Treatment of NRAS-mutant melanoma

Isomer-sourced structure iteration methods for in silico development of inhibitors: Inducing GTP-bound NRAS-Q61 oncogenic mutations to an "off-like" state

The NRAS-mutant subset of melanoma represent some of the most aggressive and deadliest types associated with poor overall survival. Unfortunately, for more than 40 years, no therapeutic agent directly targeting NRAS mutations has been clinically approved. In this work, based on microsecond scale molecular dynamics simulations, the effect of Q61 mutations on NRAS conformational characteristics is revealed at the atomic level. The GTP-bound NRAS-Q61R and Q61K mutations show a specific targetable pocket between Switch-II and α-helix 3 whereas the NRAS-Q61L non-polar mutation category shows a different targetable pocket. Moreover, a new isomer-sourced structure iteration method has been developed for the in silico design of potential inhibitor prototypes for oncogenes. We show the possibility of a designed prototype HM-387 to target activated NRAS-Q61R and that it can gradually induce the transition from the activated NRAS-Q61R to an "off-like" state.

Assessing melanoma prognosis: the interplay between patient profiles, survival, and BRAF, NRAS, KIT, and TWT mutations in a retrospective multi-study analysis

The incidence and prevalence of melanoma are increasing globally, presenting a significant public health concern. The main genetic drivers of melanoma include BRAF, NRAS, KIT and triple wild-type (TWT) mutations. Little is known about the effects of these mutations on outcomes in terms of demographics and patient characteristics. We examined differences in melanoma mortality risk and mutation count across mutation type and patient disease profile. We extrapolated primary melanoma patient data from 14 studies via the cBioportal database. Patients were divided into demographic groups and classified according to BRAF, NRAS, KIT and TWT mutation status. Analyses included two-sample Student t -test and two-way analysis of variance tests analysis with Tukey's post hoc test. Survival outcomes were compared via Kaplan-Meier curve and Cox regression. NRAS-mutated patients exhibited decreased overall survival compared to BRAF-mutated patients. Male patients had higher mutation counts across all gene groups than females, with the fewest TWT mutations in comparison to BRAF, NRAS and KIT mutations. Males also exhibited increased mortality risk for NRAS, KIT and TWT mutations compared to BRAF mutations. An unknown primary melanoma was associated with increased mortality risk across all gene groups. NRAS-mutated acral melanoma patients had an increased mortality risk compared to NRAS-mutated cutaneous melanoma patients. Older patients had a higher mortality risk than younger patients. Patients with heavier versus lower weights had lower mortality risk, which was more pronounced for BRAF-mutated patients. These relationships highlight the importance of demographic and pathologic relationships to aid in risk assessment and personalize treatment plans.

Peroxiredoxin-2 represses NRAS-mutated melanoma cells invasion by modulating EMT markers

The second most common mutation in melanoma occurs in NRAS oncogene, being a more aggressive disease that has no effective approved treatment. Besides, cellular plasticity limits better outcomes of the advanced and therapy-resistant patients. Peroxiredoxins (PRDXs) control cellular processes through direct hydrogen peroxide oxidation or by redox-relaying processes. Here, we demonstrated that PRDX2 could act as a modulator of multiple EMT markers in NRAS-mutated melanomas. PRDX2 knockdown lead to phenotypic changes towards invasion in human reconstructed skin and the treatment with a PRDX mimetic (gliotoxin), decreased migration in PRDX2-deficient cells. We also confirmed the favorable clinical outcome of patients expressing PRDX2 in a large primary melanoma cohort. This study contributes to our knowledge about genes involved in phenotype switching and opens a new perspective for PRDX2 as a biomarker and target in NRAS-mutated melanomas.

IκBα kinase inhibitor BAY 11-7082 promotes anti-tumor effect in RAS-driven cancers

BACKGROUND

Oncogenic mutations in the RAS gene are associated with uncontrolled cell growth, a hallmark feature contributing to tumorigenesis. While diverse therapeutic strategies have been diligently applied to treat RAS-mutant cancers, successful targeting of the RAS gene remains a persistent challenge in the field of cancer therapy. In our study, we discover a promising avenue for addressing this challenge.

METHODS

In this study, we tested the viability of several cell lines carrying oncogenic NRAS, KRAS, and HRAS mutations upon treatment with IkappaBalpha (IκBα) inhibitor BAY 11-7082. We performed both cell culture-based viability assay and in vivo subcutaneous xenograft-based assay to confirm the growth inhibitory effect of BAY 11-7082. We also performed large RNA sequencing analysis to identify differentially regulated genes and pathways in the context of oncogenic NRAS, KRAS, and HRAS mutations upon treatment with BAY 11-7082.

RESULTS

We demonstrate that oncogenic NRAS, KRAS, and HRAS activate the expression of IκBα kinase. BAY 11-7082, an inhibitor of IκBα kinase, attenuates the growth of NRAS, KRAS, and HRAS mutant cancer cells in cell culture and in mouse model. Mechanistically, BAY 11-7082 inhibitor treatment leads to suppression of the PI3K-AKT signaling pathway and activation of apoptosis in all RAS mutant cell lines. Additionally, we find that BAY 11-7082 treatment results in the downregulation of different biological pathways depending upon the type of RAS protein that may also contribute to tumor growth inhibition.

CONCLUSION

Our study identifies BAY 11-7082 to be an efficacious inhibitor for treating RAS oncogene (HRAS, KRAS, and NRAS) mutant cancer cells. This finding provides new therapeutic opportunity for effective treatment of RAS-mutant cancers.

The Pan-RAF-MEK Nondegrading Molecular Glue NST-628 Is a Potent and Brain-Penetrant Inhibitor of the RAS-MAPK Pathway with Activity across Diverse RAS- and RAF-Driven Cancers

Alterations in the RAS-MAPK signaling cascade are common across multiple solid tumor types and are a driver for many cancers. NST-628 is a potent pan-RAF-MEK molecular glue that prevents the phosphorylation and activation of MEK by RAF, overcoming the limitations of traditional RAS-MAPK inhibitors and leading to deep durable inhibition of the pathway. Cellular, biochemical, and structural analyses of RAF-MEK complexes show that NST-628 engages all isoforms of RAF and prevents the formation of BRAF-CRAF heterodimers, a differentiated mechanism from all current RAF inhibitors. With a potent and durable inhibition of the RAF-MEK signaling complex as well as high intrinsic permeability into the brain, NST-628 demonstrates broad efficacy in cellular and patient-derived tumor models harboring diverse MAPK pathway alterations, including orthotopic intracranial models. Given its functional and pharmacokinetic mechanisms that are differentiated from previous therapies, NST-628 is positioned to make an impact clinically in areas of unmet patient need. Significance: This study introduces NST-628, a molecular glue having differentiated mechanism and drug-like properties. NST-628 treatment leads to broad efficacy with high tolerability and central nervous system activity across multiple RAS- and RAF-driven tumor models. NST-628 has the potential to provide transformative clinical benefits as both monotherapy and vertical combination anchor.

Precision Oncology in Melanoma and Skin Cancer Surgery

There has been perhaps no greater advance in the prognosis of solid tumors in the last decade than for patients with metastatic melanoma. This is due to significant improvements in treatment based on two key components of melanoma tumor biology (1) the identification of driver mutations with therapeutic potential and (2) the mechanistic understanding of a tumor-specific immune response. With breakthrough findings in such a relatively short period of time, the treatment of patients with metastatic melanoma has become intensely personalized.

