Baicalein Inhibits the Migration and Invasion of B16F10 Mouse Melanoma Cells through Inactivation of the PI3K/Akt Signaling Pathway

The most recent progress of baicalein in its anti-neoplastic effects and mechanisms

Problems, such as toxic side effects and drug resistance of chemoradiotherapy, target therapy and immunotherapy accompanying the current anti-cancer treatments, have become bottlenecks limiting the clinical benefit for patients. Therefore, it is urgent to find promising anti-cancer strategies with higher efficacy and lesser side effects. Baicalein, a flavonoid component derived from the Chinese medicine scutellaria baicalensis, has been widely studied for its remarkable anti-cancer activity in multiple types of malignancies both at the molecular and cellular levels. Baicalein exerts its anti-tumor effects by inhibiting angiogenesis, invasion and migration, inducing cell apoptosis and cell cycle arrest, as well as regulating cell autophagy, metabolism, the tumor microenvironment and cancer stem cells with no obvious toxic side effects. The role of classic signaling pathways, such as PI3K/AKT/mTOR, MAPK, AMPK, Wnt/β-catenin, JAK/STAT3, MMP-2/-9, have been highlighted as the major targets for baicalein exerting its anti-malignant potential. Besides, baicalein can regulate the relevant non-coding RNAs, such as lncRNAs, miRNAs and circ-RNAs, to inhibit tumorigenesis and progression. In addition to the mentioned commonalities, baicalein shows some specific anti-tumor characteristics in some specific cancer types. Moreover, the preclinical studies of the combination of baicalein and chemoradiotherapy pave the way ahead for developing baicalein as an adjunct treatment with chemoradiotherapy. Our aim is to summary the role of baicalein in different types of cancer with its mechanisms based on in vitro and in vivo experiments, hoping providing proof for baicalein serving as an effective and safe compound for cancer treatment in clinic in the future.

A Comprehensive Review of Various Therapeutic Strategies for the Management of Skin Cancer

Skin cancer (SC) poses a global threat to the healthcare system and is expected to increase significantly over the next two decades if not diagnosed at an early stage. Early diagnosis is crucial for successful treatment, as the disease becomes more challenging to cure as it progresses. However, identifying new drugs, achieving clinical success, and overcoming drug resistance remain significant challenges. To overcome these obstacles and provide effective treatment, it is crucial to understand the causes of skin cancer, how cells grow and divide, factors that affect cell growth, and how drug resistance occurs. In this review, we have explained various therapeutic approaches for SC treatment via ligands, targeted photosensitizers, natural and synthetic drugs for the treatment of SC, an epigenetic approach for management of melanoma, photodynamic therapy, and targeted therapy for BRAF-mutated melanoma. This article also provides a detailed summary of the various natural drugs that are effective in managing melanoma and reducing the occurrence of skin cancer at early stages and focuses on the current status and future prospects of various therapies available for the management of skin cancer.

The Promising Role of Polyphenols in Skin Disorders

The biochemical characteristics of polyphenols contribute to their numerous advantageous impacts on human health. The existing research suggests that plant phenolics, whether consumed orally or applied directly to the skin, can be beneficial in alleviating symptoms and avoiding the development of many skin disorders. Phenolic compounds, which are both harmless and naturally present, exhibit significant potential in terms of counteracting the effects of skin damage, aging, diseases, wounds, and burns. Moreover, polyphenols play a preventive role and possess the ability to delay the progression of several skin disorders, ranging from small and discomforting to severe and potentially life-threatening ones. This article provides a concise overview of recent research on the potential therapeutic application of polyphenols for skin conditions. It specifically highlights studies that have investigated clinical trials and the use of polyphenol-based nanoformulations for the treatment of different skin ailments.

Antiproliferative, Antiangiogenic, and Antimigrastatic Effects of Oroxylum indicum (L.) Kurz Extract on Breast Cancer Cell

Breast cancer recurrence continues to pose a major clinical problem, despite significant advancements in early diagnosis and an aggressive mode of treatment. This study aimed at investigating the anticancer activity of Oroxylum indicum extract (OIE) by assessing cell proliferation, cell migration, and angiogenesis in metastatic breast cancer MDA-MB-231 cell lines. This study also estimated the phytochemical profiles of OIE by LC-QTOF-MS. The extract was found to contain six identified flavonoid substances, and baicalein was the most abundant substance in the extract. Cell proliferation capacity was performed by cell counting kit-8 (CCK-8) and colony formation assays. The effect of OIE on cell migration was determined using wound healing and transwell assays. Meanwhile, MDA-MB-231-induced angiogenesis on chick chorioallantoic membrane (CAM) was applied to investigate the ex vivo antiangiogenesis activity of the extracts. OIE at concentrations lower than 600 μg/mL had no cytotoxic effects against MDA-MB-231 cells. OIE was found to inhibit the long-term colony formation ability of MDA-MB-231 cells in a concentration-dependent manner. Antimigration and antiangiogenesis activities were further investigated using noncytotoxic concentrations of OIE ranging from 25 to 150 μg/mL. OIE greatly reduced the migration of MDA-MB-231 breast cancer cells in a dose-dependent manner. OIE significantly suppressed the MDA-MB-231-induced angiogenesis, and there was no substantial toxic effect on natural angiogenesis. Interestingly, the concentration of OIE at 150 μg/mL was as practically potent as pazopanib, the positive anticancer drug, at 4.37 μg/mL in inhibiting MDA-MB-231 cell migration and angiogenesis induced by these cells. Therefore, the inhibitory effects of OIE in cell proliferation and cell migration, together with antiangiogenesis in MDA-MB-231 breast cancer cells, suggesting that OIE has the potential to be a novel adjunct candidate for breast cancer chemotherapeutic agents.

Unraveling the Role of Scutellaria baicalensis for the Treatment of Breast Cancer Using Network Pharmacology, Molecular Docking, and Molecular Dynamics Simulation

Scutellaria baicalensis is often used to treat breast cancer, but the molecular mechanism behind the action is unclear. In this study, network pharmacology, molecular docking, and molecular dynamics simulation are combined to reveal the most active compound in Scutellaria baicalensis and to explore the interaction between the compound molecule and the target protein in the treatment of breast cancer. In total, 25 active compounds and 91 targets were screened out, mainly enriched in lipids in atherosclerosis, the AGE-RAGE signal pathway of diabetes complications, human cytomegalovirus infection, Kaposi-sarcoma-associated herpesvirus infection, the IL-17 signaling pathway, small-cell lung cancer, measles, proteoglycans in cancer, human immunodeficiency virus 1 infection, and hepatitis B. Molecular docking shows that the two most active compounds, i.e., stigmasterol and coptisine, could bind well to the target AKT1. According to the MD simulations, the coptisine-AKT1 complex shows higher conformational stability and lower interaction energy than the stigmasterol-AKT1 complex. On the one hand, our study demonstrates that Scutellaria baicalensis has the characteristics of multicomponent and multitarget synergistic effects in the treatment of breast cancer. On the other hand, we suggest that the best effective compound is coptisine targeting AKT1, which can provide a theoretical basis for the further study of the drug-like active compounds and offer molecular mechanisms behind their roles in the treatment of breast cancer.

