Pan-EGFR Inhibitor Dacomitinib Resensitizes Paclitaxel and Induces Apoptosis via Elevating Intracellular ROS Levels in Ovarian Cancer SKOV3-TR Cells.

Paclitaxel is still used as a standard first-line treatment for ovarian cancer. Although paclitaxel is effective for many types of cancer, the emergence of chemoresistant cells represents a major challenge in chemotherapy. Our study aimed to analyze the cellular mechanism of dacomitinib, a pan-epidermal growth factor receptor (EGFR) inhibitor, which resensitized paclitaxel and induced cell cytotoxicity in paclitaxel-resistant ovarian cancer SKOV3-TR cells. We investigated the significant reduction in cell viability cotreated with dacomitinib and paclitaxel by WST-1 assay and flow cytometry analysis. Dacomitinib inhibited EGFR family proteins, including EGFR and HER2, as well as its downstream signaling proteins, including AKT, STAT3, ERK, and p38. In addition, dacomitinib inhibited the phosphorylation of Bad, and combination treatment with paclitaxel effectively suppressed the expression of Mcl-1. A 2'-7'-dichlorodihydrofluorescein diacetate (DCFH-DA) assay revealed a substantial elevation in cellular reactive oxygen species (ROS) levels in SKOV3-TR cells cotreated with dacomitinib and paclitaxel, which subsequently mediated cell cytotoxicity. Additionally, we confirmed that dacomitinib inhibits chemoresistance in paclitaxel-resistant ovarian cancer HeyA8-MDR cells. Collectively, our research indicated that dacomitinib effectively resensitized paclitaxel in SKOV3-TR cells by inhibiting EGFR signaling and elevating intracellular ROS levels.

Nodakenin Inhibits Melanogenesis Via the ERK/MSK1 Signaling Pathway.

The aim of the present study was to investigate the potential inhibitory effects of nodakenin, a coumarin glucoside derivative from the root extract of Angelica gigas Nakai (AGN), on melanogenesis and its underlying mechanisms in B16F10 melanoma cells. The inhibitory effects of nodakenin on melanogenesis were evaluated by determining melanin contents and tyrosinase activity in α -melanocyte stimulating hormone (α-MSH)-treated B16F10 melanoma cells. The mechanisms associated with the anti-pigmentation effect of nodakenin were investigated by quantitative real-time PCR and immunoblotting analysis. Using the UVB-irradiated conditioned media culture system and UVB-irradiated co-cultivation system of HaCaT keratinocytes and B16F10 melanoma cells mimicking in vivo melanin biosynthesis, the effect of nodakenin on melanin production was evaluated. Melanin content analysis showed that nodakenin decreased cellular melanin biosynthesis in α-MSH-treated B16F10 cells. Immunoblotting revealed that CREB phosphorylation, MITF, a mastering transcription factor of melanogenesis and its downstream genes tyrosinase, tyrosinase-related protein 1, and tyrosinase-related protein 2 were downregulated by nodakenin in a dose-dependent manner. Interestingly, nodakenin did not affect the phosphorylation of PKA and p38 MAPK but the phosphorylation of ERK1/2 and MSK1. In addition, the inhibition of melanin accumulation by nodakenin in the UVB-irradiated conditioned media culture system and UVB-irradiated co-cultivation system of HaCaT and B16F10 cells suggests that nodakenin has potential as an anti-pigmentation activity. These data suggest that nodakenin inhibits the melanogenesis in B16F10 cells by interfering the ERK/ MSK1/CREB axis and thus preventing MITF expression.

Daphnetin inhibits α-MSH-induced melanogenesis via PKA and ERK signaling pathways in B16F10 melanoma cells.

Daphnetin is a dehydroxylated derivative of coumarin isolated from Daphne species. However, the effect of daphnetin on melanogenesis has not been elucidated. This study aims to investigate the inhibitory effect of daphnetin on melanogenesis in α-melanocyte stimulating hormone (α-MSH)-treated B16F10 cells and its potential mechanism. Melanin content analysis and cellular tyrosinase activity assay showed that daphnetin inhibited melanin biosynthesis in α-MSH-treated B16F10 cells. Immunoblotting and qRT-PCR also indicated that daphnetin suppressed the expression of microphthalmia-associated transcription factor, a mastering transcription factor of melanogenesis and its downstream melanogenic enzymes including tyrosinase and tyrosinase-related proteins. Moreover, daphnetin downregulated the phosphorylation of PKA, ERK, MSK1, and CREB. Additionally, daphnetin inhibited melanin synthesis in UVB-irradiated HaCaT conditioned medium system suggesting that daphnetin has potential as an antipigmentation activity in a physiological skin condition. Our data propose that daphnetin inhibits melanogenesis via modulating both the PKA/CREB and the ERK/MSK1/CREB pathways.

