Betulinic acid isolated from Vitis amurensis root inhibits 3-isobutyl-1-methylxanthine induced melanogenesis via the regulation of MEK/ERK and PI3K/Akt pathways in B16F10 cells

Research Progress on Application of Inonotus obliquus in Diabetic Kidney Disease

Diabetic kidney disease (DKD) is one of the prime causes of end-stage renal disease. At present, the treatment of DKD is mainly confined to inhibiting the renin-angiotensin-aldosterone system, but the therapeutic effects is not satisfactory. As a kind of very rare and precious medicinal fungi, Inonotus obliquus has a very high medicinal value. Due to its special hypoglycemic and pharmacological effect, researchers currently have attached great importance to it. In this paper, the biological activities, pharmacological effects and application status in the treatment of DKD-related diseases of Inonotus obliquus and the latest progress of metabolites isolated from it in DKD were summarized, thus providing detailed insights and basic understanding of the potential application prospects in DKD.

Structural Optimization of Cannabidiol as Multifunctional Cosmetic Raw Materials

Cannabidiol (CBD), derived from the plant cannabis, can be used in the cosmetics industry for its antioxidant, anti-inflammatory, anti-wrinkle and whitening effects. However, CBD is purified from the hemp plant extract, its source is very limited and under strict control. So in this study, computational and experimental methods were combined to search for novel CBD substitutes with high biology potencies. The action mode between CBD and target protein cannabidiol receptor 1 was studied to find the key skeleton, which was used to virtually screen a natural products database to search for compounds with 70% similarity. The hit compounds with high docking scores were selected for the ABTS and DPPH free radical scavenging experiments for antioxidant evaluation. The effects on the expressions of nitric oxide (NO), interleukin-6 (IL-6), COX-2 and iNOS in RAW264.7 cell line were detected to demonstrate their anti-inflammatory abilities. The effect of anti-wrinkle ability were evaluated by detecting the extracellular matrix, such as collagen, elastin, fibronectin and reactive oxygen species (ROS) in HFF-1. The effects on melanin production and tyrosinase activity in Bb16F10 were also detected. As a result, two compounds were found to be superior to cannabidiol, in terms of antioxidant, anti-wrinkle and whitening efficacy with a lower cytotoxicity.

Screening and Structure-Activity Relationship for Selective and Potent Anti-Melanogenesis Agents Derived from Species of Mulberry (Genus Morus)

Tyrosinase is a multifunctional, copper-containing and rate-limiting oxidase that catalyses crucial steps in the melanogenesis pathway and is responsible for skin-pigmentation abnormalities in mammals. Numerous tyrosinase inhibitors derived from natural and synthetic sources have been identified as an objective for the development of anti-melanogenesis agents. However, due to side effects and lack of expected efficiency, only a small percentage of them are used for medical and cosmetic purposes. This critical review focuses on searching for novel active substances and recently discovered plant-derived anti-tyrosinase inhibitors from the Morus genus (Moraceae family). A detailed analysis of their structure-activity relationships is discussed. The information contained in this article is crucial for the cosmetics and medical industries, in order to show new directions for the effective search for natural anti-melanogenesis products (with satisfactory efficiency and safety) to treat and cure hyperpigmentation.

Antimelanogenesis Effect of Methyl Gallate through the Regulation of PI3K/Akt and MEK/ERK in B16F10 Melanoma Cells

Methyl gallate is a polyphenolic compound found in many plants, and its antioxidant, antitumor, antibacterial, and anti-inflammatory effects have been extensively studied. More recently, antidepressant-like effects of methyl gallate have been demonstrated in some studies. In the present study, we examined the effects of methyl gallate on melanogenesis, including the tyrosinase inhibitory effect, the melanin content, and the molecular signaling pathways involved in this inhibition. The results showed that methyl gallate inhibited tyrosinase activity and significantly downregulated the expressions of melanin synthesis-associated proteins, including microphthalmia-associated transcription factor (MITF), tyrosinase, dopachrome tautomerase (Dct), and tyrosinase-related protein-1 (TRP1). In conclusion, our findings indicated that activation of MEK/ERK and PI3K/Akt promoted by methyl gallate caused downregulation of MITF and triggered its downstream signaling pathway, thereby inhibiting the production of melanin. In summary, methyl gallate showed significant inhibitory activity against melanin formation, implying that it may be a potential ingredient for application in skin-whitening cosmetics.

