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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., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Checkpoint inhibitors, specifically anti-programmed cell death protein 1 (PD1), have shown success in treating metastatic melanoma; however, some patients develop resistance. Dendritic cells (DC) play a key role in initiating an immune response, but in certain circumstances they become ineffective. We investigated the role of MerTK, a receptor tyrosine kinase responsible for myeloid cell clearance of dead cells, in the regulation of DC function and metabolism in the tumor microenvironment. Tumors resistant to anti-PD1 exhibited increased levels of MerTK+ DCs. Treating wild-type DCs with apoptotic melanoma cells in vitro resulted in increased MerTK expression, elevated mitochondrial respiration and fatty acid oxidation, and reduced T-cell stimulatory capacity, all characteristics of dysfunctional DCs. In contrast, dead cells had only limited effect on the metabolism of MerTK-deficient DCs, which instead maintained an antigen-presenting, stimulatory phenotype. The efficacy of anti-PD1 to slow tumor progression and induce antigen specific T-cell infiltration was markedly increased in mice with selective ablation of MerTK in the DC compartment, suggesting the possibility of therapeutically targeting MerTK to modulate DC metabolism and function and enhance anti-PD1 therapy., (©2024 American Association for Cancer Research.)

Positron emission tomography (PET) is a powerful tool for investigating the in vivo behavior of drug delivery systems. We aimed to assess the biodistribution of extracellular vesicles (EVs), nanosized vesicles secreted by cells isolated from various human cell sources using PET. EVs were isolated from mesenchymal stromal cells (MSCs) (MSC EVs), human macrophages (Mϕ EVs), and a melanoma cell line (A375 EVs) by centrifugation and were conjugated with deferoxamine for radiolabeling with Zr-89. PET using conjugated and radiolabeled EVs evaluated their in vivo biodistribution and tissue tropisms. Our study also investigated differences in mouse models, utilizing immunocompetent and immunocompromised mice and an A375 xenograft tumor model. Lastly, we investigated the impact of different labeling techniques on the observed EV biodistribution, including covalent surface modification and membrane incorporation. PET showed that all tested EVs exhibited extended in vivo circulation and generally low uptake in the liver, spleen, and lungs. However, Mϕ EVs showed high liver uptake, potentially attributable to the intrinsic tissue tropism of these EVs from the surface protein composition. MSC EV biodistribution differed between immunocompetent and immunodeficient mice, with increased spleen uptake observed in the latter. PET using A375 xenografts demonstrated efficient tumor uptake of EVs, but no preferential tissue-specific tropism of A375 EVs was found. Biodistribution differences between labeling techniques showed that surface-conjugated EVs had preferential blood circulation and low liver, spleen, and lung uptake compared to membrane integration. This study demonstrates the potential of EVs as effective drug carriers for various diseases, highlights the importance of selecting appropriate cell sources for EV-based drug delivery, and suggests that EV tropism can be harnessed to optimize therapeutic efficacy. Our findings indicate that the cellular source of EVs, labeling technique, and animal model can influence the observed biodistribution.

