BRAF Wild-type Melanoma Research Articles

The Investigation of Hsp90C-Terminal Inhibitors Containing Amide Bioisosteres.

Heat Shock Protein 90 (Hsp90) is responsible for the proper folding and maturation of ~400 client protein substrates, many of which are directly associated with the ten hallmarks of cancer. Hsp90 is a great target for cancer therapy including melanoma, since Hsp90 inhibition can disrupt multiple oncogenic pathways simultaneously. In this study, we report the synthesis and anti-proliferative activity manifested by a series of Hsp90 C-terminal inhibitors against mutant BRAF and wild-type BRAF melanoma cells. Furthermore, we explored structure-activity relationships (SAR) for the amide moiety of 6 (B1), a novel Hsp90C-terminal inhibitor via introduction of amide bioisosteres. Compound 6 displayed an IC50 of 1.01 μM, 0.782 μM, 0.607 μM and 1.413 μM against SKMel173, SKMel103, SKMel19 and A375 cells, respectively.

Factors associated with response to talimogene laherparepvec in the treatment of advanced melanoma

Talimogene laherparepvec (T-VEC) is currently the only United States Food and Drug Administration-approved intralesional therapy for advanced melanoma. Recent studies have assessed the integration of T-VEC with systemic immunotherapy, though the response remains variable. Therefore, we sought to identify factors associated with the response to T-VEC by conducting a retrospective, single-center analysis involving melanoma patients treated with T-VEC. In the present study, we recorded demographic and clinicopathological data, details of T-VEC treatments, prior and concurrent treatments, and clinical outcomes. The primary endpoint was the in-field overall response rate (ORR: complete + partial). Secondary endpoints included complete in-field response, defined as complete resolution of disease or a negative biopsy; disease failure-free survival (DFFS), defined from the initiation of treatment as the time to progression in patients who did not experience a disease-free interval and time to recurrence in those who did; and overall survival (OS). We used two-sample t-tests for continuous variables and Fisher’s exact test for categorical variables. DFFS and OS were further analyzed using the Kaplan–Meier method and log-rank tests for selected variables. Among the 18 patients who met the inclusion criteria, an in-field response was observed in 14 (78%) patients. Low disease burden (<5 lesions or a total diameter <5 cm) was associated with a higher in-field ORR compared to high-burden disease (100% vs. 43%, P = 0.01). There was a trend toward decreased in-field ORR for patients with >2 prior lines of systemic therapy (P = 0.18). With a median follow-up of 386 days, DFFS was associated with BRAF wild-type melanoma (P = 0.04), an in-field ORR (P = 0.007), and a measurable bystander response (P = 0.01). Two or more prior lines of immunotherapy were associated with poorer survival (P = 0.006) and worse DFFS (P = 0.02). In conclusion, despite a low sample size, we identified covariates associated with in-field ORR, DFFS, and OS, warranting further study.

Real-world outcomes of combined lenvatinib and anti-PD-1 in advanced melanoma: Lenvamel, a multicenter retrospective study of the French Group of Skin Cancers.

