The role of oxidative stress in the biology of melanoma: A systematic review

Cyclodextrin encapsulation enabling the anticancer repositioning of disulfiram: Preparation, analytical and in vitro biological characterization of the inclusion complexes

Drug repositioning is a high-priority and feasible strategy in the field of oncology research, where the unmet medical needs are continuously unbalanced. Disulfiram is a potential non-chemotherapeutic, adjuvant anticancer agent. However, the clinical translation is limited by the drug's poor bioavailability. Therefore, the molecular encapsulation of disulfiram with cyclodextrins is evaluated to enhance the solubility and stability of the drug. The present work describes for the first time the complexation of disulfiram with randomly methylated-β-cyclodextrin. A parallel analytical andin vitrobiological comparison of disulfiram inclusion complexes with hydroxypropyl-β-cyclodextrin, randomly methylated-β-cyclodextrin and sulfobutylether-β-cyclodextrin is conducted. A significant drug solubility enhancement by about 1000-folds and fast dissolution in 1 min is demonstrated. Thein vitrodissolution-permeation studies and proliferation assays demonstrate the solubility-dependent efficacy of the drug. Throughout the different cancer cell lines' characteristics and disulfiram unspecific antitumoral activity, the inhibitory efficacy of the cyclodextrin encapsulated drug on melanoma (IC50 about 100 nM) and on glioblastoma (IC50 about 7000 nM) cell lines differ by a magnitude. This pre-formulation screening experiment serves as a proof of concept of using cyclodextrin encapsulation as a platform tool for further drug delivery development in repositioning areas.

Benzimidazole-oxindole hybrids as multi-kinase inhibitors targeting melanoma

In the current study, a series of benzimidazole-oxindole conjugates 8a-t were designed and synthesized as type II multi-kinase inhibitors. They exhibited moderate to potent inhibitory activity against BRAFWT up to 99.61 % at 10 µM. Notably, compounds 8e, 8k, 8n and 8s demonstrated the most promising activity, with 99.44 to 99.61 % inhibition. Further evaluation revealed that 8e, 8k, 8n and 8s exhibit moderate to potent inhibitory effects on the kinases BRAFV600E, VEGFR-2, and FGFR-1. Additionally, compounds 8a-t were screened for their cytotoxicity by the NCI, and several compounds showed significant growth inhibition in diverse cancer cell lines. Compound 8e stood out with a GI50 range of 1.23 - 3.38 µM on melanoma cell lines. Encouraged by its efficacy, it was further investigated for its antitumor activity and mechanism of action, using sorafenib as a reference standard. The hybrid compound 8e exhibited potent cellular-level suppression of BRAFWT, VEGFR-2, and FGFR-1 in A375 cell line, surpassing the effects of sorafenib. In vivo studies demonstrate that 8e significantly inhibits the growth of B16F10 tumors in mice, leading to increased survival rates and histopathological tumor regression. Furthermore, 8e reduces angiogenesis markers, mRNA expression levels of VEGFR-2 and FGFR-1, and production of growth factors. It also downregulated Notch1 protein expression and decreased TGF-β1 production. Molecular docking simulations suggest that 8e binds as a promising type II kinase inhibitor in the target kinases interacting with the key regions in their kinase domain.

A H2O2-specific fluorescent probe for evaluating oxidative stress in pesticides-treated cells, rice roots and zebrafish

Hydrogen peroxide (H2O2) plays an irreplaceable role in the evaluation of the redox status in versatile circumstances. The levels of H2O2 can be affected by both internal and external stimuli, including environmental hazards. Abnormal production of H2O2 is a common characteristic of pesticide-caused damage. Therefore, H2O2 levels can intuitively and conveniently reflect the oxidative stress caused by various pesticides in cells and organisms. However, reliable and convenient monitoring of H2O2 in living cells is still limited by the lack of specific imaging probes. In this study, a fluorescent probe (HBTM-HP) was developed for in situ observation of H2O2 fluctuations caused by pesticide treatment over time in mammalian cells, rice roots and zebrafish. HBTM-HP showed high sensitivity and selectivity for H2O2. Fluorescence imaging results confirmed that HBTM-HP could be applied to reveal H2O2 production induced by multiple pesticides. This study revealed that HBTM-HP could serves as a versatile tool to monitor the redox status related to H2O2 both in vitro and in vivo upon exposure to pesticides, and also provides a basis for clarifying the mechanisms of pesticides in physiological and pathological processes.

Oxidative stress affects the beginning of the growth of cancer cells through a variety of routes

Oxidative stress is a physiological condition that occurs when there is an imbalance between the production of reactive oxygen species (ROS) and the cell's antioxidant defense system. ROS are highly reactive molecules that can cause damage to cellular structures such as DNA, proteins, and lipids. the regulation of ROS levels and the antioxidant defense system is crucial for cancer prevention and treatment. Strategies to enhance antioxidant defenses or induce oxidative stress selectively in cancer cells are being developed as potential therapeutic approaches. targeting oxidative stress in cancer treatment is an active area of research with several potential therapeutic approaches being investigated. Developing selective and effective therapies that target oxidative stress in cancer cells while sparing normal cells will be crucial for improving cancer treatment outcomes.

The Role of Nutraceuticals and Functional Foods in Skin Cancer: Mechanisms and Therapeutic Potential

Skin cancer is a prevalent type of cancer worldwide and has a high growth rate compared to other diseases. Although modern targeted therapies have improved the management of cutaneous neoplasms, there is an urgent requirement for a safer, more affordable, and effective chemoprevention and treatment strategy for skin cancer. Nutraceuticals, which are natural substances derived from food, have emerged as a potential alternative or adjunctive treatment option. In this review, we explore the current evidence on the use of omega-3 fatty acids and polyphenols (curcumin, epigallocatechin gallate, apigenin, resveratrol, and genistein) for the treatment of melanoma and non-melanoma skin cancer (NMSC), as well as in their prevention. We discuss the mechanisms of action of the aforementioned nutraceuticals and their probable therapeutic benefits in skin cancer. Omega-3 fatty acids, curcumin, epigallocatechin gallate, apigenin, resveratrol, and genistein have several properties, among which are anti-inflammatory and anti-tumor, which can help to prevent and treat skin cancer. However, their effectiveness is limited due to poor bioavailability. Nanoparticles and other delivery systems can improve their absorption and targeting. More research is needed to evaluate their safety and effectiveness as a natural approach to skin cancer prevention and treatment. These compounds should not replace conventional cancer treatments, but may be used as complementary therapy under the guidance of a healthcare professional.

