Cutaneous melanoma

A dendritic cell-recruiting, antimicrobial blood clot hydrogel for melanoma recurrence prevention and infected wound management

Surgical resection, the mainstay for melanoma treatment, faces challenges due to high tumor recurrence rates and complex postoperative wound healing. Chronic inflammation from residual disease and the risk of secondary infections impede healing. We introduce an innovative, injectable hydrogel system that integrates a multifaceted therapeutic approach. The hydrogel, crosslinked by calcium ions with sodium alginate, encapsulates a blood clot rich in dendritic cells (DCs) chemoattractants and melanoma cell-derived nanovesicles (NVs), functioning as a potent immunostimulant. This in situ recruitment strategy overcomes the limitations of subcutaneous tumor vaccine injections and more effectively achieves antitumor immunity. Additionally, the hydrogel incorporates Chlorella extracts, enhancing its antimicrobial properties to prevent wound infections and promote healing. One of the key findings of our research is the dual functionality of Chlorella extracts; they not only expedite the healing process of infected wounds but also increase the hydrogel's ability to stimulate an antitumor immune response. Given the patient-specific nature of the blood clot and NVs, our hydrogel system offers customizable solutions for individual postoperative requirements. This personalized approach is highlighted by our study, which demonstrates the synergistic impact of the composite hydrogel on preventing melanoma recurrence and hastening wound healing, potentially transforming postsurgical melanoma management.

The role of DGAT1 and DGAT2 in tumor progression via fatty acid metabolism: A comprehensive review

Fatty acid metabolism is a complex biochemical process, including the production, breakdown and application of fatty acids. Not only is it an important component of lipid metabolism, fatty acid metabolism is also connected to the energy metabolism pathways of cells and plays a vital role in maintaining the energy balance of organisms. Diacylglycerol-O-acyltransferase 1 (DGAT1) and Diacylglycerol-O-acyltransferase 2 (DGAT2) are key components in regulating lipid metabolism, which provide energy for cell proliferation and growth. Recent studies have shown that DGAT1 and DGAT2 influence tumor progression through fatty acid metabolism in cancer. Although DGAT1 and DGAT2 have similar names, they differ significantly in various aspects and play distinct roles in individual tumors. A comparative analysis of the physiological roles of these enzymes and their differential expressions in different types of tumors will enhance our understanding of their unique characteristics. This article summarizes the characteristics of tumor fatty acid metabolism and explains how DGAT1 and DGAT2 specifically promote tumor progression. In addition, this review discusses the potential of lipid-lowering drugs in tumor treatment, providing a new perspective on targeting fatty acid metabolism to inhibit tumor progression in the future, while emphasizing the importance of DGAT1 and DGAT2 as potential targets for tumor treatment.

Doping-Engineered Piezoelectric Ultrathin Nanosheets for Synergistically Piezo-Chemocatalytic Antitumor and Antibacterial Therapies Against Cutaneous Melanoma

The post-surgical melanoma recurrence and wound infections have persistently troubled clinical management. Piezocatalytic therapy features high efficiency in generating reactive oxygen species (ROS) for tumor therapy, but it faces limitations in piezoelectricity and redox-active site availability. Herein, Fe-doped ultrathin Bi4Ti3O12 nanosheets (designated as Fe-UBTO NSs) with synergistically piezo-chemocatalytic activity are engineered for antitumor and antibacterial treatment against cutaneous melanoma. The doping-engineered strategy induces oxygen vacancies and lattice distortions in Fe-UBTO NSs, which narrows bandgap to enhance piezocatalytic 1O2 and H2O2 generation by improving the electron-hole pairs separation, hindering their recombination, and increasing oxygen adsorption. Moreover, Fe doping establishes a piezo-chemocatalytic system, in which the piezocatalysis enables the self-supply of H2O2 and expedites electron transfer in Fenton reactions, inducing increased ·OH production. Besides, the atomic-level thickness and expanded surface area enhance the sensitivity to ultrasound stimuli and expose more redox-active sites, augmenting the piezo-chemocatalytic efficiency, and ultimately leading to abundant ROS generation. The Fe-UBTO-mediated piezo-chemocatalytic therapy causes intracellular oxidative stress, triggering apoptosis and excessive autophagy of tumor cells. Moreover, this strategy accelerates wound healing by facilitating sterilization, angiogenesis, and collagen deposition. This work provides distinct options to develop doping-engineered ultrathin nanosheets with augmented piezo-chemocatalytic activity for postoperative management of cutaneous melanoma.

Causal relationship between sex hormones and cutaneous melanoma: a two-sample Mendelian randomized study

This study aimed to elucidate the genetic aspects of the relationship between sex hormones and cutaneous melanoma risk, providing valuable insights into this complex association. In this study, we used estradiol, bioavailable testosterone, sex hormone-binding globulin, and total testosterone as the exposure and melanoma as the outcome for two-sample Mendelian randomization analysis. In this study, a random-effects inverse-variance weighting (IVW) model was used as the main analysis model, and the corresponding weighted median, simple mode, weighted mode, and Mendelian randomization‒Egger methods were used as supplementary methods. We assessed both heterogeneity and horizontal pleiotropy in our study, scrutinizing whether the analysis results were affected by any individual single nucleotide polymorphism. The random-effects IVW method indicated that estradiol [odds ratio (OR), 1.000; 95% confidence interval (CI), 0.998-1.003; P  = 0.658], bioavailable testosterone (OR = 1.001, 95% CI, 0.999-1.003; P  = 0.294), sex hormone-binding globulin (IVW: OR, 1.000; 95% CI, 0.998-1.003; P  = 0.658), and total testosterone (IVW: OR, 1.002; 95% CI, 0.999-1.005; P  = 0.135) were not genetically linked to cutaneous melanoma. No analyses exhibited heterogeneity, horizontal pleiotropy, or deviations. We were unable to find genetic evidence for a causal relationship between sex hormones and the occurrence of cutaneous melanoma in this study. These results are limited by sample size and population, so the causal relationship between sex hormones and cutaneous melanoma needs to be further studied.

Oncogenic and telomeric G-quadruplexes: Targets for porphyrin-triphenylphosphonium conjugates

DNA chains with sequential guanine (G) repeats can lead to the formation of G-quadruplexes (G4), which are found in functional DNA and RNA regions like telomeres and oncogene promoters. The development of molecules with adequate structural features to selectively stabilize G4 structures can counteract cell immortality, highly described for cancer cells, and also downregulate transcription events underlying cell apoptosis and/or senescence processes. We describe here, the efficiency of four highly charged porphyrins-phosphonium conjugates to act as G4 stabilizing agents. The spectrophotometric results allowed to select the conjugates P2-PPh3 and P3-PPh3 as the most promising ones to stabilize selectively G4 structures. Molecular dynamics simulation experiments were performed and support the preferential binding of P2-PPh3 namely to MYC and of P3-PPh3 to KRAS. The ability of both ligands to block the activity of Taq polymerase was confirmed and also their higher cytotoxicity against the two melanoma cell lines A375 and SK-MEL-28 than to immortalized skin keratinocytes. Both ligands present efficient cellular uptake, nuclear co-localization and high ability to generate 1O2 namely when interacting with G4 structure. The obtained data points the synthesized porphyrins as promising ligands to be used in a dual approach that can combine G4 stabilization and Photodynamic therapy (PDT).

Rational design of solid lipid-polymer hybrid nanoparticles: An innovative glycoalkaloids-carrier with potential for topical melanoma treatment

Despite the promising potential of Solanum plant glycoalkaloids in combating skin cancer, their clinical trials have been halted due to dose-dependent toxicity and poor water solubility. In this study, we present a rational approach to address these limitations and ensure colloidal stability of the nanoformulation over time by designing solid lipid-polymer hybrid nanoparticles (SLPH). Leveraging the biocompatible and cationic properties of polyaspartamides, we employed a new polyaspartamide derivative (P1) as a raw material for this class of nanostructures. Subsequently, we prepared SLPH through a one-step process involving hot-melt emulsification followed by ultrasonication. The physicochemical properties of the SLPH were thoroughly characterized using dynamic light scattering (DLS), ζ-potential analysis, nanoparticle tracking analysis (NTA), differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FT-IR), and transmission electron microscopy (TEM). The optimized formulation exhibited long-term stability over six months under low temperatures, maintaining a particle size around 200 nm, a polydispersity index (PdI) lower than 0.2, and a ζ-potential between +35-40 mV. Furthermore, we evaluated the cytotoxic effect of the SLPH against human cutaneous melanoma cells (SK-MEL-28) compared to human foreskin fibroblast cells (HFF-1). Encapsulation of glycoalkaloids into the nanoparticles (SLPH-GE) resulted in a two-fold greater selective cytotoxic profile for melanoma cells than glycoalkaloids-free (GE). The nanoparticles disrupted the stratum corneum barrier with a penetration depth of approximately 77 μm. These findings underscore the potential of the developed nanosystem as an effective glycoalkaloid carrier with suitable colloidal and biological properties for further studies in topical treatment strategies for cutaneous melanoma.

