Prognostic significance of BRAF and NRAS mutations in melanoma: a German study from routine care

Design, synthesis, and evaluation of novel quindoline derivatives with fork-shaped side chains as RNA G-quadruplex stabilizers for repressing oncogene NRAS translation

NRAS mutation is the second most common oncogenic factor in cutaneous melanoma. Inhibiting NRAS translation by stabilizing the G-quadruplex (G4) structure with small molecules seems to be a potential strategy for cancer therapy due to the NRAS protein's lack of a druggable pocket. To enhance the effects of previously reported G4 stabilizers quindoline derivatives, we designed and synthesized a novel series of quindoline derivatives with fork-shaped side chains by introducing (alkylamino)alkoxy side chains. Panels of experimental results showed that introducing a fork-shaped (alkylamino)alkoxy side chain could enhance the stabilizing abilities of the ligands against NRAS RNA G-quadruplexes and their anti-melanoma activities. One of them, 10b, exhibited good antitumor activity in the NRAS-mutant melanoma xenograft mouse model, showing the therapeutic potential of this kind of compounds.

A phase II study of efficacy and safety of the MEK inhibitor tunlametinib in patients with advanced NRAS-mutant melanoma

BACKGROUND

NRAS-mutant melanoma is an aggressive subtype with poor prognosis; however, there is no approved targeted therapy to date worldwide.

METHODS

We conducted a multicenter, single-arm, phase II, pivotal registrational study that evaluated the efficacy and safety of the MEK inhibitor tunlametinib in patients with unresectable, stage III/IV, NRAS-mutant melanoma (NCT05217303). The primary endpoint was objective response rate (ORR) assessed by independent radiological review committee (IRRC) per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1. The secondary endpoints included progression-free survival (PFS), disease control rate (DCR), duration of response(DOR), overall survival (OS) and safety.

FINDINGS

Between November 2, 2020 and February 11, 2022, a total of 100 patients were enrolled. All (n = 100) patients received at least one dose of tunlametinib (safety analysis set [SAS]) and 95 had central laboratory-confirmed NRAS mutations (full analysis set [FAS]). In the FAS, NRAS mutations were observed at Q61 (78.9%), G12 (15.8%) and G13 (5.3%). The IRRC-assessed ORR was 35.8%, with a median DOR of 6.1 months. The median PFS was 4.2 months, DCR was 72.6% and median OS was 13.7 months. Subgroup analysis showed that in patients who had previously received immunotherapy, the ORR was 40.6%. No treatment-related deaths occurred.

INTERPRETATION

Tunlametinib showed promising antitumor activity with a manageable safety profile in patients with advanced NRAS-mutant melanoma, including those who had prior exposure to immunotherapy. The findings warrant further validation in a randomized clinical trial.

Immunotherapy in the Management of Sinonasal Mucosal Melanoma: A Systematic Review

OBJECTIVE

The aim of this work is to comprehensively review and synthesize the literature related to sinonasal mucosal melanoma (SNMM) treatment with immunotherapy, including potentially targetable genetic mutations, survival outcomes, and adverse events.

DATA SOURCES

Embase, Cochrane, Scopus, and Web of Science.

REVIEW METHODS

The study protocol was designed according to Preferred Reporting Items for Systematic Reviews and Meta-analysis statement. Databases were searched from inception through May 23, 2023.

RESULTS

A total of 42 studies met inclusion criteria. Twenty-four of the included studies reported genetic mutations for a combined 787 patients with SNMM. 8.1% (95% confidence interval, CI: 7.6-8.6), 18.9% (95% CI: 18.1-19.8), and 8.5% (95% CI: 8.1-9.0) of reported patients were positive for BRAF, NRAS, and KIT mutations, respectively. The presence of brisk tumor-infiltrating lymphocytes was associated with improved recurrence-free survival and overall survival (OS). Six studies reported a combined 5-year OS after adjuvant immunotherapy treatment of 42.6% (95% CI: 39.4-45.8). Thirteen studies encompassing 117 patients reported adjuvant or salvage immune checkpoint inhibitor (ICI) immunotherapy response rates: 40.2% (95% CI: 36.8-43.6) had a positive response (tumor volume reduction or resolution). Eleven studies reported direct comparisons between SNMM patients treated with or without immunotherapy; the majority (7/11) reported survival benefit for their entire cohort or select subgroups of SNMM patients. With the transition to modern ICIs, there is a stronger trend toward survival improvement with adjuvant ICI. Tumors with Ki67 <40% may respond better to ICI's.

CONCLUSION

ICI therapy can be an effective in select SNMM patients, especially those with advanced/metastatic disease.

Targeted DNA Sequencing of Cutaneous Melanoma Identifies Prognostic and Predictive Alterations

BACKGROUND

Cutaneous melanoma (CM) can be molecularly classified into four groups: BRAF mutant, NRAS mutant, NF1 mutant and triple wild-type (TWT) tumors lacking any of these three alterations. In the era of immune checkpoint inhibition (ICI) and targeted molecular therapy, the clinical significance of these groups remains unclear. Here, we integrate targeted DNA sequencing with comprehensive clinical follow-up in CM patients.

METHODS

This was a retrospective cohort study that assessed clinical and molecular features from patients with localized or metastatic CM who underwent targeted next-generation sequencing as part of routine clinical care. A total of 254 patients with CM who had a CLIA-certified targeted sequencing assay performed on their tumor tissue were included.

RESULTS

Of the 254 patients with cutaneous melanoma, 77 were BRAF mutant (30.3%), 77 were NRAS mutant (30.3%), 47 were NF1 mutant (18.5%), 33 were TWT (13.0%) and the remaining 20 (7.9%) carried mutations in multiple driver genes (BRAF/NRAS/NF1 co-mutated). The majority of this co-mutation group carried mutations in NF1 (n = 19 or 90%) with co-occurring mutations in BRAF or NRAS, often with a weaker oncogenic variant. Consistently, NF1 mutant tumors harbored numerous significantly co-altered genes compared to BRAF or NRAS mutant tumors. The majority of TWT tumors (n = 29, 87.9%) harbor a pathogenic mutation within a known Ras/MAPK signaling pathway component. Of the 154 cases with available TMB data, the median TMB was 20 (range 0.7-266 mutations/Mb). A total of 14 cases (9.1%) were classified as having a low TMB (≤5 mutations/Mb), 64 of 154 (41.6%) had an intermediate TMB (>5 and ≤20 mutations/Mb), 40 of 154 (26.0%) had a high TMB (>20 and ≤50 mutations/Mb) and 36 of 154 (23.4%) were classified as having a very high TMB (>50 mutations/Mb). NRAS mutant melanoma demonstrated significantly decreased overall survival on multivariable analysis (HR for death 2.95, 95% CI 1.13-7.69, p = 0.027, log-rank test) compared with other TCGA molecular subgroups. Of the 116 patients in our cohort with available treatment data, 36 received a combination of dual ICI with anti-CTLA4 and anti-PD1 inhibition as first-line therapy. Elevated TMB was associated with significantly longer progression-free survival following dual-agent ICI (HR 0.26, 95% CI 0.07-0.90, p = 0.033, log-rank test).

CONCLUSIONS

NRAS mutation in CMs correlated with significantly worse overall survival. Elevated TMB was associated with increased progression-free survival for patients treated with a combination of dual ICI, supporting the potential utility of TMB as a predictive biomarker for ICI response in melanoma.

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.

Role of Surgery in Metastatic Melanoma and Review of Melanoma Molecular Characteristics

We aimed to review the molecular characteristics of metastatic melanoma and the role of surgery in metastasectomy for metastatic melanoma. We performed a systematic literature search on PubMed to identify relevant studies focusing on several mutations, including NRAS, BRAF, NF1, MITF, PTEN, TP53, CDKN2A, TERT, TMB, EGFR, and c-KIT. This was performed in the context of metastatic melanoma and the role of metastasectomy in the metastatic melanoma population. A comprehensive review of these molecular characteristics is presented with a focus on their prognosis and role in surgical metastasectomy.

What Is the Timing and Role of Targeted Therapy in Metastatic Melanoma?

