UV Radiation-induced Damage Research Articles

Small Peptide Derived from SFRP5 Suppresses Melanogenesis by Inhibiting Wnt Activity.

Melanocytes, located in the epidermis' basal layer, are responsible for melanin pigment production, crucial for skin coloration and protection against UV radiation-induced damage. Melanin synthesis is intricately regulated by various factors, including the Wnt signaling pathway, particularly mediated by the microphthalmia-associated transcription factor (MITF). While MITF is recognized as a key regulator of pigmentation, its regulation by the Wnt pathway remains poorly understood. This study investigates the role of Sfrp5pepD, a peptide antagonist of the Wnt signaling pathway, in modulating melanogenesis and its potential therapeutic implications for pigmentary disorders. To tackle this issue, we investigated smaller peptides frequently utilized in cosmetics or pharmaceuticals. Nevertheless, there is a significant scarcity of reports on peptides associated with melanin-related signal modulation or inhibiting melanin production. Results indicate that Sfrp5pepD effectively inhibits Wnt signaling by disrupting the interaction between Axin-1 and β-catenin, thus impeding downstream melanogenic processes. Additionally, Sfrp5pepD suppresses the interaction between MITF and β-catenin, inhibiting their nuclear translocation and downregulating melanogenic enzyme expression, ultimately reducing melanin production. These inhibitory effects are validated in cell culture models suggesting potential clinical applications for hyperpigmentation disorders. Overall, this study elucidates the intricate interplay between Wnt signaling and melanogenesis, highlighting Sfrp5pepD as a promising therapeutic agent for pigmentary disorders. Sfrp5pepD, with a molecular weight of less than 500 Da, is anticipated to penetrate the skin unlike SFRPs. This suggests a strong potential for their use as cosmetics or transdermal absorption agents. Additional investigation into its mechanisms and clinical significance is necessary to enhance its effectiveness in addressing melanin-related skin conditions.

UNDERSTANDING THE IMPACT OF UV RADIATION ON SKIN HEALTH: MECHANISMS, RISKS, AND PHOTOPROTECTION STRATEGIES

This comprehensive review examines the intricate relationship between UV radiation and skin health, delving into its mechanisms, associated risks, and potential photoprotection strategies. Drawing from centuries of herbal medicine and cosmetic practices, the efficacy of antioxidant-rich herbs in shielding against UV radiation-induced damage is highlighted. Studies showcasing the protective properties of plant extracts, such as green and black tea polyphenols and aloe vera formulations, underscore the potential of botanicals in skincare. The rise of herbal sunscreens in response to growing concerns over UV exposure reflects a paradigm shift in skincare practices. The review elucidates the diverse effects of UV radiation on the skin, encompassing sunburns, premature aging, and skin cancer development. Mechanisms underlying UVB-induced skin damage, including collagen breakdown, generation of free radicals, and interference with DNA repair mechanisms, underscore the imperative of implementing protective measures. The role of antioxidants in mitigating UV-induced damage and the development of innovative sunscreen formulations underscores ongoing efforts to enhance photoprotection strategies. Furthermore, the review underscores the multifaceted nature of UV radiation’s impact on skin health, emphasizing the importance of holistic approaches to photoprotection.Future research endeavors aimed at exploring novel photoprotective agents and assessing their efficacy in preserving skin health will be instrumental in mitigating the adverse effects of UV radiation and fostering overall skin well-being.

Hesperidin from Orange Peel as a Promising Skincare Bioactive: An Overview.

The pursuit for better skin health, driven by collective and individual perceptions, has led to the demand for sustainable skincare products. Environmental factors and lifestyle choices can accelerate skin aging, causing issues like inflammation, wrinkles, elasticity loss, hyperpigmentation, and dryness. The skincare industry is innovating to meet consumers' requests for cleaner and natural options. Simultaneously, environmental issues concerning waste generation have been leading to sustainable strategies based on the circular economy. A noteworthy solution consists of citrus by-product valorization, as such by-products can be used as a source of bioactive molecules. Citrus processing, particularly, generates substantial waste amounts (around 50% of the whole fruit), causing unprecedented environmental burdens. Hesperidin, a flavonoid abundant in orange peels, is considered to hold immense potential for clean skin health product applications due to its antioxidant, anti-inflammatory, and anticarcinogenic properties. This review explores hesperidin extraction and purification methodologies as well as key skincare application areas: (i) antiaging and skin barrier enhancement, (ii) UV radiation-induced damage, (iii) hyperpigmentation and depigmentation conditions, (iv) wound healing, and (v) skin cancer and other cutaneous diseases. This work's novelty lies in the comprehensive coverage of hesperidin's promising skincare applications while also demonstrating its potential as a sustainable ingredient from a circular economy approach.

