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

Targeted Therapy Innovations for Melanoma

Melanoma, a malignant tumor of melanocytes, poses a significant clinical challenge due to its aggressive nature and high potential for metastasis. The advent of targeted therapy has revolutionized the treatment landscape of melanoma, particularly for tumors harboring specific genetic alterations such as BRAF V600E mutations. Despite the initial success of targeted agents, resistance inevitably arises, underscoring the need for novel therapeutic strategies. This review explores the latest advances in targeted therapy for melanoma, focusing on new molecular targets, combination therapies, and strategies to overcome resistance.

Latent-Transforming Growth Factor β-Binding Protein 1/Transforming Growth Factor β1 Complex Drives Antitumoral Effects upon ERK5 Targeting in Melanoma

Melanoma is the deadliest skin cancer, with a poor prognosis in advanced stages. While available treatments have improved survival, long-term benefits are still unsatisfactory. The mitogen-activated protein kinase extracellular signal-regulated kinase 5 (ERK5) promotes melanoma growth, and ERK5 inhibition determines cellular senescence and the senescence-associated secretory phenotype. Here, latent-transforming growth factor β-binding protein 1 (LTBP1) mRNA was found to be up-regulated in A375 and SK-Mel-5 BRAF V600E melanoma cells after ERK5 inhibition. In keeping with a key role of LTBP1 in regulating transforming growth factor β (TGF-β), TGF-β1 protein levels were increased in lysates and conditioned media of ERK5-knockdown (KD) cells, and were reduced upon LTBP1 KD. Both LTBP1 and TGF-β1 proteins were increased in melanoma xenografts in mice treated with the ERK5 inhibitor XMD8-92. Moreover, treatment with conditioned media from ERK5-KD melanoma cells reduced cell proliferation and invasiveness, and TGF-β1-neutralizing antibodies impaired these effects. In silico data sets revealed that higher expression levels of both LTBP1 and TGF-β1 mRNA were associated with better overall survival of melanoma patients. Increased LTBP1 or TGF-β1 expression played a beneficial role in patients treated with anti-PD1 immunotherapy, making a possible immunosuppressive role of LTBP1/TGF-β1 unlikely upon ERK5 inhibition. This study, therefore, identifies additional desirable effects of ERK5 targeting, providing evidence of an ERK5-dependent tumor-suppressive role of TGF-β in melanoma.

Malignant Melanoma: An Overview, New Perspectives, and Vitamin D Signaling

Melanoma, originating through malignant transformation of melanin-producing melanocytes, is a formidable malignancy, characterized by local invasiveness, recurrence, early metastasis, resistance to therapy, and a high mortality rate. This review discusses etiologic and risk factors for melanoma, diagnostic and prognostic tools, including recent advances in molecular biology, omics, and bioinformatics, and provides an overview of its therapy. Since the incidence of melanoma is rising and mortality remains unacceptably high, we discuss its inherent properties, including melanogenesis, that make this disease resilient to treatment and propose to use AI to solve the above complex and multidimensional problems. We provide an overview on vitamin D and its anticancerogenic properties, and report recent advances in this field that can provide solutions for the prevention and/or therapy of melanoma. Experimental papers and clinicopathological studies on the role of vitamin D status and signaling pathways initiated by its active metabolites in melanoma prognosis and therapy are reviewed. We conclude that vitamin D signaling, defined by specific nuclear receptors and selective activation by specific vitamin D hydroxyderivatives, can provide a benefit for new or existing therapeutic approaches. We propose to target vitamin D signaling with the use of computational biology and AI tools to provide a solution to the melanoma problem.

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.

