Melanoma Chemoprevention: Current Status and Future Prospects

Swimming upregulates APOL3 through regulating macrophage polarization to inhibit glycolysis and the development of melanoma

This study investigated the role of swimming exercise in regulating melanoma tumour growth and glycolysis in cancer cells, the specific mechanism involved was also studied. In our study, a murine melanoma tumour model was established to assess the impact of swimming on tumour growth. The mRNA and protein expressions were assessed using qRT-PCR, western blot, and IHC. The metabolic behavior of melanoma cells was examined through lactic acid level measurements and glucose consumption assessments. CCK-8 and colony formation assays were used to detect cell viability and proliferation. ELISA was employed to determine the levels of cytokines secreted by macrophages. The interaction between APOL3 and STAT3 was analyzed by dual luciferase reporter gene and ChIP assays. Our results demonstrated that swimming exercise suppressed melanoma growth in mice by suppressing glycolysis, which might be related to APOL3 upregulation. In addition, downregulation of APOL3 in melanoma was associated with poor prognosis, and APOL3 overexpression markedly suppressed melanoma cell proliferation by reducing glucose uptake and lactate production in vitro. Mechanistically, STAT3 directly down-regulated APOL3 transcription. Swimming upregulated APOL3 by inactivating the IL-6R-STAT3 signaling axis in melanoma cells by inhibiting the secretion of IL-6 by M2 macrophages. As expected, IL-6 secreted by M2 macrophages promoted glycolysis in melanoma cells by reducing APOL3 expression. In summary, swimming inactivated the IL-6R/STAT3 signaling axis in melanoma cells by inhibiting the secretion of IL-6 by M2 macrophages, which could suppress the growth of melanoma in the body by upregulating APOL3 to inhibit glycolysis.

Phytoconstituent-derived zingerone nanoparticles disrupt the cell adhesion mechanism and suppress cell motility in melanoma B16F10 cells

Combining phytochemicals and nanotechnology to improve the unfavorable innate properties of phytochemicals and develop them into potent nanomedicines to enhance antitumor efficacy has become a novel strategy for cancer chemoprevention. Melanoma is the most aggressive, metastatic, and deadly disease of the primary cutaneous neoplasms. In this study, we fabricated phytoconstituent-derived zingerone nanoparticles (NPs) and validated their effects on cell adhesion and motility in melanoma B16F10 cells. Our data indicated that zingerone NPs significantly induced cytotoxicity and anti-colony formation and inhibited cell migration and invasion. Moreover, zingerone NPs dramatically interfered with the cytoskeletal reorganization and markedly delayed the period of cell adhesion. Our results also revealed that zingerone NPs-mediated downregulation of MMPs (matrix metalloproteinases) activity is associated with inhibiting cell adhesion and motility. We further evaluated the effects of zingerone NPs on Src/FAK /Paxillin signaling, our data showed that zingerone NPs significantly inhibited the protein activities of Src, FAK, and Paxillin, indicating that they play important roles in zingerone NP-mediated anti-motility and anti-invasion in melanoma cells. Accordingly, the phytoconstituent-zingerone NPs can strengthen the inhibition of tumor growth, invasion, and metastasis in malignant melanoma. Altogether, these multi-pharmacological benefits of zingerone NPs will effectively achieve the purpose of melanoma prevention and invasion inhibition.

Oxidative State in Cutaneous Melanoma Progression: A Question of Balance

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

Identification of genomic-wide genetic links between cutaneous melanoma and obesity-related physical traits via cFDR

BACKGROUND

Both epidemiological and clinical studies have suggested the comorbidity between cutaneous melanoma (CM) and obesity-related physical traits. However, it remains unclear about their shared genetic architecture.

OBJECTIVE

To determine the shared genetic architecture between CM and obesity-related physical traits through conditional false discovery rate (cFDR) analysis.

METHOD

Quantile-quantile plots were firstly built to assess the pleiotropic enrichment of shared single nucleotide polymorphisms between CM and each trait. Then, cFDR and conjunctional cFDR (ccFDR) were used to identify the shared risk loci between CM and each trait. Moreover, the functional evaluation of shared risk genes was carried out through analyses of expression quantitative trait loci (eQTL), Kyoto Encyclopedia of Genes and Genomes and gene ontology, respectively. Finally, single-cell sequence analysis was performed to locate the expression of eQTL-mapped genes in tissues.

RESULTS

Successive pleiotropic enrichment was found between CM and 5 obesity-related traits or height. 24 shared risk loci were identified between CM and 13 traits except appendicular lean mass using ccFDR analysis, with 17 novel and 4 validated loci. The functions of ccFDR-identified and eQTL-mapped genes were revealed to be mainly involved in cellular senescence, proliferation, meiotic nuclear division, cell cycle, and the metabolism of lipid, cholesterol and glucose. Single-cell sequence analysis showed that keratinocytes contribute to the occurrence and aggressiveness of CM through secreting paracrine cytokines.