Background/aim: Over-expression of glucose transporters (GLUTs), membrane proteins that facilitate glucose transport, has been implicated in cutaneous melanomas. Our prior studies have demonstrated increased expression of GLUT1 and GLUT3 in melanomas and their association with poorer prognosis. This study aimed to investigate the expression of GLUT isoforms 4 and 8 in melanocytic lesions, examine the co-expression status of multiple GLUTs, and evaluate their prognostic significance., Materials and Methods: We analyzed 171 melanocytic lesions (97 primary melanomas, 19 metastatic melanomas, and 55 nevi) using a tissue microarray and immunohistochemistry using antibodies against GLUT4 and GLUT8. Membranous expression of GLUTs was scored using a semi-quantitative method. A combined GLUT total score was generated by summing scores from GLUT1, GLUT3, GLUT4, and GLUT8 (including data from previous studies)., Results: A significant up-regulation of GLUT4 and GLUT8 expression was found in melanomas compared to nevi (p<0.0001 for both). Concurrent over-expression of multiple GLUTs was more prevalent in melanomas compared to nevi (p<0.0001), and it was also more frequent in metastatic melanomas compared to primary melanomas (p=0.047). Importantly, high total GLUT expression scores were significantly correlated with negative prognostic factors, such as ulceration and mitoses (p=0.03 and p=0.008 respectively). Additionally, Kaplan-Meier survival curves revealed that patients with elevated GLUT total score in their melanomas had a lower disease-specific survival (p=0.006). Furthermore, analysis of multiple GLUTs improved diagnostic sensitivity., Conclusion: Similar to GLUT1 and GLUT3, melanoma exhibits up-regulation of GLUT 4 and GLUT8 compared to nevi. Evaluation of multiple GLUT isoforms improves diagnostic and prognostic values., (Copyright © 2024 International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Background/aim: Uveal melanoma (UM) represents a prevailing primary intraocular malignancy, with a limited median overall survival among metastatic patients, and most tumors lack RAF/RAS mutations. The pan-RAF inhibitor LY3009120 has demonstrated valuable anti-tumor effects in a wide range of RAF/RASmut and wild-type (WT) tumor models. This study aimed to evaluate the antitumor effect of LY3009120 on 92-1 UM cell line., Materials and Methods: The effect of the pan-RAF inhibitor LY3009120 on cell proliferation, metabolic activity, biomass, early and late apoptosis/necrosis, and morphology was characterized in vitro (0.1-5 μM for 48 h/72 h). Furthermore, targeted panel sequencing was used to characterize the mutational landscape of the human 92-1 UM cell line., Results: LY3009120 showed a significant concentration-dependent anti-proliferative effect on 92-1 cells. Cell proliferation and viability were significantly reduced at the lowest effective concentration of 0.5 μM (at 48 and 72 h, p<0.001). Furthermore, LY3009120 caused significant early apoptosis and late apoptosis/necrosis in 92-1 cells at 5 μM. Except for TP53, NGS showed that all 49 additional analysed genes (Oncomine myeloid panel) of 92-1 were wild-type, including BRAF, NRAS, and KRAS., Conclusion: The pan-RAF inhibitor LY3009120 demonstrated a significant anti-tumor effect on human UM cell line 92-1 independent of the molecular BRAF and RAS mutational status., (Copyright © 2024 International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Background/aim: Malignant melanoma is a tumor with a poor prognosis that can metastasize distally at an early stage. Terrein, a metabolite produced by Aspergillus terreus, suppresses the expression of angiogenin, an angiogenic factor. However, the pharmacological effects of natural terrein have not been elucidated, because only a small amount of terrein can be extracted from large fungal cultures. In this study, we investigated the antineoplastic effects of terrein on human malignant melanoma cells and its underlying mechanisms., Materials and Methods: Human malignant melanoma cell lines were cultured in the presence of terrein and analyzed. Angiogenin production was evaluated using ELISA. Ribosome biosynthesis was evaluated using silver staining of the nucleolar organizer region. Intracellular signaling pathways were analyzed using western blotting. Malignant melanoma cells were transplanted subcutaneously into the backs of nude mice. The tumors were removed at 5 weeks and analyzed histopathologically., Results: Terrein inhibited angiogenin expression, proliferation, migration, invasion, and ribosome biosynthesis in malignant melanoma cells. Terrein was shown to inhibit tumor growth and angiogenesis in animal models., Conclusion: This study demonstrated that terrein has anti-tumor effects against malignant melanoma. Furthermore, chemically synthesized non-natural terrein can be mass-produced and serve as a novel potential anti-tumor drug candidate., (Copyright © 2024, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Immune checkpoint inhibition has transformed the treatment landscape of advanced melanoma and long-term survival of patients is now possible. However, at least half of the patients do not benefit sufficiently. Metabolic reprogramming is a hallmark of cancer cells and may contribute to both tumour growth and immune evasion by the tumour. Preclinical studies have indeed demonstrated that modulating tumour metabolism can reduce tumour growth while improving the functionality of immune cells. Since metabolic pathways are commonly shared between immune and tumour cells, it is essential to understand how modulating tumour metabolism in patients influences the intricate balance of pro-and anti-tumour immune effects in the tumour microenvironment. The key question is whether modulating tumour metabolism can inhibit tumour cell growth as well as facilitate an anti-tumour immune response. Here, we review current knowledge on the effect of tumour metabolism on the immune response in melanoma. We summarise metabolic pathways in melanoma and non-cancerous cells in the tumour microenvironment and discuss models and techniques available to study the metabolic-immune interaction. Finally, we discuss clinical use of these techniques to improve our understanding of how metabolic interventions can tip the balance towards a favourable, immune permissive microenvironment in melanoma patients., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Abstract: Melanocyte differentiation antigens refer to molecules expressed in cells of melanocytic lineage such as gp100/PMEL, tyrosinase, and Melan-A. Corresponding antibodies such as HMB45, T311, and A103 have become key immunohistochemical tools in surgical pathology for the diagnosis of pigmented and related lesions. Little is known about tyrosinase-related protein 1 (TRP1), another melanocyte differentiation antigen, which is an enzymatic component of melanogenesis and known as the brown locus in mice. In this study, we tested several commercial reagents to TRP1 and identified one clone, EPR13063, which we further characterized by testing its specificity and usefulness for surgical pathology. Subsequently, we analyzed the expression of TRP1 in panels of normal tissues and tumors. TRP1 is regularly expressed in normal skin and in cutaneous nevi predominantly present in junctional and to a lesser extent in dermal nevocytes. In melanoma, TRP1 is present in 100% and 44% of primary and metastatic melanomas, respectively. TRP1 was absent in 5 desmoplastic melanomas but heterogeneously present in 9 of 11 PEComas/angiomyolipomas. No TRP1 was found in neoplasms of nonmelanocytic lineage. We demonstrate that EPR13063 is a valuable reagent for the analysis of TRP1 expression in archival surgical pathology material. The TRP1 expression pattern in melanocytic and related lesions appears to parallel other melanocyte differentiation antigens with a higher incidence in primary and a lower incidence in metastatic melanomas., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Melanoma metabolism can be reprogrammed by activating BRAF mutations. These mutations are present in up to 50% of cutaneous melanomas, with the most common being V600E. BRAF mutations augment glycolysis to promote macromolecular synthesis and proliferation. Prior to the development of targeted anti-BRAF therapies, these mutations were associated with accelerated clinical disease in the metastatic setting. Combination BRAF and MEK inhibition is a first line treatment option for locally advanced or metastatic melanoma harboring targetable BRAF mutations. This therapy shows excellent response rates but these responses are not durable, with almost all patients developing resistance. When BRAF mutated melanoma cells are inhibited with targeted therapies the metabolism of those cells also changes. These cells rely less on glycolysis for energy production, and instead shift to a mitochondrial phenotype with upregulated TCA cycle activity and oxidative phosphorylation. An increased dependence on glutamine utilization is exhibited to support TCA cycle substrates in this metabolic rewiring of BRAF mutated melanoma. Herein we describe the relevant core metabolic pathways modulated by BRAF inhibition. These adaptive pathways represent vulnerabilities that could be targeted to overcome resistance to BRAF inhibitors. This review evaluates current and future therapeutic strategies that target metabolic reprogramming in melanoma cells, particularly in response to BRAF inhibition., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Uveal melanoma (UM) is a rare yet lethal primary intraocular malignancy affecting adults. Analysis of data from The Cancer Genome Atlas (TCGA) database revealed that FGFR1 expression was increased in UM tumor tissues and was linked to aggressive behavior and a poor prognosis. This study assessed the anti-tumor effects of Erdafitinib, a selective pan-FGFR inhibitor, in both in vitro and in vivo UM models. Erdafitinib exhibited a robust anti-cancer activity in UM through inducing ferroptosis in the FGFR1-dependent manner. Transcriptomic data revealed that Erdafitinib mediated its anti-cancer effects via modulating the ferritinophagy/lysosome biogenesis. Subsequent research revealed that Erdafitinib exerted its effects by reducing the expression of FGFR1 and inhibiting the activity of mTORC1 in UM cells. Concurrently, it enhanced the dephosphorylation, nuclear translocation, and transcriptional activity of TFEB. The aggregation of TFEB in nucleus triggered FTH1-dependent ferritinophagy, leading to lysosomal activation and iron overload. Conversely, the overexpression of FGFR1 served to mitigate the effects of Erdafitinib on ferritinophagy, lysosome biogenesis, and the activation of the mTORC1/TFEB signaling pathway. In vivo experiments have convincingly shown that Erdafitinib markedly curtails tumor growth in an UM xenograft mouse model, an effect that is closely correlated with a decrease in FGFR1 expression levels. The present study is the first to demonstrate that Erdafitinib powerfully induces ferroptosis in UM by orchestrating the ferritinophagy and lysosome biogenesis via modulating the FGFR1/mTORC1/TFEB signaling. Consequently, Erdafitinib emerges as a strong candidate for clinical trial investigation, and FGFR1 emerges as a novel and promising therapeutic target in the treatment of UM., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Ocular melanoma, including uveal melanoma (UM) and conjunctival melanoma (CM), is the most common ocular cancer among adults with a high rate of recurrence and poor prognosis. Loss of epigenetic homeostasis disturbed gene expression patterns, resulting in oncogenesis. Herein, we comprehensively analyzed the DNA methylation, transcriptome profiles, and corresponding clinical information of UM patients through multiple machine-learning algorithms, finding that a methylation-driven gene RBMS1 was correlated with poor clinical outcomes of UM patients. RNA-seq and single-cell RNA-seq analyses revealed that RBMS1 reflected diverse tumor microenvironments, where high RBMS1 expression marked an immune active TME. Furthermore, we found that tumor cells were identified to have the higher communication probability in RBMS1 + state. The functional enrichment analysis revealed that RBMS1 was associated with pigment granule and melanosome, participating in cell proliferation as well as apoptotic signaling pathway. Biological experiments were performed and demonstrated that the silencing of RBMS1 inhibited ocular melanoma proliferation and promoted apoptosis. Our study highlighted that RBMS1 reflects a distinct microenvironment and promotes tumor progression in ocular melanoma, contributing to the therapeutic customization and clinical decision-making., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The melanoma tumor microenvironment is a complex milieu of cancer, inflammatory, and stromal cells. In this context, chemokines play a pivotal role in recruiting inflammatory cells and influence the tumor, exerting both pro-tumorigenic and anti-tumoral roles. Interactions between these cells is what ultimately hold together and transform the tumor into an efficient machine. A recent study found that chemokines CCL8, CCL15, and CCL20 were upregulated in melanoma cells when co-cultured with macrophages and were associated with poor survival rates. CCL8 and CCL15 also stimulated melanoma cell growth, invasion, and metastasis, and were highly expressed in tumors prone to metastasize, suggesting these chemokines are attractive and independent biomarkers. Understanding the intricated interactions within the tumor microenvironment could lead to prognostic biomarkers and to the development of new therapeutic strategies for melanoma. © 2024 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland., (© 2024 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.)

Canine tumours including urothelial carcinoma, lung adenocarcinoma, mammary gland tumour, squamous cell carcinoma, and melanoma have been identified as causes of death, but effective therapies are limited due to insufficient knowledge of the molecular mechanisms involved. Within the tumour microenvironment, hypoxia activates hypoxia-inducible factor 1α (HIF1α) in tumour cells. High HIF1α expression correlates with enhanced glycolysis and poorer outcomes in human cancers. However, the molecular mechanisms underlying hypoxic tumour cells remain elusive in dogs. In our study, we investigated upregulated genes in a canine malignant melanoma cell line during hypoxia using RNA-sequencing analysis. Glycolysis and HIF1 signalling pathways were upregulated in hypoxic melanoma cells. HIF1α knockout melanoma cells revealed that the glycolysis marker MCT4 is regulated by HIF1α activation. Hypoxia induces high lactate secretion due to enhanced glycolysis in canine melanoma cells. Furthermore, we examined monocarboxylate transporter 4 (MCT4) expression in malignant melanoma and eight other types of canine tumour tissues using immunohistochemistry (IHC). Membrane-localized MCT4 protein was mostly detected in urothelial carcinoma and lung adenocarcinoma rather than malignant melanoma. We conclude that canine MCT4 protein plays a role in lactic acid efflux from glycolytic cells and may serve as a marker for hypoxia and glycolysis in canine tumours. These findings could inform future therapeutic strategies targeting MCT4., (© 2024 John Wiley & Sons Ltd.)