Multilayered Microneedles for Triphasic Controlled Delivery of Small Molecules and Proteins

Transdermal delivery is an attractive delivery method that increases bioavailability, is suitable for a wide variety of therapeutics, and offers stable delivery outcomes. However, many therapeutics are unable to readily cross the stratum corneum. Microneedles mechanically disrupt the cutaneous barrier to deliver small molecules, proteins, and vaccines. To date, microneedles have not been used in conjunction with coacervate, a liquid-liquid phase separation that protects unstable proteins. A three-layer microneedle for the controlled release of three different molecules is designed. Through micromolding, microneedles are efficiently generated, which benefits product scalability. The microneedles have good mechanical integrity and effectively penetrate porcine skin ex vivo. The three layers, in the microneedles, release the cargo in a three-phase manner. The released protein maintains its structure well. Moreover, layer thickness can be controlled by varying fabrication parameters. The microneedles can incorporate both small molecule drugs and protein therapeutics, thus promising uses in multi-drug therapies through a single treatment.

ALDH2 is a novel biomarker and exerts an inhibitory effect on melanoma

Melanoma is a malignant skin tumor. This study aimed to explore and assess the effect of novel biomarkers on the progression of melanoma. Differently expressed genes (DEGs) were screened from GSE3189 and GSE46517 datasets of Gene Expression Omnibus database using GEO2R. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses were conducted based on the identified DEGs. Hub genes were identified and assessed using protein-protein interaction networks, principal component analysis, and receiver operating characteristic curves. Quantitative real-time polymerase chain reaction was employed to measure the mRNA expression levels. TIMER revealed the association between aldehyde dehydrogenase 2 (ALDH2) and tumor immune microenvironment. The viability, proliferation, migration, and invasion were detected by cell counting kit-8, 5-ethynyl-2'-deoxyuridine, wound healing, and transwell assays. Total 241 common DEGs were screened out from GSE3189 and GSE46517 datasets. We determined 6 hub genes with high prediction values for melanoma, which could distinguish tumor samples from normal samples. ALDH2, ADH1B, ALDH3A2, DPT, EPHX2, and GATM were down-regulated in A375 and SK-MEL-2 cells, compared with the human normal melanin cell line (PIG1 cells). ALDH2 was selected as the candidate gene in this research, presenting a high diagnostic and predictive value for melanoma. ALDH2 had a positive correlation with the infiltrating levels of immune cells in melanoma microenvironment. Overexpression of ALDH2 inhibited cell viability, proliferation, migration, and invasion of A375/SK-MEL-2 cells. ALDH2 is a new gene biomarker of melanoma, which exerts an inhibitory effect on melanoma.

CD133-Dependent Activation of Phosphoinositide 3-Kinase /AKT/Mammalian Target of Rapamycin Signaling in Melanoma Progression and Drug Resistance

Melanoma frequently harbors genetic alterations in key molecules leading to the aberrant activation of PI3K and its downstream pathways. Although the role of PI3K/AKT/mTOR in melanoma progression and drug resistance is well documented, targeting the PI3K/AKT/mTOR pathway showed less efficiency in clinical trials than might have been expected, since the suppression of the PI3K/mTOR signaling pathway-induced feedback loops is mostly associated with the activation of compensatory pathways such as MAPK/MEK/ERK. Consequently, the development of intrinsic and acquired resistance can occur. As a solid tumor, melanoma is notorious for its heterogeneity. This can be expressed in the form of genetically divergent subpopulations including a small fraction of cancer stem-like cells (CSCs) and non-cancer stem cells (non-CSCs) that make the most of the tumor mass. Like other CSCs, melanoma stem-like cells (MSCs) are characterized by their unique cell surface proteins/stemness markers and aberrant signaling pathways. In addition to its function as a robust marker for stemness properties, CD133 is crucial for the maintenance of stemness properties and drug resistance. Herein, the role of CD133-dependent activation of PI3K/mTOR in the regulation of melanoma progression, drug resistance, and recurrence is reviewed.

