Melanoma

Optimized protocol for immunophenotyping of melanoma and tumor-bearing skin from mouse

While isolating immune cells from spleens and lungs is routinely achieved using flow cytometry, it is challenging to isolate viable immune cells from skin. Here, we describe a step-by-step protocol for skin digestion using a murine melanoma model, which is amenable for detection of low abundant immune cell populations including group 2 innate lymphoid cells.

Up-regulation of KISS1 as a novel target of Let-7i in melanoma serves as a potential suppressor of migration and proliferation in vitro

Melanoma is a kind of skin cancer that is begun by the alteration of melanocytes. miRNAs are small non-coding RNA molecules that regulate a variety of biological processes. KISS1, the metastasis-suppressor gene, encodes kisspeptins which inhibits migration and proliferation of cancers. This study was aimed to determine the role of Let-7i and KISS1 in melanoma cell migration and proliferation. At first, the expression of Let-7i and KISS1 was determined in patients with melanoma. In the in vitro part of the study, Let-7i mimics were transfected and the impact of its restoration on target gene expression, proliferation, migration and apoptosis of SK-MEL-3 melanoma cell line was assessed by real-time PCR and Western blotting, MTT assay, wound-healing assay and flow cytometry, respectively. Besides, KISS1 inhibitor siRNA alone and along with Let-7i was transfected to determine their probable correlation. The results revealed that either Let-7i or KISS1 were down-regulated in patients with melanoma. The results obtained from the in vitro part of the study revealed that restoration of Let-7i reduced the expression of metastasis- and proliferation-related target genes. Moreover, it was revealed that up-regulation of Let-7i attenuated migration and proliferation capability of SK-MEL-3 cells. Besides, it was demonstrated that Let-7i restoration induced apoptosis in melanoma cells. More importantly, the KISS1 inhibitor caused a prominent cell migration and proliferation, attenuated by Let-7i re-expression. To sum up, the present study revealed the impressive role of Let-7i restoration along with its correlation with KISS1 on melanoma carcinogenicity which may be applicable in future in vivo studies.

LRG1 Promotes Metastatic Dissemination of Melanoma through Regulating EGFR/STAT3 Signalling

Although less common, melanoma is the deadliest form of skin cancer largely due to its highly metastatic nature. Currently, there are limited treatment options for metastatic melanoma and many of them could cause serious side effects. A better understanding of the molecular mechanisms underlying the complex disease pathophysiology of metastatic melanoma may lead to the identification of novel therapeutic targets and facilitate the development of targeted therapeutics. In this study, we investigated the role of leucine-rich α-2-glycoprotein 1 (LRG1) in melanoma development and progression. We first established the association between LRG1 and melanoma in both human patient biopsies and mouse melanoma cell lines and revealed a significant induction of LRG1 expression in metastatic melanoma cells. We then showed no change in tumour cell growth, proliferation, and angiogenesis in the absence of the host Lrg1. On the other hand, there was reduced melanoma cell metastasis to the lungs in Lrg1-deficient mice. This observation was supported by the promoting effect of LRG1 in melanoma cell migration, invasion, and adhesion. Mechanistically, LRG1 mediates melanoma cell invasiveness in an EGFR/STAT3-dependent manner. Taken together, our studies provided compelling evidence that LRG1 is required for melanoma metastasis but not growth. Targeting LRG1 may offer an alternative strategy to control malignant melanoma.

Location, location, location: Melanoma cells "living at the edge"

Abnormal cell migration and invasion underlie metastatic dissemination, one of the major challenges for cancer treatment. Melanoma is one of the deadliest and most aggressive forms of skin cancer due in part to its migratory and metastatic potential. Cancer cells use a variety of migratory strategies regulated by cytoskeletal remodelling. In particular, we discuss the importance of amoeboid invasive melanoma strategies, since they have been identified at the edge of human melanomas. We hypothesize that the presence of amoeboid melanoma cells will favour tumor progression since they are invasive and metastatic; they support immunosuppression; they harbour cancer stem cell properties and they are involved in therapy resistance. The Rho-ROCK-Myosin II pathway is key to maintain amoeboid melanoma invasion but this pathway is further regulated by pro-tumorigenic/pro-metastatic/pro-survival signalling pathways such as JAK-STAT3, TGFβ-SMAD, NF-κB, Wnt11/5-FDZ7 and BRAF^V600E -MEK-ERK. These pathways support amoeboid behaviour and are actionable in the clinic. After melanoma wide surgical margin removal, we propose that possible remaining melanoma cells should be eradicated using anti-amoeboid therapies.

Cytoplasmic CK1ε Protein Expression Is Correlated With Distant Metastasis and Survival in Patients With Melanoma

BACKGROUND/AIM

Casein kinase 1 epsilon (CK1ε) is a member of the casein kinase 1 family, which includes highly conserved and ubiquitous serine/threonine protein kinases. Recent research has revealed that CK1ε plays an important role in a variety of human cancer types; however, its role in human melanoma remains unclear. The aim of this study was to elucidate the clinical role of CK1ε in patients with melanoma.

PATIENTS AND METHODS

Samples from 34 patients with melanoma were analyzed by immunohistochemical staining. Formalin-fixed paraffin-embedded tissue microarrays were also examined by two histopathologists to assess CK1ε protein expression in humans.

RESULTS

Cytoplasmic CK1ε protein expression was significantly lower in tumor tissue than in normal tissue. Lack of cytoplasmic CK1ε protein was significantly correlated with distant metastasis (p=0.022) and poorer survival (p=0.030). However, Kaplan-Meier survival analysis revealed that elevated expression of cytoplasmic CK1ε protein was not significantly associated with the overall survival of patients with melanoma. Univariate and multivariate analyses demonstrated that lack of cytoplasmic CK1ε protein expression was related to distant metastasis (p<0.001 and p=0.004), showing that CK1ε was a prognostic factor.

CONCLUSION

CK1ε protein expression might serve as a prognostic indicator in the treatment of patients with melanoma.

Bergamottin Induces DNA Damage and Inhibits Malignant Progression in Melanoma by Modulating miR-145/Cyclin D1 Axis

Background

Melanoma is a prevalent skin cancer with the high rate of metastasis and mortality, affecting the increasing number of people worldwide. Bergamottin (BGM) is a natural furanocoumarin derived from grapefruits and presents the potential anti-cancer activity in several tumor models. However, the role of BGM in the development of melanoma remains unclear. Here, we aimed to explore the effect of BGM on the DNA damage and progression of melanoma.

Methods

The effect of BGM on the melanoma progression was analyzed by CCK-8 assays, colony formation assays, transwell assays, Annexin V-FITC Apoptosis Detection Kit, cell-cycle analysis, in vivo tumorigenicity analysis. The mechanism investigation was performed using luciferase reporter gene assays, qPCR assays, and Western blot analysis.

Results

We identified that BGM repressed cell proliferation, migration, and invasion of melanoma cells. BGM induced cell cycle arrest at the G0/G1 phase and enhanced apoptosis of melanoma cells. The DNA damage in the melanoma cells was stimulated by the BGM treatment. Meanwhile, BGM was able to up-regulate the expression of miR-145 and miR-145 targeted Cyclin D1 in the melanoma cells. Furthermore, BGM inhibited the progression of melanoma by targeting miR-145/Cyclin D1 axis in vitro. BGM attenuated the tumor growth of melanoma in vivo.

Conclusion

Thus, we conclude that BGM induces DNA damage and inhibits tumor progression in melanoma by modulating the miR-145/Cyclin D1 axis. Our finding provides new insights into the mechanism by which BGM modulates the development of melanoma. BGM may be applied as a potential anti-tumor candidate for the clinical treatment of melanoma.