Melanoma, with its diverse histopathologic characteristics, can mimic both benign nevi and neoplasms of various cell lineages. Immunohistochemistry (IHC) can play a vital role in melanoma diagnosis, particularly when the cell lineage is unclear on hematoxylin and eosin sections. Commonly utilized IHC stains for melanoma diagnosis include SOX10, Melan-A, and S100. A relatively novel stain, PReferentially expressed Antigen in MElanoma (PRAME), is also proving useful in accurate melanoma diagnosis. However, none of these stains are completely specific to melanocytes or melanoma, and misinterpretation can lead to incorrect diagnoses. This report presents a unique case of triple-negative breast carcinoma (TNBC) metastatic to the skin exhibiting histopathologic characteristics similar to melanoma, including positivity for SOX10 and PRAME. Our aim is to highlight TNBC metastatic to the skin as a potential diagnostic pitfall., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

In felines, ocular and nonocular melanomas are uncommon tumors that represent a diagnostic challenge for pathologists, especially when amelanotic. To date, the immunohistochemical diagnostic panel in cats is based on specific melanocytic markers (Melan-A and PNL2) and a nonspecific but sensitive marker (S100). In human medicine, SOX-10 is reported to be a sensitive antibody for the detection of melanoma micrometastasis in the lymph node. TRP-1, an enzyme involved in melanogenesis, has recently been used in humans and dogs as a specific melanocyte marker. The aim of this study was to evaluate the cross-reactivity and the expression of SOX-10 and TRP-1 antibodies in feline normal tissue and melanocytic tumors. Thirty-one cases of ocular, cutaneous, and oral melanomas were retrospectively evaluated and confirmed by histopathological examination and by immunolabeling with Melan-A and/or PNL2. SOX-10 nuclear expression in normal tissues was localized in epidermal, subepidermal, hair bulb, and iridal stromal melanocytes and dermal nerves. In melanomas, nuclear expression of SOX-10 was detected in ocular (11/12; 92%), oral (6/7; 86%), and cutaneous sites (12/12; 100%). TRP-1 cytoplasmic immunolabeling in normal tissue was observed in epidermal and bulbar melanocytes and in the lining pigmented epithelium of the iris and in its stroma. Its expression was positively correlated to the degree of pigmentation in the tumor and was observed in 75% of ocular (9/12), 43% of oral (3/7), and 33% of cutaneous melanomas (4/12). This study demonstrated the cross-reactivity of SOX-10 and TRP-1 antibodies in feline non-neoplastic melanocytes and their expression in ocular and nonocular melanomas., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Canine oral malignant melanoma (COMM) is the most common neoplasm in the oral cavity characterized by local invasiveness and high metastatic potential. Hypoxia represents a crucial feature of the solid tumor microenvironment promoting cancer progression and drug resistance. Hypoxia-inducible factor-1α (HIF-1α) and its downstream effectors, vascular endothelial growth factor A (VEGF-A), glucose transporter isoform 1 (GLUT1), C-X-C chemokine receptor type 4 (CXCR4), and carbonic anhydrase IX (CAIX), are the main regulators of the adaptive response to low oxygen availability. The prognostic value of these markers was evaluated in 36 COMMs using immunohistochemistry. In addition, the effects of cobalt chloride-mediated hypoxia were evaluated in 1 primary COMM cell line. HIF-1α expression was observed in the nucleus, and this localization correlated with the presence or enhanced expression of HIF-1α-regulated genes at the protein level. Multivariate analysis revealed that in dogs given chondroitin sulfate proteoglycan-4 ( CSPG4 ) DNA vaccine, COMMs expressing HIF-1α, VEGF-A, and CXCR4 were associated with shorter disease-free intervals (DFI) compared with tumors that were negative for these markers ( P = .03), suggesting hypoxia can influence immunotherapy response. Western blotting showed that, under chemically induced hypoxia, COMM cells accumulate HIF-1α and smaller amounts of CAIX. HIF-1α induction and stabilization triggered by hypoxia was corroborated by immunofluorescence, showing its nuclear translocation. These findings reinforce the role of an hypoxic microenvironment in tumor progression and patient outcome in COMM, as previously established in several human and canine cancers. In addition, hypoxic markers may represent promising prognostic markers, highlighting opportunities for their use in therapeutic strategies for COMMs., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Melanoma is the third most common malignant skin tumor and has increased in morbidity and mortality over the previous decade due to its rapid spread into the bloodstream or lymphatic system. This study used integrated bioinformatics and network-based methodologies to reliably identify molecular targets and small molecular medicines that may be more successful for Melanoma diagnosis, prognosis and treatment. The statistical LIMMA approach utilized for bioinformatics analysis in this study found 246 common differentially expressed genes (cDEGs) between case and control samples from two microarray gene-expression datasets (GSE130244 and GSE15605). Protein-protein interaction network study revealed 15 cDEGs (PTK2, STAT1, PNO1, CXCR4, WASL, FN1, RUNX2, SOCS3, ITGA4, GNG2, CDK6, BRAF, AGO2, GTF2H1 and AR) to be critical in the development of melanoma (KGs). According to regulatory network analysis, the most important transcriptional and post-transcriptional regulators of DEGs and hub-DEGs are ten transcription factors and three miRNAs. We discovered the pathogenetic mechanisms of MC by studying DEGs' biological processes, molecular function, cellular components and KEGG pathways. We used molecular docking and dynamics modeling to select the four most expressed genes responsible for melanoma malignancy to identify therapeutic candidates. Then, utilizing the Connectivity Map (CMap) database, we analyzed the top 4-hub-DEGs-guided repurposable drugs. We validated four melanoma cancer drugs (Fisetin, Epicatechin Gallate, 1237586-97-8 and PF 431396) using molecular dynamics simulation with their target proteins. As a result, the results of this study may provide resources to researchers and medical professionals for the wet-lab validation of MC diagnosis, prognosis and treatments.Communicated by Ramaswamy H. Sarma.

Melanoma poses a poor prognosis with high mortality rates upon metastasis. Exploring the molecular mechanisms governing melanoma progression paves the way for developing novel approaches to control melanoma metastasis and ultimately enhance patient survival rates. Extracellular galectin-3 (Gal-3) has emerged as a pleiotropic promoter of melanoma metastasis, exerting varying activities depending on its interacting partner. However, whether intracellular Gal-3 promotes melanoma aggressive behavior remains unknown. In this study, we explored Gal-3 expression in human melanoma tissues as well as in murine melanoma models to examine its causal role in metastatic behavior. We found that Gal-3 expression is downregulated in metastatic melanoma tissues compared with its levels in primary melanomas. Enforced silencing of Gal-3 in melanoma cells promoted migration, invasion, colony formation, in vivo xenograft growth, and metastasis and activated canonical oncogenic signaling pathways. Moreover, loss of Gal-3 in melanoma cells resulted in upregulated the expression of the prometastatic transcription factor NFAT1 and its downstream metastasis-associated proteins, matrix metalloproteinase 3, and IL-8. Overall, our findings implicate melanoma intracellular Gal-3 as a major determinant of its metastatic behavior and reveal a negative regulatory role for Gal-3 on the expression of NFAT1 in melanoma cells., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Aberrant glycosylation recently emerged as an unmissable hallmark of cancer progression in many cancers. In melanoma, there is growing evidence that the tumour 'glycocode' plays a major role in promoting cell proliferation, invasion, migration, but also dictates the nature of the immune infiltrate, which strongly affects immune cell function, and clinical outcome. Aberrant glycosylation patterns dismantle anti-tumour defence through interactions with lectins on immune cells, which are crucial to shape anti-tumour immunity but also to trigger immune evasion. The glycan/lectin axis represents a new immune subversion pathway that is exploited by melanoma to hijack immune cells and escape from immune control. In this review, we describe the glycosylation features of melanoma tumour cells, and further gather findings related to the role of glycosylation in melanoma tumour progression, deciphering in detail its impact on immunity. We also depict glycan-based strategies aiming at restoring a functional anti-tumour response in melanoma patients. Glycans/lectins emerge as key immune checkpoints with promising translational properties. Exploitation of these pathways could reshape potent anti-tumour immunity while impeding immunosuppressive circuits triggered by aberrant tumour glycosylation patterns, holding great promise for cancer therapy., (© 2024 The Authors. Immunology published by John Wiley & Sons Ltd.)

