The dark side of daylight: photoaging and the tumor microenvironment in melanoma progression

Selenomethionine in gelatin methacryloyl hydrogels: Modulating ferroptosis to attenuate skin aging

During skin aging, the degeneration of epidermal stem cells (EpiSCs) leads to diminished wound healing capabilities and epidermal disintegration. This study tackles this issue through a comprehensive analysis combining transcriptomics and untargeted metabolomics, revealing age-dependent alterations in the Gpx gene family and arachidonic acid (AA) metabolic networks, resulting in enhanced ferroptosis. Selenomethionine (Se-Met) could enhance GPX4 expression, thereby assisting EpiSCs in countering AA-induced mitochondrial damage and ferroptosis. Additionally, Se-Met demonstrates antioxidative characteristics and extensive ultraviolet absorption. For the sustained and controllable release of Se-Met, it was covalently grafted to UV-responsive GelMA hydrogels via AC-PEG-NHS tethers. The Se-Met@GelMA hydrogel effectively accelerated wound healing in a chronological aging mice model, by inhibiting lipid peroxidation and ferroptosis with augmented GPX4 expression. Moreover, in a photoaging model, this hydrogel significantly mitigated inflammatory responses, extracellular matrix remodeling, and ferroptosis in UV-exposed mice. These characteristics render Se-Met@GelMA hydrogel valuable in practical clinical applications.

Light exposure and its applications in human health

Light exposure has been proven to have a significant impact on human health. As a result, researchers are increasingly exploring its potential benefits and drawbacks. With advancements in understanding light and the manufacturing of light sources, modern health lighting has become widely utilized in daily life and plays a critical role in the prevention and treatment of various illnesses. The use of light in healthcare is a global trend, with many countries actively promoting the development and application of relevant scientific research and medical technology. This field has gained worldwide attention and support from scientists and doctors alike. In this review, we examine the application of lighting in human health and recent breakthroughs in light exposure related to pathology, therapeutic strategies, molecular changes, and more. Finally, we also discuss potential future developments and areas of application.

The correlation between dermoscopy and clinical and pathological tests in the evaluation of skin photoaging

BACKGROUND

There are no standards for evaluating skin photoaging. Dermoscopy is a non-invasive detection method that might be useful for evaluating photoaging.

OBJECTIVE

To assess the correlation between the dermoscopic evaluation of photoaging and clinical and pathological evaluations.

METHODS

The age, clinical evaluation (Fitzpatrick classification, Glogau Photoaging Classification, and Chung's standardized image ruler), histopathology (Masson staining and MMP-1 immunohistochemistry), and dermoscopy (Hu's and Isik's) of 40 donor skin samples were analyzed statistically, and Spearman rank correlation analysis was performed.

RESULTS

There was a robust correlation between the total Hu scores and Isik dermoscopy. The correlation of dermoscopy with histopathology was higher than that of clinical evaluation methods. There is a strong correlation between telangiectases and lentigo. Xerosis, superficial wrinkle, diffuse erythema, telangiectases, and reticular pigmentation were significantly correlated with the three clinical evaluation methods. Superficial wrinkles were correlated with Masson, MMP-1, various clinical indicators, and other dermoscopic items.

CONCLUSION

There is a good correlation between dermoscopy and clinical and histopathological examination. Dermoscopy might help evaluate skin photoaging.

Skin Cancer Microenvironment: What We Can Learn from Skin Aging?

Aging is a natural intrinsic process associated with the loss of fibrous tissue, a slower cell turnover, and a reduction in immune system competence. In the skin, the continuous exposition of environmental factors superimposes extrinsic damage, mainly due to ultraviolet radiation causing photoaging. Although not usually considered a pathogenic event, photoaging affects cutaneous biology, increasing the risk of skin carcinogenesis. At the cellular level, aging is typified by the rise of senescence cells a condition characterized by reduced or absent capacity to proliferate and aberrant hyper-secretory activity. Senescence has a double-edged sword in cancer biology given that senescence prevents the uncontrolled proliferation of damaged cells and favors their clearance by paracrine secretion. Nevertheless, the cumulative insults and the poor clearance of injured cells in the elderly increase cancer incidence. However, there are not conclusive data proving that aged skin represents a permissive milieu for tumor onset. On the other hand, tumor cells are capable of activating resident fibroblasts onto a pro-tumorigenic phenotype resembling those of senescent fibroblasts suggesting that aged fibroblasts might facilitate cancer progression. This review discusses changes that occur during aging that can prime neoplasm or increase the aggressiveness of melanoma and non-melanoma skin cancer.