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

Cutaneous melanoma ranks as the fifth most common cancer in the United States and represents one of the deadliest forms of skin cancer. While recent advances in systemic targeted therapies and immunotherapies have positively impacted melanoma survival, the survival rate of stage IV melanoma remains at a meager 32%. Unfortunately, tumor resistance can impede the effectiveness of these treatments. Oxidative stress is a pivotal player in all stages of melanoma progression, with a somewhat paradoxical function that promotes tumor initiation but hinders vertical growth and metastasis in later disease. As melanoma progresses, it employs adaptive mechanisms to lessen oxidative stress in the tumor environment. Redox metabolic rewiring has been implicated in acquired resistance to BRAF/MEK inhibitors. A promising approach to enhance the response to therapy involves boosting intracellular ROS production using active biomolecules or targeting enzymes that regulate oxidative stress. The complex interplay between oxidative stress, redox homeostasis, and melanomagenesis can also be leveraged in a preventive context. The purpose of this review is to provide an overview of oxidative stress in melanoma, and how the antioxidant system may be manipulated in a therapeutic context for improved efficacy and survival.

Genes associated with cellular senescence favor melanoma prognosis by stimulating immune responses in tumor microenvironment

PURPOSE

Skin cutaneous melanoma (SKCM), a malignant tumor from melanocytes, is the fifth most prevalent tumor. Immune checkpoint inhibitor (ICI) immunotherapy improves prognosis of SKCM, but immune response varies for different populations. Cellular senescence in the tumor microenvironment (TME) promotes antitumor immunity, mediated by dendritic cells (DC) and CD8+ T cells. Therefore, we sought to explore the role of cellular senescence in the TME of SKCM through bioinformatics and machine learning.

METHODS

First, we obtained 93 cellular senescence-prognosis genes (CSPGs) by univariate survival analysis. Thereafter, 23 optimal CSPGs were obtained by least absolute shrinkage and selection operator (lasso) analysis. Based on the riskscore obtained by lasso analysis and clinical information from multivariate cox, we obtained the nomogram of SKCM, which was validated in the validation cohort. Based on the riskscore, the patients were split into low- and high-risk groups. Functional differences between the two groups were analyzed using Metascape and GSEA, and immune infiltration differences were achieved by multiple algorithms. We obtained a risk prediction nomogram for the validated SKCM based on the lasso model by univariate and multivariate cox regression analysis.

RESULTS

In the low-risk group, immune responses were in an active state. NK, CD8+ T, DC, macrophages, and neutrophils were significantly upregulated, and ICI-relevant genes were notably upregulated. With the differentially expressed genes (DEGs) and optimal CSPGs, we obtained the hub genes: NOX4, NTN4, PROX1, and TRPM8. The hub genes were mainly expressed by cancer-associated fibroblasts (CAFs) and endothelial cells by single cell analysis, which were mainly associated with angiogenesis.

CONCLUSION

Genes associated with cellular senescence favor SKCM prognosis by stimulating immune responses in TME. Patients with high expression of cellular senescence associated genes in the TME might have better benefit from ICI immunotherapy. Cellular senescence functions as a pro-tumor agent in mesenchymal cells and needs further study.

Immunosenescence and Skin: A State of Art of Its Etiopathogenetic Role and Crucial Watershed for Systemic Implications

Immunosenescence is a complex multifactorial phenomenon consisting of wide-ranging remodeling of the immune system during the life span, resulting in an age-related qualitative-quantitative decline of immune cells and cytokines. A growing body of evidence in the international literature is highlighting the etiopathogenetic role of skin immunosenescence in the onset of various dermatologic conditions. Skin immunosenescence also serves as an interesting watershed for the onset of system-wide conditions in the context of allergic inflammation. Moreover, in recent years, an increasingly emerging and fascinating etiopathogenetic parallelism has been observed between some mechanisms of immunosenescence, both at cutaneous and systemic sites. This would help to explain the occurrence of apparently unconnected comorbidities. Throughout our review, we aim to shed light on emerging immunosenescent mechanisms shared between dermatologic disorders and other organ-specific diseases in the context of a more extensive discussion on the etiopathogenetic role of skin immunosenescence. A promising future perspective would be to focus on better understanding the mutual influence between skin and host immunity, as well as the influence of high inter-individual variability on immunosenescence/inflammaging. This can lead to a more comprehensive "immunobiographic" definition of each individual.

Dual Role of DUOX1-Derived Reactive Oxygen Species in Melanoma

Melanoma is the most serious type of skin cancer. Inflammation and oxidative stress play an essential role in the development of several types of cancer, including melanoma. Although oxidative stress promotes tumor growth, once cells escape from the primary tumor, they are subjected to a more hostile environment, with higher levels of oxidative stress typically killing most cancer cells. As Dual Oxidase 1 (DUOX1) is a major producer of reactive oxygen species (ROS) in epithelia, we used allotransplantation and autochthonous melanoma models in zebrafish together with in silico analysis of the occurrence and relevance of DUOX1 expression of the skin cutaneous melanoma (SKCM) cohort of The Cancer Genome Atlas (TCGA) to address the role of this enzyme in the aggressiveness of melanoma cells in vivo. It was found that high transcript levels of the gene encoding DUOX1 were associated with the poor prognosis of patients in the early-stage melanoma of TCGA cohort. However, DUOX1 transcript levels were not found to be associated to the prognosis of late-stage SKCM patients. In addition, the transcript level of DUOX1 in metastatic SKCM was lower than in primary SKCM. Using zebrafish primary melanoma and allotransplantation models, we interrogated the role of DUOX1 in vivo. Our results confirmed a dual role of DUOX1, which restrains melanoma proliferation but promotes metastasis. As this effect is only observed in immunocompromised individuals, the immune system appears to be able to counteract this elevated metastatic potential of DUOX1-deficient melanomas.

