Coriolus versicolor-derived protein-bound polysaccharides trigger the caspase-independent cell death pathway in amelanotic but not melanotic melanoma cells

In vitro treatment of triple-negative breast cancer cells with an extract from the Coriolus versicolor mushroom changes macrophage properties related to tumourigenesis

Macrophages, the most abundant cells that participate in tumour progression, are the subject of a number of anticancer therapy approaches. Our previous results revealed that an extract of the fungus Coriolus versicolor (CV) has anti-cancer and immunomodulatory properties. The aim of the present study was to investigate whether CV extract-treated triple-negative breast cancer (TNBC) cells can release factors that can reprogram macrophages from pro-tumourigenic to anti-cancer subtypes. RAW 264.7 macrophages were cultured in a conditioned medium (CM) from non-treated 4T1 breast cancer cells (CM-NT) or CV extract-stimulated cells (CM-CV). After treatment, the following macrophage properties were evaluated: cell viability; M1/M2 phenotype (enzyme activities: iNOS and arginase 1; and expression of CD molecules: CD80 and CD163); cytokine concentrations: IL-6, TNF-α, IL-10, TGF-β, MCP-1 and VEGF; migration level; and ROS production. The results revealed that, compared with normal cells, TNBC cells stimulated with CV extract create a microenvironment that promotes a decrease in macrophage viability and migration, intracellular ROS production, and pro-angiogenic cytokine production (VEGF and MCP-1). Moreover, CM-CV decreased the expression of M2 macrophage markers (arginase 1 and CD163; IL-10 and TGF-β) but upregulated the expression of M1 cell markers (iNOS and CD80; IL-6 and TNF-α). We concluded that CV extract modifies the tumour microenvironment and changes macrophage polarisation toward functioning as an anti-tumour agent. Therefore, it is promising to use in the treatment of TNBC-associated macrophages.

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.

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

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

A comprehensive review on the health benefits, phytochemicals, and enzymatic constituents for potential therapeutic and industrial applications of Turkey tail mushrooms

This comprehensive literature review delves into the multifaceted attributes of Trametes versicolor, commonly known as turkey tail mushroom. The turkey tail mushroom stands as a noteworthy source of diverse bioactive compounds with potent health benefits. This review offers a contemporary synthesis of its phytochemical constituents and their multifaceted impacts on human health. The mushroom's intricate composition, encompassing polysaccharides, phenols, and triterpenes, underpins its remarkable therapeutic potential. Focusing on key attributes such as anti-cancer, anti-microbial, and immunomodulatory activities, this review delves into the intricate mechanisms by which the turkey tail mushroom exerts its effects. In addition, the exploration extends to the enzymatic constituents inherent in the mushroom and their industrial significance. Mechanisms of action for both phytochemicals and enzymes are studied, providing a well-rounded understanding of their roles in conferring therapeutic and industrial benefits. This synthesis of research aims to provide an up-to-date perspective on turkey tail mushrooms' versatile applications. By intertwining the exploration of health benefits and enzymatic constituents, this review offers insights into the potential of harnessing this natural resource for innovative therapeutic strategies and industrial applications. Overall, it contributes to the advancement of knowledge and utilisation of turkey tail mushrooms' diverse properties for human health and industrial progress.

The advancement of polysaccharides in disease modulation: Multifaceted regulation of programmed cell death

Programmed cell death (PCD), also known as regulatory cell death (RCD), is a process that occurs in all organisms and is closely linked to both normal physiological processes and disease states. Various signaling pathways, such as TP53, KRAS, NOTCH, hypoxia, and metabolic reprogramming, have been found to regulate RCD. Polysaccharides, which are essential natural products, have been the subject of extensive research in the fields of food, nutrition, and medicine due to their wide range of pharmacological effects. Studies have shown that polysaccharides have biological activities and the potential to target signal transduction pathways for the treatment of diseases. This paper provides a review of the mechanisms through which polysaccharides exert their therapeutic effects at different levels and explores the relationship between different types of RCD and human diseases. The aim of this review is to provide a theoretical basis for the further clinical use and application of polysaccharide bioactivities.

