PRP4 Promotes Skin Cancer by Inhibiting Production of Melanin, Blocking Influx of Extracellular Calcium, and Remodeling Cell Actin Cytoskeleton

Prenylated flavonoids from Sophora flavescens inhibit mushroom tyrosinase activity and modulate melanogenesis in murine melanoma cells and zebrafish

Background: Sophora flavescens, a traditional Chinese medicine for treating conditions associated with abnormal skin pigmentation, contains flavonoids with inhibitory effects on tyrosinase. However, their mechanisms of action and their modulatory effects on melanogenesis remain unclear. Methods: Herein, a group of prenylated flavonoids was identified from S. flavescens extracts and their inhibitory activities on mushroom tyrosinase were evaluated. The anti-melanogenesis effects of these prenylated flavonoids were investigated in cellular (with murine melanoma cells) and animal (with zebrafish) models. Results: Prenylated flavonoids including isoanhydroicaritin (IAI), kurarinone (KR), and sophoraflavanone G (SG) were the major active constituents in S. flavescens extracts with anti-tyrosinase activity (IC50 = 0.7, 7.1, and 6.7 μM, respectively). Enzyme kinetic assays showed that IAI, KR, and SG had a mixed type of tyrosinase inhibition, supported by data from computational docking. Notably, KR at concentrations of 5 and 10 μM enhanced intracellular tyrosinase activity and stimulated melanin production in B16F10 cells, whereas SG and IAI did not exhibit significant activity. Further studies with the zebrafish model showed that IAI (80 and 160 μM) inhibited melanin biosynthesis by about 30.0% while KR (20 μM) stimulated melanogenesis by 36.9%. Furthermore, a zebrafish depigmentation model supported the anti-melanogenesis effect of IAI (80 and 160 μM) by 33.0% and 34.4%, respectively. Conclusion: In summary, IAI was identified as a tyrosinase inhibitor with an anti-melanogenic effect and KR was an enhancer for melanin production in B16F10 cells and zebrafish. Findings from the current study suggest that IAI and KR from S. flavescens may exert contrasting effects in the modulation of melanin production, providing important insights into the development of S. flavescens as a cosmeceutical or medicinal ingredient.

Screening out molecular pathways and prognostic biomarkers of ultraviolet-mediated melanoma through computational techniques

PURPOSE

Ultraviolet radiation causes skin cancer, but the exact mechanism by which it occurs and the most effective methods of intervention to prevent it are yet unknown. For this purpose, our study will use bioinformatics and systems biology approaches to discover potential biomarkers of skin cancer for early diagnosis and prevention of disease with applicable clinical treatments.

METHODS

This study compared gene expression and protein levels in ultraviolet-mediated cultured keratinocytes and adjacent normal skin tissue using RNA sequencing data from the National Center for Biotechnology Information-Gene Expression Omnibus (NCBI-GEO) database. Then, pathway analysis was employed with a selection of hub genes from the protein-protein interaction (PPI) network and the survival and expression profiles. Finally, potential clinical biomarkers were validated by receiver operating characteristic (ROC) curve analysis.

RESULTS

We identified 32 shared differentially expressed genes (DEGs) by analyzing three different subsets of the GSE85443 dataset. Skin cancer development is related to the control of several DEGs through cyclin-dependent protein serine/threonine kinase activity, cell cycle regulation, and activation of the NIMA kinase pathways. The cytoHubba plugin in Cytoscape identified 12 hub genes from PPI; among these 3 DEGs, namely, AURKA, CDK4, and PLK1 were significantly associated with survival (P < 0.05) and highly expressed in skin cancer tissues. For validation purposes, ROC curve analysis indicated two biomarkers: AURKA (area under the curve (AUC) value = 0.8) and PLK1 (AUC value = 0.7), which were in an acceptable range.

CONCLUSIONS

Further translational research, including clinical experiments, teratogenicity tests, and in-vitro or in-vivo studies, will be performed to evaluate the expression of these identified biomarkers regarding the prognosis of skin cancer patients.

Comparative transcriptome elucidates key genes and pathways related to golden phenotype of Crassostrea gigas

Marine bivalves are economically important and exhibit a remarkable diversity in shell color. The Pacific oyster Crassostrea gigas stands out as an important economic species, with the successful development of four distinct color strains through selective breeding. While previous studies have shed light on the genetic mechanism underlying color segregation, the precise molecular regulatory mechanisms responsible for shell coloration in oysters remains elusive. In this study, we confirmed that the golden phenotype is primarily attributed to pheomelanin by histological and ultrastructural observations. Additionally, we conducted a comparative transcriptome analysis of the black and golden shell color oysters to explore the potential genes and pathways contributing to the golden phenotype in C. gigas. Our results revealed a significant increase in differentially expressed genes in the golden phenotype associated with pathways such as glutathione metabolism, and calcium signaling pathway, suggesting a potential role in the synthesis of pheomelanin. Of particular note, we highlighted the potential role of two-pore channel 2 (TPC2) in modulating tyrosinase activity and melanosomal pH, ultimately determining the shade of pigmentation. Our study in this work provided a preliminary exploration of the mechanism, shedding light on the melanosome microenvironment and shell color.