Intense Pulsed Light Attenuates Oxidative Stress in Perennial Allergic Conjunctivitis

Objective: To assess the effects of intense pulsed light (IPL) on oxidative stress (OS) in perennial allergic conjunctivitis (PAC). Background: IPL treatment has been proven effective for dry eye disease (DED). However, we have observed that, after IPL treatment, some patients with DED combined with allergic conjunctivitis (AC), an immune response condition in which excessive OS causes and exacerbates inflammatory damage, not only show an improvement in eye dryness, but also their AC-related eye itching is relieved. The mechanism by which IPL inhibits allergic reactions is not clear. Methods: Five patients with moderate-to-severe PAC were given two IPL treatments on the periorbital skin with a 2-week interval. Visual analog scale (VAS) scores and signs of AC, including eye redness and conjunctival follicles, were assessed before the first treatment (day 1) and 2 weeks after the second treatment (day 30). Tears were also collected at the same time, and lipid oxidation (LPO) metabolite analysis was performed using liquid chromatography tandem mass spectrometry (LC-MS/MS) to investigate the effects of IPL on OS response. Results: The average VAS score significantly decreased with treatment (30.2 for day 1, 10.6 for day 30; p < 0.001). The general signs of PAC showed no difference (p > 0.05). LPO metabolite analysis revealed that 17,18-diHETE, which is an oxidation product of eicosapentaenoic acid, and 13-OXoODE, which is an oxidation product of linoleic acid, are significantly downregulated after IPL treatment. Conclusions: The photothermal effect of IPL attenuates OS in PAC, and this seems to be one of the mechanisms by which IPL treatment improves PAC. Clinical Trial Registration number: ChiCTR1900022202.

Inhibition of Tumor Growth and Modulation of Antioxidant Activity of Rhodoxanthin Isolated from Taxus baccata Aril against B16F10 Murine Malignant Melanoma

Malignant melanoma is the most aggressive type of skin cancer, and due to the numerous limitations of current treatment methods, there is an urgent need to develop novel approaches for both the prevention and treatment of malignant melanoma, with research-oriented bioactive substances representing a notable first step. The current study decided to expand on previous rhodoxanthin research by investigating the possible anti-tumor effect as well as the effect on the antioxidant status in the case of murine melanoma in an experimental model. The 21-day study was carried out on female C57BL/6J mice. On the first day of the experiment, they were subcutaneously inoculated with 106 B16F10 cells and were given rhodoxanthin orally until the end of the study. Rhodoxanthin supplementation significantly reduced tumor growth (42.18%) and weight (15.74%). Furthermore, the epidermal growth factor (EGF) activity was reduced and the concentration of 8-OHdG dropped in the treated melanoma-bearing mice compared to the untreated ones, demonstrating the role of rhodoxanthin in slowing tumor growth, one of the mechanisms being the reduction of EGF level and the decrease of DNA oxidation. The administration of rhodoxanthin determined variations in antioxidant enzymes, both at the plasma level and at the tissue level.

Role of HMGB1 in Cutaneous Melanoma: State of the Art

High-mobility Group Box 1 (HMGB1) is a nuclear protein that plays a key role in acute and chronic inflammation. It has already been studied in several diseases, among them melanoma. Indeed, HMGB1 is closely associated with cell survival and proliferation and may be directly involved in tumor cell metastasis development thanks to its ability to promote cell migration. This research aims to assess the role of this molecule in the pathogenesis of human melanoma and its potential therapeutic role. The research has been conducted on the PubMed database, and the resulting articles are sorted by year of publication, showing an increasing interest in the last five years. The results showed that HMGB1 plays a crucial role in the pathogenesis of skin cancer, prognosis, and therapeutical response to therapy. Traditional therapies target this molecule indirectly, but future perspectives could include the development of new target therapy against HMGB1, thus adding a new approach to the therapy, which has often shown primary and secondary resistance. This could add a new therapy arm which has to be prolonged and specific for each patient.

Novel potential NOX2 inhibitors, Dudleya brittonii water extract and polygalatenoside A inhibit intracellular ROS generation and growth of melanoma

Reactive oxygen species (ROS) are key regulators of the proliferation, metastasis, and drug resistance of melanoma, which accounts for 60% of skin cancer deaths. In a previous study, we developed Dudleya brittonii water extract (DBWE) with antioxidant activity, but the mechanism of action and bioactive substances of DBWE have not been fully identified. This study showed altered NADPH oxidase 2 (NOX2) expression and selective inhibition of cytosolic ROS but not mitochondrial ROS in B16-F10 melanoma cells, suggesting the NOX2 inhibitory potential of DBWE. In addition, DBWE inhibited mitochondrial activity, lipid metabolism, and cell cycle in B16-F10 cells. The anti-melanoma effect of DBWE was abrogated by the addition of ROS, and there was no significant change in the melanogenesis pathway. Polygalatenoside A was identified as a candidate bioactive substance in the DBWE aqueous fraction through mass spectrometry, and the DBWE-like anti-melanoma effect was confirmed. These data suggest that DBWE and polygalatenoside A have the potential to prevent and treat melanoma.

Effect of Hybrid Organotin Compound on Activity of LPO and Antioxidant Protection of the Liver Tissues in Animals with Melanoma B16

The central element of the "metastatic organotropism" is a shift of the pro/antioxidant balance in cells and activation of oxidative stress and protective antioxidant systems. We studied the effects of bis(3,5-di-tert-butyl-4-hydroxyphenylthiolate)dimethylol (Me-3) in the maximum effective and toxic total doses on the level of markers of oxidative stress and antioxidant protection in the liver of mice with melanoma B16 before the appearance of macroscopic metastases. In 48 h after tumor inoculation, Me-3 was administered intraperitoneally once a day for 5 days in total doses of 375 and 500 mg/kg according to the classical method. Administration of the hybrid organotin compound Me-3 produced different effects on the pro/antioxidant state of the microenvironment of liver tissue as the target of melanoma B16 metastasis. The results suggest that inversion of the anti/prooxidant profile of Me-3 is determined by its dose.

Overcoming chemoresistance to b-raf inhibitor in melanoma via targeted inhibition of phosphoenolpyruvate carboxykinase1 using 3-mercaptopropionic acid

The resistance of melanoma to BRAF inhibitors remains a tough clinical challenge. In order to explore the underlying mechanism of drug resistance in melanoma, we established the resistant cell line to vemurafenib, and assessed the changes of drug-resistant cells on proliferation, apoptosis, oxidative stress and tumor stemness. Our results suggest that phosphoenolpyruvate carboxykinase1 (PCK1) is activated and inhibits the oxidative stress caused by vemurafenib in drug-resistant cells. Long term treatment of vemurafenib increases the expression of PCK1 which reduces the production of reactive oxygen species (ROS) by activating PI3K/Akt pathway. After the inhibition of PCK1 by 3-mercaptopropionic acid (3-MPA), the therapeutic sensitivity of vemurafenib is restored. In conclusion, this study disclosed that drug-resistant cells appeared to regulate their own proliferation, oxidative stress and tumor dryness by activating Akt/PCK1/ROS pathway, and shed new insights into acquiring drug resistance in melanoma.