9546 Background: Treatment options for patients (pts) with advanced melanoma who experience resistance to immunotherapy (ICI) +- targeted therapy are lacking. Studies suggest the anti-tumour activity of combined pembrolizumab and lenvatinib in pts progressing on ICI. We report the clinical outcomes of combined lenvatinib and anti-PD-1 in this population. Methods: This French multicenter real-world study was conducted from 09/2020 to 07/2023. The primary endpoint was objective response rate (ORR) according to the RECIST criteria (v.1.1). Secondary endpoints were treatment-related adverse events (TRAEs), progression-free survival (PFS), overall survival (OS) and duration of response (DOR). Results: Of the 67 pts included (median age, 69 years; median follow-up, 5.0 months), 85% had stage IV M1c or M1d disease. Baseline characteristics are presented (Table). Overall ORR was 28.4% (95%CI, 18–41%), including 3 complete (4.5%) and 16 partial (23.9%) responses. ORR was 71.4% (95%CI, 29–96%) for mucosal melanoma, 32,8% (95%CI, 21–46%) for pts pre-treated with anti-PD-1 + anti-CTLA-4, and 31,5% (95%CI, 20–46%) for BRAF wild-type melanoma. Median DOR was 3.1 (IQR, 1.3–4.3) months. Median PFS and OS were 3.1 (95% CI, 2.5–3.7) and 9.8 (95% CI, 5.6–13.9) months respectively. Grade 3–4 TRAEs occurred in 16 pts (24%, no grade 5); common TRAEs were fatigue (43.3%), nausea/vomiting (26.8%), diarrhea (20.9%), and hypertension (20.9%). Conclusions: Our study demonstrates an interesting response rate and acceptable safety profile of this combination, with manageable toxicities, in an immuno-refractory population with poor prognostic factors. Pts pre-treated with anti-PD-1+ anti-CTLA-4, and those with BRAF wild-type melanoma seemed to benefit more from this strategy. Our study also provides promising data (considering the small sample) for pts with mucosal melanoma. Our data support this treatment option for refractory melanoma, though not yet approved by the health authorities, and highlight the need for new strategies. [Table: see text]

Contemporary management of patients with advanced melanoma: Utility of an online interactive decision support tool to assess concordance of healthcare professional treatment patterns with expert recommendations.

e13548 Background: The treatment landscape for patients with melanoma continues to evolve with approvals of novel therapeutic agents for advanced disease and new indications for therapy in earlier-stage disease. Using an online decision support tool, we compared practice patterns and treatment recommendations between community healthcare professionals (HCPs) and key opinion leaders (KOLs). Methods: The online decision support tool was developed with input from 5 KOLs who provided treatment recommendations for 151 hypothetical patients. Case scenarios covered a spectrum of stages (III, IV), central nervous system (CNS) metastases, BRAF mutation status, and treatment histories. HCPs entered specific patient criteria into the tool to define a case and their intended therapy choice and the tool then showed 5 KOL recommendations for that patient case. An analysis of KOL recommendations and HCP-selected therapy was performed. Results: Between August 2023 and January 2024, 156 patient cases were entered by 100 HCPs. HCP and KOL recommendations were concordant in 51% (80/156) of cases. The highest level of discord among HCPs and KOLs was 72% for patients with completely resected stage IIIA melanoma and no positive lymph nodes having a metastatic focus ≥1mm (n = 25) (Table). A lower level of discordance (31%, n = 35) was observed in therapy selection for patients with stage IIIA melanoma and ≥1 positive lymph node. For first-line therapy in patients with unresectable stage III or IV BRAF wild-type melanoma (n = 16), discordance was 50% between HCPs and KOLs. The level of discordance was higher for first-line therapy for patients with BRAF-mutant melanoma (68%, n = 19). For the management of patients with CNS metastases, 40% of HCP therapy selections were not aligned with KOLs (n = 40). More than one half (56%) of HCPs noted that the tool confirmed their treatment plan, and 21% intend to change practice to align with KOLs. Conclusions: This analysis identified areas of discordance in clinical practice between HCPs and KOLs for advanced melanoma that can guide further education and enhance communication of evolving evidence to HCPs. Our data suggest that use of the decision tool can confirm best practices with KOL recommendations and improve alignment of treatment choices with KOLs. [Table: see text]

