Genetic progression of malignant melanoma

Association of miR-146a-5p and miR-21-5p with Prognostic Features in Melanomas

BACKGROUND

Cutaneous melanoma (CM) is one of the most lethal tumors among skin cancers and its incidence is rising worldwide. Recent data support the role of microRNAs (miRNAs) in melanoma carcinogenesis and their potential use as disease biomarkers.

METHODS

We quantified the expression of miR-146a-5p and miR-21-5p in 170 formalin-fixed paraffin embedded (FFPE) samples of CM, namely 116 superficial spreading melanoma (SSM), 26 nodular melanoma (NM), and 28 lentigo maligna melanoma (LMM). We correlated miRNA expression with specific histopathologic features including Breslow thickness (BT), histological subtype, ulceration and regression status, and mitotic index.

RESULTS

miR-146a-5p and miR-21-5p were significantly higher in NM compared to SSM and LMM. The positive correlation between miR-146a-5p and miR-21-5p expression and BT was confirmed for both miRNAs in SSM. Considering the ulceration status, we assessed that individual miR-21-5p expression was significantly higher in ulcerated CMs. The increased combined expression of the two miRNAs was strongly associated with ulceration (p = 0.0093) and higher mitotic rate (≥1/mm2) (p = 0.0005). We demonstrated that the combination of two-miRNA expression and prognostic features (BT and ulceration) can better differentiate cutaneous melanoma prognostic groups, considering overall survival and time-to-relapse clinical outcomes. Specifically, miRNA expression can further stratify prognostic groups among patients with BT ≥ 0.8 mm but without ulceration. Our findings provide further insights into the characterization of CM with specific prognostic features. The graphical abstract was created with BioRender.com.

Diagnosing Cutaneous Melanocytic Tumors in the Molecular Era: Updates and Review of Literature

Over the past decade, molecular and genomic discoveries have experienced unprecedented growth, fundamentally reshaping our comprehension of melanocytic tumors. This review comprises three main sections. The first part gives an overview of the current genomic landscape of cutaneous melanocytic tumors. The second part provides an update on the associated molecular tests and immunohistochemical stains that are helpful for diagnostic purposes. The third section briefly outlines the diverse molecular pathways now utilized for the classification of cutaneous melanomas. The primary goal of this review is to provide a succinct overview of the molecular pathways involved in melanocytic tumors and demonstrate their practical integration into the realm of diagnostic aids. As the molecular and genomic knowledge base continues to expand, this review hopes to serve as a valuable resource for healthcare professionals, offering insight into the evolving molecular landscape of cutaneous melanocytic tumors and its implications for patient care.

Genetic Concordance in Primary Cutaneous Melanoma and Matched Metastasis: A Systematic Review and Meta-Analysis

Studying primary melanoma and its corresponding metastasis has twofold benefits. Firstly, to better understand tumor biology, and secondly, to determine which sample should be examined in assessing drug targets. This study systematically analyzed all the literature on primary melanoma and its matched metastasis. Following PRISMA guidelines, we searched multiple medical databases for relevant publications from January 2000 to December 2022, assessed the quality of the primary-level studies using the QUIPS tool, and summarized the concordance rate of the most reported genes using the random-effects model. Finally, we evaluated the inter-study heterogeneity using the subgroup analysis. Thirty-one studies investigated the concordance of BRAF and NRAS in 1220 and 629 patients, respectively. The pooled concordance rate was 89.4% [95% CI: 84.5; 93.5] for BRAF and 97.8% [95% CI: 95.8; 99.4] for NRAS. When high-quality studies were considered, only BRAF mutation status consistency increased. Five studies reported the concordance status of c-KIT (93%, 44 patients) and TERT promoter (64%, 53 patients). Lastly, three studies analyzed the concordance of cancer genes involved in the signaling pathways, apoptosis, and proliferation, such as CDKN2A (25%, four patients), TP53 (44%, nine patients), and PIK3CA (20%, five patients). Our study found that the concordance of known drug targets (mainly BRAF) during melanoma progression is higher than in previous meta-analyses, likely due to advances in molecular techniques. Furthermore, significant heterogeneity exists in the genes involved in the melanoma genetic makeup; although our results are based on small patient samples, more research is necessary for validation.

In Vitro Antiproliferative Effect of Cannabis Extract PHEC-66 on Melanoma Cell Lines

Melanoma, an aggressive form of skin cancer, can be fatal if not diagnosed and treated early. Melanoma is widely recognized to resist advanced cancer treatments, including immune checkpoint inhibitors, kinase inhibitors, and chemotherapy. Numerous studies have shown that various Cannabis sativa extracts exhibit potential anticancer effects against different types of tumours both in vitro and in vivo. This study is the first to report that PHEC-66, a Cannabis sativa extract, displays antiproliferative effects against MM418-C1, MM329 and MM96L melanoma cells. Although these findings suggest that PHEC-66 has promising potential as a pharmacotherapeutic agent for melanoma treatment, further research is necessary to evaluate its safety, efficacy, and clinical applications.

Melanoma Cells Produce Large Vesicular-Bodies That Cause Rapid Disruption of Brain Endothelial Barrier-Integrity and Disassembly of Junctional Proteins

It is known that many cells produce extracellular vesicles, and this includes a range of different cancer cell types. Here we demonstrate the profound effects of large vesicular-like bodies produced by melanoma cells on the barrier integrity of human brain endothelial cells. These vesicular-bodies have not been fully characterised but range in size from ~500 nm to >10 µm, are surrounded by membrane and are enzymatically active based on cell-tracker incorporation. Their size is consistent with previously reported large oncosomes and apoptotic bodies. We demonstrate that these melanoma-derived vesicular-bodies rapidly affect brain endothelial barrier integrity, measured using ECIS biosensor technology, where the disruption is evident within ~60 min. This disruption involves acquisition of the vesicles through transcellular uptake into the endothelial cells. We also observed extensive actin-rearrangement, actin removal from the paracellular boundary of the endothelial cells and envelopment of the vesicular-bodies by actin. This was concordant with widespread changes in CD144 localisation, which was consistent with the loss of junctional strength. High-resolution confocal imaging revealed proximity of the melanoma vesicular-bodies juxtaposed to the endothelial nucleus, often containing fragmented DNA themselves, raising speculation over this association and potential delivery of nuclear material into the brain endothelial cells. The disruption of the endothelial cells occurs in a manner that is faster and completely distinct to that of invasion by intact melanoma cells. Given the clinical observation of large vesicles in the circulation of melanoma patients by others, we hypothesize their involvement in weakening or priming the brain vasculature for melanoma invasion.