Proteomic Response Revealed Signaling Pathways Involving in the Mechanism of Polymyxin B-Induced Melanogenesis

Polymyxin B is a last-line antibiotic for extensively resistant Gram-negative bacterial infection. Skin hyperpigmentation is a serious side effect induced by polymyxin B that severely compromises the psychological health and compliance of patients. The literature lacks mechanistic studies that explain how hyperpigmentation occurs, and this substantially hinders the development of intervention strategies and improved compliance. SK-MEL-2 cells were used for the polymyxin B-induced hyperpigmentation mechanism study. Melanin content and tyrosinase activity were measured after polymyxin B treatment. Tandem mass tag (TMT)-labeling quantitative proteomics was employed to investigate the response of SK-MEL-2 cells to polymyxin B treatment. Real-time quantitative PCR and Western blot were applied to validate the mRNA and protein levels of related genes and proteins. The melanin content and tyrosinase activity were significantly upregulated after polymyxin B treatment in SK-MEL-2 cells at 48 h and 72 h. Quantitative proteomics showed that 237 proteins were upregulated and 153 proteins were downregulated in the 48 h group, and 49 proteins were upregulated and 49 proteins were downregulated in the 72 h group. The differentially expressed proteins were involved in pathways such as lysosome, PI3K/Akt signaling pathway, and calcium signaling pathway. The upregulation of melanogenic enzymes and microphthalmia-associated transcription factor (MITF) was validated by qPCR and Western blot. Meanwhile, phosphorylation of PI3K, β-catenin, and cyclic-AMP response binding protein (CREB) in response to polymyxin B treatment was observed. The present study reveals the proteomic response of polymyxin B-induced melanogenesis in SK-MEL-2 cells for the first time. Signaling pathways, including melanin biosynthesis, PI3K/Akt, and calcium signaling pathways may be involved in the mechanism of melanogenesis. IMPORTANCE Polymyxin B-induced skin hyperpigmentation seriously affects the psychological health and compliance of patients. This study provides a proteomic clue to the mechanism at the cellular level for understanding polymyxin B-induced hyperpigmentation, contributing to a follow-up investigation of the corresponding PI3K/Akt signaling transduction pathway and calcium signaling pathway. The elucidation of its underlying mechanism is of great significance for patients' compliance improvement, intervention strategy, and new drug development.

NRF2 and Key Transcriptional Targets in Melanoma Redox Manipulation

Melanocytes are dendritic, pigment-producing cells located in the skin and are responsible for its protection against the deleterious effects of solar ultraviolet radiation (UVR), which include DNA damage and elevated reactive oxygen species (ROS). They do so by synthesizing photoprotective melanin pigments and distributing them to adjacent skin cells (e.g., keratinocytes). However, melanocytes encounter a large burden of oxidative stress during this process, due to both exogenous and endogenous sources. Therefore, melanocytes employ numerous antioxidant defenses to protect themselves; these are largely regulated by the master stress response transcription factor, nuclear factor erythroid 2-related factor 2 (NRF2). Key effector transcriptional targets of NRF2 include the components of the glutathione and thioredoxin antioxidant systems. Despite these defenses, melanocyte DNA often is subject to mutations that result in the dysregulation of the proliferative mitogen-activated protein kinase (MAPK) pathway and the cell cycle. Following tumor initiation, endogenous antioxidant systems are co-opted, a consequence of elevated oxidative stress caused by metabolic reprogramming, to establish an altered redox homeostasis. This altered redox homeostasis contributes to tumor progression and metastasis, while also complicating the application of exogenous antioxidant treatments. Further understanding of melanocyte redox homeostasis, in the presence or absence of disease, would contribute to the development of novel therapies to aid in the prevention and treatment of melanomas and other skin diseases.

Continuous ZnO nanoparticle exposure induces melanoma-like skin lesions in epidermal barrier dysfunction model mice through anti-apoptotic effects mediated by the oxidative stress–activated NF-κB pathway

Background

Increasing interest in the hazardous properties of zinc oxide nanoparticles (ZnO NPs), commonly used as ultraviolet filters in sunscreen, has driven efforts to study the percutaneous application of ZnO NPs to diseased skin; however, in-depth studies of toxic effects on melanocytes under conditions of epidermal barrier dysfunction remain lacking.

Methods

Epidermal barrier dysfunction model mice were continuously exposed to a ZnO NP-containing suspension for 14 and 49 consecutive days in vivo. Melanoma-like change and molecular mechanisms were also verified in human epidermal melanocytes treated with 5.0 µg/ml ZnO NPs for 72 h in vitro.

Results

ZnO NP application for 14 and 49 consecutive days induced melanoma-like skin lesions, supported by pigmented appearance, markedly increased number of melanocytes in the epidermis and dermis, increased cells with irregular nuclei in the epidermis, recruited dendritic cells in the dermis and dysregulated expression of melanoma-associated gene Fkbp51, Trim63 and Tsp 1. ZnO NPs increased oxidative injury, inhibited apoptosis, and increased nuclear factor kappa B (NF-κB) p65 and Bcl-2 expression in melanocytes of skin with epidermal barrier dysfunction after continuously treated for 14 and 49 days. Exposure to 5.0 µg/ml ZnO NPs for 72 h increased cell viability, decreased apoptosis, and increased Fkbp51 expression in melanocytes, consistent with histological observations in vivo. The oxidative stress–mediated mechanism underlying the induction of anti-apoptotic effects was verified using the reactive oxygen species scavenger N-acetylcysteine.

Conclusions

The entry of ZnO NPs into the stratum basale of skin with epidermal barrier dysfunction resulted in melanoma-like skin lesions and an anti-apoptotic effect induced by oxidative stress, activating the NF-κB pathway in melanocytes.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01308-w.

