bims-meladi Biomed News
on Melanocytes in development and disease
Issue of 2021‒05‒30
38 papers selected by
Farah Jaber-Hijazi
University of the West of Scotland

  1. Pigment Cell Melanoma Res. 2021 May 28.
      Human skin aging is a natural phenomenon that results from continuous exposure to intrinsic (time, genetic factors, hormones) as well as extrinsic factors (UV exposure, pollution, tobacco). In areas that are frequently exposed to the sun, photoaging blends with the process of intrinsic aging, resulting in an increased senescent cells number and consequently accelerating the aging process. The severity of photodamage depends on constitutional factors, including skin phototype (skin color, tanning capacity), intensity, and duration of sunlight/UV exposure. Aging affects nearly every aspect of cutaneous biology, including pigmentation. Clinically, the phenotype of age pigmented skin has a mottled, uneven color, primarily due to age spots, with or without hypopigmentation. Uneven pigmentation might be attributed to the hyperactivation of melanocytes, altered distribution of pigment, and turnover. In addition to direct damage to pigment-producing cells, photodamage alters the physiological crosstalk between keratinocytes, fibroblasts, endothelial cells, and melanocytes responsible for natural pigmentation homeostasis. Interestingly, age-independent diffuse expression of senescence-associated markers in the dermal and epidermal compartment is also associated with vitiligo, suggesting that premature senescence play an important role in the pathology.
    Keywords:  Skin; disorders of skin color; melanocytes; senescence; vitiligo
  2. Fac Rev. 2021 ;10 38
      The neural crest is a unique population of multipotent cells forming in vertebrate embryos. Their vast cell fate potential enables the generation of a diverse array of differentiated cell types in vivo. These include, among others, connective tissue, cartilage and bone of the face and skull, neurons and glia of the peripheral nervous system (including enteric nervous system), and melanocytes. Following migration, these derivatives extensively populate multiple germ layers. Within the competent neural border ectoderm, an area located at the junction between the neural and non-neural ectoderm during embryonic development, neural crest cells form in response to a series of inductive secreted cues including BMP, Wnt, and FGF signals. As cells become progressively specified, they express transcriptional modules conducive with their stage of fate determination or cell state. Those sequential states include the neural border state, the premigratory neural crest state, the epithelium-to-mesenchyme transitional state, and the migratory state to end with post-migratory and differentiation states. However, despite the extensive knowledge accumulated over 150 years of neural crest biology, many key questions remain open, in particular the timing of neural crest lineage determination, the control of potency during early developmental stages, and the lineage relationships between different subpopulations of neural crest cells. In this review, we discuss the recent advances in understanding early neural crest formation using cutting-edge high-throughput single cell sequencing approaches. We will discuss how this new transcriptomic data, from 2017 to 2021, has advanced our knowledge of the steps in neural crest cell lineage commitment and specification, the mechanisms driving multipotency, and diversification. We will then discuss the questions that remain to be resolved and how these approaches may continue to unveil the biology of these fascinating cells.
    Keywords:  fate specification; lineage specification; multipotency; neural crest; pluripotency; single cell transcriptomics
  3. RSC Med Chem. 2020 Nov 13. 12(3): 363-369
      Human tyrosinase (hTYR) and tyrosinase-related protein 1 (hTYRP1) are closely-related enzymes involved in the synthesis of melanin, which are selectively expressed in melanocytes and, in a pathological context, in melanoma lesions. We used a previously described tyrosinase inhibitor (Thiamidol™) and DNA-encoded library technology for the discovery of novel hTYR and hTYRP1 ligands, that could be used as vehicles for melanoma targeting. Performing de novo selections with DNA-encoded libraries, we discovered novel ligands capable of binding to both hTYR and hTYRP1. More potent ligands were obtained by multimerizing Thiamidol™ moieties, leading to homotetrameric structures that avidly bound to melanoma cells, as revealed by flow cytometry. These findings suggest that melanoma lesions may, in the future, be targeted not only by monoclonal antibody reagents but also by small organic ligands.
  4. J Invest Dermatol. 2021 May 21. pii: S0022-202X(21)01242-2. [Epub ahead of print]
      Opsin3 (OPN3) is a potential key regulator of human melanocyte melanogenesis. How OPN3-mediated regulation of melanocyte melanogenesis is triggered is largely unclear. Transforming growth factor-β (TGF-β) can inhibit the growth of human melanocytes and reduce melanin synthesis in melanocytes. However, whether TGF-β2 can modulate pigmentation in normal human primary melanocytes via OPN3 is entirely unknown. Here, we constructed a co-culture model with human epidermal melanocytes and keratinocytes. Higher OPN3, tyrosinase (TYR), tyrosinase-related protein (TRP)-1, and TRP-2 expression and higher tyrosinase activity were detected in co-cultured cells than in mono-cultured cells. Moreover, elevated levels of TGF-β2 were detected in the culture supernatant of melanocytes co-cultured with keratinocytes. OPN3 inhibition in melanocytes decreased TYR, TRP-1, and TRP-2 expression and downregulated tyrosinase activity. Our findings indicate that TGF-β2 upregulates TYR, TRP-1 and TRP-2 expression in human melanocytes via OPN3 and downstream calcium-dependent G protein-coupled signalling pathways to induce melanogenesis. Interestingly, treatment with the TGF-β2 receptor inhibitor LY2109761 (10 μM) did not inhibit TGF-β2-induced melanocyte melanogenesis via OPN3. Collectively, our data suggest that TGF-β2 upregulates tyrosinase activity via OPN3 through a TGF-β2R-independent and calcium-dependent G protein-coupled signalling pathway.
    Keywords:  OPN3; TGF-β2; human epidermal melanocytes; tyrosinase
  5. J Dermatol Sci. 2021 May 15. pii: S0923-1811(21)00104-3. [Epub ahead of print]
      BACKGROUND: Melanin plays important roles in determining human skin color and protecting human skin cells against harmful ultraviolet light. However, abnormal hyperpigmentation in some areas of the skin may become aesthetically unpleasing, resulting in the need for effective agents or methods to regulate undesirable hyperpigmentation.OBJECTIVE: We investigated the effect of harmine, a natural harmala alkaloid belonging to the beta-carboline family, on melanin synthesis and further explored the signaling pathways involved in its mechanism of action.
    METHODS: Human MNT-1 melanoma cells and human primary melanocytes were treated with harmine, chemical inhibitors, small interfering RNAs, or mammalian expression vectors. Cell viability, melanin content, and expression of various target molecules were assessed.