Melanoma, arising from the malignant transformation of melanocytes, stands as the most lethal type of skin cancer. While significant strides have been made in targeted therapy and immunotherapy, substantially enhancing therapeutic efficacy, the prognosis for melanoma patients remains unoptimistic. SIRT7, a nuclear-localized deacetylase, plays a pivotal role in maintaining cellular homeostasis and adapting to external stressors in melanoma, with its activity closely tied to intracellular nicotinamide adenine dinucleotide (NAD + ). However, its involvement in adaptive resistance to targeted therapy remains unclear. Herein, we unveil that up-regulated SIRT7 promotes mitochondrial biogenesis to render the adaptive resistance to MAPK inhibition in melanoma. Initially, we observed a significant increase of SIRT7 expression in publicly available datasets following targeted therapy within a short duration. In consistent, we found elevated SIRT7 expression in melanoma cells subjected to BRAF or MEK inhibitors in vitro. The up-regulation of SIRT7 expression was also confirmed in xenograft tumors in mice after targeted therapy in vivo. Furthermore, we proved that SIRT7 deficiency led to decreased cell viability upon prolonged exposure to BRAF or MEK inhibitors, accompanied by an increase in cell apoptosis. Mechanistically, SIRT7 deficiency restrained the upregulation of genes associated with mitochondrial biogenesis and intracellular ATP levels in response to targeted therapy treatment in melanoma cells. Ultimately, we proved that SIRT7 deficieny could sensitize BRAF-mutant melanoma cells to MAPK inhibition targeted therapy in vivo. In conclusion, our findings underscore the role of SIRT7 in fostering adaptive resistance to targeted therapy through the facilitation of mitochondrial biogenesis. Targeting SIRT7 emerges as a promising strategy to overcome MAPK inhibitor adaptive resistance in melanoma., Competing Interests: Declaration of competing interest The authors have declared no conflict of interest., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The dynamic regulation of mitochondria shape via fission and fusion is critical for cellular responses to stimuli. In homeostatic cells, two modes of mitochondrial fission, midzone and peripheral, provide a decision fork between either proliferation or clearance of mitochondria. However, the relationship between specific mitochondria shapes and functions remains unclear in many biological contexts. While commonly associated with decreased bioenergetics, fragmented mitochondria paradoxically exhibit elevated respiration in several disease states, including infection with the prevalent pathogen human cytomegalovirus (HCMV) and metastatic melanoma. Here, incorporating super-resolution microscopy with mass spectrometry and metabolic assays, we use HCMV infection to establish a molecular mechanism for maintaining respiration within a fragmented mitochondria population. We establish that HCMV induces fragmentation through peripheral mitochondrial fission coupled with suppression of mitochondria fusion. Unlike uninfected cells, the progeny of peripheral fission enter mitochondria-ER encapsulations (MENCs) where they are protected from degradation and bioenergetically stabilized during infection. MENCs also stabilize pro-viral inter-mitochondria contacts (IMCs), which electrochemically link mitochondria and promote respiration. Demonstrating a broader relevance, we show that the fragmented mitochondria within metastatic melanoma cells also form MENCs. Our findings establish a mechanism where mitochondria fragmentation can promote increased respiration, a feature relevant in the context of human diseases., (© 2024. The Author(s).)

Programmed cell death 1 (PD-1) is a premier cancer drug target for immune checkpoint blockade (ICB). Because PD-1 receptor inhibition activates tumor-specific T-cell immunity, research has predominantly focused on T-cell-PD-1 expression and its immunobiology. In contrast, cancer cell-intrinsic PD-1 functional regulation is not well understood. Here, we demonstrate induction of PD-1 in melanoma cells via type I interferon receptor (IFNAR) signaling and reversal of ICB efficacy through IFNAR pathway inhibition. Treatment of melanoma cells with IFN-α or IFN-β triggers IFNAR-mediated Janus kinase-signal transducer and activator of transcription (JAK/STAT) signaling, increases chromatin accessibility and resultant STAT1/2 and IFN regulatory factor 9 (IRF9) binding within a PD-1 gene enhancer, and leads to PD-1 induction. IFNAR1 or JAK/STAT inhibition suppresses melanoma-PD-1 expression and disrupts ICB efficacy in preclinical models. Our results uncover type I IFN-dependent regulation of cancer cell-PD-1 and provide mechanistic insight into the potential unintended ICB-neutralizing effects of widely used IFNAR1 and JAK inhibitors., (© 2024. The Author(s).)

Background: BRAF (v-raf murine sarcoma viral oncogene homolog B1)/MEK (mitogen-activated protein kinase kinase) inhibitors are used for melanoma treatment. Unfortunately, patients treated with this combined therapy develop resistance to treatment quite quickly, but the mechanisms underlying this phenomenon are not yet fully understood. Here, we report and characterize two melanoma cell lines (WM9 and Hs294T) resistant to BRAF (vemurafenib) and MEK (cobimetinib) inhibitors., Methods: Cell viability was assessed via the XTT test. The level of selected proteins as well as activation of signaling pathways were evaluated using Western blotting. The expression of the chosen genes was assessed by RT-PCR. The distribution of cell cycle phases was analyzed by flow cytometry, and confocal microscopy was used to take photos of spheroids. The composition of cytokines secreted by cells was determined using a human cytokine array., Results: The resistant cells had increased survival and activation of ERK kinase in the presence of BRAF/MEK inhibitors. The IC 50 values for these cells were over 1000 times higher than for controls. Resistant cells also exhibited elevated activation of AKT, p38, and JNK signaling pathways with increased expression of EGFR, ErbB2, MET, and PDGFRβ receptors as well as reduced expression of ErbB3 receptor. Furthermore, these cells demonstrated increased expression of genes encoding proteins involved in drug transport and metabolism. Resistant cells also exhibited features of epithelial-mesenchymal transition and cancer stem cells as well as reduced proliferation rate and elevated cytokine secretion., Conclusions: In summary, this work describes BRAF/MEK-inhibitor-resistant melanoma cells, allowing for better understanding the underlying mechanisms of resistance. The results may thus contribute to the development of new, more effective therapeutic strategies., (© 2024. The Author(s).)

We report a successful formulation of Artemisone (ATM) in transferrin (Tf)-conjugated nanostructured lipid carriers (NLCs), achieving nearly a five-times increase in cell toxicity. The escalating cost of new drug discoveries led to the repurposing of approved drugs for new indications. This study incorporated Artemisone, an antimalarial drug, into a nanostructured lipid carrier (NLC) and tested for possible anticancer effects. The aim was to develop NLCs, and transferrin-conjugated NLCs (NLC-Tf) encapsulating Artemisone to enhance its delivery and anticancer activity. NLC formulations were prepared using high-pressure homogenization followed by ultrasonication and were characterized by particle size, zeta potential, and PDI. The conjugation of (Tf) to (NLC) was confirmed using IR, and the anticancer activity was tested using MTS assay. All formulations were in the nanometer size range (140-167 nm) with different zeta potential values. IR spectroscopy confirmed the successful conjugation of transferrin to NLC. Upon testing the formulations on melanoma cell lines using MTS assay, there was a significant decrease in viability and an increase in the encapsulated ATM-Tf toxicity compared to positive control ATM. The NLCs presented a promising potential carrier for delivering ATM to melanoma cells, and further conjugation with Tf significantly improved the ATM cytotoxicity.

There is a critical need to non-invasively assess the PD-L1 expression in tumors as a predictive biomarker for determining the efficacy of anti-PD-1/PD-L1 immunotherapies. Non-invasive imaging modality like positron emission tomography (PET) can be a powerful tool to assess the PD-L1 expression in the whole body including multiple metastases as a patient selection criterion for the anti-PD-1/PD-L1 immunotherapy. In this study, we synthesized B11-nanobody, B11-scFv and B11-diabody fragments from the full-length anti-PD-L1 B11 IgG. Out of the three antibody fragments, B11-diabody showed higher nM affinity towards PD-L1 antigen as compared to B11-scFv and B11-nanobody. All three antibody fragments were successfully radiolabeled with 64 Cu, a PET radioisotope. For radiolabeling, the antibody fragments were first conjugated with p-SCN-Bn-NOTA followed by chelation with 64 Cu. All three radiolabeled antibody fragments were found to be stable in mouse and human sera for up to 24 h. Additionally, all three [ 64 Cu]Cu-NOTA-B11-antibody fragments were evaluated in PD-L1 negative and human PD-L1 expressing cancer cells and subcutaneous tumor models. Based on the results, [ 64 Cu]Cu-NOTA-B11-diabody has potential to be used as a PET imaging probe for assessing PD-L1 expression in tumors as early as 4 h post-injection, allowing faster assessment compared to the full length IgG based PET imaging probe., (© 2024. The Author(s).)

