Oxidative Stress in Melanoma: Beneficial Antioxidant and Pro-Oxidant Therapeutic Strategies

Antioxidant effects of silver-ceria nanoparticles on the reduction of melanin in amelanotic melanoma cell biology

Although cerium oxide nanoparticles (nanoceria, CeO2) have a wide range of applications, it is imperative to consider their significant implications for human health. In particular, modifying the surface properties of CeO2 is of great importance in biomedical applications. In this study, a conventional wetness incipient impregnation technique was employed to load silver (Ag) metal onto the surface of CeO2 NPs synthesized via the hydrothermal method. Then, the antioxidant effects of silver-cerium oxide nanoparticles (Ag@CeO2 NPs) were evaluated on the melanin content of A375 skin cancer cells. The synthesized nanoparticles have been identifed using combined characterizations of the hydrodynamic size, zeta potential FTIR, FE-SEM, and UV-Vis spectra. The average particle size of Ag@CeO2 NPs was measured at 234 ± 20 nm with the zeta potential value - 33.5 mV. FE-SEM image revealed that Ag@CeO2 nanoparticles were polyhedral particles consisting of cubic nanostructures with rounded corners. The antioxidant capability of Ag@CeO2 NPs was assessed using DPPH and ABTS assays and the inhibitory effects of that on melanin biosynthesis (extracellular and cellular melanin content) were examined on human melanoma cell line. Overall, the results provide promising baseline information for the potential applications of Ag@CeO2 NPs in treating hyperpigmentation in the skin.

Emodin and Aloe-Emodin Reduce Cell Growth and Disrupt Metabolic Plasticity in Human Melanoma Cells

Background/Objectives: Melanoma is an aggressive skin cancer with intratumor metabolic heterogeneity, which drives its progression and therapy resistance. Natural anthraquinones, such as emodin and aloe-emodin, exhibit anti-cancer properties, but their effects on metabolic plasticity remain unclear. This study evaluated their impact on proliferation and metabolic pathways in heterogenous melanoma human cell lines. Methods: COLO 800, COLO 794, and A375 melanoma cell lines representing distinct metabolic phenotypes were analyzed. Targeted and untargeted metabolomics analyses integrated with Seahorse assays were performed to assess the effects of emodin and aloe-emodin on cell proliferation, mitochondrial function, and redox homeostasis. Glucose tracing using [U-13C6] glucose and metabolic flux analysis (MFA) were carried out to evaluate the glycolysis and TCA cycle dynamics. Results: Emodin and aloe-emodin inhibited proliferation by disrupting glycolysis, oxidative phosphorylation, and energy production across all cell lines. Both compounds impaired glucose metabolism, reduced TCA cycle intermediates, and induced mitochondrial ROS accumulation, causing oxidative stress and redox imbalance. Despite intrinsic metabolic differences, COLO 800 and COLO 794 upregulated antioxidant defenses; A375 enhanced one-carbon metabolism and amino acid pathways to maintain redox balance and nucleotide biosynthesis. Conclusions: Emodin and aloe-emodin can disrupt the metabolic plasticity of melanoma cells by impairing glycolysis, mitochondrial function, and redox homeostasis. Their ability to target metabolic vulnerabilities across diverse phenotypes highlights their therapeutic potential for overcoming resistance mechanisms and advancing melanoma treatment strategies.

Tangeretin regulates oxidative stress in cutaneous melanoma cells via the Nrf2 signaling pathway