Novel possibility for cutaneous melanoma treatment by means of rosmarinic acid action on purinergic signaling

Cancer cases have increased significantly in Brazil and worldwide, with cutaneous melanoma (CM) being responsible for nearly 57,000 deaths in the world. Thus, this review article aims at exploring and proposed hypotheses with respect to the possibility that RA can be a promising and alternative compound to be used as an adjuvant in melanoma treatment, acting on purinergic signaling. The scarcity of articles evidencing the action of this compound in this signaling pathway requires further studies. Considering diverse evidence found in the literature, we hypothesize that RA can be an effective candidate for the treatment of CM acting as a modulating molecule of purinergic cellular pathway through P2X7 blocking, mitigating the Warburg effect, and as antagonic molecule of the P2Y12 receptor, reducing the formation of adhesive molecules that prevent adherence in tumor cells. In this way, our proposals for CM treatment based on targeting purinergic signaling permeate the integral practice, going from intracell to extracell. Undoubtedly, much is still to be discovered and elucidated about this promising compound, this paper being an interesting work baseline to support more research studies.

Redox-Related Proteins in Melanoma Progression

Melanoma is the most aggressive type of skin cancer. Despite the available therapies, the minimum residual disease is still refractory. Reactive oxygen and nitrogen species (ROS and RNS) play a dual role in melanoma, where redox imbalance is involved from initiation to metastasis and resistance. Redox proteins modulate the disease by controlling ROS/RNS levels in immune response, proliferation, invasion, and relapse. Chemotherapeutics such as BRAF and MEK inhibitors promote oxidative stress, but high ROS/RNS amounts with a robust antioxidant system allow cells to be adaptive and cooperate to non-toxic levels. These proteins could act as biomarkers and possible targets. By understanding the complex mechanisms involved in adaptation and searching for new targets to make cells more susceptible to treatment, the disease might be overcome. Therefore, exploring the role of redox-sensitive proteins and the modulation of redox homeostasis may provide clues to new therapies. This study analyzes information obtained from a public cohort of melanoma patients about the expression of redox-generating and detoxifying proteins in melanoma during the disease stages, genetic alterations, and overall patient survival status. According to our analysis, 66% of the isoforms presented differential expression on melanoma progression: NOS2, SOD1, NOX4, PRX3, PXDN and GPX1 are increased during melanoma progression, while CAT, GPX3, TXNIP, and PRX2 are decreased. Besides, the stage of the disease could influence the result as well. The levels of PRX1, PRX5 and PRX6 can be increased or decreased depending on the stage. We showed that all analyzed isoforms presented some genetic alteration on the gene, most of them (78%) for increased mRNA expression. Interestingly, 34% of all melanoma patients showed genetic alterations on TRX1, most for decreased mRNA expression. Additionally, 15% of the isoforms showed a significant reduction in overall patient survival status for an altered group (PRX3, PRX5, TR2, and GR) and the unaltered group (NOX4). Although no such specific antioxidant therapy is approved for melanoma yet, inhibitors or mimetics of these redox-sensitive proteins have achieved very promising results. We foresee that forthcoming investigations on the modulation of these proteins will bring significant advances for cancer therapy.

Assessing Causal Associations of Atopic Dermatitis With Heart Failure and Other Cardiovascular Outcomes: A Mendelian Randomization Study

Background and Aims

Observational epidemiological studies have suggested that atopic dermatitis (AD) was associated with an increased risk of cardiovascular diseases (CVDs). However, causality remains to be established. In the present study, Mendelian randomization (MR) analyses were used to evaluate whether AD and CVDs are causally associated.

Methods

This study was based on summary statistics of genome-wide association studies (GWASs) for a set of cardiovascular outcomes including heart failure (HF), coronary artery disease (CAD), myocardial infarction (MI), atrial fibrillation (AF), stroke, and stroke subtypes. A total of 19 independent single nucleotide polymorphisms associated with AD were identified at a genome-wide significance threshold (P < 5 × 10^-8) based on a large GWAS meta-analysis. MR estimates were pooled using the inverse variance weighted method. Complementary analyses further evaluated the robustness of the results.

Results

Genetically determined AD was causally associated with HF [odds ratio (OR), 1.07; 95% confidence interval (CI), 1.03-1.10; P = 1.11 × 10^-4]. However, there was no causal association between AD and the risk of AF, CAD, MI, stroke, and stroke subtypes. Complementary analyses returned similar results. No horizontal pleiotropy was found.

Conclusion

This MR study provided evidence to support that AD exerted an effect contributing to HF. No significant associations were found for other cardiovascular outcomes. The study suggested that prevention and early diagnosis of AD may help prevent HF. Improved awareness of these associations is warranted for better management of CVDs in the future.

Involvement of microRNAs as a Response to Phototherapy and Photodynamic Therapy: A Literature Review

The current knowledge about the mechanisms of action of light-based treatments (chiefly photodynamic therapy and phototherapy) in skin diseases leans to the possible involvement of epigenetic and oxidative stress mechanisms. To better understand and exploit, to the fullest, these relatively safe and reproducible treatments, several studies have focused on miRNAs, small non-encoding RNAs (22–24 nucleotides), after light-based treatments. The current narrative review focused on 25 articles. A meta-analysis was not deemed appropriate. The results gather the most recurrent skin-related miRNAs up- or downregulated after light treatment. Five of these, miR-21, -29, -125, -145 and -155, are either the most consistently related to efficacy/resistance to treatment or identified as helpful diagnostic tools. A specific class of miRNAs (angioMIRs) requires further studies. Future treatments and imaging techniques could benefit greatly from the use of antagomirs as a possible co-adjuvant therapy along with light-based treatments.

Therapies with Antioxidant Potential in Psoriasis, Vitiligo, and Lichen Planus

Oxidative stress plays an important pathogenetic role in many chronic inflammatory diseases, including those of dermatological interest. In particular, regarding psoriasis, vitiligo, and lichen planus, excess reactive oxygen species and a decline in endogenous antioxidant systems are observed. In this regard, treatments with antioxidant properties could be appropriate therapeutic options. To date, clinical trials in dermatology on these treatments are limited. We reviewed the available studies on the efficacy of antioxidant therapies in psoriasis, vitiligo, and lichen planus. The role of herbal derivatives, vitamins, and trace elements was analyzed. The antioxidant properties of conventional therapies were also evaluated. Data from the literature suggest that antioxidants might be useful, but available studies on this topic are limited, heterogeneous, not completely standardized, and on small populations. Furthermore, in most cases, antioxidants alone are unable to induce significant clinical changes, except perhaps in mild forms, and must be used in conjunction with standard drug treatments to achieve measurable results. Further studies need to be conducted, considering larger populations and using internationally validated scales, in order to compare the results and clinical efficacy.