    RESULTS: Harmine decreased melanin synthesis and tyrosinase expression in human MNT-1 melanoma cells. Inhibition of DYRK1A, a harmine target, decreased melanin synthesis and tyrosinase expression. Further studies revealed that nuclear translocation of NFATC3, a potential DYRK1A substrate, was induced via the harmine/DYRK1A pathway and that NFATC3 knockdown increased melanin synthesis and tyrosinase expression. Suppression of melanin synthesis and tyrosinase expression via the harmine/DYRK1A pathway was significantly attenuated by NFATC3 knockdown. Furthermore, harmine also decreased melanin synthesis and tyrosinase expression through regulation of NFATC3 in human primary melanocytes.
    CONCLUSION: Our results indicate that harmine decreases melanin synthesis through regulation of the DYRK1A/NFATC3 pathway and suggest that the DYRK1A/NFATC3 pathway may be a potential target for the development of depigmenting agents.
    Keywords:  DYRK1A; Harmine; Melanin; NFATC3; Tyrosinase
  6. Zhonghua Yi Xue Za Zhi. 2021 Jun 01. 101(20): 1529-1534
      Objective: To investigate effect of Bimatoprost (BimP) on growth of reconstructed hair follicles in recipient nude mice. Methods: Primary epidermal and dermal cells were isolated from newborn C57BL/6J mice (1-day-old) skins, and the reconstructed hair follicles was implanted in the dorsal skin of Balb/c-nu nude mice using a silicon chamber protocol, then, the 18 nude mice were randomly divided into control group, BimP group and minoxidil group, with 6 mice in each group. After 2 weeks, topical treatment was applied to the grafted area of the nude mice by 2% minoxidil 100 μl, 0.03% BimP 100 μl and saline 100 μl, respectively, once daily for 2 weeks. At day 14 after treatment, the mice were euthanized to measure the length of dorsal hair, and the number and hair cycle of the reconstructed follicles was observed histologically. The total mRNA and proteins expression of Wnt3a, LEF1, β-catenin and Frizzled7 were determined by qPCR and Western Blotting. The distribution and expression of β-catenin in the reconstructed follicles was detected by immunofluorescence staining. Results: As compared to the control group, the BimP group had thicker and longer hair [(0.57±0.07) vs (0.36±0.05) cm, P<0.01], no significant difference was seen between the BimP and minoxidil group. The mRNA expression levels of Wnt3a (2.73±0.17 vs 1.00±0.14, P<0.01)、LEF1(1.71±0.12 vs 1.00±0.19, P<0.01)、β-catenin (2.37±0.21vs 1.00±0.11, P<0.01) and Frizzled7 (2.62±0.15vs 1.00±0.18, P<0.01) were significantly increased in BimP group compared with the control group. Western Blotting showed the same results, the protein expression levels of Wnt3a (1.44±0.21vs 1.00±0.13, P<0.05)、LEF1 (1.36±0.15 vs 1.00±0.09, P<0.05)、β-catenin (1.60±0.13 vs 1.00±0.16, P<0.01) and Frizzled7 (1.52±0.15 vs 1.00±0.21, P<0.05) in BimP group were higher than those in control group, and the difference was statistically significant. Immunofluorescence staining showed that β-catenin was strongly expressed in hair bulb cells and sebaceous gland cells of reconstructed hair follicles in BimP group and minoxidil group, whereas barely seen in the control group. Conclusion: BimP directly promotes growth of reconstructed hair follicles in mice by activating canonical Wnt/β-catenin signaling pathway.
  7. J Photochem Photobiol B. 2021 May 17. pii: S1011-1344(21)00095-6. [Epub ahead of print]220 112216
      Ultraviolet B (UVB) radiation induces mutagenic DNA photolesions in skin cells especially in form of cyclobutane pyrimidine dimers (CPDs). Protection mechanisms as DNA repair and apoptosis are of great importance in order to prevent skin carcinogenesis. In human skin, neural crest-derived precursors of melanocytes, the dermal stem cells (DSCs), are discussed to be at the origin of melanoma. Although they are constantly exposed to solar UV radiation, it is still not investigated how DSCs cope with UV-induced DNA damage. Here, we report a comparative study of the DNA damage response after irradiation with a physiological relevant UVB dose in DSCs in comparison to fibroblasts, melanocytes and keratinocytes isolated from human foreskin. Within our experimental settings, DSCs were able to repair DNA photolesions as efficient as the other skin cell types with solely keratinocytes repairing significantly faster. Interestingly, only fibroblasts showed significant alterations in cell cycle distribution in terms of a transient S phase arrest following irradiation. Moreover, with the applied UVB dose none of the examined cell types was prone to UVB-induced apoptosis. This may cause persistent genomic alterations and in case of DSCs it may have severe consequences for their daughter cells, the differentiated melanocytes. Altogether, this is the first study demonstrating a similar UV response in dermal stem cells compared to differentiated skin cells.
    Keywords:  Apoptosis; Cell cycle; DNA repair; Dermal stem cell; Ultraviolet radiation
  8. Melanoma Res. 2021 May 25.
      Melanoma is a highly heterogeneous tumor. The incidence of melanoma increases with age and its long-term prognosis is poor. The treatment of melanoma includes surgical removal, chemotherapy and immunotherapy; however, the effect of these treatments is limited on mutated melanoma. Osteopontin is an extracellular protein which is expressed in numerous kinds of cells; it is related to the proliferation and invasion of cancer cells as well as the development of tumor microenvironment. The relationship between osteopontin and metastasis of melanoma has been clarified in recent years. This review focuses on the expression of osteopontin in patients with melanoma and associated signaling pathways involved in development and metastasis of melanoma; the potential role of osteopontin in immune modulation and prognosis prediction is also discussed here.
  9. Sci Rep. 2021 May 25. 11(1): 10879
      Cytoglobin (CYGB) is a ubiquitously expressed protein with a protective role against oxidative stress, fibrosis and tumor growth, shown to be transcriptionally regulated under hypoxic conditions. Hypoxia-inducible CYGB expression is observed in several cancer cell lines and particularly in various melanoma-derived cell lines. However, reliable detection of hypoxia-inducible mRNA levels by qPCR depends on the critical choice of suitable reference genes for accurate normalization. Limited evidence exists to support selection of the commonly used reference genes in hypoxic models of melanoma. This study aimed to select the optimal reference genes to study CYGB expression levels in melanoma cell lines exposed to hypoxic conditions (0.2% O2) and to the HIF prolyl hydroxylase inhibitor roxadustat (FG-4592). The expression levels of candidate genes were assessed by qPCR and the stability of genes was evaluated using the geNorm and NormFinder algorithms. Our results display that B2M and YWHAZ represent the most optimal reference genes to reliably quantify hypoxia-inducible CYGB expression in melanoma cell lines. We further validate hypoxia-inducible CYGB expression on protein level and by using CYGB promoter-driven luciferase reporter assays in melanoma cell lines.