Oxidative stress is a key factor in melanoma progression, making it an important therapeutic target. This study explored the effects of tangeretin, a citrus-derived flavonoid, on human melanoma A375 cells and its underlying mechanisms. A375 cells were treated with tangeretin at various concentrations. The effects of tangeretin on cell proliferation, migration, invasion, and apoptosis were assessed using MTT, wound healing, Transwell invasion, and flow cytometry assays, respectively. Oxidative stress markers, including reactive oxygen species (ROS), malondialdehyde (MDA), glutathione (GSH), and superoxide dismutase (SOD), were evaluated. Western blot was used to measure the expression levels of key proteins in the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway and apoptosis-related markers. The results showed that tangeretin significantly inhibited cell proliferation in a dose-dependent manner, induced apoptosis by increasing the Bax/Bcl-2 ratio, and suppressed cell migration and invasion. Additionally, tangeretin reduced oxidative stress by decreasing ROS and MDA levels while enhancing GSH content and SOD activity. Mechanistically, tangeretin activated the Nrf2 signaling pathway, increasing the expression of Nrf2 and its downstream antioxidant proteins heme oxygenase-1, quinone oxidoreductase 1, and γ-Glutamylcysteine synthetase. These findings suggest that tangeretin exerts anti-cancer effects on melanoma cells by regulating oxidative stress, inhibiting proliferation and metastasis, and inducing apoptosis via the Nrf2 pathway. Tangeretin may serve as a promising candidate for melanoma treatment.

Preclinical pharmaco-toxicological screening of biomimetic melanin-like nanoparticles as a potential therapeutic strategy for cutaneous melanoma

Introduction

Despite its rarity, cutaneous melanoma (CM) represents the deadliest skin cancer with a high mortality rate, an incidence on the rise, and limited therapeutic options at present. Melanin is a polymeric pigment naturally produced within melanocytes and CM cells that gained a noteworthy attention due to its pharmacological properties, and potential for the design of nanoplatforms with biomedical applications. Up to date, the utilization of melanin-like nanoparticles (MEL-NPs) in cancer treatment has been well-documented, although their efficacy in CM therapy remains scarcely investigated. The current study presents the preclinical evaluation of MEL-NPs as a potential nanomedicine for CM management.

Methods

MEL-NPs were produced through the oxidative polymerization of dopamine and characterized via electron microscopy and UV-VIS spectroscopy. The antioxidant activity was determined by using the DPPH method. The cytotoxic, anti-migratory, anti-clonogenic, pro-oxidant and pro-apoptotic properties of MEL-NPs were investigated in vitro by applying the MTT viability test, bright-field and immunofluorescence microscopy, DCFDA/H2DCFDA test, scratch assay, colony formation assay, and RT-qPCR. The irritant and anti-angiogenic effects were assessed in ovo on the vascularized chorioallantoic membrane (CAM).

Results

The as-made MEL-NPs presented a spherical morphology, an average size of 85.61 nm, a broad UV-VIS absorption spectrum, and a strong antioxidant activity. After a 24 h treatment, MEL-NPs exerted a selective cytotoxicity in SH-4 and B164A5 CM cells compared to HEMa, HaCaT, and JB6 Cl 41-5a healthy skin cells, except for the concentration of 100 µg/mL, at which their viability declined under 70%. Additionally, MEL-NPs accumulated within the intracellular space of CM cells, forming a perinuclear coating, inhibited their motility and clonogenic potential, increased intracellular oxidative stress, targeted the epithelial-to-mesenchymal transition, and induced apoptosis by altering cell morphology, nuclear aspect, F-actin and tubulin distribution, and by modulating the expression of pro- and anti-apoptotic markers. In ovo, MEL-NPs lacked irritant and vascular toxic effects, while exerting an angio-suppressive activity.

Conclusion

MEL-NPs demonstrated promising anti-melanoma properties, showing a selective cytotoxicity, a strong anti-invasive effect and a pro-apoptotic activity in CM cells, while inhibiting CAM angiogenesis, these novel findings contributing to future research on the potential application of this nanoplatform in CM therapy.

MCP-enhanced SOD3 activity inhibits gastric cancer and potentiate chemotherapy via modulating EGFR signaling

AIMS

This study aims to investigate the role of SOD3 in gastric cancer (GC) progression and its impact on chemotherapy efficacy and toxicity. It further seeks to evaluate the therapeutic potential of MCP in enhancing SOD3 activity to improve treatment outcomes and reduce chemotherapy-induced peripheral neurotoxicity (CIPN).