Consistency between Primary Uterine Corpus Malignancies and Their Corresponding Patient-Derived Xenograft Models

Patient-derived xenograft (PDX) models retain the characteristics of tumors and are useful tools for personalized therapy and translational research. In this study, we aimed to establish PDX models for uterine corpus malignancies (UC-PDX) and analyze their similarities. Tissue fragments obtained from 92 patients with uterine corpus malignancies were transplanted subcutaneously into immunodeficient mice. Histological and immunohistochemical analyses were performed to compare tumors of patients with PDX tumors. DNA and RNA sequencing were performed to validate the genetic profile. Furthermore, the RNA in extracellular vesicles (EVs) extracted from primary and PDX tumors was analyzed. Among the 92 cases, 52 UC-PDX models were established, with a success rate of 56.5%. The success rate depended on tumor histology and staging. The pathological and immunohistochemical features of primary and PDX tumors were similar. DNA sequencing revealed similarities in gene mutations between the primary and PDX tumors. RNA sequencing showed similarities in gene expressions between primary and PDX tumors. Furthermore, the RNA profiles of the EVs obtained from primary and PDX tumors were similar. As UC-PDX retained the pathological and immunohistochemical features and gene profiles of primary tumors, they may provide a platform for developing personalized medicine and translational research.

Lack of Influence of Non-Overlapping Mutations in BRAF, NRAS, or NF1 on 12-Month Best Objective Response and Long-Term Survival after Checkpoint Inhibitor-Based Treatment for Metastatic Melanoma

BACKGROUND

Non-overlapping somatic mutations in BRAF, NRAS, or NF1 genes occur in 85% of metastatic melanoma patients. It is not known whether these mutations affect immunotherapy outcome.

MATERIALS AND METHODS

Next-Gen sequencing of 324 oncogenes was performed in 73 metastatic melanoma patients. A retrospective review of immunotherapy outcome was performed.

RESULTS

BRAF fusions/internal rearrangements, BRAF V600E, NRAS, NF1 mutations, and triple-negative genotypes occurred in 6.9%, 30.1%, 17.8%, 32.9%, and 12.3% of patients, respectively. Median potential follow-up was 41.0 months. Patients with BRAF fusion/rearrangement had decreased progression-free and overall survival (p = 0.015). The other genotypes each had similar progression-free and overall survival. Patients who achieved a complete best objective response at 12 months (n = 36, 49.3%) were found to have significantly improved survival compared those who failed to achieve remissions (n = 37, 50.7%, p < 0.001).

CONCLUSIONS

The most important determinant of long-term survival was achievement of a complete response by 12 months following immunotherapy. PR and SD were not a stable type of response and generally resulted in progression and death from melanoma. Rare patients with BRAF fusions or rearrangements had decreased progression-free and overall survival following initial immunotherapy. Other BRAF, NRAS, or NF1 mutations were not associated with significant differences in outcome.

Investigating the NRAS 5' UTR as a target for small molecules

Neuroblastoma RAS (NRAS) is an oncogene that is deregulated and highly mutated in cancers including melanomas and acute myeloid leukemias. The 5' untranslated region (UTR) (5' UTR) of the NRAS mRNA contains a G-quadruplex (G4) that regulates translation. Here we report a novel class of small molecule that binds to the G4 structure located in the 5' UTR of the NRAS mRNA. We used a small molecule microarray screen to identify molecules that selectively bind to the NRAS-G4 with submicromolar affinity. One compound inhibits the translation of NRAS in vitro but showed only moderate effects on the NRAS levels in cellulo. Rapid Amplification of cDNA Ends and RT-PCR analysis revealed that the predominant NRAS transcript does not possess the G4 structure. Thus, although NRAS transcripts lack a G4 in many cell lines the concept of targeting folded regions within 5' UTRs to control translation remains a highly attractive strategy.

The role of mitochondria in the resistance of melanoma to PD-1 inhibitors

Malignant melanoma is one of the most common tumours and has the highest mortality rate of all types of skin cancers worldwide. Traditional and novel therapeutic approaches, including surgery, targeted therapy and immunotherapy, have shown good efficacy in the treatment of melanoma. At present, the mainstay of treatment for melanoma is immunotherapy combined with other treatment strategies. However, immune checkpoint inhibitors, such as PD-1 inhibitors, are not particularly effective in the clinical treatment of patients with melanoma. Changes in mitochondrial function may affect the development of melanoma and the efficacy of PD-1 inhibitors. To elucidate the role of mitochondria in the resistance of melanoma to PD-1 inhibitors, this review comprehensively summarises the role of mitochondria in the occurrence and development of melanoma, targets related to the function of mitochondria in melanoma cells and changes in mitochondrial function in different cells in melanoma resistant to PD-1 inhibitors. This review may help to develop therapeutic strategies for improving the clinical response rate of PD-1 inhibitors and prolonging the survival of patients by activating mitochondrial function in tumour and T cells.

Therapeutic targeting of anoikis resistance in cutaneous melanoma metastasis

The acquisition of resistance to anoikis, the cell death induced by loss of adhesion to the extracellular matrix, is an absolute requirement for the survival of disseminating and circulating tumour cells (CTCs), and for the seeding of metastatic lesions. In melanoma, a range of intracellular signalling cascades have been identified as potential drivers of anoikis resistance, however a full understanding of the process is yet to be attained. Mechanisms of anoikis resistance pose an attractive target for the therapeutic treatment of disseminating and circulating melanoma cells. This review explores the range of small molecule, peptide and antibody inhibitors targeting molecules involved in anoikis resistance in melanoma, and may be repurposed to prevent metastatic melanoma prior to its initiation, potentially improving the prognosis for patients.

Inhibition of the MNK1/2-eIF4E Axis Augments Palbociclib-Mediated Antitumor Activity in Melanoma and Breast Cancer

Aberrant cell-cycle progression is characteristic of melanoma, and CDK4/6 inhibitors, such as palbociclib, are currently being tested for efficacy in this disease. Despite the promising nature of CDK4/6 inhibitors, their use as single agents in melanoma has shown limited clinical benefit. Herein, we discovered that treatment of tumor cells with palbociclib induces the phosphorylation of the mRNA translation initiation factor eIF4E. When phosphorylated, eIF4E specifically engenders the translation of mRNAs that code for proteins involved in cell survival. We hypothesized that cancer cells treated with palbociclib use upregulated phosphorylated eIF4E (phospho-eIF4E) to escape the antitumor benefits of this drug. Indeed, we found that pharmacologic or genetic disruption of MNK1/2 activity, the only known kinases for eIF4E, enhanced the ability of palbociclib to decrease clonogenic outgrowth. Moreover, a quantitative proteomics analysis of melanoma cells treated with combined MNK1/2 and CDK4/6 inhibitors showed downregulation of proteins with critical roles in cell-cycle progression and mitosis, including AURKB, TPX2, and survivin. We also observed that palbociclib-resistant breast cancer cells have higher basal levels of phospho-eIF4E, and that treatment with MNK1/2 inhibitors sensitized these palbociclib-resistant cells to CDK4/6 inhibition. In vivo we demonstrate that the combination of MNK1/2 and CDK4/6 inhibition significantly increases the overall survival of mice compared with either monotherapy. Overall, our data support MNK1/2 inhibitors as promising drugs to potentiate the antineoplastic effects of palbociclib and overcome therapy-resistant disease.

