Novel Drugs and Combination Therapies for the Treatment of Metastatic Melanoma

Unlocking melanoma Suppression: Insights from Plasma-Induced potent miRNAs through PI3K-AKT-ZEB1 axis

INTRODUCTION

Melanoma is a rare but highly malignant form of skin cancer. Although recent targeted and immune-based therapies have improved survival rates by 10-15%, effective melanoma treatment remains challenging. Therefore, novel, combinatorial therapy options such as non-thermal atmospheric pressure plasma (NTP) are being investigated to inhibit and prevent chemoresistance. Although several studies have reported the apoptotic and inhibitory effects of reactive oxygen species produced by NTP in the context of melanoma, the intricate molecular network that determines the role of microRNAs (miRNAs) in regulating NTP-mediated cell death remains unexplored.

OBJECTIVES

This study aimed to explore the molecular mechanisms and miRNA networks regulated by NTP-induced oxidative stress in melanoma cells.

METHODS

Melanoma cells were exposed to NTP and then subjected to high-throughput miRNA sequencing to identify NTP-regulated miRNAs. Various biological processes and underlying molecular mechanisms were assessed using Alamar Blue, propidium iodide (PI) uptake, cell migration, and clonogenic assays followed by qRT-PCR and flow cytometry.

RESULTS

NTP exposure for 3 min was sufficient to modulate the expression of several miRNAs, inhibiting cell growth. Persistent NTP exposure for 5 min increased differential miRNA regulation, PI uptake, and the expression of genes involved in cell cycle arrest and death. qPCR confirmed that miR-200b-3p and miR-215-5p upregulation contributed to decreased cell viability and migration. Mechanistically, inhibiting miR-200b-3p and miR-215-5p in SK-2 cells enhancedZEB1, PI3K, and AKT expression, increasing cell proliferation and viability.

CONCLUSION

This study demonstrated that NTP exposure for 5 min results in the differential regulation of miRNAs related to the PI3K-AKT-ZEB1 axis and cell cycle dysregulation to facilitate melanoma suppression.

Unbiased High-Throughput Drug Combination Pilot Screening Identifies Synergistic Drug Combinations Effective against Patient-Derived and Drug-Resistant Melanoma Cell Lines

We describe the development, optimization, and validation of 384-well growth inhibition assays for six patient-derived melanoma cell lines (PDMCLs), three wild type (WT) for BRAF and three with V600E-BRAF mutations. We conducted a pilot drug combination (DC) high-throughput screening (HTS) of 45 pairwise 4×4 DC matrices prepared from 10 drugs in the PDMCL assays: two B-Raf inhibitors (BRAFi), a MEK inhibitor (MEKi), and a methylation agent approved for melanoma; cytotoxic topoisomerase II and DNA methyltransferase chemotherapies; and drugs targeting the base excision DNA repair enzyme APE1 (apurinic/apyrimidinic endonuclease-1/redox effector factor-1), SRC family tyrosine kinases, the heat shock protein 90 (HSP90) molecular chaperone, and histone deacetylases.Pairwise DCs between dasatinib and three drugs approved for melanoma therapy-dabrafenib, vemurafenib, or trametinib-were flagged as synergistic in PDMCLs. Exposure to fixed DC ratios of the SRC inhibitor dasatinib with the BRAFis or MEKis interacted synergistically to increase PDMCL sensitivity to growth inhibition and enhance cytotoxicity independently of PDMCL BRAF status. These DCs synergistically inhibited the growth of mouse melanoma cell lines that either were dabrafenib-sensitive or had acquired resistance to dabrafenib with cross resistance to vemurafenib, trametinib, and dasatinib. Dasatinib DCs with dabrafenib, vemurafenib, or trametinib activated apoptosis and increased cell death in melanoma cells independently of their BRAF status or their drug resistance phenotypes. These preclinical in vitro studies provide a data-driven rationale for the further investigation of DCs between dasatinib and BRAFis or MEKis as candidates for melanoma combination therapies with the potential to improve outcomes and/or prevent or delay the emergence of disease resistance.

A Phase Ib/II Study of the BRAF Inhibitor Encorafenib Plus the MEK Inhibitor Binimetinib in Patients with BRAFV600E/K -mutant Solid Tumors

PURPOSE

This open-label, dose-finding phase Ib/II study reports the safety and activity of the first combination use with BRAF inhibitor (BRAFi) encorafenib plus MEK inhibitor (MEKi) binimetinib in patients with BRAF V600E-mutant solid tumors.

PATIENTS AND METHODS

In phase I, the recommended phase 2 doses (RP2D) were established (primary objective). In phase II, the clinical activity of the combination at the RP2D was assessed (primary objective) in patients with BRAF-mutant metastatic colorectal cancer (mCRC), BRAFi-treated BRAF-mutant melanoma, and BRAFi-naïve BRAF-mutant melanoma.