The combination of pro-oxidative acting vanicosides and GLUT1 inhibitor (WZB117) exerts a synergistic cytotoxic effect against melanoma cells

Vanicosides A and B isolated from Reynoutria sachalinensis rhizomes are disaccharide phenylpropanoid esters with proven antioxidant activity. Our earlier study showed the cytotoxic activity of vanicosides against melanoma cells, but the mechanism of cell death has not been elucidated. Based on the chemical structure of vanicosides, we proposed that they may induce cell death by generating reactive oxygen species (ROS) into melanoma cells. Moreover, the glucose molecule in their structure can affect the glucose transporters (GLUTs), upregulated in cancer cells. The A375 (melanotic) and C32 (amelanotic) melanoma cell lines were applied. Cell viability assay and ROS-Glo™ assay were performed before and after blocking of Glucose Transporter Type 1 (GLUT1) by WZB117. Fibroblasts and the SKOV-3 line were included in the study to test selectivity in the action of vanicosides and help to elucidate the mechanism of action. Upon incubation with vanicosides, high production of ROS occured, especially inside C32 cells, which was significantly reduced after GLUT-1 blocking. The A375 cells produced less ROS. Melanoma cells were simillary sensitive to the cytotoxic effects of vanicosides, which was clearly enhanced when vanicosides were used together with the WZB117 (GLUT1 inhibitor). The SKOV-3 line and the fibroblasts showed much less sensitivity to the cytotoxicity of vanicosides, also used together with WZB117. Moreover, no significant ROS formation was observed in these lines. The study proved that vanicosides generate ROS inside melanoma cells. These findings suggest that the combination of pro-oxidative acting vanicosides and GLUT1 inhibitors exerts a synergistic cytotoxic effect on melanoma cells.

Polysaccharides from Hemerocallis citrina Baroni Inhibit the Growth of Hepatocellular Carcinoma Cells by Regulating the Wnt/β-Catenin Pathway

Hemerocallis citrina Baroni is an edible plant with anti-inflammatory, antidepressant, and anticancer activities. However, studies on H. citrina polysaccharides are limited. In this study, a polysaccharide named HcBPS2 was isolated and purified from H. citrina. Monosaccharide component analysis showed that HcBPS2 was composed of rhamnose, arabinose, galactose, glucose, xylose, mannose, galacturonic acid, and glucuronic acid. Notably, HcBPS2 significantly inhibited human hepatoma cell proliferation, but had little effect on human normal liver cells (HL-7702). Mechanism investigations indicated HcBPS2 suppressed human hepatoma cell growth through the induction of G2/M phase arrest and mitochondria-dependent apoptosis in human hepatoma cells. In addition, the data revealed that HcBPS2 treatment led to the inactivation of Wnt/β-catenin signaling, which then gave rise to cell cycle arrest and apoptosis in human hepatoma cancer cells. Collectively, these findings suggested that HcBPS2 may serve as a therapeutic agent against liver cancer.

COVID-19 and Cancer Diseases-The Potential of Coriolus versicolor Mushroom to Combat Global Health Challenges

Coriolus versicolor (CV) is a common species from the Polyporaceae family that has been used in traditional Chinese herbal medicine for over 2000 years. Among well-described and most active compounds identified in CV are polysaccharopeptides, such as polysaccharide peptide (PSP) and Polysaccharide-K (PSK, krestin), which, in some countries, are already used as an adjuvant agent in cancer therapy. In this paper, research advances in the field of anti-cancer and anti-viral action of CV are analyzed. The results of data obtained in in vitro and in vivo studies using animal models as well as in clinical research trials have been discussed. The present update provides a brief overview regarding the immunomodulatory effects of CV. A particular focus has been given to the mechanisms of direct effects of CV on cancer cells and angiogenesis. A potential use of CV compounds in anti-viral treatment, including therapy against COVID-19 disease, has also been analyzed based on the most recent literature. Additionally, the significance of fever in viral infection and cancer has been debated, providing evidence that CV affects this phenomenon.

Polysaccharides as antioxidants and prooxidants in managing the double-edged sword of reactive oxygen species

Polysaccharides, a class of naturally occurring carbohydrates, were widely presented in animals, plants, and microorganisms. Recently, health benefits of polysaccharides have attracted much attention due to their unique characteristics in reactive oxygen species (ROS) management. ROS, by-products of aerobic metabolism linked to food consumption, exhibited a dual role in protecting cells and fostering pathogenesis collectively termed double-edged sword. Some interesting studies reported that polysaccharides could behave as prooxidants under certain conditions, besides antioxidant capacities. Potentiation of the bright side of ROS could contribute to the host defense that was vitally important for the polysaccharides acting as biological response modifiers. Correspondingly, disease prevention of polysaccharides linked to the management of ROS production was systematically described and discussed in this review. Furthermore, major challenges and future prospects were presented, aiming to provide new insight into applying polysaccharides as functional food ingredients and medicine.