Biomarkers for Diagnosis, Prognosis and Response to Immunotherapy in Melanoma

Cutaneous Melanoma classification is constantly looking for specific and sensitive biomarkers capable of having a positive effect on diagnosis, prognosis and risk assessment, eventually affecting clinical outcome. Classical morphological, immunohistochemical and the well-known BRAF and NRAS genetic biomarkers do not allow the correct categorization of patients, being melanoma conditioned by high genetic heterogeneity. At the same time, classic prognostic methods are unsatisfactory. Therefore, new advances in omics and high-throughput analytical techniques have enabled the identification of numerous possible biomarkers, but their potentiality needs to be validated and standardized in prospective studies. Melanoma is considered an immunogenic tumor, being the first form of cancer to take advantage of the clinical use of the immune-checkpoint blockers. However, as immunotherapy is effective only in a limited number of patients, biomarkers associated with different responses are essential to select the more promising therapeutic approach and maximize clinical benefits. In this review, we summarize the most utilized biomarkers for Cutaneous Melanoma diagnosis, focusing on new prognostic and predictive biomarkers mainly associated with immunotherapy.

Twenty-five practical recommendations in primary care dermoscopy

Dermoscopy in primary care enhances clinical diagnoses and allows for risk stratifications. We have compiled 25 recommendations from our experience of dermoscopy in a wide range of clinical settings. The aim of this study is to enhance the application of dermoscopy by primary care clinicians. For primary care physicians commencing dermoscopy, we recommend understanding the aims of dermoscopy, having adequate training, purchasing dermoscopes with polarised and unpolarised views, performing regular maintenance on the equipment, seeking consent, applying contact and close non-contact dermoscopy, maintaining sterility, knowing one algorithm well and learning the rules for special regions such as the face, acral regions and nails. For clinicians already applying dermoscopy, we recommend establishing a platform for storing and retrieving clinical and dermoscopic images; shooting as uncompressed files; applying high magnifications and in-camera improvisations; explaining dermoscopic images to patients and their families; applying toggling; applying scopes with small probes for obscured lesions and lesions in body creases; applying far, non-contact dermoscopy; performing skin manipulations before and during dermoscopy; practising selective dermoscopy if experienced enough; and being aware of compound lesions. For clinicians in academic practice for whom dermatology and dermoscopy are special interests, we recommend acquiring the best hardware available with separate setups for clinical photography and dermoscopy; obtaining oral or written consent from patients for taking and publishing recognisable images; applying extremely high magnifications in search of novel dermoscopic features that are clinically important; applying dermoscopy immediately after local anaesthesia; and further augmenting images to incorporate messages beyond words to readers.

microRNAs in the Regulation of Melanogenesis

Melanogenesis is the process leading to the synthesis of melanin, the main substance that influences skin color and plays a pivotal role against UV damage. Altered melanogenesis is observed in several pigmentation disorders. Melanogenesis occurs in specialized cells called melanocytes, physically and functionally related by means of autocrine and paracrine interplay to other skin cell types. Several external and internal factors control melanin biosynthesis and operate through different intracellular signaling pathways, which finally leads to the regulation of microphthalmia-associated transcription factor (MITF), the key transcription factor involved in melanogenesis and the expression of the main melanogenic enzymes, including TYR, TYRP-1, and TYRP-2. Epigenetic factors, including microRNAs (miRNAs), are involved in melanogenesis regulation. miRNAs are small, single-stranded, non-coding RNAs, of approximately 22 nucleotides in length, which control cell behavior by regulating gene expression, mainly by binding the 3′ untranslated region (3′-UTR) of target mRNAs. This review collects data on the miRNAs involved in melanogenesis and how these miRNAs can modulate target gene expression. Bringing to light the biological function of miRNAs could lead to a wider understanding of epigenetic melanogenesis regulation and its dysregulation. This knowledge may constitute the basis for developing innovative treatment approaches for pigmentation dysregulation.

Nuciferine Inhibits Skin Cutaneous Melanoma Cell Growth by Suppressing TLR4/NF-κB Signaling

BACKGROUND

Melanoma causes more than 80% of deaths from all dermatologic cancers. Hence, screening and identifying effective compounds to inhibit the growth of melanoma have crucial importance in basic and clinical treatment.

METHODS

High throughput screening was performed to screen and identify compounds that have anti-melanoma ability. Melanoma cell and mouse allograft models were used to examine the anti-tumor effects of Nuciferine (NCFR). Western blot, qPCR, and lentivirus overexpression were applied to detect the activation of the TLR4/NF-κB signaling pathway.

RESULTS

NCFR administration significantly suppressed melanoma cell growth and tumor size by inhibiting the phosphorylation of p65. NCFR treatment also could suppress TNF-α-induced activation of NF-κB signaling. The anti-tumor effect of NCFR might be mediated by targeting Toll-like receptors 4.

CONCLUSION

NCFR inhibits melanoma cell growth and suppresses tumor size, which provides potential therapeutic strategies for melanoma treatment.

Rapid Noninvasive Skin Monitoring by Surface Mass Recording and Data Learning

Skin problems are often overlooked due to a lack of robust and patient-friendly monitoring tools. Herein, we report a rapid, noninvasive, and high-throughput analytical chemical methodology, aiming at real-time monitoring of skin conditions and early detection of skin disorders. Within this methodology, adhesive sampling and laser desorption ionization mass spectrometry are coordinated to record skin surface molecular mass in minutes. Automated result interpretation is achieved by data learning, using similarity scoring and machine learning algorithms. Feasibility of the methodology has been demonstrated after testing a total of 117 healthy, benign-disordered, or malignant-disordered skins. Remarkably, skin malignancy, using melanoma as a proof of concept, was detected with 100% accuracy already at early stages when the lesions were submillimeter-sized, far beyond the detection limit of most existing noninvasive diagnosis tools. Moreover, the malignancy development over time has also been monitored successfully, showing the potential to predict skin disorder progression. Capable of detecting skin alterations at the molecular level in a nonsurgical and time-saving manner, this analytical chemistry platform is promising to build personalized skin care.

A Review of Epidemiology and Cancer Biology of Malignant Melanoma

Malignant melanoma is a neoplasm originating in the melanocytes in the skin. Although malignant melanoma is the third most common cutaneous cancer, it is recognized as the main cause of skin cancer-related mortality, and its incidence is rising. The natural history of malignant melanoma involves an inconsistent and insidious skin cancer with great metastatic potential. Increased ultra-violet (UV) skin exposure is undoubtedly the greatest risk factor for developing cutaneous melanoma; however, a plethora of risk factors are now recognized as causative. Moreover, modern oncology now considers melanoma proliferation a complex, multifactorial process with a combination of genetic, epigenetic, and environmental factors all known to be contributory to tumorgenesis. Herein, we wish to outline the epidemiological, molecular, and biological processes responsible for driving malignant melanoma proliferation.

Melanoma Progression under Obesity: Focus on Adipokines

Simple Summary

Obesity is a rapidly growing public health problem and the reason for numerous diseases in the human body, including cancer. This article reviews the current knowledge of the effect of molecules secreted by adipose tissue-adipokines on melanoma progression. We also discuss the role of these factors as markers of incidence, metastasis, and melanoma patient survival. Understanding the functions of adipokines will lead to knowledge of whether and how obesity promotes melanoma growth.

Abstract

Obesity is a growing problem in the world and is one of the risk factors of various cancers. Among these cancers is melanoma, which accounts for the majority of skin tumor deaths. Current studies are looking for a correlation between obesity and melanoma. They suspect that a potential cause of its development is connected to the biology of adipokines, active molecules secreted by adipose tissue. Under physiological conditions, adipokines control many processes, including lipid and glucose homeostasis, insulin sensitivity, angiogenesis, and inflammations. However, when there is an increased amount of fat in the body, their secretion is dysregulated. This article reviews the current knowledge of the effect of adipokines on melanoma growth. This work focuses on the molecular pathways by which adipose tissue secreted molecules modify the angiogenesis, migration, invasion, proliferation, and death of melanoma cells. We also discuss the role of these factors as markers of incidence, metastasis, and melanoma patient survival. Understanding the functions of adipokines will lead to knowledge of whether and how obesity promotes melanoma growth. Further studies may contribute to the innovations of therapies and the use of adipokines as predictive and/or prognostic biomarkers.