CONCLUSION

Our findings demonstrate the significant genetic correlation between CM and obesity-related physical traits, which may provide a novel genetical basis for the pathogenesis and treatment of CM.

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.

Trigonelline, a plant derived alkaloid prevents ultraviolet-B-induced oxidative DNA damage in primary human dermal fibroblasts and BALB/c mice via modulation of phosphoinositide 3-kinase-Akt-Nrf2 signalling axis

BACKGROUND

DNA is the main target for UV-B-irradiation-induced skin photodamage and accounts for 90 % of all the non-melanoma skin cancers.

PURPOSE

In this study, we explored the mechanistic basis of photoprotective effect of Trigonelline, a naturally occurring alkaloid from the Trigonella foenum-graecum, against UV-B-induced oxidative DNA Damage Response using Primary Human Dermal Fibroblasts (HDFs) and BALB/C mice as models of skin photodamage.

METHODS

Primary HDFs were subjected to UV-B exposure (10 mJ/cm²) with or without TG for 24 h. Effect of UV-B exposure and TG treatment was evaluated by analyzing the cell survival, cellular morphology, oxidative stress & DNA damage response markers by performing biochemical studies, florescent microscopy & protein expression studies. In in-vivo study, TG pre-treated BALB/c mice were -irradiated with 180 mJ/cm² of UV-B dose thrice a week on alternative days for four months, followed by topical application of different concentrations of TG. The photodamage caused by UV-B exposure and its ameleoriation by topical treatment of TG was studied by physical and morphological appearance and analyzing the oxidative stress & DNA damage response markers from skin.

RESULTS

We found that TG significantly alleviates UV-B-induced cell death effects in HDFs. TG protects HDF cells and BALB/c mice from UV-B-induced DNA damage by regulating the expression profile of key protein markers of DNA damage which include P53, ATM, ATR, ϒH₂AX, Chk1 and Chk2. We found that TG offers geno-protection to UV-B-irradiated HDFs by alleviating CPD induction, reducing the number of TUNEL positive cells and by decreasing the expression levels of DNA damage marker protein ϒH₂AX in immunocytochemistry. Further, we found that TG prevents the UVB induced oxidative stress by activating the PI3K-AKT-Nrf2 signalling pathway. On employing PI3K inhibitor, LY294002, we found the expression of ϒH₂AX and p-P53 is significantly increased compared to UV-B treated only, indicating that TG mediates the geno-protection against UV-B irradiation via PI3K-AKT-Nrf2 signalling pathway.

CONCLUSION

Current study presents for the first time the photo-protective role of TG against UV-B-induced oxidative DNA damage and provides its mechanistic insights also and provide strong evidence for TG to be carried forward as a potential remedial and cosmeceutical agent against UV-B-induced skin photodamage disorders.

Antitumor/anti-angiogenesis efficacy of epigallocatechin gallate nanoformulated with antioxidant in melanoma

Aim: Epigallocatechin gallate (EGCG) derived from green tea has poor stability; therefore, to enhance its bioavailability and anticancer efficiency, we synthesized three different nanoformulations. We hypothesized that these three nanoformulations of EGCG (nano-EGCG) would enhance EGCG’s stability and improve its anticancer and antiangiogenic activity against melanoma compared with free EGCG. Methods: We prepared nano-EGCG using a copolymerization method with the UV blocker ZnO and the antioxidants lycopene and olive oil. Results: The different nano-EGCG formulation exhibited improved EGCG stability and greater suppression of melanoma growth than free EGCG. Nanoformulation preparation methods efficiently prevented the loss of EGCG activity and are a favorable approach for the treatment of melanoma. Conclusion: Nano-EGCG formulations had enhanced stability and produced greater suppression of melanoma tumor growth and angiogenesis compared with free EGCG.

Flower Extracts from Ornamental Plants as Sources of Sunscreen Ingredients: Determination by In Vitro Methods of Photoprotective Efficacy, Antigenotoxicity and Safety