The mycelium of the Trametes versicolor synn. Coriolus versicolor (Turkey tail mushroom) exhibit anti-melanoma activity in vitro

Melanoma is one of the most aggressive forms of skin cancer and is characterized by high metastatic potential. Despite improvements in early diagnosis and treatment, the mortality rate among metastatic melanoma patients continues to represent a significant clinical challenge. Therefore, it is imperative that we search for new forms of treatment. Trametes versicolor is a mushroom commonly used in Chinese traditional medicine due to its numerous beneficial properties. In the present work, we demonstrate T. versicolor fruiting body and mycelium ethanol extracts exhibit potent cytotoxic activity towards A375 (IC₅₀ = 663.3 and 114.5 µg/mL respectively) and SK-MEL-5 (IC₅₀ = 358.4 and 88.6 µg/mL respectively) human melanoma cell lines. Further studies revealed that T. versicolor mycelium extract induced apoptotic cell death and poly (ADP-ribose) polymerase cleavage, upregulated the expression of autophagy-associated marker LC3-II, increased the presentation of major histocompatibility complex II and expression of programmed death-ligand receptor, and inhibited cell migration in SK-MEL-5 cells. Therefore, our present findings highlight the therapeutic potential of T. versicolor mycelium extract for the treatment of melanoma and merit further study.

Exploring the Bioactive Mycocompounds (Fungal Compounds) of Selected Medicinal Mushrooms and Their Potentials against HPV Infection and Associated Cancer in Humans

Medicinal mushrooms have been used as a medicinal tool for many centuries and, nowadays, are used in the prevention and therapy of various diseases, including as an adjunct to cancer treatment. It is estimated that 14-16% of global cancer cases are caused by infectious events; one well-known infectious agent that leads to cancer is the human papillomavirus (HPV). HPV is responsible for more than 99.7% of cervical cancer cases and also may play a role in vaginal, vulvar, penile, anal, rectal, and oropharyngeal carcinogenesis. Coriolus versicolor, a basidiomycetes class mushroom, consists of glycoproteins called polysaccharide-K (PSK) and polysaccharopeptide (PSP), which are mainly responsible for its effectiveness in the fight against a variety of cancers. Its beneficial effect lies in its ability to arrest different phases of the cell cycle, immunomodulation or induction of apoptosis. Coriolus versicolor extractcan reduces BCL-2 expression or increases the expression of p53 tumour suppressor genes in breast tumour cell lines. Inhibition of proliferation was also demonstrated with HeLa cells, while cervical cytology abnormalities improved in patients who locally applied Coriolus versicolor-based vaginal gel. Coriolus versicolor extract itself, and also its combination with another medicinal mushroom, Ganoderma lucidum, leads to improved HPV clearance in HPV cervical or oral-positive patients. Medicinal mushrooms can also increase the effectiveness of vaccination. This review considers the use of medicinal mushrooms as a suitable adjunct to the treatment of many cancers or precanceroses, including those caused by the HPV virus.

Microbial polysaccharides: An emerging family of natural biomaterials for cancer therapy and diagnostics

Microbial polysaccharides (MPs) offer immense diversity in structural and functional properties. They are extensively used in advance biomedical science owing to their superior biodegradability, hemocompatibility, and capability to imitate the natural extracellular matrix microenvironment. Ease in tailoring, inherent bio-activity, distinct mucoadhesiveness, ability to absorb hydrophobic drugs, and plentiful availability of MPs make them prolific green biomaterials to overcome the significant constraints of cancer chemotherapeutics. Many studies have demonstrated their application to obstruct tumor development and extend survival through immune activation, apoptosis induction, and cell cycle arrest by MPs. Synoptic investigations of MPs are compulsory to decode applied basics in recent inclinations towards cancer regimens. The current review focuses on the anticancer properties of commercially available and newly explored MPs, and outlines their direct and indirect mode of action. The review also highlights cutting-edge MPs-based drug delivery systems to augment the specificity and efficiency of available chemotherapeutics, as well as their emerging role in theranostics.

A Review of Development and Utilization for Edible Fungal Polysaccharides: Extraction, Chemical Characteristics, and Bioactivities

Edible fungi, commonly known as mushrooms, are precious medicinal and edible homologous gifts from nature to us. Because of their distinctive flavor and exceptional nutritional and medicinal value, they have been a frequent visitor to people’s dining tables and have become a hot star in the healthcare, pharmaceutical, and cosmetics industries. Edible fungal polysaccharides (EFPs) are an essential nutrient for edible fungi to exert bioactivity. They have attracted much attention because of their antioxidant, immunomodulatory, antitumor, hypoglycemic, and hypolipidemic bioactivities. As a result, EFPs have demonstrated outstanding potential over the past few decades in various disciplines, including molecular biology, immunology, biotechnology, and pharmaceutical chemistry. However, the complexity of EFPs and the significant impact of mushroom variety and extraction techniques on their bioactivities prevents a complete investigation of their biological features. Therefore, the authors of this paper thoroughly reviewed the comparison of different extraction methods of EFPs and their advantages and disadvantages. In addition, the molecular weight, monosaccharide composition, and glycosidic bond type and backbone structure of EFPs are described in detail. Moreover, the in vitro and in vivo bioactivities of EFPs extracted by different methods and their potential regulatory mechanisms are summarized. These provide a valuable reference for improving the extraction process of EFPs and their production and development in the pharmaceutical field.