Nypa fruticans Wurmb inhibits melanogenesis in isobutylmethylxanthine‑treated melanoma via the PI3K/AKT/mTOR/CREB and MAPK signaling pathways

Malignant melanoma is responsible for 3.0 and 1.7% of cases of tumor incidence and tumor-associated mortality, respectively, in the Caucasian population. Melanoma is a type of skin cancer that occurs when melanocytes mutate and divide uncontrollably. Nypa fruticans Wurmb (NF) is abundant in phytochemicals (polyphenols and flavonoids) and is traditionally used to treat diseases of the respiratory tract. The present study investigated the inhibitory effect of the ethyl acetate fraction of NF (ENF) on melanogenesis-related factors in isobutylmethylxanthine-treated B16F10 melanoma cells. Phenolics and flavonoids (caffeic acid, catechin, epicatechin and hirsutine) in ENF were analyzed via liquid chromatography-mass spectrometry. In addition, the main factors involved in melanogenesis were identified using immunoblotting, reverse transcription-polymerase chain reaction (RT-PCR), RT-quantitative PCR and immunofluorescence. ENF significantly suppressed the expression of tyrosinase (TYR) and TYR-related proteins 1 and 2 (TYRP-1/2), which are the main factors involved in melanogenesis. ENF also inhibited the expression of microphthalmia-associated transcription factor (MITF) by phosphorylating the related cell signaling proteins (protein kinase B, mammalian target of rapamycin, phosphoinositide 3-kinase and cAMP response element-binding protein). Furthermore, ENF inhibited the phosphorylation of extracellular signal-regulated kinase and thereby downregulated melanogenesis. In conclusion, ENF inhibited melanogenesis by suppressing MITF, which controls TYRP-1/2 and TYR. These results suggested that ENF may be a natural resource that can inhibit excessive melanin expression by regulating various melanogenesis pathways.

A clickable photoaffinity probe of betulinic acid identifies tropomyosin as a target

Target identification of bioactive compounds is important for understanding their mechanisms of action and provides critical insights into their therapeutic utility. While it remains a challenge, unbiased chemoproteomics strategy using clickable photoaffinity probes is a useful and validated approach for target identification. One major limitation of this approach is the efficient synthesis of appropriately substituted clickable photoaffinity probes. Herein, we describe an efficient and consistent method to prepare such probes. We further employed this method to prepare a highly stereo-congested probe based on naturally occurring triterpenoid betulinic acid. With this photoaffinity probe, we identified tropomyosin as a novel target for betulinic acid that can account for the unique biological phenotype on cellular cytoskeleton induced by betulinic acid.

Promotion of the Differentiation of Dental Pulp Stem Cells into Oligodendrocytes by Knockdown of Heat-Shock Protein 27

Stem cell-based therapy has been evaluated in many different clinical trials for various diseases. This capability was applied in various neurodegenerative diseases, such as Alzheimer's disease, which is characterized by synaptic damage accompanied by neuronal loss. Dental pulp stem cells (DPSCs) are mesenchymal stem cells from the oral cavity and have been studied with potential application for regeneration of different tissues. Heat shock protein 27 (HSP27) is known to regulate neurogenesis in the process of neural differentiation of placenta-multipotent stem cells. Here, we hypothesize that HSP27 expression is also critical in neural differentiation of DPSCs. An evaluation of the possible role of HSP27 in differentiation of DPSCs was per-formed by gene knockdown and neural immunofluorescent staining. We found that HSP27 has a role in the differentiation of DPSCs and that knockdown of HSP27 in DPSCs renders cells to oligodendrocyte progenitors. In other words, shHSP27-DPSCs showed NG2-positive immunoreactivity and gave rise to oligodendrocytes or type-2 astrocytes. This neural differentiation of DPSCs may have clinical significance for treatment of patients with neurodegenerative diseases. In conclusion, our data provide an example of oligodendrocyte differentiation of a DPSCs model that may have potential application in human regenerative medicine.

