Prevention of Photocarcinogenesis by Agonists of 5-HT1A and Antagonists of 5-HT2A Receptors

A versatile theranostic magnetic polydopamine iron oxide NIR laser-responsive nanosystem containing doxorubicin for chemo-photothermal therapy of melanoma

Theranostics nanoparticles (NPs) have recently received much attention in cancer imaging and treatment. This study aimed to develop a multifunctional nanosystem for the targeted delivery of photothermal and chemotherapy agents. Fe3O4 NPs were modified with polydopamine, bovine serum albumin, and loaded with DOX via a thermal-cleavable Azo linker (Fe3O4@PDA@BSA-DOX). The size of Fe3O4@PDA@BSA NPs was approximately 98 nm under the desired conditions. Because of the ability of Fe3O4 and PDA to convert light into heat, the temperature of Fe3O4@PDA@BSA NPs increased to approximately 47 °C within 10 min when exposed to an 808 nm NIR laser with a power density of 1.5 W/cm2. The heat generated by the NIR laser leads to the breaking of AZO linker and drug release. In vivo and in vitro results demonstrated that prepared NPs under laser irradiation successfully eradicated tumor cells without any significant toxicity effect. Moreover, the Fe3O4@PDA@BSA NPs exhibited the potential to function as a contrasting agent. These NPs could accumulate in tumors with the help of an external magnet, resulting in a significant enhancement in the quality of magnetic resonance imaging (MRI). The prepared novel multifunctional NPs seem to be an efficient system for imaging and combination therapy in melanoma.

PD-L1 Enhanced by cis-Urocanic Acid on Langerhans Cells Inhibits Vγ4+ γδT17 Cells in Psoriatic Skin Inflammation

Psoriasis is an IL-23/IL-17-mediated inflammatory autoimmune dermatosis and ultraviolet B (UVB) may contribute to immunosuppression and ameliorate associated symptoms. One of the pathophysiology underlying UVB therapy is through the production of cis-urocanic acid (cis-UCA) from keratinocytes. However, the detailed mechanism is yet to be fully understood. In the current study, we found filaggrin expression and serum cis-UCA levels were significantly lower in psoriasis patients than in healthy controls. We also noted that cis-UCA application inhibited psoriasiform inflammation through the reduction of Vγ4⁺ γδT17 cells in murine skin and draining lymph nodes. Meanwhile, CCR6 was down-regulated on γδT17 cells, which would suppress the inflammatory reaction at a distal skin site. We revealed that 5-HT_2A receptor (HTR2A), the known cis-UCA receptor, was highly expressed on Langerhans cells (LCs) in the skin. cis-UCA also inhibited IL-23 expression and induced PD-L1 on LCs, leading to the attenuated proliferation and migration of γδT cells. Compared to the isotype control, α-PD-L1 treatment in vivo could reverse the anti-psoriatic effects of cis-UCA. PD-L1 expression on LCs was sustained through cis-UCA-induced MAPK/ERK pathway. These findings uncover the cis-UCA-induced PD-L1-mediated immunosuppression on LCs, which facilitates the resolution of inflammatory dermatoses.

Rapid and simultaneous determination of histidine metabolism intermediates in human and mouse microbiota and biomatrices

Histidine metabolism is a key pathway physiologically involved in satiety, recognition memory, skin, and neural protection and allergic diseases. Microbiologically-produced imidazole propionate induces type II diabetes and interferes with glucose lowering drugs. Despite their determinant health implications, no single method simultaneously assesses histidine metabolites in urine, feces, and microbiota. The aim of this study was to develop a simple, rapid, and sensitive method for the determination of histidine and its major bioactive metabolites histamine, N-acetylhistamine, imidazole-4-acetate, cis-urocanate, trans-urocanate, glutamate and imidazole propionate, using ultrahigh-performance liquid chromatography with electrospray ionization tandem mass spectrometry. An innovative simple extraction method from small aliquots of human and mice urine, feces and microbial cell extracts was coupled to separation in a 6.5 min chromatographic run. The successful performance allowed accurate and precise quantification of all metabolites in mouse feces, suggesting broad exchange of histidine metabolites between the gut and mice. Higher urine histamine, histamine to histidine ratio, and imidazole-4-acetate pointed to an underlying inflammatory or allergic process in mice compared to human subjects. N-acetylhistamine and imidazole propionate were detected in human and mouse feces, confirming its origin from gut microbial metabolism. Our novel and robust analytical method captured histidine metabolism in a single assay that will facilitate broad and deep histidine metabolic phenotyping assessing the impact of microbiota on host health in large-scale human observational and interventional studies.