  10. Am J Clin Dermatol. 2021 May 25.
      The prognosis of patients with metastatic melanoma has substantially improved over the last years with the advent of novel treatment strategies, mainly immune checkpoint inhibitors and BRAF and MEK inhibitors. Given the survival benefit provided in the metastatic setting and the evidence from prospective clinical trials in the early stages, these drugs have been introduced as adjuvant therapies for high-risk resected stage III disease. Several studies have also investigated immune checkpoint inhibitors, as well as BRAF and MEK inhibitors, for neoadjuvant treatment of high-risk stage III melanoma, with preliminary evidence suggesting this could be a very promising approach in this setting. However, even with new strategies, the risk of disease recurrence varies widely among stage III patients, and no available biomarkers for predicting disease recurrence have been established to date. Improved risk stratification is particularly relevant in this setting to avoid unnecessary treatment for patients who have minimum risk of disease recurrence and to reduce toxicities and costs. Research for predictive and prognostic biomarkers in this setting is ongoing to potentially shed light on the complex interplay between the tumor and the host immune system, and to further personalize treatment. This review provides an insight into available data on circulating and tissue biomarkers, including the tumor microenvironment and associated gene signatures, and their predictive and prognostic role during neoadjuvant and adjuvant treatment for cutaneous high-risk melanoma patients.
  11. J Immunother. 2021 May 24.
      Immune checkpoint inhibitors (ICIs) have tremendously changed the therapeutic landscape of melanoma since they are associated with a durable response, allowing for intentional discontinuation of therapy after complete or partial remission. However, a subset of patients develops a relapse after cessation of ICI treatment and may not respond to reinduction of ICIs. The aim of the present study was to identify risk factors for relapse after intentional discontinuation of ICI therapy. Patients with intentional discontinuation of ICI therapy for metastatic or unresectable melanoma from 5 German university hospitals were analyzed retrospectively. Clinicopathologic and follow-up data of 87 patients were collected and analyzed by univariate and multivariate Cox proportional-hazards models. The following parameters were associated with relapse after cessation of ICI treatment in the univariate Cox regression analysis: concurrent radiotherapy and ICI, best overall response, and presence of brain metastases. Duration of treatment, type of primary tumor, body mass index, programmed-death ligand 1 expression, and lactate dehydrogenase levels did not significantly influence the risk for relapse. In the multivariate analysis, partial remission [hazard ratio 4.217 (95% confidence interval: 1.424-12.49), P=0.009] and stable disease [3.327 (1.204-9.19), P=0.02] were associated with a significant decrease in progression-free survival compared with complete remission. Concurrent radiotherapy and ICI [3.619 (1.288-10.168), P=0.015] are additional independent risk factors for decreased progression-free survival upon ICI discontinuation, whereas the presence of brain metastasis did not reach statistical significance on multivariate analysis.
  12. Front Immunol. 2021 ;12 661737
      The recent advent of targeted and immune-based therapies has revolutionized the treatment of melanoma and transformed outcomes for patients with metastatic disease. The majority of patients develop resistance to the current standard-of-care targeted therapy, dual BRAF and MEK inhibition, prompting evaluation of a new combination incorporating a CDK4/6 inhibitor. Based on promising preclinical data, combined BRAF, MEK and CDK4/6 inhibition has recently entered clinical trials for the treatment of BRAFV600 melanoma. Interestingly, while BRAF- and MEK-targeted therapy was initially developed on the basis of potent tumor-intrinsic effects, it was later discovered to have significant immune-potentiating activity. Recent studies have also identified immune-related impacts of CDK4/6 inhibition, though these are less well defined and can be both immune-potentiating and immune-inhibitory. BRAFV600 melanoma patients are also eligible to receive immunotherapy, specifically checkpoint inhibitors against PD-1 and CTLA-4. The immunomodulatory activity of BRAF/MEK-targeted therapies has prompted interest in combination therapies incorporating these with immune checkpoint inhibitors, however recent clinical trials investigating this approach have produced variable results. Here, we summarize the immunomodulatory effects of BRAF, MEK and CDK4/6 inhibitors, shedding light on the prospective utility of this combination alone and in conjunction with immune checkpoint blockade. Understanding the mechanisms that underpin the clinical efficacy of these available therapies is a critical step forward in optimizing novel combination and scheduling approaches to combat melanoma and improve patient outcomes.
    Keywords:  BRAF/MEK inhibition; CDK4/6 inhibition; immune checkpoint blockade; immunotherapy; melanoma; targeted therapeutic drugs
  13. Front Oncol. 2021 ;11 666624
      The improvement of the immunotherapeutic potential in most human cancers, including melanoma, requires the identification of increasingly detailed molecular features underlying the tumor immune responsiveness and acting as disease-associated biomarkers. In recent past years, the complexity of the immune landscape in cancer tissues is being steadily unveiled with a progressive better understanding of the plethora of actors playing in such a scenario, resulting in histopathology diversification, distinct molecular subtypes, and biological heterogeneity. Actually, it is widely recognized that the intracellular patterns of alterations in driver genes and loci may also concur to interfere with the homeostasis of the tumor microenvironment components, deeply affecting the immune response against the tumor. Among others, the different events linked to genetic instability-aneuploidy/somatic copy number alteration (SCNA) or microsatellite instability (MSI)-may exhibit opposite behaviors in terms of immune exclusion or responsiveness. In this review, we focused on both prevalence and impact of such different types of genetic instability in melanoma in order to evaluate whether their use as biomarkers in an integrated analysis of the molecular profile of such a malignancy may allow defining any potential predictive value for response/resistance to immunotherapy.
    Keywords:  aneuploidy; immunotherapy response; melanoma; microsatellite instability; tumor mutation burden
  14. Melanoma Res. 2021 May 25.
      Systemic treatment options with proven efficacy for the treatment of metastatic uveal melanoma are limited. In this study, we aimed to evaluate the efficacy of nivolumab in metastatic uveal melanoma patients. In our multi-center study, the files of patients who received nivolumab treatment with a diagnosis of metastatic uveal melanoma were retrospectively reviewed and their information was recorded. Seventeen patients were enrolledand 16 patients were evaluable for efficacy. The objective response rate (ORR) was 18% including one confirmed complete response and two confirmed partial responses. The median progression-free survival (PFS) was 5.8 months (95% CI, 0.03-11.57 months), and the median overall survival (OS) was 10.5 months (95% CI, 3.87-14.14 months). Significant longer OS and PFS were observed in patients with the performance status of the Eastern Cooperative Oncology Group (ECOG-PS) 0. Although significant longer OS was detected in patients with low median lactate dehydrogenase (LDH) levels, no significant difference was found in PFS. Grade 1 and 2 fatigue and decreased appetite were the most common side effects associated with treatment (17%); grade 3 and 4 side effects were not observed. Immunotherapy is also emerging as a treatment option among the limited number of treatment options in metastatic uveal melanoma (mUM), but its efficacy needs to be demonstrated with prospective studies involving a larger number of patients.