Circular RNA-encoded oncogenic PIAS1 variant blocks immunogenic ferroptosis by modulating the balance between SUMOylation and phosphorylation of STAT1

BACKGROUND

The clinical response rate to immune checkpoint blockade (ICB) therapy in melanoma remains low, despite its widespread use. Circular non-coding RNAs (circRNAs) are known to play a crucial role in cancer progression and may be a key factor limiting the effectiveness of ICB treatment.

METHODS

The circRNAs that were downregulated after coadministration compared with single administration of PD-1 inhibitor administration were identified through RNA-seq and Ribo-seq, and thus the circPIAS1 (mmu_circ_0015773 in mouse, has_circ_0008378 in human) with high protein coding potential was revealed. Fluorescence in situ hybridization (FISH) assays were conducted to determine the localization of circPIAS1 in human and mouse melanoma cells, as well as its presence in tumor and adjacent tissues of patients. Validation through dual-luciferase reporter assay and LC-MS/MS confirmed the ability of circPIAS1 to encode a novel 108 amino acid polypeptide (circPIAS1-108aa). Specific antisense oligonucleotides (ASOs) targeting the junction site of circPIAS1 were developed to reduce its intracellular levels. Proliferation changes in melanoma cells were assessed using CCK8, EdU, and colony formation assays. The impact of circPIAS1-108aa on the ferroptosis process of melanoma cells was studied through GSH, MDA, and C11-BODIPY staining assays. Western Blot, Immunoprecipitation (IP), and Immunoprecipitation-Mass Spectrometry (IP-MS) techniques were employed to investigate the impact of circPIAS1-108aa on the P-STAT1/SLC7A11/GPX4 signaling pathway, as well as its influence on the balance between STAT1 SUMOylation and phosphorylation. Additionally, a melanoma subcutaneous transplanted tumor mouse model was utilized to examine the combined effect of reducing circPIAS1 levels alongside PD-1 inhibitor.

RESULTS

Compared with the group treated with PD-1 inhibitor alone, circPIAS1 was significantly down-regulated in the coadministration group and demonstrated higher protein coding potential. CircPIAS1, primarily localized in the nucleus, was notably upregulated in tumor tissues compared to adjacent tissues, where it plays a crucial role in promoting cancer cell proliferation. This circRNA can encode a unique polypeptide consisting of 108 amino acids, through which it exerts its cancer-promoting function and impedes the effectiveness of ICB therapy. Mechanistically, circPIAS1-108aa hinders STAT1 phosphorylation by recruiting SUMO E3 ligase Ranbp2 to enhance STAT1 SUMOylation, thereby reactivating the transduction of the SLC7A11/GPX4 signaling pathway and restricting the immunogenic ferroptosis induced by IFNγ. Furthermore, the combination of ASO-circPIAS1 with PD-1 inhibitor effectively inhibits melanoma growth and significantly enhances the efficacy of immune drugs in vivo.

CONCLUSIONS

Our study uncovers a novel mechanism regarding immune evasion in melanoma driven by a unique 108aa peptide encoded by circPIAS1 in melanoma that dramatically hinders immunogenic ferroptosis triggered by ICB therapy via modulating the balance between SUMOylation and phosphorylation of STAT1. This work reveals circPIAS1-108aa as a critical factor limiting the immunotherapeutic effects in melanoma and propose a promising strategy for improving ICB treatment outcomes.

ELK4 targets CHMP6 to inhibit ferroptosis and enhance malignant properties of skin cutaneous melanoma cells

Ferroptosis, a key factor in tumor progression, is poorly understood at the molecular level. This study investigates how ELK4 and CHMP6 regulate skin cutaneous melanoma (SKCM) cell proliferation and ferroptosis. Analysis of TCGA data reveals high expression of ELK4 and CHMP6 in SKCM. Overexpression of ELK4 or CHMP6 enhances cell proliferation, invasion, and migration while reducing ROS and Fe2 + levels. It also increases GPX4 and xCT expression and decreases ACSL4 levels in SKCM cells. The opposite effects are observed with ELK4 or CHMP6 knockdown. ELK4 binds to the CHMP6 promoter, promoting CHMP6 transcription. Knockdown of CHMP6 reverses the oncogenic effects of ELK4 overexpression. In conclusion, ELK4 enhances proliferation, invasion, and migration while inhibiting ferroptosis in SKCM cells by upregulating CHMP6 transcription. This study sheds light on the intricate mechanisms involved in SKCM progression and identifies potential therapeutic targets in melanoma treatment.

Advances in the management of regionally metastatic melanoma

Despite numerous developments in systemic therapy, the prognosis for patients with locoregionally advanced melanoma remains poor. By delivering therapy directly to the targeted area via intralesional injections or intra-arterial isolated infusions, systemic side effects are minimized and oncolytic agents are delivered more directly and effectively to the melanoma. There has been significant progress in recent years with intralesional agents such as Talimogene laherparepvec (T-VEC), PV-10 and TAVOkinase/electrocorporation as well as advances in infusional therapies such as percutaneous hepatic perfusion (PHP) for hepatic metastasis of ocular melanoma. This review evaluates advances in intralesional and infusional therapies for melanoma while limiting discussion to those therapies currently approved and on trial.

Strongly ROS-Correlated, Time-Dependent, and Selective Antiproliferative Effects of Synthesized Nano Vesicles on BRAF Mutant Melanoma Cells and Their Hyaluronic Acid-Based Hydrogel Formulation

Cutaneous metastatic melanoma (CMM) is the most aggressive form of skin cancer with a poor prognosis. Drug-induced secondary tumorigenesis and the emergency of drug resistance worsen an already worrying scenario, thus rendering urgent the development of new treatments not dealing with mutable cellular processes. Triphenyl phosphonium salts (TPPSs), in addiction to acting as cytoplasmic membrane disruptors, are reported to be mitochondria-targeting compounds, exerting anticancer effects mainly by damaging their membranes and causing depolarization, impairing mitochondria functions and their DNA, triggering oxidative stress (OS), and priming primarily apoptotic cell death. TPP-based bola amphiphiles are capable of self-forming nanoparticles (NPs) with enhanced biological properties, as commonly observed for nanomaterials. Already employed in several other biomedical applications, the per se selective potent antibacterial effects of a TPP bola amphiphile have only recently been demonstrated on 50 multidrug resistant (MDR) clinical superbugs, as well as its exceptional and selective anticancer properties on sensitive and MDR neuroblastoma cells. Here, aiming at finding new molecules possibly developable as new treatments for counteracting CMM, the effects of this TPP-based bola amphiphile (BPPB) have been investigated against two BRAF mutants CMM cell lines (MeOV and MeTRAV) with excellent results (even IC50 = 49 nM on MeOV after 72 h treatment). With these findings and considering the low cytotoxicity of BPPB against different mammalian non-tumoral cell lines and red blood cells (RBCs, selectivity indexes up to 299 on MeOV after 72 h treatment), the possible future development of BPPB as topical treatment for CMM lesions was presumed. With this aim, a biodegradable hyaluronic acid (HA)-based hydrogel formulation (HA-BPPB-HG) was prepared without using any potentially toxic crosslinking agents simply by dispersing suitable amounts of the two ingredients in water and sonicating under gentle heating. HA-BPPB-HA was completely characterized, with promising outcomes such as high swelling capability, high porosity, and viscous elastic rheological behavior.

The ZDHHC13/ZDHHC17 subfamily: From biological functions to therapeutic targets of diseases

The ZDHHC13/ZDHHC17 subfamily belongs to the zinc finger DHHC-domain containing (ZDHHC) family, including ZDHHC13 and ZDHHC17. Recent studies have shown that the ZDHHC13/ZDHHC17 subfamily is involved in various pathological and physiological processes, including S-palmitoylation, Mg2+ transport, and CALCOCO1-mediated Golgiphagy. Moreover, the ZDHHC13/ZDHHC17 subfamily plays a crucial role in the occurrence and development of many diseases, including Huntington disease (HD), osteoporosis, atopic dermatitis, diabetes, and cancer. In the present review, we describe the distribution, structure, and post-translational modifications (PTMs) of the ZDHHC13/ZDHHC17 subfamily. Moreover, we effectively summarize the biological functions and associated diseases of this subfamily. Given the pleiotropy of the ZDHHC13/ZDHHC17 subfamily, it is imperative to conduct further research on its members to comprehend the pertinent pathophysiological mechanisms and to devise tactics for managing and controlling various diseases.

Machine learning-based identification of an immunotherapy-related signature to enhance outcomes and immunotherapy responses in melanoma

Background

Immunotherapy has revolutionized skin cutaneous melanoma treatment, but response variability due to tumor heterogeneity necessitates robust biomarkers for predicting immunotherapy response.