MATERIALS AND METHODS

We used overexpression plasmids and small interfering RNAs (siRNAs) to modulate the expression of SOD3 and Desmocollin2 (DSC2) in gastric cancer cells. Molecular biology experiments were performed to analyze pathway-related protein expression and molecular interactions. In vitro and in vivo experiments were conducted to evaluate the effects of modified citrus pectin (MCP) and oxaliplatin (OXA), individually and in combination, on gastric cancer progression and CIPN.

KEY FINDINGS

SOD3 inhibited the proliferation, migration, and invasion of GC cells via SOD3/EGFR/PKP3/DSC2 axis. MCP selectively increased SOD3 levels and enhanced its anti-tumor effects. Combined treatment with MCP and OXA synergistically inhibited GC progression in vitro and in vivo, while MCP alleviated CIPN, enabling OXA dose reduction without compromising efficacy.

SIGNIFICANCE

The findings revealed that SOD3 played a critical tumor-suppressive role in gastric cancer by modulating the SOD3/EGFR/PKP3/DSC2 axis. MCP, a natural compound that selectively boosted SOD3 levels, enhanced chemotherapy efficacy while reducing peripheral neurotoxicity, providing a promising strategy to improve gastric cancer treatment and mitigate chemotherapy-related side effects.

From Bench to Bedside: ROS-Responsive Nanocarriers in Cancer Therapy

Reactive oxygen species (ROS) play a dual role in cancer, acting as both signaling molecules that promote tumour growth and as agents that can inhibit tumour progression through cytotoxic effects. In cancer therapy, ROS-responsive drug delivery systems take advantage of the elevated ROS levels found in tumors compared to healthy tissues. These systems are engineered to release drugs precisely in response to increased ROS levels in tumour cells, allowing targeted and controlled treatment, minimizing side effects, and enhancing therapeutic outcomes. ROS generation in cancer cells is linked to metabolic changes, mitochondrial dysfunction, and oncogenic signaling, leading to increased oxidative stress. Tumour cells manage this by upregulating antioxidant defenses to prevent ROS from reaching harmful levels. This balance between ROS production and neutralization is critical for cancer cell survival, making ROS both a challenge and an opportunity for targeted therapies. ROS also connect inflammation and cancer. Chronic inflammation leads to elevated ROS, which can damage DNA and proteins, promoting mutations and cancer development. Additionally, ROS contribute to protein degradation, affecting essential cellular functions. Therapeutic strategies targeting ROS aim to either increase ROS beyond tolerable levels for cancer cells or inhibit their antioxidant defenses. Nanocarriers responsive to ROS show great potential in improving the precision of cancer treatments by releasing drugs specifically in high ROS environments, like tumors. This review discusses the mechanisms of ROS in cancer, its role in inflammation and protein degradation, and the advances in ROS-targeted nanocarrier therapies across different cancer types.

Evaluation of the Anti-Cancer Potential of Extracellular Vesicles Derived from Human Amniotic Fluid Stem Cells: Focus on Effective miRNAs in the Treatment of Melanoma Progression

Mesenchymal stromal cells (MSCs) and their secretome show intrinsic antitumor properties, however, the anti-cancer effects of MSCs remain debated and depend on the cancer type or model. MSCs derived from discarded samples, such as human amniotic fluid (hAFSC), have been introduced as an attractive and potent stem cell source for clinical applications due to their collection procedures, which minimize ethical issues. Until now, various studies have obtained controversial results and poor understanding of the mechanisms behind the effects of perinatal cells on cancer cells. To better clarify this aspect, protein and miRNA expression profiling isolated from Extracellular vesicles (EVs) secreted by hAFSCs, obtained in the II or III trimester, were evaluated. Bioinformatic analysis was performed aiming at evaluating differential expression, pathway enrichment, and miRNA-mRNA networks. We highlighted that most of the highest expressed proteins and miRNAs are mainly involved in antioxidant and anti-cancer effects. Indeed, in the presence of hAFSC-EVs, a reduction of the G2/M phase was observed on melanoma cell lines, an activation of the apoptotic pathway occurred and the migration and invasion ability reduced. Our data demonstrated that II or III trimester hAFSCs can release bioactive factors into EVs, causing an efficient anti-cancer effect inhibiting melanoma progression.