Therapeutic Effect of Seawater Pearl Powder on UV-Induced Photoaging in Mouse Skin

The objective of this study was to investigate the therapeutic effect of seawater pearl powder (SPP) on ultraviolet (UV) irradiation-induced photoaging in mouse skin. The protein and trace elements in SPP were detected by liquid chromatography-mass spectrometry, atomic fluorescence spectrometry, and inductively coupled plasma-atomic emission spectrometry. The effect of SPP on treating skin damage resulting from UV-induced photoaging was observed by gross physical appearance and histopathological analysis. Oxidative stress and melanin synthesis were analyzed using biochemical method. Western blotting was applied to analyze the phosphorylation and expression levels of matrix metalloproteinase-1 (MMP-1), collagen I, and proteins involved in the mitogen-activated protein kinase (MAPK) signaling pathways (p38, ERK, and JNK). The results show that SPP has a significant therapeutic effect on UV-induced photoaging of skin and improves and restores appearance and tissue structure of mouse skin. The major mechanism may be related to reduction of expression level of MMP-1 and enhancement of collagen I production via inhibition of MAPK signaling pathway after scavenging of excess reactive oxygen species (ROS) in the UV-induced photoaged skin of mice. Meanwhile, it may also be involved in reducing melanin content by inhibiting tyrosinase activity after scavenging excess ROS in the UV-induced photoaged skin of mice. Therefore, SPP could be a good substance to treat photoaging skin. Taking cost-effectiveness and efficacy into consideration, the optimal concentration of SPP for treating photoaging skin could be 100 mg/g.

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

Pre-mRNA processing factor 4B (PRP4) has previously been shown to induce epithelial-mesenchymal transition (EMT) and drug resistance in cancer cell lines. As melanin plays an important photoprotective role in the risk of sun-induced skin cancers, we have investigated whether PRP4 can induce drug resistance and regulate melanin biosynthesis in a murine melanoma (B16F10) cell line. Cells were incubated with a crucial melanogenesis stimulator, alpha-melanocyte-stimulating hormone, followed by transfection with PRP4. This resulted in the inhibition of the production of melanin via the downregulation of adenylyl cyclase-cyclic adenosine 3′,5′-monophosphate (AC)–(cAMP)–tyrosinase synthesis signaling pathway. Inhibition of melanin production by PRP4 leads to the promotion of carcinogenesis and induced drug resistance in B16F10 cells. Additionally, PRP4 overexpression upregulated the expression of β-arrestin 1 and desensitized the extracellular calcium-sensing receptor (CaSR), which in turn, inhibited the influx of extracellular Ca²⁺ ions. The decreased influx of Ca²⁺ was confirmed by a decreased expression level of calmodulin. We have demonstrated that transient receptor potential cation channel subfamily C member 1 was involved in the influx of CaSR-induced Ca²⁺ via a decreasing level of its expression. Furthermore, PRP4 overexpression downregulated the expression of AC, decreased the synthesis of cAMP, and modulated the actin cytoskeleton by inhibiting the expression of Ras homolog family member A (RhoA). Our investigation suggests that PRP4 inhibits the production of melanin in B16F10 cells, blocks the influx of Ca²⁺ through desensitization of CaSR, and modulates the actin cytoskeleton through downregulating the AC–cAMP pathway; taken together, these observations collectively lead to the promotion of skin carcinogenesis.

Characterization and Optimization of the Tyrosinase Inhibitory Activity of Vitis amurensis Root Using LC-Q-TOF-MS Coupled with a Bioassay and Response Surface Methodology

Vitis amurensis roots have been reported to have the potential for skin whitening through the evaluation of melanogenesis and tyrosinase inhibitory activities. In this study, V. amurensis roots were utilized to quickly select whitening ingredients using LC-Q-TOF-MS coupled with tyrosinase inhibitory assay, and to optimize the extraction process for use as a skin whitening functional material by response surface methodology. Results showed that V. amurensis roots exhibited tyrosinase inhibitory effects by two stilbene oligomers, ε-viniferin (1) and vitisin B (2), as predicted by LC-Q-TOF-MS coupled with bioassay. The optimal extraction conditions (methanol concentration 66%, solvent volume 140 mL, and extraction time 100 min) for skin whitening ingredients were established with the yields 6.20%, and tyrosinase inhibitory activity was 87.27%. The relationship between each factor and its corresponding response was confirmed by Pearson’s correlation analysis. The solvent volume showed clear linear relationship with yields, and methanol concentration had a strong linear relationship with tyrosinase inhibitory activity for compounds 1 and 2, as well as their combination. Overall, LC-Q-TOF-MS coupled with bioassay was proved to have the potential to effectively find new active constituents, as well as known active constituents; vitisin B can be proposed as a new natural potential whitening agent.