Abstract 4371: ERBB4 heterodimers appear to drive BRAFWT melanoma cell lines

Abstract Purpose of The Study: To determine whether heterodimerization of ERBB4 with EGFR or ERBB2 drives the proliferation of BRAF WT melanoma cell lines. Introduction: Metastatic melanomas that possess wild-type (WT) BRAF alleles are just as aggressive as melanomas that harbor gain-of-function (e.g., V600E) BRAF alleles. Moreover, no targets for effective chemotherapeutic intervention (other than immune checkpoint inhibitors) have been identified for these tumors. Thus, our goal is to identify candidate targets for therapeutic intervention in BRAF WT melanomas. ERBB4 (HER4) is a receptor tyrosine kinase that is closely related to the epidermal growth factor receptor (EGFR/ERBB1/HER1), ERBB2 (Neu/HER2), and ERBB3 (HER3). We have previously demonstrated that ERBB4 is both sufficient and necessary for the proliferation of BRAF WT melanoma cell lines. However, the constitutively homodimerized ERBB4 Q646C mutant inhibits the proliferation of BRAF WT melanoma cell lines. We have also previously demonstrated that ERBB4-EGFR and ERBB4-ERBB2 heterodimers stimulate proliferation and other oncogenic phenotypes in a variety of tumor model systems. Hence, here we test the hypothesis that ERBB4-EGFR or ERBB4-ERBB2 heterodimers drive BRAF WT melanomas. Experimental Approach: We are testing whether wild-type EGFR or ERBB2 alleles stimulate the proliferation of four different human BRAF WT melanoma cell lines. We are testing whether the dominant-negative EGFR (K721A) or ERBB2 (K753A) mutant alleles inhibit the proliferation of these cell lines. Likewise, we are testing whether EGFR or ERBB2 shRNAs inhibit the proliferation of these cell lines. Finally, we are testing whether EGFR or ERBB2 enables ERBB4 mutant alleles found in BRAF WT melanoma samples to drive greater levels of proliferation in 32D cells than wild-type ERBB4. Unpublished Results: Wild-type ERBB2 causes a significant increase in the proliferation of the MEL-JUSO and IPC-298 BRAF WT female melanoma cell lines. The ERBB2 dominant-negative allele causes a significant decrease in the proliferation of these cell lines. Finally, preliminary data suggest that the EGFR and ERBB2 dominant-negative alleles inhibit the proliferation of the MeWo BRAF WT male melanoma cell line. Preliminary Conclusions: Our data suggest that ERBB2-ERBB4 heterodimers drive two female BRAF WT melanoma cell lines, whereas ERBB2-ERBB4 and EGFR-ERBB4 heterodimers drive a male BRAF WT melanoma cell line. Thus, we predict that FDA-approved ERBB2 inhibitors (and in some cases, EGFR inhibitors) may be effective in ERBB4-dependent, BRAF WT melanomas. Moreover, ERBB4 heterodimerization with ERBB2 or EGFR may account for the gender disparities observed in BRAF WT melanomas. Citation Format: Vipasha Dwivedi, Lauren M. Lucas, Jen Davis, Kaitlyn O'Daniel, Rees H. Cooke, Joelle N. Woggerman, Ella N. Wilson, Maddy N. Ingrao, David J. Riese. ERBB4 heterodimers appear to drive BRAFWT melanoma cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4371.

Therapeutic Strategies in BRAF V600 Wild-Type Cutaneous Melanoma.

There have been many recent advances in melanoma therapy. While 50% of melanomas have a BRAF mutation and are a target for BRAF inhibitors, the remaining 50% are BRAF wild-type. Immune checkpoint inhibitors targeting PD-1, cytotoxic T-lymphocyte-associated protein 4 (CTLA4) and lymphocyte activated gene-3 (Lag-3) are all approved for the treatment of patients with advanced BRAF wild-type melanoma; however, treatment of this patient population following initial immune checkpoint blockade is a current therapeutic challenge given the lack of other efficacious options. Here, we briefly review available US FDA-approved therapies for BRAF wild-type melanoma and focus on developing treatment avenues for this heterogeneous group of patients. We review the basics of genomic features of both BRAF mutant and BRAF wild-type melanoma as well as efforts underway to develop new targeted therapies involving the mitogen-activated protein kinase (MAPK) pathway for patients with BRAF wild-type tumors. We then focus on novel immunotherapies, including developing checkpoint inhibitors and agonists, cytokine therapies, oncolytic viruses and tumor-infiltrating lymphocytes, all of which represent potential therapeutic avenues for patients with BRAF wild-type melanoma who progress on currently approved immune checkpoint inhibitors.

Proton Craniospinal Irradiation with Immunotherapy in Two Patients with Leptomeningeal Disease from Melanoma.