Inhibitory effects of cynaropicrin on human melanoma progression by targeting MAPK, NF-κB, and Nrf-2 signaling pathways in vitro

Malignant melanoma is the deadliest skin cancer, due to its propensity to metastasize. MAPKs and NF-κB pathways are constitutively activated in melanoma and promote cell proliferation, cell invasion, metastasis formation, and resistance to therapeutic regimens. Thus, they represent potential targets for melanoma prevention and treatment. Phytochemicals are gaining considerable attention for the management of melanoma because of their several cellular and molecular targets. A screening of a small library of sesquiterpenes lactones selected cynaropicrin, isolated from the aerial parts of Centaurea drabifolia subsp. detonsa, for its potential anticancer effect against melanoma cells. Treatment of human melanoma cells A375 with cynaropicrin resulted in inhibition of cell proliferation and induction of caspase-3-dependent apoptosis. Furthermore, cynaropicrin reduced several cellular malignant features such migration, invasion, and colonies formation through the inhibition of ERK1/2 and NF-κB activity. Cynaropicrin was able to reduce intracellular reactive oxygen species generation, which are involved in all the stages of carcinogenesis. Indeed, cynaropicrin increased the expression of several antioxidant genes, such as glutamate-cysteine ligase and heme oxygenase-1, by promoting the activation of the transcription factor Nrf-2. In conclusion, our results individuate cynaropicrin as a potential adjuvant chemotherapeutic agent for melanoma by targeting several protumorigenic signaling pathways.

The impact of the co-exposure of melanoma cells to chlorogenic acid and a moderate-strength static magnetic field

A static magnetic field (SMF) or the bioactive compounds that are found in foods are potential agents that can be used to support cancer therapy. Therefore, the aim of our study was to assess the impact of the SMF that are induced by neodymium magnets on the culture growth and antioxidant status of melanoma cells that had been treated with chlorogenic acid (CGA). The melanoma cells, the control and those that had been treated with CGA, were put in special magnetic test chambers that generated a 0.7 T magnetic field. The mRNA levels of the antioxidant enzymes were analyzed using RT-qPCR. The activity of SOD, GPx, and CAT was measured in the cell lysates. While the expression and activity of the antioxidant enzymes was inhibited relative to the untreated cells as a result of the CGA treatment (1 mmol/L), it was not after the CGA treatment in combination with an SMF. The demonstrated cytotoxicity of CGA (1 mmol/L) and its inhibition of the antioxidant enzymes suggests the usefulness of phenolic compounds as a supporting pharmacological treatment for melanoma. PRACTICAL APPLICATIONS: Phenolic acids and their derivatives, which are the bioactive components of the human diet, are signal molecules that transfer information from the external environment that affects the level of gene expression in cells. This study suggests the usefulness of phenolic compounds as a supporting pharmacological treatment for melanoma and seems to be important for the development of experimental oncology.

Adaptive redox homeostasis in cutaneous melanoma

Cutaneous melanoma is the most aggressive type of skin cancer. Although cutaneous melanoma accounts for a minority of all types of skin cancer, it causes the greatest number of skin cancer related deaths worldwide. Oxidative stress and redox homeostasis have been shown to be involved at each stage of a malignant melanocyte transformation, called melanomagenesis, as well as during drug resistance. Reactive oxygen species (ROS) play an important and diverse role that regulate many aspects of skin cell behaviors ranging from proliferation and stemness, to oxidative damage and cell death. On the other hand, antioxidants are associated with melanoma spread and metastasis. Overall, the contribution of redox homeostasis to melanoma development and progression is controversial and highly complex. The aim of this study is to examine the association between redox homeostasis and the melanomagenic process. To this purpose we are presenting what is currently known about the role of ROS in melanoma initiation and progression. In addition, we are discussing the role of antioxidant mechanisms during the spread of the disease and in cases of melanoma drug resistance. Although challenging, targeting redox homeostasis in melanoma progression remains to be a promising therapeutic approach, especially valid during melanoma drug resistance.

Plasma Treatment Limits Human Melanoma Spheroid Growth and Metastasis Independent of the Ambient Gas Composition

Simple Summary

Despite recent advances in therapeutic options, melanoma remains a deadly disease with a poor prognosis. Physical gas plasma has been proposed as a promising technology for the treatment of melanoma. This study aimed to develop and investigate a convenient test system based on three-dimensional cell cultures (spheroids) of two melanoma cell lines in response to physical gas plasma. The experimental approach combined high-content imaging technology and different gas plasma treatment modalities (direct and indirect, gas compositions). Our results revealed that plasma treatment was toxic for both cell lines predominantly dependent on the treatment time. Furthermore, we addressed the question of safety and morphological changes in response to physical gas plasma exposure and found no support for metastatic progression. Treatment with physical gas plasma effectively limited the growth of human 3D melanoma spheroids and provided a versatile test system for more in vivo-like tumor tissue.

Abstract

Melanoma skin cancer is still a deadly disease despite recent advances in therapy. Previous studies have suggested medical plasma technology as a promising modality for melanoma treatment. However, the efficacy of plasmas operated under different ambient air conditions and the comparison of direct and indirect plasma treatments are mostly unexplored for this tumor entity. Moreover, exactly how plasma treatment affects melanoma metastasis has still not been explained. Using 3D tumor spheroid models and high-content imaging technology, we addressed these questions by utilizing one metastatic and one non-metastatic human melanoma cell line targeted with an argon plasma jet. Plasma treatment was toxic in both cell lines. Modulating the oxygen and nitrogen ambient air composition (100/0, 75/25, 50/50, 25/75, and 0/100) gave similar toxicity and reduced the spheroid growth for all conditions. This was the case for both direct and indirect treatments, with the former showing a treatment time-dependent response while the latter resulted in cytotoxicity with the longest treatment time investigated. Live-cell imaging of in-gel cultured spheroids indicated that plasma treatment did not enhance metastasis, and flow cytometry showed a significant modulation of S100A4 but not in any of the five other metastasis-related markers (β-catenin, E-cadherin, LEF1, SLUG, and ZEB1) investigated.