Metastatic Melanoma: Liquid Biopsy as a New Precision Medicine Approach

Precision medicine has driven a major change in the treatment of many forms of cancer. The discovery that each patient is different and each tumor mass has its own characteristics has shifted the focus of basic and clinical research to the singular individual. Liquid biopsy (LB), in this sense, presents new scenarios in personalized medicine through the study of molecules, factors, and tumor biomarkers in blood such as circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), exosomes and circulating tumor microRNAs (ct-miRNAs). Moreover, its easy application and complete absence of contraindications for the patient make this method applicable in a great many fields. Melanoma, given its highly heterogeneous characteristics, is a cancer form that could significantly benefit from the information linked to liquid biopsy, especially in the treatment management. In this review, we will focus our attention on the latest applications of liquid biopsy in metastatic melanoma and possible developments in the clinical setting.

hOA-DN30: a highly effective humanized single-arm MET antibody inducing remission of ‘MET-addicted’ cancers

Background

The tyrosine kinase receptor encoded by the MET oncogene is a major player in cancer. When MET is responsible for the onset and progression of the transformed phenotype (MET-addicted cancers), an efficient block of its oncogenic activation results in potent tumor growth inhibition.

Methods

Here we describe a molecular engineered MET antibody (hOA-DN30) and validate its pharmacological activity in MET-addicted cancer models in vitro and in vivo. Pharmacokinetics and safety profile in non-human primates have also been assessed.

Results

hOA-DN30 efficiently impaired MET activation and the intracellular signalling cascade by dose and time dependent removal of the receptor from the cell surface (shedding). In vitro, the antibody suppressed cell growth by blocking cell proliferation and by concomitantly inducing cell death in multiple MET-addicted human tumor cell lines. In mice xenografts, hOA-DN30 induced an impressive reduction of tumor masses, with a wide therapeutic window. Moreover, the antibody showed high therapeutic efficacy against patient-derived xenografts generated from MET-addicted gastric tumors, leading to complete tumor regression and long-lasting effects after treatment discontinuation. Finally, hOA-DN30 showed a highly favorable pharmacokinetic profile and substantial tolerability in Cynomolgus monkeys.

Conclusions

hOA-DN30 unique ability to simultaneously erase cell surface MET and release the ‘decoy’ receptor extracellular region results in a paramount MET blocking action. Its remarkable efficacy in a large number of pre-clinical models, as well as its pharmacological features and safety profile in non-human primates, strongly envisage a successful clinical application of this novel single-arm MET therapeutic antibody for the therapy of MET-addicted cancers.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-022-02320-6.

UV-Induced Somatic Mutations Driving Clonal Evolution in Healthy Skin, Nevus, and Cutaneous Melanoma

Introduction: Due to its aggressiveness, cutaneous melanoma (CM) is responsible for most skin cancer-related deaths worldwide. The origin of CM is closely linked to the appearance of UV-induced somatic mutations in melanocytes present in normal skin or in CM precursor lesions (nevi or dysplastic nevi). In recent years, new NGS studies performed on CM tissue have increased the understanding of the genetic somatic changes underlying melanomagenesis and CM tumor progression. Methods: We reviewed the literature using all important scientific databases. All articles related to genomic mutations in CM as well as normal skin and nevi were included, in particular those related to somatic mutations produced by UV radiation. Conclusions: CM development and progression are strongly associated with exposure to UV radiation, although each melanoma subtype has different characteristic genetic alterations and evolutionary trajectories. While BRAF and NRAS mutations are common in the early stages of tumor development for most CM subtypes, changes in CDKN2A, TP53 and PTEN, together with TERT promoter mutations, are especially common in advanced stages. Additionally, large genome duplications, loss of heterozygosity, and copy number variations are hallmarks of metastatic disease. Finally, the mutations driving melanoma targeted-therapy drug resistance are also summarized. The complete sequential stages of clonal evolution leading to CM onset from normal skin or nevi are still unknown, so further studies are needed in this field to shed light on the molecular pathways involved in CM malignant transformation and in melanoma acquired drug resistance.

Molecular Pathology of Skin Melanoma: Epidemiology, Differential Diagnostics, Prognosis and Therapy Prediction

Similar to other malignancies, TCGA network efforts identified the detailed genomic picture of skin melanoma, laying down the basis of molecular classification. On the other hand, genome-wide association studies discovered the genetic background of the hereditary melanomas and the susceptibility genes. These genetic studies helped to fine-tune the differential diagnostics of malignant melanocytic lesions, using either FISH tests or the myPath gene expression signature. Although the original genomic studies on skin melanoma were mostly based on primary tumors, data started to accumulate on the genetic diversity of the progressing disease. The prognostication of skin melanoma is still based on staging but can be completed with gene expression analysis (DecisionDx). Meanwhile, this genetic knowledge base of skin melanoma did not turn to the expected wide array of target therapies, except the BRAF inhibitors. The major breakthrough of melanoma therapy was the introduction of immune checkpoint inhibitors, which showed outstanding efficacy in skin melanoma, probably due to their high immunogenicity. Unfortunately, beyond BRAF, KIT mutations and tumor mutation burden, no clinically validated predictive markers exist in melanoma, although several promising biomarkers have been described, such as the expression of immune-related genes or mutations in the IFN-signaling pathway. After the initial success of either target or immunotherapies, sooner or later, relapses occur in the majority of patients, due to various induced genetic alterations, the diagnosis of which could be developed to novel predictive genetic markers.

Genomic and Transcriptomic Underpinnings of Melanoma Genesis, Progression, and Metastasis

Melanoma is a deadly skin cancer with rapidly increasing incidence worldwide. The discovery of the genetic drivers of melanomagenesis in the last decade has led the World Health Organization to reclassify melanoma subtypes by their molecular pathways rather than traditional clinical and histopathologic features. Despite this significant advance, the genomic and transcriptomic drivers of metastatic progression are less well characterized. This review describes the known molecular pathways of cutaneous and uveal melanoma progression, highlights recently identified pathways and mediators of metastasis, and touches on the influence of the tumor microenvironment on metastatic progression and treatment resistance. While targeted therapies and immune checkpoint blockade have significantly aided in the treatment of advanced disease, acquired drug resistance remains an unfortunately common problem, and there is still a great need to identify potential prognostic markers and novel therapeutic targets to aid in such cases.