RESULTS

A total of 126 patients with BRAF-mutant solid tumors were enrolled (phase I: 47 patients; phase II: 79 patients). The RP2D was encorafenib 450 mg once daily plus binimetinib 45 mg twice daily and pharmacokinetic data suggest that drug exposures of each agent were similar in combination compared with single-agent studies. In the phase II cohorts, confirmed responses were seen in two of 11 (18%) evaluable patients with mCRC, 11 of 26 (42%) evaluable patients with BRAFi-pretreated melanoma, and 28 of 42 (67%) BRAFi-naïve patients with melanoma. The most common grade 3/4 adverse event in phase II was increased alanine aminotransferase.

CONCLUSIONS

The combination of encorafenib (450 mg) plus binimetinib (45 mg) showed acceptable tolerability and encouraging activity in patients with BRAF V600-mutant tumors, which led to the dose selection for the melanoma COLUMBUS study. The safety profile of the combination was consistent with other approved BRAFi plus MEKi regimens, with several differences, including lower rates of dose-limiting pyrexia, arthralgia, and photosensitivity.

Therapy preferences in melanoma treatment-Willingness to pay and preference of quality versus length of life of patients, physicians, healthy individuals and physicians with oncological disease

Background

In recent years, monoclonal antibodies such as ipilimumab, nivolumab, and pembrolizumab have made a significant impact on the treatment of advanced melanoma. Combination of immune checkpoint inhibitors leads to improved survival and response rates of 58%‐61% as compared to monotherapy (36%‐44%). However, the price for the better response rates is also a higher frequency of severe adverse events (59%) as compared to monotherapy (17%‐21%). This study examines attitudes towards melanoma therapy options of physicians, healthy individuals, melanoma patients, and physicians with oncological disease, their willingness to pay, and preference of quality versus length of life.

Methods

After obtaining ethical approval and informed consent surveys were conducted in 111 participants divided into four groups: melanoma patients (n = 30), healthy individuals as controls (n = 30), physicians (n = 27), and physicians with oncological disease (n = 24). Statistical analyses were conducted using SPSS statistics (version 25, IBM), applying the Pearson´s chi‐squared test, Spearman correlation coefficient, Wilcoxon‐Mann‐Whitney test, and Kruskal‐Wallis test.

Results

Life prolongation is more valued by melanoma patients and physicians with oncological disease compared to healthy controls and healthy physicians. In total, 30% of melanoma patients opt for a life prolonging therapy in all cases, even if this life prolongation is only marginal. Physicians are the strongest proponents of combination immunotherapy.   

Conclusion

The valuation of the different treatment options differs in the four study groups with affected people valuing life prolongation much more. The individual value of cancer therapies is high, but differs from the societal standpoint.

C-Mannosyl Lysine for Solid Phase Assembly of Mannosylated Peptide Conjugate Cancer Vaccines

Dendritic cells (DCs) are armed with a multitude of Pattern Recognition Receptors (PRRs) to recognize pathogens and initiate pathogen-tailored T cell responses. In these responses, the maturation of DCs is key, as well as the production of cytokines that help to accomplish T cell responses. DC-SIGN is a frequently exploited PRR that can effectively be targeted with mannosylated antigens to enhance the induction of antigen-specific T cells. The natural O-mannosidic linkage is susceptible to enzymatic degradation, and its chemical sensitivity complicates the synthesis of mannosylated antigens. For this reason, (oligo)mannosides are generally introduced in a late stage of the antigen synthesis, requiring orthogonal conjugation handles for their attachment. To increase the stability of the mannosides and streamline the synthesis of mannosylated peptide antigens, we here describe the development of an acid-stable C-mannosyl lysine, which allows for the inline introduction of mannosides during solid-phase peptide synthesis (SPPS). The developed amino acid has been successfully used for the assembly of both small ligands and peptide antigen conjugates comprising an epitope of the gp100 melanoma-associated antigen and a TLR7 agonist for DC activation. The ligands showed similar internalization capacities and binding affinities as the O-mannosyl analogs. Moreover, the antigen conjugates were capable of inducing maturation, stimulating the secretion of pro-inflammatory cytokines, and providing enhanced gp100 presentation to CD8⁺ and CD4⁺ T cells, similar to their O-mannosyl counterparts. Our results demonstrate that the C-mannose lysine is a valuable building block for the generation of anticancer peptide-conjugate vaccine modalities.