Melanoma Cellular Signaling Transduction Pathways Targeted by Polyphenols Action Mechanisms

Melanoma is the most aggressive type of skin cancer. Although different anti-melanoma treatments are available, their efficacy is still improvable, and the number of deaths continues to increase worldwide. A promising source of antitumor agents could be presented by polyphenols-natural plant-based compounds. Over the past decades, many studies have described multiple anticancer effects of polyphenols in melanoma, presenting their potential interactions with targeted molecules from different signaling pathways. However, to our knowledge, there is no comprehensive review on polyphenols-regulated mechanisms in melanoma cells available in the literature. To fulfill this gap, this article aims to summarize the current knowledge of molecular mechanisms of action regulated by polyphenols involved in melanoma initiation and progression. Here, we focus on in vitro and in vivo effects of polyphenol treatments on tumor-essential cellular pathways, such as cell proliferation, apoptosis, autophagy, inflammation, angiogenesis, and metastasis. Moreover, emerging studies regarding the well-marked role of polyphenols in the regulation of microRNAs (miRNAs), highlighting their contribution to melanoma development, are also epitomized. Finally, we hope this review will provide a firm basis for developing polyphenol-based therapeutic agents in melanoma treatment.

The Multifaceted Role of Baicalein in Cancer Management through Modulation of Cell Signalling Pathways

The roles of medicinal plants or their purified bioactive compounds have attracted attention in the field of health sciences due to their low toxicity and minimal side effects. Baicalein is an active polyphenolic compound, isolated from Scutellaria baicalensis, and plays a significant role in the management of different diseases. Epidemiologic studies have proven that there is an inverse association between baicalein consumption and disease severity. Baicalein is known to display anticancer activity through the inhibition of inflammation and cell proliferation. Additionally, the anticancer potential of baicalein is chiefly mediated through the modulation of various cell-signaling pathways, such as the induction of apoptosis, autophagy, cell cycle arrest, inhibition of angiogenesis, signal transducer and activator of transcription 3, and PI3K/Akt pathways, as well as the regulation of other molecular targets. Therefore, the current review aimed to explore the role of baicalein in different types of cancer along with mechanisms of action. Besides this, the synergistic effects with other anti-cancerous drugs and the nano-formulation based delivery of baicalein have also been discussed.

Flavonoids as regulators of TIMPs expression in cancer: Consequences, opportunities, and challenges

Cancer is one of the leading causes of death in patients worldwide, where invasion and metastasis are directly responsible for this statement. Although cancer therapy has progressed in recent years, current therapeutic approaches are ineffective due to toxicity and chemoresistance. Therefore, it is essential to evaluate other treatment options, and natural products are a promising alternative as they show antitumor properties in different study models. This review describes the regulation of tissue inhibitors of metalloproteinases (TIMPs) expression and the role of flavonoids as molecules with the antitumor activity that targets TIMPs therapeutically. These inhibitors regulate tissue extracellular matrix (ECM) turnover; they inhibit matrix metalloproteinases (MMPs), cell migration, invasion, and angiogenesis and induce apoptosis in tumor cells. Data obtained in cell lines and in vivo models suggest that flavonoids are chemopreventive and cytotoxic against various types of cancer through several mechanisms. Flavonoids also regulate crucial signaling pathways such as focal adhesion kinase (FAK), phosphatidylinositol-3-kinase (PI3K)-Akt, signal transducer and activator of transcription 3 (STAT3), nuclear factor κB (NFκB), and mitogen-activated protein kinase (MAPK) involved in cancer cell migration, invasion, and metastasis. All these data reposition flavonoids as excellent candidates for use in cancer therapy.

Investigation of the mechanism of the anti-cancer effects of Astragalus propinquus Schischkin and Pinellia pedatisecta Schott (A&P) on melanoma via network pharmacology and experimental verification

Melanoma is a commonly malignant cutaneous tumor in China. Astragalus propinquus Schischkin and Pinellia pedatisecta Schott (A&P) have been clinically used as adjunctive drugs in the treatment of malignant melanoma. However, the effect and mechanism of A&P on melanoma have yet to be explored. The current investigation seeks to characterize the active components of A&P and their potential roles in treating malignant melanoma using network pharmacology and in vitro and in vivo experiments. We first used the traditional Chinese medicine systems pharmacology (TCMSP) database and high-performance liquid chromatography-mass spectrometry (HPLC-MS/MS) to identify a total of 13 effective compounds within A&P. 70 common genes were obtained by matching 487 potential genes of A&P with 464 melanoma-related genes, and then we built up protein-protein interaction (PPI) network of these 70 genes, followed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. The results revealed that A&P might influence the pathobiology of melanoma through the PI3K/Akt pathway. Molecular docking also confirmed that higher content of ingredients in A&P, including hederagenin, quercetin, beta-sitosterol and stigmasterol, had a strong binding activity (affinity < −5 kcal/mol) with the core targets AKT1, MAPK3 and ESR1. Furthermore, we confirmed A&P could inhibit melanoma cells proliferation and induce cells apoptosis through suppressing the PI3K/Akt signaling pathway by in vitro and in vivo xenograft model experiments. These findings indicate that A&P may function as a useful therapy for melanoma through the PI3K/Akt pathway.