ABSTRACT

Melanoma is the most lethal cutaneous malignancy worldwide. The last 15 years have ushered in several regulatory approvals that have dramatically altered the landscape of treatment options for patients with melanoma. Many patients with melanoma harbor activating mutations in the BRAF proto-oncogene, a key component of the mitogen-activated protein kinase (MAPK) intracellular signaling pathway. Therapies targeting BRAF have led to remarkable improvements in both response rates and survival in patients with metastatic disease. In parallel with these developments in MAPK-targeted therapy has been the clinical development of immune checkpoint inhibitors, which also have improved response rates and survival in patients with metastatic disease including randomized trials compared with MAPK-targeted therapy in patients with advanced, BRAF-mutant melanoma. Immune checkpoint inhibitors have become the preferred first-line standard-of-care treatment for patients with newly diagnosed metastatic disease in patients irrespective of BRAF mutational status. Given these developments, it is now less clear how to optimize the use of MAPK-targeted therapy regarding treatment setting and in sequence with immune checkpoint inhibitor.

Prognostic and predictive biomarkers in melanoma

Biomarkers help to inform the clinical management of patients with melanoma. For patients with clinically localised primary melanoma, biomarkers can help to predict post-surgical outcome (including via the use of risk prediction tools), better select patients for sentinel lymph node biopsy, and tailor catch-all follow-up protocols to the individual. Systemic drug treatments, including immune checkpoint inhibitor (ICI) therapies and BRAF-targeted therapies, have radically improved the prognosis of metastatic (stage III and IV) cutaneous melanoma patients, and also shown benefit in the earlier setting of stage IIB/C primary melanoma. Unfortunately, a response is far from guaranteed. Here, we review clinically relevant, established, and emerging, prognostic, and predictive pathological biomarkers that refine clinical decision-making in primary and metastatic melanoma patients. Gene expression profile assays and nomograms are emerging tools for prognostication and sentinel lymph node risk prediction in primary melanoma patients. Biomarkers incorporated into clinical practice guidelines include BRAF V600 mutations for the use of targeted therapies in metastatic cutaneous melanoma, and the HLA-A∗02:01 allele for the use of a bispecific fusion protein in metastatic uveal melanoma. Several predictive biomarkers have been proposed for ICI therapies but have not been incorporated into Australian clinical practice guidelines. Further research, validation, and assessment of clinical utility is required before more prognostic and predictive biomarkers are fluidly integrated into routine care.

Augmenting MEK inhibitor efficacy in BRAF wild-type melanoma: synergistic effects of disulfiram combination therapy

BACKGROUND

MEK inhibitors (MEKi) were shown to be clinically insufficiently effective in patients suffering from BRAF wild-type (BRAF WT) melanoma, even if the MAPK pathway was constitutively activated due to mutations in NRAS or NF-1. Thus, novel combinations are needed to increase the efficacy and duration of response to MEKi in BRAF WT melanoma. Disulfiram and its metabolite diethyldithiocarbamate are known to have antitumor effects related to cellular stress, and induction of endoplasmic reticulum (ER) stress was found to synergize with MEK inhibitors in NRAS-mutated melanoma cells. Therefore, we investigated the combination of both therapeutics to test their effects on BRAF-WT melanoma cells and compared them with monotherapy using the MEKi trametinib.

METHODS

The effects of combined therapy with disulfiram or its metabolite diethyldithiocarbamate and the MEKi trametinib were evaluated in a series of BRAF-WT melanoma cell lines by measuring cell viability and apoptosis induction. Cytotoxicity was additionally assessed in 3D spheroids, ex vivo melanoma slice cultures, and in vivo xenograft mouse models. The response of melanoma cells to treatment was studied at the RNA and protein levels to decipher the mode of action. Intracellular and intratumoral copper measurements were performed to investigate the role of copper ions in the antitumor cytotoxicity of disulfiram and its combination with the MEKi.

RESULTS

Diethyldithiocarbamate enhanced trametinib-induced cytotoxicity and apoptosis induction in 2D and 3D melanoma culture models. Mechanistically, copper-dependent induction of oxidative stress and ER stress led to Janus kinase (JNK)-mediated apoptosis in melanoma cells. This mechanism was also detectable in patient-derived xenograft melanoma models and resulted in a significantly improved therapeutic effect compared to monotherapy with the MEKi trametinib.

CONCLUSIONS

Disulfiram and its metabolite represent an attractive pharmaceutical approach to induce ER stress in melanoma cells that potentiates the antitumor effect of MEK inhibition and may be an interesting candidate for combination therapy of BRAF WT melanoma.

Predictive Factors in Metastatic Melanoma Treated with Immune Checkpoint Inhibitors: From Clinical Practice to Future Perspective

The introduction of immunotherapy revolutionized the treatment landscape in metastatic melanoma. Despite the impressive results associated with immune checkpoint inhibitors (ICIs), only a portion of patients obtain a response to this treatment. In this scenario, the research of predictive factors is fundamental to identify patients who may have a response and to exclude patients with a low possibility to respond. These factors can be host-associated, immune system activation-related, and tumor-related. Patient-related factors can vary from data obtained by medical history (performance status, age, sex, body mass index, concomitant medications, and comorbidities) to analysis of the gut microbiome from fecal samples. Tumor-related factors can reflect tumor burden (metastatic sites, lactate dehydrogenase, C-reactive protein, and circulating tumor DNA) or can derive from the analysis of tumor samples (driver mutations, tumor-infiltrating lymphocytes, and myeloid cells). Biomarkers evaluating the immune system activation, such as IFN-gamma gene expression profile and analysis of circulating immune cell subsets, have emerged in recent years as significantly correlated with response to ICIs. In this manuscript, we critically reviewed the most updated literature data on the landscape of predictive factors in metastatic melanoma treated with ICIs. We focus on the principal limits and potentiality of different methods, shedding light on the more promising biomarkers.

Combinatorial Treatment with PARP and MAPK Inhibitors Overcomes Phenotype Switch-Driven Drug Resistance in Advanced Melanoma

Metastatic melanoma is either intrinsically resistant or rapidly acquires resistance to targeted therapy treatments, such as MAPK inhibitors (MAPKi). A leading cause of resistance to targeted therapy is a dynamic transition of melanoma cells from a proliferative to a highly invasive state, a phenomenon called phenotype switching. Mechanisms regulating phenotype switching represent potential targets for improving treatment of patients with melanoma. Using a drug screen targeting chromatin regulators in patient-derived three-dimensional MAPKi-resistant melanoma cell cultures, we discovered that PARP inhibitors (PARPi) restore sensitivity to MAPKis, independent of DNA damage repair pathways. Integrated transcriptomic, proteomic, and epigenomic analyses demonstrated that PARPis induce lysosomal autophagic cell death, accompanied by enhanced mitochondrial lipid metabolism that ultimately increases antigen presentation and sensitivity to T-cell cytotoxicity. Moreover, transcriptomic and epigenetic rearrangements induced by PARP inhibition reversed epithelial-mesenchymal transition-like phenotype switching, which redirected melanoma cells toward a proliferative and MAPKi-sensitive state. The combination of PARP and MAPKis synergistically induced cancer cell death both in vitro and in vivo in patient-derived xenograft models. Therefore, this study provides a scientific rationale for treating patients with melanoma with PARPis in combination with MAPKis to abrogate acquired therapy resistance.

SIGNIFICANCE

PARP inhibitors can overcome resistance to MAPK inhibitors by activating autophagic cell death and reversing phenotype switching, suggesting that this synergistic combination could help improve the prognosis of patients with melanoma.

BRAF V600E Mutations and Beyond: A Molecular Perspective of Melanoma from a Tertiary Cancer Referral Center of India

Vaibhavi VengurlekarObjectives  Malignant melanoma demonstrates frequently occurring mutations of genes in the serine/threonine kinase pathway, namely BRAF, NRAS, and neurofibromin 1. There is rare documentation of a detailed analysis of these mutations in cases of melanoma among Indian patients. We present molecular features in cases of malignant melanoma, diagnosed at a tertiary cancer referral center in India, over a period of 8 years (2011-2018). Materials and Methods  This study was performed on formalin fixed paraffin embedded tissues of 88 histologically confirmed cases of malignant melanoma. BRAF gene alterations were studied by both Sanger sequencing and real-time polymerase chain reaction techniques ( n  = 74). Molecular testing for BRAF and NRAS gene alterations was accomplished in 74/88 cases (80%). Molecular test results were correlated with clinicopathological features using IBM SPSS Statistical software 25.0. Results  The age ranged from 13 to 79 years (median = 57), with a M:F ratio of 1.4:1. BRAF mutations were observed in 12/74 (16.21%) patients, including V600E ( n  = 7), A594T ( n  = 1), T599 = ( n  = 2), V600K ( n  = 1), and Q612P ( n  = 1), while NRAS mutations were observed in 6/38 (15.7%) patients. Among various subtypes, nodular melanoma was the most frequent subtype (33%) among cutaneous malignant melanomas. Among non-cutaneous melanomas, mucosal melanomas were observed in 37.5% of cases. Conclusion  This constitutes one of the few reports on comprehensive analysis of molecular alterations underlying melanomas in Indian patients. A larger sample size, with more extensive molecular markers, would yield additional information on the disease manifestation.