A Review on Formulation and Evaluation of Sunscreen by Using Natural Sources

Sunscreen is a chemical compound that helps shield the skin from ultraviolet light. Sunburn is caused by UVB radiation, but UVA radiation may cause more skin damage. A sunscreen that blocks both wavebands is ideal. The aim of this study was to use medicinal herbs and specific fixed oils to create a topical herbal sunscreen composition. The goal of this project is to create and evaluate a cosmetic (herbal sunscreen) that shields skin from the sun. Natural ingredients with a range of uses, such as emollient, moisturiser, base, anti-acne, and anti-sweating, include hibiscus and aloevera .Rose water, almond oil, vitamin E capsules, hibiscus flowers, etc. Actinic keratosis, squamous cell carcinoma, and melanoma can all be avoided with regular sunscreen use. Chemicals, either organic or inorganic, may be present in sunscreen. Sunscreen cream is another term for sunscreen. The object either absorbs or reflects solar radiation. UV radiation and provides skin defence. The use of screening materials that have been successful in lowering the indication has increased as a result of the rising incidence of skin cancers and the effects of UV radiation-induced photo damage

Mitigation of Nitrogen Mustard-Induced Skin Injury by the β-Blocker Carvedilol and Its Enantiomers.

The chemical warfare agent sulfur mustard and its structural analog nitrogen mustard (NM) cause severe vesicating skin injuries. The pathologic mechanisms for the skin injury following mustard exposure are poorly understood; therefore, no effective countermeasure is available. Previous reports demonstrated the protective activity of carvedilol, a US Food and Drug Administration (FDA)-approved β-blocker, against UV radiation-induced skin damage. Thus, the current study evaluated the effects of carvedilol on NM-induced skin injuries in vitro and in vivo. In the murine epidermal cell line JB6 Cl 41-5a, β-blockers with different receptor subtype selectivity were examined. Carvedilol and both of its enantiomers, R- and S-carvedilol, were the only tested ligands statistically reducing NM-induced cytotoxicity. Carvedilol also reduced NM-induced apoptosis and p53 expression. In SKH-1 mice, NM increased epidermal thickness, damaged skin architecture, and induced nuclear factor κB (NF-κB)-related proinflammatory genes as assessed by RT2 Profiler PCR (polymerase chain reaction) Arrays. To model chemical warfare scenario, 30 minutes after exposure to NM, 10 μM carvedilol was applied topically. Twenty-four hours after NM exposure, carvedilol attenuated NM-induced epidermal thickening, Ki-67 expression, a marker of cellular proliferation, and multiple proinflammatory genes. Supporting the in vitro data, the non-β-blocking R-enantiomer of carvedilol had similar effects as racemic carvedilol, and there was no difference between carvedilol and R-carvedilol in the PCR array data, suggesting that the skin protective effects are independent of the β-adrenergic receptors. These data suggest that the β-blocker carvedilol and its enantiomers can be repurposed as countermeasures against mustard-induced skin injuries. SIGNIFICANCE STATEMENT: The chemical warfare agent sulfur mustard and its structural analog nitrogen mustard cause severe vesicating skin injuries for which no effective countermeasure is available. This study evaluated the effects of US Food and Drug Administration (FDA)-approved β-blocker carvedilol on nitrogen mustard-induced skin injuries to repurpose this cardiovascular drug as a medical countermeasure.