ADAR1p150 regulates the biosynthesis and function of miRNA-149* in human melanoma

Melanoma is an aggressive malignant skin tumor. Study found that miR-149* was abnormally expressed in melanoma. Adenosine deaminases acting on the RNA1 (ADAR1) is an RNA editing enzyme. It can change the structure and function of miRNA. In this study, we investigate the role of ADAR1 in regulation of miRNA-149* in melanoma. Western-blot analysis was used to analyze the expression of ADAR1p150, ADAR1p110 and GSK3α at protein level. The expression of ADAR1p150, miR-149* and GSK3α at mRNA level were detected using qRT-PCR. Co-immunoprecipitation test was then performed to determine the interaction between ADAR1 and Dicer. Target verification of miRNA-149*/GSK3α was carried out using luciferase reporter assay. CCK-8 was used to detect cell proliferation. Cell apoptosis was tested using Tunel assays. The expression level of ADAR1p150 was found to be increased in human melanoma tissues, but not ADAR1p110. There was a direct interaction between ADAR1p150 and Dicer in melanoma cells. MiRNA-149* was significantly up-regulated in melanoma tissues and melanoma cells. Luciferase reporter assay suggested that GSK3α was a directly target of miR-149*. The expression level of miR-149* showed a positive correlation with ADAR1p150. At the same time, ADAR1p150 expression was negatively correlated with the expression of GSK3α. ADAR1p150 promoted proliferation of melanoma cells and inhibited cell apoptosis. ADAR1p150 can promote the biosynthesis and function of miRNA-149* in melanoma cells which makes it be considered as both a bio-marker and a therapeutic target for treatment of melanoma.

Immunotherapy-based combinations: an update

PURPOSE OF REVIEW

The advent of immunotherapy significantly improved clinical outcomes in cancer patients, although immune checkpoint blockade (ICB) still lack of efficacy in a consistent proportion of treated patients. The purpose of this article is to review the most innovative and clinically promising ICB-based combinations designed to improve the efficacy of cancer immunotherapy.

RECENT FINDINGS

First-line combinatorial treatment with ipilimumab and nivolumab has recently shown to be superior to the standard of care in a subset of metastatic nonsmall cell lung cancer (NSCLC) and renal cell carcinoma (RCC). The combination of programmed cell death protein 1 (PD-1)/PD-L1 blockade with antiangiogenics has demonstrated a consistent clinical efficacy, especially for the combination of bevacizumab and atezolizumab as first-line therapy in metastatic RCC. The sequential combination of definitive chemoradiotherapy followed by durvalumab maintenance in advanced, unresectable NSCLC became the new standard of care, while the addition of pembrolizumab to first-line chemotherapy in metastatic NSCLC significantly improves overall survival. Despite promising results for the combination of ICBs with v-raf murine sarcoma viral oncogene homolog B/MAPK/ERK kinase inhibitors or epidermal growth factor receptor inhibitors, especially in melanoma and NSCLC, safety concerns slowed down the development of such strategies.

SUMMARY

Immunotherapy-based combinations are becoming the standard of care for cancer treatment, in particularly for advanced melanoma, NSCLC and RCC.

Biomarker results from a phase II study of MEK1/2 inhibitor binimetinib (MEK162) in patients with advanced NRAS- or BRAF-mutated melanoma

BRAF and RAS are the most frequently mutated mitogen-activated protein kinase (MAPK) genes in melanoma. Binimetinib is a highly selective MAPK kinase (MEK) 1/2 inhibitor with clinical antitumor activity in NRAS- and BRAF V600-mutant melanoma. We performed a nonrandomized, open-label phase II study, where 183 metastatic melanoma patients received binimetinib 45 mg / 60 mg twice-daily (BRAF arms), or binimetinib 45 mg twice-daily (NRAS arm). Biomarker analyses were prespecified as secondary and exploratory objectives. Here we report the extent of MAPK pathway inhibition by binimetinib, genetic pathway alterations of interest, and potential predictive markers for binimetinib efficacy. Twenty-five fresh pre- and post-dose tumor sample pairs were collected for biomarker analyses, which included assessment of binimetinib on MEK/MAPK signaling by pharmacodynamic analysis of pERK and DUSP6 expression in pre- vs post-dose tumor biopsies; identification of pERK and DUSP6 expression/efficacy correlations; assessment of baseline tumor molecular status; and exploration of potential predictive biomarkers of efficacy of binimetinib. The postbaseline pERK and DUSP6 expression decreased across all arms; no association between reduced pERK or DUSP6 levels with clinical efficacy was observed. Genetic aberrations were similar to previously reported data on clinical melanoma samples. Genetic pathway alterations occurred predominantly within CDKN2A/B, PTEN, and TRRAP (BRAF-mutation) and CDKN2A/B, TP53, and NOTCH2 (NRAS-mutation). Several patients with BRAF mutations had amplification of genes on chromosome 7q; these patients tended to have shorter progression-free survival than other patients with BRAF-mutant melanoma. Further analysis of genetic alterations, including amplifications of growth factor genes, will determine utility as biomarkers for efficacy.