Single cell transcriptome profiling reveals cutaneous immune microenvironment remodeling by photodynamic therapy in photoaged skin

Background

The immune microenvironment plays a critical role in maintaining skin homeostasis, which is closely related to the dysfunction in photoaged skin such as autoimmunity and tumorigenesis. Several recent studies have demonstrated the efficacy of 5-aminolevulinic acid photodynamic therapy (ALA-PDT) in alleviating photoaging and skin cancer. However, the underlying immune mechanisms and the immune microenvironment change by ALA-PDT remain largely unknown.

Methods

To illustrate the effects of ALA-PDT on immune microenvironment in photoaged skin, single cell RNA sequencing (scRNA-seq) analysis of photoaged skin on the extensor side of the human forearm before and after ALA-PDT was performed. R-packages of Seurat, clusterProfiler, Monocle, CellChat were used for cell clustering, differentially expressed genes analysis, functional annotation, pseudotime analysis and cell-cell communication analysis. The gene sets related to specific functions were extracted from the MSigDB database, which were used to score the functions of immune cells in different states. We also compared our result with published scRNA-seq data of photoaged skin of the eyelids.

Results

The increase score of cellular senescence, hypoxia and reactive oxygen species pathway in immune cells and the decrease of immune receptor activity function and proportion of naive T cells were found in skin photoaging. Moreover, the function of T cell ribosomal synthesis was also impaired or down regulated and function of G2M checkpoint was up regulated. However, ALA-PDT showed promising results in reversing these effects, as it improved the above functions of T cells. The ratio of M1/M2 and percentage of Langerhans cells also decreased with photoaging and increased after ALA-PDT. Additionally, ALA-PDT restored the antigen presentation and migration function of dendritic cells and enhanced cell-cell communication among immune cells. These effects were observed to last for 6 months.

Conclusion

ALA-PDT has potential to rejuvenate immune cells, partially reversed immunosenescence and improved the immunosuppressive state, ultimately remodelling the immune microenvironment in photoaged skin. These results provide an important immunological basis for further exploring strategies to reverse skin photoaging, chronological aging and potentially systemic aging.

Regular use of vitamin D supplement is associated with fewer melanoma cases compared to non-use: a cross-sectional study in 498 adult subjects at risk of skin cancers

There are conflicting results on the role of vitamin D system in cutaneous carcinogenesis. Therefore, it was investigated whether the use of oral vitamin D supplements associates with photoaging, actinic keratoses, pigment cell nevi, and skin cancers. In this cross-sectional study, 498 adults (aged 21-79 years, 253 males, 245 females, 96 with immunosuppression) subjects at risk of any type of skin cancer were examined, and possible confounding factors were evaluated. The subjects were divided into three groups based on their self-reported use of oral vitamin D supplements: non-use, occasional use, or regular use. The serum level of 25-hydroxyvitamin-D3 was analyzed in 260 subjects. In 402 immunocompetent subjects, vitamin D use did not associate with photoaging, actinic keratoses, nevi, basal, and squamous cell carcinoma. In contrast, there were lower percentages of subjects with a history of past or present melanoma (32/177, 18.1% versus 32/99, 32.3%, P  = 0.021) or any type of skin cancer (110/177, 62.1% versus 74/99, 74.7%, P  = 0.027) among regular users compared to non-users. In the logistic regression analysis, the odds ratio for melanoma was 0.447 ( P  = 0.016, 95% confidence interval, 0.231-0.862) among regular users. Furthermore, the investigator-estimated risk class of skin cancers was significantly lower among regular users. Serum 25-hydroxyvitamin-D3 did not show marked associations with skin-related parameters. The results on 96 immunosuppressed subjects were somewhat similar, although the number of subjects was low. In conclusion, regular use of vitamin D associates with fewer melanoma cases, when compared to non-use, but the causality between them is obscure.