Anti-Photoaging and Anti-Melanogenesis Effects of Fucoidan Isolated from Hizikia fusiforme and Its Underlying Mechanisms

Previous studies suggested that fucoidan with a molecular weight of 102.67 kDa, isolated from Hizikia fusiforme, possesses strong antioxidant activity. To explore the cosmeceutical potential of fucoidan, its anti-photoaging and anti-melanogenesis effects were evaluated in the present study. The anti-photoaging effect was investigated in ultraviolet (UV) B-irradiated human keratinocytes (HaCaT cells), where fucoidan effectively reduced the intracellular reactive oxygen species level and improved the viability of the UVB-irradiated cells without any cytotoxic effects. Moreover, fucoidan significantly decreased UVB-induced apoptosis in HaCaT cells by regulating the protein expression of Bax, Bcl-xL, PARP, and Caspase-3 in HaCaT cells in a concentration-dependent manner. The anti-melanogenesis effect of fucoidan was evaluated in B16F10 melanoma cells that had been stimulated with alpha-melanocyte-stimulating hormone (α-MSH), and fucoidan treatment remarkably inhibited melanin synthesis in α-MSH-stimulated B16F10 cells. Further studies indicated that fucoidan significantly suppressed the expression of tyrosinase and tyrosinase-related protein-1 and -2 (TRP-1 and-2) in B16F10 cells by down-regulating microphthalmia-associated transcription factor (MITF) through regulation of the ERK–MAPK (extracellular signal regulated kinase-mitogen activated protein kinase) pathway. Taken together, these results suggest that fucoidan isolated from H. fusiforme possesses strong anti-photoaging and anti-melanogenesis activities and can be used as an ingredient in the pharmaceutical and cosmeceutical industries.

Neobavaisoflavone Inhibits Melanogenesis through the Regulation of Akt/GSK-3β and MEK/ERK Pathways in B16F10 Cells and a Reconstructed Human 3D Skin Model

Previous studies have confirmed the anti-melanogenic effect of the aerial part of Pueraria lobata, however, due to its inherent color, P. lobata has limited commercial use. In this study, an extract (GALM-DC) of the aerial part of P. lobata having improved color by the use of activated carbon was obtained. Furthermore, the active compound neobavaisoflavone (NBI) was identified from GALM-DC. The effect of NBI on melanogenesis, tyrosinase activity, α-glucosidase activity, and mechanism of action in melanocytes was investigated. Tyrosinase activity, melanin contents and the expression of melanin-related genes and proteins were determined in B16F10 cells. NBI reduced melanin synthesis and tyrosinase activity. Furthermore, NBI treatment reduced the mRNA and protein expression levels of MITF, TRP-1, and tyrosinase. NBI also works by phosphorylating and activating proteins that inhibit melanogenesis, such as GSK3β and ERK. Specific inhibitors of Akt/GSK-3β (LY294002) and MEK/ERK (PD98059) signaling prevented the inhibition of melanogenesis by NBI. NBI inhibited melanin production through the regulation of MEK/ERK and Akt/GSK-3β signaling pathways in α-MSH-stimulated B16F10 cells. NBI suppresses tyrosinase activity and melanogenesis through inhibition of α-glucosidase activity. Besides, NBI significantly reduced melanogenesis in a reconstructed human 3D skin model. In conclusion, these results suggest that NBI has potential as a skin-whitening agent for hyperpigmentation.

Betulinic Acid and Brosimine B Hybrid Derivatives as Potential Agents against Female Cancers

Background:

Cancer is a multifactorial disease, representing one of the leading causes of death worldwide. On a global estimate, breast cancer is the most frequently occurring cancer in women and cervical cancer, the fourth most common. Both types of cancer remain the major cause of cancer-related mortality in developing countries. A strategy for rational drug design is hybridization, which aims to bring together in one molecule, two or more pharmacophores in order to reach several biological targets.

Objective:

The objective of this work was to develop new hybrids based on natural pharmacophores: Betulinic acid (1) and brosimine b (2), active in female cancer cell lines.