Proton craniospinal irradiation (pCSI) is a treatment option for leptomeningeal disease (LMD), which permits whole neuroaxis treatment while minimizing toxicity. Despite this, patients inevitably experience progression. Adding systemic therapy to pCSI may improve outcomes. In this single-institution retrospective case series, we present the feasibility of treatment with pCSI (30Gy, 10 fractions) and an immune checkpoint inhibitor (ICI) in two sequential patients with LMD from melanoma. The first patient developed LMD related to BRAF V600E-mutant melanoma after prior ICI and BRAF-targeted therapy. After pCSI with concurrent nivolumab, the addition of relatlimab, and BRAF-targeted therapy, he remained alive 7 months after LMD diagnosis despite central nervous system progression. The second patient developed LMD related to BRAF-wildtype melanoma after up-front ICI. He received pCSI with concurrent ipilimumab and nivolumab, then nivolumab maintenance. Though therapy was held for ICI hepatitis, the patient remained progression-free 5 months after LMD diagnosis. Adding an ICI to pCSI is feasible for patients with LMD and demonstrates a tolerable toxicity profile. While prospective evaluation is ultimately warranted, pCSI with ICI may confer survival benefits, even after prior ICI.

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

BackgroundMEK 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.MethodsThe 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.ResultsDiethyldithiocarbamate 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.ConclusionsDisulfiram 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.

Local treatment of liver metastasis in a patient with advanced malignant melanoma: A case report.

Melanoma is a fatal malignant tumor with a high rate of metastasis. Liver metastasis of melanoma is always associated with insensitivity to immunotherapy and a poor prognosis. However, the combination of cryoablation, which is believed to stimulate the antitumor immune response in the body, with immunotherapy can improve the therapeutic response to this condition. Herein, we present the case of a 79-year-old woman with BRAF (B-Raf proto-oncogene) wild-type melanoma who later developed liver metastasis. The patient received intravenous antiprogrammed cell death 1 antibody, which showed poor efficacy, and subsequent treatment with immunotherapy combined with cryoablation yielded a partial response. However, after the second cryoablation, the patient refused further treatment due to a fear of bleeding. Therefore, only immunotherapy was provided, which resulted in disease progression. This report demonstrates the need to consider immunotherapy plus cryoablation for the treatment of liver metastases in patients with BRAF wild-type melanoma.

Exploring the In Vitro and In Vivo Therapeutic Potential of BRAF and MEK Inhibitor Combination in NRAS-Mutated Melanoma.

Patients with NRAS-mutant metastatic melanoma often have an aggressive disease requiring a fast-acting, effective therapy. The MEK inhibitor binimetinib shows an overall response rate of 15% in patients with NRAS-mutant melanoma, providing a backbone for combination strategies. Our previous studies demonstrated that in NRAS-mutant melanoma, the antitumor activity of the MEK inhibitor binimetinib was significantly potentiated by the BRAFV600E/K inhibitor encorafenib through the induction of ER stress, leading to melanoma cell death by apoptotic mechanisms. Encorafenib combined with binimetinib was well tolerated in a phase III trial showing potent antitumor activity in BRAF-mutant melanoma, making a rapid evaluation in NRAS-mutant melanoma imminently feasible. These data provide a mechanistic rationale for the evaluation of binimetinib combined with encorafenib in preclinical and clinical studies on NRAS-mutant metastatic melanoma. The combination of BRAFi plus MEKi was tested in a monolayer culture of patient-derived cell lines and in corresponding patient-derived tissue slice cultures of NRAS-mutant melanoma. To investigate the treatment in vivo, NSG (NOD. Cg-PrkdcscidIl2rgtm1Wjl/SzJ) mice were subcutaneously injected with three different BRAF wild-type melanoma models harboring oncogenic NRAS mutations and treated orally with encorafenib (6 mg/kg body weight, daily) with or without binimetinib (8 mg/kg body weight, twice daily). In parallel, an individual healing attempt was carried out by treating one patient with an NRAS-mutated tumor. Encorafenib was able to enhance the inhibitory effect on cell growth of binimetinib only in the cell line SKMel147 in vitro. It failed to enhance the apoptotic effect found in two other NRAS-mutated cell lines. Encorafenib led to a hyperactivation of ERK which could be reduced with the combinational treatment. In two of the three patient-derived tissue slice culture models of NRAS-mutant melanomas, a slight tendency of a combinatorial effect was seen which was not significant. Encorafenib showed a slight induction of the ER stress genes ATF4, CHOP, and NUPR1. The combinational treatment was able to enhance this effect, but not significantly. In the mouse model, the combination therapy of encorafenib with binimetinib resulted in reduced tumor growth compared to the control and encorafenib groups; however, the best effect in terms of tumor growth inhibition was measured in the binimetinib therapy group. The therapy showed no effect in an individual healing attempt for a patient suffering from metastatic, therapy-refractory NRAS-mutated melanoma. In in vitro and ex vivo settings, the combination therapy was observed to elicit a response; however, it did not amplify the efficacy observed with binimetinib alone, whereas in a patient, the combinational treatment remained ineffective. The preclinical in vivo data showed no increased combinatorial effect. However, the in vivo effect of binimetinib as monotherapy was unexpectedly high in the tested regimen. Nevertheless, binimetinib proved to be advantageous in the treatment of melanoma in vivo and led to high rates of apoptosis in vitro; hence, it still seems to be a good base for combination with other substances in the treatment of patients with NRAS-mutant melanoma.