Identification of an endoplasmic reticulum stress-associated gene signature to predict the immune status and prognosis of cutaneous melanoma

Besides protecting normal cells from various internal and external perturbations, endoplasmic reticulum (ER) stress is also directly related to the pathogenesis of cutaneous melanoma (CM). However, due to the lack of specific molecular biomarkers, ER stress has not been considered a novel treatment target for CM. Here, we identified ER stress-related genes involved in the prognosis of CM patients and constructed an effective model for the prognostic prediction of these patients. First, gene expression data of CM and normal skin tissues from the Genotype-Tissue Expression (GTEx) and The Cancer Genome Atlas (TCGA) databases were retrieved to identify differentially expressed ER stress-related genes in CM. Meanwhile, an independent cohort obtained from the Gene Expression Omnibus (GEO) database was used for validation. The ER stress genes (ZBP1, DIABLO, GNLY, FASLG, AURKA, TNFRSF21, and CD40LG) that were associated with CM prognosis were incorporated into our prognostic model. The functional analyses indicated that the prognostic model was correlated with patient survival, gender, and cancer growth. Multivariate and univariate Cox regressions revealed that the constructed model could serve as an independent prognostic factor for CM patients. The pathway enrichment analysis showed that the risk model was enriched in different immunity and cancer progression-associated pathways. Moreover, the signature model was significantly connected with the immune subtypes, infiltration of immune cells, immune microenvironment, as well as tumor stem cells. The gene function analysis revealed that 7 ER stress genes were differentially expressed in CM patients and were significantly associated with prognosis and several antitumor drugs. Overall, our current model presented predictive value for the prognosis of CM patients and can be further used in the development of novel therapeutic strategies for CM.

Current Advancements in Antitumor Properties and Mechanisms of Medicinal Components in Edible Mushrooms

Edible and medicinal fungi, a group of eukaryotic organisms with numerous varieties, including Coriolus versicolor, Ganoderma lucidum, Cordyceps sinensis, Pleurotus ostreatus, and Grifola frondosa, have been demonstrated to possess a board range of pharmaceutical properties, including anti-virus, anti-inflammation, and neuroprotection. Moreover, edible and medicinal fungi have been traditionally consumed as food to provide multiple nutrients and as drugs owing to having the activities of invigorating blood circulation, reinforcing the healthy qi, clearing away heat, and eliminating stasis for thousands of years in China. Malignant tumors, well-known as the second leading cause of death globally, accounted for nearly 10 million deaths in 2020. Thus, in-depth exploration of strategies to prevent and treat cancer is extremely urgent. A variety of studies have reported that the main bioactive components of edible and medicinal fungi, mainly polysaccharides and triterpenoids, exhibit diverse anticancer activities via multiple mechanisms, including inhibition of cell proliferation and metastasis, induction of apoptosis and autophagy, reversing multidrug resistance, and regulation of immune responses, thus suggesting their substantial potential in the prevention and treatment of cancer. Our review summarizes the research progress on the anticancer properties of edible and medicinal fungi and the underlying molecular mechanism, which may offer a better understanding of this field. Additionally, few studies have reported the safety and efficacy of extracts from edible and medicinal fungi, which may limit their clinical application. In summary, there is a need to continue to explore the use of those extracts and to further validate their safety and efficacy.

Necroptosis-associated classification combined with tumor microenvironment characteristic analysis of cutaneous melanoma

Necroptosis is a mode of programmed cell death that overcomes apoptotic resistance. The accurate prognosis of cutaneous melanoma is complicated to predict due to tumor heterogeneity. Necroptosis contributes to the regulation of oncogenesis and cancer immunity. We comprehensively investigated different necroptosis patterns by the non-negative matrix factorization (NMF) clustering analysis and explored the relationships among necroptosis patterns, infiltered immune cells, and tumor microenvironment (TME) scores. Two different necroptosis patterns were identified, and the two clusters could predict prognosis and immune landscape. A four-gene signature was successfully constructed and validated its predictive capability of overall survival (OS) in cutaneous melanoma patients. The prognostic value of the signature was further enhanced by incorporating other independent prognostic factors such as age and clinicopathological stages in a nomogram-based prediction model. Patients with lower risk scores tended to have better OS, higher TME score, immune checkpoints, immunophenoscore (IPS), and lower Tumor Immune Dysfunction and Exclusion (TIDE), which indicated better responses to immunotherapy. In addition, the pigmentation score of the high-risk group was visibly higher than those of the low-risk group. In conclusion, the necroptosis-related signature indicated favorable predictive performance in cutaneous melanoma patients, which provides guidance for immunotherapy and provide novel insights into precision medicine.