Methods

We used weighted gene co-expression network analysis (WGCNA), consensus clustering, and 10 machine learning algorithms to develop the immunotherapy-related gene model (ITRGM) signature. Multi-omics analyses included bulk and single-cell RNA sequencing of melanoma patients, mouse bulk RNA sequencing, and pathology sections of melanoma patients.

Results

We identified 66 consensus immunotherapy prognostic genes (CITPGs) using WGCNA and differentially expressed genes (DEGs) from two melanoma cohorts. The CITPG-high group showed better prognosis and enriched immune activities. DEGs between CITPG-high and CITPG-low groups in the TCGA-SKCM cohort were analyzed in three additional melanoma cohorts using univariate Cox regression, resulting in 44 consensus genes. Using 101 machine learning algorithm combinations, we constructed the ITRGM signature based on seven model genes. The ITRGM outperformed 37 published signatures in predicting immunotherapy prognosis across the training cohort, three testing cohorts, and a meta-cohort. It effectively stratified patients into high-risk or low-risk groups for immunotherapy response. The low-risk group, with high levels of model genes, correlated with increased immune characteristics such as tumor mutation burden and immune cell infiltration, indicating immune-hot tumors with a better prognosis. The ITRGM's relationship with the tumor immune microenvironment was further validated in our experiments using pathology sections with GBP5, an important model gene, and CD8 IHC analysis. The ITRGM also predicted better immunotherapy response in eight cohorts, including urothelial carcinoma and stomach adenocarcinoma, indicating broad applicability.

Conclusions

The ITRGM signature is a stable and robust predictor for stratifying melanoma patients into 'immune-hot' and 'immune-cold' tumors, enhancing prognosis and response to immunotherapy.

Genetically predicted metabolites mediate the association between lipidome and malignant melanoma of skin

Objective

To investigate the causal relationship between lipidome and malignant melanoma of skin (MMOS), while identifying and quantifying the role of metabolites as potential mediators.

Methods

A two-sample Mendelian randomization (MR) analysis of lipid species (n=7174) and MMOS was performed using pooled data from genome-wide association studies (GWAS). In addition, we quantified the proportion of metabolite-mediated lipidome effects on MMOS by two-step MR.

Results

This study identified potential causal relationships between 11 lipids and MMOS, and 40 metabolites and MMOS, respectively. Phosphatidylethanolamine (18:0_18:2) levels mined from 179 lipids by MR Analysis increased the risk of MMOS (OR: 1.962; 95%CI:1.298,2.964; P=0.001). There is no strong evidence for a relationship between genetically predicted MMOS and phosphatidylethanolamine (18:0_18:2) levels (P=0.628). The proportion of gene predictions for phosphatidylethanolamine (18:0_18:2) levels mediated by 1-stearoyl-(glycosylphosphatidylinositol) GPI (18:0) levels was 12.40%.

Conclusion

This study identifies 1-stearoyl-GPI (18:0) levels as a potential mediator that may mediate the causal relationship between phosphatidylethanolamine (18:0_18:2) levels and MMOS, This provides direction for the investigation of MMOS, but further research of other possible potential mediators is still needed.

Topical Delivery of Dual Loaded Nano-Transfersomes Mediated Chemo-Photodynamic Therapy against Melanoma via Inducing Cell Cycle Arrest and Apoptosis

Melanoma is a malignant skin cancer associated with high mortality rates and drug resistance, posing a significant threat to human health. The combination of chemotherapy and photodynamic therapy (PDT) represents a promising strategy to enhance antitumor efficacy through synergistic anti-cancer effects. Topical delivery of chemotherapeutic drugs and photosensitizers (PS) offers a non-invasive and safe way to treat melanoma. However, the effectiveness of these treatments is often hindered by challenges such as limited skin permeability and instability of the PS. In this study, transfersomes (TFS) were designed to facilitate transdermal delivery of the chemotherapeutic drug 5-Fluorouracil (5-FU) and the PS Imperatorin (IMP) for combined chemo-photodynamic therapy for melanoma. The cytotoxic and phototoxic effects of TFS-mediated PDT (TFS-UVA) were investigated in A375 cells and nude mice. The study also demonstrated that TFS-UVA generated intracellular ROS, induced G2/ M phase cell cycle arrest, and promoted cell apoptosis. In conclusion, this study indicated that 5-FU/ IMP-TFS serves as an effective transdermal therapeutic strategy for chemo-PDT in treating melanoma.

TICRR Overexpression Enhances Disease Aggressiveness and Immune Infiltration of Cutaneous Melanoma

Objective

To investigate the role of the TopBP1 interacting checkpoint and replication regulator (TICRR) in cutaneous melanoma (CM) as a prognostic biomarker and therapeutic target.

Methods

TICRR expression in tumour samples was explored using the TCGA and the GTEx database. The Kaplan-Meier survival curve, nomogram model and risk score curve were established to evaluate the prognostic role of TICRR in CM. Tissue samples of CM patients were obtained to validate the TICRR expression further. Several experiments in vitro were conducted to investigate the effect of TICRR upon CM aggressiveness and to explore underlying mechanisms.

Results

TICRR was overexpressed in CM tissue and was correlated with poor prognosis of CM patients. The knockdown of TICRR decreased the proliferation, migration, and invasion of CM cells, whereas overexpression produced the opposite effect. Furthermore, TICRR suppression substantially attenuated the activation of PI3K/AKT/mTOR signalling, while the PI3K/AKT inhibitor LY294002 could partially reverse the aggressiveness-enhancing effect induced by TICRR overexpression. It was further confirmed that TICRR was closely related to immune cell infiltration activities by using immune infiltration and immunofluorescence analysis.

Conclusion

TICRR overexpression may enhance CM aggressiveness by activating the PI3K/Akt/mTOR pathway and promoting immune infiltration. TICRR was verified as a potential prognostic biomarker and therapeutic target for CM.

Preclinical ImmunoPET Imaging Using a Zr-89-Labeled Anti-CD146 Monoclonal Antibody for Diagnosis of Melanoma

The aim of this study was to evaluate the preclinical efficacy of [89Zr]Zr-DFO-Ab253 as a novel positron emission tomography (PET) tracer for CD146-positive malignant melanoma imaging. Considering the high expression of CD146 in malignant melanoma, this study investigated the effect of different CD146 expression levels on the tumor uptake of [89Zr]Zr-DFO-Ab253. CD146 selectivity was investigated by using the CD146-positive human melanoma cell A375 and the CD146-negative human alveolar epithelial cell A549. The cell uptake of [89Zr]Zr-DFO-Ab253 tracers was investigated, and receptor-binding affinities were measured by radioactive enzyme-linked immunosorbent assay. Biodistribution studies and micro-PET imaging of the radiotracers were performed on mice bearing A375 and A549 xenografts under baseline and blocking conditions. An immunohistochemical test was performed using A375 and A549 tissue sections for CD146 expression level analysis. [89Zr]Zr-DFO-Ab253 was obtained with a high radiochemical yield (87.86 ± 4.66%) and a satisfactory radiochemical purity (>98.0%). The specificity and affinity of [89Zr]Zr-DFO-Ab253 were confirmed in melanoma A375 cells and in vivo PET imaging of A375 tumor models. [89Zr]Zr-DFO-IgG and A549 lung tumors were prepared as control radiotracers and negative models to verify the specificity of [89Zr]Zr-DFO-Ab253 on CD146. [89Zr]Zr-DFO-Ab253 has a Kd of 4.01 ± 0.50 nM. PET imaging and biodistribution showed a higher uptake of [89Zr]Zr-DFO-Ab253 in A375 melanomas than that in A549 tumors (42.1 ± 4.04% vs 7.87 ± 1.30% ID/g at 120 h, P < 0.05). A low tumor uptake of [89Zr]Zr-DFO-IgG was observed with uptakes of 1.91 ± 0.41 and 2.80 ± 0.14 ID%/g when blocked at 120 h. The radiation-absorbed dose was calculated to be 0.13 mSv/MBq. This study demonstrates the synthesis and preclinical evaluation of [89Zr]Zr-DFO-Ab253 and indicates that the novel tracer has promising applications in malignant melanoma-specific PET imaging because of its high uptake and long-time retention in malignant melanoma. It also provides feasibility for the development of integrated molecular probes for diagnosis and treatment based on the CD146 target.

Circulating tumor DNA-based assessment of molecular residual disease in non-metastatic melanoma

In patients with resected non-metastatic melanoma, the liquid biopsy for the assessment of molecular residual disease (MRD) by circulating tumour DNA (ctDNA) represents a promising tool to stratify the risk and to monitor tumour evolution. However, its validation requires the demonstration of analytical validity, clinical validity and utility. Indeed, the development of sensitive and specific assays can optimize prognostication and eventually help clinicians to modulate adjuvant treatments, in order to improve clinical outcomes. Data about ctDNA-guided prognosis stratification is emerging, but clinical trials assessing ctDNA-guided therapeutic decisions are still ongoing. This review aims to depict the role of ctDNA-based MRD assessment in patients with non-metastatic melanoma and to provide a roadmap to face challenges for its introduction into clinical practice.