Regulation of Cell Signaling Pathways and Non-Coding RNAs by Baicalein in Different Cancers

Landmark discoveries in molecular oncology have provided a wide-angle overview of the heterogenous and therapeutically challenging nature of cancer. The power of modern ‘omics’ technologies has enabled researchers to deeply and comprehensively characterize molecular mechanisms underlying cellular functions. Interestingly, high-throughput technologies have opened new horizons for the design and scientific fool-proof evaluation of the pharmacological properties of targeted chemical compounds to tactfully control the activities of the oncogenic protein networks. Groundbreaking discoveries have galvanized the expansion of the repertoire of available pharmacopoeia to therapeutically target a myriad of deregulated oncogenic pathways. Natural product research has undergone substantial broadening, and many of the drugs which constitute the backbone of modern pharmaceuticals have been derived from the natural cornucopia. Baicalein has gradually gained attention because of its unique ability to target different oncogenic signal transduction cascades in various cancers. We have partitioned this review into different sub-sections to provide a broader snapshot of the oncogenic pathways regulated by baicalein. In this review, we summarize baicalein-mediated targeting of WNT/β-catenin, AKT/mTOR, JAK/STAT, MAPK, and NOTCH pathways. We also critically analyze how baicalein regulates non-coding RNAs (microRNAs and long non-coding RNAs) in different cancers. Finally, we conceptually interpret baicalein-mediated inhibition of primary and secondary growths in xenografted mice.

Tepotinib suppresses proliferation, invasion, migration, and promotes apoptosis of melanoma cells via inhibiting MET and PI3K/AKT signaling pathways

Malignant melanoma seriously threatens public health and lowers the quality of life of the affected subjects. The present study was designed to explore the effects of tepotinib, a selective tyrosine kinase inhibitor of MET proto-oncogene, receptor tyrosine kinase (MET), on the progression of melanoma. Firstly, MTT assays were used to detect the proliferation of tepotinib-treated WM451 cells. The cell invasive and migratory activities were assessed using Transwell and wound healing assays, respectively. In addition, TUNEL staining was employed to determine cell apoptosis. Western blot analysis was utilized for the evaluation of the expression levels of apoptotic and epithelial-mesenchymal transition-related proteins, as well as of proteins involved in the PI3K/AKT signaling pathway. Subsequently, hepatocyte growth factor (HGF), a natural agonist of MET, was administered to WM451 cells to unravel the detailed mechanism of action of tepotinib in melanoma. The results indicated that the proliferation of WM451 cells was significantly decreased by tepotinib treatment. The inhibitory effects of tepotinib on the proliferation of WM451 cells occurred in a concentration-dependent manner. In addition, the migratory and invasive activities of WM451 cells were significantly suppressed following tepotinib treatment. It was also shown that tepotinib exhibited promotive effects on the induction of apoptosis of WM451 cells. Moreover, activation of MET and PI3K/AKT signaling pathways may be blocked by tepotinib treatment, whereas addition of HGF to the cells reversed the effects of tepotinib treatment on the malignant progression of WM451 cells. In conclusion, the data demonstrated that tepotinib suppressed the proliferation, invasion and migration of melanoma cells, whereas it could also induce their apoptosis. This evidence may provide a new perspective for the improvement of malignant melanoma.

Baicalein Inhibits Metastatic Phenotypes in Nasopharyngeal Carcinoma Cells via a Focal Adhesion Protein Integrin β8

Baicalein, a prominent flavonoid from the indigenous herbal plant Scutellaria baicalensis Georgi, possesses broad-spectrum anticancer activities. However, the biological effects of baicalein on nasopharyngeal carcinoma (NPC) and its underlying mechanisms remain unclarified. Thus, in this study, we examined the effects of baicalein on NPC cell lines and investigated the corresponding molecular mechanism through transcriptome profiling. In the study, four NPC cell lines were treated with various concentrations of baicalein at different time points. Cellular toxicity and proliferative inhibition of baicalein were examined by MTT assay. Metastatic phenotypes of NPC cells were investigated by wound healing, transwell, and adhesion assays. Additionally, microarray experiments were performed to determine the cellular pathways affected by baicalein. The expression and localization of the integrin β8 were validated by western immunoblotting and immunofluorescence. Our results revealed that baicalein exhibited its cytotoxicity and antiproliferative activity on all tested NPC cell lines. It also significantly inhibited metastatic phenotypes at sub-lethal concentrations. Transcriptomic analysis showed that baicalein significantly affected the focal adhesion pathway in NPC, where integrin β8 was greatly diminished. Thus, the present study results suggested that baicalein inhibits the metastatic phenotypes of NPC cells by modulating integrin β8, one of the major molecules in a focal adhesion pathway.

The Research on the Treatment of Metastatic Skin Cutaneous Melanoma by Huanglian Jiedu Decoction Based on the Analysis of Immune Infiltration Analysis

Objective

To explore the potential mechanism of Huanglian Jiedu Decoction (HJD) treatment and prevention of metastatic Cutaneous Melanoma (CM) occurrence and metastasis based on network pharmacological methods and immune infiltration analysis.

Methods

The GEO database was used to obtain metastatic CM disease targets, the TCMSP database and the HERB database were used to obtain HJD action targets, core genes were screened by protein interaction network, and the potential mechanism of HJD in the treatment of metastatic CM was explored by enrichment analysis, prognostic analysis and immune infiltration analysis.

Results

HJD treatment of metastatic CM involved 60 targets, enrichment analysis showed that HJD treatment of metastatic CM involved Chemokine signaling pathway, NF-kappa B signaling pathway, and Fluid shear stress and atherosclerosis, etc. Prognostic analysis revealed that HJD had a certain ability to improve the prognosis of metastatic CM patients. Immune infiltration analysis showed that HJD could inhibit the immune cell infiltration of metastatic CM patients by acting on related targets.

Conclusions

Our study identified the potential mechanism of HJD in the treatment of metastatic CM through network pharmacology, and revealed the mechanism of HJD in the prevention of Skin Cutaneous Melanoma metastasis through immune infiltration analysis and prognostic analysis.

In Vitro Effects of Selective COX and LOX Inhibitors and Their Combinations with Antineoplastic Drugs in the Mouse Melanoma Cell Line B16F10

The constitutive expression or overactivation of cyclooxygenase (COX) and lipoxygenase (LOX) enzymes results in aberrant metabolism of arachidonic acid and poor prognosis in melanoma. Our aim is to compare the in vitro effects of selective COX-1 (acetylsalicylic acid), COX-2 (meloxicam), 5-LOX (MK-886 and AA-861), 12-LOX (baicalein) and 15-LOX (PD-146176) inhibition in terms of proliferation (SRB assay), mitochondrial viability (MTT assay), caspase 3-7 activity (chemiluminescent assay), 2D antimigratory (scratch assay) and synthesis of eicosanoids (EIA) in the B16F10 cell line (single treatments). We also explore their combinatorial pharmacological space with dacarbazine and temozolomide (median effect method). Overall, our results with single treatments show a superior cytotoxic efficacy of selective LOX inhibitors over selective COX inhibitors against B16F10 cells. PD-146176 caused the strongest antiproliferation effect which was accompanied by cell cycle arrest in G₁ phase and an >50-fold increase in caspases 3/7 activity. When the selected inhibitors are combined with the antineoplastic drugs, only meloxicam provides clear synergy, with LOX inhibitors mostly antagonizing. These apparent contradictions between single and combination treatments, together with some paradoxical effects observed in the biosynthesis of eicosanoids after FLAP inhibition in short term incubations, warrant further mechanistical in vitro and in vivo scrutiny.