Multiple predictive biomarker testing in melanoma: Another challenge in identifying the optimal approach on cytological samples

BACKGROUND

The management of cutaneous melanoma has changed dramatically in recent years thanks to the development of tyrosine kinase and immune-checkpoint inhibitors (ICIs). Thus, multiple biomarker testing is becoming ever more important for the identification of patients who are potentially eligible for these treatments. One reliable approach to the molecular evaluation of metastatic melanoma is fine needle cytology (FNC). To examine the utility of this approach for assessing PD-L1 expression levels, we evaluated the cellular adequacy of residual cell block (CB) material from metastatic melanomas that were previously tested for BRAF and NRAS mutations.

METHODS

We retrieved from our internal archives a series of FNC samples of metastatic melanoma that had been subjected to molecular testing on residual CB material or a dedicated needle rinse between January 2016 and July 2022. Real-time polymerase chain reaction was used to assess BRAF and NRAS status, and an SP263 assay was employed to ascertain PD-L1 expression levels.

RESULTS

Overall, n = 19 cases were selected. Of these, 11 (57.9%) cases revealed a BRAF exon 15 p.V600E mutation, one case (5.3%) revealed NRAS mutation, and seven cases (36.8%) showed no mutations. Regarding PD-L1 assessment, 16/19 (84.2%) cases were deemed adequate, meaning they contained at least 100 viable cells.

CONCLUSIONS

We highlighted the feasibility of assessing PD-L1 expression levels in residual CB material from metastatic melanomas previously tested for BRAF and NRAS mutations. Moreover, we pointed out that FNC needle rinses may be an alternative source of nucleic acids for molecular testing, preserving CB material for immunocytochemistry evaluation.

Case report: Later onset of NRAS-mutant metastatic melanoma in a patient with a partially-excised giant congenital melanocytic nevus

Despite recent advances in treatment and surveillance, metastatic melanoma still carries a poor prognosis. Large/giant congenital melanocytic nevi (CMNs) constitute a known risk factor for the condition, with the greatest risk for malignant transformation thought to be during childhood (median age at diagnosis of 3 years in a previous cohort). Herein, we present the case of a 30-year-old male who, after undergoing multiple excision/grafting procedures for a giant CMN as a child, was diagnosed with an NRAS-mutant, MDM2-amplified metastatic melanoma more than 20 years later. Response to ipilimumab/nivolumab immunotherapy, cisplatin/vinblastine/temozolomide chemotherapy, and nivolumab/relatlimab immunotherapy was poor. This case highlights the importance of lifetime monitoring with once-yearly dermatological examination (including lymph node palpation) in large/giant CMN patients, as well as the need for further clinical trials evaluating novel therapies for NRAS-mutant melanoma.

Treatment of Metastatic Melanoma with a Combination of Immunotherapies and Molecularly Targeted Therapies

Simple Summary

Immunotherapies and molecularly targeted therapies have drastically changed the therapeutic approach for unresectable advanced or metastatic melanoma. The majority of melanoma patients have benefitted from these therapies; however, some patients acquire resistance to them. Novel combinations of immunotherapies and molecularly targeted therapies may be more efficient in treating these patients. In this review, we discuss various combination therapies under pre-clinical and clinical development which can reduce toxicity, enhance efficacy, and prevent recurrences in patients with metastatic melanoma.

Abstract

Melanoma possesses invasive metastatic growth patterns and is one of the most aggressive types of skin cancer. In 2021, it is estimated that 7180 deaths were attributed to melanoma in the United States alone. Once melanoma metastasizes, traditional therapies are no longer effective. Instead, immunotherapies, such as ipilimumab, pembrolizumab, and nivolumab, are the treatment options for malignant melanoma. Several biomarkers involved in tumorigenesis have been identified as potential targets for molecularly targeted melanoma therapy, such as tyrosine kinase inhibitors (TKIs). Unfortunately, melanoma quickly acquires resistance to these molecularly targeted therapies. To bypass resistance, combination treatment with immunotherapies and single or multiple TKIs have been employed and have been shown to improve the prognosis of melanoma patients compared to monotherapy. This review discusses several combination therapies that target melanoma biomarkers, such as BRAF, MEK, RAS, c-KIT, VEGFR, c-MET and PI3K. Several of these regimens are already FDA-approved for treating metastatic melanoma, while others are still in clinical trials. Continued research into the causes of resistance and factors influencing the efficacy of these combination treatments, such as specific mutations in oncogenic proteins, may further improve the effectiveness of combination therapies, providing a better prognosis for melanoma patients.

SK119, a Novel Shikonin Derivative, Leads to Apoptosis in Melanoma Cell Lines and Exhibits Synergistic Effects with Vemurafenib and Cobimetinib

Melanoma is a complex and heterogenous disease, displays the deadliest form of skin cancer, and accounts for approx. 80% of all skin cancer deaths. In this study, we reported on the synthesis and pharmacological effects of a novel shikonin derivative (SK119), which is active in a nano-molar range and exhibits several promising in vitro effects in different human melanoma cells. SK119 was synthesized from shikonin as part of our search for novel, promising shikonin derivatives. It was screened against a panel of melanoma and non-tumorigenic cell lines using XTT viability assays. Moreover, we studied its pharmacological effects using apoptosis and Western blot experiments. Finally, it was combined with current clinically used melanoma therapeutics. SK119 exhibited IC₅₀ values in a nano-molar range, induced apoptosis and led to a dose-dependent increase in the expression and protein phosphorylation of HSP27 and HSP90 in WM9 and MUG-Mel 2 cells. Combinatorial treatment, which is highly recommended in melanoma, revealed the synergistic effects of SK119 with vemurafenib and cobimetinib. SK119 treatment changed the expression levels of apoptosis genes and death receptor expression and exhibited synergistic effects with vemurafenib and cobimetinib in human melanoma cells. Further research indicates a promising potential in melanoma therapy.

MALAT1 as master regulator of biomarkers predictive of pan-cancer multi-drug resistance in the context of recalcitrant NRAS signaling pathway identified using systems-oriented approach

NRAS, a protein mutated in several cancer types, is involved in key drug resistance mechanisms and is an intractable target. The development of drug resistance is one of the major impediments in targeted therapy. Currently, gene expression data is used as the most predictive molecular profile in pan-cancer drug sensitivity and resistance studies. However, the common regulatory mechanisms that drive drug sensitivity/resistance across cancer types are as yet, not fully understood. We focused on GDSC data on NRAS-mutant pan-cancer cell lines, to pinpoint key signaling targets in direct or indirect associations with NRAS, in order to identify other druggable targets involved in drug resistance. Large-scale gene expression, comparative gene co-expression and protein–protein interaction network analyses were performed on selected drugs inducing drug sensitivity/resistance. We validated our data from cell lines with those obtained from primary tissues from TCGA. From our big data studies validated with independent datasets, protein-coding hub genes FN1, CD44, TIMP1, SNAI2, and SPARC were found significantly enriched in signal transduction, proteolysis, cell adhesion and proteoglycans pathways in cancer as well as the PI3K/Akt-signaling pathway. Further studies of the regulation of these hub/driver genes by lncRNAs revealed several lncRNAs as prominent regulators, with MALAT1 as a possible master regulator. Transcription factor EGR1 may control the transcription rate of MALAT1 transcript. Synergizing these studies, we zeroed in on a pan-cancer regulatory axis comprising EGR1-MALAT1-driver coding genes playing a role. These identified gene regulators are bound to provide new paradigms in pan-cancer targeted therapy, a foundation for precision medicine, through the targeting of these key driver genes in the improvement of multi-drug sensitivity or resistance.