Extract of Araçá-Boi and Its Major Phenolic Compound, Trans-Cinnamic Acid, Reduce Viability and Inhibit Migration of Human Metastatic Melanoma Cells

Cutaneous melanoma is an aggressive type of skin cancer that is recognized for its high metastatic potential and the challenges it presents in its treatment. There has been increasing interest in plant extracts and their potential applications in melanoma. The present study aimed to investigate the content of individual phenolic compounds in araçá-boi extract, evaluate their antioxidant activity, and explore their effects on cell viability, migration properties, oxidative stress levels, and protein expression in the human metastatic melanoma cell line SK-MEL-28. HPLC-DAD analysis identified 11 phenolic compounds in the araçá-boi extract. Trans-cinnamic acid was the main phenolic compound identified; therefore, it was used alone to verify its contribution to antitumor activities. SK-MEL-28 melanoma cells were treated for 24 h with different concentrations of araçá-boi extract and trans-cinnamic acid (200, 400, 600, 800, and 1600 µg/mL). Both the araçá-boi extract and trans-cinnamic acid reduced cell viability, cell migration, and oxidative stress in melanoma cells. Additionally, they modulate proteins involved in apoptosis and inflammation. These findings suggest the therapeutic potential of araçá-boi extract and its phenolic compounds in the context of melanoma, especially in strategies focused on preventing metastasis. Additional studies, such as the analysis of specific signaling pathways, would be valuable in confirming and expanding these observations.

Single-cell RNA sequencing reveals melanoma cell state-dependent heterogeneity of response to MAPK inhibitors

BACKGROUND

Melanoma is a heterogeneous cancer influenced by the plasticity of melanoma cells and their dynamic adaptations to microenvironmental cues. Melanoma cells transition between well-defined transcriptional cell states that impact treatment response and resistance.

METHODS

In this study, we applied single-cell RNA sequencing to interrogate the molecular features of immunotherapy-naive and immunotherapy-resistant melanoma tumours in response to ex vivo BRAF/MEK inhibitor treatment.

FINDINGS

We confirm the presence of four distinct melanoma cell states - melanocytic, transitory, neural-crest like and undifferentiated, and identify enrichment of neural crest-like and undifferentiated melanoma cells in immunotherapy-resistant tumours. Furthermore, we introduce an integrated computational approach to identify subsets of responding and nonresponding melanoma cells within the transcriptional cell states.

INTERPRETATION

Nonresponding melanoma cells are identified in all transcriptional cell states and are predisposed to BRAF/MEK inhibitor resistance due to pro-inflammatory IL6 and TNFɑ signalling. Our study provides a framework to study treatment response within distinct melanoma cell states and indicate that tumour-intrinsic pro-inflammatory signalling contributes to BRAF/MEK inhibitor resistance.

FUNDING

This work was supported by Macquarie University, Melanoma Institute Australia, and the National Health and Medical Research Council of Australia (NHMRC; grant 2012860, 2028055).

Brightfield Multiplex Immunohistochemistry Assay for PD-L1 Evaluation in Challenging Melanoma Samples

Targeting the PD1/PD-L1 immune checkpoint pathway has rapidly become a therapeutic strategy for melanoma patients. Indeed, the quantification of PD-L1 expression by immunohistochemistry (IHC) in melanoma samples is already required, in some contexts, to allow access to anti-PD-1/PD-L1 immunotherapy. Despite a rising demand for PD-L1 testing, paralleling increasing cumulative experience in its assessment and quantification, it is fair to recognize that PD-L1 evaluation in melanoma samples still presents some critical issues. The aim of this technical report is to develop and validate a multiplex double staining protocol for PD-L1/SOX10 in Ventana Benchmark Ultra for routine practice. Our results show that double labeling provides the necessary tools to identify PD-L1 + melanoma cells clearly. The simultaneous visualization of 2 different proteins targets allows the topographical relationship between the 2 labeling to be evaluated within the context of the tissue morphology. Future studies are needed to test this technique's real-world applicability and effectiveness in implementing interpathologist agreement.

Lipo/TK-CDN/TPP/Y6 nanoparticles inhibit cutaneous melanoma formation

Stimulation of the innate immune stimulator of interferon genes (STING) pathway has been shown to boost anti-tumour immunity. Nevertheless, the systemic delivery of STING agonists to the tumour presents challenges. Therefore, we designed a cyclic dinucleotide (CDN)-based drug delivery system (DDS) combined photothermal therapy (PTT)/photodynamic therapy (PDT)/immunotherapy for cutaneous melanoma. We coencapsulated a reactive oxygen species (ROS)-responsive prodrug thioketone-linked CDN (TK-CDN), and photoresponsive agents chlorin E6 (Y6) within mitochondria-targeting reagent triphenylphosphonium (TPP)-modified liposomes (Lipo/TK-CDN/TPP/Y6). Lipo/TK-CDN/TPP/Y6 exhibited a photothermal effect similar to Y6, along with a superior cellular uptake rate. Upon endocytosis by B16F10 cells, Lipo/TK-CDN/TPP/Y6 generated large amounts of ROS under laser irradiation for PDT. Mice bearing B16F10 tumours were intravenously injected with Lipo/TK-CDN/TPP/Y6 and exposed to irradiation, resulting in a substantial inhibition of tumour growth. Exploration of the mechanism of anti-tumour action showed that Lipo/TK-CDN/TPP/Y6 had a stronger stimulation of STING activation and anti-tumour immune cell infiltration compared to other groups. Hence, the Lipo/TK-CDN/TPP/Y6 nanoparticles offer great potential as a DDS for targeted and on-demand drug release at tumour sites. These nanoparticles exhibit promise as a candidate for precise and controllable combination therapy in the treatment of tumours.

Berberine sensitizes immune checkpoint blockade therapy in melanoma by NQO1 inhibition and ROS activation

Unprecedented progress in immune checkpoint blockade (ICB) therapy has been made in cancer treatment. However, the response to ICB therapy is limited to a small subset of patients. The development of ICB sensitizers to improve cancer immunotherapy outcomes is urgently needed. Berberine (BBR), a well-known phytochemical compound isolated from many kinds of medicinal plants such as Berberis aristata, Coptis chinensis, and Phellondendron chinense Schneid, has shown the ability to inhibit the proliferation, invasion and metastasis of cancer cells. In this study, we investigated whether BBR can enhance the therapeutic benefit of ICB for melanoma, and explored the underlying mechanisms involved. The results showed that BBR could sensitize ICB to inhibit tumor growth and increased the survival rate of mice. Moreover, BBR stimulated intracellular ROS production partially by inhibiting NQO1 activity, which induced immunogenic cell death (ICD) in melanoma, elevated the levels of damage-associated molecular patterns (DAMPs), and subsequently activated DC cells and CD8 + T cells in vitro and in vivo. In conclusion, BBR is a novel ICD inducer. BBR could enhance the therapeutic benefit of ICB for melanoma. These effects were partially mediated through the inhibition of NQO1 and ROS activation.

A Mendelian randomization study of genetic liability to cutaneous melanoma and sunburns

Background

Some studies have reported that sunburns and cutaneous melanoma (CM) risk is increasing, but a clear causal link has yet to be established.

Methods

This current study conducted a two-sample Mendelian randomization (MR) approach to clarify the association and causality between sunburn history and CM using large-scale genome-wide association study data.

Results

The inverse-variance weighted method result showed that sunburn might be associated with the risk of CM increasing (p = 2.21 × 10-23, OR = 1.034, 95% CI= 1.027-1.041), causally. The MR-Egger regression, weighted median method, simple mode method, and weighted mode method results showed similar results.

Conclusion

This study offers evidence of sunburn history and increased risk of CM, and it shows that there might be common genetic basics regarding sunburns and CM susceptibility in Caucasian, European, or British ethnic groups.

Oxidative State in Cutaneous Melanoma Progression: A Question of Balance

Reactive oxygen species (ROS) are highly bioactive molecules involved not only in tissue physiology but also in the development of different human conditions, including premature aging, cardiovascular pathologies, neurological and neurodegenerative disorders, inflammatory diseases, and cancer. Among the different human tumors, cutaneous melanoma, the most aggressive and lethal form of skin cancer, is undoubtedly one of the most well-known "ROS-driven tumor", of which one of the main causes is represented by ultraviolet (UV) rays' exposure. Although the role of excessive ROS production in melanoma development in pro-tumorigenic cell fate is now well established, little is known about its contribution to the progression of the melanoma metastatic process. Increasing evidence suggests a dual role of ROS in melanoma progression: excessive ROS production may enhance cellular growth and promote therapeutic resistance, but at the same time, it can also have cytotoxic effects on cancer cells, inducing their apoptosis. In this context, the aim of the present work was to focus on the relationship between cell redox state and the signaling pathways directly involved in the metastatic processes. In addition, oxidative or antioxidant therapeutic strategies for metastatic melanoma were also reviewed and discussed.

