed to investigate the protective effect of NAcM-OPT, a small molecule inhibitor of defective in cullin neddylation 1 (DCN1), on HO-induced oxidative damage in keratinocytes. Immortalized human keratinocytes (HaCaT cells) were treated with NAcM-OPT and exposed to oxidative stress. CCK-8 assays were used to measure cell viability. The mGFP-RFP-LC3 dual fluorescent autophagy indicator system was utilized to evaluate changes in autophagic flux. Western blotting was used to measure the expression of the autophagy-related proteins LC3 and Beclin 1. Keratinocytes were treated with the autophagy activator rapamycin, and HaCaT cell supernatant was added to PIG1 cells (immortalized human melanocytes), followed by evaluation of tyrosinase (TYR) expression via qRT-PCR. NAcM-OPT increased cell viability and cell proliferation. Furthermore, this molecule promoted autophagic flux through increased expression of autophagy-related proteins under HO-induced oxidative stress. Additionally, rapamycin increased the mRNA levels of TYR in PIG1 cells. Moreover, NAcM-OPT alleviated mitochondrial damage, restored mitochondrial function, and upregulated the expression of NFE2L2, HO1, NQO1, and GCLM. Importantly, NAcM-OPT also increased epidermal thickness, follicle length, and melanin synthesis under oxidative stress in vivo. These findings suggest that NAcM-OPT may be a promising small molecule antioxidant drug for the treatment of vitiligo.
PubMed: 38922711
DOI: 10.1111/nyas.15173 -
Hematology Reports Jun 2024Hypopigmentation disorders pose significant diagnostic challenges in dermatology, sometimes reflecting underlying hematological conditions. This review explores the... (Review)
Review
Hypopigmentation disorders pose significant diagnostic challenges in dermatology, sometimes reflecting underlying hematological conditions. This review explores the clinical presentations related to hypopigmentation in hematological disorders, focusing on vitiligo, morphea, and syndromic albinism. Vitiligo, an autoimmune disorder targeting melanocytes, involves interactions between genetic polymorphisms and immune responses, particularly regarding CD8+ T cells and IFN-γ. Drug-induced vitiligo, notably by immune checkpoint inhibitors and small-molecule targeted anticancer therapies, underscores the importance of immune dysregulation. Morphea, an inflammatory skin disorder, may signal hematological involvement, as seen in deep morphea and post-radiotherapy lesions. Syndromic albinism, linked to various genetic mutations affecting melanin production, often presents with hematologic abnormalities. Treatment approaches focus on targeting the immune pathways specific to the condition, and when that is not possible, managing symptoms. Understanding these dermatological manifestations is crucial for the timely diagnosis and management of hematological disorders.
PubMed: 38921184
DOI: 10.3390/hematolrep16020036 -
Current Issues in Molecular Biology May 2024Melanocytes, located in the epidermis' basal layer, are responsible for melanin pigment production, crucial for skin coloration and protection against UV...
Melanocytes, located in the epidermis' basal layer, are responsible for melanin pigment production, crucial for skin coloration and protection against UV radiation-induced damage. Melanin synthesis is intricately regulated by various factors, including the Wnt signaling pathway, particularly mediated by the microphthalmia-associated transcription factor (MITF). While MITF is recognized as a key regulator of pigmentation, its regulation by the Wnt pathway remains poorly understood. This study investigates the role of Sfrp5pepD, a peptide antagonist of the Wnt signaling pathway, in modulating melanogenesis and its potential therapeutic implications for pigmentary disorders. To tackle this issue, we investigated smaller peptides frequently utilized in cosmetics or pharmaceuticals. Nevertheless, there is a significant scarcity of reports on peptides associated with melanin-related signal modulation or inhibiting melanin production. Results indicate that Sfrp5pepD effectively inhibits Wnt signaling by disrupting the interaction between Axin-1 and β-catenin, thus impeding downstream melanogenic processes. Additionally, Sfrp5pepD suppresses the interaction between MITF and β-catenin, inhibiting their nuclear translocation and downregulating melanogenic enzyme expression, ultimately reducing melanin production. These inhibitory effects are validated in cell culture models suggesting potential clinical applications for hyperpigmentation disorders. Overall, this study elucidates the intricate interplay between Wnt signaling and melanogenesis, highlighting Sfrp5pepD as a promising therapeutic agent for pigmentary disorders. Sfrp5pepD, with a molecular weight of less than 500 Da, is anticipated to penetrate the skin unlike SFRPs. This suggests a strong potential for their use as cosmetics or transdermal absorption agents. Additional investigation into its mechanisms and clinical significance is necessary to enhance its effectiveness in addressing melanin-related skin conditions.
PubMed: 38920996
DOI: 10.3390/cimb46060324 -
The American Journal of Dermatopathology Jun 2024Ambiguous melanocytic lesions/tumors (AMLs) can be simply described as melanocytic neoplasms that cannot be differentiated as either a melanoma or a nevus....