Low-molecular-weight fucoidan inhibits the proliferation of melanoma via Bcl-2 phosphorylation and PTEN/AKT pathway

Fucoidan, a sulfate polysaccharide obtained from brown seaweed, has various bioactive properties, including anti-inflammatory, anti-cancer, anti-viral, anti-oxidant, anti-coagulant, anti-thrombotic, anti-angiogenic, and anti-Helicobacter pylori properties. However, the effects of low-molecular-weight fucoidan (LMW-F) on melanoma cell lines and three dimensional (3D) cell culture models are not well understood. This study aimed to investigate the effects of LMW-F on A375 human melanoma cells and cryopreserved biospecimens derived from patients with advanced melanoma. Ultrasonic wave was used to fragment fucoidan derived from Fucus vesiculosus into smaller LMW-F. MTT and live/dead assays showed that LMW-F inhibited cell proliferation in both A375 cells and patient-derived melanoma explants in a 3D-printed collagen scaffold. The PTEN/AKT pathway was found to be involved in the anti-melanoma effects of fucoidan. Western blot analysis revealed that LMW-F reduced the phosphorylation of Bcl-2 at Thr 56, which was associated with the prevention of anti-apoptotic activity of cancer cells. Our findings suggested that LMW-F could enhance anti-melanoma chemotherapy and improve the outcomes of patients with melanoma resistance.

Combining CSPG4-CAR and CD20-CCR for treatment of metastatic melanoma

The prognosis for patients with metastatic melanoma is poor and treatment options are limited. Genetically-engineered T cell therapy targeting chondroitin sulfate proteoglycan 4 (CSPG4), however, represents a promising treatment option, especially as both primary melanoma cells as well as metastases uniformly express CSPG4. Aiming to prevent off-tumor toxicity while maintaining a high cytolytic potential, we combined a chimeric co-stimulatory receptor (CCR) and a CSPG4-directed second-generation chimeric antigen receptor (CAR) with moderate potency. CCRs are artificial receptors similar to CARs, but lacking the CD3ζ activation element. Thus, T cells expressing solely a CCR, do not induce any cytolytic activity upon target cell binding, but are capable of boosting the CAR T cell response when both CAR and CCR engage their target antigens simultaneously. Here we demonstrate that co-expression of a CCR can significantly enhance the anti-tumor response of CSPG4-CAR T cells in vitro as well as in vivo. Importantly, this boosting effect was not dependent on co-expression of both CCR- and CAR-target on the very same tumor cell, but was also achieved upon trans activation. Finally, our data support the idea of using a CCR as a powerful tool to enhance the cytolytic potential of CAR T cells, which might open a novel therapeutic window for the treatment of metastatic melanoma.

Unexpected and Rare Sites of Metastasis in Oncologic Patients

Case studies of rare oncologic metastases are an important source of clinical data for health care professionals and researchers. While infrequent, the knowledge base and clinical recommendations derived from such cases aid in advancements in the field. As such, we aim to add five cases to the growing body of literature. The first two male patients, aged 69 and 73, were diagnosed with colon adenocarcinoma, suspected to be a second primary prostate carcinoma, following positron emission tomography-computer tomography (PET-CT). This suspicion was ruled out by prostatectomy and histopathological investigations, which instead found adenocarcinoma of colonic origin. The next two male patients, ages 63 and 68, were diagnosed, respectively, with metastatic pancreatic adenocarcinoma with cardiac metastases and metastatic melanoma with distant metastases to the pancreas. The final patient was a 73-year-old male diagnosed with metastatic breast cancer after a radiological investigation of suspected renal cell carcinoma.

c-Kit Receptors as a Therapeutic Target in Cancer: Current Insights

c-Kit is a type III receptor tyrosine kinase (RTK) that has an essential role in various biological functions including gametogenesis, melanogenesis, hematopoiesis, cell survival, and apoptosis. c-KIT aberrations, either overexpression or loss-of-function mutations, have been implicated in the pathogenesis and development of many cancers, including gastrointestinal stromal tumors, mastocytosis, acute myeloid leukemia, breast, thyroid, and colorectal cancer, making c-KIT an attractive molecular target for the treatment of cancers. Therefore, a lot of effort has been put into investigating the utility of tyrosine kinase inhibitors for the management of c-KIT mutated tumors. This review of the literature illustrates the role of c-KIT mutations in many cancers, aiming to provide insights into the role of TKIs as a therapeutic option for cancer patients with c-KIT aberrations. In conclusion, c-KIT is implicated in different types of cancer, and it could be a successful molecular target; however, proper detection of the underlying mutation type is required before starting the appropriate personalized therapy.