Plants are sources of sunscreen ingredients that prevent cellular mutations involved in skin cancer and aging. This study investigated the sunscreen properties of the extracts from some ornamental plants growing in Colombia. The UV filter capability of the flower extracts obtained from Rosa centifolia L., Posoqueria latifolia (Rudge) Schult, and Ipomoea horsfalliae Hook. was examined. Photoprotection efficacies were evaluated using in vitro indices such as sun protection factor and critical wavelength. UVB antigenotoxicity estimates measured with the SOS Chromotest were also obtained. Extract cytotoxicity and genotoxicity were studied in human fibroblasts using the trypan blue exclusion and Comet assays, respectively. Major compounds of the promising flower extracts were identified by UHPLC-ESI+-Orbitrap-MS. The studied extracts showed high photoprotection efficacy and antigenotoxicity against UVB radiation, but only the P. latifolia extract showed broad-spectrum photoprotection at non-cytotoxic concentrations. The P. latifolia extract appeared to be safer for human fibroblast cells and the R. centifolia extract was shown to be moderately cytotoxic and genotoxic at the highest assayed concentrations. The I. horsfalliae extract was unequivocally cytotoxic and genotoxic. The major constituents of the promising extracts were as follows: chlorogenic acid, ecdysterone 20E, rhamnetin-rutinoside, cis-resveratrol-diglucoside, trans-resveratrol-diglucoside in P. latifolia; quercetin, quercetin-glucoside, quercetin-3-rhamnoside, kaempferol, kaempferol-3-glucoside, and kaempferol-rhamnoside in R. centifolia. The potential of the ornamental plants as sources of sunscreen ingredients was discussed.

CD96 as a Potential Diagnostic Biomarker and New Target for Skin Cutaneous Melanoma

Skin cutaneous melanoma has high morbidity and mortality. Identification of reliable and quantitative melanoma biomarkers could facilitate an early diagnosis and improve survival and morbidity rates. CD96 has a significant role in adjusting immune function. Although the abnormal expression of CD96 has been reported to participate in carcinogenesis in many human types of cancer, the bioinformatics role of the CD96 in melanoma is unknown. Expression degrees and their underlying functions were first studied by this study. According to TCGA, GTEx, and gene expression profile interaction analysis dataset in this paper, compared with normal skin tissues, CD96 was expressed at higher levels in human cutaneous melanoma skin tissues. Meanwhile, we detected the relative CD96 expression levels by immunohistochemistry. Gene functional enrichment analyses were applied through cBioPortal database analysis. CD96 was clearly upregulated in skin cutaneous melanoma patients and carried out its effects through regulating several signaling pathways, containing the JAK-STAT, PI3K-Akt, and MAPK. Taken together, the analysis results indicated that CD96 could be used as a new clinical bioindicator as well as an underlying medicinal target for cutaneous melanoma.

Luteolin binds Src, promotes STAT3 protein ubiquitination and exerts anti-melanoma effects in cell and mouse models

Signal transducer and activator of transcription 3 (STAT3) has been proposed as a target for melanoma prevention. Luteolin, a bioactive flavonoid abundant inmedicinal herbs, has been reported to have anti-melanoma activity in vitro. However, its in vivo anti-melanoma effects and underlying mechanisms have not been fully elucidated. In this study, ten cell lines and two mouse models (B16F10 allograft and A375 xenograft models) were used for assessing the in vitro and in vivo anti-melanoma effects of luteolin. A STAT3 over-activated stable A375 cell line was used to determine the contribution of STAT3 signaling in luteolin's anti-melanoma effects. Results showed that luteolin dose-dependently reduced viability of melanoma cells. Luteolin also induced apoptosis in, and suppressed migration and invasion of, A375 and B16F10 melanoma cells. Mechanistically, luteolin inhibited phosphorylation of STAT3 and Src (an upstream kinase of STAT3), accelerated ubiquitin-proteasome pathway-mediated STAT3 degradation, and downregulated the expression of STAT3-targeted genes involved in cell survival and invasion in melanoma cells. Molecular modelling and surface plasmon resonance imaging showed that luteolin stably bound to the protein kinase domain of Src. Animal studies demonstrated that prophylactic administration of luteolin restrained melanoma growth and Src/STAT3 signaling in both A375 and B16F10 melanoma-bearing mice. Moreover, luteolin's anti-melanoma effects were diminished by STAT3 over-activation in A375 cells. Our findings indicate that luteolin inhibits STAT3 signaling by suppressing STAT3 activation and promoting STAT3 protein degradation in melanoma cells, thereby exhibiting anti-melanoma effects. This study provides further pharmacological groundwork for developing luteolin as a chemopreventive agent against melanoma.

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.

Skin cancer, including related pathways and therapy and the role of luteolin derivatives as potential therapeutics

Cutaneous malignant melanoma is the fastest growing and the most aggressive form of skin cancer that is diagnosed. However, its incidence is relatively scarce compared to the highest mortality rate of all skin cancers. The much more common skin cancers include nonmelanoma malignant skin cancers. Moreover, over the past several decades, the frequency of all skin cancers has increased much more dynamically than that of almost any other type of cancer. Among the available therapeutic options for skin cancers, chemotherapy used immediately after the surgical intervention has been an essential element. Unfortunately, the main problem with conventional chemopreventive regimens involves the lack of response to treatment and the associated side effects. Hence, there is a need for much more effective anticancer drugs. Correspondingly, the targeted alternatives have involved phytochemicals, which are safer chemotherapeutic agents and exhibit competitive anticancer activity with high therapeutic efficacy. Among polyphenolic compounds, some flavonoids and their derivatives, which are mostly found in medicinal plants, have been demonstrated to influence the modulation of signaling pathways at each stage of the carcinogenesis process, which is also important in the context of skin cancers. Hence, this review focuses on an exhaustive overview of the therapeutic effects of luteolin and its derivatives in the treatment and prevention of skin cancers. The bioavailability and structure–activity relationships of luteolin derivatives are also discussed. This review is the first such complete account of all of the scientific reports concerning this particular group of natural compounds that target a specific area of neoplastic diseases.