Establishment and characterization of an immortalized human giant congenital melanocytic nevi cell line

Treatments for giant congenital melanocytic nevi (GCMN) are extremely limited. Thus, there is an urgent need for development of relevant targeted therapies. However, current lack of preclinical cell models restricts progress in GCMN research. In this study, we aimed to establish and characterize an immortalized GCMN cell line. GCMN cells were successfully immortalized by means of lentivirus-mediated simian virus 40 large T transfection. The immortalized GNC cell line (ImGNC) showed lower proliferation rate and higher melanin content than primary melanocytes. Expression levels of the differentiation gene MITF and stemness genes TWIST1, SNAI1, and FOXD3 were elevated in ImGNCs; however, the established ImGNC cell line was immortalized but not transformed. Sanger sequencing detected the heterozygous NRAS^Q61K mutation in ImGNCs, but not the BRAF^V600E mutation. Despite carrying the NRAS^Q61K allele, ImGNCs demonstrated suppressed MAPK activation and elevated PI3K/Akt activation, as compared with primary melanocytes. Drug sensitivity analysis showed that ImGNCs are more sensitive to PI3K/Akt and Bcl-2 inhibitors than to MEK or ERK inhibitors. Unlike the proliferation-inhibiting effect of PI3K/Akt inhibitors, the Bcl-2 inhibitor navitoclax promptly promoted apoptosis in ImGNCs. Considering the low proliferation characteristics of GCMN in vivo, Bcl-2 may be a potential therapeutic target that warrants further research.

The frequency and clinicopathological significance of NRAS mutations in primary cutaneous nodular melanoma in Indonesia

BACKGROUND

Melanoma is a lethal skin malignancy with a high risk of metastasis, which prompts a need for research on treatment targets and prognostic factors. Recent studies show that the presence of neuroblastoma RAS viral oncogene homolog (NRAS) mutation can influence cell growth in melanomas. The NRAS mutation, which stimulates the mitogen-activated protein kinase (MAPK) signaling pathway, is associated with a lower survival rate. However, evidence from Indonesia population is still very rare. Further understanding of the role of NRAS mutations in Indonesian melanoma cases will be crucial in developing new management strategies for melanoma patients with NRAS mutations.

AIMS

To explore the frequency of NRAS mutations and their clinicopathological associations in patients with primary nodular cutaneous melanoma in Central Java and Yogyakarta, Indonesia.

METHODS AND RESULTS

Fifty-one paraffin-embedded tissue samples were collected from primary nodular skin melanoma cases between 2011 and 2019 from the two largest referral hospitals in Yogyakarta and Central Java, Indonesia. The NRAS mutation status was evaluated using qualitative real-time polymerase chain reaction (qRT-PCR). The association of NRAS mutation was analyzed with the following: age, gender, location, lymph node metastasis, ulceration, mitotic index, tumor-infiltrating lymphocytes (TILs), necrosis, tumor thickness, lymphovascular invasion (LVI), and tumor size. NRAS mutations were detected in 10 (19.6%) samples and predominantly observed (60%) in exon 2 (G12). These mutations were significantly correlated with lymph node metastases (p = .000); however, they were not associated with other variables analyzed in this study.

CONCLUSIONS

The prevalence of NRAS mutations in primary nodular cutaneous melanoma cases from Indonesia is consistent with previous studies and is significantly associated with increased lymph node metastases. However, the predominant mutation detected in exon 2 (G12) is different from previous studies conducted in other countries. This suggests that melanoma cases in Javanese people have different characteristics from other ethnicities.

High-throughput ex vivo drug testing identifies potential drugs and drug combinations for NRAS-positive malignant melanoma

Therapy options for patients with metastatic melanoma (MM) have considerably improved over the past decade. However, many patients still need effective therapy after unsuccessful immunotherapy, especially patients with BRAF-negative tumors who lack the option of targeted treatment second line. Therefore, the elucidation of efficient and personalized therapy options for these patients is required. In this study, three patient-derived cancer cells (PDCs) were established from NRAS Q61-positive MM patients. The response of PDCs and five established melanoma cell lines (two NRAS-positive, one wild type, and two BRAF V600-positive) was evaluated toward a panel of 527 oncology drugs using high-throughput drug sensitivity and resistance testing. The PDCs and cell lines displayed strong responses to MAPK inhibitors, as expected. Additionally, the PDCs and cell lines were responsive to PI3K/mTOR, mTOR, and PLK1 inhibitors among other effective drugs currently undergoing clinical trials. Combinations with a MEK inhibitor were tested with other targeted agents to identify effective synergies. MEK inhibitor showed synergy with multikinase inhibitor ponatinib, ABL inhibitor nilotinib, PI3K/mTOR inhibitor pictilisib, and pan-RAF inhibitor LY3009120. The application of the patients' cancer cells for functional drug testing ex vivo is one step further in the process of identifying potential agents and agent combinations to personalize treatment for patients with MM. Our preliminary study results suggest that this approach has the potential for larger-scale drug testing and personalized treatment applications in our expansion trial. Our results show that drug sensitivity and resistance testing may be implementable in the treatment planning of patients with MM.

HSP70 inhibition blocks adaptive resistance and synergizes with MEK inhibition for the treatment of NRAS-mutant melanoma

NRAS-mutant melanoma is currently a challenge to treat. This is due to an absence of inhibitors directed against mutant NRAS, along with adaptive and acquired resistance of this tumor type to inhibitors in the MAPK pathway. Inhibitors to MEK (mitogen-activated protein kinase kinase) have shown some promise for NRAS-mutant melanoma. In this work we explored the use of MEK inhibitors for NRAS-mutant melanoma. At the same time we investigated the impact of the brain microenvironment, specifically astrocytes, on the response of a melanoma brain metastatic cell line to MEK inhibition. These parallel avenues led to the surprising finding that astrocytes enhance the sensitivity of melanoma tumors to MEK inhibitors (MEKi). We show that MEKi cause an upregulation of the transcription factor ID3, which confers resistance. This upregulation of ID3 is blocked by conditioned media from astrocytes. We show that silencing ID3 enhances the sensitivity of melanoma to MEK inhibitors, thus mimicking the effect of the brain microenvironment. Moreover, we report that ID3 is a client protein of the chaperone HSP70, and that HSP70 inhibition causes ID3 to misfold and accumulate in a detergent-insoluble fraction in cells. We show that HSP70 inhibitors synergize with MEK inhibitors against NRAS-mutant melanoma, and that this combination significantly enhances the survival of mice in two different models of NRAS-mutant melanoma. These studies highlight ID3 as a mediator of adaptive resistance, and support the combined use of MEK and HSP70 inhibitors for the therapy of NRAS-mutant melanoma.

SIGNIFICANCE

MEK inhibitors are currently used for NRAS-mutant melanoma, but have shown modest efficacy as single agents. This research shows a synergistic effect of combining HSP70 inhibitors with MEK inhibitors for the treatment of NRAS mutant melanoma.