Methods:

The coupling reactions were carried out by Steglich esterification. Different compounds were designed for the complete and simplified structural hybridization of molecules. The anticancer activities of the compounds were evaluated in human cervical adenocarcinoma (HeLa), human cervical metastatic epidermoid carcinoma (ME-180), and human breast adenocarcinoma (MCF-7) cell lines.

Results:

Hybrid 3 presented higher potency (IC50 = 9.2 ± 0.5μM) and SI (43.5) selectively in MCF-7 cells (in relation to Vero cells) with its cytotoxic effect occurring via apoptosis. In addition, compound 6 showed activity in MCF-7 and HeLa cells with intermediate potency, but with high efficacy, acting via apoptosis as well.

Conclusion:

In this context, we showed that the combination of two complex structures generated the development of hybrids with differing inhibitory profiles and apoptotic modes of action, thus representing potential alternatives in female cancer treatment.

Betulin and its derivatives as novel compounds with different pharmacological effects

Betulin (B) and Betulinic acid (BA) are natural pentacyclic lupane-structure triterpenoids which possess a wide range of pharmacological activities. Recent evidence indicates that B and BA have several properties useful for the treatment of metabolic disorders, infectious diseases, cardiovascular disorders, and neurological disorders. In the current review, we discuss B and BA structures and derivatives and then comprehensively explain their pharmacological effects in relation to various diseases. We also explain antiviral, antibacterial and anti-cancer effects of B and BA. Finally, we discuss the delivery methods, in which these compounds most effectively target different systems.

Discovery of new depigmenting compounds and their efficacy to treat hyperpigmentation: Evidence from in vitro study

Human skin pigmentation is a result of constitutive and facultative pigmentation. Facultative pigmentation is frequently stimulated by UV radiation, pharmacologic drugs, and hormones whereby leads to the development of abnormal skin hyperpigmentation. To date, many state-of-art depigmenting compounds have been studied using in vitro model to treat hyperpigmentation problems for cosmetic dermatological applications; little attention has been made to compare the effectiveness of these depigmenting compounds and their mode of actions. In this present article, new and recent depigmenting compounds, their melanogenic pathway targets, and modes of action are reviewed. This article compares the effectiveness of these new depigmenting compounds to modulate several melanogenesis-regulatory enzymes and proteins such as tyrosinase (TYR), TYR-related protein-1 (TRP1), TYR-related protein-2 (TRP2), microphthalmia-associated transcription factor (MITF), extracellular signal-regulated kinase (ERK) and N-terminal kinases (JNK) and mitogen-activated protein kinase p38 (p38 MAPK). Other evidences from in vitro assays such as inhibition on melanosomal transfer, proteasomes, nitric oxide, and inflammation-induced melanogenesis are also highlighted. This article also reviews analytical techniques in different assays performed using in vitro model as well as their advantages and limitations. This article also provides an insight on recent finding and re-examination of some protocols as well as their effectiveness and reliability in the evaluation of depigmenting compounds. Evidence and support from related patents are also incorporated in this present article to give an overview on current patented technology, latest trends, and intellectual values of some depigmenting compounds and protocols, which are rarely highlighted in the literatures.

Anti-melanogenesis potential of a new series of Morita-Baylis-Hillman adducts in B16F10 melanoma cell line

Melanin is a natural polymer pigment which provides skin photoprotection against ultraviolet radiation. An excessive synthesis of melanin leads to hyperpigmentation disorders. Tyrosinase catalyzes the rate limiting steps on melanogenesis. Therefore, tyrosinase inhibitors have potential applications in medicine and cosmetic fields. We carried out herein the screening of a family of cyclic Morita-Baylis-Hillman adducts (MBH) to find out their effects on tyrosinase activity and on melanogenesis in murine melanoma B16F10 cell line. Kinetic analysis of tyrosinase inhibition showed that compounds 1a (2-hydroxymethyl) cyclohex-2-enone) and 3f (diethyl (1-(6-oxocyclohex-1-en-1-yl) ethyl-phosphonate) were competitive inhibitors, whereas the compound 2b (6-oxocyclohex-1-en-1-yl) ethyl acetate) was a non-competitive one. Additionally we have found that (1a, 2b and 3f) compounds had a strong melanogenesis inhibition effect in isobutylmethylxanthine (IBMX)-treated murine melanoma B16F10 cells when tested at low and non cytotoxic dose (10-50 µM), by attenuating the melanin production, intracellular tyrosinase activity and tyrosinase expression. Thus, we suggest that these compounds could be used as effective skin-whitening agents.