Role of Anti-PD-1 Antibodies in Advanced Melanoma: The Era of Immunotherapy

Advanced melanoma is an aggressive skin cancer characterized by poor survival rates and response to cytotoxic chemotherapy. Immune checkpoint inhibitors are novel agents capable of utilizing one's own immune system to bring about the tumor destruction. Nivolumab and pembrolizumab are fully humanized anti-PD-1 monoclonal antibodies that have shown significant anti-tumor activity in a variety of cancers including melanoma and have significantly improved the survival outcomes in patients with advanced melanoma. In this updated review article, we will discuss the outcomes of various clinical trials evaluating the efficacy and safety of these agents. We will also briefly discuss their mechanism of action and adverse effects.

Cutaneous toxicities of new treatments for melanoma

New drugs against advanced melanoma have emerged during last decade. Target therapy and immunotherapy have changed the management of patients with metastatic disease. Along with its generalized use, drug toxicities have appeared and the skin is the target organ of a significant part of them. This revision summarizes the most common side effects and consensus management to improve the compliance of therapies and patients' quality of life. Among the BRAF inhibitors, main cutaneous side effects are photosensitivity, plantar hyperkeratosis, and the appearance of verrucal keratosis or squamous cell carcinoma. Special attention must be paid to the development of new primary melanomas or changes on nevi during BRAF inhibitor therapy. The most common cutaneous side effects of immunotherapy are rash, pruritus, and vitiligo. It remains controversial the possible role of these toxicities as markers of response to therapy.

Gefitinib or lapatinib with foretinib synergistically induce a cytotoxic effect in melanoma cell lines

Melanoma is an aggressive cancer type with a high mortality rate and an elevated resistance to conventional treatment. Recently, promising new tools for anti-melanoma targeted therapy have emerged including inhibitors directed against frequently overexpressed receptors of growth factors implicated in the progression of this cancer. The ineffectiveness of single-targeted therapy prompted us to study the efficacy of treatment with a combination of foretinib, a MET (hepatocyte growth factor receptor) inhibitor, and gefitinib or lapatinib, EGFR (epidermal growth factor receptor) inhibitors. We observed a synergistic cytotoxic effect for the combination of foretinib and lapatinib on the viability and proliferation of the examined melanoma cell lines. This combination of inhibitors significantly decreased Akt and Erk phosphorylation, while the drugs used independently were insufficient. Additionally, after treatment with pairs of inhibitors, cells became larger, with more pronounced stress fibers and abnormally shaped nuclei. We also noticed the appearance of polyploid cells and massive enrichment in the G2/M phase. Therefore, combination treatment was much more effective against melanoma cells than a single-targeted approach. Based on our results, we conclude that both EGFR and MET receptors might be effective targets in melanoma therapy. However, variation in their levels in patients should be taken into consideration.

Copper Silicate Hollow Microspheres-Incorporated Scaffolds for Chemo-Photothermal Therapy of Melanoma and Tissue Healing

The treatment of melanoma requires complete removal of tumor cells and simultaneous tissue regeneration of tumor-initiated cutaneous defects. Herein, copper silicate hollow microspheres (CSO HMSs)-incorporated bioactive scaffolds were designed for chemo-photothermal therapy of skin cancers and regeneration of skin tissue. CSO HMSs were synthesized with interior hollow and external nanoneedle microstructure, showing excellent drug-loading capacity and photothermal effects. With incorporation of drug-loaded CSO HMSs into the electrospun scaffolds, the composite scaffolds exhibited excellent photothermal effects and controlled NIR-triggered drug release, leading to distinctly synergistic chemo-photothermal therapy of skin cancer both in vitro and in vivo. Furthermore, such CSO HMSs-incorporated scaffolds could promote proliferation and attachment of normal skin cells and accelerate skin tissue healing in tumor-bearing and diabetic mice. Taken together, CSO HMSs-incorporated scaffolds may be used for complete eradication of the remaining tumor cells after surgery and simultaneous tissue healing, which offers an effective strategy for therapy and regeneration of tumor-initiated tissue defects.

Validation of the Graded Prognostic Assessment for Melanoma Using Molecular Markers (Melanoma-molGPA)

Background

It has been suggested to replace the diagnosis-specific graded prognostic assessment (DS-GPA, based on performance status and number of brain metastases) for patients with primary malignant melanoma with the new Melanoma-molGPA. The latter is a more complex assessment, which also includes BRAF mutation status, age and extracranial metastases. To test the performance of the Melanoma-molGPA, we performed a validation study of this new survival prediction tool.

Methods

A retrospective analysis of patients treated at two different academic institutions was performed. The four-tiered Melanoma-molGPA was calculated as suggested in the original study.