Inhibition of Glutamine Uptake Resensitizes Paclitaxel Resistance in SKOV3-TR Ovarian Cancer Cell via mTORC1/S6K Signaling Pathway.

Ovarian cancer is a carcinoma that affects women and that has a high mortality rate. Overcoming paclitaxel resistance is important for clinical application. However, the effect of amino acid metabolism regulation on paclitaxel-resistant ovarian cancer is still unknown. In this study, the effect of an amino acid-deprived condition on paclitaxel resistance in paclitaxel-resistant SKOV3-TR cells was analyzed. We analyzed the cell viability of SKOV3-TR in culture conditions in which each of the 20 amino acids were deprived. As a result, the cell viability of the SKOV3-TR was significantly reduced in cultures deprived of arginine, glutamine, and lysine. Furthermore, we showed that the glutamine-deprived condition inhibited mTORC1/S6K signaling. The decreased cell viability and mTORC1/S6K signaling under glutamine-deprived conditions could be restored by glutamine and α-KG supplementation. Treatment with PF-4708671, a selective S6K inhibitor, and the selective glutamine transporter ASCT2 inhibitor V-9302 downregulated mTOR/S6K signaling and resensitized SKOV3-TR to paclitaxel. Immunoblotting showed the upregulation of Bcl-2 phosphorylation and a decrease in Mcl-1 expression in SKOV3-TR via the cotreatment of paclitaxel with PF-4708671 and V-9302. Collectively, this study demonstrates that the inhibition of glutamine uptake can resensitize SKOV3-TR to paclitaxel and represents a promising therapeutic target for overcoming paclitaxel resistance in ovarian cancer.

Diarylpropionitrile inhibits melanogenesis via protein kinase A/cAMP-response element-binding protein/microphthalmia-associated transcription factor signaling pathway in α-MSH-stimulated B16F10 melanoma cells.

Diarylpropionitrile (DPN), a selective agonist for estrogen receptor ß (ERß), has been reported to regulate various hormonal responses through activation of ERß in tissues including the mammary gland and brain. However, the effect of DPN on melanogenesis independent of ERß has not been studied. The aim of this study is to examine the possibility of anti-melanogenic effect of DPN and its underlying mechanism. Melanin contents and cellular tyrosinase activity assay indicated that DPN inhibited melanin biosynthesis in alpha-melanocyte stimulating hormone-stimulated B16F10 melanoma cell line. However, DPN had no direct influence on in vitro tyrosinase catalytic activity. On the other hand, 17ß-estradiol had no effect on inhibition of melanogenesis, suggesting that the DPN-mediated suppression of melanin production was not related with estrogen signaling pathway. Immunoblotting analysis showed that DPN down-regulated the expression of microphthalmia-associated transcription factor (MITF), a central transcription factor of melanogenesis and its down-stream genes including tyrosinase, tyrosinase-related protein (TRP)-1, and TRP-2. Also, DPN attenuated the phosphorylation of protein kinase A (PKA) and cAMP-response element-binding protein (CREB). Additionally, DPN suppressed the melanin synthesis in UVB-irradiated HaCaT conditioned media culture system suggesting that DPN has potential as an anti-melanogenic activity in physiological conditions. Collectively, our data show that DPN inhibits melanogenesis via downregulation of PKA/CREB/MITF signaling pathway.

E3 ligase RCHY1 negatively regulates HDAC2.

HDAC2, one of the class I histone deacetylase regulates epigenetic landscape through histone modification. Because HDAC2 is overexpressed in many cancers, cancer therapeutics against HDAC2 have been developed. Here we show novel mechanism of HDAC2 regulation by E3 ligase RCHY1. We found inverse correlation RCHY1 and HDAC2 levels in tumor tissue from six independent dataset using meta-analysis. Ectopic expression of RCHY1 decreased the level of HDAC2 from cancer cells including p53 wildtype, mutant and null cells. In addition, HDAC2 was increased by RCHY1 knockdown. RCHY1 directly interacts with HDAC2. Ectopic expression of wild type but not RING mutant RCHY1 increased HDAC2 levels. These data provide an evidence that RCHY1 negatively regulates HDAC2.