Dynamical modeling of proliferative-invasive plasticity and IFNγ signaling in melanoma reveals mechanisms of PD-L1 expression heterogeneity

BACKGROUND

Phenotypic heterogeneity of melanoma cells contributes to drug tolerance, increased metastasis, and immune evasion in patients with progressive disease. Diverse mechanisms have been individually reported to shape extensive intra-tumor and inter-tumor phenotypic heterogeneity, such as IFNγ signaling and proliferative to invasive transition, but how their crosstalk impacts tumor progression remains largely elusive.

METHODS

Here, we integrate dynamical systems modeling with transcriptomic data analysis at bulk and single-cell levels to investigate underlying mechanisms behind phenotypic heterogeneity in melanoma and its impact on adaptation to targeted therapy and immune checkpoint inhibitors. We construct a minimal core regulatory network involving transcription factors implicated in this process and identify the multiple 'attractors' in the phenotypic landscape enabled by this network. Our model predictions about synergistic control of PD-L1 by IFNγ signaling and proliferative to invasive transition were validated experimentally in three melanoma cell lines-MALME3, SK-MEL-5 and A375.

RESULTS

We demonstrate that the emergent dynamics of our regulatory network comprising MITF, SOX10, SOX9, JUN and ZEB1 can recapitulate experimental observations about the co-existence of diverse phenotypes (proliferative, neural crest-like, invasive) and reversible cell-state transitions among them, including in response to targeted therapy and immune checkpoint inhibitors. These phenotypes have varied levels of PD-L1, driving heterogeneity in immunosuppression. This heterogeneity in PD-L1 can be aggravated by combinatorial dynamics of these regulators with IFNγ signaling. Our model predictions about changes in proliferative to invasive transition and PD-L1 levels as melanoma cells evade targeted therapy and immune checkpoint inhibitors were validated in multiple RNA-seq data sets from in vitro and in vivo experiments.

CONCLUSION

Our calibrated dynamical model offers a platform to test combinatorial therapies and provide rational avenues for the treatment of metastatic melanoma. This improved understanding of crosstalk among PD-L1 expression, proliferative to invasive transition and IFNγ signaling can be leveraged to improve the clinical management of therapy-resistant and metastatic melanoma.

New Treatment Horizons in Uveal and Cutaneous Melanoma

Melanoma is a complex and heterogeneous malignant tumor with distinct genetic characteristics and therapeutic challenges in both cutaneous melanoma (CM) and uveal melanoma (UM). This review explores the underlying molecular features and genetic alterations in these melanoma subtypes, highlighting the importance of employing specific model systems tailored to their unique profiles for the development of targeted therapies. Over the past decade, significant progress has been made in unraveling the molecular and genetic characteristics of CM and UM, leading to notable advancements in treatment options. Genetic mutations in the mitogen-activated protein kinase (MAPK) pathway drive CM, while UM is characterized by mutations in genes like GNAQ, GNA11, BAP1, EIF1AX, and SF3B1. Chromosomal aberrations, including monosomy 3 in UM and monosomy 10 in CM, play significant roles in tumorigenesis. Immune cell infiltration differs between CM and UM, impacting prognosis. Therapeutic advancements targeting these genetic alterations, including oncolytic viruses and immunotherapies, have shown promise in preclinical and clinical studies. Oncolytic viruses selectively infect malignant cells, inducing oncolysis and activating antitumor immune responses. Talimogene laherparepvec (T-VEC) is an FDA-approved oncolytic virus for CM treatment, and other oncolytic viruses, such as coxsackieviruses and HF-10, are being investigated. Furthermore, combining oncolytic viruses with immunotherapies, such as CAR-T cell therapy, holds great potential. Understanding the intrinsic molecular features of melanoma and their role in shaping novel therapeutic approaches provides insights into targeted interventions and paves the way for more effective treatments for CM and UM.

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.

Immune checkpoint inhibition in patients with NRAS mutated and NRAS wild type melanoma: a multicenter Dermatologic Cooperative Oncology Group study on 637 patients from the prospective skin cancer registry ADOREG

BACKGROUND

Melanomas frequently harbour somatic mutations in BRAF (40%) or NRAS (20%). Impact of NRAS mutations on the therapeutic outcome of immune checkpoint inhibitors (ICI) remains controversial. Potential correlation of the NRAS mutational status and programmed cell death ligand-1 (PD-L1) expression in melanoma is unknown.

PATIENTS AND METHODS

Advanced, non-resectable melanoma patients with known NRAS mutation status treated with first-line ICI between 06/2014 and 05/2020 in the prospective multicenter skin cancer registry ADOREG were included. Overall response rate (ORR), progression-free survival (PFS), and overall survival (OS) according to NRAS status were analysed. A multivariate Cox model was used to analyse factors associated with PFS and OS; survival was analysed using the Kaplan-Meier approach.

RESULTS

Among 637 BRAF wild-type patients, 310 (49%) had an NRAS mutation with Q61R (41%) and Q61K (32%). NRAS-mutated (NRASmut) melanomas were significantly more often located on the lower extremities and trunk (p = 0.001); nodular melanoma was the most common subtype (p < 0.0001). No significant differences were found for PFS and OS for anti-PD1 monotherapy (2-year PFS 39%, [95% confidence interval (CI), 33-47] in NRASmut patients and 41% [95% CI, 35-48] in NRAS-wild type (NRASwt) patients; 2-year OS was 54% [95% CI, 48-61] in NRASmut patients and 57% [95% CI, 50-64] in NRASwt patients) and anti-PD1 plus anti-CTLA4 therapy between both cohorts (2-year PFS was 54% [95% CI, 44-66] in NRASmut patients and 53% [95% CI, 41-67] in NRASwt patients; 2-year OS was 58% [95% CI, 49-70] in NRASmut patients and 62% [95% CI, 51-75] in NRASwt patients). The ORR to anti-PD1 was 35% for NRASwt patients and 26% for NRASmut patients and 34% compared to 32% for combinational therapy. Data on PD-L1 expression was available in 82 patients (13%). PD-L1 expression (>5%) was not correlated to NRAS mutational status. In multivariate analysis, elevated lactate dehydrogenase, Eastern Cooperative Oncology Group performance status ≥ 1, and brain metastases were significantly associated with a higher risk of death in all patients.

CONCLUSIONS

The PFS and OS were not affected by NRAS mutational status in patients treated with anti-PD1-based ICI. Similar ORR was seen in NRASwt and NRASmut patients. Tumour PD-L1 expression did not correlate with NRAS mutational status.

Pathology and Molecular Biology of Melanoma

Almost every death in young patients with an advanced skin tumor is caused by melanoma. Today, with the help of modern treatments, these patients survive longer or can even achieve a cure. Advanced stage melanoma is frequently related with poor prognosis and physicians still find this disease difficult to manage due to the absence of a lasting response to initial treatment regimens and the lack of randomized clinical trials in post immunotherapy/targeted molecular therapy settings. New therapeutic targets are emerging from preclinical data on the genetic profile of melanocytes and from the identification of molecular factors involved in the pathogenesis of malignant transformation. In the current paper, we present the diagnostic challenges, molecular biology and genetics of malignant melanoma, as well as the current therapeutic options for patients with this diagnosis.

Methoxylated Cinnamic Esters with Antiproliferative and Antimetastatic Effects on Human Lung Adenocarcinoma Cells

Lung cancer is the leading cause of cancer mortality worldwide, and malignant melanomas are highly lethal owing to their elevated metastatic potential. Despite improvements in therapeutic approaches, cancer treatments are not completely effective. Thus, new drug candidates are continuously sought. We synthesized mono- and di-methoxylated cinnamic acid esters and investigated their antitumor potential. A cell viability assay was performed to identify promising substances against A549 (non-small-cell lung cancer) and SK-MEL-147 (melanoma) cells. (E)-2,5-dimethoxybenzyl 3-(4-methoxyphenyl)acrylate (4m), a monomethoxylated cinnamic acid derivative, was identified as the lead antitumor compound, and its antitumor potential was deeply investigated. Various approaches were employed to investigate the antiproliferative (clonogenic assay and cell cycle analysis), proapoptotic (annexin V assay), and antimigratory (wound-healing and adhesion assays) activities of 4m on A549 cells. In addition, western blotting was performed to explore its mechanism of action. We demonstrated that 4m inhibits the proliferation of A549 by promoting cyclin B downregulation and cell cycle arrest at G2/M. Antimigratory and proapoptotic activities of 4m on A549 were also observed. The antitumor potential of 4m involved its ability to modulate the mitogen-activated protein kinases/extracellular signal-regulated kinase (MAPK/ERK) signaling pathway once phosphorylated-ERK expression was considerably reduced in response to treatment. Our findings demonstrate that 4m is a promising anticancer drug candidate.