  15. Arkh Patol. 2021 ;83(3): 30-34
      Certain difficulties arise in the differential diagnosis between Reed nevus that is common in children and adolescents and cutaneous melanoma that is extremely rare in patients of this age group. In addition to the classical histological examination, an immunohistochemical test for marker proteins is carried out to improve the accuracy of the diagnosis of pigmented skin neoplasms.OBJECTIVE: To evaluate the suitability of a set of proteins (cyclin D1, p16INK4a, and HLA class I antigens) in the differential diagnosis of Reed nevus and cutaneous melanoma in children and adolescents.
    MATERIAL AND METHODS: Three samples of pigmented skin neoplasms were taken during surgical treatment in patients at the Blokhin National Medical Research Center of Oncology: two samples of Reed nevus (from a 9-year-old girl and a 15-year-old boy) and a sample of cutaneous melanoma that had developed in an 8-year-old boy. The materials were presented by paraffin blocks. Immunohistochemical staining was performed using antibodies against cyclin D1, p16INK4a, and HLA class I antigens.
    RESULTS: Differences were found between nevus and melanoma in the expression of all three markers. Thus, the nuclear expression of cyclin D1, a proliferation activator, occurred in some cells in the nevus samples and in the vast majority of cells in the melanoma samples. The nuclear expression of the cell cycle inhibitor p16INK4a was dramatically reduced in melanoma compared to nevus. HLA class I antigens were detected on the surface of individual nevus cells, but were completely absent on the membranes and in the cytoplasm of melanoma cells, which could promote the evasion of this tumor from the body's immunological supervision.
    CONCLUSION: Immunohistochemical test for the proteins cyclin D1, p16INK4a, and HLA class 1 antigens is a promising approach to differentially diagnosing between Reed nevus and cutaneous melanoma in children and adolescents.
    Keywords:  Reed nevus; differential diagnosis; immunohistochemistry; melanoma
  16. BMJ Case Rep. 2021 May 27. pii: e241981. [Epub ahead of print]14(5):
      Treatment with immune checkpoint inhibitors (ICI) has drastically improved the prognosis for melanoma patients, but immune-mediated adverse events can occur in any organ, including the pituitary. In ICI-induced hypophysitis, lymphocytic infiltration and hypersensitivity reactions cause headache and pituitary deficiency. Most cases with ICI-induced hypophysitis develop central adrenal insufficiency. Here, we describe three patients treated with anticytotoxic T-lymphocyte-associated protein 4 (ipilimumab) for metastatic malignant melanoma: case 1 was asymptomatic when hypocortisolism was suspected; case 2 had symptoms of hypocortisolism and suspected severe systemic infection; case 3 had unspecific fatigue. In all cases, routine cortisol measurements and clinical suspicion (cases 2 and 3) led to the diagnosis of adrenocortical hormone (ACTH) deficiency and thereby central adrenal insufficiency. Undiagnosed and untreated, central adrenal insufficiency results in adrenal crisis. In patients treated with ICI, particularly, ipilimumab, hypophysitis and ACTH deficiency must be considered if morning cortisol is low or unspecific clinical symptoms of hypocortisolism are present.
    Keywords:  cancer intervention; endocrine system; immunology; pituitary disorders; skin cancer
  17. BMJ Case Rep. 2021 May 24. pii: e239496. [Epub ahead of print]14(5):
      Primary leptomeningeal melanomas are rare, comprising less than one percent of all brain tumours. They are aggressive and radioresistant tumours, with a poor prognosis. The mainstay of treatment is complete surgical resection and chemotherapy with limited success. Distinguishing a primary leptomeningeal melanoma from the more common metastatic disease can be difficult, and often requires the use of ancillary molecular testing. Primary central nervous system melanomas, including uveal melanomas, frequently exhibit mutations in GNAQ and GNA11, rare in the cutaneous and mucosal counterparts.A case of a primary leptomeningeal melanoma of the cerebellopontine angle is described. Molecular studies identified a GNA11 p.Q209L and a KIT p.M541L missense variant, with losses of chromosomes 1p and 3p demonstrated with cytogenetic studies. Complete surgical resection was not possible and leptomeningeal metastatic disease rapidly ensued despite immunotherapy. Further understanding of the molecular signature may translate to improved diagnosis, prognostication and development of targeted therapies.
    Keywords:  neuro genetics; neurooncology; pathology
  18. JCO Precis Oncol. 2021 ;pii: PO.20.00119. [Epub ahead of print]5
      PURPOSE: Current guidelines for postoperative management of patients with stage I-IIA cutaneous melanoma (CM) do not recommend routine cross-sectional imaging, yet many of these patients develop metastases. Methods that complement American Joint Committee on Cancer (AJCC) staging are needed to improve identification and treatment of these patients. A 31-gene expression profile (31-GEP) test predicts metastatic risk as low (class 1) or high (class 2). Prospective analysis of CM outcomes was performed to test the hypotheses that the 31-GEP provides prognostic value for patients with stage I-III CM, and that patients with stage I-IIA melanoma and class 2 31-GEP results have metastatic risk similar to patients for whom surveillance is recommended.MATERIALS AND METHODS: Two multicenter registry studies, INTEGRATE ( identifier:NCT02355574) and EXPAND ( identifier:NCT02355587), were initiated under institutional review board approval, and 323 patients with stage I-III CM and median follow-up time of 3.2 years met inclusion criteria. Primary end points were 3-year recurrence-free survival (RFS), distant metastasis-free survival (DMFS), and overall survival (OS).
    RESULTS: The 31-GEP was significant for RFS, DMFS, and OS in a univariate analysis and was a significant, independent predictor of RFS, DMFS, and OS in a multivariable analysis. GEP class 2 results were significantly associated with lower 3-year RFS, DMFS, and OS in all patients and those with stage I-IIA disease. Patients with stage I-IIA CM and a class 2 result had recurrence, distant metastasis, and death rates similar to patients with stage IIB-III CM. Combining 31-GEP results and AJCC staging enhanced sensitivity over each approach alone.
    CONCLUSION: These data provide a rationale for using the 31-GEP along with AJCC staging, and suggest that patients with stage I-IIA CM and a class 2 31-GEP signature may be candidates for more intense follow-up.
  19. Surg Pathol Clin. 2021 Jun;pii: S1875-9181(21)00017-9. [Epub ahead of print]14(2): 341-357
      Dysplastic nevi are distinctive melanocytic lesions in the larger group of atypical nevi. They often are multiple and sporadic with genetic features intermediate between common acquired nevi and melanoma. Dysplastic nevi may be multiple, familial, and seen in patients with familial melanoma syndrome. Although their behavior is benign, they rarely represent a precursor to melanoma. If clinically suspicious, dysplastic nevi should be removed for adequate histopathologic examination and to exclude possibility of melanoma. Partial sampling should be avoided because reliable separation from melanoma requires visualization of the entire lesion to allow for examination of architectural histopathologic features and avoid sampling error.