Background: Melanoma, one of the most lethal forms of skin cancer, has the potential to develop in any area where melanocytes are present. Currently, postoperative recurrence due to the emergence of systemic drug resistance represents a significant challenge in the treatment of melanoma. In this study, terphenyllin (TER), a distinctive inhibitory impact on melanoma cells was identified from the natural p-terphenyl metabolite. This study aimed to elucidate the intrinsic mechanism of this inhibitory effect, which may facilitate the discovery of novel chemotherapeutic agents., Methods: A transcriptome sequencing and metabolomic analysis of TER-treated A375 cells was conducted to identify potential pathways of action. The key proteins were knocked out and backfilled using CRISPR-Cas9 technology and molecular cloning. Subsequently, the results of cytosolic viability, LDH release, immunofluorescence and flow cytometry were employed to demonstrate the cell death status of the drug-treated cells., Results: The p53 signalling pathway was markedly upregulated following TER treatment, leading to the activation of CASP3 via the intrinsic apoptotic pathway. The activated CASP3 initiated apoptosis, while simultaneously continuing to cleave the GSDME, thereby triggering pyroptosis. The knockout of p53, a key protein situated upstream of this pathway, resulted in a significant rescue of TER-induced cell death, as well as an alleviation of the decrease in cell viability. However, the knockout of key proteins situated downstream of the pathway (CASP3 and GSDME) did not result in a rescue of TER-induced cell death, but rather a transformation of the cells from apoptosis and pyroptosis., Conclusions: The induction of apoptosis and pyroptosis in A375 cells by TER is mediated via the p53-BAX/FAS-CASP3-GSDME signalling pathway. This lays the foundation for TER as a potential anti-melanoma drug in the future. It should be noted that CASP3 and GSDME in this pathway solely regulate the mode of cell death, rather than determine whether cell death occurs. This distinction may prove valuable in future studies of apoptosis and pyroptosis., (© 2024. The Author(s).)

Background: Melanoma is a highly aggressive form of skin cancer. The existence of cancer stem cells (CSCs) and tumor immune evasion are two major causes of melanoma progression, but no effective treatment has been found at present. Astragalus polysaccharide (APS) is a principal active component derived from Astragalus membranaceus, showing anti-tumor effects in various tumors including melanoma. However, the underlying mechanism is still unclear., Methods: The regulation of APS on self-renewal ability and CSC markers expression in melanoma stem cells (MSCs) was measured by tumor sphere formation and tumorigenicity assays, RT-qPCR, and western blot. Flow cytometry was conducted to evaluate the activation of immune system by APS in melanoma mice. Further, the mechanism was explored based on PD-L1 overexpression and knock-down B16 cells., Results: APS attenuated the tumor sphere formation of MSCs in vitro as well as the tumorigenicity in vivo. It also decreased the expression of CD133, BMI1 and CD47. Based on the PD-L1 overexpression and knock-down B16 cells, it was confirmed that APS inhibited the induction of MSCs by down-regulating PD-L1 expression. Meanwhile, APS increased the infiltration of CD4 + and CD8 + T cells in tumor tissues because of its inhibitory effect on PD-L1., Conclusions: APS inhibited MSC induction and overcame tumor immune evasion through reducing PD-L1 expression. This study provided compelling evidence that APS could be a prospective therapeutic agent for treating melanoma., (© 2024. The Author(s).)

Melanoma, the deadliest skin cancer, originates from epidermal melanocytes. The influence of preadipocytes on melanoma is less understood. We co-cultured mouse melanoma B16 cells with 3T3L1 preadipocytes to form mixed spheroids and observed increased melanoma proliferation and growth compared to B16-only spheroids. Metastasis-related proteins YAP, TAZ, and PD-L1 levels were also higher in mixed spheroids. Treatment with exosome inhibitor GW4869 halted melanoma growth and reduced expression of these proteins, suggesting exosomal crosstalk between B16 and 3T3L1 cells. MiR-155 expression was significantly higher in mixed spheroids, and GW4869 reduced its levels. Additionally, co-culturing with Raw264.7 macrophage cells increased M2 markers IL-4 and CD206 in Raw264.7 cells, effects that were diminished by GW4869. These results indicate that preadipocytes may enhance melanoma progression and metastasis via exosomal interactions., Competing Interests: Declaration of competing interest The authors declare that they have no competing financial interests or personal relationships that may have influenced the work reported in this study., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Metastatic melanoma stands out as the most lethal form of skin cancer because of its high propensity to spread and its remarkable resistance to treatment methods., Methods: In this review article, we address the incidence of melanoma worldwide and its staging phases. We thoroughly investigate the different melanomas and their associated risk factors. In addition, we underscore the principal therapeutic goals and pharmacological methods that are currently used in the treatment of melanoma., Results: The implementation of targeted therapies has contributed to improving the approach to patients. However, because of the emergence of resistance early in treatment, overall survival and progression-free periods continue to be limited., Conclusions: We provide new insights into plant serine protease inhibitor therapeutics, supporting high-throughput drug screening soon, and seeking a complementary approach to explain crucial mechanisms associated with melanoma.

Uveal melanoma (UM) is the most common primary intraocular tumor in adults, with no standardized treatment for advanced disease. Based on preliminary bioinformatical analyses DTYMK and PARP1 were selected as potential therapeutic targets. High levels of both proteins were detected in uveal melanoma cells and correlated with increased tumor growth and poor prognosis. In vitro tests on MP41 (BAP1 positive) and MP46 (BAP1 negative) cancer cell lines using inhibitors pamiparib (PARP1) and Ymu1 (DTYMK) demonstrated significant cytotoxic effects. Combined treatment had synergistic effects in MP41 and additive in MP46 cell lines, reducing cell proliferation and inhibiting the mTOR signaling pathway. Furthermore, the applied inhibitors in combination decreased cell motility and migration speed, especially for BAP1-negative cell lines. Our hypothesis of the double hit into tumoral DNA metabolism as a possible therapeutic option in uveal melanoma was confirmed since combined targeting of DTYMK and PARP1 affected all tested cytophysiological parameters with the highest efficiency. Our in vitro findings provide insights into novel therapeutic avenues for managing uveal melanoma, warranting further exploration in preclinical and clinical settings.

Keratinocytes are major cellular components of the skin and are strongly involved in its homeostasis. Oncogenic events, starting mainly from excessive sun exposure, lead to the dysregulation of their proliferation and differentiation programs and promote the initiation and progression of non-melanoma skin cancers (NMSCs). Primary melanomas, which originate from melanocytes, initiate and develop in close interaction with keratinocytes, whose role in melanoma initiation, progression, and immune escape is currently being explored. Recent studies highlighted, in particular, unexpected modes of communication between melanocytic cells and keratinocytes, which may be of interest as sources of new biomarkers in melanomagenesis or potential therapeutic targets. This review aims at reporting the various contributions of keratinocytes in skin basal cell carcinoma (BCC), cutaneous squamous cell carcinoma (cSCC), and melanoma, with a greater focus on the latter in order to highlight some recent breakthrough findings. The readers are referred to recent reviews when contextual information is needed.

Ectosomes are carriers of proangiogenic factors during cancer progression. This study investigated whether the proangiogenic effect exerted by melanoma-derived ectosomes on recipient endothelial cells is mediated by ectosomal αvβ3 and αvβ5 integrins. Ectosomes were isolated from the conditioned culture media of four melanoma cell lines and melanocytes. Changes in gene and protein expression of αvβ3 and αvβ5 integrins, as well as VEGF and TNF-α were assessed in ectosome-treated endothelial cells. To confirm the functional involvement of ectosomal integrins in functional tests (Alamar Blue, wound healing and tube formation assays), ectosomes were also pretreated with anti-integrin antibodies and integrin-blocking peptides echistatin and cilengitide. Melanoma-derived ectosomes induced changes in the expression of αvβ3 and αvβ5 integrins in recipient endothelial cells, leading to increased viability, migratory properties, and tube formation potential. The extent of proangiogenic stimulation varied depending on the types of cells releasing ectosomes and the recipient cells. The use of anti-integrin antibodies and integrin-blocking peptides revealed a more significant role for the αvβ5 integrin/VEGF than the αvβ3 integrin/TNF-α pathway in the interactions between ectosomes and endothelial cells. The study demonstrated the functional role of ectosomal αvβ3 and αvβ5 integrins. It also provided a baseline understanding of ectosome-mediated αvβ3 integrin/TNF-α and αvβ5 integrin/VEGF signaling in angiogenesis.

Melatonin, noted for its anti-cancer properties in various malignancies, including cutaneous melanoma, shows promise in Uveal melanoma (UM) treatment. This study aimed to evaluate melatonin receptor expression in primary UM and its association with UM-related mortality and prognostic factors. Immunohistochemical analysis of 47 primary UM tissues showed low expression of melatonin receptor 1A (MTNR1A) and melatonin receptor 1B (MTNR1B), with MTNR1A significantly higher in patients who succumbed to UM. Analysis of TCGA data from 80 UM patients revealed RNA expression for MTNR1A, retinoic acid-related orphan receptor alpha (RORα), and N-ribosyldihydronicotinamide:quinone oxidoreductase (NQO2), but not MTNR1B or G protein-coupled receptor 50 (GPR50). Higher MTNR1A RNA levels were observed in patients with a BRCA1 Associated Protein 1 (BAP1) mutation, and higher NQO2 RNA levels were noted in patients with the epithelioid tumor cell type. However, Kaplan-Meier analysis did not show distinct survival probabilities based on receptor expression. This study concludes that UM clinical samples express melatonin receptors, suggesting a potential mechanism for melatonin's anti-cancer effects. Despite finding higher MTNR1A expression in patients who died of UM, no survival differences were observed.