Dynamical modelling of proliferative-invasive plasticity and IFNγ signaling in melanoma reveals mechanisms of PD-L1 expression heterogeneity

Phenotypic heterogeneity of melanoma cells contributes to drug tolerance, increased metastasis, and immune evasion in patients with progressive disease. Diverse mechanisms have been individually reported to shape extensive intra- and inter-tumoral phenotypic heterogeneity, such as IFNγ signaling and proliferative to invasive transition, but how their crosstalk impacts tumor progression remains largely elusive. Here, we integrate dynamical systems modeling with transcriptomic data analysis at bulk and single-cell levels to investigate underlying mechanisms behind phenotypic heterogeneity in melanoma and its impact on adaptation to targeted therapy and immune checkpoint inhibitors. We construct a minimal core regulatory network involving transcription factors implicated in this process and identify the multiple "attractors" in the phenotypic landscape enabled by this network. Our model predictions about synergistic control of PD-L1 by IFNγ signaling and proliferative to invasive transition were validated experimentally in three melanoma cell lines - MALME3, SK-MEL-5 and A375. We demonstrate that the emergent dynamics of our regulatory network comprising MITF, SOX10, SOX9, JUN and ZEB1 can recapitulate experimental observations about the co-existence of diverse phenotypes (proliferative, neural crest-like, invasive) and reversible cell-state transitions among them, including in response to targeted therapy and immune checkpoint inhibitors. These phenotypes have varied levels of PD-L1, driving heterogeneity in immune-suppression. This heterogeneity in PD-L1 can be aggravated by combinatorial dynamics of these regulators with IFNγ signaling. Our model predictions about changes in proliferative to invasive transition and PD-L1 levels as melanoma cells evade targeted therapy and immune checkpoint inhibitors were validated in multiple data sets from in vitro and in vivo experiments. Our calibrated dynamical model offers a platform to test combinatorial therapies and provide rational avenues for the treatment of metastatic melanoma. This improved understanding of crosstalk among PD-L1 expression, proliferative to invasive transition and IFNγ signaling can be leveraged to improve the clinical management of therapy-resistant and metastatic melanoma.

Epidemiological and clinical characterization of a population-based cohort of cutaneous malignant melanoma patients in the South Region of Portugal

An historical population-based cohort study was conducted aiming to estimate the incidence of cutaneous malignant melanoma in the South Region of Portugal between Jan 2016 and June 2017; to clinically characterize the diagnosed individuals; to describe instituted treatment; and to estimate survival outcomes. Data were extracted from a cancer registry (ROR-Sul) covering 4,800,000 inhabitants (46% of the Portuguese population) and included a total of 789 individuals meeting eligibility criteria. The crude incidence rate (18 months) of melanoma was 13.36/100,000 inhabitants and the Age-Standardized Incidence Rate per 100,000 World population was 9.65/100,000 inhabitants. The most common histological subtypes identified were superficial extension, followed by malignant melanoma and nodular melanoma. Most cases were diagnosed in stage I (50.39%), equally distributed by sex and with a median age of 65 years. During the study period, 174 recurrence events were recorded (23.45%) and recurrence-free survival rate was significantly lower in more advanced stages. Patients had a two-fold risk of recurrence/death when in presence of ulcerated tumors [adjusted hazard ratio (adj HR) = 2.28; 95% confidence interval (CI) 1.40-3.70]. Overall survival rate at 3-years was 80.54% (95% CI 77.58-83.15), higher than previous national reports, and considerably higher for individuals diagnosed at earlier stages (p < 0.001). We have also identified differential survival outcomes in stages II-III explained by the uptake of sentinel lymph node biopsy. The epidemiologic and clinical characteristics of malignant melanoma patients studied are consistent with international literature. The incidence and rates observed suggests additional public health campaigns are needed to modify behaviours of the Portuguese population and thus reduce their risk.

Initial Evidence for the Efficacy of Naporafenib in Combination With Trametinib in NRAS-Mutant Melanoma: Results From the Expansion Arm of a Phase Ib, Open-Label Study

PURPOSE

No approved targeted therapy for the treatment of patients with neuroblastoma RAS viral (v-ras) oncogene homolog (NRAS)-mutant melanoma is currently available.

PATIENTS AND METHODS

In this phase Ib escalation/expansion study (ClinicalTrials.gov identifier: NCT02974725), the safety, tolerability, and preliminary antitumor activity of naporafenib (LXH254), a BRAF/CRAF protein kinases inhibitor, were explored in combination with trametinib in patients with advanced/metastatic KRAS- or BRAF-mutant non-small-cell lung cancer (escalation arm) or NRAS-mutant melanoma (escalation and expansion arms).

RESULTS

Thirty-six and 30 patients were enrolled in escalation and expansion, respectively. During escalation, six patients reported grade ≥3 dose-limiting toxicities, including dermatitis acneiform (n = 2), maculopapular rash (n = 2), increased lipase (n = 1), and Stevens-Johnson syndrome (n = 1). The recommended doses for expansion were naporafenib 200 mg twice a day plus trametinib 1 mg once daily and naporafenib 400 mg twice a day plus trametinib 0.5 mg once daily. During expansion, all 30 patients experienced a treatment-related adverse event, the most common being rash (80%, n = 24), blood creatine phosphokinase increased, diarrhea, and nausea (30%, n = 9 each). In expansion, the objective response rate, median duration of response, and median progression-free survival were 46.7% (95% CI, 21.3 to 73.4; 7 of 15 patients), 3.75 (95% CI, 1.97 to not estimable [NE]) months, and 5.52 months, respectively, in patients treated with naporafenib 200 mg twice a day plus trametinib 1 mg once daily, and 13.3% (95% CI, 1.7 to 40.5; 2 of 15 patients), 3.75 (95% CI, 2.04 to NE) months, and 4.21 months, respectively, in patients treated with naporafenib 400 mg twice a day plus trametinib 0.5 mg once daily.

CONCLUSION

Naporafenib plus trametinib showed promising preliminary antitumor activity in patients with NRAS-mutant melanoma. Prophylactic strategies aimed to lower the incidence of skin-related events are under investigation.

Incidence of BRAF mutations in cutaneous melanoma: histopathological and molecular analysis of a Ukrainian population

Aim

This study aimed to investigate the incidence of BRAF mutation in cutaneous melanoma in the Ukrainian population with respect to clinical and histopathological data.

Materials & methods

This single-center retrospective cohort study enrolled 299 primary CM with known BRAF status assessed by RT-PCR.

Results

The overall BRAF mutation rate was 56.5% in CM and demonstrated a link with the younger age (p < 0.001), anatomical site (p < 0.001) and histological type of CM (p = 0.022). BRAF-positive CM possessed a slightly higher mitotic rate (p = 0.015) and Breslow thickness (p = 0.028) but did not relate to tumor-infiltrating lymphocytes.

Conclusion

The high rate of BRAF mutations in CM patients in the Ukrainian cohort was associated with superficial spreading histology, higher depth of invasion and proliferation.

Antiangiogenic activity of the penicillin derivative TAP7f in melanoma

Previously , we demonstrated that the non-antibiotic penicillin derivative TAP7f inhibited melanoma metastasis in vitro and in vivo through the downregulation of β-catenin and integrin αVβ3. As angiogenesis is required for tumor growth and metastasis, we decided to explore the possible antiangiogenic effect of TAP7f. We found that TAP7f inhibited proliferation, migration, tube formation, and actin cytoskeleton organization of human endothelial cells. In a gel plug assay, an in vivo model for angiogenesis, TAP7f also blocked vascular formation induced by fibroblast growth factor 2. Furthermore, when murine B16-F10 melanoma cells pre-treated with TAP7f were injected intradermally in mice, we observed a decrease in the number and thickness of the capillaries surrounding the tumor. Additionally, TAP7f downregulated vascular endothelial growth factor (VEGF) and platelet-derived growth factor-B (PDGF-B) expression in B16-F10 cells and VEGF receptor expression in HMEC-1 endothelial cells. When the antitumor effect of TAP7f was studied in C57BL/6 J mice challenged with B16-F10 melanoma cells, a significant reduction of tumor growth was observed. Furthermore, a decreased expression of VEGF, PDGF-B, and the endothelial cell marker CD34 was observed in tumors from TAP7f-treated mice. Together, our results suggest that the antiangiogenic activity of TAP7f contributes to its antitumor and antimetastatic action and positions this penicillin derivative as an alternative or complementary agent for the treatment of melanoma. KEY MESSAGES: • TAP7f inhibits proliferation, migration, tube formation, and actin cytoskeleton organization of endothelial cells. • TAP7f downregulates VEGF receptor expression in endothelial cells. • TAP7f downregulates VEGF and PDGF expression in melanoma cells. • TAP7f inhibits angiogenesis in vivo.