The Genetic Basis of Dormancy and Awakening in Cutaneous Metastatic Melanoma

Immune dysregulation, in combination with genetic and epigenetic alterations, induces an excessive proliferation of uncontrolled melanoma cells followed by dissemination of the tumor cells to distant sites, invading organs and creating metastasis. Although immunotherapy, checkpoint inhibitors and molecular targeted therapies have been developed as treatment options for advanced melanoma, there are specific mechanisms by which cancer cells can escape treatment. One of the main factors associated with reduced response to therapy is the ability of residual tumor cells to persist in a dormant state, without proliferation. This comprehensive review aimed at understanding the genetic basis of dormancy/awakening phenomenon in metastatic melanoma will help identify the possible therapeutical strategies that might eliminate melanoma circulating tumor cells (CTCs) or keep them in the dormant state forever, thereby repressing tumor relapse and metastatic spread.

Development and Validation of a Novel Survival Model for Cutaneous Melanoma Based on Necroptosis-Related Genes

Background

Necroptosis is crucial for organismal development and pathogenesis. To date, the role of necroptosis in skin cutaneous melanoma (SKCM) is yet unveiled. In addition, the part of melanin pigmentation was largely neglected in the bioinformatic analysis. In this study, we aimed to construct a novel prognostic model based on necroptosis-related genes and analysis the pigmentation phenotype of patients to provide clinically actionable information for SKCM patients.

Methods

We downloaded the SKCM data from the TCGA and GEO databases in this study and identified the differently expressed and prognostic necroptosis-related genes. Patients’ pigmentation phenotype was evaluated by the GSVA method. Then, using Lasso and Cox regression analysis, a novel prognostic model was constructed based on the intersected genes. The risk score was calculated and the patients were divided into two groups. The survival differences between the two groups were compared using Kaplan-Meier analysis. The ROC analysis was performed and the area under curves was calculated to evaluate the prediction performances of the model. Then, the GO, KEGG and GSEA analyses were performed to elucidate the underlying mechanisms. Differences in the tumor microenvironment, patients’ response to immune checkpoint inhibitors (ICIs) and pigmentation phenotype were analyzed. In order to validate the mRNA expression levels of the selected genes, quantitative real-time PCR (qRT-PCR) was performed.

Results

Altogether, a novel prognostic model based on four genes (BOK, CD14, CYLD and FASLG) was constructed, and patients were classified into high and low-risk groups based on the median risk score. Low-risk group patients showed better survival status. The model showed high accuracy in the training and the validation cohort. Pathway and functional enrichment analysis indicated that immune-related pathways were differently activated in the two groups. In addition, immune cells infiltration patterns and sensitivity of ICIs showed a significant difference between patients from two risk groups. The pigmentation score was positively related to the risk score in pigmentation phenotype analysis.

Conclusion

In conclusion, this study established a novel prognostic model based on necroptosis-related genes and revealed the possible connections between necroptosis and melanin pigmentation. It is expected to provide a reference for clinical treatment.