Vitis amurensis Rupr: A review of chemistry and pharmacology

PURPOSE

Vitis amurensis Rupr. from the family Vitaceae, is a grape species native to the Asian continent. It is a highly attractive plant, used widely worldwide. It has been used for several hundred years as a traditional Chinese herb. The review focuses on the botanical description, traditional uses, phytochemistry, and the biological activities of Vitis amurensis Rupr. to evaluate its therapeutic potential uses.

METHODS

This review summarizes the published data concerning the botanical aspects, traditional usage, phytochemistry, and pharmacology of Vitis amurensis Rupr., to evaluate its therapeutic potential as an important source of natural compounds with effect activities that benefit human health.

RESULTS

Vitis amurensis Rupr. has been used for several hundred years as a traditional Chinese herb to treat stranguria, rheumatoid arthritis-associated edema, chronic hepatitis, nephritis, chronic arthritis and traumatic hemorrhage. It is a particularly rich source of the oligostilbenes, flavonoids, and anthocyanins, phytochemicals that are associated with antioxidant, anti-inflammatory, antibacterial and cardioprotective activities. Due to the presence of a multitude of bioactives, a wide array of pharmacological activities have been ascribed to different parts of this herb and individual compounds, which include antioxidant, antimicrobial, anti-inflammatory, anticancer, anti-aging, anti-melanogenic, anti-allergic and anti-viral.

CONCLUSION

From a health perspective, Vitis amurensis Rupr. presents excellent options for treating various diseases due to its bioactive compounds (drug candidates) that exhibit important activities or for developing new products.

Inhibition of melanogenesis by jineol from Scolopendra subspinipes mutilans via MAP-Kinase mediated MITF downregulation and the proteasomal degradation of tyrosinase

In this study, the authors investigated the anti-melanogenic effects of 3,8-dihydroxyquinoline (jineol) isolated from Scolopendra subspinipes mutilans, the mechanisms responsible for its inhibition of melanogenesis in melan-a cells, and its antioxidant efficacy. Mushroom tyrosinase activities and melanin contents were determined in melan-a cells, and the protein and mRNA levels of MITF, tyrosinase, TYRP-1, and TYRP-2 were assessed. Jineol exhibited significant, concentration-dependent antioxidant effects as determined by DPPH, ABTS, CUPRAC, and FRAP assays. Jineol significantly inhibited mushroom tyrosinase activity by functioning as an uncompetitive inhibitor, and markedly inhibited melanin production and intracellular tyrosinase activity in melan-a cells. In addition, jineol abolished the expressions of tyrosinase, TYRP-1, TYRP-2, and MITF, thereby blocking melanin production and interfering with the phosphorylations of ERK1/2 and p38. Furthermore, specific inhibitors of ERK1/2 and p38 prevented melanogenesis inhibition by jineol, and the proteasome inhibitor (MG-132) prevented jineol-induced reductions in cellular tyrosinase levels. Taken together, jineol was found to stimulate MAP-kinase (ERK1/2 and p38) phosphorylation and the proteolytic degradation pathway, which led to the degradations of MITF and tyrosinase, and to suppress the productions of melanin.

Cudraflavone C Induces Tumor-Specific Apoptosis in Colorectal Cancer Cells through Inhibition of the Phosphoinositide 3-Kinase (PI3K)-AKT Pathway