A Novel and Versatile Microfluidic Device for Cell Assays under Radio Frequency Exposure

Wound healing is a complex process composed of different stages, which involves extensive communication between the different cellular factors of the extracellular matrix (ECM). The radio frequency electromagnetic field (RF-EMF) has been used to accelerate the wound-healing process and it has been found to enhance cell alignment and mobility. The conventional methods for cell mobility analysis in an electromagnetic field generated by a radiation source are not advisable due to the low-precision, nonuniform distribution of the field, low efficiency of the analysis in batch and the lack of system integration for autonomous on-body operation. Here, a novel and versatile electromagnetic exposure system integrated with a microfluidic chip was fabricated to explore the EMF-induced response. A gradient electromagnetic field in a two-dimensional plane has been successfully established in the microchambers placed along the field line. In this work, by deploying our radiation experiments in vitro, we validated the on-chip monitoring of cell response to exposure. This electromagnetic field was simulated and human amniotic epithelial cells (HAECs) were cultured in different microchambers for continuous exposure to the electromagnetic field excited by a monopole RF antenna (1.8 GHz). New protrusions were generated and an obvious increase in filopodia with the increased field intensity was investigated. Meanwhile, the variation in intracellular Ca2+ concentration under the electromagnetic field was examined. The inhibitory effect of the Ca2+ circulation was further inspected to reveal the potential downstream signaling pathway in the RF-EMF-related bioassay, suggesting that cytoskeletal dynamics of cells under exposure are highly associated with the EGF receptor (EGFR)-cytoskeleton downstream signaling pathway. Finally, the field-induced cell elongation and alignment parallel to the field direction were observed. Additionally, the subsequent recovery (field withdrawal) and re-establishment (field re-exposure) were explored. These results indicated that this reliable and versatile exposure system for bioassay could achieve precise and high-throughput detection of the RF-EMF-induced cytoskeletal reorganization in vitro and evaluate the possible health risk from RF-EMF exposure.

cAMP Signaling in Cancer: A PKA-CREB and EPAC-Centric Approach

Cancer is one of the most common causes of death globally. Despite extensive research and considerable advances in cancer therapy, the fundamentals of the disease remain unclear. Understanding the key signaling mechanisms that cause cancer cell malignancy may help to uncover new pharmaco-targets. Cyclic adenosine monophosphate (cAMP) regulates various biological functions, including those in malignant cells. Understanding intracellular second messenger pathways is crucial for identifying downstream proteins involved in cancer growth and development. cAMP regulates cell signaling and a variety of physiological and pathological activities. There may be an impact on gene transcription from protein kinase A (PKA) as well as its downstream effectors, such as cAMP response element-binding protein (CREB). The position of CREB downstream of numerous growth signaling pathways implies its oncogenic potential in tumor cells. Tumor growth is associated with increased CREB expression and activation. PKA can be used as both an onco-drug target and a biomarker to find, identify, and stage tumors. Exploring cAMP effectors and their downstream pathways in cancer has become easier using exchange protein directly activated by cAMP (EPAC) modulators. This signaling system may inhibit or accelerate tumor growth depending on the tumor and its environment. As cAMP and its effectors are critical for cancer development, targeting them may be a useful cancer treatment strategy. Moreover, by reviewing the material from a distinct viewpoint, this review aims to give a knowledge of the impact of the cAMP signaling pathway and the related effectors on cancer incidence and development. These innovative insights seek to encourage the development of novel treatment techniques and new approaches.

The Role of Calcium Signaling in Melanoma

Calcium signaling plays important roles in physiological and pathological conditions, including cutaneous melanoma, the most lethal type of skin cancer. Intracellular calcium concentration ([Ca²⁺]i), cell membrane calcium channels, calcium related proteins (S100 family, E-cadherin, and calpain), and Wnt/Ca²⁺ pathways are related to melanogenesis and melanoma tumorigenesis and progression. Calcium signaling influences the melanoma microenvironment, including immune cells, extracellular matrix (ECM), the vascular network, and chemical and physical surroundings. Other ionic channels, such as sodium and potassium channels, are engaged in calcium-mediated pathways in melanoma. Calcium signaling serves as a promising pharmacological target in melanoma treatment, and its dysregulation might serve as a marker for melanoma prediction. We documented calcium-dependent endoplasmic reticulum (ER) stress and mitochondria dysfunction, by targeting calcium channels and influencing [Ca²⁺]i and calcium homeostasis, and attenuated drug resistance in melanoma management.