Objective: To investigate the clinicopathological, immunohistochemical and molecular characteristics of cutaneous ALK-rearranged Spitz melanocytoma. Methods: Two cases of cutaneous ALK-rearranged Spitz melanocytoma from outside hospital consultations in Department of Pathology, Affiliated Cancer Hospital of Fudan University in August 2020 and in Shanghai Ackermann Medical Laboratory in June 2022 were collected. The clinicopathological features, immunophenotypes and molecular profiles of two patients with cutaneous Spitzoid melanocytic tumor harboring ALK-rearrangement were analyzed. The literatures were reviewed. Results: The study included an 8-year-old boy and an 11-year-old girl, who presented with a polypoid lesion in the skin of right thigh and left auricle measuring 1.0 cm and 1.2 cm, respectively. Histologically, they were composed of medium to large-sized epithelioid to plump spindle cells, arranged in nested, plexiform or fascicular patterns in the superficial dermis. The neoplastic cells had abundant eosinophilic cytoplasm with round to ovoid vesicular nuclei containing prominent eosinophilic nucleoli. One case showed mild to moderate nuclear pleomorphism and mitotic activity (average, 2/mm 2 ). Immunohistochemically, the epithelioid and plump spindle cells showed diffuse and strong staining of S-100 protein, SOX10, and ALK (D5F3 and 1A4), but did not express HMB45, PNL2 and MiTF. ALK-rearrangement was detected by fuorescence in situ hybridization in both cases. Subsequent next generation sequence (NGS) analysis identified KANK1::ALK and TPM3:ALK fusions. At 34 and 14 months after surgical resection, both patients remained well with no signs of recurrence or metastasis. Conclusions: ALK-rearranged Spitz melanocytoma represents a morphologically and genetically distinct subset of Spitz melanocytoma, characterized clinically by predilection in children and adolescents, with Spitzoid morphology in plexiform pattern, positive immunohistochemical stains, and rearrangement of ALK. As some cases show atypical features and high mitotic activity, a distinction from Spitz melanoma is warranted.

Objective: To investigate the clinical, cytomorphology, immunocytochemical and molecular features of metastatic melanoma in serosal cavity effusion. Methods: Cytological specimens of 14 patients with melanoma in the chest and abdomen were collected from 2017 to 2023, at the Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China. SOX10, S-100 protein, PRAME, BRAF V600E, HMB45, and Melan A were detected by immunocytochemical methods. Fourteen cases were tested for routine antibody combinations, including Claudin4, HEG1, Calretinin, CD68, etc. Four of the patients had biopsy or surgical samples of metastatic solid lesions of primary sites, and further next-generation sequencing (NGS) or amplification refractory mutation system (ARMS)-PCR molecular test was performed. In addition, 30 cases of serosal effusion samples were collected as control groups (10 cases of benign mesothelial cell reactive hyperplasia, 10 cases of mesothelioma, and 10 cases of metastatic lung adenocarcinoma). Results: Among the 14 cases of melanoma, there were 7 males and 7 females, with ages ranging from 35 to 86 years, and an average age of 57 years, there 10 cases aged ≥50 years. The tumor cells in the serosal effusion varied in morphology and degree of atypia. SOX10 was positive in all 14 cases (14/14), S-100 protein was positive in 10 cases (10/14), PRAME was positive in 12 cases (12/14), BRAF V600E was positive in 10 cases (10/14), HMB45 was positive in 12 cases (12/14), and Melan A was positive in 13 cases (13/14). In 4 patients with histological correlation, the cytological and histological expression of SOX10, BRAF V600E, and PRAME was positive in all 4 cases (4/4); S-100 protein was positive in 2 cases (2/4); and HMB45 and Melan A were positive in 3 cases (3/4). Using NGS or ARMS-PCR, missense mutations of BRAF V600E were detected in all 4 patients; TERT promoter mutations was detected in 1 case; and CDKN2A terminating mutations and MSI1 deletion mutations were detected in the other case. SOX10, S-100, HMB45, Melan A, PRAME and BRAF V600E were all negative in 30 control samples of serosal cavity effusion. Conclusion: By observing the morphology of tumor cells, immunocytochemical test of several combination markers, especially the expression of SOX10, BRAF V600E and PRAME, can help to improve the positive diagnosis rate of melanoma in serous cavity effusion.

Photothermal therapy (PTT) has emerged as a noninvasive and precise cancer treatment modality known for its high selectivity and lack of drug resistance. However, the clinical translation of many PTT agents is hindered by the limited biodegradability of inorganic nanoparticles and the instability of organic dyes. In this study, a peptide conjugate, IR820-Cys-Trp-Glu-Trp-Thr-Trp-Tyr ( IR820-C ), was designed to self-assemble into nanoparticles for both potent PTT and vascular disruption in melanoma treatment. When co-assembled with the poorly soluble vascular disrupting agent (VDA) combretastatin A4 (CA4), the resulting nanoparticles ( IR820-C@CA4 NPs ) accumulate efficiently in tumors, activate systemic antitumor immune responses, and effectively ablate melanoma with a single treatment and near-infrared irradiation, as confirmed by our in vivo experiments. Furthermore, by exploiting the resulting tumor hypoxia, we subsequently administered the hypoxia-activated prodrug tirapazamine (TPZ) to capitalize on the created microenvironment, thereby boosting therapeutic efficacy and antimetastatic potential. This study showcases the potential of short-peptide-based nanocarriers for the design and development of stable and efficient photothermal platforms. The multifaceted therapeutic strategy, which merges photothermal ablation with vascular disruption and hypoxia-activated chemotherapy, holds great promise for advancing the efficacy and scope of cancer treatment modalities.

Cytoglobin (CYGB) is a member of the oxygen-binding globin superfamily. In this study we generated stable CYGB overexpressing A375 melanoma cells and performed RNA-sequencing to comprehensively explore the CYGB-dependent transcriptome. Our findings reveal that ectopic expression of CYGB dysregulated multiple cancer-associated genes, including the mTORC1 and AKT/mTOR signaling pathways, which are frequently overactivated in tumors. Moreover, several cancer-associated pathways, such as epithelial-mesenchymal transition (EMT) mediated by CSPG4, were downregulated upon CYGB overexpression. Intriguingly, ectopic expression suggested anti-inflammatory potential of CYGB, as exemplified by downregulation of key inflammasome-associated genes, including NLRP1, CASP1 and CD74, which play pivotal roles in cytokine regulation and inflammasome activation. Consistent with established globin functions, CYGB appears to be involved in redox homeostasis. Furthermore, our study indicates CYGB's association to DNA repair mechanisms and its regulation of NOX4, reinforcing its functional versatility. Additionally, multiple significantly enriched pathways in CYGB overexpressing cells were consistently dysregulated in opposite direction in CYGB depleted cells. Collectively, our RNA-sequencing based investigations illustrate the diverse functions of CYGB in melanoma cells, pointing to its putative roles in cellular protection against oxidative stress, inflammation, and cancer-associated pathways. These findings pave the way for further research into the physiological role of CYGB and its potential as a candidate therapeutic target in melanoma., (© 2024. The Author(s).)

Drugs or cellular products that bind to gp100 are being investigated for treatment of cutaneous melanoma. The relative specificity of gp100 expression in melanocytes makes it an attractive target to harness for therapeutic intent. For example, Tebentafusp, a bispecific gp100 peptide-HLA-directed CD3 T cell engager, has generated significant enthusiasm in recent years due to its success in improving outcomes for uveal melanoma and is being studied in cutaneous melanoma. However, the extent and intensity of gp100 expression in advanced cutaneous melanoma has not been well studied. Here, we interrogated a large cohort of primary and metastatic melanomas for gp100 expression by immunohistochemistry. Expression in metastatic samples was globally higher and almost uniformly positive, however the degree of intensity was variable. Using a quantitative immunofluorescence method, we confirmed the variability in expression. As gp100-binding drugs are assessed in clinical trials, the association between activity of the drugs and the level of gp100 expression should be studied in order to potentially improve patient selection., (© 2024. The Author(s).)