Anti-proliferative and pro-apoptotic activity of glycosidic derivatives of lawsone in melanoma cancer cell

Background

Melanoma is a malignant cancer that affects melanocytes and is considered the most aggressive skin-type cancer. The prevalence for melanoma cancer for the last five year is about one million cases. The impact caused of this and other types of cancer, revel the importance of research into potential active compounds. The natural products are an important source of compounds with biological activity and research with natural products may enable the discovery of compounds with potential activity in tumor cells.

Methods

The Sulforhodamine B was used to determine cell density after treatment with lawsone derivatives. Apoptosis and necrosis were analyzed by flow cytometer. Morphological changes were observed by fluorescence using the Phalloidin/FITC and DAPI stains. The clonogenic and wound healing assays were used to analyze reduction of colonies formation and migratory capacity of melanoma cells, respectability.

Results

In pharmacological screening, seven compounds derived from lawsone were considered to have high cytotoxic activity (GI > 75%). Three compounds were selected to assess the inhibitory concentration for 50% of cells (IC₅₀), and the compound 9, that has IC₅₀ 5.3 μM in melanoma cells, was selected for further analyses in this cell line. The clonogenic assay showed that the compound is capable of reducing the formation of melanoma colonies at 10.6 μM concentration. The compound induced apoptotic morphological changes in melanoma cells and increased by 50% the cells dying from apoptosis. Also, this compound reduced the migratory capacity of melanoma cells.

Conclusions

The results of this study showed that the evaluated lawsone derivatives have potential activity on tumor cells. The compound 9 is capable of inducing cell death by apoptosis in melanoma cells (B16F10).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08404-4.

Baicalein inhibits FURIN-MT1-MMP-mediated invasion of ectopic endometrial stromal cells in endometriosis possibly by reducing the secretion of TGFB1

PROBLEM

Endometriosis (EMs) is characterized by the presence of endometrial stroma and glands outside the uterus. Our previous study showed that baicalein inhibited proliferation and induced apoptosis in EMs. However, the effects of baicalein on the invasiveness of ectopic endometrial stromal cells (EcESCs) remain unclear. The aim of this study was to assess the potential anti-invasive effect of baicalein and determine the underlying mechanism.

METHODS

The invasive and migratory properties of EcESCs were assessed in vitro using Transwell and wound healing assays. The expression of functional markers of EcESCs, including matrix metalloproteases (MMPs), FURIN, and TGFB1, was analyzed using WB and ELISA. Additionally, a mouse model of EMs was treated with baicalein (10 mg/kg/d and 35 mg/kg/d) for 4 weeks. The weight and number of ectopic lesions were determined, and the expression of markers was assessed using immunohistochemistry.

RESULTS

Baicalein inhibited the invasion of EcESCs and the expression of certain invasion-related proteins, including MMP9, MMP2, and MT1-MMP. Exposure to baicalein reduced the extracellular levels of TGFB1 in EcESCs and the reduced expression of TGFB1, resulting in decreased expression of FURIN in EcESCs, which serves a pivotal role in the transformation of pro-MT1-MMP to activated MT1-MMP. In the mouse model of EMs, intraperitoneal injection of baicalein inhibited the growth of ectopic lesions and reduced MT1-MMP, FURIN, and TGFB1 expression.

CONCLUSIONS

Baicalein reduced the invasion of EMs, potentially by restricting the FURIN-MT1-MMP-mediated cell invasion of EcESCs maybe through reduction of the autocrine of TGFB1.

Targeting PI3K/Akt/mTOR signaling pathway by polyphenols: Implication for cancer therapy

Cancer is one of the biggest challenges facing medicine and its cure is regarded to be the Holy Grail of medicine. Therapy in cancer is consisted as various artificial cytotoxic agents and radiotherapy, and recently immunotherapy. Recently much attention has been directed to the use of natural occurring agents in cancer therapy. One of the main group of agents utilized in this regard is polyphenols which are found abundantly in berries, fruits and vegetables. Polyphenols show to exert direct and indirect effects in progression of cancer, angiogenesis, proliferation and enhancing resistance to treatment. One of the cellular pathways commonly affected by polyphenols is PI3K/Akt/mTOR pathway, which has far ranging effects on multiple key aspects of cellular growth, metabolism and death. In this review article, evidence regarding the biology of polyphenols in cancer via PI3K/Akt/mTOR pathway is discussed and their application on cancer pathophysiology in various types of human malignancies is shown.

Baicalein restrains proliferation, migration, and invasion of human malignant melanoma cells by down-regulating colon cancer associated transcript-1

Baicalein (BAI) is an acknowledged flavonoids compound, which is regarded as a useful therapeutic pharmaceutical for numerous cancers. However, its involvement in melanoma is largely unknown. This study aimed to examine the anti-melanoma function of BAI and unraveled the regulatory mechanism involved. A375 and SK-MEL-28 were treated with BAI for 24 h. Then, CCK-8 assay, flow cytometry, and transwell assay were carried out to investigate cell growth, migration, and invasion. RT-qPCR was applied to detect the expression of colon cancer associated transcript-1 (CCAT1) in melanoma tissues and cells. The functions of CCAT1 in melanoma cells were also evaluated. Western blot was utilized to appraise Wnt/β-catenin or MEK/ERK pathways. BAI restrained cell proliferation and stimulated cell apoptotic capability of melanoma by suppressing cleaved-caspase-3 and cleaved-PARP. Cell migratory and invasive abilities were restrained by BAI via inhibiting MMP-2 and vimentin. CCAT1 was over-expressed in melanoma tissues and down-regulated by BAI in melanoma cells. Overexpressed CCAT1 reversed the BAI-induced anti-growth, anti-migratory, and anti-invasive effects. Furthermore, BAI inhibited Wnt/β-catenin and MEK/ERK pathways-axis via regulating CCAT1. Our study indicated that BAI blocked Wnt/β-catenin and MEK/ERK pathways via regulating CCAT1, thereby inhibiting melanoma cell proliferation, migration, and invasion.