Piperine-Chlorogenic Acid Hybrid Inhibits the Proliferation of the SK-MEL-147 Melanoma Cells by Modulating Mitotic Kinases

Melanoma is considered the most aggressive form of skin cancer, showing high metastatic potential and persistent high mortality rates despite the introduction of immunotherapy and targeted therapies. Thus, it is important to identify new drug candidates for melanoma. The design of hybrid molecules, with different pharmacophore fragments combined in the same scaffold, is an interesting strategy for obtaining new multi-target and more effective anticancer drugs. We designed nine hybrid compounds bearing piperine and chlorogenic acid pharmacophoric groups and evaluated their antitumoral potential on melanoma cells with distinct mutational profiles SK-MEL-147, CHL-1 and WM1366. We identified the compound named PQM-277 (3a) to be the most cytotoxic one, inhibiting mitosis progression and promoting an accumulation of cells in pro-metaphase and metaphase by altering the expression of genes that govern G2/M transition and mitosis onset. Compound 3a downregulated FOXM1, CCNB1, CDK1, AURKA, AURKB, and PLK1, and upregulated CDKN1A. Molecular docking showed that 3a could interact with the CUL1-RBX1 complex, which activity is necessary to trigger molecular events essential for FOXM1 transactivation and, in turn, G2/M gene expression. In addition, compound 3a effectively induced apoptosis by increasing BAX/BCL2 ratio. Our findings demonstrate that 3a is an important antitumor candidate prototype and support further investigations to evaluate its potential for melanoma treatment, especially for refractory cases to BRAF/MEK inhibitors.

Melatonin as a Repurposed Drug for Melanoma Treatment

Melanoma is the most aggressive type of skin cancer, with a greater risk of metastasis and a higher prevalence and mortality rate. This cancer type has been demonstrated to develop resistance to the known treatment options such as conventional therapeutic agents and targeted therapy that are currently being used as the standard of care. Drug repurposing has been explored as a potential alternative treatment strategy against disease pathophysiologies, including melanoma. To that end, multiple studies have suggested that melatonin produced by the pineal gland possesses anti-proliferative and oncostatic effects in experimental melanoma models. The anticarcinogenic activity of melatonin is attributed to its ability to target a variety of oncogenic signaling pathways, including the MAPK pathways which are involved in regulating the behavior of cancer cells, including cell survival and proliferation. Additionally, preclinical studies have demonstrated that melatonin in combination with chemotherapeutic agents exerts synergistic effects against melanoma. The goal of this review is to highlight the mechanistic insights of melatonin as a monotherapy or combinational therapy for melanoma treatment.

Case report: Therapeutic potential of T-VEC in combination with MEK inhibitors in melanoma patients with NRAS mutation

Mutations in the NRAS gene are common alterations in malignant melanoma. However, there are no specific treatment options approved for NRAS-mutated melanoma patients besides immune checkpoint inhibition. Since preclinical data suggests a synergistic effect of a MEK inhibitor (MEKi) and the oncolytic virus talimogene laherparepvec (T-VEC), we have treated three melanoma patients with this combination. All of the three patients had been suffering from recurring cutaneous and subcutaneous in-transit metastases. Upon treatment one patient (case 1) presented full regression of locoregional metastases and remained progression-free until date, for almost three years. The second patient (case 2) showed a partial regression of painful gluteal satellite metastases but died from brain metastases. The third patient (case 3) showed a durable response of locoregional metastases for seven months. The combination treatment was well tolerated with common adverse events known for each single agent. This report is the first case series presenting a clinical benefit of the combined T-VEC and MEKi treatment. We suggest the combination of T-VEC and MEKi as an off-label treatment option for patients with NRAS mutations, especially with recurrent in-transit or satellite metastases.

Melanogenesis and the Targeted Therapy of Melanoma

Pigment production is a unique character of melanocytes. Numerous factors are linked with melanin production, including genetics, ultraviolet radiation (UVR) and inflammation. Understanding the mechanism of melanogenesis is crucial to identify new preventive and therapeutic strategies in the treatment of melanoma. Here, we reviewed the current available literatures on the mechanisms of melanogenesis, including the signaling pathways of UVR-induced pigment production, MC1R's central determinant roles and MITF as a master transcriptional regulator in melanogenesis. Moreover, we further highlighted the role of targeting BRAF, NRAS and MC1R in melanoma prevention and treatment. The combination therapeutics of immunotherapy and targeted kinase inhibitors are becoming the newest therapeutic option in advanced melanoma.

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.

Crosstalk of four kinds of cell deaths defines subtypes of cutaneous melanoma for precise immunotherapy and chemotherapy

Background

Cell death patterns can give therapeutic and biological clues that facilitate the development of individualized treatments for this lethal form of skin cancer.

Methods

We employed unsupervised clustering to establish robust classifications based on the four kinds of cell death-associated gene expression of 462 melanoma patients in the Cancer Genome Atlas (TCGA) and tested their reproducibility in two independent melanoma cohorts of 558 patients. We then used dimensionality reduction of graph learning to display the different characteristics of cell death patterns and immune microenvironments.

Results

We examined 570 cell death-associated gene expression data of melanoma patients for exploration, independent verification, and comprehensive classification of five reproducible melanoma subtypes (CS1 to CS5) with different genomic and clinical features. Patients in death-inactive subtypes (CS1, CS2, and CS5) had the least immune and stromal cell infiltration, and their prognosis was the poorest. A death-active subtype (CS4), on the other hand, had the highest infiltrated immune and stromal cells and elevated immune-checkpoints. As a result, these patients had the highest response to immunotherapy and the best prognosis. An additional subtype (CS3) had more diversified cell death and immune characteristics with moderate prognoses. Based on graph learning, we successfully divided the CS3 subtype into two subgroups (group A and group B) with distinct survival outcomes and immune features. Finally, we identified eight potential chemical drugs that were specifically targeted for the therapy of melanoma subtypes.

Conclusions

This research defines the intrinsic subtypes of melanoma based on the crosstalk of four kinds of cell deaths, which affords a blueprint for clinical strategies and guiding precise immunotherapy and chemotherapy for melanoma patients.

Decoding molecular programs in melanoma brain metastases

Melanoma brain metastases (MBM) variably respond to therapeutic interventions; thus determining patient's prognosis. However, the mechanisms that govern therapy response are poorly understood. Here, we use a multi-OMICS approach and targeted sequencing (TargetSeq) to unravel the programs that potentially control the development of progressive intracranial disease. Molecularly, the expression of E-cadherin (Ecad) or NGFR, the BRAF mutation state and level of immune cell infiltration subdivides tumors into proliferative/pigmented and invasive/stem-like/therapy-resistant irrespective of the intracranial location. The analysis of MAPK inhibitor-naive and refractory MBM reveals switching from Ecad-associated into NGFR-associated programs during progression. NGFR-associated programs control cell migration and proliferation via downstream transcription factors such as SOX4. Moreover, global methylome profiling uncovers 46 differentially methylated regions that discriminate BRAF^mut and wildtype MBM. In summary, we propose that the expression of Ecad and NGFR sub- classifies MBM and suggest that the Ecad-to-NGFR phenotype switch is a rate-limiting process which potentially indicates drug-response and intracranial progression states in melanoma patients.

Cumulative incidence and risk factors of brain metastasis for acral and mucosal melanoma patients with stages I-III

PURPOSE

Few studies focused on the incidence of brain metastasis in patients with acral and mucosal melanoma, and a better understanding of the incidences and predictors of brain metastasis is needed in these patients.

METHOD

A prospectively accrued cohort of 799 patients with acral and mucosal melanoma in stages I-III from July 2011 to December 2015 at Peking University Cancer Hospital were included in this study. Competing risk models (Fine and Gray) were used to estimate the cumulative incidence of brain metastasis and compare the differences in cumulative incidence curves between different primary lesions, stages, and molecular types.