The Role of Senescent Cells in Acquired Drug Resistance and Secondary Cancer in BRAFi-Treated Melanoma

BRAF is the most common gene mutated in malignant melanoma, and predominately it is a missense mutation of codon 600 in the kinase domain. This oncogenic BRAF missense mutation results in constitutive activation of the mitogen-activate protein kinase (MAPK) pro-survival pathway. Several BRAF inhibitors (BRAFi) have been developed to specifically inhibit BRAFV600 mutations that improve melanoma survival, but resistance and secondary cancer often occur. Causal mechanisms of BRAFi-induced secondary cancer and resistance have been identified through upregulation of MAPK and alternate pro-survival pathways. In addition, overriding of cellular senescence is observed throughout the progression of disease from benign nevi to malignant melanoma. In this review, we discuss melanoma BRAF mutations, the genetic mechanism of BRAFi resistance, and the evidence supporting the role of senescent cells in melanoma disease progression, drug resistance and secondary cancer. We further highlight the potential benefit of targeting senescent cells with senotherapeutics as adjuvant therapy in combating melanoma.

Progress in tumour-targeted drug delivery based on cell-penetrating peptides

Since the discovery of cell-penetrating peptides (CPP) in the 1980s, they have played a unique role in various fields owing to their excellent and unique cell membrane penetration function. In particular, in the treatment of tumours, CPPS have been used to deliver several types of 'cargos' to cancer cells. To address the insufficient targeting ability, non-selectivity, and blood instability, activatable cell-penetrating peptides, which can achieve targeted drug delivery in tumour treatment, enhance curative effects, and reduce toxicity have been developed. This study reviews the application of different cell-penetrating peptides in tumour-targeted delivery, overcoming multidrug resistance, organelle targeting, tumour imaging, and diagnosis, and summarises the different mechanisms of activatable cell-penetrating peptides in detail.

Cannabinoid Receptor Type-2 in B Cells Is Associated with Tumor Immunity in Melanoma

Simple Summary

In this study we investigated the role of cannabinoid receptor 2 (CB2R) on immune cells in melanoma and found significantly improved overall survival in patients with high intra-tumoral CB2R gene expression. In human melanoma, CB2R is predominantly expressed in B cells, as shown using a previously published single-cell RNA sequencing (scRNA-seq) dataset and by performing RNAscope. In a murine melanoma model, tumor growth was enhanced in CB2R-deficient mice. In-depth analysis of tumor-infiltrating lymphocytes using scRNA-seq showed less differentiated B cells in CB2R-deficient tumors, favoring the induction of regulatory T cells (T_reg) and an immunosuppressive tumor microenvironment. Taken together, these data indicate a central role of CB2R on B cells in regulating tumor immunity. These results contribute to the understanding of the role of CB2R in tumor immunity and facilitate the development of new CB2R-targeted anti-cancer drugs.

Abstract

Agents targeting the endocannabinoid system (ECS) have gained attention as potential cancer treatments. Given recent evidence that cannabinoid receptor 2 (CB2R) regulates lymphocyte development and inflammation, we performed studies on CB2R in the immune response against melanoma. Analysis of The Cancer Genome Atlas (TCGA) data revealed a strong positive correlation between CB2R expression and survival, as well as B cell infiltration in human melanoma. In a murine melanoma model, CB2R expression reduced the growth of melanoma as well as the B cell frequencies in the tumor microenvironment (TME), compared to CB2R-deficient mice. In depth analysis of tumor-infiltrating B cells using single-cell RNA sequencing suggested a less differentiated phenotype in tumors from Cb2r^−/− mice. Thus, in this study, we demonstrate for the first time a protective, B cell-mediated role of CB2R in melanoma. This gained insight might assist in the development of novel, CB2R-targeted cancer therapies.

PLEKHA4 Promotes Wnt/β-Catenin Signaling-Mediated G1-S Transition and Proliferation in Melanoma

Despite recent promising advances in targeted therapies and immunotherapies, patients with melanoma incur substantial mortality. In particular, inhibitors targeting BRAF-mutant melanoma can lead to resistance, and no targeted therapies exist for NRAS-mutant melanoma, motivating the search for additional therapeutic targets and vulnerable pathways. Here we identify a regulator of Wnt/β-catenin signaling, PLEKHA4, as a factor required for melanoma proliferation and survival. PLEKHA4 knockdown in vitro decreased Dishevelled levels, attenuated Wnt/β-catenin signaling, and blocked progression through the G1-S cell-cycle transition. In mouse xenograft and allograft models, inducible PLEKHA4 knockdown attenuated tumor growth in BRAF- and NRAS-mutant melanomas and exhibited an additive effect with the clinically used inhibitor encorafenib in a BRAF-mutant model. As an E3 ubiquitin ligase regulator with both lipid- and protein-binding partners, PLEKHA4 presents several opportunities for targeting with small molecules. Our work identifies PLEKHA4 as a promising drug target for melanoma and clarifies a controversial role for Wnt/β-catenin signaling in the control of melanoma proliferation. SIGNIFICANCE: This study establishes that melanoma cell proliferation requires the protein PLEKHA4 to promote pathologic Wnt signaling for proliferation, highlighting PLEKHA4 inhibition as a new avenue for the development of targeted therapies.

Hypoxia and Extracellular Acidification as Drivers of Melanoma Progression and Drug Resistance

Hypoxia and elevated extracellular acidification are prevalent features of solid tumors and they are often shown to facilitate cancer progression and drug resistance. In this review, we have compiled recent and most relevant research pertaining to the role of hypoxia and acidification in melanoma growth, invasiveness, and response to therapy. Melanoma represents a highly aggressive and heterogeneous type of skin cancer. Currently employed treatments, including BRAF V600E inhibitors and immune therapy, often are not effective due to a rapidly developing drug resistance. A variety of intracellular mechanisms impeding the treatment were discovered. However, the tumor microenvironment encompassing stromal and immune cells, extracellular matrix, and physicochemical conditions such as oxygen level or acidity, may also influence the therapy effectiveness. Hypoxia and acidification are able to reprogram the metabolism of melanoma cells, enhance their survival and invasiveness, as well as promote the immunosuppressive environment. For this reason, these physicochemical features of the melanoma niche and signaling pathways related to them emerge as potential therapeutic targets.

TBX3 Promotes Melanoma Migration by Transcriptional Activation of ID1, which Prevents Activation of E-Cadherin by MITF

In melanoma, a phenotype switch from proliferation to invasion underpins metastasis, the major cause of melanoma-associated death. The transition from radial to vertical growth phase (invasive) melanoma is characterized by downregulation of both E-cadherin (CDH1) and MITF and upregulation of the key cancer-associated gene TBX3 and the phosphatidylinositol 3 kinase signaling pathway. Yet, whether and how these diverse events are linked remains poorly understood. Here, we show that TBX3 directly promotes expression of ID1, a dominant-negative regulator of basic helix-loop-helix transcription factors, and that ID1 decreases MITF binding and upregulation of CDH1. Significantly, we show that TBX3 activation of ID1 is necessary for TBX3 to enhance melanoma cell migration, and the mechanistic links between TBX3, ID1, MITF, and invasion revealed here are reflected in their expression in human melanomas. Our results reveal that melanoma migration is promoted through a TBX3-ID1-MITF-E-cadherin axis and that ID1-mediated repression of MITF activity may reinforce maintenance of an MITF^Low phenotype associated with disease progression and therapy resistance.