    Keywords:  Dysplastic nevus; Familial melanoma; Melanocytic; Melanoma; Neoplasm
  20. Sci Rep. 2021 May 26. 11(1): 11023
      BRAF inhibitors (BRAFi) selectively target oncogenic BRAFV600E/K and are effective in 80% of advanced cutaneous malignant melanoma cases carrying the V600 mutation. However, the development of drug resistance limits their clinical efficacy. Better characterization of the underlying molecular processes is needed to further improve treatments. We previously demonstrated that transcription of PTEN is negatively regulated by the PTEN pseudogene antisense RNA, PTENP1-AS, and here we investigated the impact of this transcript on clinical outcome and BRAFi resistance in melanoma. We observed that increased expression levels of PTENP1-AS in BRAFi resistant cells associated with enrichment of EZH2 and H3K27me3 at the PTEN promoter, consequently reducing the expression levels of PTEN. Further, we showed that targeting of the PTENP1-AS transcript sensitized resistant cells to BRAFi treatment and that high expression of PTENP1-AS in stage III melanoma correlated with poor survival. Collectively, the data presented here show that PTENP1-AS is a promising target for re-sensitizing cells to BRAFi and also a possible prognostic marker for clinical outcome in stage III melanoma.
  21. Melanoma Res. 2021 May 25.
      OBJECTIVE: Melanoma is a malignant tumor with high metastasis and mortality. Epithelial-mesenchymal transition (EMT) was reported to be involved in the growth and metastasis of melanoma. To investigate these sections further, we showed that E26 transformation specific 1 (ETS1) could regulate growth, metastasis and EMT process of melanoma by regulating microRNA(miR)-16/SRY-related HMG box (SOX) 4 expression.METHODS: MiR-16, ETS1, SOX4 and nuclear factor κB (NF-κB) expression levels in melanoma cells were examined using qPCR. ETS1, SOX4, EMT-related proteins and NF-κB signaling pathway-related proteins were examined using western blot. Cell counting kit-8 assay, transwell assay were applied to evaluate the cell proliferation, migration and invasion of melanoma cells, respectively. Besides, a dual-luciferase reporter assay was employed to verify the binding relationship between ETS1 and miR-16, miR-16 and SOX4, miR-16 and NF-κB1.
    RESULTS: We showed that ETS1 and SOX4 were upregulated in melanoma cells, while miR-16 was downregulated. MiR-16 overexpression suppressed growth, metastasis and EMT process of melanoma. We found ETS1 could bind to the promoter region of miR-16 and inhibited its transcription. ETS1 silence could inhibit growth, metastasis and EMT process of melanoma, and inhibition of miR-16 could reverse the effects. Besides, miR-16 is directly bound to SOX4 and downregulated its expression. Rescued experiments confirmed that SOX4 overexpression abolished the inhibition effect of miR-16 mimics on growth, metastasis and EMT process of melanoma. Finally, NF-κB1 as the target of miR-16 mediated downstream biological responses.
    CONCLUSION: ETS1 activated NF-κB signaling pathway through miR-16 via targeting SOX4, thus promoting growth, metastasis and EMT of melanoma.
  22. Front Oncol. 2021 ;11 667715
      Melanoma skin cancer is extremely aggressive with increasing incidence and mortality. Among the emerging therapeutic targets in the treatment of cancer, the family of transient receptor potential channels (TRPs) has been reported as a possible pharmacological target. Specifically, the ankyrin subfamily, representing TRPA1 channels, can act as a pro-inflammatory hub. These channels have already been implicated in the control of intracellular metabolism in several cell models, but little is known about their role in immune cells, and how it could affect tumor progression in a process known as immune surveillance. Here, we investigated the participation of the TRPA1 channel in the immune response against melanoma tumor progression in a mouse model. Using Trpa1 +/+ and Trpa1 -/- animals, we evaluated tumor progression using murine B16-F10 cells and assessed isolated CD8+ T cells for respiratory and cytotoxic functions. Tumor growth was significantly reduced in Trpa1 -/- animals. We observed an increase in the frequency of circulating lymphocytes. Using a dataset of CD8+ T cells isolated from metastatic melanoma patients, we found that TRPA1 reduction correlates with several immunological pathways. Naïve CD8+ T cells from Trpa1 +/+ and Trpa1 -/- animals showed different mitochondrial respiration and glycolysis profiles. However, under CD3/CD28 costimulatory conditions, the absence of TRPA1 led to an even more extensive metabolic shift, probably linked to a greater in vitro killling ability of Trpa1 -/- CD8+ T cells. Therefore, these data demonstrate an unprecedented role of TRPA1 channel in the metabolism control of the immune system cells during carcinogenesis.
    Keywords:  CD8+ T cells; TRPA1 channel; immunometabolism; melanoma; metabolic shift
  23. Front Immunol. 2021 ;12 663865
      Background: Ipilimumab improves survival for patients with metastatic malignant melanoma. Combining a therapeutic cancer vaccine with ipilimumab may increase efficacy by providing enhanced anti-tumor immune responses. UV1 consists of three synthetic long peptides from human telomerase reverse transcriptase (hTERT). These peptides comprise epitopes recognized by T cells from cancer patients experiencing long-term survival following treatment with a first-generation hTERT vaccine, and generate long-lasting immune responses in cancer patients when used as monotherapy. The objective of this trial was to investigate the safety and efficacy of combining UV1 with ipilimumab in metastatic melanoma.Patients and Methods: In this phase I/IIa, single center trial [NCT02275416], patients with metastatic melanoma received repeated UV1 vaccinations, with GM-CSF as an adjuvant, in combination with ipilimumab. Patients were evaluated for safety, efficacy and immune response. Immune responses against vaccine peptides were monitored in peripheral blood by measuring antigen-specific proliferation and IFN-γ production.
    Results: Twelve patients were recruited. Adverse events were mainly diarrhea, injection site reaction, pruritus, rash, nausea and fatigue. Ten patients showed a Th1 immune response to UV1 peptides, occurring early and after few vaccinations. Three patients obtained a partial response and one patient a complete response. Overall survival was 50% at 5 years.
    Conclusion: Treatment was well tolerated. The rapid expansion of UV1-specific Th1 cells in the majority of patients indicates synergy between UV1 vaccine and CTLA-4 blockade. This may have translated into clinical benefit, encouraging the combination of UV1 vaccination with standard of care treatment regimes containing ipilimumab/CTLA-4 blocking antibodies.