Cudraflavone C (Cud C) is a naturally-occurring flavonol with reported anti-proliferative activities. However, the mechanisms by which Cud C induced cytotoxicity have yet to be fully elucidated. Here, we investigated the effects of Cud C on cell proliferation, caspase activation andapoptosis induction in colorectal cancer cells (CRC). We show that Cud C inhibits cell proliferation in KM12, Caco-2, HT29, HCC2998, HCT116 and SW48 CRC but not in the non-transformed colorectal epithelial cells, CCD CoN 841. Cud C induces tumor-selective apoptosis via mitochondrial depolarization and activation of the intrinsic caspase pathway. Gene expression profiling by microarray analyses revealed that tumor suppressor genes EGR1, HUWE1 and SMG1 were significantly up-regulated while oncogenes such as MYB1, CCNB1 and GPX2 were down-regulated following treatment with Cud C. Further analyses using Connectivity Map revealed that Cud C induced a gene signature highly similar to that of protein synthesis inhibitors and phosphoinositide 3-kinase (PI3K)-AKT inhibitors, suggesting that Cud C might inhibit PI3K-AKT signaling. A luminescent cell free PI3K lipid kinase assay revealed that Cud C significantly inhibited p110β/p85α PI3K activity, followed by p120γ, p110δ/p85α, and p110α/p85α PI3K activities. The inhibition by Cud C on p110β/p85α PI3K activity was comparable to LY-294002, a known PI3K inhibitor. Cud C also inhibited phosphorylation of AKT independent of NFκB activity in CRC cells, while ectopic expression of myristoylated AKT completely abrogated the anti-proliferative effects, and apoptosis induced by Cud C in CRC. These findings demonstrate that Cud C induces tumor-selective cytotoxicity by targeting the PI3K-AKT pathway. These findings provide novel insights into the mechanism of action of Cud C, and indicate that Cud C further development of Cud C derivatives as potential therapeutic agents is warranted.

The activation of melanogenesis by p-CREB and MITF signaling with extremely low-frequency electromagnetic fields on B16F10 melanoma

Melanin in the skin determines the skin color, and decreased melanin causes many hypopigmentation disorders and increased damage to skin by ultraviolet B (UVB) light irradiation. Here, we stimulate melanogenesis in B16F10 melanoma cells by using specific frequencies of ELF-EMFs. In this study, we focus on the melanogenesis of EMF-ELFs and find that 60-75Hz ELF-EMFs upregulate melanin synthesis by stimulated expression of tyrosinase and TRP-1 through inhibition of phosphorylation ERK, activation of CREB, and MITF up-regulation in B16F10 melanoma cells. The results show that 60-75Hz ELF-EMFs significantly increase secreted melanin, cellular melanin content, and tyrosinase activity, and the cell mitochondria activity, cell viability, and cell membrane condition are unchanged. Furthermore, the protein expression level of MITF and p-CREB signaling pathway are significantly increased. Moreover, 60Hz ELF-EMFs reduce the phosphorylate of ERK in B16F10 melanoma cells. These findings indicate that stimulation of melanogenesis by using ELF-EMFs has therapeutic potential for treating hypopigmentation disorders such as vitiligo.

Phenylacylphenol derivatives with anti-melanogenic activity from Stewartia pseudocamellia

Three new phenylacylphenol derivatives, stewartianol (1), deoxystewartianol-4'-O-arabinoglucoside (2), and stewartianol-3-O-glucoside (3), along with nine known compounds, methylesculin (4), fraxoside (5), fraxetin (6), scopletin (7), (+)-dihydromyricetin (8), (+)-taxifolin-7-O-β-D-glucose (9), (+)-taxifolin (10), (+)-dihydrokaempferol-7-O-β-D-glucose (11), and 3-acetyl-ursolic acid (12), were isolated from the twigs of Stewartia pseudocamellia; commonly used as folk medicine in Korea. The structures of the isolated compounds were identified using spectroscopic analysis, including 1D, 2D NMR, MS and compared with published data. The compounds were tested for their anti-melanogenic activity in cultured murine B16 melanoma cells. Stewartianol (1) and stewartianol-3-O-glucoside (3) showed an inhibitory effect significantly on melanogenesis in a concentration-dependent manner.

Betulinic acid exerts anti-hepatitis C virus activity via the suppression of NF-κB- and MAPK-ERK1/2-mediated COX-2 expression

BACKGROUND AND PURPOSE

This study was designed to evaluate the effect of betulinic acid (BA), extracted from Avicennia marina, on the replication of hepatitis C virus (HCV) and to investigate the mechanism of this BA-mediated anti-HCV activity.

EXPERIMENTAL APPROACH

HCV replicon and infectious systems were used to evaluate the anti-HCV activity of BA. Exogenous COX-2 or knock-down of COX-2 expression was used to investigate the role of COX-2 in the anti-HCV activity of BA. The effects of BA on the phosphorylation of NF-κB and on kinases in the MAPK signalling pathway were determined. The anti-HCV activity of BA in combination with other HCV inhibitors was also determined to assess its use as an anti-HCV supplement.