Natural Sun-Screening Compounds and DNA-Repair Enzymes: Photoprotection and Photoaging

Ultraviolet radiation (UVR) has been scientifically proven to cause skin disorders such as sunburn, skin cancer and the symptoms of chronic exposure. Natural sun screening compounds have recently gained tremendous attention from the cosmetic and cosmeceutical sectors for treating skin disorders such as hyperpigmentation and aging. A wide range of natural UV-absorbing compounds have been used to replace or reduce the number of synthetic sunscreen molecules. One of the primary causes of photoaging is DNA damage, mainly caused by UVR. Photoprotection provided by traditional sunscreens is purely preventative and has no efficacy after DNA damage has been initiated. As a result, the quest for DNA-repair mechanisms that block, reverse, or postpone pathologic processes in UV-exposed skin has stimulated anti-photoaging research and methods to increase the effectiveness of traditional sunscreens. This review summarizes many natural compounds from microalgae, lichens, and plants that have demonstrated potential photoprotection effects against UV radiation-induced skin damage. Furthermore, it offers an overview of current breakthroughs in DNA-repair enzymes utilized in sunscreens and their influence on photoaging.

Xeroderma Pigmentosum: A Genetic Condition Skin Cancer Correlated-A Systematic Review.

Background Xeroderma pigmentosum (XP) is a rare autosomal recessive disorder of UV radiation-induced damage repair that is characterized by photosensitivity and a propensity for developing, among many others, skin cancers at an early age. This systematic review focused on the correlation between the clinical, pathological, and genetic aspects of XP and skin cancer. Methods A systematic review was conducted through a literature search of online databases PubMed, Cochrane Library, SciELO, and Google Scholar. Search terms were “Xeroderma pigmentosum”, “XP”, “XPC”, “Nucleotide excision repair”, “NER”, “POLH”, “Dry pigmented skin”, and “UV sensitive syndrome” meshed with the terms “Skin cancer”, “Melanoma”, and “NMSC”. Results After 504 abstracts screening, 13 full-text articles were assessed for eligibility, and 3 of them were excluded. Ten articles were selected for qualitative assessment. Conclusions Patients with XP usually suffer shorter lives due to skin cancer and neurodegenerative disease. Deletion/alteration of a distinct gene allele can produce different types of cancer. The XPC and XP-E variants are more likely to have skin cancer than patients in other complement groups, and the most common cause of death for these patients is skin cancer (metastatic melanoma or invasive SCC). Still, aggressive preventative measures to minimize UV radiation exposure can retard the course of the disease and improve the quality of life.

Hesperetin-Based Hydrogels Protect the Skin against UV Radiation-Induced Damage.

UV radiation can cause damages, such as erythema, skin photoaging, and carcinogenesis. The adoption of protective measures against sun exposure is essential to prevent these damages, and the interest in using natural substances as an alternative for photoprotection is growing. Thus, hesperetin with antioxidant, anti-inflammatory, and anticancer properties is a promising substance to be used with photochemopreventive action and to protect the skin from damage induced by UV radiation. Therefore, the present study aimed to develop a topical formulation based on AAMVPC gel containing hesperetin and evaluate its photoprotective effect on the skin of rats exposed to UVA-UVB radiation. The animals were submitted to the irradiation protocol UVA-UVB, and at the end, erythema, lipid peroxidation, and activity of the antioxidant enzyme catalase and superoxide dismutase were evaluated. Additionally, it evaluated the activity of myeloperoxidase and histological changes. The formulation presented a rheological and spreadability profile suitable for cutaneous application. In vivo results demonstrated that the topical formulation of AAMVPC gel containing hesperetin at a concentration of 10% protected the skin from damage induced by UVA-UVB radiation, with the absence of erythema, lipid lipoperoxidation, and inflammation (low myeloperoxidase activity), and increased catalase and superoxide dismutase activities. The morphology and architecture of the dermo-epidermal tissue of these animals were like those observed under normal conditions (non-irradiated animals). Thus, the results showed that hesperetin was able to protect the animals' skin against UV radiation-induced skin damage and the protection mechanisms may be related to the antioxidant and anti-inflammatory properties of this natural product.

In Vitro Anti-Photoaging and Skin Protective Effects of Licania macrocarpa Cuatrec Methanol Extract.