Results

Median overall survival was 5.4 months (95% confidence interval: 3.1 - 7.7 months). Median survival in the four prognostic classes was 2.1, 7.8, 11.8, and 18.0 months, respectively. The 1-year survival rates were 3%, 25%, 43%, and 80%, respectively. The difference between the Kaplan-Meier curves was significant (P = 0.0001, log-rank test).

Conclusions

The present survival outcomes support the use of the Melanoma-molGPA. However, survival was better in each of the four groups in the original study. Possible reasons include lead-time bias and different treatment policies.

MicroRNA-195 acts as an anti-proliferative miRNA in human melanoma cells by targeting Prohibitin 1

Background

Melanoma is the most lethal type of skin cancer. Since chemoresistance is a significant barrier, identification of regulators affecting chemosensitivity is necessary in order to create new forms of intervention. Prohibitin 1 (PHB1) can act as anti-apoptotic or tumor suppressor molecule, depending on its subcellular localization. Our recent data shown that accumulation of PHB1 protects melanoma cells from chemotherapy-induced cell death. Lacking of post-transcriptional regulation of PHB1 could explain this accumulation. Interestingly, most of melanoma patients have down-regulation of microRNA-195. Here, we investigate the role of miR-195, its impact on PHB1 expression, and on chemosensitivity in melanoma cells.

Methods

TCGA-RNAseq data obtained from 341 melanoma patient samples as well as a panel of melanoma cell lines were used in an expression correlation analysis between PHB1 and predicted miRNAs. miR-195 impact on PHB1 mRNA and protein levels and relevance of this regulation were investigated in UACC-62 and SK-MEL-5 melanoma lines by RT-qPCR and western blot, luciferase reporter and genetic rescue experiments. Cell proliferation, cell-cycle analysis and caspase 3/7 assay were performed to investigate the potential action of miR-195 as chemosensitizer in melanoma cells treated with cisplatin and temozolomide.

Results

Analysis of the TCGA-RNAseq revealed a significant negative correlation (Pearson) between miR-195 and PHB1 expression. Moreover, RT-qPCR data showed that miR-195 is down-regulated while PHB1 is up-regulated in a collection of melanoma cells. We demonstrated that miR-195 regulates PHB1 directly by RT-qPCR and western blot in melanoma cells and luciferase assays. To establish PHB1 as a relevant target of miR-195, we conducted rescue experiments in which we showed that PHB1 transgenic expression could antagonize the suppressive effect miR-195 on the proliferation of melanoma cells. Finally, transfection experiments combined with drug treatments performed in the UACC-62 and SK-MEL-5 melanoma cells corroborated miR-195 as potential anti-proliferative agent, with potential impact in sensitization of melanoma cell death.

Conclusions

This study support the role of miR-195 as anti-proliferative miRNA via targeting of PHB1 in melanoma cells.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3721-7) contains supplementary material, which is available to authorized users.

A novel stilbene-like compound that inhibits melanoma growth by regulating melanocyte differentiation and proliferation

Melanoma is the most aggressive form of skin cancer. Current challenges to melanoma therapy include the adverse effects from immunobiologics, resistance to drugs targeting the MAPK pathway, intricate interaction of many signal pathways, and cancer heterogeneity. Thus combinational therapy with drugs targeting multiple signaling pathways becomes a new promising therapy. Here, we report a family of stilbene-like compounds called A11 that can inhibit melanoma growth in both melanoma-forming zebrafish embryos and mouse melanoma cells. The growth inhibition by A11 is a result of mitosis reduction but not apoptosis enhancement. Meanwhile, A11 activates both MAPK and Akt signaling pathways. Many A11-treated mouse melanoma cells exhibit morphological changes and resemble normal melanocytes. Furthermore, we found that A11 causes down-regulation of melanocyte differentiation genes, including Pax3 and MITF. Together, our results suggest that A11 could be a new melanoma therapeutic agent by inhibiting melanocyte differentiation and proliferation.

Inhibitors of Cytotoxic T Lymphocyte Antigen 4 and Programmed Death 1/Programmed Death 1 Ligand for Metastatic Melanoma, Dual Versus Monotherapy-Summary of Advances and Future Directions for Studying These Drugs