Deep Proteomic Analysis on Biobanked Paraffine-Archived Melanoma with Prognostic/Predictive Biomarker Read-Out

The discovery of novel protein biomarkers in melanoma is crucial. Our introduction of formalin-fixed paraffin-embedded (FFPE) tumor protocol provides new opportunities to understand the progression of melanoma and open the possibility to screen thousands of FFPE samples deposited in tumor biobanks and available at hospital pathology departments. In our retrospective biobank pilot study, 90 FFPE samples from 77 patients were processed. Protein quantitation was performed by high-resolution mass spectrometry and validated by histopathologic analysis. The global protein expression formed six sample clusters. Proteins such as TRAF6 and ARMC10 were upregulated in clusters with enrichment for shorter survival, and proteins such as AIFI1 were upregulated in clusters with enrichment for longer survival. The cohort's heterogeneity was addressed by comparing primary and metastasis samples, as well comparing clinical stages. Within immunotherapy and targeted therapy subgroups, the upregulation of the VEGFA-VEGFR2 pathway, RNA splicing, increased activity of immune cells, extracellular matrix, and metabolic pathways were positively associated with patient outcome. To summarize, we were able to (i) link global protein expression profiles to survival, and they proved to be an independent prognostic indicator, as well as (ii) identify proteins that are potential predictors of a patient's response to immunotherapy and targeted therapy, suggesting new opportunities for precision medicine developments.

Organ Specific Copy Number Variations in Visceral Metastases of Human Melanoma

Malignant melanoma is one of the most aggressive skin cancers with high potential of visceral dissemination. Since the information about melanoma genomics is mainly based on primary tumors and lymphatic or skin metastases, an autopsy-based visceral metastasis biobank was established. We used copy number variation arrays (N = 38 samples) to reveal organ specific alterations. Results were partly completed by proteomic analysis. A significant increase of high-copy number gains was found in an organ-specific manner, whereas copy number losses were predominant in brain metastases, including the loss of numerous DNA damage response genes. Amplification of many immune genes was also observed, several of them are novel in melanoma, suggesting that their ectopic expression is possibly underestimated. This "immunogenic mimicry" was exclusive for lung metastasis. We also provided evidence for the possible autocrine activation of c-MET, especially in brain and lung metastases. Furthermore, frequent loss of 9p21 locus in brain metastases may predict higher metastatic potential to this organ. Finally, a significant correlation was observed between BRAF gene copy number and mutant allele frequency, mainly in lung metastases. All of these events may influence therapy efficacy in an organ specific manner, which knowledge may help in alleviating difficulties caused by resistance.

BRAF Mutation Analysis in Primary Acral Melanoma of 41 Cases from South of Iran

Background & Objective

Acral melanoma (AM) is a common type of cutaneous melanoma that occurs in the skin of the palms, soles, and nail beds. This malignancy, like other types of cancer, has different genetic alterations. To date, despite decades of research the roles of oncogenic BRAF mutations in the pathogenesis of AM has not been fully clarified. The present study was designed to identify V600E mutation in patients with AM from the south of Iran.

Methods

The samples were collected from the pathology lab archive of Shiraz University of Medical Sciences (2015-2020). A total of 41 patients with primary invasive AM underwent excisional biopsy or amputation were collected to evaluate BRAF V600E mutation using Polymerase Chain Reaction (PCR) and Sanger sequencing.

Results

Total number of 41cases (21 male and 20 female) and age range of 34-87 years were enrolled. The histological subtypes were 24 acral lentiginous melanomas (ALM), 10 cases of nodular melanoma (NM), and 7 cases of superficial spreading melanoma (SSM). In our study, only one case (a 44-year-old male with nail bed AM and the histological subtype of acral lentigenous melanoma) showed BRAF-V600E mutation.

Conclusion

These findings suggest that the population of our interest showed a very low prevalence of this mutation providing novel insights into the pathobiology of AM and its related treatment.

PERK mediates resistance to BRAF inhibition in melanoma with impaired PTEN

Targeting mutant BRAF in patients with melanomas harboring this oncogene has been highly successful as a first-line treatment, but other mutations may affect its efficacy and alter the route of acquired resistance resulting in recurrence and poor prognosis. As an evolving strategy, melanoma treatment needs to be expanded to include targets based on newly discovered emerging molecules and pathways. We here show that PERK plays a critical role in BRAF inhibitor-acquired resistance in melanoma with impaired PTEN. Inhibition of PERK by either shRNA or a pharmacological inhibitor blocked the growth of BRAF inhibitor-resistant melanoma with impaired PTEN in vitro and in vivo, suggesting an effective approach against melanomas with mutant BRAF and PTEN deficiency. Our current findings, along with our previous discovery that the AXL/AKT axis mediates resistance to BRAF inhibition in melanoma with wild-type PTEN, provide new insights toward a strategy for combating BRAF inhibition-acquired resistance in BRAF mutant melanoma with different PTEN statuses.

Learning from Embryogenesis-A Comparative Expression Analysis in Melanoblast Differentiation and Tumorigenesis Reveals miRNAs Driving Melanoma Development

Malignant melanoma is one of the most dangerous tumor types due to its high metastasis rates and a steadily increasing incidence. During tumorigenesis, the molecular processes of embryonic development, exemplified by epithelial-mesenchymal transition (EMT), are often reactivated. For melanoma development, the exact molecular differences between melanoblasts, melanocytes, and melanoma cells are not completely understood. In this study, we aimed to identify microRNAs (miRNAs) that promote melanoma tumorigenesis and progression, based on an in vitro model of normal human epidermal melanocyte (NHEM) de-differentiation into melanoblast-like cells (MBrCs). Using miRNA-sequencing and differential expression analysis, we demonstrated in this study that a majority of miRNAs have an almost equal expression level in NHEMs and MBrCs but are significantly differentially regulated in primary tumor- and metastasis-derived melanoma cell lines. Further, a target gene analysis of strongly regulated but functionally unknown miRNAs yielded the implication of those miRNAs in many important cellular pathways driving malignancy. We hypothesize that many of the miRNAs discovered in our study are key drivers of melanoma development as they account for the tumorigenic potential that differentiates melanoma cells from proliferating or migrating embryonic cells.

Xmrks the Spot: Fish Models for Investigating Epidermal Growth Factor Receptor Signaling in Cancer Research

Studies conducted in several fish species, e.g., Xiphophorus hellerii (green swordtail) and Xiphophorus maculatus (southern platyfish) crosses, Oryzias latipes (medaka), and Danio rerio (zebrafish), have identified an oncogenic role for the receptor tyrosine kinase, Xmrk, a gene product closely related to the human epidermal growth factor receptor (EGFR), which is associated with a wide variety of pathological conditions, including cancer. Comparative analyses of Xmrk and EGFR signal transduction in melanoma have shown that both utilize STAT5 signaling to regulate apoptosis and cell proliferation, PI3K to modulate apoptosis, FAK to control migration, and the Ras/Raf/MEK/MAPK pathway to regulate cell survival, proliferation, and differentiation. Further, Xmrk and EGFR may also modulate similar chemokine, extracellular matrix, oxidative stress, and microRNA signaling pathways in melanoma. In hepatocellular carcinoma (HCC), Xmrk and EGFR signaling utilize STAT5 to regulate cell proliferation, and Xmrk may signal through PI3K and FasR to modulate apoptosis. At the same time, both activate the Ras/Raf/MEK/MAPK pathway to regulate cell proliferation and E-cadherin signaling. Xmrk models of melanoma have shown that inhibitors of PI3K and MEK have an anti-cancer effect, and in HCC, that the steroidal drug, adrenosterone, can prevent metastasis and recover E-cadherin expression, suggesting that fish Xmrk models can exploit similarities with EGFR signal transduction to identify and study new chemotherapeutic drugs.