The Licania genus has been used in the treatment of dysentery, diabetes, inflammation, and diarrhea in South America. Of these plants, the strong anti-inflammatory activity of Licania macrocarpa Cuatrec (Chrysobalanaceae) has been reported previously. However, the beneficial activities of this plant on skin health have remained unclear. This study explores the protective activity of a methanol extract (50–100 μg/mL) in the aerial parts of L. macrocarpa Cuatrec (Lm-ME) and its mechanism, in terms of its moisturizing/hydration factors, skin wrinkles, UV radiation-induced cell damage, and radical generation (using RT/real-time PCR, carbazole assays, flowcytometry, DPPH/ABTS, and immunoblotting analysis). The anti-pigmentation role of Lm-ME was also tested by measuring levels of melanin, melanogenesis-related genes, and pigmentation-regulatory proteins. Lm-ME decreased UVB-irradiated death in HaCaT cells by suppressing apoptosis and inhibited matrix metalloproteinases 1/2 (MMP1/2) expression by enhancing the activity of extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38. It was confirmed that Lm-ME displayed strong antioxidative activity. Lm-ME upregulated the expression of hyaluronan synthases-2/3 (HAS-2/3) and transglutaminase-1 (TGM-1), as well as secreted levels of hyaluronic acid (HA) via p38 and JNK activation. This extract also significantly inhibited the production of hyaluronidase (Hyal)-1, -2, and -4. Lm-ME reduced the melanin expression of microphthalmia-associated transcription factor (MITF), tyrosinase, and tyrosinase-related protein-1/2 (TYRP-1/2) in α-melanocyte-stimulating hormone (α-MSH)-treated B16F10 cells via the reduction of cAMP response element-binding protein (CREB) and p38 activation. These results suggest that Lm-ME plays a role in skin protection through antioxidative, moisturizing, cytoprotective, and skin-lightening properties, and may become a new and promising cosmetic product beneficial for the skin.

Effect of a Metal Ion in Modulating the Binding Interaction of a Dietary Flavonoid with Bovine Serum Albumin and DNA: A Spectroscopic and Theoretical Approach

Plant-derived flavonoids are an excellent option as a potential substitute to synthetic products in food industries, and flavonoid–metal complexes exhibit better functional properties than free flavonoids. Here, an iron(II) complex of rutin, a dietary flavonoid, has been synthesized and characterized. A comparative assessment of the interaction of rutin and its iron(II) complex with the transport protein [bovine serum albumin (BSA)] and deoxyribonucleic acid (DNA) has been performed. The interaction process has been characterized using multispectroscopic techniques and has been further supported by theoretical studies. We have evidenced the alteration in the interacting mode of rutin with BSA upon complexation with Fe(II). Also, rutin interacts with DNA via minor groove binding, while the complex interacts with DNA through a mixed mode involving both groove binding and intercalative binding. Interestingly, the antioxidant activity of the metal complex has been found to be enhanced, and it also provides better protection against UV radiation-induced cell damage than rutin alone.

Role of distinct fibroblast lineages and immune cells in dermal repair following UV radiation-induced tissue damage.

Solar ultraviolet radiation (UVR) is a major source of skin damage, resulting in inflammation, premature ageing, and cancer. While several UVR-induced changes, including extracellular matrix reorganisation and epidermal DNA damage, have been documented, the role of different fibroblast lineages and their communication with immune cells has not been explored. We show that acute and chronic UVR exposure led to selective loss of fibroblasts from the upper dermis in human and mouse skin. Lineage tracing and in vivo live imaging revealed that repair following acute UVR is predominantly mediated by papillary fibroblast proliferation and fibroblast reorganisation occurs with minimal migration. In contrast, chronic UVR exposure led to a permanent loss of papillary fibroblasts, with expansion of fibroblast membrane protrusions partially compensating for the reduction in cell number. Although UVR strongly activated Wnt signalling in skin, stimulation of fibroblast proliferation by epidermal β-catenin stabilisation did not enhance papillary dermis repair. Acute UVR triggered an infiltrate of neutrophils and T cell subpopulations and increased pro-inflammatory prostaglandin signalling in skin. Depletion of CD4- and CD8-positive cells resulted in increased papillary fibroblast depletion, which correlated with an increase in DNA damage, pro-inflammatory prostaglandins, and reduction in fibroblast proliferation. Conversely, topical COX-2 inhibition prevented fibroblast depletion and neutrophil infiltration after UVR. We conclude that loss of papillary fibroblasts is primarily induced by a deregulated inflammatory response, with infiltrating T cells supporting fibroblast survival upon UVR-induced environmental stress.