Dammarane-Type 3,4-seco-Triterpenoid from Silver Birch (Betula pendula Roth) Buds Induces Melanoma Cell Death by Promotion of Apoptosis and Autophagy

Despite unquestionable advances in therapy, melanoma is still characterized by a high mortality rate. For years, high expectations have been raised by compounds of natural origin as a component of pharmacotherapy, particularly by triterpenes found in the bark of birch trees. In this study, 3,4-seco-dammara-4(29),20(21),24(25)-trien-3-oic acid (SDT) was isolated from buds of silver birch and its mechanisms of cell death induction, including apoptosis and autophagy, were determined. Cytotoxicity of SDT was evaluated by the cell viability test and clonogenic assay, whereas induction of apoptosis and autophagy was determined by annexin V staining and Western blot. The results revealed dose- and time-dependent reductions in viability of melanoma cells. Treatment of cells for 48 h led to an increase in the percentage of annexin V-positive cells, activation of caspase-8, caspase-9, and caspase-3, and cleavage of PARP, confirming apoptosis. Simultaneously, it was found that SDT increased the level of autophagy marker LC3-II and initiator of autophagy beclin-1. Pretreatment of cells with caspase-3 inhibitor or autophagy inhibitor significantly reduced the cytotoxicity of SDT and revealed that both apoptosis and autophagy contribute to a decrease in cell viability. These findings suggest that 3,4-seco-dammaranes may become a promising group of natural compounds for searching for anti-melanoma agents.

The possible and intriguing relationship between bullous pemphigoid and melanoma: speculations on significance and clinical relevance

Bullous pemphigoid (BP) is the most common autoimmune bullous disease: it most commonly affects individuals over 70 years old and impacts severely on their quality of life. BP represents a paradigm for an organ-specific autoimmune disease and is characterized by circulating IgG autoantibodies to hemidesmosomal components: BP180 and BP230. While the crucial role of these autoantibodies in triggering BP inflammatory cascade is fully acknowledged, many ancillary etiological mechanisms need to be elucidated yet. Cutaneous melanoma is due to a malignant transformation of skin melanocytes, that produce and distribute pigments to surrounding keratinocytes. Melanoma is the most fatal skin cancer because of its increasing incidence and its propensity to metastasize. Several data such as: i) reported cases of concomitant melanoma and BP; ii) results from association studies; iii) BP onset following immune check-point inhibitors therapy; iv) expression of BP antigens in transformed melanocytes; and vi) circulating autoantibodies to BP antigens in melanoma patients suggest an intriguing, although unproven, possible association between melanoma and BP. However, a possible causative link is still debated and the putative pathogenetic mechanism underlying this association is unclear. This review aims to describe and discuss the possible relationship between BP and melanoma and give an overview of the speculations for or against this association. Of note, if demonstrated, this association could unwrap considerations of clinical relevance that represent new research frontiers.

Advancements in melanoma immunotherapy: the emergence of Extracellular Vesicle Vaccines

Malignant melanoma represents a particularly aggressive type of skin cancer, originating from the pathological transformation of melanocytes. While conventional interventions such as surgical resection, chemotherapy, and radiation therapy are available, their non-specificity and collateral damage to normal cells has shifted the focus towards immunotherapy as a notable approach. Extracellular vesicles (EVs) are naturally occurring transporters, and are capable of delivering tumor-specific antigens and directly engaging in the immune response. Multiple types of EVs have emerged as promising platforms for melanoma vaccination. The effectiveness of EV-based melanoma vaccines manifests their ability to potentiate the immune response, particularly by activating dendritic cells (DCs) and CD8+ T lymphocytes, through engineering a synergy of antigen presentation and targeted delivery. Here, this review mainly focuses on the construction strategies for EV vaccines from various sources, their effects, and immunological mechanisms in treating melanoma, as well as the shortcomings and future perspectives in this field. These findings will provide novel insights into the innovative exploitation of EV-based vaccines for melanoma immune therapy.

Terphenyllin induces CASP3-dependent apoptosis and pyroptosis in A375 cells through upregulation of p53

BACKGROUND

Melanoma, one of the most lethal forms of skin cancer, has the potential to develop in any area where melanocytes are present. Currently, postoperative recurrence due to the emergence of systemic drug resistance represents a significant challenge in the treatment of melanoma. In this study, terphenyllin (TER), a distinctive inhibitory impact on melanoma cells was identified from the natural p-terphenyl metabolite. This study aimed to elucidate the intrinsic mechanism of this inhibitory effect, which may facilitate the discovery of novel chemotherapeutic agents.

METHODS

A transcriptome sequencing and metabolomic analysis of TER-treated A375 cells was conducted to identify potential pathways of action. The key proteins were knocked out and backfilled using CRISPR-Cas9 technology and molecular cloning. Subsequently, the results of cytosolic viability, LDH release, immunofluorescence and flow cytometry were employed to demonstrate the cell death status of the drug-treated cells.

RESULTS

The p53 signalling pathway was markedly upregulated following TER treatment, leading to the activation of CASP3 via the intrinsic apoptotic pathway. The activated CASP3 initiated apoptosis, while simultaneously continuing to cleave the GSDME, thereby triggering pyroptosis. The knockout of p53, a key protein situated upstream of this pathway, resulted in a significant rescue of TER-induced cell death, as well as an alleviation of the decrease in cell viability. However, the knockout of key proteins situated downstream of the pathway (CASP3 and GSDME) did not result in a rescue of TER-induced cell death, but rather a transformation of the cells from apoptosis and pyroptosis.

CONCLUSIONS

The induction of apoptosis and pyroptosis in A375 cells by TER is mediated via the p53-BAX/FAS-CASP3-GSDME signalling pathway. This lays the foundation for TER as a potential anti-melanoma drug in the future. It should be noted that CASP3 and GSDME in this pathway solely regulate the mode of cell death, rather than determine whether cell death occurs. This distinction may prove valuable in future studies of apoptosis and pyroptosis.

Prognosis and immunotherapy in melanoma based on selenoprotein k-related signature

Selenium and selenoproteins are closely related to melanoma progression. However, it is unclear how SELENOK affects lipid metabolism, endoplasmic reticulum stress (ERS), immune cell infiltration, survival, and prognosis in melanoma patients. Transcriptome data from melanoma patients was used to investigate SELENOK levels and their effect on prognosis, followed by an investigation of SELENOK's effects on immune cell infiltration. Furthermore, a risk model based on ERS, lipid metabolism, and immune-related genes was constructed, and its utility in melanoma prognosis was evaluated. Finally, the drug sensitivity of the risk model was analyzed to provide a reference for melanoma therapy. The results showed that melanoma with a high SELENOK level had a greater degree of immune cell infiltration and a better prognosis. Additionally, SELENOK was found to regulate ERS, lipid metabolism, and immune cell infiltration in melanoma. The risk model based on SELENOK signature genes successfully predicted the prognosis of melanoma, and the low-risk group exhibited a favorable immunological microenvironment. Furthermore, high-risk patients with melanoma were candidates for chemotherapy with RAS pathway inhibitors, whereas low-risk patients were more susceptible to routinely used chemotherapy medicines. In summary, SELENOK was shown to regulate ERS, lipid metabolism, and immune cell infiltration in melanoma, and SELENOK was positively associated with the prognosis of melanoma. The risk model based on SELENOK signature genes was valuable for melanoma prognosis and therapy.

Transcriptional switches in melanoma T Cells: Facilitating polarizing into regulatory T cells

Melanoma is a malignant skin tumor with a high mortality rate. Regulatory T cells (Tregs) are immune cells with immunosuppressive roles, however, the precise mechanisms governing Treg involvement in melanoma remain enigmatic. Experimental findings unveiled different transcription factor switches between normal and tumor T cell, with heightened FOXP3 and BATF in the latter. These factors induced immunosuppressive molecules and Treg maintenance genes, polarizing tumor T cells into Tregs. Spatial transcriptomics illuminated the preferential settlement of Tregs at the melanoma periphery. Within this context, FOXP3 in Tregs facilitated direct enhancement of specific ligand gene expression, fostering communication with neighboring cells. Novel functional molecules bound to FOXP3 or BATF in Tregs, such as SPOCK2, SH2D2A, and ligand molecules ITGB2, LTA, CLEC2C, CLEC2D, were discovered, which had not been previously reported in melanoma Treg studies. Furthermore, we validated our findings in a large number of clinical samples and identified the Melanoma Treg-Specific Regulatory Tag Set (Mel TregS). ELISA analysis showed that the protein levels of Mel TregS in melanoma Tregs were higher than in normal Tregs. We then utilized SERS technology to measure the signal values of Mel TregS in exosome, and successfully discriminated between healthy individuals and melanoma patients, as well as early and late-stage patients. This approach significantly enhanced detection sensitivity. In sum, our research elucidated fresh insights into the mechanisms governing Treg self-maintenance and communication with surrounding cells in melanoma. We also introduced an innovative method for clinical disease monitoring through SERS technology.