RADT-18. PROTON CRANIOSPINAL IRRADIATION WITH CHECKPOINT INHIBITOR THERAPY FOR PATIENTS WITH LEPTOMENINGEAL DISEASE FROM SOLID TUMORS – A SINGLE INSTITUTION CASE SERIES

Abstract BACKGROUND Leptomeningeal disease (LMD) is a devastating complication of cancer with median overall survival (OS) of 3-6 months following diagnosis. Proton craniospinal irradiation (pCSI) is a novel treatment option for LMD, permitting whole neuroaxis treatment with tolerable toxicity and improved efficacy compared to conventional photon whole brain radiation therapy and as needed focal spine radiotherapy. Despite this, patients experience progression and succumb to LMD. Addition of systemic therapy to pCSI may improve outcomes. METHODS In this single institution retrospective case series, we report feasibility of combination treatment with pCSI and immune checkpoint inhibitor (ICI) in patients with LMD from solid tumors. RESULTS Three patients were treated with pCSI (30 Gy in 10 fractions) and ICI. The first patient developed LMD related to large cell neuroendocrine carcinoma of lung primary, diagnosed by imaging and cytology, having previously undergone resection and stereotactic radiosurgery for brain metastases. Clinical and radiographic improvement was noted following pCSI, bevacizumab, and pembrolizumab therapy. Patient experienced disease progression and passed away only after ICI was held due to hypophysitis, with 6-month OS. The second patient developed LMD related to BRAF V600E mutant melanoma, diagnosed by imaging and cytology, having previously undergone ICI and BRAF-targeted therapy. Following pCSI, relatlimab, nivolumab, and BRAF-targeted therapy, the patient remains alive 7 months after LMD diagnosis despite radiographic progression treated with carboplatin, paclitaxel, intrathecal IL-2, ipilimumab, and bevacizumab. The third developed LMD related to BRAF-wildtype melanoma, diagnosed by imaging, having previously received ICI. Patient underwent pCSI followed by ipilimumab and nivolumab, progression-free 5 months after LMD diagnosis. CONCLUSION Addition of systemic therapy to pCSI is feasible for patients with LMD. Combination of ICI and pCSI may confer additional survival benefit, even among patients with prior exposure to ICI. These initial promising results warrant prospective evaluation.

Melanoma-the therapeutic considerations in the clinical practice.