Punicalagin Protects Human Retinal Pigment Epithelium Cells from Ultraviolet Radiation-Induced Oxidative Damage by Activating Nrf2/HO-1 Signaling Pathway and Reducing Apoptosis.

The oxidative damage of the retinal pigment epithelium (RPE) is the early event that underlies the pathogenesis of maculopathies. Numerous studies have shown that punicalagin (PUN), a polyphenol present in pomegranate, can protect several cell types from oxidative stress. Our study aims to establish if PUN protects RPE from UV radiation-induced oxidative damage. We used an experimental model which involves the use of a human-RPE cell line (ARPE-19) exposed to UV-A radiation for 1, 3, and 5 h. ARPE-19 cells were pre-treated with PUN (24 h) followed by UV-A irradiation; controls were treated identically, except for UV-A. Effects of pre-treatment with PUN on cell viability, intracellular reactive oxygen species ROS levels, modulation of Nrf2 and its antioxidant target genes, and finally apoptosis were examined. We found that pre-treatment with PUN: (1) antagonized the decrease in cell viability and reduced high levels of ROS associated with UV-A-induced oxidative stress; (2) activated Nrf2 signaling pathway by promoting Nrf2 nuclear translocation and upregulating its downstream antioxidant target genes (HO-1 and NQO1); (3) induced an anti-apoptotic effect by decreasing Bax/Bcl-2 ratio. These findings provide the first evidence that PUN can prevent UV-A-induced oxidative damage in RPE, offering itself as a possible antioxidant agent capable of contrasting degenerative eye diseases.

Ameliorating effect of quercetin against UV radiation-induced damage in Drosophila melanogaster

Quercetin is a plant flavonoid found in various fruits, leaves such as tea, vegetables and has been extensively studied due to its antioxidative, anticancer, anti-inflammatory and anti-neurodegenarative effects. UV radiation is harmful for human being as it may cause several complications such as skin cancer. Fruit fly (Drosophila sp.) has long been used as an arthropod model for genetics related studies. In the present study, the protective effect of quercetin is evaluated against UV-C radiation induced damage using Drosophila melanogaster. Pre-treatment with quercetin (10 µM) recovered the shortened lifespan caused by UV radiation and has also increased eclosion rate and the dose of quercetin is lower than the previously reported doses of other flavonoids. Flies subjected to moderate dose of UV radiation showed distinct abnormal characters such as incomplete abdominal pigmentation, curly wings or outstretched wings, whereas quercetin pretreatment showed no such abnormal characters or mutant phenotypes. There is a considerable amount of change in the eclosed adult fly size, pupal size and pupal migration distance as well. Gel electrophoresis study of salivary gland DNA of D. melanogaster demonstrates the efficacy of quercetin in conferring protection to DNA against UV radiation-induced damage. Therefore, it can be concluded that quercetin may act as an effective protective agent against UV radiation-induced damage. DOI: http://dx.doi.org/10.5281/zenodo.3588543