Staging Melanocytic Skin Neoplasms Using High-Level Pixel-Based Features

The formation of malignant neoplasm can be seen as deterioration of a pre-malignant skin neoplasm in its functionality and structure. Distinguishing melanocytic skin neoplasms is a challenging task due to their high visual similarity with different types of lesions and the intra-structural variants of melanocytic neoplasms. Besides, there is a high visual likeliness level between different lesion types with inhomogeneous features and fuzzy boundaries. The abnormal growth of melanocytic neoplasms takes various forms from uniform typical pigment network to irregular atypical shape, which can be described by border irregularity of melanocyte lesion image. This work proposes analytical reasoning for the human-observable phenomenon as a high-level feature to determine the neoplasm growth phase using a novel pixel-based feature space. The pixel-based feature space, which is comprised of high-level features and other color and texture features, are fed into the classifier to classify different melanocyte neoplasm phases. The proposed system was evaluated on the PH2 dermoscopic images benchmark dataset. It achieved an average accuracy of 95.1% using a support vector machine (SVM) classifier with the radial basis function (RBF) kernel. Furthermore, it reached an average Disc similarity coefficient (DSC) of 95.1%, an area under the curve (AUC) of 96.9%, and a sensitivity of 99%. The results of the proposed system outperform the results of other state-of-the-art multiclass techniques.

Metabolic rewiring in melanoma drug-resistant cells

Several evidences indicate that melanoma, one of the deadliest types of cancer, presents the ability to transiently shift its phenotype under treatment or microenvironmental pressure to an invasive and treatment-resistant phenotype, which is characterized by cells with slow division cycle (also called slow-cycling cells) and high-OXPHOS metabolism. Many cellular marks have been proposed to track this phenotype, such as the expression levels of the master regulator of melanocyte differentiation (MITF) and the epigenetic factor JARID1B. It seems that the slow-cycling phenotype does not necessarily present a single gene expression signature. However, many lines of evidence lead to a common metabolic rewiring process in resistant cells that activates mitochondrial metabolism and changes the mitochondrial network morphology. Here, we propose that mitochondria-targeted drugs could increase not only the efficiency of target therapy, bypassing the dynamics between fast-cycling and slow-cycling, but also the sensitivity to immunotherapy by modulation of the melanoma microenvironment.

Oxidative Stress and Photodynamic Therapy of Skin Cancers: Mechanisms, Challenges and Promising Developments

Ultraviolet radiation is one of the most pervasive environmental interactions with humans. Chronic ultraviolet irradiation increases the danger of skin carcinogenesis. Probably, oxidative stress is the most important mechanism by which ultraviolet radiation implements its damaging effects on normal cells. However, notwithstanding the data referring to the negative effects exerted by light radiation and oxidative stress on carcinogenesis, both factors are used in the treatment of skin cancer. Photodynamic therapy (PDT) consists of the administration of a photosensitiser, which undergoes excitation after suitable irradiation emitted from a light source and generates reactive oxygen species. Oxidative stress causes a condition in which cellular components, including DNA, proteins, and lipids, are oxidised and injured. Antitumor effects result from the combination of direct tumour cell photodamage, the destruction of tumour vasculature and the activation of an immune response. In this review, we report the data present in literature dealing with the main signalling molecular pathways modified by oxidative stress after photodynamic therapy to target skin cancer cells. Moreover, we describe the progress made in the design of anti-skin cancer photosensitisers, and the new possibilities of increasing the efficacy of PDT via the use of molecules capable of developing a synergistic antineoplastic action.

Overcoming Intrinsic Doxorubicin Resistance in Melanoma by Anti-Angiogenic and Anti-Metastatic Effects of Liposomal Prednisolone Phosphate on Tumor Microenvironment

Regardless of recent progress, melanoma is very difficult to treat, mainly due to the drug resistance modulated by tumor cells as well as by the tumor microenvironment (TME). Among the immune cells recruited at the tumor site, tumor associated macrophages (TAMs) are the most abundant, promoting important tumorigenic processes: angiogenesis, inflammation and invasiveness. Furthermore, it has been shown that TAMs are involved in mediating the drug resistance of melanoma cells. Thus, in the present study, we used liposomal formulation of prednisolone disodium phosphate (LCL-PLP) to inhibit the protumor function of TAMs with the aim to sensitize the melanoma cells to the cytotoxic drug doxorubicin (DOX) to which human melanoma has intrinsic resistance. Consequently, we evaluated the in vivo effects of the concomitant administration of LCL-PLP and liposomal formulation of DOX (LCL-DOX) on B16.F10 melanoma growth and on the production of key molecular markers for tumor development. Our results demonstrated that the concomitant administration of LCL-PLP and LCL-DOX induced a strong inhibition of tumor growth, primarily by inhibiting TAMs-mediated angiogenesis as well as the tumor production of MMP-2 and AP-1. Moreover, our data suggested that the combined therapy also affected TME as the number of infiltrated macrophages in melanoma microenvironment was reduced significantly.

Long non-coding RNA GAS5 accelerates oxidative stress in melanoma cells by rescuing EZH2-mediated CDKN1C downregulation

Background

The significance of long non-coding RNAs (lncRNAs) in mediating oxidative stress of cancers has been implicated recently. This study proposed a potential therapeutic target lncRNA growth arrest-specific transcript 5 (GAS5) for melanoma, due to its crucial role in oxidative stress and apoptosis of melanoma cells by regulating the enhancer of zeste homolog 2 (EZH2)-mediated CDKN1C expression.

Methods

The lncRNA GAS5 expression pattern was examined in melanoma tissues and cells. The correlation of lncRNA GAS5, EZH2, and CDKN1C with survival rate of melanoma patients was analyzed. In melanoma cell lines, lncRNA GAS5 expression was overexpressed or knocked down to clarify its effects on cell viability, apoptosis, and oxidative stress. The interaction between lncRNA GAS5 and EZH2 was examined by RIP and RNA pull-down assays followed by verification of the target relationship between EZH2 and CDKN1C.

Results

High expression of EZH2 and poor expression of lncRNA GAS5 and CDKN1C was observed in melanoma tissues and found to be correlated with the reduction in survival expectancy of melanoma patients. Overexpression of lncRNA GAS5 or CDKN1C or EZH2 knockdown could inhibit cell viability but enhance melanoma cell apoptosis and oxidative stress. Importantly, lncRNA GAS5 attenuated EZH2 expression by recruiting E2F4 to the EZH2 promoter region and knockdown of EZH2 upregulated CDKN1C expression by inhibiting the H3K27me3.