Citrus unshiu peel suppress the metastatic potential of murine melanoma B16F10 cells in vitro and in vivo

The peel of Citrus unshiu Marcow. fruits (CU) has long been used as a traditional medicine that has therapeutic effects against pathogenic diseases, including asthma, vomiting, dyspepsia, blood circulation disorders, and various types of cancer. In this study, we investigated the effect of CU peel on metastatic melanoma, a highly aggressive skin cancer, in B16F10 melanoma cells, and in B16F10 cells inoculated‐C57BL/6 mice. Our results show that ethanol extracts of CU (EECU) inhibited cell growth and increased the apoptotic cells in B16F10 cells. EECU also stimulated the induction of mitochondria‐mediated intrinsic pathway, with reduced mitochondrial membrane potential and increased generation of intracellular reactive oxygen species. Furthermore, EECU suppressed the migration, invasion, and colony formation of B16F10 cells. In addition, the oral administration of EECU reduced serum lactate dehydrogenase activity without weight loss, hepatotoxicity, nor nephrotoxicity in B16F10 cell‐inoculated mice. Moreover, EECU markedly suppressed lung hypertrophy, the number and expression of metastatic tumor nodules, and the expression of inflammatory tumor necrosis factor‐alpha in lung tissue. In conclusion, our findings suggest that the inhibitory effect of EECU on the metastasis of melanoma indicates that it may be regarded as a potential therapeutic herbal drug for melanoma.

Anticancer Effects of Baicalein in FRO Thyroid Cancer Cells Through the Up-regulation of ERK/p38 MAPK and Akt Pathway

BACKGROUND/AIM

The aim of the study was to evaluate the anticancer effects of baicalein in FRO anaplastic thyroid cancer (ATC) cells.

MATERIALS AND METHODS

FRO cells were treated with baicalein and viability was measured by the MTT assay. Cell apoptosis was observed by staining with Hoechst dye. The expression of apoptotic proteins (Bax, Bcl-2, PARP, cytochrome c, and caspase-3) and the inflammatory protein Cox-2 and the phosphorylation of MAPKs and Akt were determined by western blot.

RESULTS

Treatment with baicalein inhibited cell proliferation in a time-dependent manner and increased DNA fragmentation and apoptosis in FRO cells. Baicalein at 50 and 100 μM inhibited the expression of Bax, PARP, cytochrome c, cleaved caspase-3, and Cox-2, and increased the expression of Bcl-2. Baicalein increased the phosphorylation of ERK, p38 MAPK, and Akt and decreased JNK phosphorylation.

CONCLUSION

Baicalein caused anticancer effects in FRO ATC cells through induction of apoptosis and regulation of the MAPK and Akt pathway.

miR-188-5p regulates proliferation and invasion via PI3K/Akt/MMP-2/9 signaling in keloids

Keloids (KDs) and hypertrophic scars (HSs), two forms of pathological scars, seriously affect the physical and psychological health of patients. Despite many similarities with HSs, KDs are characterized by invasion and a high rate of recurrence after surgery, features they share in common with tumors. The underlying molecular mechanisms of this phenomenon have not been fully elucidated. In this study, we used microRNA (miRNA) array analysis to search for invasion-associated miRNAs in KDs. The expression of miR-188-5p in KDs, HSs, normal skin (NS) tissues, and cell lines was measured by quantitative real-time polymerase chain reaction. Furthermore, cell proliferation, migration, and invasion were detected in KD fibroblasts (KFs) and HS fibroblasts (HSFs), and interrelated proteins were ascertained by western blot analysis. It was found that miR-188-5p was significantly decreased in KD tissue compared with HS and NS tissues. Upregulated expression of miR-188-5p suppressed KF proliferation, migration, and invasion; and decreased expression of miR-188-5p also promoted HSF proliferation, migration, and invasion. The protein levels of MMP-2, MMP-9, PI3K, and p-Akt in miR-188-5p mimic-transfected KFs were repressed. In contrast, after transfection with miR-188-5p inhibitor, the protein levels of MMP-2, MMP-9, PI3K, and p-Akt were higher than the control in HSFs. Treatment with PI3K/Akt inhibitor LY294002 in KFs with miR-188-5p inhibitor did not further reduce their proliferation, migration, and invasion. The upregulation of MMP-2 and MMP-9 by miR-188-5p inhibitor could be abolished by LY294002. These findings together demonstrate a tumor-suppressive role of miR-188-5p in KD proliferation and invasion via PI3K/Akt/MMP-2/9 signaling, indicating that miR-188-5p may be a potential prognostic marker and therapeutic target for KDs.

Protective Effect of Baicalein on Oxidative Stress-induced DNA Damage and Apoptosis in RT4-D6P2T Schwann Cells

Background: Due to its high antioxidant activity, baicalein, a kind of flavonoid present in Radical Scutellariae, has various pharmacological effects. However, the protective effect against oxidative stress in Schwann cells, which plays an important role in peripheral neuropathy, has not yet been studied. In this study, the effects of baicalein on hydrogen peroxide (H₂O₂)-induced DNA damage and apoptosis in RT4-D6P2T Schwann cells were evaluated. Methods: Cell viability assay was performed using MTT assay and colony formation assay. Apoptosis was assessed by flow cytometry analysis and DNA fragmentation assay. The effects on DNA damage and ATP content were analyzed by comet method and luminometer. In addition, changes in protein expression were observed by Western blotting. Results: Our results show that baicalein significantly inhibits H₂O₂-induced cytotoxicity through blocking reactive oxygen species (ROS) generation. We also demonstrate that baicalein is to block H₂O₂-induced DNA damage as evidenced by inhibition of DNA tail formation and γH2AX phosphorylation. Moreover, baicalein significantly attenuated H₂O₂-induced apoptosis and mitochondrial dysfunction, and restored inhibition of ATP production. The suppression of apoptosis by baicalein in H₂O₂-stimulated cells was associated with reduction of increased Bax/Bcl-2 ratio, activation of caspase-9 and -3, and degradation of poly (ADP-ribose) polymerase. Conclusions: These results demonstrate that baicalein eliminates H₂O₂-induced apoptosis through conservation of mitochondrial function by the removal of ROS. Therefore, it is suggested that baicalein protects Schwann cells from oxidative stress, and may be beneficial for the prevention and treatment of peripheral neuropathy induced by oxidative stress.