Epha2 genotype influences ultraviolet radiation induced cataract in mice

Age-related cataract is the major cause of blindness worldwide. Both genetic and environmental factors contribute to the disease. Genetic variation in the Ephrin type-A receptor 2 (EPHA2) gene is associated with the risk of age-related cataract in multiple populations, and exposure to ultraviolet-B (UV–B) radiation is a well-established risk factor for the disease. Epha2 knockout and UV-B radiation independently lead to cataract in mice, and UV-B radiation reportedly alters EPHA2 expression in cultured cells. We hypothesised that an interaction between UV-B radiation exposure and Epha2 signalling may influence cataract development. To test this hypothesis, 5-week-old Epha2+/+ and Epha2+/− mice (n = 8 per group) were exposed to repeated below-threshold doses of UV-B radiation (0.0125–0.05 J/cm2), before development of Epha2-mediated cataract. Cataract development was monitored after termination of exposure and at least one month later. Histological analysis of exposed and unexposed lenses was performed to assess pathological changes, and gene expression analysis to investigate the mechanism underlying cataract. Both Epha2+/+ and Epha2+/− mice developed UV-B dose-dependent anterior polar cataract; cataract severity in both genotypes of mice exposed to either 0.025 or 0.05 J/cm2 UV-B was significantly higher than that in matched unexposed mice (p < 0.05). Histological analysis of lenses of both genotypes of mice exposed to 0.025 or 0.05 J/cm2 UV-B radiation consistently revealed disruption of the lens architecture. A month after the exposure, cataract severity increased in Epha2+/+ mice treated with the highest dose of UV-B radiation (p = 0.03) but remained unchanged in Epha2+/− mice. Gene expression analysis of lenses of both genotypes of mice showed significant upregulation of the cell proliferation marker Mki67 in Epha2+/+ (p = 0.036) but not in Epha2+/− mice exposed to the highest dose of UV-B radiation compared to matched unexposed mice. In conclusion, this study suggests that repeated exposure to doses of UV-B radiation lower than the single minimum dose required for inducing cataract leads to cataract in wild-type and Epha2 heterozygous knockout mice. Furthermore, this study indicates, for the first time, a potentially favourable effect of partial Epha2 deficiency against UV radiation-induced damage in the lens.

Characterization and engineering of a carotenoid biosynthesis operon from Bacillus megaterium

Bacillus megaterium belongs to the group of pigmented bacilli producing carotenoids that ensure self-protection from UV radiation-induced and collateral oxidative damage. Metabolite profiling of strain MS941 revealed the presence of the C30 carotenoids 4,4′-diapophytofluene and 4,4′-diaponeurosporenic acid. A gene function analysis demonstrated the presence of a corresponding C30 carotenoid biosynthetic pathway with pharmaceutical importance. We identified a gene cluster comprising putative genes for a farnesyl diphosphate synthase (IspA), a diapophytoene synthase (CrtM) and three distinct diapophytoene desaturases (CrtN1–3). Intriguingly, crtM was organized in an operon together with two of the identified crtN genes. The individual activities of the encoded enzymes were determined by heterologous expression and product analysis in the non-carotenogenic model organism Escherichia coli. Our experimental data show that the first catalytic steps of C30 carotenoid biosynthesis in B. megaterium share significant similarity to the corresponding biosynthetic pathway of Staphylococcus aureus. The biosynthesis of farnesyl diphosphates and their subsequent condensation to form 4,4′-diapophytoene are catalyzed by the identified IspA and CrtM, respectively. The following desaturation reactions to form 4,4′-diaponeurosporene, however, require the activities of multiple diapophytoene desaturases. A biosynthetic operon was engineered and successfully expressed in an E. coli whole-cell system creating a cell factory for a high-yield production of the C30 carotenoid 4,4′-diaponeurosporene which has promising potential in the treatment of various inflammatory diseases.

Anti-melanogenic activity of schaftoside in Rhizoma Arisaematis by increasing autophagy in B16F1 cells

Skin pigmentation involves multiple processes, including melanin synthesis, transport, and melanosome release. Melanin content determines skin color and protects against UV radiation-induced damage. Autophagy is a cooperative process between autophagosomes and lysosomes that degrades cellular components and organelles. In the present study, B16F1 cells were treated with Rhizoma Arisaematis extract (RA) and assessed for pigmentation and autophagy regulation. RA treatment suppressed the α-MSH-stimulated increase of melanogenesis and down-regulated the expression of tyrosinase and TRP1 proteins in B16F1 cells. In addition, autophagy was activated in RA-treated cells. Inhibition of autophagy reduced the anti-melanogenic activity of RA in α-MSH-treated B16F1 cells. We identified schaftoside as an effector molecule by LC-MS analysis of RA. Consistently, treatment of schaftoside showed anti-melanogenic effect and induced autophagy activation in B16F1 cells. Inhibition of autophagy by 3 MA treatment reduced the anti-melanogenic effect of the schaftoside and recovered expression level of melanogenesis regulators in α-MSH-treated B16F1 cells. Taken together, our results suggest that schaftoside from RA inhibits skin pigmentation through modulation of autophagy.

Advances in Immunotherapy for Metastatic Merkel Cell Carcinoma: A Clinician's Guide.