Systemic Therapy of Metastatic Melanoma: On the Road to Cure

This decade has brought significant survival improvement in patients with metastatic melanoma with targeted therapies and immunotherapies. As our understanding of the mechanisms of action of these therapeutics evolves, even more impressive therapeutic success is being achieved through various combination strategies, including combinations of different immunotherapies as well as with other modalities. This review summarizes prospectively and retrospectively generated clinical evidence on modern melanoma therapy, focusing on immunotherapy and targeted therapy with BRAF kinase inhibitors and MEK kinase inhibitors (BRAF/MEK inhibitors), including recent data presented at major conference meetings. The combination of the anti-PD-1 directed monoclonal antibody nivolumab and of the CTLA-4 antagonist ipilimumab achieves unprecedented 5-year overall survival (OS) rates above 50%; however, toxicity is high. For PD-1 monotherapy (nivolumab or pembrolizumab), toxicities are in general well manageable. Today, novel combinations of such immune checkpoint inhibitors (ICIs) are under investigation, for example with cytokines and oncolytic viruses (i.e., pegylated interleukin-2, talimogene laherparepvec). Furthermore, current studies investigate the combined or sequential use of ICIs plus BRAF/MEK inhibitors. Several studies focus particularly on poor prognosis patients, as e.g., on anti-PD-1 refractory melanoma, patients with brain metastases, or uveal melanoma. It is hoped, on the road to cure, that these new approaches further improve long term survival in patients with advanced or metastatic melanoma.

Emodin Suppresses the Migration and Invasion of Melanoma Cells

Emodin (1,3,8-trihydroxy-6-methylanthraquinone), as an active ingredient in rhubarb roots and rhizomes, has been reported to possess various pharmacological properties including anti-tumor effects. Recent studies have confirmed that emodin inhibited cell proliferation and induced apoptosis of cancer cells. However, the inhibitory effect of emodin on the migration and invasion of melanoma cells and its underlying mechanism are still unclear. In the study, we observed the impercipient effects of emodin in B16F10 and A375 melanoma cells with strong metastatic abilities, focusing on the functions and mechanisms of migration and invasion of B16F10 and A375 melanoma cells. Cell counting kit-8 (CCK-8), colony formation test and Annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) staining tests confirmed that emodin possessed anti-proliferative and pro-apoptotic activities in B16F10 and A375 cells. The inhibitory effects on the migration and invasion of B16F10 and A375 cells were proved by wound healing assay and Transwell methods. Moreover, immunofluorescence assay approved the decrease in protein expression of matrix metalloproteinas (MMP)-2/-9 by emodin, and Western blot analyses revealed that emodin could increase the Bax/Bcl-2 ratio and inhibit the MMP-2/-9 protein expression and Wnt/β-catenin pathway in a dose-depended manner. BML-284, as an agonist of Wnt/β-catenin signaling pathway, reversed the effects of emodin on cell growth, migration and invasion in B16F10 cells. These findings may suggest that emodin treatment can be a promising therapeutic strategy for melanoma with highly metastatic abilities.

Integrin-α9β1 as a Novel Therapeutic Target for Refractory Diseases: Recent Progress and Insights

Integrins refer to heterodimers consisting of subunits α and β. They serve as receptors on cell membranes and interact with extracellular ligands to mediate intracellular molecular signals. One of the least-studied members of the integrin family is integrin-α9β1, which is widely distributed in various human tissues and organs. Integrin-α9β1 regulates the physiological state of cells through a variety of complex signaling pathways to participate in the specific pathological processes of some intractable diseases. In recent years, an increasing amount of research has focused on the role of α9β1 in the molecular mechanisms of different refractory diseases and its promising potential as a therapeutic target. Accordingly, this review introduces and summarizes recent research related to integrin-α9β1, describes the synergistic functions of α9β1 and its corresponding ligands in cancer, autoimmune diseases, nerve injury and thrombosis and, more importantly, highlights the potential of α9β1 as a distinctive target for the treatment of these intractable diseases.

Benzamide derivative radiotracers targeting melanin for melanoma imaging and therapy: Preclinical/clinical development and combination with other treatments

Cutaneous melanoma arises from proliferating melanocytes, cells specialized in the production of melanin. This property means melanin can be considered as a target for monitoring melanoma patients using nuclear imaging or targeted radionuclide therapy (TRT). Since the 1970s, many researchers have shown that specific molecules can interfere with melanin. This paper reviews some such molecules: benzamide structures improved to increase their pharmacokinetics for imaging or TRT. We first describe the characteristics and biosynthesis of melanin, and the main features of melanin tracers. The second part summarizes the preclinical and corresponding clinical studies on imaging. The last section presents TRT results from ongoing protocols and discusses combinations with other therapies as an opportunity for melanoma non-responders or patients resistant to treatments.

Anti-Tumoral and Anti-Angiogenic Effects of Low-Diluted Phenacetinum on Melanoma

Melanoma is the most aggressive form of skin cancer and the most rapidly expanding cancer in terms of worldwide incidence. If primary cutaneous melanoma is mostly treated with a curative wide local excision, malignant melanoma has a poor prognosis and needs other therapeutic approaches. Angiogenesis is a normal physiological process essential in growth and development, but it also plays a crucial role in crossing from benign to advanced state in cancer. In melanoma progression, angiogenesis is widely involved during the vertical growth phase. Currently, no anti-angiogenic agents are efficient on their own, and combination of treatments will probably be the key to success. In the past, phenacetin was used as an analgesic to relieve pain, causing side effects at large dose and tumor-inducing in humans and animals. By contrast, Phenacetinum low-dilution is often used in skin febrile exanthema, patches profusely scattered on limbs, headache, or flushed face without side effects. Herein are described the in vitro, in vivo, and ex vivo anti-angiogenic and anti-tumoral potentials of Phenacetinum low-dilution in a B16F1 tumor model and endothelial cells. We demonstrate that low-diluted Phenacetinum inhibits in vivo tumor growth and tumor vascularization and thus increases the survival time of B16F1 melanoma induced-C57BL/6 mice. Moreover, Phenacetinum modulates the lung metastasis in a B16F10 induced model. Ex vivo and in vitro, we evidence that low-diluted Phenacetinum inhibits the migration and the recruitment of endothelial cells and leads to an imbalance in the pro-tumoral macrophages and to a structural malformation of the vascular network. All together these results demonstrate highly hopeful anti-tumoral, anti-metastatic, and anti-angiogenic effects of Phenacetinum low-dilution on melanoma. Continued studies are needed to preclinically validate Phenacetinum low-dilution as a complementary or therapeutic strategy for melanoma treatment.

Unemployment and Health-Related Quality of Life in Melanoma Patients During the COVID-19 Pandemic

The outbreak of coronavirus disease-2019 (COVID-19) ineluctably caused social distancing and unemployment, which may bring additional health risks for patients with cancer. To investigate the association of the pandemic-related impacts with the health-related quality of life (HRQoL) among patients with melanoma during the COVID-19 pandemic, we conducted a cross-sectional study among Chinese patients with melanoma. A self-administered online questionnaire was distributed to melanoma patients through social media. Demographic and clinical data, and pandemic-related impacts (unemployment and income loss) were collected. HRQoL was determined by the Functional Assessment of Cancer Therapy-General (FACT-G) and its disease-specific module (the melanoma subscale, MS). A total of 135 patients with melanoma completed the study. The mean age of the patients was 55.8 ± 14.2 years, 48.1% (65/135) were male, and 17.04% (34/135) were unemployed since the epidemic. Unemployment of the patients and their family members and income loss were significantly associated with a lower FACT-G score, while the MS score was associated with the unemployment of the patients' family members. Our findings suggested that unemployment is associated with impaired HRQoL in melanoma patients during the COVID-19 epidemic.