Hyperthermia Enhances Doxorubicin Therapeutic Efficacy against A375 and MNT-1 Melanoma Cells

Melanoma is the deadliest form of skin cancer, and its incidence has alarmingly increased in the last few decades, creating a need for novel treatment approaches. Thus, we evaluated the combinatorial effect of doxorubicin (DOX) and hyperthermia on A375 and MNT-1 human melanoma cell lines. Cells were treated with DOX for 24, 48, and 72 h and their viabilities were assessed. The effect of DOX IC10 and IC20 (combined at 43 °C for 30, 60, and 120 min) on cell viability was further analyzed. Interference on cell cycle dynamics, reactive oxygen species (ROS) production, and apoptosis upon treatment (with 30 min at 43 °C and DOX at the IC20 for 48 h) were analyzed by flow cytometry. Combined treatment significantly decreased cell viability, but not in all tested conditions, suggesting that the effect depends on the drug concentration and heat treatment duration. Combined treatment also mediated a G2/M phase arrest in both cell lines, as well as increasing ROS levels. Additionally, it induced early apoptosis in MNT-1 cells, while in A375 cells this effect was similar to the one caused by hyperthermia alone. These findings demonstrate that hyperthermia enhances DOX effect through cell cycle arrest, oxidative stress, and apoptotic cell death.

Proteome Analysis of USP7 Substrates Revealed Its Role in Melanoma Through PI3K/Akt/FOXO and AMPK Pathways

The ubiquitin-specific protease 7 (USP7), as a deubiquitinating enzyme, plays an important role in tumor progression by various mechanisms and serves as a potential therapeutic target. However, the functional role of USP7 in melanoma remains elusive. Here, we found that USP7 is overexpressed in human melanoma by tissue microarray. We performed TMT-based quantitative proteomic analysis to evaluate the A375 human melanoma cells treated with siRNA of USP7. Our data revealed specific proteins as well as multiple pathways and processes that are impacted by USP7. We found that the phosphatidylinositol-3-kinases/Akt (PI3K-Akt), forkhead box O (FOXO), and AMP-activated protein kinase (AMPK) signaling pathways may be closely related to USP7 expression in melanoma. Moreover, knockdown of USP7 in A375 cells, particularly USP7 knockout using CRISPR-Cas9, verified that USP7 regulates cell proliferation in vivo and in vitro. The results showed that inhibition of USP7 increases expression of the AMPK beta (PRKAB1), caspase 7(CASP7), and protein phosphatase 2 subunit B R3 isoform (PPP2R3A), while attenuating expression of C subunit of vacuolar ATPase (ATP6V0C), and peroxisomal biogenesis factor 11 beta (PEX11B). In summary, these findings reveal an important role of USP7 in regulating melanoma progression via PI3K/Akt/FOXO and AMPK signaling pathways and implicate USP7 as an attractive anticancer target for melanoma.

Encapsulation and Enhanced Release of Resveratrol from Mesoporous Silica Nanoparticles for Melanoma Therapy

Chemotherapy has limited success in the treatment of malignant melanoma due to fast development of drug resistance and the low bioavailability of chemotherapeutic drugs. Resveratrol (RES) is a natural polyphenol with recognized preventive and therapeutic anti-cancer properties. However, poor RES solubility hampers its bioactivity, thus creating a demand for suitable drug delivery systems to improve it. This work aimed to assess the potential of RES-loaded mesoporous silica nanoparticles (MSNs) for human melanoma treatment. RES was efficiently loaded (efficiency > 93%) onto spheroidal (size~60 nm) MSNs. The encapsulation promoted the amorphization of RES and enhanced the release in vitro compared to non-encapsulated RES. The RES release was pH-dependent and markedly faster at pH 5.2 (acid environment in some tumorous tissues) than at pH 7.4 in both encapsulated and bulk forms. The RES release from loaded MSNs was gradual with time, without a burst effect, and well-described by the Weibull model. In vitro cytotoxicity studies on human A375 and MNT-1 melanoma cellular cultures showed a decrease in the cell viability with increasing concentration of RES-loaded MSNs, indicating the potent action of the released RES in both cell lines. The amelanotic cell line A375 was more sensitive to RES concentration than the melanotic MNT-1 cells.