Merkel cell carcinoma (MCC) is a neuroendocrine skin cancer. The clinical impact of MCC has been increasing due to steadily rising incidence rates. Since 2001, more than 24,000 cases of MCC have been reported to the US National Program of Cancer Registries database, and in 2018, more than 2,500 incident cases are expected. MCC is highly aggressive, and one-third of patients will either present with or develop metastatic disease. Outcomes in patients with metastatic MCC have historically been poor; median time to progression with cytotoxic chemotherapy is only 3 months. MCC has long been appreciated to be immunogenic, with reports of spontaneous regression and responsiveness to immunotherapy. However, the mechanisms of this immunogenicity have only been understood over the past decade, with approximately 80% of cases in the United States associated with the Merkel cell polyomavirus (MCPyV) and expression of viral antigens (virus-positive [VP] MCC), and the remaining 20% of cases caused by UV radiation-induced damage leading to a high mutational burden and expression of neoantigens (virus-negative [VN] MCC). These insights have led to multiple successful trials of immunotherapies for MCC. PD-1 axis checkpoint inhibitors are now regarded as the preferred frontline systemic therapy in eligible patients (including both VP- and VN-MCC), with impressive frequency, durability, and depth of objective responses, which compare favorably to those of most solid tumors. This article reviews the safety and efficacy data from the key clinical trials of immune checkpoint inhibitors for metastatic MCC, and discusses several issues relevant to the clinical use of these agents. Finally, emerging immunotherapies for MCC, including cellular therapies and adjuvant systemic therapies, are reviewed.

Orobanche cernua Loefling Attenuates Ultraviolet B-mediated Photoaging in Human Dermal Fibroblasts.

UV radiation is the primary cause of skin photoaging, which results in an increase in matrix metalloproteinases and degradation of collagen. Developing new natural antioxidant as photoprotective agents has become a popular area of research. Orobanche cernua Loefling is a parasitic plant that is rich in phenylethanoid glycosides (PhGs). This study investigated the photoprotective effects of the ethanolic extract of Orobanche cernua Loefling (OC) and its principal component acteoside on UVB-induced photoaging as well as their underlying molecular mechanisms in normal human dermal fibroblasts (NHDFs). Biological testing demonstrated that OC and acteoside possessed significant photoprotective activities, reducing MMP and IL-6 levels while improving type-I procollagen synthesis in UVB-irradiated NHDFs. Further study showed that the protective mechanisms were the improvement of transcription factor Nrf2-mediated antioxidant defensive system, suppression of MAPK/AP-1 and activation of the TGF-β/Smad pathway. Together, our results suggested that OC might be a promising antiphotoaging agent against UV radiation-induced skin damage.

UV radiation induces a gene's dual functionality.

A protein and noncoding RNA encoded by the same gene have opposing roles in the response to UV radiation-induced damage.

Hesperidin ameliorates UV radiation-induced skin damage by abrogation of oxidative stress and inflammatory in HaCaT cells

Ultraviolet A (UVA) radiation contributes to skin photoaging. Hesperidin which is a flavanone glycoside found in citrus fruit peels, have been intensively studied for their UVA-protective activity, but its effects and mechanisms on UVA irradiation-induced inflammation and oxidative stress have never been described. Thus, the purpose of this study was to evaluate the effects of hesperidin in skin oxidative stress and inflammation induced by UVA irradiation. In this study, we firstly examined whether hesperidin may exert direct protective effects on the UVA-induced in human keratinocytes (HaCaT) cell injury in vitro. Cell viability was determined by MTT assay. The levels of superoxide dismutase (SOD), malondialdehyde (MDA) and total antioxidative capacity (T-AOC) were measured by using a commercially available kits. Quantitative reverse transcriptase PCR (qRT-PCR) and ELISA were used to determine messenger RNA (mRNA) and protein levels of the tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6. UVA significantly decreased the cell viability (P<0.05). In our study, hesperidin (220μg/ml) significantly reduced UVA-induced oxidative stress and inflammatory response. In conclusion, hesperidin treatment effectively protected HaCaT keratinocytes from these UVA radiation-induced skin injuries, suggesting that the underlying mechanism involves the anti-oxidative and anti-inflammatory capacities, it is possible to be used as a sunscreen agent.