Adipokines in the Skin and in Dermatological Diseases

Adipokines are the primary mediators of adipose tissue-induced and regulated systemic inflammatory diseases; however, recent findings revealed that serum levels of various adipokines correlate also with the onset and the severity of dermatological diseases. Importantly, further data confirmed that the skin serves not only as a target for adipokine signaling, but may serve as a source too. In this review, we aim to provide a complex overview on how adipokines may integrate into the (patho) physiological conditions of the skin by introducing the cell types, such as keratinocytes, fibroblasts, and sebocytes, which are known to produce adipokines as well as the signals that target them. Moreover, we discuss data from in vivo and in vitro murine and human studies as well as genetic data on how adipokines may contribute to various aspects of the homeostasis of the skin, e.g., melanogenesis, hair growth, or wound healing, just as to the pathogenesis of dermatological diseases such as psoriasis, atopic dermatitis, acne, rosacea, and melanoma.

Spectrum of Mesenchymal-Epithelial Transition Aberrations and Potential Clinical Implications: Insights From Integrative Pancancer Analysis

Background

The receptor tyrosine kinase mesenchymal-epithelial transition factor (MET) is frequently altered in cancers and is a common therapeutic target for cancers with MET variants. However, abnormal MET alterations and their associations with patient outcome across different cancer types have not been studied simultaneously. In this study, we try to fill the vacancy in a comprehensive manner and capture the full MET alteration spectrum.

Methods

A total of 10,967 tumor samples comprising 32 cancer types from The Cancer Genome Atlas (TCGA) datasets were analyzed for MET abnormal expression, mutations, and copy number variants (CNVs).

Results

MET abnormal expression, alteration frequency, mutation site distribution, and functional impact varied across different cancer types. Lung adenocarcinoma (LUAD) has most targetable mutations located in the juxtamembrane domain, and both high expression and amplification of MET are significantly associated with poor prognosis. Kidney renal papillary cell carcinoma (KIRP) harbored the third highest alteration frequency of MET, which was dominated by mutations. While most mutations were in the Pkinase_Tyr domain, a few were targetable. Pancreatic adenocarcinoma (PAAD) harbors very few alterations, but increased MET expression is associated with poor outcomes. Esophageal carcinoma (ESCA), stomach adenocarcinoma (STAD), and ovarian serous cystadenocarcinoma (OV) had similar characteristics: a high frequency of MET CNVs but relatively few MET mutations, and high MET expression associated with poor prognosis.

Conclusion

This study provided significant and comprehensive information regarding MET abnormal expression, alterations (mutations and CNVs), and their clinical associations among 32 cancer types and offered insights into the full MET alteration spectrum and its implications for prognosis and treatment.

Essential Oils and Their Main Chemical Components: The Past 20 Years of Preclinical Studies in Melanoma

Simple Summary

In the last years, targeted therapy and immunotherapy modified the landscape for metastatic melanoma treatment. These therapeutic approaches led to an impressive improvement in patients overall survival. Unfortunately, the emergence of drug resistance and side effects occurring during therapy strongly limit the long-term efficacy of such treatments. Several preclinical studies demonstrate the efficacy of essential oils as antitumoral agents, and clinical trials support their use to reduce side effects emerging during therapy. In this review we have summarized studies describing the molecular mechanism through which essential oils induce in vitro and in vivo cell death in melanoma models. We also pointed to clinical trials investigating the use of essential oils in reducing the side effects experienced by cancer patients or those undergoing anticancer therapy. From this review emerged that further studies are necessary to validate the effectiveness of essential oils for the management of melanoma.

Abstract

The last two decades have seen the development of effective therapies, which have saved the lives of a large number of melanoma patients. However, therapeutic options are still limited for patients without BRAF mutations or in relapse from current treatments, and severe side effects often occur during therapy. Thus, additional insights to improve treatment efficacy with the aim to decrease the likelihood of chemoresistance, as well as reducing side effects of current therapies, are required. Natural products offer great opportunities for the discovery of antineoplastic drugs, and still represent a useful source of novel molecules. Among them, essential oils, representing the volatile fraction of aromatic plants, are always being actively investigated by several research groups and show promising biological activities for their use as complementary or alternative medicine for several diseases, including cancer. In this review, we focused on studies reporting the mechanism through which essential oils exert antitumor action in preclinical wild type or mutant BRAF melanoma models. We also discussed the latest use of essential oils in improving cancer patients’ quality of life. As evidenced by the many studies listed in this review, through their effect on apoptosis and tumor progression-associated properties, essential oils can therefore be considered as potential natural pharmaceutical resources for cancer management.

A Rare Complex BRAF Mutation Involving Codon V600 and K601 in Primary Cutaneous Melanoma: Case Report

BRAF is one of the most common mutated kinases detected in human cancer, particularly in cases of primary cutaneous melanomas (PCM). Mutations of the BRAF proto-oncogene, at the p.V600 codon, has been detected in more than 50% of primary and metastatic melanoma cells in clinical samples. In addition to the most frequent BRAF p.V600E mutation, corresponding to the single base pair substitution c.1799T>A, rarer mutations, within and outside the V600 codon, have been described. Expectedly, BRAF and MEK inhibitors (or their combination) have been poorly explored as potential therapeutic strategies in metastatic melanomas harboring this rare mutation. By using a set of sequencing techniques and immunohistochemistry, this work reports the genomic and clinical features of two melanoma patients showing a rare complex mutation affecting codon V600 and K601 of the BRAF gene, leading to a V600E2; K601I change. Specifically, these two patients show a distinct clinical behavior and significantly differ in their responses to BRAF and MEK inhibitors. Indeed, although this treatment has proven to be effective and safe in both cases, the observed variability between the two patients resulted as a direct consequence of the baseline extent of brain involvement, intracranial treatment failure as well as on the PTEN status.