The Brain-Skin Connection and the Pathogenesis of Psoriasis: A Review with a Focus on the Serotonergic System

Psoriasis is a common non-communicable chronic immune-mediated skin disease, affecting approximately 125 million people in the world. Its pathogenesis results from a combination of genetic and environmental factors. The pathogenesis of psoriasis seems to be driven by the interaction between innate immune cells, adaptive immune cells and keratinocytes, in a process mediated by cytokines (including interleukins (IL)-6, IL-17 and IL-22, interferon and tumor necrosis factor) and other signaling molecules. This leads to an inflammatory process with increased proliferation of epidermal cells, neo-angiogenesis and infiltration of dendritic cells in the skin. Dysfunctional de novo glucocorticoid synthesis in psoriatic keratinocytes and the skin microbiome have also been suggested as mediators in the pathogenesis of this disease. To understand psoriasis, it is essential to comprehend the processes underlying the skin immunity and neuroendocrinology. This review paper focuses on the skin as a neuroendocrine organ and summarizes what is known about the skin immune system, the brain-skin connection and the role played by the serotonergic system in skin. Subsequently, the alterations of neuroimmune processes and of the serotonergic system in psoriatic skin are discussed, as well as, briefly, the genetic basis of psoriasis.

Dose and time effects of solar-simulated ultraviolet radiation on the in vivo human skin transcriptome

Background

Terrestrial ultraviolet (UV) radiation causes erythema, oxidative stress, DNA mutations and skin cancer. Skin can adapt to these adverse effects by DNA repair, apoptosis, keratinization and tanning.

Objectives

To investigate the transcriptional response to fluorescent solar‐simulated radiation (FSSR) in sun‐sensitive human skin in vivo.

Methods

Seven healthy male volunteers were exposed to 0, 3 and 6 standard erythemal doses (SED). Skin biopsies were taken at 6 h and 24 h after exposure. Gene and microRNA expression were quantified with next generation sequencing. A set of candidate genes was validated by quantitative polymerase chain reaction (qPCR); and wavelength dependence was examined in other volunteers through microarrays.

Results

The number of differentially expressed genes increased with FSSR dose and decreased between 6 and 24 h. Six hours after 6 SED, 4071 genes were differentially expressed, but only 16 genes were affected at 24 h after 3 SED. Genes for apoptosis and keratinization were prominent at 6 h, whereas inflammation and immunoregulation genes were predominant at 24 h. Validation by qPCR confirmed the altered expression of nine genes detected under all conditions; genes related to DNA repair and apoptosis; immunity and inflammation; pigmentation; and vitamin D synthesis. In general, candidate genes also responded to UVA1 (340–400 nm) and/or UVB (300 nm), but with variations in wavelength dependence and peak expression time. Only four microRNAs were differentially expressed by FSSR.

Conclusions

The UV radiation doses of this acute study are readily achieved daily during holidays in the sun, suggesting that the skin transcriptional profile of ‘typical’ holiday makers is markedly deregulated.

What's already known about this topic?

The skin's transcriptional profile underpins its adverse (i.e. inflammation) and adaptive molecular, cellular and clinical responses (i.e. tanning, hyperkeratosis) to solar ultraviolet radiation.

Few studies have assessed microRNA and gene expression in vivo in humans, and there is a lack of information on dose, time and waveband effects.

What does this study add?

Acute doses of fluorescent solar‐simulated radiation (FSSR), of similar magnitude to those received daily in holiday situations, markedly altered the skin's transcriptional profiles.

The number of differentially expressed genes was FSSR‐dose‐dependent, reached a peak at 6 h and returned to baseline at 24 h.

The initial transcriptional response involved apoptosis and keratinization, followed by inflammation and immune modulation. In these conditions, microRNA expression was less affected than gene expression.

Linked Comment:Hart. Br J Dermatol 2020; 182:1328–1329.

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Cytotoxic effect of the serotonergic drug 1-(1-Naphthyl)piperazine against melanoma cells

1-(1-Naphthyl)piperazine (1-NPZ) is a serotonergic derivative of quipazine acting both as antagonist and agonist of different serotonin receptors, with promising results for the management of skin cancer. In this work, we studied the effect of 1-NPZ on human MNT-1 melanoma cells by evaluating its effects on cell viability, ability to form colonies, cell cycle dynamics, reactive oxygen species (ROS) production and apoptosis. Treatment of MNT-1 cells with 1-NPZ for 24h decreased cell viability and induced apoptosis in a dose-dependent manner. Activity against melanoma was confirmed with a different melanoma cell line, SK-MEL-28. Simultaneously, 1-NPZ affected cell cycle progression by mediating a S-phase delay. Higher levels of ROS were also detected in MNT-1 cells after treatment with 1-NPZ. Furthermore, 1-NPZ significantly increased the expression of cyclooxygenase-2 in MNT-1 cells. These findings suggest that 1-NPZ pretreatment is able to induce oxidative stress, and consequently apoptotic cell death in melanoma cells. In conclusion, this study demonstrates the cytotoxic and genotoxic potential of 1-NPZ against melanoma cells.