Steered migration and changed morphology of human astrocytes by an applied electric field

Direct current electric field (DC EF) plays a role in influencing the biological behaviors and functions of cells. We hypothesize that human astrocytes (HAs) could also be influenced in EF. Astrocytes, an important type of nerve cells with a high proportion quantitatively, are generally activated and largely decide the brain repair results after brain injury. So far, no electrotaxis study on HAs has been performed. We here obtained HAs derived from brain trauma patients. After purification and identification, HAs were seeded in the EF chamber and recorded in a time-lapse image system. LY294002 and U0126 were then used to probe the role of PI3K or ERK signaling pathway on cellular behaviors. The results showed that HAs could be guided to migrate to the anode in DC EFs, in a voltage-dependent manner. The HAs displayed elongated cell bodies and reoriented perpendicularly to the EF in morphology. When treated with LY294002 or U0126, alternation of parameters such as cellular verticality, track speed, displacement speed, long axis, vertical length and circularity were inhibited partly as expected, while the EF-induced directedness was not terminated even at a high drug dosage which was not consistent with previous electrotaxis studies. In conclusion, applied EFs steered the patient-derived HAs directional migration and changed morphology, in which PI3K and ERK pathways at least partially participate. The characteristics of HAs to EF stimulation may be involved in wound healing and neural regeneration, which could be utilized as a novel treatment strategy in brain injury.

Lycorine inhibits melanoma A375 cell growth and metastasis through the inactivation of the PI3K/AKT signaling pathway

Malignant melanoma, one of the most aggressive skin cancers, has a very high mortality rate. Currently, the number of drugs to treat melanoma is low. Although new immunotherapeutic approaches based on the use of antibodies against immune checkpoints have shown long term responses, it is urgent to develop novel anti-melanoma drugs with a high efficiency and a low toxicity in a large number of patients. Lycorine, a natural product, has been reported to exert antitumor effects on some cancers. However, the impact of lycorine on melanoma cells is still unknown. Using the CCK8 assay, we found that lycorine can suppress the proliferation of melanoma A375 cells in a dose-time-dependent manner. Moreover, a transwell assay showed that lycorine inhibited the migration and invasion of A375 cells significantly. Further, lycorine treatment could induce the apoptosis of the A375 cells. Biochemical analyses showed that the expression level of the anti-apoptosis Bcl-2 protein decreased, while the expression of the pro-apoptosis protein Bax and active caspase-3 increased after lycorine treatment. Finally, using western blot assay, we found that the antitumor effects of lycorine on A375 cells might be through the inactivation of the PI3K/Akt signaling pathway. Based on these observations, we suggest that lycorine may be an interesting candidate for further studies on its ability to represent a novel antitumor drug for human melanoma treatment in the future.

Baicalein suppresses non small cell lung cancer cell proliferation, invasion and Notch signaling pathway

BACKGROUND

Baicalein is an important Chinese herbal medicine and has multiple pharmacological activities. However, the biological mechanisms of the anti-tumor effects of Baicalein on non small cell lung cancer (NSCLC) still need to be understood.

METHODS

Human NSCLC A549 and H1299 cells were pretreated with Baicalein or DMSO. Cells viability and transwell cell invasion assays were performed to assess cell proliferation and invasion. QRT-PCR assay was used to analyze mRNA expression levels of Twist1, E-cadhertin, Vimentin, Notch1 and hes-1. Western blot analysis was also performed to determine protein expression.

RESULTS

In the study, we found that Baicalein had a significantly inhibited effect on proliferation ability of A549 and H1299 cells. Cells treated with Baicalein showed a down-regulated expression of CyclinD1 and CDK1 in A549 and H1299 cells. Furthermore, we found that Baicalein significantly inhibited cell invasion and Epithelial-Mesenchymal Transition (EMT) by up-regulating the mRNA and protein expression of E-cadherin and down-regulated the Twist1 and Vimentin expression, Moreover, Treatment of Baicalein down-regulated Notch1 and hes-1 expression in A549 and H1299 cells, which indicated that Baicalein could suppress the Notch signaling pathway.

CONCLUSION

Our studies suggest that Baicalein may be a potential phytochemical flavonoid for therapeutics of NSCLC and serve as a molecular target for NSCLC.

Matrix metalloproteinase 2/9-triggered-release micelles for inhaled drug delivery to treat lung cancer: preparation and in vitro/in vivo studies

Background

Improvement in drug accumulation in the lungs through inhalation administration and high expression of MMP2 and MMP9 in lung tumors have both been widely reported.

Methods

MMP2/9-triggered-release micelles were constructed and in vitro and in vivo studies of inhalation administration against lung tumor carried out. Pluronic P123 (P123) was modified with GPLGIAGQ-NH2 (GQ8) peptide to obtain P123-GQ8 (PG). MMP2/9-triggered-release micelles were constructed using PG and succinylated gelatin (SG) and loading paclitaxel (Ptx). To study biodistribution of micelles, DiR encapsulated in micelles was dosed to rats via intravenous injection or inhalation before ex vivo imaging for detecting DiR quantity in lungs. And B16F10 lung cancer-bearing nude mice were chosen as animal models to evaluate in vivo efficacy of MMP2/9-triggered-release micelles.

Results

Ptx-release efficiency from PG-SG-Ptx micelles was MMP2/9-concentration-dependent. For A549 cells, PG-SG-Ptx cytotoxicity was significantly greater (P<0.001) compared to P123-Ptx. Aerosol inhalation was chosen as the method of administration. In biodistribution experiment, DiR quantity in lungs was 5.8%±0.4% of that in major organs, while the ratio was 38.8%±0.5% for inhalation. For B16F10 lung cancer-bearing nude mice, the efficacy of inhalation of PG-SG-Ptx was significantly higher (P<0.001) than Taxol inhalation and injected PG-SG-Ptx. Inhaled PG-SG-Ptx also significantly inhibited the expression of Pgp in lung cancer.

Conclusion

Inhalation of MMP2/9-triggered-release micelles increased tumor sensitivity to chemotherapeutics and reduced the toxicity of chemotherapy to healthy lung cells, which has great potential in lung cancer therapy.