The Identification and Validation of a Robust Immune-Associated Gene Signature in Cutaneous Melanoma

BACKGROUND

Cutaneous melanoma is defined as one of the most aggressive skin tumors in the world. An increasing body of evidence suggested an indispensable association between immune-associated gene (IAG) signature and melanoma. This article is aimed at formulating an IAG signature to estimate prognosis of melanoma.

METHODS

434 melanoma patients were extracted from The Cancer Genome Atlas (TCGA) database, and 1811 IAGs were downloaded from the ImmPort database in our retrospective study. The Cox regression analysis and LASSO regression analysis were utilized to establish a prognostic IAG signature. The Kaplan-Meier (KM) survival analysis was performed, and the time-dependent receiver operating characteristic curve (ROC) analysis was further applied to assess the predictive value. Besides, the propensity score algorithm was utilized to balance the confounding clinical factors between the high- and low-risk groups.

RESULTS

A total of six prognostic IAGs comprising of INHA, NDRG1, IFITM1, LHB, GBP2, and CCL8 were eventually filtered out. According to the KM survival analysis, the results displayed a shorter overall survival (OS) in the high-risk group compared to the low-risk group. In the multivariate Cox model, the gene signature was testified as a remarkable prognostic factor (HR = 45.423, P < 0.001). Additionally, the ROC curve analyses were performed which demonstrated our IAG signature was superior to four known biomarkers mentioned in the study. Moreover, the IAG signature was significantly related to immunotherapy-related biomarkers.

CONCLUSION

Our study demonstrated that the six IAG signature played a critical role in the prognosis and immunotherapy of melanoma, which might help clinicians predict patients' survival and provide individualized treatment.

Immunohistochemistry analysis reveals lysyl oxidase-like 3 as a novel prognostic marker for primary melanoma

Lysyl oxidase-like 3 (LOXL3) is an extracellular enzyme involved in the synthesis of collagen and elastin, and it has been reported to promote melanoma cell proliferation and invasion in vitro. However, the expression level of LOXL3 at different stages of melanocytic lesions and the role of LOXL3 in melanoma pathogenesis remain unknown. Immunohistochemical staining of LOXL3 in a tissue microarray of 373 biopsies at different melanocytic stages was conducted. The correlation between LOXL3 expression and patient survival was examined using Kaplan-Meier survival analysis. Univariate and multivariate Cox regression analyses were conducted to study the hazard ratios. The tissue microarray study revealed that stronger expression of LOXL3 protein was found at more advanced melanocytic stages (P < 0.0001; χ2 test). Increased LOXL3 expression was associated with enhanced tumor thickness and mitosis. Survival analysis showed significantly worsened prognosis in primary melanoma patients when the LOXL3 expression level was higher (P = 0.043; log-rank test). Multivariate Cox regression analysis further showed that LOXL3 expression is a prognostic factor for primary melanoma patient survival (P = 0.04). LOXL3 expression is positively correlated with tumor progression and invasion, and its overexpression is associated with worse prognosis of primary melanoma patients. LOXL3 can serve as a prognostic marker to help identify primary melanoma patients at higher risks of death.

The BH3 mimetic (±) gossypol induces ROS-independent apoptosis and mitochondrial dysfunction in human A375 melanoma cells in vitro

A major challenge in current cancer therapy is still the treatment of metastatic melanomas of the skin. BH3 mimetics represent a novel group of substances inducing apoptosis. In this study, we investigated the cytotoxic effect of (±) gossypol (GP), a natural compound from cotton seed, on A375 melanoma cells and the underlying biochemical mechanisms. To prevent undesired side effects due to toxicity on normal (healthy) cells, concentrations only toxic for tumor cells have been elaborated. Viability assays were performed to determine the cytotoxicity of GP in A375 melanoma and normal (healthy) cells. For the majority of experiments, a concentration of 2.5 µM GP was used resulting in a ROS-independent but caspase-dependent cell death of A375 melanoma cells. At this level, GP was non-toxic for normal human epidermal melanocytes. GP has a very short half-life, however, it was demonstrated that only the “parent” compound and not decomposition products are responsible for the cytotoxic effect in A375 melanoma cells. GP significantly decreased mitochondrial membrane potential accompanied by a Drp1-dependent loss of mitochondrial integrity (fragmentation) in tumor cells. Taken together, GP induced a ROS-independent intrinsic apoptosis leading to the conclusion that within a specific concentration range, GP may work as effective anticancer drug without harmful side effects.

Synthesis of Hydroxylated Biphenyl Derivatives Bearing an α,β-Unsaturated Ketone as a Lead Structure for the Development of Drug Candidates against Malignant Melanoma

A small collection of C₂ -symmetric hydroxylated biphenyl derivatives featuring an α,β-unsaturated ketone as a lead structure was prepared, and the capacity of these compounds to act as antiproliferative agents against four human malignant melanoma cell lines was assayed. The prodrug approach was applied in order to improve the delivery of compounds into the cell by modulation of the phenolic hydroxy protecting group. The hydroxylated biphenyl structure bearing an α,β-unsaturated ketone and a phenolic-O-prenylated chain was found to facilitate the delivery of the molecule and interactions with biological targets. Four compounds showed antiproliferative activity resulting in IC₅₀ values in the range of 1.2 to 2.8 μM.

ARNT deficiency represses pyruvate dehydrogenase kinase 1 to trigger ROS production and melanoma metastasis

The metabolic changes in melanoma cells that are required for tumor metastasis have not been fully elucidated. In this study, we show that the increase in glucose uptake and mitochondrial oxidative phosphorylation confers metastatic ability as a result of aryl hydrocarbon receptor nuclear translocator (ARNT) deficiency. In clinical tissue specimens, increased ARNT, pyruvate dehydrogenase kinase 1 (PDK1), and NAD(P)H quinine oxidoreductase-1 (NQO1) was observed in benign nevi, whereas lower expression was observed in melanoma. The depletion of ARNT dramatically repressed PDK1 and NQO1 expression, which resulted in an increase of ROS levels. The elimination of ROS using N-acetylcysteine (NAC) and inhibition of oxidative phosphorylation using carbonyl cyanide m-chlorophenyl hydrazone (CCCP) and rotenone inhibited the ARNT and PDK1 deficiency-induced cell migration and invasion. In addition, ARNT deficiency in tumor cells manipulated the glycolytic pathway through enhancement of the glucose uptake rate, which reduced glucose dependence. Intriguingly, CCCP and NAC dramatically inhibited ARNT and PDK1 deficiency-induced tumor cell extravasation in mouse models. Our work demonstrates that downregulation of ARNT and PDK1 expression serves as a prognosticator, which confers metastatic potential as the metastasizing cells depend on metabolic changes.

Novel Functions of CD147 in the Mitochondria Exacerbates Melanoma Metastasis

Melanoma is an aggressive form of skin cancer characterized by rapid invasion and metastasis. CD147 is known to be functioning in cell invasion. In this study, we showed that CD147 was translocated from the cell membrane to the mitochondria in advanced melanoma. Melanoma patients with CD147 localized to the mitochondria confer a worse prognosis. The mitochondrial CD147 levels are correlated with the invasion potential of various melanoma cell lines as well as mitochondrial energy metabolism. Depletion of CD147 decreased the activity of mitochondrial complex V. STRING analysis for protein-protein interaction networks (PPIN) in CD147-depleted melanoma cells showed that mitochondrial proteins HSP60 and ATP5B, a subunit of mitochondrial complex V, were node proteins. HSP60 upregulation was correlated with a worse prognosis of melanoma patients. Co-immunoprecipitation (Co-IP) assay indicates that CD147 interacts with HSP60. These data suggested that mitochondrial CD147 may prompt HSP60 to activate ATP5B, thereby promoting the mitochondrial aerobic oxidation and the invasive abilities of melanoma cells. Correlation analysis of the data acquired from patients was helpful to draw a 5-year survival curve for patients who screened positive and negative for mitochondrial CD147. This study unravels the function of CD147 in tumor invasion and highlights it as a potential tumor therapeutic target.