Melanoma, Melanin, and Melanogenesis: The Yin and Yang Relationship

Melanin pigment plays a critical role in the protection against the harmful effects of ultraviolet radiation and other environmental stressors. It is produced by the enzymatic transformation of L-tyrosine to dopaquinone and subsequent chemical and biochemical reactions resulting in the formation of various 5,6-dihydroxyindole-2-carboxylic acid (DHICA) and 5,6-dihydroxyindole (DHI) oligomers-main constituents of eumelanin, and benzothiazine and benzothiazole units of pheomelanin. The biosynthesis of melanin is regulated by sun exposure and by many hormonal factors at the tissue, cellular, and subcellular levels. While the presence of melanin protects against the development of skin cancers including cutaneous melanoma, its presence may be necessary for the malignant transformation of melanocytes. This shows a complex role of melanogenesis in melanoma development defined by chemical properties of melanin and the nature of generating pathways such as eu- and pheomelanogenesis. While eumelanin is believed to provide radioprotection and photoprotection by acting as an efficient antioxidant and sunscreen, pheomelanin, being less photostable, can generate mutagenic environment after exposure to the short-wavelength UVR. Melanogenesis by itself and its highly reactive intermediates show cytotoxic, genotoxic, and mutagenic activities, and it can stimulate glycolysis and hypoxia-inducible factor 1-alpha (HIF-1α) activation, which, combined with their immunosuppressive effects, can lead to melanoma progression and resistance to immunotherapy. On the other hand, melanogenesis-related proteins can be a target for immunotherapy. Interestingly, clinicopathological analyses on advanced melanomas have shown a negative correlation between tumor pigmentation and diseases outcome as defined by overall survival and disease-free time. This indicates a "Yin and Yang" role for melanin and active melanogenesis in melanoma development, progression, and therapy. Furthermore, based on the clinical, experimental data and diverse effects of melanogenesis, we propose that inhibition of melanogenesis in advanced melanotic melanoma represents a realistic adjuvant strategy to enhance immuno-, radio-, and chemotherapy.

Role of reactive oxygen species in tumors based on the 'seed and soil' theory: A complex interaction (Review)

Tumor microenvironment (TME) can serve as the 'soil' for the growth and survival of tumor cells and function synergically with tumor cells to mediate tumor progression and therapeutic resistance. Reactive oxygen species (ROS) is somewhat of a double‑edged sword for tumors. Accumulating evidence has reported that regulating ROS levels can serve an anti‑tumor role in the TME, including the promotion of cancer cell apoptosis, inhibition of angiogenesis, preventing immune escape, manipulating tumor metabolic reorganization and improving drug resistance. In the present review, the potential role of ROS in anti‑tumor therapy was summarized, including the possibility of directly or indirectly targeting the TME.

Role of necroptosis in infection-related, immune-mediated, and autoimmune skin diseases

Regulated necrosis, also termed necroptosis, is another programmed cell death depending on a unique molecular pathway that does not overlap with apoptosis. Tumor necrosis factor and Toll-like receptor family members, interferon, and other mediators are the factors that mainly cause necroptosis. Activating necroptosis by ligands of death receptors requires the kinase activity of receptor-interacting proteins 1 and 3, and a mixed lineage kinase domain-like protein, which is a critical downstream mediator of necroptosis. Increasing evidence has revealed that necroptosis does not only involve physiological regulation but also the occurrence, development, and prognosis of certain diseases, such as septicemia, neurodegenerative diseases, and ischemic-reperfusion injury. Many excellent documented systematic discussions of necroptosis and its role in various skin diseases. In this review, we summarize the molecular mechanism of necroptosis, as well as the current knowledge on the contribution of necroptosis, in infection-related, immune-mediated, autoimmune skin diseases, and malignant skin tumors.

Pigmentation Levels Affect Melanoma Responses to Coriolus versicolor Extract and Play a Crucial Role in Melanoma-Mononuclear Cell Crosstalk

Melanoma, the malignancy originating from pigment-producing melanocytes, is the most aggressive form of skin cancer and has a poor prognosis once the disease starts to metastasize. The process of melanin synthesis generates an immunosuppressive and mutagenic environment, and can increase melanoma cell resistance to different treatment modalities, including chemo-, radio- or photodynamic therapy. Recently, we have shown that the presence of melanin pigment inhibits the melanoma cell response to bioactive components of Coriolus versicolor (CV) Chinese fungus. Herein, using the same human melanoma cell line in which the level of pigmentation can be controlled by the L-tyrosine concentration in culture medium, we tested the effect of suppression of melanogenesis on the melanoma cell response to CV extract and investigated the cell death pathway induced by fungus extract in sensitized melanoma cells. Our data showed that susceptibility to CV-induced melanoma cell death is significantly increased after cell depigmentation. To the best of our knowledge, we are the first to demonstrate that CV extract can induce RIPK1/RIPK3/MLKL-mediated necroptosis in depigmented melanoma cells. Moreover, using the co-culture system, we showed that inhibition of the tyrosinase activity in melanoma cells modulates cytokine expression in co-cultured mononuclear cells, indicating that depigmentation of melanoma cells may activate immune cells and thereby influence a host anticancer response.