Immense progress in the field of cancer immunotherapy has garnered several novel and successful treatments for metastatic melanoma. Beginning with therapies targeting cytotoxic T lymphocyte antigen 4 (CTLA-4), objective response rates, overall survival, and long-term survival were significantly increased when compared with glycoprotein 100 vaccine therapies. Expanding the breadth of therapies aimed to "release the breaks" on the active immune system, anti-programmed death 1 (PD-1) and anti-programmed death 1 ligand (PD-L1) therapies further improved overall survival, progression-free survival, and objective tumor response while exhibiting more favorable safety profiles compared with ipilimumab and to chemotherapy agents. Given the power of these agents as monotherapies, a combination approach sought to combine the anti-CTLA agent ipilimumab and anti-PD-1 agent, nivolumab, to form a double-pronged attack and target several mechanisms within the active immune system. Given the promise in elevated response rates and progression-free survival, the future appears promising along the immunotherapy front. Continuing the push for progress, biomarkers to uncover the profile of responders to the various therapies will become vital in the treatment of metastatic melanoma patients. Here, we highlight the advances of CTLA-4 and PD-1/PD-L1 inhibitors in the metastatic melanoma setting and discuss future directions for uncovering the full potential of these therapies.

Immunoregulatory protein B7-H3 promotes growth and decreases sensitivity to therapy in metastatic melanoma cells

B7-H3 (CD276) belongs to the B7 family of immunoregulatory proteins and has been implicated in cancer progression and metastasis. In this study, we found that metastatic melanoma cells with knockdown expression of B7-H3 showed modest decrease in proliferation and glycolytic capacity and were more sensitive to dacarbazine (DTIC) chemotherapy and small-molecule inhibitors targeting MAP kinase (MAPK) and AKT/mTOR pathways: vemurafenib (PLX4032; BRAF inhibitor), binimetinib (MEK-162; MEK inhibitor), everolimus (RAD001; mTOR inhibitor), and triciribidine (API-2; AKT inhibitor). Similar effects were observed in melanoma cells in the presence of an inhibitory B7-H3 monoclonal antibody, while the opposite was seen in B7-H3-overexpressing cells. Further, combining B7-H3 inhibition with small-molecule inhibitors resulted in significantly increased antiproliferative effect in melanoma cells, as well as in BRAF^V600E mutated cell lines derived from patient biopsies. Our findings indicate that targeting B7-H3 may be a novel alternative to improve current therapy of metastatic melanoma.

Sphingosine metabolism as a therapeutic target in cutaneous melanoma

Melanoma is by far the most aggressive type of skin cancer with a poor prognosis in its advanced stages. Understanding the mechanisms involved in melanoma pathogenesis, response, and resistance to treatment has gained a lot of attention worldwide. Recently, the role of sphingolipid metabolism has been studied in cutaneous melanoma. Sphingolipids are bioactive lipid effector molecules involved in the regulation of various cellular signaling pathways such as inflammation, cancer cell proliferation, death, senescence, and metastasis. Recent studies suggest that sphingolipid metabolism impacts melanoma pathogenesis and is a potential therapeutic target. This review focuses on defining the role of sphingolipid metabolism in melanoma carcinogenesis, discussing sphingolipid-based therapeutic approaches, and highlighting the areas that require more extensive research.

Pediatric Cerebellar Tumors: Emerging Imaging Techniques and Advances in Understanding of Genetic Features

Cerebellar tumors are the most common group of solid tumors in children. MR imaging provides an important role in characterization of these lesions, surgical planning, and postsurgical surveillance. Preoperative imaging can help predict the histologic subtype of tumors, which can provide guidance for surgical planning. Beyond histology, pediatric brain tumors are undergoing new classification schemes based on genetic features. Intraoperative MR imaging has emerged as an important tool in the surgical management of pediatric brain tumors. Effective understanding of the imaging features of pediatric cerebellar tumors can benefit communication with neurosurgeons and neuro-oncologists and can improve patient management.

Adapt, Recycle, and Move on: Proteostasis and Trafficking Mechanisms in Melanoma

Melanoma has emerged as a paradigm of a highly aggressive and plastic cancer, capable to co-opt the tumor stroma in order to adapt to the hostile microenvironment, suppress immunosurveillance mechanisms, and disseminate. In particular, oncogene- and aneuploidy-driven dysregulations of proteostasis in melanoma cells impose a rewiring of central proteostatic processes, such as the heat shock and unfolded protein responses, autophagy, and the endo-lysosomal system, to avoid proteotoxicity. Research over the past decade has indicated that alterations in key nodes of these proteostasis pathways act in conjunction with crucial oncogenic drivers to increase intrinsic adaptations of melanoma cells against proteotoxic stress, modulate the high metabolic demand of these cancer cells and the interface with other stromal cells, through the heightened release of soluble factors or exosomes. Here, we overview and discuss how key proteostasis pathways and vesicular trafficking mechanisms are turned into vital conduits of melanoma progression, by supporting cancer cell's adaptation to the microenvironment, limiting or modulating the ability to respond to therapy and fueling melanoma dissemination.