A Fluorescent Gelatin Degradation Assay to Study Melanoma Breakdown of Extracellular Matrix

In order to protrude within a dense tissue, tumor cells have to develop the ability to digest the extracellular matrix (ECM). Melanoma cells, similarly to other types of tumor cells, form invadopodia, membranous invaginations rich in filamentous actin and several other proteins including matrix metalloproteinases (MMPs). MMPs degrade ECM structural proteins such as collagens, fibronectin, or laminin. Here we describe an assay that allows the detection of gelatinase activity exhibited by tumor cells under 2D conditions and methods to present obtained data in both a quantitative and a qualitative manner.

Use of Nanoparticles in Delivery of Nucleic Acids for Melanoma Treatment

Melanoma accounts for 4% of all skin cancer malignancies, with only 14% of diagnosed patients surviving for more than 5 years after diagnosis. Until now, there is no clear understanding of the detailed molecular contributors of melanoma pathogenesis. Accordingly, more research is needed to understand melanoma development and prognosis.All the treatment approaches that are currently applied have several significant limitations that prevent effective use in melanoma. One major limitation in the treatment of cancer is the acquisition of multidrug resistance (MDR). The MDR results in significant treatment failure and poor clinical outcomes in several cancers, including skin cancer. Treatment of melanoma is especially retarded by MDR. Despite the current advances in targeted and immune-mediated therapy, treatment arms of melanoma are severely limited and stand as a significant clinical challenge. Further, the poor pharmacokinetic profile of currently used chemotherapeutic agents is another reason for treatment failure. Therefore, more research is needed to develop novel drugs and carrier tools for more effective and targeted treatment.Nucleic acid therapy is based on nucleic acids or chemical compounds that are closely related, such as antisense oligonucleotides, aptamers, and small-interfering RNAs that are usually used in situations when a specific gene implicated in a disorder is deemed a therapeutically beneficial target for inhibition. However, the proper application for nucleic acid therapies is hampered by the development of an effective delivery system that can maintain their stability in the systemic circulation and enhance their uptake by the target cells. In this chapter, the prognosis of the different types of melanoma along with the currently used medications is highlighted, and the different types of nucleic acids along with the currently available nanoparticle systems for delivering these nucleic acids into melanoma cells are discussed. We also discuss recently conducted research on the use of different types of nanoparticles for nucleic acid delivery into melanoma cells and highlight the most significant outcomes.

Investigation of microRNA-10b values for the discrimination of metastasis due to melanoma

Background:

Melanoma is one of the most invasive cutaneous cancers with characteristics such as rapid progression and distant metastasis. The early diagnosis and staging of melanoma can help better manage the patients. The current study is aimed to assess the values of microRNA-10b (miRNA-10b) in the discrimination of metastatic melanomas.

Materials and Methods:

The current cross-sectional study has been conducted on forty patients diagnosed with melanoma since 2011. Cell culture of melanoma cell lines derived from the cancerous tissue, including WM115, BLM, K1735, WM793, and A375M, was cultured. In order to assess miRNA-10b levels, the real-time polymerase chain reaction was utilized. The absence (n = 20)/presence (n = 20) of metastasis was diagnosed with chest computed tomography or chest X-ray. The values of miRNA-10b for the discrimination of metastasis incidence were assessed.

Results:

The demographic characteristics, including age and gender of the metastatic and nonmetastatic patients, were similar (P > 0.05). The specimen cultures were positive for miRNA-10b in 14 (35%) of the metastatic cases versus 4 (20%) of the nonmetastatic ones (P = 0.004). The quantitative analysis of miR-2b revealed significantly higher levels in metastatic cases (−1.59 ± 1.13 in metastatic vs. −0.16 ± 0.67 in nonmetastatic cases; P = 0.001). The measured area under the curve for the value of miRNA-10b was 0.923 (P < 0.001; 95% confidence interval: 0.811–1) with sensitivity and specificity of 100% and 94.4%.

Conclusion:

Based on this study, metastatic melanoma was associated with elevated levels of miRNA-10b. This marker had the sensitivity and specificity of 100% and 94.4% for the discrimination of metastatic melanoma from nonmetastatic ones.

Therapeutic strategies and potential implications of silver nanoparticles in the management of skin cancer

Skin cancer (SC) is the most common carcinoma affecting 3 million people annually in the United States and millions of people worldwide. It is classified as melanoma SC (MSC) and non-melanoma SC (NMSC). NMSC represents approximately 80% of SC and includes squamous cell carcinoma and basal cell carcinoma. MSC, however, has a higher mortality rate than SC because of its ability to metastasize. SC is a major health problem in the United States with significant morbidity and mortality in the Caucasian population. Treatment options for SC include cryotherapy, excisional surgery, Mohs surgery, curettage and electrodessication, radiation therapy, photodynamic therapy, immunotherapy, and chemotherapy. Treatment is chosen based on the type of SC and the potential for side effects. Novel targeted therapies are being used with increased frequency for large tumors and for metastatic disease. A scoping literature search on PubMed, Google Scholar, and Cancer Registry websites revealed that traditional chemotherapeutic drugs have little effect against SC after the cancer has metastasized. Following an overview of SC biology, epidemiology, and treatment options, this review focuses on the mechanisms of advanced technologies that use silver nanoparticles in SC treatment regimens.

Human and mouse melanoma cells recapitulate an EMT-like program in response to mesenchymal stromal cells secretome

The mechanisms underlying the propensity of melanomas to metastasize are not completely understood. We hypothesized that melanoma cells are capable of promptly activating an epithelial-to-mesenchymal transition (EMT)-like profile in response to stroma-derived factors. Thus, we investigated the role of mesenchymal stromal cells (MSCs), a cell population considered as a precursor of tumor stroma, on the activation of an EMT-like profile and acquisition of metastatic traits in melanoma cells. After subcutaneous co-injection with mouse B16 melanoma cells, MSCs occupied perivascular sites within tumors and enhanced B16 metastasis to the lungs. In vitro, MSCs' secretome activated an EMT-like profile in B16 cells, reducing their avidity to fibronectin, and increasing their motility and invasiveness. These effects were abrogated upon blocking of MET phosphorylation in B16 cells using small molecule inhibitors. MSCs also activated an EMT-like profile in human melanoma cells from different stages of progression. Activation of EMT in human cells was associated with increased levels of p-STAT1 and p-STAT3. In conclusion, both mouse and human melanoma cells are equipped to activate an EMT-like program and acquire metastatic traits through the activation of distinct pathways by MSCs' secretome.

Circulating Melanoma-Derived Extracellular Vesicles: Impact on Melanoma Diagnosis, Progression Monitoring, and Treatment Response

Malignant melanoma, one of the most aggressive human malignancies, is responsible for 80% of skin cancer deaths. Whilst early detection of disease progression or metastasis can improve patient survival, this remains a challenge due to the lack of reliable biomarkers. Importantly, these clinical challenges are not unique to humans, as melanoma affects many other species, including companion animals, such as the dog and horse. Extracellular vesicles (EVs) are tiny nanoparticles involved in cell-to-cell communication. Several protein and genomic EV markers have been described in the literature, as well as a wide variety of methods for isolating EVs from body fluids. As such, they may be valuable biomarkers in cancer and may address some clinical challenges in the management melanoma. This review aimed to explore the translational applications of EVs as biomarkers in melanoma, as well as their role in the clinical setting in humans and animals. A summary of melanoma-specific protein and genomic EV markers is presented, followed by a discussion of the role EVs in monitoring disease progression and treatment response. Finally, herein, we reviewed the advantages and disadvantages of methods utilised to isolate EVs from bodily fluids in melanoma patients (human and animals) and describe some of the challenges that will need to be addressed before EVs can be introduced in the clinical setting.