Epidemiology of brain metastases and leptomeningeal disease

Brain metastases affect a significant percentage of patients with advanced extracranial malignancies. Yet, the incidence of brain metastases remains poorly described, largely due to limitations of population-based registries, a lack of mandated reporting of brain metastases to federal agencies, and historical difficulties with delineation of metastatic involvement of individual organs using claims data. However, in 2016, the Surveillance Epidemiology and End Results (SEER) program released data relating to the presence vs absence of brain metastases at diagnosis of oncologic disease. In 2020, studies demonstrating the viability of utilizing claims data for identifying the presence of brain metastases, date of diagnosis of intracranial involvement, and initial treatment approach for brain metastases were published, facilitating epidemiologic investigations of brain metastases on a population-based level. Accordingly, in this review, we discuss the incidence, clinical presentation, prognosis, and management patterns of patients with brain metastases. Leptomeningeal disease is also discussed. Considerations regarding individual tumor types that commonly metastasize to the brain are provided.

Adjuvant Therapy for Cutaneous Melanoma

This article presents the current data supporting adjuvant therapy for patients with cutaneous melanoma. With the recent development of novel immunotherapy agents as well as targeted therapy, there are strong data to support the use of these therapies in patients at high risk of developing recurrent or metastatic disease.

Unraveling the Wide Spectrum of Melanoma Biomarkers

The use of biomarkers in medicine has become essential in clinical practice in order to help with diagnosis, prognostication and prediction of treatment response. Since Alexander Breslow’s original report on “melanoma and prognostic values of thickness”, providing the first biomarker for melanoma, many promising new biomarkers have followed. These include serum markers, such as lactate dehydrogenase and S100 calcium-binding protein B. However, as our understanding of the DNA mutational profile progresses, new gene targets and proteins have been identified. These include point mutations, such as mutations of the BRAF gene and tumour suppressor gene tP53. At present, only a small number of the available biomarkers are being utilised, but this may soon change as more studies are published. The aim of this article is to provide a comprehensive review of melanoma biomarkers and their utility for current and, potentially, future clinical practice.

Melanoma genomics: a state-of-the-art review of practical clinical applications

Our collective understanding of melanoma genomics has rapidly expanded in the past decade, bringing great promise to patients affected with the most severe and aggressive cases of melanoma. In this review, we present the practical clinical impact of genetics and genomics on modern melanoma diagnosis and treatment. Characterization of somatic driver mutations, which can be used to distinguish different subtypes of melanoma such as nonacral cutaneous melanoma (NACM), desmoplastic melanoma (DM), acral melanoma (AM), mucosal melanoma (MM) and uveal melanoma (UM), has led to the development of many targeted therapies against these tumours. Although targeted therapies exist for certain mutations, such as BRAF and KIT, other genotypes respond to newer-generation immune therapies such as immune checkpoint inhibitors. Epigenetics also plays a critical role in melanoma pathogenesis and drug resistance, holding promise for new treatment avenues. In this review, special attention is placed on clinical trials and translational research, especially novel genomic tests aimed to benefit patients on an individualized level in the current emerging era of personalized therapy.

Case Report: Rechallenge With BRAF and MEK Inhibitors in Metastatic Melanoma: A Further Therapeutic Option in Salvage Setting?

BACKGROUND

The combination of BRAF and MEK inhibitors represents the standard of care treatment for patients with metastatic BRAF-mutated melanoma, notwithstanding the high frequency of emergent resistance. Moreover, therapeutic options outside clinical trials are scarce when patients have progressed after both targeted therapy and therapy with immune checkpoint inhibitors. In this article, we report our experience with targeted therapy rechallenging with BRAF and MEK inhibitors in patients with metastatic BRAF-mutated melanoma after progression with kinase inhibitors and immunotherapy.

METHODS

Four patients with metastatic BRAF-mutated melanoma were rechallenged with BRAF and MEK inhibitors after progression with targeted therapy and subsequent immunotherapy (checkpoint inhibitors).

RESULTS

Two patients (one of them was heavily pretreated) had partial response over 36 months (with local treatment on oligoprogression disease) and 10 months, respectively. A third patient with multisite visceral disease and high serum levels of lactate dehydrogenase had a short-lived clinical benefit rapidly followed by massive progression of disease (early progressor). The fourth patient, currently on treatment with BRAF/MEK inhibitors, is showing a clinical benefit and radiological stable disease over 3 months of therapy. Adverse events were manageable, similar to those reported during the first targeted therapy; the treatment was better tolerated at rechallenge compared with the first treatment by two out of four patients.

Inhibition of the Myocardin-Related Transcription Factor Pathway Increases Efficacy of Trametinib in NRAS-Mutant Melanoma Cell Lines

Simple Summary

Malignant melanoma is the most aggressive skin cancer, and treatment is often ineffective due to the development of resistance to targeted therapeutic agents. The most prevalent form of melanoma with a mutated BRAF gene has an effective treatment, but the second most common mutation in melanoma (NRAS) leads to tumors that lack targeted therapies. In this study, we show that NRAS mutant human melanoma cells that are most resistant to inhibition of the oncogenic pathway have a second activated pathway (Rho). Inhibiting that pathway at one of several points can produce more effective cell killing than inhibition of the NRAS pathway alone. This raises the possibility that such a combination treatment could prove effective in those melanomas that fail to respond to existing targeted therapies such as vemurafenib and trametinib.

Abstract

The Ras/MEK/ERK pathway has been the primary focus of targeted therapies in melanoma; it is aberrantly activated in almost 80% of human cutaneous melanomas (≈50% BRAFV600 mutations and ≈30% NRAS mutations). While drugs targeting the MAPK pathway have yielded success in BRAFV600 mutant melanoma patients, such therapies have been ineffective in patients with NRAS mutant melanomas in part due to their cytostatic effects and primary resistance. Here, we demonstrate that increased Rho/MRTF-pathway activation correlates with high intrinsic resistance to the MEK inhibitor, trametinib, in a panel of NRAS mutant melanoma cell lines. A combination of trametinib with the Rho/MRTF-pathway inhibitor, CCG-222740, synergistically reduced cell viability in NRAS mutant melanoma cell lines in vitro. Furthermore, the combination of CCG-222740 with trametinib induced apoptosis and reduced clonogenicity in SK-Mel-147 cells, which are highly resistant to trametinib. These findings suggest a role of the Rho/MRTF-pathway in intrinsic trametinib resistance in a subset of NRAS mutant melanoma cell lines and highlight the therapeutic potential of concurrently targeting the Rho/MRTF-pathway and MEK in NRAS mutant melanomas.

Prebiotic-Induced Anti-tumor Immunity Attenuates Tumor Growth

Growing evidence supports the importance of gut microbiota in the control of tumor growth and response to therapy. Here, we select prebiotics that can enrich bacterial taxa that promote anti-tumor immunity. Addition of the prebiotics inulin or mucin to the diet of C57BL/6 mice induces anti-tumor immune responses and inhibition of BRAF mutant melanoma growth in a subcutaneously implanted syngeneic mouse model. Mucin fails to inhibit tumor growth in germ-free mice, indicating that the gut microbiota is required for the activation of the anti-tumor immune response. Inulin and mucin drive distinct changes in the microbiota, as inulin, but not mucin, limits tumor growth in syngeneic mouse models of colon cancer and NRAS mutant melanoma and enhances the efficacy of a MEK inhibitor against melanoma while delaying the emergence of drug resistance. We highlight the importance of gut microbiota in anti-tumor immunity and the potential therapeutic role for prebiotics in this process.