Overexpression of the secretory protein renalase-1 negatively impacts the survival of melanoma and pancreatic cancer patients, while inhibition of renalase-1 signaling drives tumor rejection by promoting T-cell activation. Thus, we investigated the chemical complementarity between melanoma-resident, T-cell receptor (TCR) complementarity-determining region 3 (CDR3) amino acid sequences (AAs) and the renalase-1 protein. Increasing complementarity of TCR CDR3s to renalase-1 AAs, as assessed by a chemical complementarity scoring algorithm, was associated with improved overall survival (OS) in melanoma patients. The expression levels of several immune signature genes were significantly, positively correlated with increasing TCR CDR3-renalase-1 complementarity scores. Additionally, the survival association observed with high complementarity of TCR CDR3s to renalase-1 AAs was more robust in cases with low renalase-1 gene expression levels. Mapping of TCR CDR3-renalase-1 in silico interaction sites identified major epitope candidates including RP220, the signaling module of the renalase-1 protein, consistent with the fact that a monoclonal antibody to RP220 is a potent inhibitor of melanoma growth. These findings indicate that renalase-1 is a potential antigen for TCR recognition in melanoma and could be considered as a target for immunotherapy.

The purpose of this study was to examine how the introduction of ibuprofen (IBU) affected tumor-targeting and biodistribution properties of 177 Lu-labeled IBU-conjugated alpha-melanocyte-stimulating hormone peptides. The IBU was used as an albumin binder and conjugated to the DOTA-Lys moiety without or with a linker to yield DOTA-Lys(IBU)-GG-Nle-CycMSH hex {1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid-Lys(IBU)-Gly-Gly-Nle-c[Asp-His-DPhe-Arg-Trp-Lys]-CONH 2 }, DOTA-Lys(Asp-IBU)-GGNle-CycMSH hex , DOTA-Lys(Asn-IBU)-GGNle-CycMSH hex , and DOTA-Lys(Dab-IBU)-GGNle-CycMSH hex peptides. Their melanocortin-receptor 1 (MC1R) binding affinities were determined on B16/F10 melanoma cells first. Then the biodistribution of 177 Lu-labeled peptides was determined on B16/F10 melanoma-bearing C57 mice at 2 h postinjection to choose the lead peptide for further examination. The full biodistribution and melanoma imaging properties of 177 Lu-DOTA-Lys(Asp-IBU)-GGNle-CycMSH hex were further evaluated using B16/F10 melanoma-bearing C57 mice. DOTA-Lys(IBU)-GG-Nle-CycMSH hex , DOTA-Lys(Asp-IBU)-GGNle-CycMSH hex , DOTA-Lys(Asn-IBU)-GGNle-CycMSH hex , and DOTA-Lys(Dab-IBU)-GGNle-CycMSH hex displayed the IC 50 values of 1.41 ± 0.37, 1.52 ± 0.08, 0.03 ± 0.01, and 0.58 ± 0.06 nM on B16/F10 melanoma cells, respectively. 177 Lu-DOTA-Lys(Asp-IBU)-GGNle-CycMSH hex exhibited the lowest liver and kidney uptake among all four designed 177 Lu peptides. Therefore, 177 Lu-DOTA-Lys(Asp-IBU)-GGNle-CycMSH hex was further evaluated for its full biodistribution and melanoma imaging properties. The B16/F10 melanoma uptake of 177 Lu-DOTA-Lys(Asp-IBU)-GGNle-CycMSH hex was 19.5 ± 3.12, 24.12 ± 3.35, 23.85 ± 2.08, and 10.80 ± 2.89% ID/g at 0.5, 2, 4, and 24 h postinjection, respectively. Moreover, 177 Lu-DOTA-Lys(Asp-IBU)-GGNle-CycMSH hex could clearly visualize the B16/F10 melanoma lesions at 2 h postinjection. The conjugation of IBU with or without a linker to GGNle-CycMSH hex affected the MC1R binding affinities of the designed peptides. The charge of the linker played a key role in the liver and kidney uptake of 177 Lu-Asp-IBU, 177 Lu-Asn-IBU, and 177 Lu-Dab-IBU. 177 Lu-Asp-IBU exhibited higher tumor/liver and tumor/kidney uptake ratios than those of 177 Lu-Asn-IBU and 177 Lu-Dab-IBU, underscoring its potential evaluation for melanoma therapy in the future.

Tumour-host immune interactions lead to complex changes in the tumour microenvironment (TME), impacting progression, metastasis and response to therapy. While it is clear that cancer cells can have the capacity to alter immune landscapes, our understanding of this process is incomplete. Herein we show that endocytic trafficking at the plasma membrane, mediated by the small GTPase ARF6, enables melanoma cells to impose an immunosuppressive TME that accelerates tumour development. This ARF6-dependent TME is vulnerable to immune checkpoint blockade therapy (ICB) but in murine melanoma, loss of Arf6 causes resistance to ICB. Likewise, downregulation of ARF6 in patient tumours correlates with inferior overall survival after ICB. Mechanistically, these phenotypes are at least partially explained by ARF6-dependent recycling, which controls plasma membrane density of the interferon-gamma receptor. Collectively, our findings reveal the importance of endomembrane trafficking in outfitting tumour cells with the ability to shape their immune microenvironment and respond to immunotherapy., (© 2024. The Author(s).)

Melanin is a crucial pigment in melanomagenesis. Its fluorescence in human tissue is exceedingly weak but can be detected through advanced laser spectroscopy techniques. The spectral profile of melanin fluorescence distinctively varies among melanocytes, nevomelanocytes, and melanoma cells, with melanoma cells exhibiting a notably "red" fluorescence spectrum. This characteristic enables the diagnosis of melanoma both in vivo and in histological samples. Neuromelanin, a brain pigment akin to melanin, shares similar fluorescence properties. Its fluorescence can also be quantified with high spectral resolution using the same laser spectroscopic methods. Documented fluorescence spectra of neuromelanin in histological samples from the substantia nigra substantiate these findings. Our research reveals that the spectral behavior of neuromelanin fluorescence mirrors that of melanin in melanomas. This indicates that the typical red fluorescence is likely influenced by the microenvironment around (neuro)melanin, rather than by direct pigment interactions. Our ongoing studies aim to further explore this distinctive "red" fluorescence. We have observed this red fluorescence spectrum in post-mortem measurements of melanin in benign nevus. The characteristic red spectrum is also evident here (unlike the benign nevus in vivo), suggesting that hypoxia may contribute to this phenomenon. Given the central role of hypoxia in both melanoma development and treatment, as well as in fundamental Parkinson's disease mechanisms, this study discusses strategies aimed at reinforcing the hypothesis that red fluorescence from (neuro)melanin serves as an indicator of hypoxia.

Background: Melanoma progression is based on a close interaction between cancer cells and immune cells in the tumor microenvironment (TME). Thus, a better understanding of the mechanisms controlling TME dynamics and composition will help improve the management of this dismal disease. Work from our and other groups has reported the requirement of an active Hedgehog-GLI (HH-GLI) signaling for melanoma growth and stemness. However, the role of the downstream GLI1 transcription factor in melanoma TME remains largely unexplored., Methods: The immune-modulatory activity of GLI1 was evaluated in a syngeneic B16F10 melanoma mouse model assessing immune populations by flow cytometry. Murine polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) were differentiated from bone marrow cells and their immunosuppressive ability was assessed by inhibition of T cells. Conditioned media (CM) from GLI1-overexpressing mouse melanoma cells was used to culture PMN-MDSCs, and the effects of CM were evaluated by Transwell invasion assay and T cell inhibition. Cytokine array analysis, qPCR and chromatin immunoprecipitation were performed to explore the regulation of CX3CL1 expression by GLI1. Human monocyte-derived dendritic cells (moDCs) were cultured in CM from GLI1-silenced patient-derived melanoma cells to assess their activation and recruitment. Blocking antibodies anti-CX3CL1, anti-CCL7 and anti-CXCL8 were used for in vitro functional assays., Results: Melanoma cell-intrinsic activation of GLI1 promotes changes in the infiltration of immune cells, leading to accumulation of immunosuppressive PMN-MDSCs and regulatory T cells, and to decreased infiltration of dendric cells (DCs), CD8 + and CD4 + T cells in the TME. In addition, we show that ectopic expression of GLI1 in melanoma cells enables PMN-MDSC expansion and recruitment, and increases their ability to inhibit T cells. The chemokine CX3CL1, a direct transcriptional target of GLI1, contributes to PMN-MDSC expansion and recruitment. Finally, silencing of GLI1 in patient-derived melanoma cells promotes the activation of human monocyte-derived dendritic cells (moDCs), increasing cytoskeleton remodeling and invasion ability. This phenotype is partially prevented by blocking the chemokine CCL7, but not CXCL8., Conclusion: Our findings highlight the relevance of tumor-derived GLI1 in promoting an immune-suppressive TME, which allows melanoma cells to evade the immune system, and pave the way for the design of new combination treatments targeting GLI1., (© 2024. The Author(s).)