Extract from the Coriolus versicolor Fungus as an Anti-Inflammatory Agent with Cytotoxic Properties against Endothelial Cells and Breast Cancer Cells

Chronic inflammation is a well-recognised tumour-enabling component, which includes bioactive molecules from cells infiltrating the tumour microenvironment and increases the risk of cancer progression. Since long-term use of the currently available anti-inflammatory drugs used in cancer therapy causes numerous side effects, the aim of this study was to investigate the effect of an extract isolated from the Coriolus versicolor fungus (CV extract) on HUVEC endothelial cells and MCF-7 breast cancer cells in a pro-inflammatory microenvironment mimicked by lipopolysaccharide (LPS). The cells were simultaneously stimulated with the LPS and CV extract. After co-treatment, the cell viability, generation of reactive oxygen species (ROS), wound-healing assay, production of the pro-inflammatory and pro-angiogenic factors (interleukin (IL) 6, IL-8, and metalloproteinase (MMP) 9)), as well as expression of Toll-like receptor (TLR) 4 and phosphorylated IκB (p-IκB) were evaluated. The results showed that the CV extract inhibited IL-6, IL-8, and MMP-9 production by the LPS-stimulated cells. This effect was accompanied by a decrease in TLR4 and p-IκB expression. The CV extract also had anti-migratory properties and induced a cytotoxic effect on the cells that was enhanced in the presence of LPS. The observed cytotoxicity was associated with an increase in ROS generation. We conclude that the CV extract possesses cytotoxic activity against cancer cells and endothelial cells and has the ability to inhibit the expression of the pro-tumorigenic factors associated with inflammation.

Tumor Necrosis Factor Receptor-1 (p55) Deficiency Attenuates Tumor Growth and Intratumoral Angiogenesis and Stimulates CD8+ T Cell Function in Melanoma

The role of tumor necrosis factor-α (TNF-α) in shaping the tumor microenvironment is ambiguous. Consistent with its uncertain role in melanoma, TNF-α plays a dual role, either acting as a cytotoxic cytokine or favoring a tumorigenic inflammatory microenvironment. TNF-α signals via two cognate receptors, namely TNFR1 (p55) and TNFR2 (p75), which mediate divergent biological activities. Here, we analyzed the impact of TNFR1 deficiency in tumor progression in the B16.F1 melanoma model. Tumors developed in mice lacking TNFR1 (TNFR1 knock-out; KO) were smaller and displayed lower proliferation compared to their wild type (WT) counterpart. Moreover, TNFR1 KO mice showed reduced tumor angiogenesis. Although no evidence of spontaneous metastases was observed, conditioned media obtained from TNFR1 KO tumors increased tumor cell migration. Whereas the analysis of tumor-associated immune cell infiltrates showed similar frequency of total and M2-polarized tumor-associated macrophages (TAMs), the percentage of CD8⁺ T cells was augmented in TNFR1 KO tumors. Indeed, functional ex vivo assays demonstrated that CD8⁺ T cells obtained from TNFR1KO mice displayed an increased cytotoxic function. Thus, lack of TNFR1 attenuates melanoma growth by modulating tumor cell proliferation, migration, angiogenesis and CD8⁺ T cell accumulation and activation, suggesting that interruption of TNF-TNFR1 signaling may contribute to control tumor burden.

Salinomycin induces autophagic cell death in salinomycin-sensitive melanoma cells through inhibition of autophagic flux

Several literature has shown that salinomycin (Sal) is able to kill various types of cancer cells through different signaling pathways. However, its effect on melanoma has seldom been reported. We examined the anti-cancer efficacy of Sal in melanoma cell lines, and found six of eight cell lines were sensitive to Sal. Given the fact that the roles of Sal are diverse in different cancer types, we were eager to figure out the mechanism involved in the current study. We noticed the most sensitive line, SK-Mel-19, showed a typical morphological change after Sal treatment. The autophagy inhibitor, 3-MA, could effectively suppress Sal-induced cell death. It could also facilitate the increase of autophagic markers and reduce the turnover of autophagosomes, which resulted in an aberrant autophagic flux. On the other hand, Sal could stimulate endoplasmic reticulum stress and cause an accumulation of dysfunctional mitochondria. We also discovered a potential correlation between LC3B mRNA level and its sensitivity to Sal in 43 clinical melanoma samples. Overall, our results indicated that Sal could have multiple effect on melanoma cells and induce autophagic cell death in certain kinds of cells, which provided a new insight into the chemotherapy for melanoma.