Antibody-drug conjugates: an evolving approach for melanoma treatment

Melanoma continues to be an aggressive and deadly form of skin cancer while therapeutic options are continuously developing in an effort to provide long-term solutions for patients. Immunotherapeutic strategies incorporating antibody-drug conjugates (ADCs) have seen varied levels of success across tumor types and represent a promising approach for melanoma. This review will explore the successes of FDA-approved ADCs to date compared to the ongoing efforts of melanoma-targeting ADCs. The challenges and opportunities for future therapeutic development are also examined to distinguish how ADCs may better impact individuals with malignancies such as melanoma.

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.

The Association of Residential Altitude on the Molecular Profile and Survival of Melanoma: Results of an Interreg Study

Cutaneous melanoma (CM) incidence is rising worldwide and is the primary cause of death from skin disease in the Western world. Personal risk factors linked to environmental ultraviolet radiation (UVR) are well-known etiological factors contributing to its development. Nevertheless, UVR can contribute to the development of CM in different patterns and to varying degrees. The present study aimed at investigating whether altitude of residence can contribute to the development of specific types of CM and/or influence its progression. To this aim, 306 formalin-fixed and paraffin-embedded (FFPE) tissues from primary CM diagnosed in different geographical areas were submitted to B-RAF proto-oncogene serine/threonine kinase (BRAF) and N-RAS proto-oncogene GTPase (NRAS) mutational status detection and mRNA and miRNA profiling by qPCR. Genes were chosen for their functions in specific processes, such as immune response (CD2, PDL1, or CD274) and pigmentation (MITF, TYRP1, and TRPM1). Furthermore, four microRNAs, namely miR-150-5p, miR-155-5p, miR-204-5p, and miR-211-5p, were included in the profiling. Our results highlight differences in the gene expression profile of primary CM with respect to the geographical area and the altitude of residence. Melanoma-specific survival was influenced by the gene expression of mRNA and miRNAs and varied with the altitude of patients' residence. In detail, TYRP1 and miR-204-5p were highly expressed in patients living at higher altitudes, unlike miR-150-5p, miR-155-5p, and miR-211-5p. Since miRNAs are highly regulated by reactive oxygen species, it is possible that different regulatory mechanisms characterize CMs at different altitudes due to the different environment and UVR intensity.

MDM2 antagonists overcome intrinsic resistance to CDK4/6 inhibition by inducing p21

Intrinsic resistance of unknown mechanism impedes the clinical utility of inhibitors of cyclin-dependent kinases 4 and 6 (CDK4/6i) in malignancies other than breast cancer. Here, we used melanoma patient-derived xenografts (PDXs) to study the mechanisms for CDK4/6i resistance in preclinical settings. We observed that melanoma PDXs resistant to CDK4/6i frequently displayed activation of the phosphatidylinositol 3-kinase (PI3K)-AKT pathway, and inhibition of this pathway improved CDK4/6i response in a p21-dependent manner. We showed that a target of p21, CDK2, was necessary for proliferation in CDK4/6i-treated cells. Upon treatment with CDK4/6i, melanoma cells up-regulated cyclin D1, which sequestered p21 and another CDK inhibitor, p27, leaving a shortage of p21 and p27 available to bind and inhibit CDK2. Therefore, we tested whether induction of p21 in resistant melanoma cells would render them responsive to CDK4/6i. Because p21 is transcriptionally driven by p53, we coadministered CDK4/6i with a murine double minute (MDM2) antagonist to stabilize p53, allowing p21 accumulation. This resulted in improved antitumor activity in PDXs and in murine melanoma. Furthermore, coadministration of CDK4/6 and MDM2 antagonists with standard of care therapy caused tumor regression. Notably, the molecular features associated with response to CDK4/6 and MDM2 inhibitors in PDXs were recapitulated by an ex vivo organotypic slice culture assay, which could potentially be adopted in the clinic for patient stratification. Our findings provide a rationale for cotargeting CDK4/6 and MDM2 in melanoma.

Mutations in the BRAF, NRAS, and C-KIT Genes of Patients Diagnosed with Melanoma in Colombia Population

INTRODUCTION

Mutations in the BRAF, NRAS, and C-KIT genes have been associated with the histopathological characteristics of melanoma. Likewise, the incidence of each of these subtypes changes according to the geographical origin of the population analyzed.

OBJECTIVE

To determine the mutation frequency in exons 11 and 15 of the BRAF gene, exons 1 and 2 of the NRAS gene, and exons 11, 13, and 17 of the C-KIT gene and to relate it with histological subtypes in patients from a region with high levels of ultraviolet radiation. Methodology. The clinicopathological characteristics of 54 cutaneous melanoma samples were analyzed. Mutation analysis was performed via qPCR on paraffin-embedded tumor tissue samples using probes specific for the V600E mutation. Amplification of exons 11 and 15 of the BRAF gene, exons 1 and 2 of the NRAS gene, and exons 11, 13, and 17 of the C-KIT gene was performed for subsequent sequencing using the Sanger method.

RESULT

The most frequent histological subtype in the analyzed sample was lentigo maligna/lentigo maligna melanoma (52%) followed by acral lentiginous melanoma (20%). The BRAF-V600 variant was the most frequent (63.6%). The most frequent (54%) mutation in NRAS was p.Lys5∗. In the C-KIT gene, only the Val560Ala mutation was found.

CONCLUSION

Differences in histological subtypes and mutations in the BRAF, NRAS, and C-KIT genes were found in the analyzed population. This indicates that environmental and genetic factors significantly influence the introduction of the disease in this geographic region.

Primary tumor characteristics and next-generation sequencing mutations as biomarkers for melanoma immunotherapy response

INTRODUCTION

Considerable advances in melanoma have been realized through immunotherapy. The principal aim was to determine whether primary tumor characteristics or next-generation sequencing (NGS) could serve as markers of immunotherapy response.

METHODS AND RESULTS

The study cohort consisted of 67 patients who received immunotherapy for recurrent or metastatic melanoma and for whom primary tumor biopsies and pathology reports were available. A subset of 59 patient tumors were profiled using an NGS panel of 50 cancer-related genes. Objective response rate to immunotherapy was assessed using RECIST v1.1 criteria. Progression-free survival (PFS) and overall survival (OS) were used as endpoints. Lymphovascular invasion (LVI) strongly correlated with an increased proportion of immunotherapy responders (p = .002). PFS interval (p = .003) and OS (p = .036) were significantly higher in patients with LVI. NRAS mutation was more strongly correlated with an increased proportion of immunotherapy responders (p =.050). PFS was significantly higher in patients with NRAS mutation (p = .042); no difference in OS (p = .111).

DISCUSSION

This analysis demonstrates an association between lymphovascular invasion and immunotherapy response. Additionally, NGS mutation analysis demonstrated a potential association between NRAS mutations and immunotherapy response.