Gene Expression Signature of BRAF Inhibitor Resistant Melanoma Spheroids

In vitro cell cultures are frequently used to define the molecular background of drug resistance. The majority of currently available data have been obtained from 2D in vitro cultures, however, 3D cell culture systems (spheroids) are more likely to behave similarly to in vivo conditions. Our major aim was to compare the gene expression signature of 2D and 3D cultured BRAFV600E mutant melanoma cell lines. We successfully developed BRAF-drug resistant cell lines from paired primary/metastatic melanoma cell lines in both 2D and 3D in vitro cultures. Using Affymetrix Human Gene 1.0 ST arrays, we determined the gene expression pattern of all cell lines. Our analysis revealed 1049 genes (562 upregulated and 487 downregulated) that were differentially expressed between drug-sensitive cells grown under different cell cultures. Pathway analysis showed that the differently expressed genes were mainly associated with the cell cycle, p53, and other cancer-related pathways. The number of upregulated genes (72 genes) was remarkably fewer when comparing the resistant adherent cells to cells that grow in 3D, and were associated with cell adhesion molecules and IGF1R signalling. Only 1% of the upregulated and 5.6% of the downregulated genes were commonly altered between the sensitive and the resistant spheroids. Interestingly, we found several genes (BNIP3, RING1 and ABHD4) with inverse expression signature between sensitive and resistant spheroids, which are involved in anoikis resistance and cell cycle regulation. In summary, our study highlights gene expression alterations that might help to understand the development of acquired resistance in melanoma cells in tumour tissue.

Novel functional proteins coded by the human genome discovered in metastases of melanoma patients

In the advanced stages, malignant melanoma (MM) has a very poor prognosis. Due to tremendous efforts in cancer research over the last 10 years, and the introduction of novel therapies such as targeted therapies and immunomodulators, the rather dark horizon of the median survival has dramatically changed from under 1 year to several years. With the advent of proteomics, deep-mining studies can reach low-abundant expression levels. The complexity of the proteome, however, still surpasses the dynamic range capabilities of current analytical techniques. Consequently, many predicted protein products with potential biological functions have not yet been verified in experimental proteomic data. This category of 'missing proteins' (MP) is comprised of all proteins that have been predicted but are currently unverified. As part of the initiative launched in 2016 in the USA, the European Cancer Moonshot Center has performed numerous deep proteomics analyses on samples from MM patients. In this study, nine MPs were clearly identified by mass spectrometry in MM metastases. Some MPs significantly correlated with proteins that possess identical PFAM structural domains; and other MPs were significantly associated with cancer-related proteins. This is the first study to our knowledge, where unknown and novel proteins have been annotated in metastatic melanoma tumour tissue.

Frequent KIT mutations in skin lesions of patients with BRAF wild-type Langerhans cell histiocytosis

Langerhans cell histiocytosis (LCH) is characterized by mutations of the RAS-RAF-MAPK signaling pathway. We analyzed MAP2K1, NRAS and KIT mutation incidence in skin lesions of BRAF wild-type (wt) LCH patients. We evaluated the occurrence of MAP2K1, NRAS and KIT mutations in seven LCH and one indeterminate cell histiocytosis (ICH) patients. MAP2K1 mutation frequency was found to be 3/7 (42.9%) in LCH and also found in ICH. Similarly, the KIT mutation frequency was found to be equally prevalent (4/7, 57.1%) in LCH and also occurred in ICH. Involvement of KIT exons in LCH-ICH indicated that exon 9/11/18 were equally prevalent followed by exon 13. This exploratory analysis on BRAF-wt LCH revealed a KIT mutation rate comparable to MAP2K1. Although the detected KIT mutations are different from activating mutations found in other KIT-dependent neoplasms, our data suggest that KIT-inhibitors might have a role in treating BRAF-wt LCH patients.

Resistance of melanoma cells to anticancer treatment: a role of vascular endothelial growth factor

Melanoma is one of the most aggressive and resistant to treatment neoplasms. There are still many challenges despite many promising advances in anticancer treatment. Currently, the main problem for all types of treatment is associated with heterogeneity. Due to heterogeneity of cancer cells, "precise" targeting of a medicine against a single phenotype limits the efficacy of treatment and affects resistance to applied therapy. Therefore it is important to understand aetiology and reasons for heterogeneity in order to develop effective and long-lasting treatment. This review summarises roles of vascular endothelial growth factor (VEGF) that may stimulate growth of a melanoma tumour irrespective of its proangiogenic effects, contributing to cancer heterogeneity. VEGF triggers processes associated with extracellular matrix remodelling, cell migration, invasion, angiogenesis, inhibition of immune responses and favours phenotypic plasticity and epithelial-mesenchymal transition. Consequently, it participates in mechanisms of interactions between melanoma cancer cells and microenvironment and it can modify sensitivity to therapeutic factors.

KIT Mutation Incidence and Pattern of Melanoma in Central Europe

Data on the KIT mutation rate in melanoma in the central European region is missing. Accordingly, in a cohort of 79 BRAF/NRAS double wild type cutaneous melanoma and 17 mucosal melanoma KIT mutation was assessed by Sanger sequencing of exons 9,11,13,17 and 18. In this cutaneous melanoma cohort KIT mutation frequency was found to be 34/79 (43.04%) with a significantly higher rate in acrolentiginous melanoma (ALM) as compared to UV-induced common variants (20/34, 58.8% versus 14/45, 31.1%, p = 0.014). In the double wild type mucosal melanoma cohort the KIT mutation frequency was found to be comparable (41.2%). The actual frequency of KIT mutation in the original 227 patient cutaneous melanoma cohort was 34/227, 14.9%. Exon 11 was the most frequent mutation site (44.7%) followed by exon 9 (21.1%) equally characterizing UV-induced common histotypes and ALM tumors. In mucosal melanoma exon 9 was the most frequently involved exon followed by exon 13 and 17. KIT mutation hotspots were identified in exon 9 (c482/491/492), in exon 11 (c559,c572, c570), in exon 13 (c642), in exon 17 (c822) and in exon 18 (c853). The relatively high KIT mutation rate in cutaneous melanoma in this central-European cohort justifies regular testing of this molecular target in this entity, not only in mucosal variants.

Immunologic and immunogenomic aspects of tumor progression

Tumor progression to metastatic disease is characterized by continuous genetic alterations due to instability of the genome. Immune sensitivity was found to be linked to tumor mutational burden (TMB) and the resulting amount of neoantigens. However, APOBEC activity resulting in increase in TMB causes immune evasion. On the other hand, clonal or acquired genetic loss of HLA class I also hampers immune sensitivity of tumors. Rare amplification of the PD-L1 gene in cancers may render them sensitive to immune checkpoint inhibitors but involvement of broader regions of chromosome 9p may ultimately lead again to immune evasion due to inactivation of the IFN-γ signaling pathway. Such genetic changes may occur not only in the primary tumor but at any phase of progression: in lymphatic as well as in visceral metastases. Accordingly, it is rational to monitor these changes continuously during disease progression similar to target therapies. Moreover, beside temporal variability, genomic features of tumors such as mutation profiles, as well as the tumor immune microenvironment also show considerable inter- and intratumoral spatial heterogeneity, suggesting the necessity of multiple sampling in biomarker studies.