Emerging Mechanisms of Physical Exercise Benefits in Adjuvant and Neoadjuvant Cancer Immunotherapy

The primary factors that can be modified in one's lifestyle are the most influential determinants and significant preventable causes of various types of cancer. Exercise has demonstrated numerous advantages in preventing cancer and aiding in its treatment. However, the precise mechanisms behind these effects are still not fully understood. To contribute to our comprehension of exercise's impact on cancer immunotherapy and provide recommendations for future research in exercise oncology, we will examine the roles and underlying mechanisms of exercise on immune cells. In addition to reducing the likelihood of developing cancer, exercise can also improve the effectiveness of certain approved anticancer treatments, such as targeted therapy, immunotherapy, and radiotherapy. Exercise is a pivotal modulator of the immune response, and thus, it can play an emerging important role in new immunotherapies. The mechanisms responsible for these effects involve the regulation of intra-tumoral angiogenesis, myokines, adipokines, their associated pathways, cancer metabolism, and anticancer immunity. Our review assesses the potential of physical exercise as an adjuvant/neoadjuvant tool, reducing the burden of cancer relapse, and analyzes emerging molecular mechanisms predicting favorable adjuvanticity effects.

Melanoma Metabolism: Molecular Mechanisms and Therapeutic Implications in Cutaneous Oncology

BACKGROUND

Melanoma, a highly aggressive skin cancer, is characterized by rapid progression and a high metastatic potential, presenting significant challenges in clinical oncology. A critical aspect of melanoma biology is its metabolic reprogramming, which supports tumor growth, survival, and therapeutic resistance.

OBJECTIVE

This review aims to explore the key molecular mechanisms driving metabolic alterations in melanoma and their implications for developing therapeutic strategies.

METHODS

A Pubmed search was conducted to analyze literature discussing key mechanisms of the Warburg effect, mitochondrial dysfunction, enhanced lipid metabolism, epigenetic modifications, and the tumor microenvironment.

RESULTS

Metabolic reprogramming supports melanoma growth, proliferation, and survival. Understanding these complex metabolic dynamics provides valuable insights for developing targeted therapeutic strategies.

CONCLUSION

Potential therapeutic interventions aimed at disrupting melanoma metabolism highlight the promise of precision medicine in improving treatment outcomes in cutaneous oncology. By targeting metabolic vulnerabilities, novel treatment approaches could significantly enhance the clinical management and prognosis of melanoma.

Ursolic acid interaction with transcription factors BRAF, V600E, and V600K: a computational approach towards new potential melanoma treatments

CONTEXT

Melanoma is one of the cancers with the highest mortality rate for its ability to metastasize. Several targets have undergone investigation for the development of drugs against this pathology. One of the main targets is the kinase BRAF (RAF, rapidly accelerated fibrosarcoma). The most common mutation in melanoma is BRAFV600E and has been reported in 50-90% of patients with melanoma. Due to the relevance of the BRAFV600E mutation, inhibitors to this kinase have been developed, vemurafenib-OMe and dabrafenib. Ursolic acid (UA) is a pentacyclic triterpene with a privileged structure, the pentacycle scaffold, which allows to have a broad variety of biological activity; the most studied is its anticancer capacity. In this work, we reported the interaction profile of vemurafenib-OMe, dabrafenib, and UA, to define whether UA has binding capacity to BRAFWT, BRAFV600E, and BRAFV600K. Homology modeling of BRAFWT, V600E, and V600K; molecular docking; and molecular dynamics simulations were carried out and interactions and residues relevant to the binding of the inhibitors were obtained. We found that UA, like the inhibitors, presents hydrogen bond interactions, and hydrophobic interactions of van der Waals, and π-stacking with I463, Q530, C532, and F583. The ΔG of ursolic acid in complex with BRAFV600K (- 63.31 kcal/mol) is comparable to the ΔG of the selective inhibitor dabrafenib (- 63.32 kcal/mol) in complex to BRAFV600K and presents a ΔG like vemurafenib-OMe with BRAFWT and V600E. With this information, ursolic acid could be considered as a lead compound for design cycles and to optimize the binding profile and the selectivity towards mutations for the development of new selective inhibitors for BRAFV600E and V600K to new potential melanoma treatments.