Artificial Intelligence and Radiomics: Clinical Applications for Patients with Advanced Melanoma Treated with Immunotherapy

Immunotherapy has greatly improved the outcomes of patients with metastatic melanoma. However, it has also led to new patterns of response and progression, creating an unmet need for better biomarkers to identify patients likely to achieve a lasting clinical benefit or experience immune-related adverse events. In this study, we performed a focused literature survey covering the application of artificial intelligence (AI; in the form of radiomics, machine learning, and deep learning) to patients diagnosed with melanoma and treated with immunotherapy, reviewing 12 studies relevant to the topic published up to early 2022. The most commonly investigated imaging modality was CT imaging in isolation (n = 9, 75.0%), while patient cohorts were most frequently recruited retrospectively and from single institutions (n = 7, 58.3%). Most studies concerned the development of AI tools to assist in prognostication (n = 5, 41.7%) or the prediction of treatment response (n = 6, 50.0%). Validation methods were disparate, with two studies (16.7%) performing no validation and equal numbers using cross-validation (n = 3, 25%), a validation set (n = 3, 25%), or a test set (n = 3, 25%). Only one study used both validation and test sets (n = 1, 8.3%). Overall, promising results have been observed for the application of AI to immunotherapy-treated melanoma. Further improvement and eventual integration into clinical practice may be achieved through the implementation of rigorous validation using heterogeneous, prospective patient cohorts.

In Silico Studies of Novel Vemurafenib Derivatives as BRAF Kinase Inhibitors

BRAF inhibitors have improved the treatment of advanced or metastatic melanoma in patients that harbor a BRAF^T1799A mutation. Because of new insights into the role of aberrant glycosylation in drug resistance, we designed and studied three novel vemurafenib derivatives possessing pentose-associated aliphatic ligands-methyl-, ethyl-, and isopropyl-ketopentose moieties-as potent BRAF_V600E kinase inhibitors. The geometries of these derivatives were optimized using the density functional theory method. Molecular dynamic simulations were performed to find interactions between the ligands and BRAF_V600E kinase. Virtual screening was performed to assess the fate of derivatives and their systemic toxicity, genotoxicity, and carcinogenicity. The computational mapping of the studied ligand-BRAF_V600E complexes indicated that the central pyrrole and pyridine rings of derivatives were located within the hydrophobic ATP-binding site of the BRAF_V600E protein kinase, while the pentose ring and alkyl chains were mainly included in hydrogen bonding interactions. The isopropyl-ketopentose derivative was found to bind the BRAF_V600E oncoprotein with more favorable energy interaction than vemurafenib. ADME-TOX in silico studies showed that the derivatives possessed some desirable pharmacokinetic and toxicologic properties. The present results open a new avenue to study the carbohydrate derivatives of vemurafenib as potent BRAF_V600E kinase inhibitors to treat melanoma.

Biologically Interpretable Deep Learning To Predict Response to Immunotherapy In Advanced Melanoma Using Mutations and Copy Number Variations