Usefulness of serum 5-S-cysteinyl-dopa as a biomarker for predicting prognosis and detecting relapse in patients with advanced stage malignant melanoma

With the recent development of novel molecular targeted drugs for advanced stage malignant melanoma (MM), including RAF and mitogen-activated protein kinase kinase inhibitors and immune checkpoint blockers, the early detection of relapse is important for managing patients with MM. In this study, we retrospectively analyzed two conventional serum biomarkers, 5-S-cysteinyl-dopa and lactate dehydrogenase, in patients with MM (n = 140) who were treated at a single Japanese institute from June 2007 to June 2015. At the initial hospital visit, serum 5-S-cysteinyl-dopa levels were significantly increased in patients with stages III (n = 38) and IV (n = 20) MM compared with patients with stages 0-II (n = 62) MM. In addition, in patients with stages III and IV MM, serum 5-S-cysteinyl-dopa levels of more than 15.0 nmol/L at initial hospital visit correlated with a poor prognosis. In 11 of 14 patients whose disease progressed during follow up (mostly from stages III-IV), serum 5-S-cysteinyl-dopa levels exceeded the normal limit of 10.0 nmol/L during the clinical detection of distant metastases. These results indicate the usefulness of measuring serum 5-S-cysteinyl-dopa levels at initial hospital visit and during follow up for early and effective therapeutic interventions using newly developed molecular targeted drugs.

Programmed death-ligand 1 expression in rectal cancer

Background

Colorectal cancer (CRC) is the fourth most common cause of death worldwide. Approximately 30 % of all CRC occurs in the rectum. Improvements in survival rates were achieved thanks to multimodal therapy, combining surgery and chemoradiation. Nevertheless, the prognosis of patients suffering from rectal cancer (RC) remains poor. Programmed cell death protein 1 (PD-1) and its ligand programmed death ligand 1 (PD-L1) regulate tumor immune response. The aim of this study was to analyze the expression of PD-L1 in RC pre- and post-neoadjuvant therapy and evaluate PD-L1 as a biomarker and potential target for therapy.

Methods

In all, 29 patients with RC treated at the Medical University Vienna who received preoperative chemoradiation were retrospectively enrolled in this study. Expression of PD-L1 was investigated by immunohistochemistry with two different anti-PD-L1 antibodies.

Results

No PD-L1 expression on cancer cells could be observed in all 29 cases in the specimens before chemoradiation as well as in the surgical specimens after neoadjuvant therapy. In one of the two staining methods performed, five (17.24 %) post-chemoradiation cases showed faint lymphohistiocytic staining.

Conclusion

No expression of PD-L1 in RC cells before and after chemoradiation was found in our collective of 29 patients. Further investigations to evaluate the role of PD-L1 as a potential therapeutic target in RC are urgently needed.

Advances in immunotherapy for melanoma management

Melanoma remains a leading cause of death among young adults. Evidence that melanoma tumor cells are highly immunogenic and a better understanding of T-cell immune checkpoints have changed the therapeutic approach to advanced melanoma. Instead of targeting the tumor directly, immunotherapy targets and activates the immune response using checkpoint inhibitors, monoclonal antibodies, vaccines, and adoptive T cell therapy. This review focuses on the immune signaling and biological mechanisms of action of recent immune-based melanoma therapies as well as their clinical benefits.

Primary cerebral malignant melanoma in insular region with extracranial metastasis: case report and review literature

BACKGROUND

Primary brain melanomas are very infrequent and metastasis outside central nervous system very uncommon. There are some cases in the literature about primary melanoma in the temporal lobe; nevertheless, the insular location has never been described.

CASE PRESENTATION

The patient presented as left insular intraparenchymal hematoma with multiple bleedings. Complementary tests did not show any tumoral nor vascular pattern in relation with these bleedings. A complete surgical resection was performed, and the diagnosis of malignant melanoma, with BRAF mutation, was obtained after histology exam. Extension studies were negative for skin or mucous melanoma. 18F-FDG PET/CT was performed and a metastatic lymph node was found. The diagnosis was primary brain melanoma with extracerebral metastasis. Dabrafenib 150 mg/12 h was the only chemotherapy during 5 months. After that, Trametinib 2 mg/24 h was added to the treatment. Eighteen months after surgery, the patient is independent, with stable situation, and without new metastasis.

CONCLUSIONS

Although malignant melanomas have poor prognosis, total surgical resection and new therapies are increasing the overall survival and improving quality of life. In a patient with suspected brain melanoma, in spite of having extracerebral metastasis, aggressive treatment may be considered.

Combined Therapy with Dabrafenib and Trametinib in BRAF-Mutated Metastatic Melanoma in a Real-Life Setting: The INT Milan Experience

Purpose

Combination therapy with dabrafenib and trametinib is safer and more effective than BRAF inhibitor-based monotherapy for metastatic melanoma.