Etiologies of Melanoma Development and Prevention Measures: A Review of the Current Evidence

Simple Summary

Melanoma constitutes a major public health risk, with the rates of diagnosis increasing on a yearly basis. Monitoring for risk factors and preventing dangerous behaviors that increase melanoma risk, such as tanning, are important measures for melanoma prevention. Additionally, assessing the effectiveness of various methods to prevent sun exposure and sunburns—which can lead to melanoma—is important to help identify ways to reduce the development of melanoma. We summarize the recent evidence regarding the heritable and behavioral risks underlying melanoma, as well as the current methods used to reduce the risk of developing melanoma and to improve the diagnosis of this disease.

Abstract

(1) Melanoma is the most aggressive dermatologic malignancy, with an estimated 106,110 new cases to be diagnosed in 2021. The annual incidence rates continue to climb, which underscores the critical importance of improving the methods to prevent this disease. The interventions to assist with melanoma prevention vary and typically include measures such as UV avoidance and the use of protective clothing, sunscreen, and other chemopreventive agents. However, the evidence is mixed surrounding the use of these and other interventions. This review discusses the heritable etiologies underlying melanoma development before delving into the data surrounding the preventive methods highlighted above. (2) A comprehensive literature review was performed to identify the clinical trials, observational studies, and meta-analyses pertinent to melanoma prevention and incidence. Online resources were queried to identify epidemiologic and clinical trial information. (3) Evidence exists to support population-wide screening programs, the proper use of sunscreen, and community-targeted measures in the prevention of melanoma. Clinical evidence for the majority of the proposed preventive chemotherapeutics is presently minimal but continues to evolve. (4) Further study of these chemotherapeutics, as well as improvement of techniques in artificial intelligence and imaging techniques for melanoma screening, is warranted for continued improvement of melanoma prevention.

Plants growing in Colombia as sources of active ingredients for sunscreens

INTRODUCTION

Plants can be sources of photoprotective/antigenotoxic compounds that prevent cellular mutations involved in skin cancer and aging by regulating UV-induced mutability.

PURPOSE

The study was aimed at investigating the sunscreen properties of plants growing in Colombia.

MATERIALS AND METHODS

Ultraviolet (UV) radiation-absorption capability of different plant extracts was examined. In vitro photoprotection efficacies were evaluated using in vitro indices such as sun protection factor (SPF_in vitro) and critical wavelength (λc). Pearson correlation analysis was used to examine the relationship between SPF_in vitro and complementary UVB- antigenotoxicity estimates (%GI) based on the SOS Chromotest database. The cytotoxicity in human fibroblasts was studied using the trypan blue exclusion assay. Major compounds of promising plant extracts were determined by gas chromatography coupled to mass spectrometry (GC/MS).

RESULTS

We showed that plant extracts have sunscreen properties against UVB, whereas broad-spectrum radiation protection efficacy was poor. SPF_in vitro and %GI were correlated (R = 0.71, p < .0001) for the plant extracts under study. Three extracts obtained from Achyrocline satureioides, Chromolaena pellia, and Lippia origanoides species resulted to possess high protection efficacy and relatively low cytotoxicity in human fibroblasts. These plant extracts contained major compounds such as α-pinene, trans-β-caryophyllene, γ-muurolene, γ-cadinene and caryophyllene oxide in A. Satureioides extract, trans-β-caryophyllene, caryophyllene oxide, squalene and α-amyrin in C. pellia extract, and p-cymene, carvacrol, trans-β-caryophyllene and pinocembrin in L. origanoides extract.

CONCLUSIONS

Plants growing in Colombia contain compounds that can be useful for potential sunscreens. SPF_in vitro and %GI estimates were correlated, but %GI estimates were more sensitive to detecting activity at lower plant extract concentrations. Our results supported the need to use DNA damage detection assays as a complement to photoprotection efficacy measurement.