Conclusion

The evidence provided by our study highlighted the involvement of lncRNA GAS5 in the translational suppression of EZH2 as well as the upregulation of CDKN1C, resulting in the promotion of melanoma cell apoptosis and oxidative stress.

Oxidative Stress and Atopic Dermatitis

Atopic dermatitis is a common chronic/chronically relapsing inflammatory skin disease, with increasing worldwide prevalence. Etiopathogenesis is complex and multifactorial, with a mix of genetic, immunological and environmental aspects. Like in other chronic inflammatory diseases, oxidative stress plays an important pathogenetic role. We reviewed in vivo research studies on humans about oxidative stress and atopic dermatitis. Although sometimes contrasting, overall, they suggest that oxidative stress may have a significant role in atopic dermatitis, but our understanding is still incomplete, at least concerning in vivo data, because of limitations of available literature. Research consists of 33 papers published in 28 years, was not always performed on large study populations, represents a limited number of countries and ethnicities-not always in proportion to their size-and is scattered over multiple papers that, in the majority of cases, cannot be pooled and/or compared because many biomarkers were studied, in different tissues and with different methods. Further, larger studies appear warranted and necessary to shed more light on this aspect of atopic dermatitis, which is important not only to improve our understanding of this disease, but also for potential clinical and therapeutic implications.

Association between genetic polymorphisms of glutathione S-transferase M1/T1 and psoriasis in a population from the area of the strict of messina (Southern Italy)

Glutathione S-transferases (GST) are antioxidant enzymes with frequent genetic polymorphisms. Homozygosis for gene deletion ("null" genotype) of GSTM1 and GSTT1, causing decrease of the antioxidant potential of the organism, is frequent, with variable frequency in different ethnic contexts. Although oxidative stress notoriously plays a role in the pathogenesis of psoriasis, few studies exist on the association between GSTM1/GSTT1 genotype and psoriasis, with different results. We aimed to assess the frequency of GSTM1/GSTT1 polymorphisms in Southern Italian psoriatic patients and controls and investigate the association of the GSTM1/GSTT1 genotype with individual and disease parameters. To this aim, the GSTM1/GSTT1 genotype of 148 psoriatic patients and 148 age- and sex-matched controls was defined by PCR on oral mucosa cells. GSTT1 null was associated with psoriasis (55.4% of patients vs. 25% of controls, p = 9.58 × 10^-8, odds ratio 3.73), while GSTM1 null was not. The GSTM1/GSTT1 "double null" genotype conferred an even higher odds ratio for psoriasis (5.94). The association between psoriasis and GSTT1 null was stronger in women (54.1% of patients vs. 19.7% of controls, p = 8.13 × 10^-5) than in men (56.3% of patients vs. 28.7% of controls, p = 0.0002). No association was found between GSTM1/GSTT1 genotype and psoriasis severity, age of onset or comorbidities (psoriatic arthritis, metabolic syndrome). The remarkable differences among the few available data on the association between GSTM1/GSTT1 polymorphisms and psoriasis suggest the need for further studies, on different and larger populations, to improve knowledge on the pathogenesis of psoriasis and possibly provide more precise and personalised prevention and treatment in the future.

Emerging Perspective: Role of Increased ROS and Redox Imbalance in Skin Carcinogenesis

Strategies to battle malignant tumors have always been a dynamic research endeavour. Although various vehicles (e.g., chemotherapeutic therapy, radiotherapy, surgical resection, etc.) are used for skin cancer management, they mostly remain unsatisfactory due to the complex mechanism of carcinogenesis. Increasing evidence indicates that redox imbalance and aberrant reactive oxygen species (ROS) are closely implicated in the oncogenesis of skin cancer. When ROS production goes beyond their clearance, excessive or accumulated ROS could disrupt redox balance, induce oxidative stress, and activate the altered ROS signals. These would damage cellular DNA, proteins, and lipids, further leading to gene mutation, cell hyperproliferation, and fatal lesions in cells that contribute to carcinogenesis in the skin. It has been known that ROS-mediated skin carcinogenesis involves multiple ways, including modulating related signaling pathways, changing cell metabolism, and causing the instability of the genome and epigenome. Nevertheless, the exact role of ROS in skin cancer has not been thoroughly elucidated. In spite of ROS inducing skin carcinogenesis, toxic-dose ROS could trigger cell death/apoptosis and, therefore, may be an efficient therapeutic tool to battle skin cancer. Considering the dual role of ROS in the carcinogenesis and treatment of skin cancer, it would be essential to clarify the relationship between ROS and skin cancer. Thus, in this review, we get the related data together to seek the connection between ROS and skin carcinogenesis. Besides, strategies basing on ROS to fight skin cancer are discussed.

Specific Urinary Metabolites in Malignant Melanoma

Background and objectives: Melanin, which has a confirmed role in melanoma cell behaviour, is formed in the process of melanogenesis and is synthesized from tryptophan, L-tyrosine and their metabolites. All these metabolites are easily detectable by chromatography in urine. Materials and Methods: Urine samples of 133 individuals (82 malignant melanoma patients and 51 healthy controls) were analysed by reversed-phase high-performance liquid chromatography (RP-HPLC). The diagnosis of malignant melanoma was confirmed histologically. Results: Chromatograms of melanoma patients showed increased levels of 5,6-dihydroxyindole-2-carboxylic acid, vanilmandelic acid, homovanilic acid, tryptophan, 5-hydroxyindole-3-acetic acid, and indoxyl sulphate compared to healthy controls. Concentration of indoxyl sulphate, homovanilic acid and tryptophan were significantly increased even in the low clinical stage 0 of the disease (indoxyl sulphate, homovanilic acid and tryptophan in patients with clinical stage 0 vs. controls expressed as medium/ interquartile range in µmol/mmol creatinine: 28.37/15.30 vs. 5.00/6.91; 47.97/33.08 vs. 7.33/21.25; and 16.38/15.98 vs. 3.46/6.22, respectively). Conclusions: HPLC detection of metabolites of L-tyrosine and tryptophan in the urine of melanoma patients may play a significant role in diagnostics as well as a therapeutic strategy of melanoma cancer.