RESULTS

At a median follow-up time of 68.0 months, 60 of the 779 patients (7.7%) developed brain metastasis, and 261 (33.5%) patients developed extracranial metastasis. Considering the risk of competition, the cumulative incidence of brain metastasis at one year, two years, and five years after diagnosis were 5.1%, 10.2%, and 19.5%, respectively. Stage III, BRAF mutations, and NRAS mutations were associated with a high risk of brain metastasis in univariable analysis. Multivariate analysis showed BRAF mutations, and NRAS mutations had statistically correlated with an increased cumulative incidence of brain metastasis at diagnosis and all-time point of one year and two years after diagnosis.

CONCLUSION

This study is the first to report the cumulative incidence and risk factors of brain metastasis for patients with acral and mucosal melanoma in stages I-III. Patients with BRAF and NRAS mutations had a higher incidence at diagnosis and all-time point, providing the basis for surveillance guidelines and further mechanic exploration.

Prognostic biomarkers of cutaneous melanoma

BACKGROUND/PURPOSE

Melanomas account for only approximately 4% of diagnosed skin cancers in the United States but are responsible for the majority of deaths caused by skin cancer. Both genetic factors and ultraviolet (UV) radiation exposure play a role in the development of melanoma. Although melanomas have a strong propensity to metastasize when diagnosed late, melanomas that are diagnosed and treated early pose a low mortality risk. In particular, the identification of patients with increased metastatic risk, who may benefit from early adjuvant therapies, is crucial, especially given the advent of new melanoma treatments. However, the accuracy of classic clinical and histological variables, including the Breslow thickness, presence of ulceration, and lymph node status, might not be sufficient to identify such individuals. Thus, there is a need for the development of additional prognostic melanoma biomarkers that can improve early attempts to stratify melanoma patients and reliably identify high-risk subgroups with the aim of providing effective personalized therapies.

METHODS

In our current work, we discuss and assess emerging primary melanoma tumor biomarkers and prognostic circulating biomarkers.

RESULTS

Several promising biomarkers show prognostic value (eg, exosomal MIA (ie, melanoma inhibitory activity), serum S100B, AMLo signatures, and mRNA signatures); however, the scarcity of reliable data precludes the use of these biomarkers in current clinical applications.

CONCLUSION

Further research is needed on several promising biomarkers for melanoma. Large-scale studies are warranted to facilitate the clinical translation of prognostic biomarker applications for melanoma in personalized medicine.

Skin Cancer Research Goes Digital: Looking for Biomarkers within the Droplets

Skin cancer, which includes the most frequent malignant non-melanoma carcinomas (basal cell carcinoma, BCC, and squamous cell carcinoma, SCC), along with the difficult to treat cutaneous melanoma (CM), pose important worldwide issues for the health care system. Despite the improved anti-cancer armamentarium and the latest scientific achievements, many skin cancer patients fail to respond to therapies, due to the remarkable heterogeneity of cutaneous tumors, calling for even more sophisticated biomarker discovery and patient monitoring approaches. Droplet digital polymerase chain reaction (ddPCR), a robust method for detecting and quantifying low-abundance nucleic acids, has recently emerged as a powerful technology for skin cancer analysis in tissue and liquid biopsies (LBs). The ddPCR method, being capable of analyzing various biological samples, has proved to be efficient in studying variations in gene sequences, including copy number variations (CNVs) and point mutations, DNA methylation, circulatory miRNome, and transcriptome dynamics. Moreover, ddPCR can be designed as a dynamic platform for individualized cancer detection and monitoring therapy efficacy. Here, we present the latest scientific studies applying ddPCR in dermato-oncology, highlighting the potential of this technology for skin cancer biomarker discovery and validation in the context of personalized medicine. The benefits and challenges associated with ddPCR implementation in the clinical setting, mainly when analyzing LBs, are also discussed.

The Genetics of Early-Stage Melanoma in a Veteran Population

To improve understanding of the genetic signature of early-stage melanomas in Veterans, hotspot mutation profiling using next-generation sequencing (NGS) was performed on melanoma tissue samples from patients at the Iowa City Veterans Affairs Medical Center (VAMC). Genetic analysis identified BRAF (36.3%), TP53 (25.9%), NRAS (19.3%), CDKN2A (11.1%), KIT (8.1%), and BAP1 (7.4%) mutations with the highest prevalence. Although common variants in BRAF were detected at lower rates than what is reported for the general population, 55.6% of cases showed activating mutations in the RAS/RAF pathways. Variants in TP53 and KIT were detected at higher rates than in the general population. Veterans with prior history of melanoma were at significantly higher odds of having TP53 mutation (OR = 2.67, p = 0.04). This suggests that TP53 may be a marker for recurrent melanoma and possibly alternative exposures in the military population. This study provides new information regarding the genetics of melanoma in a Veteran population and early-stage melanomas, highlighting risk factors unique to this population and contributing to the conversation about preventing melanoma deaths in US Military personnel.

Mefloquine induces ER stress and apoptosis in BRAFi-resistant A375-BRAFV600E /NRASQ61K malignant melanoma cells targeting intracranial tumors in a bioluminescent murine model

Molecularly targeted therapeutics have revolutionized the treatment of BRAFV600E -driven malignant melanoma, but the rapid development of resistance to BRAF kinase inhibitors (BRAFi) presents a significant obstacle. The use of clinical antimalarials for the investigational treatment of malignant melanoma has shown only moderate promise, attributed mostly to inhibition of lysosomal-autophagic adaptations of cancer cells, but identification of specific antimalarials displaying single-agent antimelanoma activity has remained elusive. Here, we have screened a focused library of clinically used artemisinin-combination therapeutic (ACT) antimalarials for the apoptotic elimination of cultured malignant melanoma cell lines, also examining feasibility of overcoming BRAFi-resistance comparing isogenic melanoma cells that differ only by NRAS mutational status (BRAFi-sensitive A375-BRAFV600E /NRASQ61 vs. BRAFi-resistant A375-BRAFV600E /NRASQ61K ). Among ACT antimalarials tested, mefloquine (MQ) was the only apoptogenic agent causing melanoma cell death at low micromolar concentrations. Comparative gene expression-array analysis (A375-BRAFV600E /NRASQ61 vs. A375-BRAFV600E /NRASQ61K ) revealed that MQ is a dual inducer of endoplasmic reticulum (ER) and redox stress responses that precede MQ-induced loss of viability. ER-trackerTM DPX fluorescence imaging and electron microscopy indicated ER swelling, accompanied by rapid induction of ER stress signaling (phospho-eIF2α, XBP-1s, ATF4). Fluo-4 AM-fluorescence indicated the occurrence of cytosolic calcium overload observable within seconds of MQ exposure. In a bioluminescent murine model employing intracranial injection of A375-Luc2 (BRAFV600E /NRASQ61K ) cells, an oral MQ regimen efficiently antagonized brain tumor growth. Taken together, these data suggest that the clinical antimalarial MQ may be a valid candidate for drug repurposing aiming at chemotherapeutic elimination of malignant melanoma cells, even if metastasized to the brain and BRAFi-resistant.

BRAF V600E Expression in Primary Melanoma and Its Association With Death: A Population-Based, Retrospective, Cross-Sectional Study

Approximately 50% of melanomas contain BRAF mutations; the effects on survival are unclear. We aimed to determine whether mutant BRAF expression in melanoma differs according to age, sex, and melanoma-specific survival. A total of 638 patients who resided in Olmsted County, Minnesota, with a first lifetime diagnosis of melanoma between 1970 and 2009 were identified from the Rochester Epidemiology Project (REP). Available tissue was analyzed for a BRAF V600E mutation with immunohistochemistry.

Preclinical Development of Seriniquinones as Selective Dermcidin Modulators for the Treatment of Melanoma

The bioactive natural product seriniquinone was discovered as a potential melanoma drug, which was produced by the as-yet-undescribed marine bacterium of the rare genus Serinicoccus. As part of a long-term research program aimed at the discovery of new agents for the treatment of cancer, seriniquinone revealed remarkable in vitro activity against a diversity of cancer cell lines in the US National Cancer Institute 60-cell line screening. Target deconvolution studies defined the seriniquinones as a new class of melanoma-selective agents that act in part by targeting dermcidin (DCD). The targeted DCD peptide has been recently examined and defined as a “pro-survival peptide” in cancer cells. While DCD was first isolated from human skin and thought to be only an antimicrobial peptide, currently DCD has been also identified as a peptide associated with the survival of cancer cells, through what is believed to be a disulfide-based conjugation with proteins that would normally induce apoptosis. However, the significantly enhanced potency of seriniquinone was of particular interest against the melanoma cell lines assessed in the NCI 60-cell line panel. This observed selectivity provided a driving force that resulted in a multidimensional program for the discovery of a usable drug with a new anticancer target and, therefore, a novel mode of action. Here, we provided an overview of the discovery and development efforts to date.