The incidence of melanoma is increasing and prolonged exposure to ultraviolet (UV) radiation remains the main risk factor. Public health measures have been vital in tackling the increased incidence and prevalence of melanoma. The management of melanoma has been revolutionised with the approval of new immunotherapy treatments (anti PD-1, CTLA-4 and LAG-3 antibodies) and targeted therapies (BRAF and MEK inhibitors). With some of these therapies becoming the standard of care in the management of advanced disease, it is likely we will see their use increase in the adjuvant and neoadjuvant setting. Recently, literature has demonstrated the benefits patients could derive from the combination of immune checkpoint inhibitors (ICIs) due to the promising results on its efficacy when compared to monotherapy. However, greater clarity on its use is needed in more unique presentations such as BRAF-wild type melanoma, where the lack of driver mutations makes disease management more challenging. Surgical resection remains an integral part of the management of earlier stages of the disease with a consequent decrease in reliance on other forms of therapy such as chemotherapy and radiotherapy. Finally, we evaluated the novel emerging experimental approaches to treatment such as adoptive T cell therapy, novel oncolytic treatments and cancer vaccines. We discussed how their use could improve patients' prognosis, enhance treatment efficacy, and potentially achieve cure.

Factors influencing the prognosis in Braf wild-type metastatic malignant melanoma and the role of novel inflammation indices

Factors influencing the prognosis in Braf wild-type metastatic malignant melanoma and the role of novel inflammation indices

Bioinformatics-based analysis reveals elevated CYTL1 as a potential therapeutic target for BRAF-mutated melanoma.

Introduction: Despite many recent emerging therapeutic modalities that have prolonged the survival of melanoma patients, the prognosis of melanoma remains discouraging, and further understanding of the mechanisms underlying melanoma progression is needed. Melanoma patients often have multiple genetic mutations, with BRAF mutations being the most common. In this study, public databases were exploited to explore a potential therapeutic target for BRAF-mutated melanoma. Methods: In this study, we analyzed differentially expressed genes (DEGs) in normal tissues and melanomas, Braf wild-type and Braf mutant melanomas using information from TCGA databases and the GEO database. Subsequently, we analyzed the differential expression of CYTL1 in various tumor tissues and its effect on melanoma prognosis, and resolved the mutation status of CYTL1 and its related signalling pathways. By knocking down CYTL1 in melanoma cells, the effects of CYTL1 on melanoma cell proliferation, migration and invasion were further examined by CCK8 assay, Transwell assay and cell migration assay. Results: 24 overlapping genes were identified by analyzing DEGs common to melanoma and normal tissue, BRAF-mutated and BRAF wild-type melanoma. Among them, CYTL1 was highly expressed in melanoma, especially in BRAF-mutated melanoma, and the high expression of CYTL1 was associated with epithelial-mesenchymal transition (EMT), cell cycle, and cellular response to UV. In melanoma patients, especially BRAF-mutated melanoma patients, clinical studies showed a positive correlation between increased CYTL1 expression and shorter overall survival (OS) and disease-free survival (DFS). In vitro experiments further confirmed that the knockdown of CYTL1 significantly inhibited the migration and invasive ability of melanoma cells. Conclusion: CYTL1 is a valuable prognostic biomarker and a potentially effective therapeutic target in melanoma, especially BRAF-mutated melanoma.

MiR-224–5p acts as a tumour suppressor and reverses the resistance to BRAF inhibitor in melanoma through directly targeting PAK4 to block the MAPK pathway

miR-224–5p has been shown to play both an oncogene and tumour suppressor role in many human tumours. However, the role and molecular mechanism of miR-224–5p in cutaneous melanoma remains unclear. miR-224–5p levels were downregulated in melanoma tissue, and low miR-224–5p expression was an independent risk factor for melanoma patients. miR-224–5p blocked proliferation, epithelial-to-mesenchymal transition (EMT), invasion, migration in BRAF wild-type melanoma cell, and overcome acquired BRAFi resistance in VMF-resistant melanoma cells. miR-224–5p exerted its role by directly repressing PAK4 to block the downstream CRAF/MEK/ERK pathways. We demonstrated that miR-224–5p inhibited melanoma growth and metastasis in vivo though xenograft tumor and pulmonary metastasis assay. Thus, miR-224–5p/PAK4-mediated CRAF/MEK/ERK pathways have therapeutic potential in melanoma treatment.

Targeting Prohibitins to Inhibit Melanoma Growth and Overcome Resistance to Targeted Therapies.