The EMT Transcription Factor ZEB2 Promotes Proliferation of Primary and Metastatic Melanoma While Suppressing an Invasive, Mesenchymal-Like Phenotype

Epithelial-to-mesenchymal transition (EMT)-inducing transcription factors (TF) are well known for their ability to induce mesenchymal states associated with increased migratory and invasive properties. Unexpectedly, nuclear expression of the EMT-TF ZEB2 in human primary melanoma has been shown to correlate with reduced invasion. We report here that ZEB2 is required for outgrowth for primary melanomas and metastases at secondary sites. Ablation of Zeb2 hampered outgrowth of primary melanomas in vivo, whereas ectopic expression enhanced proliferation and growth at both primary and secondary sites. Gain of Zeb2 expression in pulmonary-residing melanoma cells promoted the development of macroscopic lesions. In vivo fate mapping made clear that melanoma cells undergo a conversion in state where ZEB2 expression is replaced by ZEB1 expression associated with gain of an invasive phenotype. These findings suggest that reversible switching of the ZEB2/ZEB1 ratio enhances melanoma metastatic dissemination. SIGNIFICANCE: ZEB2 function exerts opposing behaviors in melanoma by promoting proliferation and expansion and conversely inhibiting invasiveness, which could be of future clinical relevance. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/14/2983/F1.large.jpg.

In vivo antitumoral effect of 4-nerolidylcatechol (4-NC) in NRAS-mutant human melanoma

NRAS-mutations arise in 15-20% of all melanomas and are associated with aggressive disease and poor prognosis. Besides, the treatment for NRAS-mutant melanoma are not very efficient and is currently limited to immune checkpoints inhibitors or aggressive chemotherapy. 4-nerolidylcathecol (4-NC), a natural product extracted from Pothomorphe umbellata, induces apoptosis in melanoma cells by ROS production, DNA damage and increased p53 expression, in addition to inhibiting invasion in reconstructed skin. Moreover, 4-NC showed cytotoxicity in BRAF/MEKi-resistant and naive melanoma cells by Endoplasmic Reticulum (ER) stress induction in vitro. We evaluated the in vivo efficacy and the systemic toxicity of 4-NC in a NRAS-mutant melanoma model. 4-NC was able to significantly suppress tumor growth 4-fold compared to controls. Cleaved PARP and p53 expression were increased indicating cell death. As a proof of concept, MMP-2 and MMP-14 gene expression were decreased, demonstrating a possible role of 4-NC in melanoma invasion inhibition. Toxicological analysis indicated minor changes in the liver and bone marrow, but this toxicity was very mild when compared to other proteasome inhibitors and ER stress inductors already described. Our data indicate that 4-NC can counteract melanoma growth in vivo with minor adverse effects, suggesting further investigation as a potential NRAS-mutant melanoma treatment.

Applications of personalised signalling network models in precision oncology

As our ability to provide in-depth, patient-specific characterisation of the molecular alterations within tumours rapidly improves, it is becoming apparent that new approaches will be required to leverage the power of this data and derive the full benefit for each individual patient. Systems biology approaches are beginning to emerge within this field as a potential method of incorporating large volumes of network level data and distilling a coherent, clinically-relevant prediction of drug response. However, the initial promise of this developing field is yet to be realised. Here we argue that in order to develop these precise models of individual drug response and tailor treatment accordingly, we will need to develop mathematical models capable of capturing both the dynamic nature of drug-response signalling networks and key patient-specific information such as mutation status or expression profiles. We also review the modelling approaches commonly utilised within this field, and outline recent examples of their use in furthering the application of systems biology for a precision medicine approach to cancer treatment.

A Phase I Study of LY3009120, a Pan-RAF Inhibitor, in Patients with Advanced or Metastatic Cancer

Mutations in ERK signaling drive a significant percentage of malignancies. LY3009120, a pan-RAF and dimer inhibitor, has preclinical activity in RAS- and BRAF-mutated cell lines including BRAF-mutant melanoma resistant to BRAF inhibitors. This multicenter, open-label, phase I clinical trial (NCT02014116) consisted of part A (dose escalation) and part B (dose confirmation) in patients with advanced/metastatic cancer. In part A, oral LY3009120 was dose escalated from 50 to 700 mg twice a day on a 28-day cycle. In part B, 300 mg LY3009120 was given twice a day. The primary objective was to identify a recommended phase II dose (RP2D). Secondary objectives were to evaluate safety, pharmacokinetics, and preliminary efficacy. Identification of pharmacodynamic biomarkers was exploratory. In parts A and B, 35 and 16 patients were treated, respectively (N = 51). In part A, 6 patients experienced eight dose-limiting toxicities. The RP2D was 300 mg twice a day. Common (>10%) any-grade drug-related treatment-emergent adverse events were fatigue (n = 15), nausea (n = 12), dermatitis acneiform (n = 10), decreased appetite (n = 7), and maculopapular rash (n = 7). The median duration of treatment was 4 weeks; 84% of patients completed one or two cycles of treatment. Exposures observed at 300 mg twice a day were above the preclinical concentration associated with tumor regression. Eight patients had a best overall response of stable disease; there were no complete or partial clinical responses. Despite adequate plasma exposure levels, predicted pharmacodynamic effects were not observed.

FOXO3a‑SIRT6 axis suppresses aerobic glycolysis in melanoma

Melanoma, the most aggressive human skin tumor, has a very short survival time, and there are currently no effective treatments. Alterations in cell metabolism, such as enhanced aerobic glycolysis, have been identified as hallmarks of cancer cells. In the present study, bioinformatics studies using online databases revealed that FOXO3a expression was lower in melanoma tissues compared with normal tissues and nevus. Additionally, Kaplan‑Meier analysis showed that high expression of FOXO3a predicted an improved prognosis for patients with melanoma. Furthermore, Pearson correlation analysis indicated that the expression of FOXO3a was positively correlated with SIRT6 expression and negatively correlated with the expression levels of a number of glycolysis‑associated genes. Chromatin immunoprecipitation and luciferase assays showed that FOXO3a was enriched in the SIRT6 promoter region and promoted its transcription. Then, SIRT6 was overexpressed in FOXO3a‑knockdown MV3 cells and downregulated in FOXO3a‑overexpressing MV3 cells by using lentivirus‑mediated stable infection. The results showed that SIRT6 knockdown or overexpression rescued the effects of FOXO3a overexpression or knockdown, respectively, on glycolysis, as determined by glucose uptake, glucose consumption and lactate production assays, the expression of glycolytic genes and glucose stress flux tests. SIRT6 overexpression also suppressed FOXO3a knockdown‑induced tumor growth in a mouse model. The present findings indicated that the FOXO3a‑SIRT6 regulatory axis inhibited glucose metabolism and tumor cell proliferation in melanoma, and provided novel insight into potential therapeutic strategies to treat this disease.

Epigenetic polypharmacology: A new frontier for epi-drug discovery

Recently, despite the great success achieved by the so-called "magic bullets" in the treatment of different diseases through a marked and specific interaction with the target of interest, the pharmacological research is moving toward the development of "molecular network active compounds," embracing the related polypharmacology approach. This strategy was born to overcome the main limitations of the single target therapy leading to a superior therapeutic effect, a decrease of adverse reactions, and a reduction of potential mechanism(s) of drug resistance caused by robustness and redundancy of biological pathways. It has become clear that multifactorial diseases such as cancer, neurological, and inflammatory disorders, may require more complex therapeutic approaches hitting a certain biological system as a whole. Concerning epigenetics, the goal of the multi-epi-target approach consists in the development of small molecules able to simultaneously and (often) reversibly bind different specific epi-targets. To date, two dual histone deacetylase/kinase inhibitors (CUDC-101 and CUDC-907) are in an advanced stage of clinical trials. In the last years, the growing interest in polypharmacology encouraged the publication of high-quality reviews on combination therapy and hybrid molecules. Hence, to update the state-of-the-art of these therapeutic approaches avoiding redundancy, herein we focused only on multiple medication therapies and multitargeting compounds exploiting epigenetic plus nonepigenetic drugs reported in the literature in 2018. In addition, all the multi-epi-target inhibitors known in literature so far, hitting two or more epigenetic targets, have been included.