Rosa platyacantha Schrenk from Kazakhstan-Natural Source of Bioactive Compounds with Cosmetic Significance

Plants belonging to the Rosa genus are known for their high content of bioactive molecules and broad spectrum of healing and cosmetic activities. Rosa platyacantha Schrenk is a wild-type species abundant in the mountainous regions of Kazakhstan. The phytochemical composition as well as the bioactivity of R. platyacantha extracts have not been fully investigated to date. In this study, various parts of R. platyacantha plant, collected in Almaty region, Kazakhstan, were used to prepare five hydroalcoholic extracts (R1–R5). The extracts were compared for the content of phytochemicals and selected biological activities, which are important for the potential cosmetic application of R. platyacantha. Extract R3, prepared from flower buds, showed the most significant antioxidant and tyrosinase inhibitory potential, decreasing the monophenolase and diphenolase activities of tyrosinase. Extract R3 showed also collagenase inhibitory activity and cytotoxicity against human melanoma cells A375, being less cytotoxic for noncancerous skin keratinocytes HaCaT. Analysis of fractions E and F, obtained from R3 extracts, revealed that quercetin, kaempferol, rutin, and their derivatives are more likely responsible for the tyrosinase inhibitory properties of R. platyacantha extracts.

Targeting nutrient metabolism with FDA-approved drugs for cancer chemoprevention: Drugs and mechanisms

Proliferating cancer cells exhibit metabolic alterations and specific nutritional needs for adapting to their rapid growth. These changes include using aerobic glycolysis, lipid metabolic disorder, and irregular protein degradation. It may be useful to target metabolic abnormalities for cancer chemoprevention. Epidemiological and mechanism-related studies have indicated that many FDA-approved anti-metabolic drugs decrease tumor risk, inhibit tumor growth, or enhance the effect of chemotherapeutic drugs. Drugs targeting nutrient metabolism have fewer side effects with long-term use compared to chemotherapeutic drugs. The characteristics of these drugs make them promising candidates for cancer chemoprevention. Here, we summarize recent discoveries of the chemo-preventive effects of drugs targeting nutrient metabolic pathways and discuss future applications and challenges. Understanding the effects and mechanisms of anti-metabolic drugs in cancer has important implications for exploring strategies for cancer chemoprevention.

Phenolic compounds of blueberries (Vaccinium spp) as a protective strategy against skin cell damage induced by ROS: A review of antioxidant potential and antiproliferative capacity

The skin is a tissue with a high metabolic activity that acts as a protective layer for the internal organs of the body. This tissue is exposed to a variety of damaging agents, including reactive oxygen species (ROS), which can lead to oxidative damage to various macromolecules, disrupting vital cellular processes and increasing mutations. A situation referred to as oxidative stress occurs when a large amount of oxidants exceeds the capacity of the antioxidant defense system. Oxidative stress is considered a contributory factor to the aging process and the pathogenesis of various skin diseases, including cancer. Several current studies seek to identify new natural compounds with properties that mitigate the harmful effects of ROS, thereby acting as blockers or suppressors of the carcinogenesis process. This review briefly presents the relationship between ultraviolet radiation, ROS, and skin damage; and summarizes the in vitro and in vivo experimental evidence of the chemopreventive effect on skin cancer of phenolic compounds from blueberries (Vaccinium spp). Although several studies addressed the topic of bioactive compounds and their activities as possible anticancer agents, none have focused on the antioxidative action and antiproliferative effects on skin cancer of phenolic compounds derived from blueberries.

Viability and Antioxidant Effects of Traditional Cooling Rice Powder (bedak sejuk) Made from Oryza sativa ssp. Indica and Oryza sativa ssp. japonica on UVB-Induced B164A5 Melanoma Cells

BACKGROUND

Traditional cooling rice powder (bedak sejuk) is a fermented rice-based cosmetic that is applied topically on one's skin, as an overnight facial mask. According to user testimonies, bedak sejuk beautifies and whitens skin, whereby these benefits could be utilised as a potential melanoma chemopreventive agent.

OBJECTIVE

Hence, this study aimed to determine the effects of bedak sejuk made from Oryza sativa ssp. indica (Indica) and Oryza sativa ssp. japonica (Japonica) on UVB-induced B164A5 melanoma cells, and also identify the antioxidant capacities of both types of bedak sejuk.

METHODS

The optimum dose of Indica and Japonica bedak sejuk to treat the cells was determined via the MTT assay. Then, the antioxidant capacities of both types of bedak sejuk were determined using the FRAP assay.

RESULTS

From the MTT assay, it was found that Indica and Japonica bedak sejuk showed no cytotoxic effects towards the cells. Hence, no IC50 can be obtained and two of the higher doses, 50 and 100 g/L were chosen for treatment. In the FRAP assay, Indica bedak sejuk at 50 and 100 g/L showed FRAP values of 0.003 ± 0.001 μg AA (ascorbic acid)/g of bedak sejuk and 0.004 ± 0.0003 μg AA/g of bedak sejuk. Whereas Japonica bedak sejuk at 50 g/L had the same FRAP value as Indica bedak sejuk at 100 g/L. As for Japonica bedak sejuk at 100 g/L, it showed the highest antioxidant capacity with the FRAP value of 0.01 ± 0.0007 μg AA/g of bedak sejuk which was statistically significant (p < 0.05) when compared to other tested concentrations.