Despite important advances in the treatment of metastatic melanoma with the development of MAPK-targeted agents and immune checkpoint inhibitors, the majority of patients either do not respond to therapies or develop acquired resistance. Furthermore, there is no effective targeted therapy currently available for BRAF wild-type melanomas (approximately 50% of cutaneous melanoma). Thus, there is a compelling need for new efficient targeted therapies. Prohibitins (PHBs) are overexpressed in several types of cancers and implicated in the regulation of signaling networks that promote cell invasion and resistance to cell apoptosis. Herein, we show that PHBs are highly expressed in melanoma and are associated with not only poor survival but also with resistance to BRAFi/MEKi. We designed and identified novel specific PHB inhibitors that can inhibit melanoma cell growth in 3D spheroid models and a large panel of representative cell lines with different molecular subtypes, including those with intrinsic and acquired resistance to MAPKi, by significantly moderating both MAPK (CRAF-ERK axis) and PI3K/AKT pathways, and inducing apoptosis through the mitochondrial pathway and up-regulation of p53. In addition, autophagy inhibition enhances the antitumor efficacy of these PHB ligands. More important, these ligands can act in synergy with MAPKi to more efficiently inhibit cell growth and overcome drug resistance in both BRAF wild-type and mutant melanoma. In conclusion, targeting PHBs represents a very promising therapeutic strategy in melanoma, regardless of mutational status.

The benefit of co-targeting PARP-1 and c-Met on the efficacy of radiotherapy in wild type BRAF melanoma.

Melanoma is known to be a radioresistant cancer. Melanoma radioresistance can be due to several factors such as pigmentation, antioxidant defenses and high Deoxyribonucleic acid (DNA) repair efficacy. However, irradiation induces intracellular translocation of RTKs, including cMet, which regulates response to DNA damage activating proteins and promotes DNA repair. Accordingly, we hypothesized that co-targeting DNA repair (PARP-1) and relevant activated RTKs, c-Met in particular, may radiosensitize wild-type B-Raf Proto-Oncogene, Serine/Threonine Kinase (WTBRAF) melanomas where RTKs are often upregulated. Firstly, we found that PARP-1 is highly expressed in melanoma cell lines. PARP-1 inhibition by Olaparib or its KO mediates melanoma cell sensitivity to radiotherapy (RT). Similarly, specific inhibition of c-Met by Crizotinib or its KO radiosensitizes the melanoma cell lines. Mechanistically, we show that RT causes c-Met nuclear translocation to interact with PARP-1 promoting its activity. This can be reversed by c-Met inhibition. Accordingly, RT associated with the inhibition of both c-Met and PARP-1 resulted in a synergistic effect not only on tumor growth inhibition but also on tumor regrowth control in all animals following the stop of the treatment. We thus show that combining PARP and c-Met inhibition with RT appears a promising therapeutic approach in WTBRAF melanoma.

Prognostic and predictive value of metformin in the European Organisation for Research and Treatment of Cancer 1325/KEYNOTE-054 phase III trial of pembrolizumab versus placebo in resected high-risk stage III melanoma

BackgroundMetformin is a commonly prescribed and well-tolerated medication. In laboratory studies, metformin suppresses BRAF wild-type melanoma cells but accelerates the growth of BRAF-mutated cells. This study investigated the prognostic and predictive value of metformin, including with respect to BRAF mutation status, in the European Organisation for Research and Treatment of Cancer 1325/KEYNOTE-054 randomised controlled trial. MethodsPatients with resected high-risk stage IIIA, IIIB, or IIIC melanoma received 200 mg of pembrolizumab (n = 514) or placebo (n = 505) every 3 weeks for twelve months. Pembrolizumab prolonged recurrence-free survival (RFS) and distant metastasis-free survival (DMFS) at approximately 42 months median follow-up (Eggermont et al., TLO, 2021). Multivariable Cox regression was used to estimate associations of metformin with RFS and DMFS. Interaction terms were used to model effect modification by treatment and BRAF mutation. ResultsFifty-four patients (0.5%) used metformin at baseline. Metformin was not significantly associated with RFS (hazard ratio [HR] 0.87, 95% confidence interval [CI] 0.52–1.45) and DMFS (HR 0.82, 95% CI 0.47–1.44). The interaction between metformin and the treatment arm was not significant for either RFS (p = 0.92) or DMFS (p = 0.93). Among patients with mutated BRAF, the association of metformin with RFS (HR 0.70, 95% CI 0.37–1.33) was greater in magnitude though not significantly different to those without mutated BRAF (HR 0.98, 95% CI 0.56–1.69). ConclusionsThere was no significant impact of metformin use on pembrolizumab efficacy in resected high-risk stage III melanoma. However, larger studies or pooled analyses are needed, particularly to explore a possible effect of metformin in BRAF-mutated melanoma.