A genome-wide CRISPR screen identifies FBXO42 involvement in resistance toward MEK inhibition in NRAS-mutant melanoma

NRAS mutations are the most common alterations among RAS isoforms in cutaneous melanoma, with patients harboring these aggressive tumors having a poor prognosis and low survival rate. The main line of treatment for these patients is MAPK pathway‐targeted therapies, such as MEK inhibitors, but, unfortunately, the response to these inhibitors is variable due to tumor resistance. Identifying genetic modifiers involved in resistance toward MEK‐targeted therapy may assist in the development of new therapeutic strategies, enhancing treatment response and patient survival. Our whole‐genome CRISPR‐Cas9 knockout screen identified the target Kelch domain‐containing F‐Box protein 42 (FBXO42) as a factor involved in NRAS‐mutant melanoma‐acquired resistance to the MEK1/2 inhibitor trametinib. We further show that FBXO42, an E3 ubiquitin ligase, is involved in the TAK1 signaling pathway, possibly prompting an increase in active P38. In addition, we demonstrate that combining trametinib with the TAK1 inhibitor, takinib, is a far more efficient treatment than trametinib alone in NRAS‐mutant melanoma cells. Our findings thus show a new pathway involved in NRAS‐mutant melanoma resistance and provide new opportunities for novel therapeutic options.

Neuroblastoma rat sarcoma mutated melanoma: That's what we got so far

Neuroblastoma rat sarcoma (NRAS) mutation, occurring in about 20%-30% of cutaneous melanomas, leads to activation of RAS-RAF-MAPK cascade and represents a clear distinct clinicopathological entity in melanoma. In contrast with BRAF mutant melanoma, no specific target therapies are available outside the setting of clinical trials. In the field of immunoncology, the predictive role of NRAS mutation with respect to checkpoint inhibitors treatment has not clearly established and deserves further investigation. At present, the standard treatment is the same as for BRAF wild type melanoma. Ongoing trials are exploring novel combination strategies among patients with advanced NRAS mutant melanoma.

Melanoma vaccines: clinical status and immune endpoints

It has been known for decades that the immune system can be spontaneously activated against melanoma. The presence of tumor infiltrating lymphocytes in tumor deposits is a positive prognostic factor. Cancer vaccination includes approaches to generate, amplify, or skew antitumor immunity. To accomplish this goal, tested approaches involve administration of tumor antigens, antigen presenting cells or other immune modulators, or direct modulation of the tumor. Because the success of checkpoint blockade can depend in part on an existing antitumor response, cancer vaccination may play an important role in future combination therapies. In this review, we discuss a variety of melanoma vaccine approaches and methods to determine the biological impact of vaccination.

New primary melanoma in a patient under triple therapy with vemurafenib, cobimetinib, and atezolizumab for metastatic melanoma

New primary melanomas (NPMs) in the era of combination treatments for melanoma constitute a challenge for physicians, especially due to the increased incidence of NPMs in patients treated with BRAF inhibitors. We present the unique case of a patient that developed an invasive NPM while under treatment with a combination of vemurafenib, cobimetinib, and atezolizumab. A 39-year-old white male was treated with vemurafenib, cobimetinib, and atezolizumab for a stage IV (T0, N3, M1) BRAF-V600E mutated malignant melanoma in the context of a clinical trial. Eight months from treatment initiation he was diagnosed with an NPM on his back that was found to be BRAF-wild type and neuroblastoma ras mutated, while he was in complete remission. Wide excision of the lesion followed, and the patient was not withdrawn from study treatment. Twenty-two months from treatment initiation, he is still in complete remission. NPMs are a well-known adverse effect of BRAF inhibitors and pose a challenge for the treating physician since these lesions are BRAF-wild type and usually have aggressive biologic behaviour. Invasive NPMs require an aggressive management strategy with clear guidelines to prevent the emergence of advanced or metastatic disease. The emergence of invasive NPMs in patients treated with triple regimens with BRAF/mitogen-activated protein kinase kinase inhibitors and PD1/PDL1 inhibitors is at least unexpected and constitutes a therapeutic stalemate for the physician. Through this case report, we aim to increase awareness about the diagnosis and management of patients with NPM and to express our concerns regarding further management of NPMs in patients under triple combination treatment.

Neural crest state activation in NRAS driven melanoma, but not in NRAS-driven melanocyte expansion

NRAS mutations are frequently found in many deadly malignancies and are the second most common oncogene driving malignant melanoma. Here, we generate a rapid transient transgenic zebrafish model of NRASQ61R-mutant melanoma. These fish develop extensive melanocytic proliferation in approximately 4 weeks. The majority of these lesions do not engraft upon transplantation and lack overt histologic features of malignancy. Our previous work demonstrated that activation of a neural crest cell transcriptional program is a key initiating event in zebrafish BRAF/p53-driven melanomas using the fluorescent reporter crestin:EGFP. By 8-12 weeks of age, some lesions progress to malignant melanoma and have cytologic atypia, destructive tissue invasion, and express neural crest progenitor markers, including crestin:EGFP. Our studies demonstrate that NRASQ61R induces extensive melanocyte expansion, which arise during zebrafish development and lack a transformed phenotype. These early lesions are highly predisposed to reactivate a neural crest progenitor fate and form malignant melanomas.

5-Arylidene(chromenyl-methylene)-thiazolidinediones: Potential New Agents against Mutant Oncoproteins K-Ras, N-Ras and B-Raf in Colorectal Cancer and Melanoma

Background and objectives: Cancer represents the miscommunication between and within the body cells. The mutations of the oncogenes encoding the MAPK pathways play an important role in the development of tumoral diseases. The mutations of KRAS and BRAF oncogenes are involved in colorectal cancer and melanoma, while the NRAS mutations are associated with melanoma. Thiazolidine-2,4-dione is a versatile scaffold in medicinal chemistry and a useful tool in the development of new antitumoral compounds. The aim of our study was to predict the pharmacokinetic/pharmacodynamic properties, the drug-likeness and lead-likeness of two series of synthetic 5-arylidene(chromenyl-methylene)-thiazolidinediones, the molecular docking on the oncoproteins K-Ras, N-Ras and B-Raf, and to investigate the cytotoxicity of the compounds, in order to select the best structural profile for potential anticancer agents. Materials and Methods: In our paper we studied the cytotoxicity of two series of thiazolidine-2,4-dione derivatives, their ADME-Tox properties and the molecular docking on a mutant protein of K-Ras, two isoforms of N-Ras and an isoform of B-Raf with 16 mutations. Results: The heterocyclic compounds strongly interact with K-Ras and N-Ras right after their posttranslational processing and/or compete with GDP for the nucleotide-binding site of the two GTPases. They are less active against the GDP-bound states of the two targets. All derivatives have a similar binding pattern in the active site of B-Raf. Conclusions: The data obtained encourage the further investigation of the 5-arylidene(chromenyl-methylene)-thiazolidinediones as potential new agents against the oncoproteins K-Ras, N-Ras and B-Raf.