CONCLUSION

In conclusion, Japonica bedak sejuk has a higher antioxidant capacity compared to Indica bedak sejuk despite both being not cytotoxic towards the cells. Regardless, further investigations need to be done before bedak sejuk could be developed as potential melanoma chemoprevention agents.

CRISPR/Cas9-mediated Knockout of SIRT6 Imparts Remarkable Antiproliferative Response in Human Melanoma Cells in vitro and in vivo

Melanoma is one of the most aggressive, potentially fatal forms of skin cancer and has been shown to be associated with solar ultraviolet radiation-dependent initiation and progression. Despite remarkable recent advances with targeted and immune therapeutics, lasting and recurrence-free survival remain significant concerns. Therefore, additional novel mechanism-based approaches are needed for effective melanoma management. The sirtuin SIRT6 appears to have a pro-proliferative function in melanocytic cells. In this study, we determined the effects of genetic manipulation of SIRT6 in human melanoma cells, in vitro and in vivo. Our data demonstrated that CRISPR/Cas9-mediated knockout (KO) of SIRT6 in A375 melanoma cells resulted in a significant (1) decrease in growth, viability and clonogenic survival and (2) induction of G1-phase cell cycle arrest. Further, employing a RT² Profiler PCR array containing 84 key transformation and tumorigenesis genes, we found that SIRT6 KO resulted in modulation of genes involved in angiogenesis, apoptosis, cellular senescence, epithelial-to-mesenchymal transition, hypoxia signaling and telomere maintenance. Finally, we found significantly decreased tumorigenicity of SIRT6 KO A375 cells in athymic nude mice. Our data provide strong evidence that SIRT6 promotes melanoma cell survival, both in vitro and in vivo, and could be exploited as a target for melanoma management.

Non-Cytotoxic Sulfated Heterorhamnan from Gayralia brasiliensis Green Seaweed Reduces Driver Features of Melanoma Metastatic Progression

Melanoma is a form of skin cancer with high mortality owing to its fast progression and metastatic capacity. The treatments available nowadays are only palliative in advanced stages of the disease. Thus, alternative therapies for cancer treatment are in demand, and molecules from natural sources, such as polysaccharides, could represent new possible therapeutic approaches. Polysaccharides of freshwater and marine algae with biological activities, such as antitumor properties, are greatly reported in the scientific literature. In the present study, a sulfated heterorhamnan obtained from the green seaweed Gayralia brasiliensis (Gb1 fraction) was chemically characterized and its biological activities in the B16-F10 murine melanoma cell line were evaluated. The Gb1 polysaccharidic fraction tested concentrations presented low or absence of cytotoxicity to B16-F10 cells and neither cell proliferation nor cell cycle were altered. Interestingly, Gb1 treatment decreased B16-F10 cells migration and invasion capabilities and CD44 labeling, showing to be a promising compound for further in vitro and in vivo antitumor studies.

Characterization of Cistus × incanus L. and Cistus ladanifer L. Extracts as Potential Multifunctional Antioxidant Ingredients for Skin Protecting Cosmetics

Skin is constantly exposed to harmful environmental factors, causing photo-oxidative stress in cells and leading to the development of health and aesthetic problems. Multifunctional ingredients of everyday skincare products, possessing antioxidant, UV-protecting, anti-hyperpigmentation, and skin cancer-preventing properties are in high demand. Due to the high content of polyphenolic compounds Cistus × incanus L. and Cistus ladanifer L. are potentially interesting sources of cosmetic ingredients with multiple skin protecting functions. In this study eight extracts from dried C. incanus and C. ladanifer-aerial parts were prepared using 60% (v/v) or 100% (v/v) methanol, on a magnetic stirrer or in Soxhlet apparatus, and compared for their content of phytochemicals and properties important for the skin protection. Extracts from C. incanus prepared in 60% (v/v) methanol contained the highest amount of polyphenolic compounds (331.82-347.27 mg GAE/g DW) and showed the most significant antioxidant activity (IC₅₀ = 3.81-4.05 µg/mL). C. incanus extracts were also effective tyrosinase inhibitors (30-70% inhibition at 100 µg/mL). Statistical correlation analysis revealed that epicatechin, epigallocatechin gallate (EGCG), and myricitrin may be responsible for the antioxidant and tyrosinase inhibitory potential of C. incanus extracts. All analyzed extracts were cytotoxic for human melanoma cells A375 (IC₅₀ = 57.80-199.01 µg/mL), with C. incanus extract prepared in 100% (v/v) methanol using Soxhlet extraction being the most effective. The extracts did not significantly impair the growth of noncancerous human keratinocytes HaCaT. C. incanus and C. ladanifer extracts possess also natural sun protecting activity (SPF 3.42-3.77 at 100 µg/mL), enhancing their anti-hyperpigmentation and anti-melanoma potential.