KEY RESULTS

BA inhibited HCV replication in both Ava5 replicon cells and in a cell culture-derived infectious HCV particle system. Treatment with a combination of BA and IFN-α, the protease inhibitor telaprevir or the NS5B polymerase inhibitor sofosbuvir resulted in the synergistic suppression of HCV RNA replication. Exogenous overexpression of COX-2 gradually attenuated the inhibitory effect of BA on HCV replication, suggesting that BA reduces HCV replication by suppressing the expression of COX-2. In particular, BA down-regulated HCV-induced COX-2 expression by reducing the phosphorylation of NF-κB and ERK1/2 of the MAPK signalling pathway.

CONCLUSIONS AND IMPLICATIONS

BA inhibits HCV replication by suppressing the NF-κB- and ERK1/2-mediated COX-2 pathway and may serve as a promising compound for drug development or as a potential supplement for use in the treatment of HCV-infected patients.

Novel cancer chemotherapy hits by molecular topology: dual Akt and Beta-catenin inhibitors

Background and Purpose

Colorectal and prostate cancers are two of the most common types and cause of a high rate of deaths worldwide. Therefore, any strategy to stop or at least slacken the development and progression of malignant cells is an important therapeutic choice. The aim of the present work is the identification of novel cancer chemotherapy agents. Nowadays, many different drug discovery approaches are available, but this paper focuses on Molecular Topology, which has already demonstrated its extraordinary efficacy in this field, particularly in the identification of new hit and lead compounds against cancer. This methodology uses the graph theoretical formalism to numerically characterize molecular structures through the so called topological indices. Once obtained a specific framework, it allows the construction of complex mathematical models that can be used to predict physical, chemical or biological properties of compounds. In addition, Molecular Topology is highly efficient in selecting and designing new hit and lead drugs. According to the aforementioned, Molecular Topology has been applied here for the construction of specific Akt/mTOR and β-catenin inhibition mathematical models in order to identify and select novel antitumor agents.

Experimental Approach

Based on the results obtained by the selected mathematical models, six novel potential inhibitors of the Akt/mTOR and β-catenin pathways were identified. These compounds were then tested in vitro to confirm their biological activity.

Conclusion and Implications

Five of the selected compounds, CAS n° 256378-54-8 (Inhibitor n°1), 663203-38-1 (Inhibitor n°2), 247079-73-8 (Inhibitor n°3), 689769-86-6 (Inhibitor n°4) and 431925-096 (Inhibitor n°6) gave positive responses and resulted to be active for Akt/mTOR and/or β-catenin inhibition. This study confirms once again the Molecular Topology’s reliability and efficacy to find out novel drugs in the field of cancer.

The peripheral clock regulates human pigmentation

Although the regulation of pigmentation is well characterized, it remains unclear whether cell-autonomous controls regulate the cyclic on-off switching of pigmentation in the hair follicle (HF). As human HFs and epidermal melanocytes express clock genes and proteins, and given that core clock genes (PER1, BMAL1) modulate human HF cycling, we investigated whether peripheral clock activity influences human HF pigmentation. We found that silencing BMAL1 or PER1 in human HFs increased HF melanin content. Furthermore, tyrosinase expression and activity, as well as TYRP1 and TYRP2 mRNA levels, gp100 protein expression, melanocyte dendricity, and the number gp100+ HF melanocytes, were all significantly increased in BMAL1 and/or PER1-silenced HFs. BMAL1 or PER1 silencing also increased epidermal melanin content, gp100 protein expression, and tyrosinase activity in human skin. These effects reflect direct modulation of melanocytes, as BMAL1 and/or PER1 silencing in isolated melanocytes increased tyrosinase activity and TYRP1/2 expression. Mechanistically, BMAL1 knockdown reduces PER1 transcription, and PER1 silencing induces phosphorylation of the master regulator of melanogenesis, microphthalmia-associated transcription factor, thus stimulating human melanogenesis and melanocyte activity in situ and in vitro. Therefore, the molecular clock operates as a cell-autonomous modulator of human pigmentation and may be targeted for future therapeutic strategies.