METHODS

The homology modeling calculations were executed on the public servers I-TASSER and ROBETTA, followed by molecular docking calculations using AutoGrid 4.2.6, AutoDockGPU 1.5.3, and AutoDockTools 1.5.6. Molecular dynamics and metadynamics simulations were performed in the Desmond module of the academic version of the Schrödinger-Maestro 2020-4 program, utilizing the OPLS-2005 force field. Ligand-protein interactions were evaluated using Schrödinger-Maestro program, LigPlot + , and PLIP (protein-ligand interaction profiler). Finally, all of the protein figures presented in this article were made in the PyMOL program.

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.

Cellular Basis of Adjuvant Role of n-3 Polyunsaturated Fatty Acids in Cancer Therapy: Molecular Insights and Therapeutic Potential against Human Melanoma

Human melanoma is a highly aggressive malignant tumor originating from epidermal melanocytes, characterized by intrinsic resistance to apoptosis and the reprogramming of proliferation and survival pathways during progression, leading to high morbidity and mortality rates. This malignancy displays a marked propensity for metastasis and often exhibits poor responsiveness to conventional therapies. Fatty acids, such as n-3 polyunsaturated fatty acids (PUFAs) docosahexaenoic and eicosapentaenoic acids, exert various physiological effects on melanoma, with increasing evidence highlighting the anti-tumorigenic, anti-inflammatory, and immunomodulatory properties. Additionally, n-3 PUFAs have demonstrated their ability to inhibit cancer metastatic dissemination. In the context of cancer treatment, n-3 PUFAs have been investigated in conjunction with chemotherapy as a potential strategy to mitigate severe chemotherapy-induced side effects, enhance treatment efficacy and improve safety profiles, while also enhancing the responsiveness of cancer cells to chemotherapy. Furthermore, dietary intake of n-3 PUFAs has been associated with numerous health benefits, including a decreased risk and improved prognosis in conditions such as heart disease, autoimmune disorders, depression and mood disorders, among others. However, the specific mechanisms underlying their anti-melanoma effects and outcomes remain controversial, particularly when comparing findings from in vivo or in vitro experimental studies to those from human trials. Thus, the objective of this review is to present data supporting the potential role of n-3 PUFA supplementation as a novel complementary approach in the treatment of malignant cancers such as melanoma.

Salidroside induces mitochondrial dysfunction and ferroptosis to inhibit melanoma progression through reactive oxygen species production

Reactive oxygen species (ROS) induces necroptotic and ferroptosis in melanoma cells. Salidroside (SAL) regulates ROS in normal cells and inhibits melanoma cell proliferation. This study used human malignant melanoma cells treated with SAL either alone or in combination with ROS scavenger (NAC) or ferroptosis inducer (Erastin). Through cell viability, wound healing assays, and a Seahorse analyze found that SAL inhibited cell proliferation, migration, extracellular acidification rate, and oxygen consumption rate. Metabolic flux analysis, complexes I, II, III, and IV activity of the mitochondrial respiratory chain assays, mitochondrial membrane potential assay, mitochondrial ROS, and transmission electron microscope revealed that SAL induced mitochondrial dysfunction and ultrastructural damage. Assessment of malondialdehyde, lipid ROS, iron content measurement, and Western blot analysis showed that SAL activated lipid peroxidation and promoted ferroptosis in A-375 cells. These effects were abolished after NAC treatment. Additionally, SAL and Erastin both inhibited cell proliferation and promoted cell death; SAL increased the Erastin sensitivity of cells while NAC antagonized it. In xenograft mice, SAL inhibited melanoma growth and promoted ROS-dependent ferroptosis. SAL induced mitochondrial dysfunction and ferroptosis to block melanoma progression through ROS production, which offers a scientific foundation for conducting SAL pharmacological research in the management of melanoma.