Chemoprevention agents for melanoma: A path forward into phase 3 clinical trials

Recent progress in the treatment of advanced melanoma has led to unprecedented improvements in overall survival and, as these new melanoma treatments have been developed and deployed in the clinic, much has been learned about the natural history of the disease. Now is the time to apply that knowledge toward the design and clinical evaluation of new chemoprevention agents. Melanoma chemoprevention has the potential to reduce dramatically both the morbidity and the high costs associated with treating patients who have metastatic disease. In this work, scientific and clinical melanoma experts from the national Melanoma Prevention Working Group, composed of National Cancer Trials Network investigators, discuss research aimed at discovering and developing (or repurposing) drugs and natural products for the prevention of melanoma and propose an updated pipeline for translating the most promising agents into the clinic. The mechanism of action, preclinical data, epidemiological evidence, and results from available clinical trials are discussed for each class of compounds. Selected keratinocyte carcinoma chemoprevention studies also are considered, and a rationale for their inclusion is presented. These data are summarized in a table that lists the type and level of evidence available for each class of agents. Also included in the discussion is an assessment of additional research necessary and the likelihood that a given compound may be a suitable candidate for a phase 3 clinical trial within the next 5 years.

Chemoprotective Effects of Dietary Grape Powder on UVB Radiation-Mediated Skin Carcinogenesis in SKH-1 Hairless Mice

Skin cancer is the most frequently diagnosed cancer in the United States, and solar UVR is an established causative factor for approximately 90% of these cases. Despite efforts aimed at UV protection, including use of sunscreen and clothing, annual cases of skin cancer continue to rise. Here, we report that dietary grape powder mitigates UVB-mediated skin carcinogenesis in an SKH-1 hairless mouse model. Using a UVB initiation-promotion protocol, whereby mice were exposed to 180 mJ/cm² UVB two times per week for 28 weeks, we determined the effects of a grape powder-fortified diet (3% or 5%) on skin carcinogenesis. Grape powder consumption at both doses resulted in marked inhibition in tumor incidence, as well as a delay in onset of tumorigenesis. Molecular analyses of skin and tumor tissue showed that grape powder-mediated protective response against UVB-induced skin cancer was accompanied by enhanced DNA damage repair, reduced proliferation, increased apoptosis, and modulations in several oxidative stress markers specifically related to inhibition of oxidative stress and increased reactive oxygen species metabolism. NRF2, an activator of cellular antioxidant response, was decreased by grape powder feeding, suggesting a supportive role in tumor cell survival. Overall, our study suggested that dietary grape, containing several antioxidants in natural amalgamation, may protect against UVB-mediated skin carcinogenesis.

Effects and Mechanism of Nicotinamide Against UVA- and/or UVB-mediated DNA Damages in Normal Melanocytes

Melanoma incidences are increasing rapidly, and ultraviolet (UV) radiation from the sun is believed to be its major contributing factor. UV exposure causes DNA damage in skin which may initiate cutaneous skin cancers including melanoma. Melanoma arises from melanocytes, the melanin-producing skin cells, following genetic dysregulations resulting into hyperproliferative phenotype and neoplastic transformation. Both UVA and UVB exposures to the skin are believed to trigger melanocytic hyperplasia and melanomagenesis. Melanocytes by themselves are deficient in repair of oxidative DNA damage and UV-induced photoproducts. Nicotinamide, an active form of vitamin B3 and a critical component of the human body's defense system has been shown to prevent certain cancers including nonmelanoma skin cancers. However, the mechanism of nicotinamide's protective effects is not well understood. Here, we investigated potential protective effects and mechanism of nicotinamide against UVA- and/or UVB- induced damage in normal human epidermal melanocytes. Our data demonstrated an appreciable protective effect of nicotinamide against UVA- and/or UVB- induced DNA damage in melanocytes by decreasing both cyclobutane pyrimidine dimers and 8-hydroxy-2'-deoxyguanosine levels. We found that the photoprotective response of nicotinamide was associated with the activation of nucleotide excision repair genes and NRF2 signaling. Further studies are needed to validate our findings in in vivo models.

Retrospective study of patients with cutaneous melanoma treated at the Federal University of São Paulo

OBJECTIVE

to evaluate the characteristics of the patients with cutaneous melanoma treated at the São Paulo Hospital - UNIFESP.