Melanoma Biomarkers and Their Potential Application for In Vivo Diagnostic Imaging Modalities

Melanoma is the deadliest form of skin cancer and remains a diagnostic challenge in the dermatology clinic. Several non-invasive imaging techniques have been developed to identify melanoma. The signal source in each of these modalities is based on the alteration of physical characteristics of the tissue from healthy/benign to melanoma. However, as these characteristics are not always sufficiently specific, the current imaging techniques are not adequate for use in the clinical setting. A more robust way of melanoma diagnosis is to "stain" or selectively target the suspect tissue with a melanoma biomarker attached to a contrast enhancer of one imaging modality. Here, we categorize and review known melanoma diagnostic biomarkers with the goal of guiding skin imaging experts to design an appropriate diagnostic tool for differentiating between melanoma and benign lesions with a high specificity and sensitivity.

HER3-Receptor-Mediated STAT3 Activation Plays a Central Role in Adaptive Resistance toward Vemurafenib in Melanoma

Simple Summary

The major obstacle for the long-term success of targeted therapies in melanoma is the occurrence of resistance. Here, we present a new mechanism of targeted therapy resistance in melanoma where the treatment with the BRAF inhibitor vemurafenib causes an increased activation of HER3 via shed ligands. This is followed by an activation of STAT3 via HER3 and results in the expression of the STAT3 target gene SOX2. Pharmacological inhibition of HERs sensitizes melanoma cells toward vemurafenib treatment. Thus, blocking HER family members and especially HER3 in addition to targeted therapy treatment might prevent the occurrence of resistance.

Abstract

Melanoma is an aggressive form of skin cancer that is often characterized by activating mutations in the Mitogen-Activated Protein (MAP) kinase pathway, causing hyperproliferation of the cancer cells. Thus, inhibitors targeting this pathway were developed. These inhibitors are initially very effective, but the occurrence of resistance eventually leads to a failure of the therapy and is the major obstacle for clinical success. Therefore, investigating the mechanisms causing resistance and discovering ways to overcome them is essential for the success of therapy. Here, we observed that treatment of melanoma cells with the B-Raf Proto-Oncogene, Serine/Threonine Kinase (BRAF) inhibitor vemurafenib caused an increased cell surface expression and activation of human epidermal growth factor receptor 3 (HER3) by shed ligands. HER3 promoted the activation of signal transducer and activator of transcription 3 (STAT3) resulting in upregulation of the STAT3 target gene SRY-Box Transcription Factor 2 (SOX2) and survival of the cancer cells. Pharmacological blocking of HER led to a diminished STAT3 activation and increased sensitivity toward vemurafenib. Moreover, HER blocking sensitized vemurafenib-resistant cells to drug treatment. We conclude that the inhibition of the STAT3 upstream regulator HER might help to overcome melanoma therapy resistance toward targeted therapies.

Classification and Grading of Melanocytic Lesions in a Mouse Model of NRAS-driven Melanomagenesis

The mouse line carrying the Tg(Tyr-NRAS*Q61K)1Bee transgene is widely used to model in vivo NRAS-driven melanomagenesis. Although the pathological features of this model are well described, classification and interpretation of the resulting proliferative lesions-including their origin, evolution, grading, and pathobiological significance-are still unclear and not supported by molecular and biological evidence. Focusing on their classification and grading, this work combines histopathology and expression analysis (using both immunohistochemistry [IHC] and quantitative PCR) of selected biomarkers to study the full spectrum of cutaneous and lymph nodal melanocytic proliferations in the Tg(Tyr-NRAS*Q61K)1Bee mouse. The analysis of cutaneous and lymph nodal melanocytic proliferations has demonstrated that a linear correlation exists between tumor grade and Ki-67, microphthalmia-associated transcription factor (MITF), gp100, and nestin IHC, with a significantly increased expression in high-grade lesions compared with low-grade lesions. The accuracy of the assessment of MITF IHC in melanomas was also confirmed by quantitative PCR analysis. In conclusion, we believe the incorporation of MITF, Ki-67, gp100, and nestin analysis into the histopathological classification/grading scheme of melanocytic proliferations described for this model will help to assess with accuracy the nature and evolution of the phenotype, monitor disease progression, and predict response to experimental treatment or other preclinical manipulations.

Survivin modulation in the antimelanoma activity of prodiginines

Melanoma is a type of skin cancer with an elevated incidence of metastasis and chemoresistance. Such features hamper treatment success of these neoplasms, demanding the search for new therapeutic options. Using a two-step resin-based approach, we recently demonstrated that cytotoxic prodiginines bind to the inhibitor of apoptosis protein, survivin. Herein, we explore the role of survivin in melanoma and whether its modulation is related to the antimelanoma properties of three cytotoxic prodiginines (prodigiosin, cyclononylprodigiosin, and nonylprodigiosin) isolated from marine bacteria. In melanoma patients and cell lines, survivin is overexpressed, and higher levels negatively impact survival. All three prodiginines caused a decrease in cell growth with reduced cytotoxicity after 24 h compared to 72 h treatment, suggesting that low concentrations promote cytostatic effects in SK-Mel-19 (BRAF mutant) and SK-Mel-28 (BRAF mutant), but not in SK-Mel-147 (NRAS mutant). An increase in G1 population was observed after 24 h treatment with prodigiosin and cyclononylprodigiosin in SK-Mel-19. Further studies indicate that prodigiosin induced apoptosis and DNA damage, as detected by increased caspase-3 cleavage and histone H2AX phosphorylation, further arguing for the downregulation of survivin. Computer simulations suggest that prodigiosin and cyclononylprodigiosin bind to the BIR domain of survivin. Moreover, knockdown of survivin increased long-term toxicity of prodigiosin, as observed by reduced clonogenic capacity, but did not alter short-term cytotoxicity. In summary, prodiginine treatment provoked cytostatic rather than cytotoxic effects, cell cycle arrest at G0/G1 phase, induction of apoptosis and DNA damage, downregulation of survivin, and decreased clonogenic capacity in survivin knockdown cells.

α-MSH-PE38KDEL Kills Melanoma Cells via Modulating Erk1/2/MITF/TYR Signaling in an MC1R-Dependent Manner

Background/Objective

The immunotoxin α-MSH-PE38KDEL consisting of α-MSH and PE38KDEL showed high cytotoxicity on MSH receptor-positive melanoma cells, suggesting that α-MSH-PE38KDEL might be a potent drug for the treatment of melanoma. Herein, we explored whether the Erk1/2/MITF/TYR signaling, a verified target of α-MSH/MC1R, was involved in α-MSH-PE38KDEL-mediated cytotoxicity.

Methods

Human melanoma cell line A375, mouse melanoma cell line B16-F10, human breast cancer cell line MDA-MB-231 and human primary epidermal melanocytes (HEMa) with different expression levels of MC1R were used in this study. Cell apoptosis and viability were determined by using flow cytometry and MTT assays. Protein expressions were tested by Western blotting.

Results

The expression levels of MC1R in A375 and B16-F10 cells were significantly higher than that of MDA-MB-231 and HEMa. α-MSH-PE38KDEL treatment induced a significant inhibition in cell viability in A375 and B16-F10 cells, while showed no obvious influence in the viability of MDA-MB-231 and HEMa cells. However, knockdown of MC1R abolished α-MSH-PE38KDEL role in promoting cell apoptosis in A375 and B16-F10 cells, and upregulation of MC1R endowed α-MSH-PE38KDEL function to promote cell apoptosis in MDA-MB-231 and HEMa cells. Additionally, α-MSH-PE38KDEL treatment increased the phosphorylation levels of Erk1/2 and MITF (S73), and decreased MITF and TYR expressions in an MC1R-dependent manner. All of the treatments, including inhibition of Erk1/2 with PD98059, MC1R downregulation and MITF overexpression weakened the anti-tumor role of α-MSH-PE38KDEL in melanoma.