Scutellaria: Debates on the anticancer property

The widespread use of plants as accessible anticancer agents leads to the identification of many natural source chemotherapeutic agents. Scutellaria one of the popular genus of flowering plants has been used for various human illnesses for thousands of years. Scutellaria has anti-metastatic, anti-proliferative, anti-invasion, anti-angiogenic and apoptosis effects in vitro as well as in vivo. Despite numerous reports on the cytotoxic-antitumor activity of the plant, there are still some issues need further consideration. Issues such as unjustified interpretations, lack of attention to the pharmacokinetics profile and weak study design may affect the final decision about the use of plants as anticancer agents and possibly needs reconsideration. In this review, we have summarized the potential health benefits of Scutellaria and its active components also the underlying mechanism of cytotoxicity and antitumor activity. Meanwhile we have discussed concerns may interfere with the precise conclusion.

Liposome-Encapsulated Baicalein Suppressed Lipogenesis and Extracellular Matrix Formation in Hs68 Human Dermal Fibroblasts

The dermis of human skin contains large numbers of fibroblasts that are responsible for the production of the extracellular matrix (ECM) that supporting skin integrity, elasticity and wound healing. Previously, an in vivo study demonstrated that dermal fibroblasts siting in the lower dermis are capable to convert into skin adipose layer and hence fibroblast lipogenesis may vary the structure and elasticity of dermis. In the present study, Hs68 human dermal fibroblasts were utilized as an in vitro model to study the lipogenesis via using adipogenic differentiation medium (ADM). Baicalein, isolated from Scutellaria baicalensis, is one of the flavonoids to inhibit adipocyte differentiation due to high antioxidant activity in vitro. In order to develop a suitable formulation for baicalein (a poorly water-soluble drug), soybean phosphatidylcholine (SPC) was used to prepare baicalein-loaded liposomes to enhance drug bioavailability. Our results demonstrated that liposome-encapsulated baicalein protected cell viability and increased cellular uptake efficiency of Hs68 fibroblasts. Lipid accumulation, triglyceride synthesis and gene expressions of lipogenesis enzymes (FABP4 and LPL) were significantly increased in ADM-stimulated Hs68 fibroblasts but subsequently suppressed by liposome-encapsulated baicalein. In addition, ADM-induced TNF-α expression and related inflammatory factors was down-regulated by liposome-encapsulated baicalein. Through ADM-induced lipogenesis, the protein expression of elastin, type I and type III collagens increased remarkably, whereas liposome-encapsulated baicalein can down-regulate ADM-induced ECM protein synthesis. Taken together, we found that liposome-encapsulated baicalein can inhibit ADM-induced lipid accumulation and ECM formation in Hs68 fibroblasts through the suppression of lipogenesis enzymes and inflammatory responses. Liposome-encapsulated baicalein may have the potential to improve wound healing and restore skin structure after skin injury.

Effect of Baicalein on Matrix Metalloproteinases and Durability of Resin-Dentin Bonding

OBJECTIVE

In an attempt to increase resin-dentin bonding quality, this study used baicalein as a preconditioner in an etch-and-rinse adhesive to evaluate its effect on matrix metalloproteinases (MMPs) and adhesive durability.

METHODS

As a MMP inhibitor and potential collagen cross-linking agent, baicalein was used as a preconditioner in an etch-and-rinse adhesive system. The degree of conversion was evaluated by Fourier-transform infrared spectroscopy. EnzChek gelatinase/collagenase assay kits were then used to detect the MMP inhibitory effect of different concentrations of baicalein (0.1, 0.5, 2.5, and 5.0 μg/mL) on dentin powders. During in vitro bonding procedures, flat dentin surfaces on sound third molars were preconditioned with 2.5 μg/mL baicalein after being acid-etched; this step was followed by continuation of adhesive processes and build-up of resin composite. After resin-dentin stick preparation, bonding strength, failure mode, and interface nanoleakage were respectively evaluated via microtensile testing, stereomicroscopy, and field emission scanning electron microscopy either immediately or after storage in artificial saliva for three or six months. Data were analyzed by two-way analysis of variance and Tukey test (α=0.05).

RESULTS

Baicalein at a concentration of 0-5.0 μg/mL did not influence the conversion of adhesives. However, it inhibited the activities of dentin-bond gelatinase and collagenase, especially at a concentration of 2.5 μg/mL, while effectively increasing microtensile bonding strength and decreasing nanoleakage in vitro, both immediately and after aging.

CONCLUSIONS

Baicalein used as preconditioner in an etch-and-rinse adhesive system has an anti-MMP function and effectively improves resin-dentin bonding durability in vitro, which has potential value in clinical bonding procedures.

The axis IL-10/claudin-10 is implicated in the modulation of aggressiveness of melanoma cells by B-1 lymphocytes

B-1 lymphocytes are known to increase the metastatic potential of B16F10 melanoma cells via the extracellular signal-regulated kinase (ERK) pathway. Since IL-10 is associated with B-1 cells performance, we hypothesized that IL-10 could be implicated in the progression of melanoma. In the present work, we found that the C57BL/6 mice, inoculated with B16F10 cells that were co-cultivated with B-1 lymphocytes from IL-10 knockout mice, developed fewer metastatic nodules than the ones which were injected with the melanoma cells that were cultivated in the presence of wild-type B-1 cells. The impairment of metastatic potential of the B16F10 cells was correlated with low activation of the ERK signaling pathway, supporting the idea that the production of IL-10 by B-1 cells influences the behavior of the tumor. A microarray analysis of the B-1 lymphocytes revealed that IL-10 deficiency is associated with down-regulation of the genes that code for claudin-10, a protein that is involved in cell-to-cell contact and that has been linked to lung adenocarcinoma. In order to determine the impact of claudin-10 in the cross-talk between B-1 lymphocytes and the B16F10 tumor cells, we took advantage of small interfering RNA. The silencing of claudin-10 gene in B-1 lymphocytes inhibited activation of the ERK pathway and abrogated the B-1-induced aggressive behavior of the B16F10 cells. Thus, our findings suggest that the axis IL-10/claudin-10 is a promising target for the development of therapeutic agents against aggressive melanoma.

Matrix Metalloproteinases: A challenging paradigm of cancer management

Matrix metalloproteinases (MMPs) are members of zinc-dependent endopeptidases implicated in a variety of physiological and pathological processes. Over the decades, MMPs have been studied for their role in cancer progression, migration, and metastasis. As a result, accumulated evidence of MMPs incriminating role has made them an attractive therapeutic target. Early generations of broad-spectrum MMP inhibitors exhibited potent inhibitory activities, which subsequently led to clinical trials. Unexpectedly, these trials failed to meet the desired goals, mainly due to the lack of efficacy, poor oral bioavailability, and toxicity. In this review, we discuss the regulatory role of MMPs in cancer progression, current strategies in targeting MMPs for cancer treatment including prodrug design and tumor imaging, and therapeutic value of MMPs as biomarkers in breast, lung, and prostate cancers.