DEPTH2: an mRNA-based algorithm to evaluate intratumor heterogeneity without reference to normal controls

Background

Intratumor heterogeneity (ITH) is associated with tumor progression, unfavorable prognosis, immunosuppression, genomic instability, and therapeutic resistance. Thus, evaluation of ITH levels is valuable in cancer diagnosis and treatment.

Methods

We proposed a new mRNA-based ITH evaluation algorithm (DEPTH2) without reference to normal controls. DEPTH2 evaluates ITH levels based on the standard deviations of absolute z-scored transcriptome levels in tumors, reflecting the asynchronous level of transcriptome alterations relative to the central tendency in a tumor.

Results

By analyzing 33 TCGA cancer types, we demonstrated that DEPTH2 ITH was effective in measuring ITH for its significant associations with tumor progression, unfavorable prognosis, genomic instability, reduced antitumor immunity and immunotherapy response, and altered drug response in diverse cancers. Compared to other five ITH evaluation algorithms (MATH, PhyloWGS, ABSOLUTE, DEPTH, and tITH), DEPTH2 ITH showed a stronger association with unfavorable clinical outcomes, and in characterizing other properties of ITH, such as its associations with genomic instability and antitumor immunosuppression, DEPTH2 also displayed competitive performance.

Conclusions

DEPTH2 is expected to have a wider spectrum of applications in evaluating ITH in comparison to other algorithms.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03355-1.

The Prognostic Value of miR-125b, miR-200c and miR-205 in Primary Cutaneous Malignant Melanoma Is Independent of BRAF Mutational Status

Simple Summary

Melanoma accounts for the majority of skin cancer-related deaths. On the one hand, most melanomas contain mutations in the BRAF gene (predominantly V600E), and on the other hand, miRNAs modulate different steps in melanoma development and progression, but there are no reports that study the relation between BRAF mutational status and the expression of miRNAs, which is important for an accurate patient prognosis. The aim of our retrospective study was to know whether BRAF mutations influence the prognostic value of miR-125b, miR-200c and miR-205 intratumoral expression in primary cutaneous melanomas. Globally, our results showed that miR-125b, miR-200c and miR-205 expression predicted the clinical outcome of primary melanomas independently of BRAF status. Thus, our findings support that BRAF mutations alone do not predict the risk of metastasis development or melanoma survival and that miR-125b, miR-200c and miR-205 may be considered as accurate prognostic biomarkers in melanoma regardless of BRAF mutational status.

Abstract

BRAF mutations are present in around 50% of cutaneous malignant melanomas and are related to a poor outcome in advanced-stage melanoma patients. miRNAs are epigenetic regulators that modulate different cellular processes in cancer, including melanoma development and progression. However, there are no studies on the potential associations of the genetic alterations of the BRAF gene with miRNA expression in primary cutaneous melanomas. Here, in order to analyze the influence of BRAF mutations in the ability of selected miRNAs to predict clinical outcome and patient survival at the time of diagnosis, we studied the prognostic value of miR-125b, miR-200c and miR-205 expression depending on the BRAF mutational status in fresh, frozen primary tumor specimens. For this purpose, RNA was extracted for studying both BRAF mutations by Sanger sequencing and miRNA expression. Our results indicate that, although there seems to be a slight preference for their predictive ability in the BRAF mutated group, the expression of these three miRNAs serves effectively to predict the clinical outcome of melanoma patients independently of BRAF mutational status at the time of primary tumor diagnosis.

Prophylactic vaccines against cancers of non-infectious origin: a dream or a real possibility?

The dramatic progress in tumour biology and immunology in the past several years has opened new avenues for the treatment and prevention of cancer. One of the great contributions of the immunotherapeutic approaches is an increasing understanding of the immunology of cancer, which is, gradually creating conditions for the development of prophylactic anti-cancer vaccines. Efficient vaccines have been developed and employed for the prophylaxis of two frequent cancers of viral origin, namely cervical cancer and liver cancer. The new knowledge on the interactions between the immune system and the malignant tumors seems to provide means for the development of prophylactic vaccines against cancers developing due to the mutations in the proto-oncogenes converting their products into oncoproteins. According to the present estimates, these cancers form a great majority of human malignancies. Recent evidence has indicated that the immune system recognizes such mutated proteins, and that the development of cancer is due to the failure of the immune system to eliminate neoplastic cells. Followingly, it can be expected that inducing immunity against the mutated epitopes will increase the capacity of the body to deal with the initiated precancerous cells. In the present paper this hypothesis is primarily discussed in the relationship with colorectal cancer (CRC), which seems to be a well-fitting candidate for prophylactic vaccination. CRC is the third most frequent malignancy and the fourth most common cause of cancer mortality. Mutations of two proto-oncogenes, namely RAS and RAF, are involved in the majority of CRC cases and, in addition, they are shared with other human malignancies. Therefore, the strategy to be used for prophylaxis of CRC is discussed together with several other frequent human cancers, namely lung cancer, pancreatic duct cancer and melanoma. The prophylactic vaccines proposed are aimed at the reduction of the incidence of these and, to a lesser extent, some other cancers.

Exosome application in tumorigenesis: diagnosis and treatment of melanoma

Melanoma is the most aggressive of skin cancer derived from genetic mutations in the melanocytes. Current therapeutic approaches include surgical resection, chemotherapy, photodynamic therapy, immunotherapy, biochemotherapy, and targeted therapy. However, the efficiency of these strategies may be decreased due to the development of diverse resistance mechanisms. Here, it has been proven that therapeutic monoclonal antibodies (mAbs) can improve the efficiency of melanoma therapies and also, cancer vaccines are another approach for the treatment of melanoma that has already improved clinical outcomes in these patients. The use of antibodies and gene vaccines provides a new perspective in melanoma treatment. Since the tumor microenvironment is another important factor for cancer progression and metastasis, in recent times, a mechanism has been identified to provide an opportunity for melanoma cells to communicate with remote cells. This mechanism is involved by a novel molecular structure, named extracellular vesicles (EVs). Depending on the functional status of origin cells, exosomes contain various cargos and different compositions. In this review, we presented recent progress of exosome applications in the treatment of melanoma. Different aspects of exosome therapy and ongoing efforts in this field will be discussed too.

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.

A biomarker panel predicts recurrence-free survival in ulcerated primary cutaneous melanoma

BACKGROUND

Ulceration is an independent adverse prognostic factor in cutaneous malignant melanoma (CMM). There is, however, a need for additional prognostic markers to identify patients with ulcerated stage I-II CMM who have a high-risk for recurrence. The aim of this study was to examine the prognostic impact of BRAF mutation, proliferation and presence of tumour infiltrating lymphocytes (TILs) in primary ulcerated CMM.

MATERIAL AND METHODS

We have used a consecutive cohort consisting of 71 primary ulcerated CMM (T1b-T4b). BRAF mutation was detected using Cobas test and pyrosequencing. Protein expression of the proliferation marker Ki67 was analysed using immunohistochemistry. Presence of TILs was evaluated in representative hematoxylin-eosin stained formalin-fixed paraffin-embedded tumour sections.

RESULTS

Proportion of BRAF mutated alleles, proliferation and presence of TILs all had a statistically significant impact on recurrence free survival in univariate analyses (HR 2.44, 95% CI 1.23-4.84, p = 0.011; HR 2.66, 95% CI 1.32-5.35, p = 0.006 respectively HR 0.48, 95% CI 0.24-0.98, p = 0.045). A trend test found a statistically significant decrease in the proportion of recurrence by including the three favourable factors (BRAF wildtype/low proportion of BRAF mutated alleles, low proliferation and high presence of TILs) (p = 0.0004). When at least two out of three factors were present there was a statistically significant association with longer recurrence free survival in the multivariate analysis (HR 0.30, 95% CI 0.15-0.61, p = 0.001) when adjusted for Breslow thickness, an established independent prognostic marker for CMM.

CONCLUSION

Thus, this panel of markers could be an interesting novel concept for predicting the clinical outcome in patients with high-risk stage I-II ulcerated CMM.