Conclusion

Collectively, this study indicates that α-MSH-PE38KDEL promotes melanoma cell apoptosis via modulating Erk1/2/MITF/TYR signaling in an MC1R-dependent manner.

Nuclear factor I/B mediates epithelial-mesenchymal transition in human melanoma cells through ZEB1

The relationship between nuclear factor I/B (NFIB) and cancer attracts growing research interest. NFIB has diverse and specific roles in tumor progression and invasion. However, the potential effects and functions of this transcription factor in melanoma remain unclear. The present study sought to determine the distinguishing properties of NFIB in melanoma cells. Immunohistochemical examination of the tissues of 15 patients with melanoma indicated that the expression of NFIB was high in melanoma specimens, compared with the benign nevus and normal skin specimens. In addition, the relationship between high NFIB expression and low overall survival rate was assessed. Functional studies demonstrated that NFIB enhanced the malignancy of melanoma, including proliferation, migration and invasion. In addition, NFIB silencing in A375 and A875 cell lines inhibited the process of epithelial-mesenchymal transition (EMT), upregulated E-cadherin and zona occludens-1, but suppressed N-cadherin and vimentin expression. These findings may suggest a new function of NFIB in promoting the migration and invasion of melanoma cells. Therefore, the present study further evaluated the association between NFIB and zinc finger protein E-box binding homeobox-1 (ZEB1) in melanoma. Mechanistic experiments revealed that NFIB exerted its roles during EMT by regulating ZEB1. Overall, the present data indicates that NFIB promotes the malignancy of melanoma, particularly EMT, by modulating the ZEB1 axis, such as ZEB2, ATM and CHK1, which may represent a potential molecular therapeutic target in melanoma.

A Framework of Major Tumor-Promoting Signal Transduction Pathways Implicated in Melanoma-Fibroblast Dialogue

Simple Summary

Melanoma cells reside in a complex stromal microenvironment, which is a critical component of disease onset and progression. Mesenchymal or fibroblastic cell type are the most abundant cellular element of tumor stroma. Factors secreted by melanoma cells can activate non-malignant associated fibroblasts to become melanoma associate fibroblasts (MAFs). MAFs promote tumorigenic features by remodeling the extracellular matrix, supporting tumor cells proliferation, neo-angiogenesis and drug resistance. Additionally, environmental factors may contribute to the acquisition of pro-tumorigenic phenotype of fibroblasts. Overall, in melanoma, perturbed tissue homeostasis contributes to modulation of major oncogenic intracellular signaling pathways not only in tumor cells but also in neighboring cells. Thus, targeted molecular therapies need to be considered from the reciprocal point of view of melanoma and stromal cells.

Abstract

The development of a modified stromal microenvironment in response to neoplastic onset is a common feature of many tumors including cutaneous melanoma. At all stages, melanoma cells are embedded in a complex tissue composed by extracellular matrix components and several different cell populations. Thus, melanomagenesis is not only driven by malignant melanocytes, but also by the altered communication between melanocytes and non-malignant cell populations, including fibroblasts, endothelial and immune cells. In particular, cancer-associated fibroblasts (CAFs), also referred as melanoma-associated fibroblasts (MAFs) in the case of melanoma, are the most abundant stromal cells and play a significant contextual role in melanoma initiation, progression and metastasis. As a result of dynamic intercellular molecular dialogue between tumor and the stroma, non-neoplastic cells gain specific phenotypes and functions that are pro-tumorigenic. Targeting MAFs is thus considered a promising avenue to improve melanoma therapy. Growing evidence demonstrates that aberrant regulation of oncogenic signaling is not restricted to transformed cells but also occurs in MAFs. However, in some cases, signaling pathways present opposite regulation in melanoma and surrounding area, suggesting that therapeutic strategies need to carefully consider the tumor–stroma equilibrium. In this novel review, we analyze four major signaling pathways implicated in melanomagenesis, TGF-β, MAPK, Wnt/β-catenin and Hyppo signaling, from the complementary point of view of tumor cells and the microenvironment.

Identification of Prognostic Biomarkers of Cutaneous Melanoma Based on Analysis of Tumor Mutation Burden

Background

Immunotherapy offers a novel approach for the treatment of cutaneous melanoma, but the clinical efficiency varies for individual patients. In consideration of the high cost and adverse effects of immunotherapy, it is essential to explore the predictive biomarkers of outcomes. Recently, the tumor mutation burden (TMB) has been proposed as a predictive prognosticator of the immune response.

Method

RNA-seq and somatic mutation datasets of 472 cutaneous melanoma patients were downloaded from The Cancer Genome Atlas (TCGA) database to analyze mutation type and TMB. Differently expressed genes (DEGs) were identified for functional analysis. TMB-related signatures were identified via LASSO and multivariate Cox regression analysis. The association between mutants of signatures and immune cells was evaluated from the TIMER database. Furthermore, the Wilcox test was applied to assess the difference in immune infiltration calculated by the CIBERSORT algorithm in risk groupings.

Results

C>T substitutions and TTN were the most common SNV and mutated gene, respectively. Patients with low TMB presented poor prognosis. DEGs were mainly implicated in skin development, cell cycle, DNA replication, and immune-associated crosstalk pathways. Furthermore, a prognostic model consisting of eight TMB-related genes was developed, which was found to be an independent risk factor for treatment outcome. The mutational status of eight TMB-related genes was associated with a low level of immune infiltration. In addition, the immune infiltrates of CD4+ and CD8+ T cells, NK cells, and M1 macrophages were higher in the low-risk group, while those of M0 and M2 macrophages were higher in the high-risk group.

Conclusion

Our study demonstrated that a higher TMB was associated with favorable survival outcome in cutaneous melanoma. Moreover, a close association between prognostic model and immune infiltration was identified, providing a new potential target for immunotherapy.

The Non-Coding Landscape of Cutaneous Malignant Melanoma: A Possible Route to Efficient Targeted Therapy

Considered to be highly lethal if not diagnosed in early stages, cutaneous malignant melanoma is among the most aggressive and treatment-resistant human cancers, and its incidence continues to rise, largely due to ultraviolet radiation exposure, which is the main carcinogenic factor. Over the years, researchers have started to unveil the molecular mechanisms by which malignant melanoma can be triggered and sustained, in order to establish specific, reliable biomarkers that could aid the prognosis and diagnosis of this fatal disease, and serve as targets for development of novel efficient therapies. The high mutational burden and heterogeneous nature of melanoma shifted the main focus from the genetic landscape to epigenetic and epitranscriptomic modifications, aiming at elucidating the role of non-coding RNA molecules in the fine tuning of melanoma progression. Here we review the contribution of microRNAs and lncRNAs to melanoma invasion, metastasis and acquired drug resistance, highlighting their potential for clinical applications as biomarkers and therapeutic targets.

The Influence of Tumor Microenvironment on Immune Escape of Melanoma

The low efficiency of currently-used anti-cancer therapies poses a serious challenge, especially in the case of malignant melanoma, a cancer characterized by elevated invasiveness and relatively high mortality rate. The role of the tumor microenvironment in the progression of melanoma and its acquisition of resistance to treatment seems to be the main focus of recent studies. One of the factors that, in normal conditions, aids the organism in its fight against the cancer and, following the malignant transformation, adapts to facilitate the development of the tumor is the immune system. A variety of cell types, i.e., T and B lymphocytes, macrophages, and dendritic and natural killer cells, as well as neutrophils, support the growth and invasiveness of melanoma cells, utilizing a plethora of mechanisms, including secretion of pro-inflammatory molecules, induction of inhibitory receptors expression, or depletion of essential nutrients. This review provides a comprehensive summary of the processes regulated by tumor-associated cells that promote the immune escape of melanoma cells. The described mechanisms offer potential new targets for anti-cancer treatment and should be further studied to improve currently-employed therapies.