Gene expression and promoter methylation of angiogenic and lymphangiogenic factors as prognostic markers in melanoma

The high mortality rate of melanoma is broadly associated with its metastatic potential. Tumor cell dissemination is strictly dependent on vascularization; therefore, angiogenesis and lymphangiogenesis play an essential role in metastasis. Hence, a better understanding of the players of tumor vascularization and establishing them as new molecular biomarkers might help to overcome the poor prognosis of melanoma patients. Here, we further characterized a linear murine model of melanoma progression and showed that the aggressiveness of melanoma cells is closely associated with high expression of angiogenic factors, such as Vegfc, Angpt2, and Six1, and that blockade of the vascular endothelial growth factor pathway by the inhibitor axitinib abrogates their tumorigenic potential in vitro and in the in vivo chicken chorioallantoic membrane assay. Furthermore, analysis of The Cancer Genome Atlas data revealed that the expression of the angiogenic factor ANGPT2 (P‐value = 0.044) and the lymphangiogenic receptor VEGFR‐3 (P‐value = 0.002) were independent prognostic factors of overall survival in melanoma patients. Enhanced reduced representation bisulfite sequencing‐based methylome profiling revealed for the first time a link between abnormal VEGFC, ANGPT2, and SIX1 gene expression and promoter hypomethylation in melanoma cells. In patients, VEGFC (P‐value = 0.031), ANGPT2 (P‐value < 0.001), and SIX1 (P‐value = 0.009) promoter hypomethylation were independent prognostic factors of shorter overall survival. Hence, our data suggest that these angio‐ and lymphangiogenesis factors are potential biomarkers of melanoma prognosis. Moreover, these findings strongly support the applicability of our melanoma progression model to unravel new biomarkers for this aggressive human disease.

The role of lipid signaling in the progression of malignant melanoma

In the past decades, a vast amount of data accumulated on the role of lipid signaling pathways in the progression of malignant melanoma, the most metastatic/aggressive human cancer type. Genomic studies identified that PTEN loss is the leading factor behind the activation of the PI3K-signaling pathway in melanoma, mutations of which are one of the main resistance mechanisms behind target therapy failures. On the other hand, illegitimate expressions of megakaryocytic genes p12-lipoxyganse, cyclooxygenase-2, and phosphodiestherase-2/autotaxin (ATX) are mostly involved in the regulation of motility signaling in melanoma through various G-protein-coupled bioactive lipid receptors. Furthermore, endocannabinoid signaling can also be a novel paracrine survival factor in melanoma. Last but not least, prenylation inhibitors acting even on mutated small GTP-ases, such as NRAS of melanoma may offer novel therapeutic opportunities. As regards melanoma, the most effective therapy nowadays is immunotherapy, with the resistance mechanisms also possibly involving the lipid signaling activities of melanoma cells, which further supports the idea of their being therapeutic targets.

New Insights into the Runt Domain of RUNX2 in Melanoma Cell Proliferation and Migration

The mortality rate for malignant melanoma (MM) is very high, since it is highly invasive and resistant to chemotherapeutic treatments. The modulation of some transcription factors affects cellular processes in MM. In particular, a higher expression of the osteogenic master gene RUNX2 has been reported in melanoma cells, compared to normal melanocytes. By analyzing public databases for recurrent RUNX2 genetic and epigenetic modifications in melanoma, we found that the most common RUNX2 genetic alteration that exists in transcription upregulation is, followed by genomic amplification, nucleotide substitution and multiple changes. Additionally, altered RUNX2 is involved in unchecked pathways promoting tumor progression, Epithelial Mesenchymal Transition (EMT), and metastasis. In order to investigate further the role of RUNX2 in melanoma development and to identify a therapeutic target, we applied the CRISPR/Cas9 technique to explore the role of the RUNT domain of RUNX2 in a melanoma cell line. RUNT-deleted cells showed reduced proliferation, increased apoptosis, and reduced EMT features, suggesting the involvement of the RUNT domain in different pathways. In addition, del-RUNT cells showed a downregulation of genes involved in migration ability. In an in vivo zebrafish model, we observed that wild-type melanoma cells migrated in 81% of transplanted fishes, while del-RUNT cells migrated in 58%. All these findings strongly suggest the involvement of the RUNT domain in melanoma metastasis and cell migration and indicate RUNX2 as a prospective target in MM therapy.

BRAF Gene Copy Number and Mutant Allele Frequency Correlate with Time to Progression in Metastatic Melanoma Patients Treated with MAPK Inhibitors

Metastatic melanoma is characterized by complex genomic alterations, including a high rate of mutations in driver genes and widespread deletions and amplifications encompassing various chromosome regions. Among them, chromosome 7 is frequently gained in BRAF-mutant melanoma, inducing a mutant allele-specific imbalance. Although BRAF amplification is a known mechanism of acquired resistance to therapy with MAPK inhibitors, it is still unclear if BRAF copy-number variation and BRAF mutant allele imbalance at baseline can be associated with response to treatment. In this study, we used a multimodal approach to assess BRAF copy number and mutant allele frequency in pretreatment melanoma samples from 46 patients who received MAPK inhibitor-based therapy, and we analyzed the association with progression-free survival. We found that 65% patients displayed BRAF gains, often supported by chromosome 7 polysomy. In addition, we observed that 64% patients had a balanced BRAF-mutant/wild-type allele ratio, whereas 14% and 23% patients had low and high BRAF mutant allele frequency, respectively. Notably, a significantly higher risk of progression was observed in patients with a diploid BRAF status versus those with BRAF gains [HR, 2.86; 95% confidence interval (CI), 1.29-6.35; P = 0.01] and in patients with low percentage versus those with a balanced BRAF mutant allele percentage (HR, 4.54; 95% CI, 1.33-15.53; P = 0.016). Our data suggest that quantitative analysis of the BRAF gene could be useful to select the melanoma patients who are most likely to benefit from therapy with MAPK inhibitors. Mol Cancer Ther; 17(6); 1332-40. ©2018 AACR.

Neoplastic Multifocal Skin Lesions: Biology, Etiology, and Targeted Therapies for Nonmelanoma Skin Cancers

Neoplastic skin lesions are multifocal, diffuse skin infiltrations of particular relevance in the differential diagnosis of ulcerative, nodular, or crusting skin lesions. Nonmelanoma skin cancers (NMSCs), namely, basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and also actinic keratosis (AK), are the most common malignant tumors in humans. BCCs do not proliferate rapidly and most of the times do not metastasize, while SCCs are more infiltrative, metastatic, and destructive. AKs are precursor lesions of cutaneous SCCs. The classical therapy of NMSCs makes use of photodynamic therapy associated with chemotherapeutics. With improved understanding of the pathological mechanisms of tumor initiation, progression, and differentiation, a case is made towards the use of targeted chemotherapy with the intent to reduce the cytotoxicity of classical treatments. The present review aims to describe the current state of the art on the knowledge of NMSC, including its risks factors, oncogenes, and skin carcinogenesis, discussing the classical therapy against new therapeutic options.