YK-4-279 Attenuates Progression of Pre-Existing Pigmented Lesions to Nodular Melanoma in a Mouse Model

More options are needed for the effective treatment of melanoma. In a previous study, we discovered the small molecule drug YK-4-279 almost completely inhibited tumor progression in the BrafCA;Tyr-CreERT2;Ptenflox/flox transgenic mouse model. YK-4-279 had no effect on tumor initiation but blocked progression of invasive melanoma. Our current study was designed as a treatment model, where YK-4-279 was administered during pigmented lesion formation. The study design included the use of three groups: (1) a control group that received only DMSO without a drug (MOCK), (2) mice following our prior studies with YK-4-279 administered at the time of tumor induction (YK-4-279), and (3) mice treated during tumor initiation (YK-4-279 delay). While the MOCK mice had progression of tumors, both YK-4-279 and YK-4-279 delay groups had a significant block or delay of progression. The majority of mice in the YK-4-279 groups had a block of progression, while the YK-4-279 delay group had either a partial block (60% in male mice or 29% in females) or a delay in disease progression in females (28 days in controls to 50 days in YK-4-279 delay group). Here, we demonstrate that YK-4-279 has a significant impact on blocking or delaying tumor progression in a pre-clinical treatment model of melanoma.

BRAF and MEK Inhibitors Affect Dendritic-Cell Maturation and T-Cell Stimulation

BRAF and MEK inhibitor (BRAFi/MEKi) combinations are currently the standard treatment for patients with BRAF^V600 mutant metastatic melanoma. Since the RAS/RAF/MEK/ERK-pathway is crucial for the function of different immune cells, we postulated an effect on their function and thus interference with anti-tumor immunity. Therefore, we examined the influence of BRAFi/MEKi, either as single agent or in combination, on the maturation of monocyte-derived dendritic cells (moDCs) and their interaction with T cells. DCs matured in the presence of vemurafenib or vemurafenib/cobimetinib altered their cytokine secretion and surface marker expression profile. Upon the antigen-specific stimulation of CD8⁺ and CD4⁺ T cells with these DCs or with T2.A1 cells in the presence of BRAFi/MEKi, we detected a lower expression of activation markers on and a lower cytokine secretion by these T cells. However, treatment with any of the inhibitors alone or in combination did not change the avidity of CD8⁺ T cells in peptide titration assays with T2.A1 cells. T-helper cell/DC interaction is a bi-directional process that normally results in DC activation. Vemurafenib and vemurafenib/cobimetinib completely abolished the helper T-cell-mediated upregulation of CD70, CD80, and CD86 but not CD25 on the DCs. The combination of dabrafenib/trametinib affected DC maturation and activation as well as T-cell activation less than combined vemurafenib/cobimetinib did. Hence, for a potential combination with immunotherapy, our data indicate the superiority of dabrafenib/trametinib treatment.

The spliceosome pathway activity correlates with reduced anti-tumor immunity and immunotherapy response, and unfavorable clinical outcomes in pan-cancer

Alterations in the spliceosome pathway (SP) have been associated with diverse human cancers. In this study, we explored associations of the SP activity with various clinical features, anti-tumor immune signatures, tumor immunity-related genomic and molecular features, and the response to immunotherapies and targeted therapies in 29 cancer types from The Cancer Genome Atlas (TCGA) database. We showed that the SP activity was an oncogenic signature, as evidenced by its hyperactivation in cancer and invasive cancer subtypes and correlations with unfavorable clinical outcomes and anti-tumor immunosuppression in various cancers. The SP activity showed positive correlations with tumor mutation burden (TMB) and aneuploidy in diverse cancers, suggesting its association with genomic instability. However, the negative association between the SP activity and anti-tumor immune response was independent of its associations with aneuploidy and TMB. Furthermore, we supported that the SP activity had a negative correlation with immunotherapy response in four cancer cohorts treated by immune checkpoint inhibitors. Moreover, elevated SP activity is correlated with increased drug sensitivity for a broad spectrum of anti-tumor targeted therapies. In conclusion, the SP activity is a negative biomarker for anti-tumor immune response, prognosis, and the response to immunotherapeutic and targeted drugs in pan-cancer.

Vemurafenib Drives Epithelial-to-Mesenchymal Transition Gene Expression in BRAF Inhibitor‒Resistant BRAFV600E/NRASQ61K Melanoma Enhancing Tumor Growth and Metastasis in a Bioluminescent Murine Model

BRAF inhibitor (BRAFi) resistance compromises long-term survivorship of patients with malignant melanoma, and mutant NRAS is a major mediator of BRAFi resistance. In this study, employing phenotypic and transcriptomic analysis of isogenic melanoma cells that differ only by NRAS mutational status (BRAFi-sensitive A375-BRAF^V600E/NRAS^Q61 vs. BRAFi-resistant A375-BRAF^V600E/NRAS^Q61K), we show that BRAFi (vemurafenib) treatment selectively targets BRAF^V600E/NRAS^Q61K cells upregulating epithelial-to-mesenchymal transition (EMT) gene expression, paradoxically promoting invasiveness and metastasis in vitro and in vivo. First, NanoString nCounter transcriptomic analysis identified the upregulation of specific gene expression networks (EMT and EMT to metastasis) as a function of NRAS^Q61K status. Strikingly, BRAFi treatment further exacerbated the upregulation of genes promoting EMT in BRAF^V600E/NRAS^Q61K cells (with opposing downregulation of EMT-driver genes in the BRAF^V600E/NRAS^Q61 genotype) as detected by EMT-focused RT² Profiler qPCR array analysis. In BRAF^V600E/NRAS^Q61K cells, BRAFi treatment enhanced proliferation and invasiveness, together with activation of phosphorylated protein kinase B (Ser473), with opposing phenotypic effects observable in BRAF^V600E/NRAS^Q61 cells displaying downregulation of phosphorylated protein kinase B and phosphorylated extracellular signal-regulated kinase 1/2. In a SCID mouse bioluminescent melanoma metastasis model, BRAFi treatment enhanced lung tumor burden imposed by BRAF^V600E/NRAS^Q61K cells while blocking BRAF^V600E/NRAS^Q61 metastasis. These preclinical data document the BRAFi-driven enhancement of tumorigenesis and metastasis in BRAFi-resistant human BRAF^V600E/NRAS^Q61K melanoma, a finding with potential clinical implications for patients with NRAS-driven BRAFi-resistant tumors receiving BRAFi treatment.

Definition of Biologically Distinct Groups of Conjunctival Melanomas According to Etiological Factors and Implications for Precision Medicine

Conjunctival melanoma (ConjMel) is a potentially deadly ocular melanoma, originating from partially sunlight-exposed mucosa. We explored the mutational landscape of ConjMel and studied the correlation with etiological factors. We collected 47 primary ConjMel samples and performed next-generation sequencing of 400 genes. Hotspot mutations in BRAF, NRAS, HRAS, and KIT were observed in 16 (34%), 5 (11%), 2, and 2 cases, respectively. Patients with BRAF and CDKN2A-mutated ConjMel tended to be younger while the NF1-mutated one tended to be older. The eight tumors arising from nevi were enriched in CTNNB1 mutations (63% vs. 8%; Fisher's exact p-test = 0.001) compared to non-nevi ConjMel and five were devoid of BRAF, RAS, NF1, or KIT mutations, suggesting a specific oncogenic process in these tumors. The two KIT-mutated cases carried SF3B1 mutations and were located on sun-protected mucosa, a genotype shared with genital and anorectal mucosal melanomas. Targetable mutations were observed in ERBB2, IDH1, MET, and MAP2K1 (one occurrence each). Mutational landscape of ConjMel characterizes distinct molecular subtypes with oncogenic drivers common with mucosal and skin melanomas. CTNNB1 mutations were associated with nevus-derived ConjMel. Concomitant KIT/SF3B1 mutations in sun-protected cases suggest a common tumorigenic process with genital and anorectal mucosal melanomas.

Artemisinin inhibits NRas palmitoylation by targeting the protein acyltransferase ZDHHC6

Protein S-palmitoylation is a post-translational modification that plays a crucial role in cancer cells by regulating the function and localization of oncoproteins and tumor suppressor proteins. Here, we identify artemisinin (ART), a clinically approved antimalarial endoperoxide natural product with promising anticancer activities, as an inhibitor of the ER-residing palmitoyl transferase ZDHHC6 in cancer cells using a chemoproteomic approach. We show that ART covalently binds and inhibits ZDHHC6 to reduce palmitoylation of the oncogenic protein NRas, disrupt NRas subcellular localization, and attenuate the downstream pro-proliferative signaling cascades. Our study identifies artemisinin as a non-lipid-based palmitoylation inhibitor targeting a specific palmitoyl acyltransferase and provides valuable mechanistic insights into the anticancer activity of artemisinins that are currently being studied in human clinical trials for different cancers.