31-GEP (DecisionDx): a review of clinical utility and performance in a Mayo Clinic cohort

BACKGROUND

Cutaneous melanoma (CM) is a significant health concern because of its high metastatic potential. Gene Expression Profile (GEP) testing, particularly the 31-GEP test (DecisionDx-Melanoma), has been increasingly used for risk stratification in CM patients. This study aimed to evaluate the clinical utility and performance of the 31-GEP test in a real-world setting.

METHODS

Patients with CM who underwent 31-GEP testing from August 2014 to August 2022 at our institution were identified through searches of electronic health records. The study analyzed the influence of 31-GEP testing on clinical decision-making related to sentinel lymph node biopsy (SLNB), medical oncology referral, and postdiagnosis surveillance. Kaplan-Meier curves and Cox proportional hazard models were used to elucidate the test's performance, focusing on relapse-free survival (RFS) and melanoma-specific survival (MSS).

RESULTS

The study included 65 CM patients. Dermatologists ordered more than 80% of 31-GEP tests. In 81.5% of cases, 31-GEP results did not alter standard clinical management. SLNB decisions were unaffected in 92% of patients with pre-SLNB 31-GEP results. Among patients with stage I-IIA melanoma, 25% of those with high-risk 31-GEP results were referred to medical oncology. Contrary to expectations, the rate of nodal metastasis was higher in low-risk than in high-risk 31-GEP cases. Survival analysis showed overlapping RFS and MSS curves between different 31-GEP classes, suggesting limited prognostic value.

CONCLUSIONS

The 31-GEP test has a limited impact on clinical management decisions and shows limited prognostic value.

Unveiling the Dynamic Interplay between Cancer Stem Cells and the Tumor Microenvironment in Melanoma: Implications for Novel Therapeutic Strategies

Cutaneous melanoma still represents a significant health burden worldwide, being responsible for the majority of skin cancer deaths. Key advances in therapeutic strategies have significantly improved patient outcomes; however, most patients experience drug resistance and tumor relapse. Cancer stem cells (CSCs) are a small subpopulation of cells in different tumors, including melanoma, endowed with distinctive capacities of self-renewal and differentiation into bulk tumor cells. Melanoma CSCs are characterized by the expression of specific biomarkers and intracellular pathways; moreover, they play a pivotal role in tumor onset, progression and drug resistance. In recent years, great efforts have been made to dissect the molecular mechanisms underlying the protumor activities of melanoma CSCs to provide the basis for novel CSC-targeted therapies. Herein, we highlight the intricate crosstalk between melanoma CSCs and bystander cells in the tumor microenvironment (TME), including immune cells, endothelial cells and cancer-associated fibroblasts (CAFs), and its role in melanoma progression. Specifically, we discuss the peculiar capacities of melanoma CSCs to escape the host immune surveillance, to recruit immunosuppressive cells and to educate immune cells toward an immunosuppressive and protumor phenotype. We also address currently investigated CSC-targeted strategies that could pave the way for new promising therapeutic approaches for melanoma care.

Current advance of nanotechnology in diagnosis and treatment for malignant tumors

Cancer remains a significant risk to human health. Nanomedicine is a new multidisciplinary field that is garnering a lot of interest and investigation. Nanomedicine shows great potential for cancer diagnosis and treatment. Specifically engineered nanoparticles can be employed as contrast agents in cancer diagnostics to enable high sensitivity and high-resolution tumor detection by imaging examinations. Novel approaches for tumor labeling and detection are also made possible by the use of nanoprobes and nanobiosensors. The achievement of targeted medication delivery in cancer therapy can be accomplished through the rational design and manufacture of nanodrug carriers. Nanoparticles have the capability to effectively transport medications or gene fragments to tumor tissues via passive or active targeting processes, thus enhancing treatment outcomes while minimizing harm to healthy tissues. Simultaneously, nanoparticles can be employed in the context of radiation sensitization and photothermal therapy to enhance the therapeutic efficacy of malignant tumors. This review presents a literature overview and summary of how nanotechnology is used in the diagnosis and treatment of malignant tumors. According to oncological diseases originating from different systems of the body and combining the pathophysiological features of cancers at different sites, we review the most recent developments in nanotechnology applications. Finally, we briefly discuss the prospects and challenges of nanotechnology in cancer.

Innate Immune Cells in Melanoma: Implications for Immunotherapy

The innate immune system, composed of neutrophils, basophils, eosinophils, myeloid-derived suppressor cells (MDSCs), macrophages, dendritic cells (DCs), mast cells (MCs), and innate lymphoid cells (ILCs), is the first line of defense. Growing evidence demonstrates the crucial role of innate immunity in tumor initiation and progression. Several studies support the idea that innate immunity, through the release of pro- and/or anti-inflammatory cytokines and tumor growth factors, plays a significant role in the pathogenesis, progression, and prognosis of cutaneous malignant melanoma (MM). Cutaneous melanoma is the most common skin cancer, with an incidence that rapidly increased in recent decades. Melanoma is a highly immunogenic tumor, due to its high mutational burden. The metastatic form retains a high mortality. The advent of immunotherapy revolutionized the therapeutic approach to this tumor and significantly ameliorated the patients' clinical outcome. In this review, we will recapitulate the multiple roles of innate immune cells in melanoma and the related implications for immunotherapy.

Predictors of survival in immunotherapy-based treatments in advanced melanoma: a meta-analysis

The introduction of immunotherapy-based strategies has significantly improved the prognosis for melanoma patients. Nevertheless, some patients still have dismal outcomes, emphasizing the significance of survival predictive indicators in immunotherapy-based approaches. We systematically searched randomized controlled clinical trials investigating dual immunotherapy or chemoimmunotherapy versus placebo or mono-immunotherapy or chemotherapy alone in advanced melanoma patients. R version 4.3.0. was employed to perform all analyses. A comprehensive analysis was conducted on a total of 13,809 patients with advanced melanoma from 19 randomized clinical trials. Immunotherapy-based strategies (alone or in combination) could significantly lengthen the overall survival(OS) and recurrence-free survival (RFS) compared with corresponding controls. Mono-immunotherapy improved RFS and OS in PD-L1 positive patients, in stage AJCC IIIC, and with 4 or more positive lymph nodes, compared with chemotherapy. Combined immunotherapy statistically improved RFS and OS in those aged < 65, with an Eastern Cooperative Oncology Group (ECOG) status of 0, and LDH ≤ ULN at baseline compared with single treatment alone. Our findings indicated that certain clinicopathological and molecular features could assist in choosing appropriate melanoma patients for immune-based treatments.

Exploring a specialized programmed-cell death patterns to predict the prognosis and sensitivity of immunotherapy in cutaneous melanoma via machine learning

The mortality and therapeutic failure in cutaneous melanoma (CM) are mainly caused by wide metastasis and chemotherapy resistance. Meanwhile, immunotherapy is considered a crucial therapy strategy for CM patients. However, the efficiency of currently available methods and biomarkers in predicting the response of immunotherapy and prognosis of CM is limited. Programmed cell death (PCD) plays a significant role in the occurrence, development, and therapy of various malignant tumors. In this research, we integrated fourteen types of PCD, multi-omics data from TCGA-SKCM and other cohorts in GEO, and clinical CM patients to develop our analysis. Based on significant PCD patterns, two PCD-related CM clusters with different prognosis, tumor microenvironment (TME), and response to immunotherapy were identified. Subsequently, seven PCD-related features, especially CD28, CYP1B1, JAK3, LAMP3, SFN, STAT4, and TRAF1, were utilized to establish the prognostic signature, namely cell death index (CDI). CDI accurately predicted the response to immunotherapy in both CM and other cancers. A nomogram with potential superior predictive ability was constructed, and potential drugs targeting CM patients with specific CDI have also been identified. Given all the above, a novel CDI gene signature was indicated to predict the prognosis and exploit precision therapeutic strategies of CM patients, providing unique opportunities for clinical intelligence and new management methods for the therapy of CM.

Targeting novel regulated cell death: Ferroptosis, pyroptosis and necroptosis in anti-PD-1/PD-L1 cancer immunotherapy

Chemotherapy, radiotherapy, and immunotherapy represent key tumour treatment strategies. Notably, immune checkpoint inhibitors (ICIs), particularly anti-programmed cell death 1 (PD1) and anti-programmed cell death ligand 1 (PD-L1), have shown clinical efficacy in clinical tumour immunotherapy. However, the limited effectiveness of ICIs is evident due to many cancers exhibiting poor responses to this treatment. An emerging avenue involves triggering non-apoptotic regulated cell death (RCD), a significant mechanism driving cancer cell death in diverse cancer treatments. Recent research demonstrates that combining RCD inducers with ICIs significantly enhances their antitumor efficacy across various cancer types. The use of anti-PD-1/PD-L1 immunotherapy activates CD8+ T cells, prompting the initiation of novel RCD forms, such as ferroptosis, pyroptosis, and necroptosis. However, the functions and mechanisms of non-apoptotic RCD in anti-PD1/PD-L1 therapy remain insufficiently explored. This review summarises the emerging roles of ferroptosis, pyroptosis, and necroptosis in anti-PD1/PD-L1 immunotherapy. It emphasises the synergy between nanomaterials and PD-1/PD-L1 inhibitors to induce non-apoptotic RCD in different cancer types. Furthermore, targeting cell death signalling pathways in combination with anti-PD1/PD-L1 therapies holds promise as a prospective immunotherapy strategy for tumour treatment.