Analyzing the relationship between the efficacy of first-line immune checkpoint inhibitors and cumulative sun damage in Japanese patients with advanced BRAF wild-type nonacral cutaneous melanoma: A retrospective real-world, multicenter study

BackgroundEfficacy of anti-PD-1 antibody monotherapy (PD1) or anti-PD-1 plus anti-CTLA-4 combination therapy (PD1 +CTLA4) for melanoma is affected by its clinical subtype. The amount of tumor mutation burden (TMB) caused by cumulative sun damage (CSD) is occasionally used to explain this; however, their relationship in Japanese nonacral cutaneous melanoma (NACM) is still unclear. ObjectiveTo analyze the ICI efficacy and its relationship with CSD of the primary lesion in Japanese patients with NACM. MethodsJapanese patients with advanced BRAF wild-type NACM who received first-line ICIs were recruited. Objective response rate (ORR), progression-free survival (PFS), and overall survival (OS), and the degree of solar elastosis (SE) were evaluated. ResultsA total of 146 patients (PD1 group 113 and PD1 +CTLA4 group 33) were included. No significant differences in ORR were observed between the PD1 and PD1 +CTLA4 groups (35 % vs. 36 %; P = 0.67) or PFS and OS (median PFS 6.1 months vs. 8.5 months; P = 0.46, median OS 28.1 months vs. not reached; P = 0.59). Multivariate survival analysis revealed that PD1 +CTLA4 did not prolong the PFS and OS. The SE score had no effect on either PFS or OS. ConclusionsICI efficacy was not as high as those reported in Western countries, and PD1 +CTLA4 did not present better clinical efficacy compared to PD1. Indicators of CSD did not serve as a predictor for clinical advantage. These findings may partially support the theory that ICI efficacy is affected by CSD; however, other unrecognized factors may also exist.

Real-life use of trametinib after immunotherapy failure in BRAF wild-type advanced melanoma.

BRAF V600 wild-type advanced melanomas quickly reach a therapeutic dead-end, after immunotherapy failure. Even if preclinical studies have suggested sensitivity to MEK inhibitors such as trametinib in NRAS, NF1 or GNA mutated melanoma, therapeutic options are limited for these patients. We present a retrospective monocentric study of 22 patients with advanced melanoma treated by trametinib after immunotherapy resistance. Melanomas harboured NRAS (20), NF1 (1) or GNA 11 (1) mutations. For most of them (18), anti-PD1 was associated with trametinib. A disease-control was reported in 36% of patients (8/22), with six stable diseases and two partial responses according to Response Evaluation Criteria in Solid Tumors (RECIST) criteria. Median progression-free survival was 2 months (1-14) and median overall survival was 6.5 months (2-24). In patients with progressive disease (14/22), dissociated radiologic responses and clinical benefits such as pain reduction were seen in five patients. High blood level of lactate dehydrogenase (LDH) seemed associated with trametinib failure, without significance ( P = 0.06). Adverse events (grade 1-3) occurred in 91% of patients during the first weeks of treatment, mainly papulo-pustular rashes (77%), leg oedemas (36%), asthenia (18%) and diarrhoea (14%). This real-life study showed that trametinib may benefit some metastatic melanoma that progressed after chemotherapy and immune checkpoint inhibitors. Objective disease control (partial response or stable disease) using RECIST criteria was observed in 36% of patients. Because of frequent side-effects which can alter the quality of life and the short response duration, this off-label option has to be discussed with the patient. Studies with combination therapy with trametinib to improve relapse-free survival and lower side-effects are ongoing.