Ambiguous melanocytic lesions/tumors (AMLs) can be simply described as melanocytic neoplasms that cannot be differentiated as either a melanoma or a nevus. Preferentially expressed antigen in melanoma (PRAME) is a novel antibody that can help differentiate between nevi and melanomas. However, its usefulness remains controversial in AMLs. The aim of this study was to demonstrate the importance of PRAME and diagnostic auxiliary antibodies (Ki-67, p16, HMB-45) in the diagnosis of melanocytic lesions, especially in AMLs. This study included 52 ambiguous melanocytic lesions, 40 nevi, and 40 melanomas. All immunohistochemical studies were performed automatically using the Universal Alkaline Phosphatase Red Detection Kit. Different analytic approaches were used for each antibody based on the literature. Statistically, the multinomial forward stepwise elimination logistic regression analysis was used to create a statistical model to predict the diagnosis of melanocytic lesions based on clinical, morphological, and immunohistochemical data. PRAME positivity was very strong and diffuse in the melanoma group and statistically significantly higher than that of the AML and nevus groups. There was no statistically significant difference between the nevus and AML groups. The Ki-67 proliferation index and HMB-45 staining pattern provided valuable indications for distinguishing between these 3 groups. The P16 antibody was limited in supporting the differential diagnosis. Our statistical model showed that a high mitosis count, central pagetoid spread, and PRAME positivity increased the probability of melanoma against an AML diagnosis. This study showed the advantages of evaluating the PRAME antibody together with morphological features and other immunohistochemical markers (Ki-67 and HMB-45) in the differential diagnosis of melanocytic lesions.
PubMed: 38916203
DOI: 10.1097/DAD.0000000000002768 -
Melanoma Research Jun 2024Vulvar melanoma is considered rare, but it is the second most frequent vulvar neoplasm; 2% of melanomas in women arise in the vulvar area. It is important to highlight...
Vulvar melanoma is considered rare, but it is the second most frequent vulvar neoplasm; 2% of melanomas in women arise in the vulvar area. It is important to highlight how the characteristics of vulvar melanoma differentiate it from classic cutaneous melanoma. Vulvar melanoma has different risk factors and clinical and dermoscopic characteristics; moreover, it has a higher recurrence rate and a greater likelihood of multifocality. Here, we present a case of a 44-year-old patient with two primary vulvar melanomas located on opposite sides of her vulva. The lesions were both flat, but they had distinct clinical and dermoscopic appearances. Melanoma of the genital tract is likely the result of a multifocal disorder of the melanocytes within the mucosa that inhabit the perineal squamous epithelium. The risk factors of vulvar melanoma differ from those of classical cutaneous melanomas. Vulvar melanoma occurs in an area shielded from ultraviolet radiation; the primary risk factors include chronic inflammatory disease, genetic susceptibility, irritant agents and viral infections. This case study reveals how a close examination of the genital area is important and how dermoscopy can aid in the differential diagnosis of vulvar lesions. Inspections of the genital area should be particularly thorough if a melanoma is detected there, given the higher risk of multifocality in that part of the body.
PubMed: 38913418
DOI: 10.1097/CMR.0000000000000989 -
Toxicological Research Jul 2024Phthalates are extensively employed plasticizers crucial for conferring flexibility and plasticity to polyvinyl chloride. Phthalates, including DEHP...
Phthalates are extensively employed plasticizers crucial for conferring flexibility and plasticity to polyvinyl chloride. Phthalates, including DEHP (di(2-ethylhexyl)phthalate), present in diverse products, have been identified in fine dust and are capable of infiltrating the body, potentially posing health hazards. Importantly, melanocytes, existing at the basal layer of the epidermis, are susceptible to toxic substances. In our study, we employed the 3D human pigmented epidermis model, MelanoDerm™, along with the B16F10 murine melanoma cell line, to examine the influence of DEHP exposure on melanocytes. The exposure to low concentrations of DEHP (~ 5 μM), resulted in the extension of melanocyte dendrites, indicating the stimulation of melanocytes. Analysis of gene expression and protein profiles unveiled the up-regulation of MITF, Arpc2, and TRP1 genes subsequent to DEHP exposure, indicating alterations in cytoskeletal and melanosome-related genetic and protein components in melanocytes. Notably, increased pigmentation was observed in MelanoDerm™ following DEHP exposure. DEHP-stimulated reactive oxygen species generation appeared to be involved in these events since the antioxidant, ascorbic acid attenuated ROS generation and MITF upregulation. Collectively, our study demonstrated that DEHP exposure can induce cytoskeletal disturbance and skin pigmentation through oxidative stress.
PubMed: 38911535
DOI: 10.1007/s43188-024-00240-5