METHODS

we conducted a retrospective study of 184 cases of cutaneous melanoma. We analyzed information on gender, age, tumor characteristics, histological characteristics and staging.

RESULTS

mean age at diagnosis was 58.7 years, with homogeneous age distribution between genders and predominance in white individuals (70.6%). There was a predominance of trunk involvement in men (36.7%) and lower limbs in women (42%). Sun exposure, with sunburns, was more common among males (31.2%) than among females (23.5%). There was an approximately three-fold increase in lymph node involvement when the mitotic index rose from zero (11.9%) to one or more mitosis per field (36.2%). In addition, the greater the Breslow thickness, the greater the lymph node involvement and poor the outcomes: 10.2% when less than 1mm and 59.2% when greater than 4mm.

CONCLUSION

the characteristics of patients with cutaneous melanoma treated at Hospital São Paulo are similar to those found in the literature.

Prostate cancer chemoprevention by natural agents: Clinical evidence and potential implications

Prostate cancer (PCa) is the most common non-skin cancer and the second leading cause of cancer-related deaths in American men. Due to its long latency period, PCa is considered as an ideal cancer type for chemopreventive interventions. Chemopreventive agents include various natural or synthetic agents that prevent or delay cancer development, progression and/or recurrence. Pre-clinical studies suggest that many natural products and dietary agents have chemopreventive properties. However, a limited number of these agents have been tested in clinical trials, with varying success. In this review, we have discussed the available clinical studies regarding the efficacy of natural chemopreventive agents against PCa, including tea polyphenols, selenium, soy proteins, vitamins and resveratrol. We have also provided a discussion on the clinical challenges and opportunities for the potential use of chemopreventive agents against PCa. Based on available literature, it appears that the variable outcomes of the chemopreventive clinical studies necessitate a need for additional studies with more rigorous designs and methodical interpretations in order to measure the potential of the natural agents against PCa.

SNHG5 promotes proliferation and induces apoptosis in melanoma by sponging miR-155

Background: Melanoma is the most common malignancy of skin cancer. Small nucleolar RNA host gene 5 (SNHG5), a long non-coding RNA (lncRNA), has been demonstrated to be abnormally expressed in multiple malignances. However, the roles and molecular mechanisms of SNHG5 in melanoma progression have not been well identified. Methods: RT-qPCR assays were used to detect the expression patterns of SNHG5 and microRNA-155 (miR-155). Cell proliferation was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and colony formation assays. Cell apoptosis rate was measured by flow cytometry via double-staining of fluorescein isothiocyanate (FITC)-labeled annexin V (Annexin V-FITC) and propidium iodide (PI). The interaction between SNHG5 and miR-155 was validated using bioinformatics analysis, subcellular fraction assay, luciferase assay and RNA immunoprecipitation (RIP) assay. A mouse model of melanoma was established to further verify the effect of SNHG5 on tumor growth in vivo. Results: SNHG5 expression was upregulated in melanoma tumor tissues and cell lines. Moreover, higher SNHG5 expression was associated with advanced pathogenic status and poor prognosis. Functional analysis showed that SNHG5 knockdown suppressed proliferation and facilitated apoptosis in melanoma cells. Mechanical exploration revealed that SNHG5 acted as a molecular sponge of miR-155 in melanoma cells. Restoration experiments delineated that miR-155 down-regulation partly abrogated SNHG5-knockdown-mediated anti-proliferation and pro-apoptosis effect in melanoma cells. In vivo assays further demonstrated that SNHG5 depletion hindered tumor growth through up-regulating miR-155 expression. Conclusion: SNHG5 promoted the development of melanoma by sponging miR-155 in vitro and in vivo, implying the important implication of lncRNAs in melanoma progression and providing a potential therapeutic target for melanoma.

Melanoma is the most common malignancy of skin cancer. Small nucleolar RNA host gene 5 (SNHG5), a long non-coding RNA (lncRNA), has been demonstrated to be upregulated in tumor tissues and cells of melanoma.

Mechanisms and prevention of UV-induced melanoma

Melanoma is the deadliest form of skin cancer and its incidence is rising, creating a costly and significant clinical problem. Exposure to ultraviolet (UV) radiation, namely UVA (315-400 nm) and UVB (280-315 nm), is a major risk factor for melanoma development. Cumulative UV radiation exposure from sunlight or tanning beds contributes to UV-induced DNA damage, oxidative stress, and inflammation in the skin. A number of factors, including hair color, skin type, genetic background, location, and history of tanning, determine the skin's response to UV radiation. In melanocytes, dysregulation of this UV radiation response can lead to melanoma. Given the complex origins of melanoma, it is difficult to develop curative therapies and universally effective preventative strategies. Here, we describe and discuss the mechanisms of UV-induced skin damage responsible for inducing melanomagenesis, and explore options for therapeutic and preventative interventions.