Only 30-40% of advanced melanoma patients respond effectively to immunotherapy in clinical practice, so it is necessary to accurately identify the response of patients to immunotherapy pre-clinically. Here, we develop KP-NET, a deep learning model that is sparse on KEGG pathways, and combine it with transfer- learning to accurately predict the response of advanced melanomas to immunotherapy using KEGG pathway-level information enriched from gene mutation and copy number variation data. The KP-NET demonstrates best performance with AUROC of 0.886 on testing set and 0.803 on an unseen evaluation set when predicting responders (CR/PR/SD with PFS ≥6 mo) versus non-responders (PD/SD with PFS <6 mo) in anti-CTLA-4 treated melanoma patients. The model also achieves an AUROC of 0.917 and 0.833 in predicting CR/PR versus PD, respectively. Meanwhile, the AUROC is 0.913 when predicting responders versus non-responders in anti-PD-1/PD-L1 melanomas. Moreover, the KP-NET reveals some genes and pathways associated with response to anti-CTLA-4 treatment, such as genes PIK3CA, AOX1 and CBLB, and ErbB signaling pathway, T cell receptor signaling pathway, et al. In conclusion, the KP-NET can accurately predict the response of melanomas to immunotherapy and screen related biomarkers pre-clinically, which can contribute to precision medicine of melanoma.

An Immunogenic Cell Death-Related Gene Signature Reflects Immune Landscape and Predicts Prognosis in Melanoma Independently of BRAF V600E Status

Immunogenic cell death (ICD) is a type of regulated cell death that can activate adaptive immune response, and its ability to reshape the tumor microenvironment via multiple mechanisms may contribute to immunotherapy. The treatment options for patients with skin cutaneous melanoma (SKCM) vary based on BRAF V600E statuses. However, all standard treatments include immunotherapy. Therefore, it is critical to identify ICD-associated signatures that can help classify patients according to benefits from ICD immunotherapy. In this study, data on melanoma samples with BRAF V600E mutation (BRAF V600E-mutant melanoma) and melanoma samples with wild-type BRAF V600E alleles (BRAF V600E WT melanoma) were collected from The Cancer Genome Atlas (TCGA) database. The ICD-related (ICD-high and ICD-low) subgroups of patients with BRAF V600E WT melanoma were established via consensus clustering. The analyses of survival, differentially expressed genes (DEGs), functional annotation, and immune landscape were performed in these two subgroups. Results showed that ICD-high subgroup was correlated with a positive overall survival (OS) and active tumor immune landscape. A model comprising seven prognosis ICD-related gene biomarkers was developed. Survival analysis and receiver operating characteristic (ROC) curve evaluation in both cohorts with BRAF V600E WT and BRAF V600E-mutant melanoma showed an accurate prognostic estimation of ICD-related risk signature. There was a correlation between immune cell infiltration and immunotherapy response and risk score. Thus, the ICD risk signature was closely associated with the tumor's immune microenvironment. Our results may provide insights to further individualize and improve precision therapeutic decision-making in BRAF V600E-mutant and WT melanoma.

Antimetastatic Properties of Prodigiosin and the BH3-Mimetic Obatoclax (GX15-070) in Melanoma

Metastasis is the primary cause of death in cancer patients. Many current chemotherapeutic agents only show cytotoxic, but not antimetastatic properties. This leads to a reduction in tumor size, but allows cancer cells to disseminate, which ultimately causes patient death. Therefore, novel anticancer compounds with both effects need to be developed. In this work, we analyze the antimetastatic properties of prodigiosin and obatoclax (GX15-070), anticancer drugs of the Prodiginines (PGs) family. We studied PGs' effects on cellular adhesion and morphology in the human primary and metastatic melanoma cell lines, SK-MEL-28 and SK-MEL-5, and in the murine melanoma cell line, B16F10A. Cell adhesion sharply decreased in the treated cells, and this was accompanied by a reduction in filopodia protrusions and a significant decrease in the number of focal-adhesion structures. Moreover, cell migration was assessed through the wound-healing assay and cell motility was severely inhibited after 24 h of treatment. To elucidate the molecular mechanisms involved, changes in metastasis-related genes were analyzed through a gene-expression array. Key genes related to cellular invasion, migration and chemoresistance were significantly down-regulated. Finally, an in vivo model of melanoma-induced lung metastasis was established and significant differences in lung tumors were observed in the obatoclax-treated mice. Altogether, these results describe, in depth, PGs' cellular antimetastatic effects and identify in vivo antimetastatic properties of Obatoclax.