Comprehensive analysis of single cell and bulk RNA sequencing reveals the heterogeneity of melanoma tumor microenvironment and predicts the response of immunotherapy

BACKGROUND

Tumor microenvironment (TME) heterogeneity is an important factor affecting the treatment response of immune checkpoint inhibitors (ICI). However, the TME heterogeneity of melanoma is still widely characterized.

METHODS

We downloaded the single-cell sequencing data sets of two melanoma patients from the GEO database, and used the "Scissor" algorithm and the "BayesPrism" algorithm to comprehensively analyze the characteristics of microenvironment cells based on single-cell and bulk RNA-seq data. The prediction model of immunotherapy response was constructed by machine learning and verified in three cohorts of GEO database.

RESULTS

We identified seven cell types. In the Scissor+ subtype cell population, the top three were T cells, B cells and melanoma cells. In the Scissor- subtype, there are more macrophages. By quantifying the characteristics of TME, significant differences in B cells between responders and non-responders were observed. The higher the proportion of B cells, the better the prognosis. At the same time, macrophages in the non-responsive group increased significantly. Finally, nine gene features for predicting ICI response were constructed, and their predictive performance was superior in three external validation groups.

CONCLUSION

Our study revealed the heterogeneity of melanoma TME and found a new predictive biomarker, which provided theoretical support and new insights for precise immunotherapy of melanoma patients.

Epigenetic Reprogramming Potentiates ICAM1 Antibody Drug Conjugates in Preclinical Models of Melanoma

Therapeutic benefits and underlying biomechanism(s) of antibody drug conjugates (ADC) in combination with other targeted therapeutics are largely unknown. Here, the synergy between ADC and epigenetic drug decitabine (DAC), a clinically approved DNA methylation inhibitor, in multiple preclinical models of melanoma specifically investigated. Mechanistically, the underlying biomechanisms of how DAC cooperatively worked with ICAM1 antibody conjugated DNA topoisomerase I inhibitor DXd (I1-DXd) is elucidated. DAC treatment significantly enhanced anti-tumor efficacy of I1-DXd by upregulating antigen expression, enhancing antibody internalization and potentiating tumor sensitivity by epigenetically reprogramming of melanoma. Meanwhile, I1-DXd/DAC combination also exerted regulatory effects on tumor microenvironment (TME) by enhancing tumor infiltration of innate and adaptive immune cells and improving penetration of ADCs with a boosted antitumor immunity. This study provides a rational ADC combination strategy for solid tumor treatment.

Microneedles-mediated calcium-ion-modulated nanoamplifier for potentiating photodynamic therapy via specific-tuning assembly and tumor microenvironment remold

Off-targeting toxicity and immunosuppressive tumor microenvironment still restrict the therapeutic requirement of photodynamic therapy (PDT). The development of metal ion-coordination-based nanoparticles (NPs) for cancer therapy has advantages, such as precious nanostructure and potent therapeutic effect as well as great safety. In this study, we prepared calcium ions (Ca2+)-coordination photosensitizer NPs, based on Ca2+-pyrochloric acid (PPA)-coordination as the new photosensitive nanoamplifiers, and microneedles (MNs) as the personalized apparatus, and investigated the nanoamplifiers for treating the melanoma via transdermal administration. This nanoamplifiers was synthesized via a simple coordination of Ca2+ and PPA with the addition of bovine serum albumin (BSA), and further fabricated into MNs (nanoamplifiers@MNs). Following inserted into the tumor, the released nanoamplifiers from the tips and back layer exhibited great photodynamic activity under irradiation, inducing cancer cell death. Meanwhile, Ca2+ acted as the second messenger, promoting M1 polarization of macrophages and maturation of dendritic cells (DCs), thereby enhancing the immune activation effect in the tumor microenvironment. As a result, such nanoamplifiers effectively achieved significant efficacy against malignant melanoma tumors by synergistically tumor killing and potent anti-tumor immune activation without obviously side effect. This work demonstrated the potential of MNs-mediated metal ion-coordination-based nanoamplifier as a novel photodynamic therapeutic platform for the efficient and safe treatment of cancer.

Thin Amelanotic and Hypomelanotic Melanoma: Clinicopathological and Dermoscopic Features

Background and Objectives: Amelanotic/hypomelanotic melanomas (AHMs) account for 2-8% of all cutaneous melanomas. Due to their clinical appearance and the lack of specific dermoscopic indicators, AHMs are challenging to diagnose, particularly in thinner cutaneous lesions. The aim of our study was to evaluate the clinicopathological and dermoscopic features of thin AHMs. Identifying the baseline clinical-pathological features and dermoscopic aspects of thin AHMs is crucial to better understand this entity. Materials and Methods: We divided the AHM cohort into two groups based on Breslow thickness: thin (≤1.00 mm) and thick (>1.00 mm). This stratification helped identify any significant clinicopathological differences between the groups. For dermoscopic analysis, we employed the "pattern analysis" approach, which involves a simultaneous and subjective assessment of different criteria. Results: Out of the 2.800 melanomas analyzed for Breslow thickness, 153 were identified as AHMs. Among these, 65 patients presented with thin AHMs and 88 with thick AHMs. Red hair color and phototype II were more prevalent in patients with thin AHMs. The trunk was the most common anatomic site for thin AHMs. Patients with thin AHMs showed a higher number of multiple melanomas. Dermoscopic analysis revealed no significant difference between thin AHMs and thick AHMs, except for a more frequent occurrence of residual reticulum in thin AHMs. Conclusions: Thin AHMs typically affect individuals with lower phototypes and red hair color. These aspects can be related to the higher presence of pheomelanin, which provides limited protection against sun damage. This also correlates with the fact that the trunk, a site commonly exposed to intermittent sun exposure, is the primary anatomical location for thin AHMs. Multiple primary melanomas are more common in patients with thin AHMs, likely due to an intrinsic predisposition as well as greater periodic dermatologic follow-ups in this class of patients. Apart from the presence of residual reticulum, no other significant dermoscopic differences were observed, complicating the differential diagnosis between thin and thick AHMs based on dermoscopy alone.

Advances in immunotherapy for mucosal melanoma: harnessing immune checkpoint inhibitors for improved treatment outcomes

Mucosal melanoma (MM) poses a significant clinical challenge due to its aggressive nature and limited treatment options. In recent years, immunotherapy has emerged as a promising strategy for MM, with a particular focus on immune checkpoint inhibitors such as PD-1 and CTLA-4 inhibitors. These inhibitors have demonstrated substantial efficacy by harnessing the body's immune response against tumors. Moreover, adoptive cell transfer (ACT), anti-angiogenic therapy, and combination therapies have garnered attention for their potential in MM treatment. ACT involves modifying T cells to target melanoma cells, showing promising antitumor activity. Anti-angiogenic therapy aims to impede tumor growth by inhibiting angiogenesis, while combination therapies, including immune checkpoint inhibitors and targeted therapies, offer a multifaceted approach to overcome treatment resistance. This comprehensive review explores the advancements in immunotherapy for MM, highlighting the role of diverse therapeutic modalities in enhancing treatment outcomes and addressing the challenges posed by this aggressive malignancy.

Enhanced Skin Penetration and Efficacy: First and Second Generation Lipoidal Nanocarriers in Skin Cancer Therapy

Skin carcinoma remains one of the most widespread forms of cancer, and its global impact continues to increase. Basal cell carcinoma, melanoma, and squamous cell carcinoma are three kinds of cutaneous carcinomas depending upon occurrence and severity. The invasive nature of skin cancer, the limited effectiveness of current therapy techniques, and constraints to efficient systems for drug delivery are difficulties linked with the treatment of skin carcinoma. In the present era, the delivery of drugs has found a new and exciting horizon in the realm of nanotechnology, which presents inventive solutions to the problems posed by traditional therapeutic procedures for skin cancer management. Lipid-based nanocarriers like solid lipid nanoparticles and nanostructured lipid carriers have attracted a substantial focus in recent years owing to their capability to improve the drug's site-specific delivery, enhancing systemic availability, and thus its effectiveness. Due to their distinct structural and functional characteristics, these nanocarriers can deliver a range of medications, such as peptides, nucleic acids, and chemotherapeutics, via different biological barriers, such as the skin. In this review, an effort was made to present the mechanism of lipid nanocarrier permeation via cancerous skin. In addition, recent research advances in lipid nanocarriers have also been discussed with the help of in vitro cell lines and preclinical studies. Being a nano size, their limitations and toxicity aspects in living systems have also been elaborated.