    Keywords:  ipilimumab; melanoma; peptide vaccine immunotherapy; phase I/IIa studies; telomerase (hTERT)
  24. Clin Cancer Res. 2021 May 25. pii: clincanres.CCR-21-1694-E.2021. [Epub ahead of print]
      PURPOSE: Melanoma brain metastases (MBM) and leptomeningeal metastases (LMM) are two different manifestations of melanoma CNS metastasis. Here, we used single cell RNA-Seq (scRNA-Seq) to define the immune landscape of MBM, LMM and melanoma skin metastases.EXPERIMENTAL DESIGN: Single cell RNA-sequencing (scRNA-Seq) was undertaken on 43 patient specimens; including 8 skin metastases, 14 MBM and 19 serial LMM specimens. Detailed cell type curation was performed, the immune landscapes mapped and key results validated by IHC and flow cytometry. Association analyses were undertaken to identify immune cell subsets correlated with overall survival.
    RESULTS: The LMM microenvironment was characterized by an immune-suppressed T-cell landscape distinct from that of brain and skin metastases. An LMM patient with long-term survival demonstrated an immune repertoire distinct from that of poor survivors and more similar to normal CSF. Upon response to PD-1 therapy, this extreme responder showed increased levels of T-cells and dendritic cells in their CSF, whereas poor survivors showed little improvement in their T-cell responses. In MBM patients, therapy led to increased immune infiltrate, with similar T-cell transcriptional diversity noted between skin metastases and MBM. A correlation analysis across the entire immune landscape identified the presence of a rare population of dendritic cells (DC3s) that was associated with increased overall survival and positivelyregulated the immune environment through modulation of activated T-cells and MHC expression.
    CONCLUSION: Our study provides the first atlas of two distinct sites of melanoma CNS metastases and defines the immune cell landscape that underlies the biology of this devastating disease.
  25. J Invest Dermatol. 2021 May 25. pii: S0022-202X(21)01243-4. [Epub ahead of print]
      Melanoma cells are relatively resistant to ER stress, which contributes to tumor progression under stressful conditions and renders tolerance to ER stress-inducing therapeutic agents. Mitochondria are tightly interconnected with ER. However, whether mitochondria play a role in regulating ER stress resistance in melanoma remains elusive. Herein, we reported that the XBP1-MARCH5-MFN2 axis conferred ER stress resistance by coordinating mitochondrial fission and mitophagy in melanoma. Our integrative bioinformatics first revealed that the down-regulation of mitochondrial genes was highly correlated with UPR activation in melanoma. Then we proved that mitochondrial fission and mitophagy were prominently induced to contribute to ER stress resistance both in vitro and in vivo by maintaining mitochondrial function. Mechanistically, the activation of IRE1α/ATF6-XBP1 branches of UPR promoted the transcription of E3 ligase MARCH5 to facilitate the ubiquitination and degradation of MFN2, which thereby triggered mitochondrial fission and mitophagy under ER stress. Together, our findings demonstrate a regulatory axis that links mitochondrial fission and mitophagy to the resistance to ER stress. Targeting mitochondrial quality control machinery can be exploited as an approach to reinforce the efficacy of ER stress-inducing agents against cancer.
    Keywords:  ER stress; MFN2; melanoma; mitochondrial fission; mitophagy
  26. Melanoma Res. 2021 May 25.
      The treatment of metastatic melanoma has been revolutionised with the emergence of checkpoint inhibitors. The combination of Ipilimumab and Nivolumab offers the longest overall survival but is considerably more toxic than single-agent therapy. For patients who received single-agent immunotherapy it is unclear whether second-line immunotherapy is efficacious or tolerable. This study looked at outcomes for patients treated with sequential immunotherapy and compared them to patients who received dual immunotherapy. Fifty-eight patients received both Ipilimumab and an anti-PD-1 agent during the 5-year period, twenty-seven received dual immunotherapy, twenty received first-line Ipilimumab and eleven received an anti-PD-1 agent first line. The median overall survival (OS) was 24.8 months. The 5 year survival was greatest in patients treated with dual immunotherapy (42%) compared to first-line anti-PD-1 (33.3%) and first-line Ipilimumab (0%). As second-line treatments, anti-PD-1 agents had a median OS of 16.5 months compared to Ipilimumab at 3.4 months. 77.8% of patients had grade 3/4 toxicity with dual immunotherapy compared to 10% of patients treated with first-line Ipilimumab and 0% with anti-PD-1 agents. In the second line, 72.7% of patients treated with Ipilimumab experienced grade 3/4 toxicity, compared to 20% of patients treated with second-line anti-PD-1 agents. This study suggests Ipilimumab is not efficacious in patients who progress after anti-PD-1 agents, and this sequential approach does not avoid toxicity. The emergence of new checkpoint inhibitors will hopefully provide more efficacious treatment options for patients unable to tolerate Ipilimumab.
  27. J Immunother. 2021 May 24.
      Premelanosome protein (PMEL) is crucial for the formation of melanosomal fibrils through the transition from stage I to stage II melanosomes. It was used as a target antigen in some adoptive T-cell therapy of melanoma. The correlation of PMEL to prognosis and immune cell infiltration level are unknown in melanoma. The PMEL expression was evaluated via Tumor Immune Estimation Resource, Oncomine and Gene Expression Profiling Interactive Analysis (GEPIA). We also evaluate the influence of PMEL on overall survival via GEPIA, PrognoScan, and immunohistochemistry in human tissue microarray. The correlation between PMEL expression level and immune cell or gene markers of immune infiltration level was explored on Tumor Immune Estimation Resource and GEPIA. PMEL expression was significantly higher in skin cutaneous melanoma (SKCM) and SKCM-metastasis in comparison with the other cancers. In SKCM, PMEL expression in high levels was associated with poor overall survival. In both SKCM and SKCM-metastasis patients, PMEL expression is negatively correlated with the infiltration cells of CD8+ T cells, macrophages, and neutrophils. Programmed cell-death protein 1 just showed response rates ranging from 20% to 40% in patients with melanoma, so it is critical to discover a new therapeutic target. PMEL is negatively associated with immune cell infiltration and can be as a negative prognosis marker or new immunotherapy target in SKCM and SKCM-metastasis.
  28. Medicine (Baltimore). 2021 May 28. 100(21): e26017
      ABSTRACT: Skin melanoma remains a highly prevalent and yet deadly form of cancer, with the exact degree of melanoma-associated mortality being strongly dependent upon the local tumor microenvironment. The exact composition of stromal and immune cells within this microenvironmental region has the potential to profoundly impact melanoma progression and prognosis. As such, the present study was designed with the goal of clarifying the predictive relevance of stromal and immune cell-related genes in melanoma patients through comprehensive bioinformatics analyses. We therefore analyzed melanoma sample gene expression within The Cancer Genome Atlas database and employed the ESTIMATE algorithm as a means of calculating both stromal and immune scores that were in turn used for identifying differentially expressed genes (DEGs). Subsequently, univariate analyses were used to detect DEGs associated with melanoma patient survival, and through additional functional enrichment analyses, we determined that these survival-related DEGs are largely related to inflammatory and immune responses. A prognostic signature comprised of 10 genes (IL15, CCL8, CLIC2, SAMD9L, TLR2, HLA.DQB1, IGHV1-18, RARRES3, GBP4, APOBEC3G) was generated. This 10-gene signature effectively separated melanoma patients into low- and high-risk groups based upon their survival. These low- and high-risk groups also exhibited distinct immune statuses and differing degrees of immune cell infiltration. In conclusion, our results offer novel insights into a number of microenvironment-associated genes that impact survival outcomes in melanoma patients, potentially highlighting these genes as viable therapeutic targets.