Eleutherococcus divaricatus (Siebold and Zucc.) S. Y. Hu. has been used in Traditional Chinese Medicine (TCM) due to its anticancer, immunostimulant, and anti-inflammatory activities. However, its mechanism of action and chemical composition are still insufficiently understood and require more advanced research, especially for cases in which anti-inflammatory properties are beneficial. The aim of this study was to evaluate the impact of E. divaricatus root extracts and fractions on proinflammatory serum hyaluronidase and tyrosinase in children diagnosed with acute lymphoblastic leukemia. Antioxidant and anti-melanoma activities were also examined and correlated with metabolomic data. For the first time, we discovered that the ethyl acetate fraction significantly inhibits hyaluronidase activity, with mean group values of 55.82% and 63.8% for aescin used as a control. However, interestingly, the fraction showed no activity against human tyrosinase, and in A375 melanoma cells treated with a doxorubicin fraction, doxorubicin activity decreased. This fraction exhibited the most potent antioxidant activity, which can be attributed to high contents of polyphenols, especially caffeic acid (24 mg/g). The findings suggest an important role of the ethyl acetate fraction in hyaluronidase inhibition, which may additionally indicate its anti-inflammatory property. The results suggest that this fraction can be used in inflammatory-related diseases, although with precautions in cases of patients undergoing chemotherapy.

Melanocytes evolved to produce the melanin that gives colour to our hair, eyes and skin. The melanocyte lineage also gives rise to melanoma, the most lethal form of skin cancer. The melanocyte lineage differentiates from neural crest cells during development, and most melanocytes reside in the skin and hair, where they are replenished by melanocyte stem cells. Because the molecular mechanisms necessary for melanocyte specification, migration, proliferation and differentiation are co-opted during melanoma initiation and progression, studying melanocyte development is directly relevant to human disease. Here, through the lens of advances in cellular omic and genomic technologies, we review the latest findings in melanocyte development and differentiation, and how these developmental pathways become dysregulated in disease., Competing Interests: Competing interests E.E.P. is the Editor-in-Chief at Disease Models & Mechanisms published by The Company of Biologists, but was not included in any aspect of the editorial handling of this article or peer-review process., (© 2024. Published by The Company of Biologists Ltd.)

Protein kinases act as central molecular switches in the control of cellular functions. Alterations in the regulation and function of protein kinases may provoke diseases including cancer. In this study we investigate the conformational states of such disease-associated kinases using the high sensitivity of the kinase conformation (KinCon) reporter system. We first track BRAF kinase activity conformational changes upon melanoma drug binding. Second, we also use the KinCon reporter technology to examine the impact of regulatory protein interactions on LKB1 kinase tumor suppressor functions. Third, we explore the conformational dynamics of RIP kinases in response to TNF pathway activation and small molecule interactions. Finally, we show that CDK4/6 interactions with regulatory proteins alter conformations which remain unaffected in the presence of clinically applied inhibitors. Apart from its predictive value, the KinCon technology helps to identify cellular factors that impact drug efficacies. The understanding of the structural dynamics of full-length protein kinases when interacting with small molecule inhibitors or regulatory proteins is crucial for designing more effective therapeutic strategies., Competing Interests: VK, SS, AF, FE, JF, SS, SS, RW, JT, VS, PM, TK No competing interests declared, PT, ES ES and PT are co-founders of KinCon biolabs; KinCon-reporters are subject of patents (WO2018060415A1), (© 2024, Kugler, Schwaighofer et al.)

It is estimated that only 0.02% of disseminated tumour cells are able to seed overt metastases 1 . While this suggests the presence of environmental constraints to metastatic seeding, the landscape of host factors controlling this process remains largely unclear. Here, combining transposon technology 2 and fluorescence niche labelling 3 , we developed an in vivo CRISPR activation screen to systematically investigate the interactions between hepatocytes and metastatic cells. We identify plexin B2 as a critical host-derived regulator of liver colonization in colorectal and pancreatic cancer and melanoma syngeneic mouse models. We dissect a mechanism through which plexin B2 interacts with class IV semaphorins on tumour cells, leading to KLF4 upregulation and thereby promoting the acquisition of epithelial traits. Our results highlight the essential role of signals from the liver parenchyma for the seeding of disseminated tumour cells before the establishment of a growth-promoting niche. Our findings further suggest that epithelialization is required for the adaptation of CRC metastases to their new tissue environment. Blocking the plexin-B2-semaphorin axis abolishes metastatic colonization of the liver and therefore represents a therapeutic strategy for the prevention of hepatic metastases. Finally, our screening approach, which evaluates host-derived extrinsic signals rather than tumour-intrinsic factors for their ability to promote metastatic seeding, is broadly applicable and lays a framework for the screening of environmental constraints to metastasis in other organs and cancer types., (© 2024. The Author(s).)

Objective: 18 F-N-(2-(Diethylamino)ethyl)-5-(2-(2-(2-fluoroethoxy)ethoxy)ethoxy) picolinamide ( 18 F-PFPN) is a novel positron emission tomography (PET) probe designed to specifically targets melanin. This study aimed to evaluate the diagnostic feasibility of 18 F-PFPN in patients with ocular or orbital melanoma., Materials and Methods: Three patients with pathologically confirmed ocular or orbital melanoma (one male, two females; age 41-59 years) were retrospectively reviewed. Each patient underwent comprehensive 18 F-PFPN and 18 F-fluorodeoxyglucose ( 18 F-FDG) PET scans. The maximum standardized uptake value (SUV max ) of the lesion and the interference caused by background tissue were compared between 18 F-PFPN and 18 F-FDG PET imaging. In addition, the effect of intrinsic pigments in the uvea and retina on the interpretation of the results was examined. The contralateral non-tumorous eye of each patient served as a control., Results: All primary tumors (3/3) were detected using 18 F-PFPN PET, while only two primary tumors were detected using 18 F-FDG PET. Within each lesion, the SUV max of 18 F-PFPN was 2.6 to 8.3 times higher than that of 18 F-FDG. Regarding the quality of PET imaging, the physiological uptake of 18 F-FDG PET in the brain and periocular tissues limited the imaging of tumors. However, 18 F-PFPN PET minimized this interference. Notably, intrinsic pigments in the uvea and retina did not cause abnormal concentrations of 18 F-PFPN, as no anomalous uptake of 18 F-PFPN was detected in the healthy contralateral eyes., Conclusion: Compared to 18 F-FDG, 18 F-PFPN demonstrated higher detection rates for ocular and orbital melanomas with minimal interference from surrounding tissues. This suggests that 18 F-PFPN could be a promising clinical diagnostic tool for distinguishing malignant melanoma from benign pigmentation in ocular and orbital melanomas., Competing Interests: The authors have no potential conflicts of interest to disclose., (Copyright © 2024 The Korean Society of Radiology.)

Background: Sinonasal mucosal melanoma (SNMM) is a rare but aggressive tumor with a poor prognosis. The co-inhibitory receptors T cell immunoglobulin and mucinodomain containing-3 (TIM-3), lymphocyte activation gene-3 (LAG-3) and T cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain (TIGIT) are promising new targets in anti-cancer immunotherapy. The expression profiles of these immune checkpoint molecules (ICMs) and potential prognostic implications have not been characterized in SNMM yet., Methods: Immunohistochemical staining for TIGIT, LAG-3 and TIM-3 was performed on tumor tissue samples from 27 patients with primary SNMM. Associations between ICM expression and demographic parameters, AJCC tumor stage, overall survival, and recurrence-free survival were retrospectively analyzed., Results: SNMM patients with low numbers of TIGIT+ and TIM-3+ tumor infiltrating lymphocytes (TILs) in the primary tumor survived significantly longer than patients with a high degree of TIGIT+ and TIM-3+ TILs. High infiltration with TIM-3+ or TIGIT+ lymphocytes was associated with the higher T4 stage and decreased 5-year survival., Conclusion: We identified high densities of TIM-3+ and TIGIT+ TILs as strong negative prognostic biomarkers in SNMM. This suggests that TIM-3 and TIGIT contribute to immunosuppression in SNMM and provides a rationale for novel treatment strategies based on this next generation of immune checkpoint inhibitors. Prospective studies with larger case numbers are warranted to confirm our findings and their implications for immunotherapy., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper, (Copyright © 2024 The Authors. Published by Elsevier GmbH.. All rights reserved.)