Solid SiO2-Sealed Mesoporous Silica for Synergistically Combined Use of Inorganic and Organic Filters to Achieve Safe and Effective Skin Protection from All-Band UV Radiation

To effectively shield the full band of ultraviolet (UV) radiation and provide desirable protection, the combination of inorganic and organic filters was often used to protect human skin from the serious harm of UV exposure. However, the incompatibility of different filters and their mutual negative effect limit the production of multifilter sunscreen. In addition, the hazard of reactive oxygen species (ROS) produced by inorganic filters after UV exposure and the skin permeability of organic filters remain unresolved problems. In this study, titanium dioxide (TiO₂) and diethylamino hydroxybenzoyl hexyl benzoate (DHHB), two kinds of common filters with complementary UV shielding range, were first encapsulated into large mesoporous silica nanoparticles (MSN, ∼300 nm) to obtain MSN-TiO₂ and MSN-DHHB. Also, a SiO₂ coating was then made to seal and stabilize the MSN-TiO₂ and MSN-DHHB. The structure, UV screen function, and safety of the SiO₂-coated filters, MSN-TiO₂@SiO₂ and MSN-DHHB@SiO₂, were evaluated. The good mechanical stability exhibited by the solid SiO₂ layer prevented the release and skin penetration of the sealed DHHB and the photocatalysis of TiO₂. Furthermore, the combination of MSN-TiO₂@SiO₂ and MSN-DHHB@SiO₂ in sunscreen cream showed excellent UV shielding performance on covering the whole UV radiation range without mutual interference. Therefore, coating SiO₂ over MSN is a feasible strategy for entrapping various filters to improve their photostability, preventing skin penetration and ROS generation, and enhancing their compatibility with different sunscreen formulations.

Indoor Versus Outdoor: Does Occupational Sunlight Exposure Increase Melanoma Risk? A Systematic Review

INTRODUCTION

Melanoma is the fifth most common cancer diagnosed in the United States, representing 5.6% of all new cancer cases. There are conflicting reports correlating a relationship between primarily outdoor occupations, associated with increased exposure to direct sunlight, and the incidence of cutaneous melanoma. Our objective was to outline and critically evaluate the relevant literature related to chronic occupational exposure to sunlight and risk of developing cutaneous melanoma.

METHODS

The study protocol for this systematic review was submitted to the International Prospective Register of Systematic Reviews and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. For each relevant study included, the following information was extracted: author names, publication year, study name, study design, age, exposure assessment, outcome, comparison, number of cases, case ascertainment, and descriptive and adjusted statistics. Study quality and evidence certainty was assessed using the Grading of Recommendations, Assessment, Development and Evaluations model.

RESULTS

The initial database search yielded 1629 articles for review and following full-text screening, a total of 14 articles were included for final analysis. Of the studies included, seven articles were retrospective case control and seven were cohort studies. The studies did not report any differences in the likelihood of cutaneous melanoma development based upon membership in the outdoor versus indoor occupation groups included in each study.

CONCLUSIONS

Overall, the articles included in this systematic review did not report an increased risk of developing cutaneous melanoma among individuals with outdoor occupations. Further investigation is required to determine if other occupational or life-style-related risk factors exist, to help support the development of individualized skin screening recommendations and improve the early detection of melanoma in all populations.

TAZ Reduces UVA-mediated Photoaging through Regulates Cell Proliferation in Skin Fibroblasts

The transcriptional co-activator with PDZ-binding motif (TAZ) is a significant transcription factor downstream of the Hippo pathway regulating organ size, tissue regeneration, cell proliferation and apoptosis. Here, we report on TAZ in response to photoaging mediated by repeated UVA irradiation in skin fibroblasts. Continuous UVA irradiation caused a decrease in TAZ and targeted CTGF mRNA and protein expression in fibroblasts, accompanied by reduced cell proliferation, DNA damage, and cell cycle arrest in G1 phase and S phase reduction. Furthermore, P16 and P21 expression levels were increased, whereas Lamin B1 and Lamin A/C expression were decreased as a result of repeated UVA exposure. We further demonstrated that TAZ reduction enables photoaging caused by continuously UVA-irradiated fibroblasts. TAZ overexpression decreases G1 phase, augments the S phase and reduces P16 and P21 protein expression levels in fibroblasts. However, TAZ overexpressing cells exposed to chronic-UVA radiation show induced G1 phase arrest, an S phase reduction, and elevated P16 and P21 protein levels in fibroblasts, compared with TAZ overexpression cells. These findings suggest a novel function of TAZ to reduce photoaging in fibroblasts. This regulation implies that TAZ might be a viable therapeutic target for photoaging or UVA-related skin disorders.