Methods

We retrospectively analyzed BRAF-mutated metastatic melanoma patients treated at our institution with daily oral dabrafenib 300 mg and trametinib 2 mg from November 2013 to April 2016. This clinical record included both untreated and previously treated stage IV melanomas. Physical examination and laboratory examinations were performed monthly and disease re-evaluations were performed every 3 months.

Results

A total of 48 patients (24 male, 24 female) with BRAF-mutated metastatic melanoma received dabrafenib and trametinib; median age was 48 years (range 23-75). Median follow-up was 362.5 days (range 72-879). Best overall response rate consisted of 6.2% (3 patients) complete response, 64.6% (31) partial response, and 25% ( 12 ) stable disease; median time to best response was 11 weeks (range 5.7-125.5). Progression of disease was seen in 19 patients (39.6%), with median time to progression (TTP) of 26 weeks (range 8-54). A total of 15 patients (31.2%) died due to progression of disease. Median progression-free survival and median overall survival were not reached. To date, 30 patients (62.5%) are still under treatment. A total of 27 (56.2%) patients had at least one adverse event (AE); grade 3-4 AEs were seen in 4 cases (8.3%). The main toxicities were fever (25%), skin rash (14.6%), arthralgias (10.4%), and aspartate aminotransferase/alanine aminotransferase increase (8.3%). Treatment dose was reduced in 7 subjects (14.6%), with only one case of discontinuation due to AE.

Conclusions

Our data, using combined targeted therapy, are in line with the scientific literature in terms of both safety and effectiveness in a real-life setting.

Pediatric Cerebellar Tumors: Emerging Imaging Techniques and Advances in Understanding of Genetic Features

Cerebellar tumors are the most common group of solid tumors in children. MR imaging provides an important role in characterization of these lesions, surgical planning, and postsurgical surveillance. Preoperative imaging can help predict the histologic subtype of tumors, which can provide guidance for surgical planning. Beyond histology, pediatric brain tumors are undergoing new classification schemes based on genetic features. Intraoperative MR imaging has emerged as an important tool in the surgical management of pediatric brain tumors. Effective understanding of the imaging features of pediatric cerebellar tumors can benefit communication with neurosurgeons and neuro-oncologists and can improve patient management.

The discovery of vemurafenib for the treatment of BRAF-mutated metastatic melanoma

INTRODUCTION

In the era of precision medicine and sophisticated modern genetics, the discovery of the BRAF(V600) inhibitor, vemurafenib, quickly became the model for targeted therapy in melanomas. As early as 2002, the majority of metastatic melanomas were described to harbor the BRAF(V600) mutation, setting the stage for an explosion of interest for targeting this protein as a novel therapeutic strategy. The highly selective BRAF(V600) inhibitor, vemurafenib, was identified initially through a large-scale drug screen.

AREAS COVERED

Here we examine vemurafenib's journey from discovery to clinical use in metastatic melanoma. Topics covered include preclinical data, single agent Phase 1,2 and 3 clinical trials, resistance issues and mechanisms, adverse effects including the development of squamous cell cancers, and combination trials.

EXPERT OPINION

Due to its tolerance, low toxicity profile, rapid tumor response, and improved outcomes in melanoma patients with BRAF(V600) mutations, vemurafenib was advanced rapidly through clinical trials to receive FDA approval in 2011. While its efficacy is well documented, durability has become an issue for most patients who experience therapeutic resistance in approximately 6-8 months. In addition, a concerning toxicity observed in patients taking the drug include development of localized cutaneous squamous cell carcinomas (SCCs). It is hypothesized that drug resistance and SCC development result from a similar paradoxical activation of protein signaling pathways, specifically MAPK. Identification of these mechanisms has led to additional treatment strategies involving new combination therapies.

Computational Modeling of PI3K/AKT and MAPK Signaling Pathways in Melanoma Cancer

BACKGROUND

Malignant melanoma is an aggressive tumor of the skin and seems to be resistant to current therapeutic approaches. Melanocytic transformation is thought to occur by sequential accumulation of genetic and molecular alterations able to activate the Ras/Raf/MEK/ERK (MAPK) and/or the PI3K/AKT (AKT) signalling pathways. Specifically, mutations of B-RAF activate MAPK pathway resulting in cell cycle progression and apoptosis prevention. According to these findings, MAPK and AKT pathways may represent promising therapeutic targets for an otherwise devastating disease.

RESULT

Here we show a computational model able to simulate the main biochemical and metabolic interactions in the PI3K/AKT and MAPK pathways potentially involved in melanoma development. Overall, this computational approach may accelerate the drug discovery process and encourages the identification of novel pathway activators with consequent development of novel antioncogenic compounds to overcome tumor cell resistance to conventional therapeutic agents. The source code of the various versions of the model are available as S1 Archive.