  29. J Leukoc Biol. 2021 May 27.
      Evidence shows that tumor cells abundantly produce and release extracellular vesicles (EVs) that can interact with stromal cells and modulate their functions. In the tumor neighborhood, neutrophils can assume both antitumor and pro-tumor phenotypes, known as TAN-N1 and TAN-N2, respectively. Nevertheless, the contribution of tumor-derived EVs to the modulation of TAN phenotypes is still poorly understood. The effects of EVs produced by a metastatic human melanoma cell line (MV3) on the differentiation and functional changes in human neutrophils were investigated. Treatment with MV3-derived EVs induced neutrophil chemotaxis through a signaling pathway involving the CXCR2/PI3K-Akt axis, prolonged neutrophil life span, promoted formation of neutrophil extracellular traps with poor elastase activity, and increased reactive oxygen species production. In contrast, EVs also increased the expression of TAN-N2 molecular markers (such as ARG1, CXCR4, and VEGF) in neutrophils. They also impaired oxide nitric and peroxynitrite production and diminished cytotoxic activity against melanoma cells, inducing neutrophils into a pro-tumor profile. Remarkably, EV-stimulated neutrophils did not exhibit phagocytic activity. These data suggested that melanoma-derived EVs could activate neutrophils, allowing their migration toward the tumor microenvironment, and driving these cells to a pro-tumor/N2 polarization, thus contributing to tumor progression.
    Keywords:  cancer; inflammation; melanoma; tumor-associated neutrophils
  30. Research (Wash D C). 2021 ;2021 9780943
      Melanoma is a serious malignant skin tumor. Effectively eliminating melanoma and healing after-surgical wounds are always challenges in clinical studies. To address these problems, we propose manganese-doped calcium silicate nanowire-incorporated alginate hydrogels (named MCSA hydrogels) for in situ photothermal ablation of melanoma followed by the wound healing process. The proposed MCSA hydrogel had controllable gelation properties, reasonable strength, and excellent bioactivity due to the incorporated calcium silicate nanowires as the in situ cross-linking agents and bioactive components. The doping of manganese into calcium silicate nanowires gave them excellent photothermal effects for eradicating melanoma effectively under near infrared (NIR) irradiation. Moreover, the synergistic effect of manganese and silicon in the MCSA hydrogel effectively promotes migration and proliferation of vascular endothelial cells and promotes angiogenesis. Hence, such bifunctional bioactive hydrogels could achieve combined functions of photothermal therapy and wound healing, showing great promise for melanoma therapy and tissue regeneration.
  31. Sci Rep. 2021 May 27. 11(1): 11221
      Acid ceramidase (AC) is a lysosomal hydrolase encoded by the ASAH1 gene, which cleaves ceramides into sphingosine and fatty acid. AC is expressed at high levels in most human melanoma cell lines and may confer resistance against chemotherapeutic agents. One such agent, doxorubicin, was shown to increase ceramide levels in melanoma cells. Ceramides contribute to the regulation of autophagy and apoptosis. Here we investigated the impact of AC ablation via CRISPR-Cas9 gene editing on the response of A375 melanoma cells to doxorubicin. We found that doxorubicin activates the autophagic response in wild-type A375 cells, which effectively resist apoptotic cell death. In striking contrast, doxorubicin fails to stimulate autophagy in A375 AC-null cells, which rapidly undergo apoptosis when exposed to the drug. The present work highlights changes that affect melanoma cells during incubation with doxorubicin, in A375 melanoma cells lacking AC. We found that the remarkable reduction in recovery rate after doxorubicin treatment is strictly associated with the impairment of autophagy, that forces the AC-inhibited cells into apoptotic path.
  32. BMJ Case Rep. 2021 May 28. pii: e243723. [Epub ahead of print]14(5):
      In recent years, immunotherapy has revolutionised the treatment landscape for oncology patients with improved survival rates in cancers which previously had a dismissal prognosis. These agents target specific pathways of inhibition such as programmed cell death -1 (PD-1), PD ligand-1 and cytotoxic T-lymphocyte-associated antigen 4 resulting in stimulation of T cell activity. This results in enabling an individual's own immune system to fight against cancer, a different modality of treatment when compared with traditional chemotherapy. While attacking the tumour cells, there is an increased chance of host tissue immune reactions.We report a case of a patient who received immunotherapy for metastatic malignant melanoma. During the course of the treatment, development of a sarcoid-like reaction was histologically confirmed in the mediastinal lymph nodes. The patient had no respiratory symptoms and continued on the immunotherapy treatment with good clinical and radiological response.
    Keywords:  immunology; respiratory system; skin cancer
  33. Surg Pathol Clin. 2021 Jun;pii: S1875-9181(21)00011-8. [Epub ahead of print]14(2): 165-175
      PRAME (PReferentially expressed Antigen in MElanoma) is a melanoma-associated antigen expressed in cutaneous and ocular melanomas and some other malignant neoplasms, while its expression in normal tissue and benign tumors is limited. Detection of PRAME protein expression by immunohistochemistry in a cohort of 400 melanocytic tumors showed diffuse nuclear immunoreactivity for PRAME in most metastatic and primary melanomas. In contrast, most nevi were negative for PRAME or showed nondiffuse immunoreactivity. The difference in the extent of immunoreactivity for PRAME in unambiguous melanocytic tumors prompted the study of PRAME as an ancillary tool for evaluating melanocytic lesions in more challenging scenarios.
    Keywords:  Immunohistochemistry; Melanoma; Nevus; PReferentially expressed Antigen in MElanoma
  34. J Immunother Cancer. 2021 May;pii: e002214. [Epub ahead of print]9(5):
      BACKGROUND: Experimental cancer vaccines are traditionally administered by injection in subcutaneous tissue or muscle, commonly with adjuvants that create chronic inflammatory depots. Injection of melanoma-derived peptides induces T cell responses; however, the depots that form following injection may inhibit optimization of the immune response. In skin, epidermal Langerhans cells (LC) are a dominant source of professional antigen presenting cells. We hypothesized that: (1) applying melanoma-derived peptides topically, in proximity to LC, could be immunogenic and safe, with low vaccine-site toxicity and (2) topical toll-like receptor 7 (TLR7) agonist would increase immunogenicity of the peptide vaccine.METHODS: Twelve melanoma peptides plus a tetanus helper peptide were combined with granulocyte macrophage colony stimulating factor (GM-CSF) and were administered topically on days 1, 8, and 15, to 28 patients randomized to one of four adjuvant preparations: (1) incomplete Freund's adjuvant (IFA); (2) IFA plus a TLR7 agonist (imiquimod) administered on days 0, 7, 14; (3) dimethyl sulfoxide (DMSO) or (4) DMSO+ imiquimod administered on day 0, 7, 14. Every 3 weeks thereafter (x 6), the peptides were combined with GM-CSF and were injected into the dermis and subcutis in an emulsion with IFA. Toxicities were recorded and immune responses assayed by ELIspot.