Ginsenoside Rk1 Prevents UVB Irradiation-Mediated Oxidative Stress, Inflammatory Response, and Collagen Degradation via the PI3K/AKT/NF-κB Pathway In Vitro and In Vivo

Long-term exposure to ultraviolet (UV) irradiation, especially UVB, can trigger destructive intracellular effects, including various types of DNA damage, oxidative stress, and inflammatory responses, leading to accelerated skin aging. Ginsenoside Rk1, a rare ginsenoside pertaining to panaxadiol saponins, has been certified to possess underlying anti-inflammatory effects. Nevertheless, the efficiency of Rk1 against the photoaging of human skin and the latent molecular mechanisms are still unclear. Here, UVB-irradiated HaCaT keratinocytes were used as an in vitro model, and UVB-irradiated BALB/c nude mouse dorsal skin was established as an in vivo model to explore the mechanism by which Rk1 protects skin. Consequently, we found that Rk1 administration significantly attenuated oxidative stress by suppressing reactive oxygen species (ROS) overproduction and strengthening the activities of antioxidant enzymes. The UVB-induced inflammatory response was alleviated by Rk1 application via regulation of the secretion of various proinflammatory cytokines. Additionally, western blot assays illustrated that Rk1 intervention inhibited collagen degradation by reducing the expression of matrix metalloproteinases. Further studies revealed that Rk1 could suppress the PI3K/AKT/NF-κB signaling pathways in vitro and in vivo. Molecular docking results indicated that Rk1 might effectively bind to the active pockets of PI3K, AKT, and NF-κB. The PI3K activator 740 Y-P clearly reversed the effects of Rk1 on oxidative stress, the inflammatory response, and collagen degradation in UVB-irradiated HaCaT cells. Moreover, histological and Masson staining verified that the administration of Rk1 to BALB/c nude mice remarkably ameliorated UVB-induced skin roughness, epidermal thickening, collagen fiber arrangement disorder, and wrinkles. Overall, the evidence provided in this study suggested that Rk1 could be applied for the development of effective natural antiphotoaging agents for skin health.

Vegetable-derived indole enhances the melanoma-treating efficacy of chemotherapeutics

Food-drug interaction is an important but overlooked issue. For example, little is known concerning whether or not the chemotherapy of cancers is affected by the well-defined dietary chemicals such as 2-(indol-3-ylmethyl)-3,3'-diindolylmethane (LTr1) derived from daily consumed cruciferous vegetables. This work, inspired by the described melanogenesis reduction by certain indoles, presents that LTr1 mitigates the melanogenesis and thus potentiates the in vitro and in vivo anti-melanoma effectiveness of different chemotherapeutic agents including dacarbazine, vemurafenib, and sorafenib. In B16 melanoma cells, LTr1 was shown to inhibit the melanogenesis by acting towards the regulatory (R) subunit of protein kinase A (PRKAR1a) associated with the phosphorylation of cAMP-response element binding protein (CREB). This allows LTr1 to reduce the expression of melanogenesis-related enzymes such as tyrosinase (TYR), tyrosinase-related protein 1 (TYRP1), and tyrosinase-related protein 2 (TYRP2). Furthermore, LTr1 was addressed to bind to the aryl hydrocarbon receptor (AhR) and up-regulate the expression of CYP1A1 encoding cytochrome P450 1A1, leading to the escalation of reactive oxygen species (ROS) level. The increased ROS generation promotes the cysteine-to-cystine transformation to inhibit the pheomelanogenesis in melanomas. Collectively, the work identifies LTr1 as a new melanogenesis inhibitor that modulates the PKA/CREB/MITF and AhR/CYP1A1/ROS pathways, thereby providing a new option for (re)sensitizing melanomas to chemotherapeutics.