Transcriptional characterization of conjunctival melanoma identifies the cellular tumor microenvironment and prognostic gene signatures

This study characterizes the transcriptome and the cellular tumor microenvironment (TME) of conjunctival melanoma (CM) and identifies prognostically relevant biomarkers. 12 formalin-fixed and paraffin-embedded CM were analyzed by MACE RNA sequencing, including six cases each with good or poor clinical outcome, the latter being defined by local recurrence and/or systemic metastases. Eight healthy conjunctival specimens served as controls. The TME of CM, as determined by bioinformatic cell type enrichment analysis, was characterized by the enrichment of melanocytes, pericytes and especially various immune cell types, such as plasmacytoid dendritic cells, natural killer T cells, B cells and mast cells. Differentially expressed genes between CM and control were mainly involved in inhibition of apoptosis, proteolysis and response to growth factors. POU3F3, BIRC5 and 7 were among the top expressed genes associated with inhibition of apoptosis. 20 genes, among them CENPK, INHA, USP33, CASP3, SNORA73B, AAR2, SNRNP48 and GPN1, were identified as prognostically relevant factors reaching high classification accuracy (area under the curve: 1.0). The present study provides new insights into the TME and the transcriptional profile of CM and additionally identifies new prognostic biomarkers. These results add new diagnostic tools and may lead to new options of targeted therapy for CM.

Chloroacridine derivatives as potential anticancer agents which may act as tricarboxylic acid cycle enzyme inhibitors

PURPOSE

This paper concerns the cytotoxicity of 9-chloro-1-nitroacridine (1a) and 9-chloro-4-methyl-1-nitroacridine (1b) against two biologically different melanoma forms: melanotic and amelanotic. Melanomas are tumors characterized by high heterogeneity and poor susceptibility to chemotherapies. Among new analogs synthesized by us, compound 1b exhibited the highest anticancer potency. Because of that, in this study, we analyzed the mechanism of action for 1a and its 4-methylated derivative, 1b, against a pair of biological melanoma forms, with regard to proliferation, cell death mechanism and energetic state.

METHODS

Cytotoxicity was evaluated by XTT assay. Cell death was estimated by plasma membrane structure changes (phosphatidylserine externalization), caspase activation, and ROS presence. The energetic state of cells was estimated based on NAD and ATP levels, and the activity of tricarboxylic acid cycle enzymes (pyruvate dehydrogenase complex, aconitase, isocitrate dehydrogenase).

RESULTS

The chloroacridines affect biological forms of melanoma in different ways. Amelanotic (Ab) melanoma (with inhibited melanogenesis and higher malignancy) was particularly sensitive to the action of the chloroacridines. The Ab melanoma cells died through apoptosis and through death without caspase activation. Diminished activity of TAC enzymes was noticed among Ab melanoma cells together with ATP/NAD depletion, especially in the case of 1b.

CONCLUSION

Our data show that the biological forms of the tumors responded to 1a and its 4-methylated analog in different ways. 1a and 1b could be inducers of regulated melanoma cell death, especially the amelanotic form. Although the mechanism of the cell death is not fully understood, 1b may act by interfering with the TAC enzymes and blocking specific pathways leading to tumor growth. This could encourage further investigation of its anticancer activity, especially against the amelanotic form of melanoma.

Forty-year prognosis after plaque brachytherapy of uveal melanoma

In this study, the long-term patient survival after plaque brachytherapy of uveal melanoma is examined. All patients treated between 1980 and 1999 at a single institution were included (n = 677). 533 (79%) had deceased before the end of follow-up. The median follow-up for the 144 survivors was 25.4 years (SD 5.2). Uveal melanoma-related mortality was 18% by 5 years, 28% by 10 years, 32% by 15 years, 35% by 20 years, and 36% by 25 to 40 years. 172 of 209 (82%) uveal melanoma-related deaths occurred within the first decade after brachytherapy. Relative survival rates were 74% at 5 years, 64% at 10 years, 62% at 20 years, 83% at 30 years and ≥100% at 32 to 40 years. Tumor diameter and local recurrence were independent predictors of uveal melanoma-related mortality in multivariate Cox proportional hazards analysis. In conclusion, uveal melanoma has a high mortality rate and most uveal melanoma-related deaths occur in the first decade after treatment. Long-term survivors may have a survival advantage to individuals of the same sex and age from the general population.

Trametes versicolor (Synn. Coriolus versicolor) Polysaccharides in Cancer Therapy: Targets and Efficacy

Coriolus versicolor (L.) Quél. is a higher fungi or mushroom which is now known by its accepted scientific name as Trametes versicolor (L.) Lloyd (family Polyporaceae). The polysaccharides, primarily two commercial products from China and Japan as PSP and PSK, respectively, have been claimed to serve as adjuvant therapy for cancer. In this paper, research advances in this field, including direct cytotoxicity in cancer cells and immunostimulatory effects, are scrutinised at three levels: in vitro, in vivo and clinical outcomes. The level of activity in the various cancers, key targets (both in cancer and immune cells) and pharmacological efficacies are discussed.