    RESULTS: CD8+ T cell responses to transdermal vaccination in DMSO occurred in 83% of participants in group 3 and 86% in group 4, and responses to vaccination in IFA were observed in 29% of participants in group 1 and 14% in group 2. Overall, 61% of participants had CD4+ T cell immune responses to the tetanus peptide, with large, durable responses in groups 3 and 4. Five of seven participants in group 4 had a severe rash, one that was dose limiting. Ten-year overall survival was 67% and disease-free survival was 44%.
    CONCLUSIONS: These data provide proof of principle for immunogenicity in humans of transdermal immunization using peptides in DMSO. Further study is warranted into the pharmacokinetics and immunobiology of TLR agonists as vaccine adjuvants during transcutaneous application. Overall survival is high, supporting further investigation of this immunization approach.
    Keywords:  adjuvants; clinical trials as topic; immunogenicity; immunologic; melanoma; vaccine
  35. Front Immunol. 2021 ;12 663495
      Background: The tumor microenvironment (TME) involves infiltration of multiple immune cell subsets, which could influence the prognosis and clinical characteristics. The increasing evidence on the role of tumor-infiltrating lymphocytes (TILs) in primary and metastatic melanomas supports that the immune system is involved in the progression and outcomes of melanoma. However, the immune infiltration landscape in melanoma has not been systematically elucidated.Methods: In this study, we used CIBERSORT and ESTIMATE algorithms to analyze immune infiltration pattern of 993 melanoma samples. Then we screened differential expression genes (DEGs) related to immune subtypes and survival. The immune cell infiltration (ICI) score was constructed by using principal-component analysis (PCA) based on immune signature genes from DGEs. Gene set enrichment analysis (GSEA) was applied to explore high and low ICI score related pathways. Finally, the predictive ability of ICI score was evaluated in survival prognosis and immunotherapy benefit.
    Result: We identified three ICI clusters and three gene clusters associated with different immune subtypes and survival outcomes. Then the ICI score was constructed, and we found that high ICI score exhibited activated immune characteristics and better prognosis. High ICI score was significantly enriched in immune pathways and highly expressed immune signature genes. More importantly, we confirmed that melanoma patients with high ICI score had longer overall survival and rate of response to immunotherapy.
    Conclusion: We presented a comprehensive immune infiltration landscape in melanoma. Our results will facilitate understanding of the melanoma tumor microenvironment and provide a new immune therapy strategy.
    Keywords:  immune cell infiltration; immune therapy; melanoma; prognosis; tumor microenvironment
  36. Front Immunol. 2021 ;12 659444
      Aim: Immunotherapy shows efficacy in only a subset of melanoma patients. Here, we intended to construct a risk score model to predict melanoma patients' sensitivity to immunotherapy.Methods: Integration analyses were performed on melanoma patients from high-dimensional public datasets. The CD8+ T cell infiltration related genes (TIRGs) were selected via TIMER and CIBERSORT algorithm. LASSO Cox regression was performed to screen for the crucial TIRGs. Single sample gene set enrichment analysis (ssGSEA) and ESTIMATE algorithm were used to evaluate the immune activity. The prognostic value of the risk score was determined by univariate and multivariate Cox regression analysis.
    Results: 184 candidate TIRGs were identified in melanoma patients. Based on the candidate TIRGs, melanoma patients were classified into three clusters which were characterized by different immune activity. Six signature genes were further screened out of 184 TIRGs and a representative risk score for patient survival was constructed based on these six signature genes. The risk score served as an indicator for the level of CD8+ T cell infiltration and acted as an independent prognostic factor for the survival of melanoma patients. By using the risk score, we achieved a good predicting result for the response of cancer patients to immunotherapy. Moreover, pan-cancer analysis revealed the risk score could be used in a wide range of non-hematologic tumors.
    Conclusions: Our results showed the potential of using signature gene-based risk score as an indicator to predict melanoma patients' sensitivity to immunotherapy.
    Keywords:  CD8+ T cells; immune response; immunotherapy; melanoma; single cell RNA sequencing analysis
  37. J Invest Dermatol. 2021 May 21. pii: S0022-202X(21)01237-9. [Epub ahead of print]
      Vitiligo shows an insufficient response to current therapies, largely due to T lymphocyte dysfunction, abnormal inflammatory activation, and excessive oxidative stress in lesions. Cold atmospheric plasma (CAP) possesses pleiotropic anti-oxidant and anti-inflammatory properties and may offer an improvement to current treatment options. In this study, the efficacy and safety of CAP was investigated in a mouse model of vitiligo and a randomized and controlled trial of patients with active focal vitiligo. Topical treatment of vitiligo-like lesions on mouse dorsal skin by CAP restored the distribution of melanin in skin biopsies. In addition, CAP treatment reduced the infiltration of CD11c+ dendritic cells, CD3+ T cells, and CD8+ T cells; inhibited the release of chemokine (C-X-C motif) ligand 10 and cytokine interferon-γ; and enhanced cellular resistance to oxidative stress and excessive immune response by enhancing the expression of the transcription factor Nrf2 and attenuating the activity of inducible nitric oxide synthase. In a randomized and controlled trial, CAP treatment achieved partial and complete repigmentation in 80% and 20% of vitiligo lesions, respectively, without hyperpigmentation in surrounding areas or other adverse events during the treatment period and its follow-up period. In conclusion, CAP offers a promising option for the management of vitiligo.
  38. J Eur Acad Dermatol Venereol. 2021 May 27.
      Albinism is a worldwide genetic disorder caused by mutations in at least 20 genes, identified to date, that affect melanin production or transport in the skin, hair and eyes. Patients present with variable degrees of diffuse muco-cutaneous and adnexal hypopigmentation, as well as ocular features including nystagmus, misrouting of optic nerves and foveal hypoplasia. Less often, albinism is associated with blood, immunological, pulmonary, digestive and/or neurological anomalies. Clinical and molecular characterizations are essential in preventing potential complications. Disease-causing mutations remain unknown for about 25% of patients with albinism. These guidelines have been developed for the diagnosis and management of syndromic and non-syndromic forms of albinism, based on a systematic review of the scientific literature. These guidelines comprise clinical and molecular characterization, diagnosis, therapeutic approach and management.