Feedforward cysteine regulation maintains melanoma differentiation state and limits metastatic spread

The inherent ability of melanoma cells to alter the differentiation-associated transcriptional repertoire to evade treatment and facilitate metastatic spread is well accepted and has been termed phenotypic switching. However, how these facets of cellular behavior are controlled remains largely elusive. Here, we show that cysteine availability, whether from lysosomes (CTNS-dependent) or exogenously derived (SLC7A11-dependent or as N-acetylcysteine), controls melanoma differentiation-associated pathways by acting on the melanocyte master regulator MITF. Functional data indicate that low cysteine availability reduces MITF levels and impairs lysosome functions, which affects tumor ferroptosis sensitivity but improves metastatic spread in vivo. Mechanistically, cysteine-restrictive conditions reduce acetyl-CoA levels to decrease p300-mediated H3K27 acetylation at the melanocyte-restricted MITF promoter, thus forming a cysteine feedforward regulation that controls MITF levels and downstream lysosome functions. These findings collectively suggest that cysteine homeostasis governs melanoma differentiation by maintaining MITF levels and lysosome functions, which protect against ferroptosis and limit metastatic spread.

Microparticles Made with Silk Proteins for Melanoma Adjuvant Therapy

Melanoma is one of the most aggressive forms of skin cancer, which is characterized by metastasis and poor prognosis due to the limited effectiveness of current therapies and the toxicity of conventional drugs. For this reason and in recent years, one of the most promising strategies in the treatment of this form of cancer is the use of drug delivery systems as carriers capable of conveying the therapeutic agent into the tumor microenvironment, thus preventing its degradation and improving its safety and effectiveness profiles. In the present work, microparticles based on silk fibroin and epifibroin 0039, silk-derived proteins loaded with idebenone, were created, which act as therapeutic carriers for topical use in the treatment of melanoma. The resulting particles have a spherical shape, good loading efficiency, and release capacity of idebenone. Efficacy studies have demonstrated a reduction in the proliferation of COLO-38, melanoma tumor cells, while safety tests have demonstrated that the microparticles are not cytotoxic and do not possess prosensitizing activity. Notably, transdermal release studies revealed that all particles released idebenone over more days. The analysis of the stimulatory markers of the proinflammatory process, CD54 and CD86, did not show any increase in expression, thus confirming the absence of potential prosesensitization effects of the silk fibroin-based particles. The research, therefore, found that idebenone-loaded silk protein microparticles could effectively reduce the proliferation of melanoma cells without cytotoxicity. This indicates the promise of a safe and effective treatment of melanoma.

Recombinant human adenovirus type 5 promotes anti-tumor immunity via inducing pyroptosis in tumor endothelial cells

Recombinant human type 5 adenovirus (H101) is an oncolytic virus used to treat nasopharyngeal carcinoma. Owing to the deletion of the E1B-55kD and E3 regions, H101 is believed to selectively inhibit nasopharyngeal carcinoma. Whether H101 inhibits other type of tumors via different mechanisms remains unclear. In this study we investigated the effects of H101 on melanomas. We established B16F10 melanoma xenograft mouse model, and treated the mice with H101 (1 × 108 TCID50) via intratumoral injection for five consecutive days. We found that H101 treatment significantly inhibited B16F10 melanoma growth in the mice. H101 treatment significantly increased the infiltration of CD8+ T cells and reduced the proportion of M2-type macrophages. We demonstrated that H101 exhibited low cytotoxicity against B16F10 cells, but the endothelial cells were more sensitive to H101 treatment. H101 induced endothelial cell pyroptosis in a caspase-1/GSDMD-dependent manner. Furthermore, we showed that the combination of H101 with the immune checkpoint inhibitor PD-L1 antibody (10 mg/kg, i.p., every three days for three times) exerted synergic suppression on B16F10 tumor growth in the mice. This study demonstrates that, in addition to oncolysis, H101 inhibits melanoma growth by promoting anti-tumor immunity and inducing pyroptosis of vascular endothelial cells.

Impact of Genomic Mutation on Melanoma Immune Microenvironment and IFN-1 Pathway-Driven Therapeutic Responses

The BRAFV600E mutation, found in approximately 50% of melanoma cases, plays a crucial role in the activation of the MAPK/ERK signaling pathway, which promotes tumor cell proliferation. This study aimed to evaluate its impact on the melanoma immune microenvironment and therapeutic responses, particularly focusing on immunogenic cell death (ICD), a pivotal cytotoxic process triggering anti-tumor immune responses. Through comprehensive in silico analysis of the Cancer Genome Atlas data, we explored the association between the BRAFV600E mutation, immune subtype dynamics, and tumor mutation burden (TMB). Our findings revealed that the mutation correlated with a lower TMB, indicating a reduced generation of immunogenic neoantigens. Investigation into immune subtypes reveals an exacerbation of immunosuppression mechanisms in BRAFV600E-mutated tumors. To assess the response to ICD inducers, including doxorubicin and Me-ALA-based photodynamic therapy (PDT), compared to the non-ICD inducer cisplatin, we used distinct melanoma cell lines with wild-type BRAF (SK-MEL-2) and BRAFV600E mutation (SK-MEL-28, A375). We demonstrated a differential response to PDT between the WT and BRAFV600E cell lines. Further transcriptomic analysis revealed upregulation of IFNAR1, IFNAR2, and CXCL10 genes associated with the BRAFV600E mutation, suggesting their involvement in ICD. Using a gene reporter assay, we showed that PDT robustly activated the IFN-1 pathway through cGAS-STING signaling. Collectively, our results underscore the complex interplay between the BRAFV600E mutation and immune responses, suggesting a putative correlation between tumors carrying the mutation and their responsiveness to therapies inducing the IFN-1 pathway, such as the ICD inducer PDT, possibly mediated by the elevated expression of IFNAR1/2 receptors.

The Potential of Photodynamic Therapy Using Solid Lipid Nanoparticles with Aluminum Phthalocyanine Chloride as a Nanocarrier for Modulating Immunogenic Cell Death in Murine Melanoma In Vitro

Photodynamic therapy (PDT) uses a photosensitizer to generate reactive oxygen species (ROS) that kill target cells. In cancer treatments, PDT can potentially induce immunogenic cell death (ICD), which is characterized by a well-controlled exposure of damage-associated molecular patterns (DAMPs) that activate dendritic cells (DCs) and consequently modulate the immune response in the tumor microenvironment. However, PDT still has limitations, such as the activity of photosensitizers in aqueous media and poor bioavailability. Therefore, a new photosensitizer system, SLN-AlPc, has been developed to improve the therapeutic efficacy of PDT. In vitro experiments showed that the light-excited nanocarrier increased ROS production in murine melanoma B16-F10 cells and modulated the profile of DCs. PDT induced cell death accompanied by the exposure of DAMPs and the formation of autophagosomes. In addition, the DCs exposed to PDT-treated B16-F10 cells exhibited morphological changes, increased expression of MHCII, CD86, CD80, and production of IL-12 and IFN-γ, suggesting immune activation towards an antitumor profile. These results indicate that the SLNs-AlPc protocol has the potential to improve PDT efficacy by inducing ICD and activating DCs.

Expression of immune checkpoint molecules TIGIT and TIM-3 by tumor-infiltrating lymphocytes predicts poor outcome in sinonasal mucosal melanoma

BACKGROUND

Sinonasal mucosal melanoma (SNMM) is a rare but aggressive tumor with a poor prognosis. The co-inhibitory receptors T cell immunoglobulin and mucinodomain containing-3 (TIM-3), lymphocyte activation gene-3 (LAG-3) and T cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain (TIGIT) are promising new targets in anti-cancer immunotherapy. The expression profiles of these immune checkpoint molecules (ICMs) and potential prognostic implications have not been characterized in SNMM yet.

METHODS

Immunohistochemical staining for TIGIT, LAG-3 and TIM-3 was performed on tumor tissue samples from 27 patients with primary SNMM. Associations between ICM expression and demographic parameters, AJCC tumor stage, overall survival, and recurrence-free survival were retrospectively analyzed.

RESULTS

SNMM patients with low numbers of TIGIT+ and TIM-3+ tumor infiltrating lymphocytes (TILs) in the primary tumor survived significantly longer than patients with a high degree of TIGIT+ and TIM-3+ TILs. High infiltration with TIM-3+ or TIGIT+ lymphocytes was associated with the higher T4 stage and decreased 5-year survival.

CONCLUSION

We identified high densities of TIM-3+ and TIGIT+ TILs as strong negative prognostic biomarkers in SNMM. This suggests that TIM-3 and TIGIT contribute to immunosuppression in SNMM and provides a rationale for novel treatment strategies based on this next generation of immune checkpoint inhibitors. Prospective studies with larger case numbers are warranted to confirm our findings and their implications for immunotherapy.