Intracranial Erdheim-Chester Disease Mimicking Parafalcine Meningioma: Report of Two Cases and Review of the Literature

BACKGROUND

Erdheim-Chester disease (ECD) is a rare, non-Langerhans cell histiocytosis that typically occurs in middle-aged patients. It is usually characterized by multifocal osteosclerotic lesions of the long-bones, however many cases have extraskeletal involvement. Central nervous system (CNS) involvement is common, but isolated CNS involvement at presentation has rarely been reported.

CASE DESCRIPTION

Here we report two cases of dural-based ECD mimicking meningioma on imaging with no other identified sites of disease.

CONCLUSION

ECD is a rare disease, with isolated CNS involvement reported only a few times in the literature. The significance of this presentation requires additional study and long-term follow up.

Combining forces: the promise and peril of synergistic immune checkpoint blockade and targeted therapy in metastatic melanoma

Both immune checkpoint inhibitors and molecularly targeted agents have dramatically improved clinical outcomes for patients with metastatic melanoma. These two therapeutic approaches harness distinct mechanistic pathways-on the one hand, monoclonal antibodies against the immune checkpoints CTLA-4 and PD-1/PD-L1 stimulate the T cell mediated host immune response, while targeted inhibitors of the proto-oncogenes BRAF and MEK disrupt constitutive kinase activity responsible for tumor growth. The prospect of combining these two treatment modalities has been proposed as a potential way to increase overall response rate, extend durability of the anti-tumor response, and circumvent the immune-mediated resistance to targeted therapy. This review explores the preclinical rationale-building upon a wealth of in vitro and in vivo studies-for improved anti-tumor efficacy from combined immune checkpoint inhibition and targeted therapy. In the process, we detail the early clinical trials that have assessed the compatibility of combining these two therapies and the unexpected challenges faced from studies showing increased toxicity from these regimens. Ultimately, with more clinical data expected to mature and accrue in the near future, we elucidate a potentially novel and promising strategy for patients with advanced melanoma.

The impact of melanoma genetics on treatment response and resistance in clinical and experimental studies

Recent attempts to characterize the melanoma mutational landscape using high-throughput sequencing technologies have identified new genes and pathways involved in the molecular pathogenesis of melanoma. Apart from mutated BRAF, NRAS, and KIT, a series of new recurrently mutated candidate genes with impact on signaling pathways have been identified such as NF1, PTEN, IDH1, RAC1, ARID2, and TP53. Under targeted treatment using BRAF and MEK1/2 inhibitors either alone or in combination, a majority of patients experience recurrences, which are due to different genetic mechanisms such as gene amplifications of BRAF or NRAS, MEK1/2 and PI3K mutations. In principle, resistance mechanisms converge on two signaling pathways, MAPK and PI3K-AKT-mTOR pathways. Resistance may be due to small subsets of resistant cells within a heterogeneous tumor mass not identified by sequencing of the bulk tumor. Future sequencing studies addressing tumor heterogeneity, e.g., by using single-cell sequencing technology, will most likely improve this situation. Gene expression patterns of metastatic lesions were also shown to predict treatment response, e.g., a MITF-low/NF-κB-high melanoma phenotype is resistant against classical targeted therapies. Finally, more recent treatment approaches using checkpoint inhibitors directed against PD-1 and CTLA-4 are very effective in melanoma and other tumor entities. Here, the mutational and neoantigen load of melanoma lesions may help to predict treatment response. Taken together, the new sequencing, molecular, and bioinformatic technologies exploiting the melanoma genome for treatment decisions have significantly improved our understanding of melanoma pathogenesis, treatment response, and resistance for either targeted treatment or immune checkpoint blockade.

Precision medicine driven by cancer systems biology

Molecular insights from genome and systems biology are influencing how cancer is diagnosed and treated. We critically evaluate big data challenges in precision medicine. The melanoma research community has identified distinct subtypes involving chronic sun-induced damage and the mitogen-activated protein kinase driver pathway. In addition, despite low mutation burden, non-genomic mitogen-activated protein kinase melanoma drivers are found in membrane receptors, metabolism, or epigenetic signaling with the ability to bypass central mitogen-activated protein kinase molecules and activating a similar program of mitogenic effectors. Mutation hotspots, structural modeling, UV signature, and genomic as well as non-genomic mechanisms of disease initiation and progression are taken into consideration to identify resistance mutations and novel drug targets. A comprehensive precision medicine profile of a malignant melanoma patient illustrates future rational drug targeting strategies. Network analysis emphasizes an important role of epigenetic and metabolic master regulators in oncogenesis. Co-occurrence of driver mutations in signaling, metabolic, and epigenetic factors highlights how cumulative alterations of our genomes and epigenomes progressively lead to uncontrolled cell proliferation. Precision insights have the ability to identify independent molecular pathways suitable for drug targeting. Synergistic treatment combinations of orthogonal modalities including immunotherapy, mitogen-activated protein kinase inhibitors, epigenetic inhibitors, and metabolic inhibitors have the potential to overcome immune evasion, side effects, and drug resistance.

Somatic Mutation Analysis of Human Cancers: Challenges in Clinical Practice

Somatic mutation analysis of human cancers has become the standard of practice. Whether screening for single gene variants or sequencing hundreds of cancer-related genes, this genomic information is the basis for precision medicine initiatives in oncology. Genomic profiling results in information that allows oncologists to make a more educated selection of appropriate therapeutic strategies that more often combine traditional cytotoxic chemotherapy and radiation with novel targeted therapies. Here we discuss the nuances of implementing somatic mutation testing in a clinical setting.

Concurrent BRAF and PTEN mutations in melanoma of unknown origin presenting as a breast mass

BACKGROUND

Metastases represent a small percentage of the malignancies affecting the breast, and only 5% of melanomas originate from non-cutaneous sites. Multiple genetic aberrations have been associated with the development of melanocytic lesions, including BRAF V600E mutation. Mutations in PTEN gene have also been related to the pathogenesis of multiple malignancies.