The sculpting of somatic mutational landscapes by evolutionary forces and their impacts on aging-related disease

Aging represents the major risk factor for the development of cancer and many other diseases. Recent findings show that normal tissues become riddled with expanded clones that are frequently driven by cancer‐associated mutations in an aging‐dependent fashion. Additional studies show how aged tissue microenvironments promote the initiation and progression of malignancies, while young healthy tissues actively suppress the outgrowth of malignant clones. Here, we discuss conserved mechanisms that eliminate poorly functioning or potentially malignant cells from our tissues to maintain organismal health and fitness. Natural selection acts to preserve tissue function and prevent disease to maximize reproductive success but these mechanisms wane as reproduction becomes less likely. The ensuing age‐dependent tissue decline can impact the shape and direction of clonal somatic evolution, with lifestyle and exposures influencing its pace and intensity. We also consider how aging‐ and exposure‐dependent clonal expansions of “oncogenic” mutations might both increase cancer risk late in life and contribute to tissue decline and non‐malignant disease. Still, we can marvel at the ability of our bodies to avoid cancers and other diseases despite the accumulation of billions of cells with cancer‐associated mutations.

Focus on the Contribution of Oxidative Stress in Skin Aging

Skin aging is one of the most evident signs of human aging. Modification of the skin during the life span is characterized by fine lines and wrinkling, loss of elasticity and volume, laxity, rough-textured appearance, and pallor. In contrast, photoaged skin is associated with uneven pigmentation (age spot) and is markedly wrinkled. At the cellular and molecular level, it consists of multiple interconnected processes based on biochemical reactions, genetic programs, and occurrence of external stimulation. The principal cellular perturbation in the skin driving senescence is the alteration of oxidative balance. In chronological aging, reactive oxygen species (ROS) are produced mainly through cellular oxidative metabolism during adenosine triphosphate (ATP) generation from glucose and mitochondrial dysfunction, whereas in extrinsic aging, loss of redox equilibrium is caused by environmental factors, such as ultraviolet radiation, pollution, cigarette smoking, and inadequate nutrition. During the aging process, oxidative stress is attributed to both augmented ROS production and reduced levels of enzymatic and non-enzymatic protectors. Apart from the evident appearance of structural change, throughout aging, the skin gradually loses its natural functional characteristics and regenerative potential. With aging, the skin immune system also undergoes functional senescence manifested as a reduced ability to counteract infections and augmented frequency of autoimmune and neoplastic diseases. This review proposes an update on the role of oxidative stress in the appearance of the clinical manifestation of skin aging, as well as of the molecular mechanisms that underline this natural phenomenon sometimes accelerated by external factors.

Advances in the Application of Exosomes Identification Using Surface-Enhanced Raman Spectroscopy for the Early Detection of Cancers

Exosomes are small nanoscale vesicles with a double-layered lipid membrane structure secreted by cells, and almost all types of cells can secrete exosomes. Exosomes carry a variety of biologically active contents such as nucleic acids and proteins, and play an important role not only in intercellular information exchange and signal transduction, but also in various pathophysiological processes in the human body. Surface-enhanced Raman Spectroscopy (SERS) uses light to interact with nanostructured materials such as gold and silver to produce a strong surface plasmon resonance effect, which can significantly enhance the Raman signal of molecules adsorbed on the surface of nanostructures to obtain a rich fingerprint of the sample itself or Raman probe molecules with ultra-sensitivity. The unique advantages of SERS, such as non-invasive and high sensitivity, good selectivity, fast analysis speed, and low water interference, make it a promising technology for life science and clinical testing applications. In this paper, we briefly introduce exosomes and the current main detection methods. We also describe the basic principles of SERS and the progress of the application of unlabeled and labeled SERS in exosome detection. This paper also summarizes the value of SERS-based exosome assays for early tumor diagnosis.

Aging and Cancer: The Waning of Community Bonds

Cancer often arises in the context of an altered tissue landscape. We argue that a major contribution of aging towards increasing the risk of neoplastic disease is conveyed through effects on the microenvironment. It is now firmly established that aged tissues are prone to develop clones of altered cells, most of which are compatible with a normal histological appearance. Such increased clonogenic potential results in part from a generalized decrease in proliferative fitness, favoring the emergence of more competitive variant clones. However, specific cellular genotypes can emerge with reduced cooperative and integrative capacity, leading to disruption of tissue architecture and paving the way towards progression to overt neoplastic phenotypes.