Nonimmobilized Biomaterial Capillary Electrophoresis for Screening Drugs Targeting Human Glucose Transporter 1

We report an online ligand screening method that targets human glucose transporter 1 (hGlut1) under approximately physiological conditions, named nonimmobilized biomaterial capillary electrophoresis (NIBCE), and we investigated the interactions between drugs/candidate compounds and HEK293 cells, hGlut1-overexpressing HEK293 cells, non-small-cell lung cancer A549 cells, A549 tumor tissue, and normal lung tissue by simulating the interactions between drugs and moving target cells or the space-occupying tumor. NIBCE omits the trouble of isolating and purifying target receptors from cell membrane while maintaining their native conformation and binding activity. The biomaterials were intercepted by porous frits in capillary columns and cannot flow through the detection window, thereby solving the problem of interference detection, and they can be renewed any time flexibly, thus effectively maintaining their surface bioactivity. Furthermore, the binding kinetic parameters (K, k_a, k_d, and k') were calculated by nonlinear chromatography (NLC) theory, and competitive binding experiments, ligand docking studies, and antitumor activity assays in vitro and in vivo were performed to verify the feasibility of NIBCE.

Investigation of dermal toxicity of ionic liquids in monolayer-cultured skin cells and 3D reconstructed human skin models

Ionic liquids have gained increasing attention in the chemical industry as potential green substitutes for traditional solvents. However, little is known about toxicity of ionic liquids on the skin, a major exposure portal to toxic substances. Here, we evaluated dermal toxicity of ionic liquids using human keratinocyte and fibroblast cell line, 3D reconstructed human epidermis, and full-thickness model to investigate underlying mechanisms. Cytotoxicity of ionic liquids was evaluated for representative anions, [TFSI], [PF₆], [BF₄], and [DCA], as well as for cations, [EMIM], [BMPY], [TBA] and [Zn], in human keratinocyte cell line, HaCaT, and human dermal fibroblasts. In our results, significant cytotoxicity was induced by ionic liquids with [TFSI] in both cell lines. Notably, cytotoxicity of [TFSI] containing ionic liquids was comparable to xylene, a toxic conventional organic solvent. Fluorescent and flow cytometric analysis revealed that [TFSI]-exposed cells underwent necrotic cell death. Reactive oxygen species (ROS) was increased while the amount of glutathione was decreased by [TFSI] in dose-dependent manner, which was reversed by antioxidant, N-acetylcysteine. In 3D reconstructed human epidermis and full-thickness model, a single application of [TFSI] induced toxicity although it was minimal and largely limited to epidermal layer. Collectively, these results demonstrated potential dermal toxicity of ionic liquids.

Scutellaria baicalensis Georgi induces caspase-dependent apoptosis via mitogen activated protein kinase activation and the generation of reactive oxygen species signaling pathways in MCF-7 breast cancer cells

Scutellaria baicalensis Georgi extract (SBGE) is used in traditional herbal medicine and has also been used clinically to ameliorate the symptoms of various inflammatory diseases and cancer. In women, breast cancer is one of the most common diseases and numerous women succumb to it. The present study was undertaken to investigate the mechanism responsible for the SBGE‑induced apoptosis of MCF‑7 human breast cancer cells. SBGE was administered to cells at concentrations between 100 and 500 mg/ml, and cell viabilities were identified using an MTT assay. B‑cell lymphoma 2 (Bcl-2) and Bcl-2 X‑associated protein (Bax) family members were identified by western blotting, and the mRNA expression levels of the pro‑apoptosis genes Fas, Fas ligand (FasL) and tumor necrosis factor (TNF)‑α were assessed by reverse transcription‑polymerase chain reaction. It was identified that SBGE treatment for 24 h inhibited MCF‑7 proliferation and increased the sub‑G1 phase ratio. SBGE suppressed mitochondrial membrane potentials and SBGE‑induced apoptotic cell death was identified to be associated with downregulation of Bcl‑2, but upregulation of Bax. SBGE‑activated caspases 3 and 9, and increased reactive oxygen species generation. However, SBGE had no effect on the expression levels of Fas, FasL or TNF‑α. Furthermore, mitogen‑activated protein kinase and C‑Jun N‑terminal kinase inhibitors inhibited SBGE‑induced cell death. These results suggested that SBGE be considered as an agent for the treatment of breast cancer.

Anti-melanogenic activity of phytosphingosine via the modulation of the microphthalmia-associated transcription factor signaling pathway

BACKGROUND

Microphthalmia-associated transcription factor (MITF) suppresses the expression of enzymes controlling the production of melanin. Phytosphingosine is a well-known cosmetic agent, but its anti-melanogenic activity and mechanism of action remain unclear.

OBJECTIVE

This study was designed to investigate the effects of phytosphingosine on melanin synthesis and elucidate the plausible mechanism of actions in vitro and ex vivo systems.

METHODS

Melanin content, cell viability, tyrosinase activity, p-CREB DNA binding activity, and the protein gene expression levels of the enzymes and proteins involved in melanogenesis were measured with the treatment of phytosphingosine.

RESULTS

Phytosphingosine inhibits melanin synthesis in cultured melan-a cells and a reconstructed human skin model. One possible mechanism of the anti-melanogenic activity of phytosphingosine appears to be associated with the modulation of MITF, which suppresses the expression of tyrosinase, tyrosinase-related protein-1 (TRP-1), and TRP-2. Further analysis revealed that phytosphingosine suppressed paired box 3 and SRY-related HMG-box 10, critical transcription factors of MITF. Phytosphingosine also effectively downregulated the protein levels of β-catenin and the phospho-cAMP response element binding protein, an upstream regulatory factor of MITF. These results are closely related to the suppression of MITF gene expression. In addition, treatment with phytosphingosine for over 12h, which is a relatively long period of time, did not directly suppress these MITF transcriptional factors. Instead, phytosphingosine induced ERK activation, which led to MITF phosphorylation, followed by its degradation. Therefore, the downregulation of MITF protein levels by phytosphingosine with a long time exposure is in part associated with MITF protein degradation through the MAPK kinase activation pathway.

CONCLUSION

The modulation of MITF by phytosphingosine is closely related with the signaling pathways, such as the suppression of the MITF gene expression and the degradation of the MITF protein, depending on the duration of treatment time. These results suggest that phytosphingosine might serve as an effective melanogenesis inhibitor in melanocytes via the regulation of the MITF signaling pathways.