PURPOSE/METHOD

This is the case of a 28-year-old female who presented with a tender, palpable mass in the upper outer quadrant of the right breast. Ultrasound showed a 1-cm solid mass, initially diagnosed as invasive ductal carcinoma on biopsy. During pre-operative workup, a second mass was identified and biopsied. Immunohistochemical stains performed on the second mass biopsy demonstrated that the neoplastic cells were positive for cytokeratin AE1/3, pan-melanoma, tyrosinase, and SOX-10 and negative for CK7, CAM5.2, and GATA-3. Subsequent workup showed widespread metastatic disease involving the liver, lungs, bones, and brain. The brain metastasis tested positive for BRAF p.V600E and PTEN p.R130Efs*4 mutations. Thorough skin and eye examination did not reveal a primary melanoma.

CONCLUSION

Only few reports have been published of melanoma presenting as a breast mass. This is an interesting case due to the clinical presentation, diagnostic challenges, and genetic mutations profile.

Management of skin adverse events associated with immune checkpoint inhibitors in patients with melanoma: A nursing perspective

PURPOSE

Immune checkpoint inhibitors are associated with a unique immune-related side effect profile that requires prompt recognition and management. Skin toxicities are the most common, and often earliest occurring, drug-related adverse events (AEs) of any grade observed upon treatment with these agents. The purpose of this review is to provide practical guidance on the identification and treatment of skin AEs associated with the immune checkpoint inhibitors (ipilimumab, nivolumab, and pembrolizumab) from a nursing perspective, and demonstrate hands-on application of the guidance using relevant patient case studies.

DATA SOURCES

Data for drug-related skin AEs were summarized from phase 3 nivolumab and nivolumab + ipilimumab trials and phase 2 and 3 pembrolizumab trials. Patient case studies were provided by the lead (M.T.) and senior (J.N.C.) authors.

CONCLUSIONS

The recommendations presented here, based on accumulated clinical trial and clinical practice experience are consistent with established treatment guidelines and reach beyond established guidelines and recommendations for the management of AEs associated with immune checkpoint inhibitors.

IMPLICATIONS FOR PRACTICE

The practical treatment guidance presented here may help familiarize medical teams with the recognition and management of skin AEs associated with these recently approved agents. The enclosed recommendations may contribute to optimized treatment through awareness of typical time to onset and clinical presentation, knowledge of management options, and appropriate application of treatment.

Fasting boosts sensitivity of human skin melanoma to cisplatin-induced cell death

Melanoma is one of leading cause of tumor death worldwide. Anti-cancer strategy includes combination of different chemo-therapeutic agents as well as radiation; however these treatments have limited efficacy and induce significant toxic effects on healthy cells. One of most promising novel therapeutic approach to cancer therapy is the combination of anti-cancer drugs with calorie restriction. Here we investigated the effect Cisplatin (CDDP), one of the most potent chemotherapeutic agent used to treat tumors, in association with fasting in wild type and mutated BRAFV600E melanoma cell lines. Here we show that nutrient deprivation can consistently enhance the sensitivity of tumor cells to cell death induction by CDDP, also of those malignancies particularly resistant to any treatment, such as oncogenic BRAF melanomas. Mechanistic studies revealed that the combined therapy induced cell death is characterized by ROS accumulation and ATF4 in the absence of ER-stress. In addition, we show that autophagy is not involved in the enhanced sensitivity of melanoma cells to combined CDDP/EBSS-induced apoptosis. While, the exposure to 2-DG further enhanced the apoptotic rate observed in SK Mel 28 cells upon treatment with both CDDP and EBSS.

Computational modeling in melanoma for novel drug discovery

INTRODUCTION

There is a growing body of evidence highlighting the applications of computational modeling in the field of biomedicine. It has recently been applied to the in silico analysis of cancer dynamics. In the era of precision medicine, this analysis may allow the discovery of new molecular targets useful for the design of novel therapies and for overcoming resistance to anticancer drugs. According to its molecular behavior, melanoma represents an interesting tumor model in which computational modeling can be applied. Melanoma is an aggressive tumor of the skin with a poor prognosis for patients with advanced disease as it is resistant to current therapeutic approaches.

AREAS COVERED

This review discusses the basics of computational modeling in melanoma drug discovery and development. Discussion includes the in silico discovery of novel molecular drug targets, the optimization of immunotherapies and personalized medicine trials.

EXPERT OPINION

Mathematical and computational models are gradually being used to help understand biomedical data produced by high-throughput analysis. The use of advanced computer models allowing the simulation of complex biological processes provides hypotheses and supports experimental design. The research in fighting aggressive cancers, such as melanoma, is making great strides. Computational models represent the key component to complement these efforts. Due to the combinatorial complexity of new drug discovery, a systematic approach based only on experimentation is not possible. Computational and mathematical models are necessary for bringing cancer drug discovery into the era of omics, big data and personalized medicine.

Estrogen Receptor β in Melanoma: From Molecular Insights to Potential Clinical Utility

Cutaneous melanoma is an aggressive tumor; its incidence has been reported to increase fast in the past decades. Melanoma is a heterogeneous tumor, with most patients harboring mutations in the BRAF or NRAS oncogenes, leading to the overactivation of the MAPK/ERK and PI3K/Akt pathways. The current therapeutic approaches are based on therapies targeting mutated BRAF and the downstream pathway, and on monoclonal antibodies against the immune checkpoint blockade. However, treatment resistance and side effects are common events of these therapeutic strategies. Increasing evidence supports that melanoma is a hormone-related cancer. Melanoma incidence is higher in males than in females, and females have a significant survival advantage over men. Estrogens exert their effects through estrogen receptors (ERα and ERβ) that affect cancer growth in an opposite way: ERα is associated with a proliferative action and ERβ with an anticancer effect. ERβ is the predominant ER in melanoma, and its expression decreases in melanoma progression, supporting its role as a tumor suppressor. Thus, ERβ is now considered as an effective molecular target for melanoma treatment. 17β-estradiol was reported to inhibit melanoma cells proliferation; however, clinical trials did not provide the expected survival benefits. In vitro studies demonstrate that ERβ ligands inhibit the proliferation of melanoma cells harboring the NRAS (but not the BRAF) mutation, suggesting that ERβ activation might impair melanoma development through the inhibition of the PI3K/Akt pathway. These data suggest that ERβ agonists might be considered as an effective treatment strategy, in combination with MAPK inhibitors, for NRAS mutant melanomas. In an era of personalized medicine, pretreatment evaluation of the expression of ER isoforms together with the concurrent oncogenic mutations should be considered before selecting the most appropriate therapeutic intervention. Natural compounds that specifically bind to ERβ have been identified. These phytoestrogens decrease the proliferation of melanoma cells. Importantly, these effects are unrelated to the oncogenic mutations of melanomas, suggesting that, in addition to their ERβ activating function, these compounds might impair melanoma development through additional mechanisms. A better identification of the role of ERβ in melanoma development will help increase the therapeutic options for this aggressive pathology.