Perphenazine Attenuates the Pro-Inflammatory Responses in Mouse Models of Th2-Type Allergic Dermatitis.

Developing dermatitis therapeutics has been faced with challenges including adverse effects of topical steroid and high cost of new developing drugs. Here, we found the expression levels of dopamine receptor D2 is higher in skin biopsies of dermatitis patients and an oxazolone-induced animal model of dermatitis. We used perphenazine, an FDA-approved dopamine receptor antagonist to determine the therapeutic effect. Two different animal models including 12-o-tetradecanoylphorbol-13-acetate (TPA) and oxazolone (OXA)-induced dermatitis were employed. TPA and OXA-mediated ear swelling was attenuated by perphenazine. Moreover, perphenazine inhibited infiltrated mast cells into lesion area. We found levels of serum IgE, histamine and cytokines are decreased in mice cotreated with perphenazine and OXA compared to OXA-treated mice. Overall, this is a first study showing that the FDA-approved, anti-psychotic drug, perphenazine, alleviates animal models of dermatitis.

Metformin ameliorates animal models of dermatitis.

Metformin, a potent AMPK activator is the most commonly used drug for diabetes. According to recent reports, metformin lowers the risk of diabetic complications and inflammatory diseases. We found the expression levels of AMPK subunits including PRKAA1, PRKAA2, PRKAB1 and PRKAB2 are decreased in skin biopsies of dermatitis patients from multiple datasets. Interestingly, metformin treatment ameliorates dermatitis symptom in animal model of dermatitis using O-tetradecanoylphorbol-13-acetate (TPA). Especially, the levels of epidermis and dermis thickness were decreased by metformin. We found NFκB activity as well as of gene expression associated with collagen synthesis are attenuated by metformin treatment. These results suggest that metformin treatment alleviates animal model of dermatitis.

Mdm2 is required for HDAC3 monoubiquitination and stability.

HDAC3, one of the class I histone deacetylase modulates epigenetic landscape through histone modification. HDAC3 also interacts with non-histone proteins including p53 for deacetylation. Moreover, HDAC3 serves as a transcriptional repressor, interacting with NCor1/SMRT complex. Although HDAC3 plays a critical role for cellular homeostasis, regulatory mechanism of HDAC3 have been poorly understood. Here we report a novel regulatory mechanism of HDAC3 about its monoubiquitination and stabilization by Mdm2. HDAC3 levels were increased by ectopic expression of Mdm2 and decreased by Mdm2 ablation in various cell lines. We found that Mdm2 directly interacts with HDAC3 and induces HDAC3 protein levels without alteration of mRNA levels. Ectopic expression of wild type but not RING mutant of Mdm2 increased HDAC3 monoubiquitination. In addition, MdmX is beneficial for mdm2-mediated HDAC3 regulation. Ablation of Mdm2 and Mdm2/MdmX decreased cell migration along with the decrease of HDAC3 levels. These data provide an evidence that Mdm2 positively regulates HDAC3 monoubiquitination and stability.

TRIAD1 Is a Novel Transcriptional Target of p53 and Regulates Nutlin-3a-Induced Cell Death.

Nutlin-3a is a non-genotoxic, p53-activating, MDM2 inhibitor being investigated as an anticancer agent. Although Nutlin-3a selectively antagonizes the ubiquitin E3 ligase activity of MDM2, its efficacy is not entirely regulated by MDM2 levels in cancer cells. Here, we report that the cytotoxic effects of Nutlin-3a are regulated by TRIAD1 via a positive feedback loop with p53. We found that Nutlin-3a enhanced TRIAD1 transcription in a p53-dependent manner. Using in silico analysis and promoter luciferase assays, we demonstrated that p53-mediated transcription of TRIAD1 is mediated by a p53 consensus sequence in the TRIAD1 promoter region. Silencing TRIAD1 expression in wild-type p53 (p53WT ) cancer cells suppressed Nutlin-3a-mediated p53 activation and p53 target gene expression. These effects were enhanced in TRIAD1-overexpressing p53WT cancer cells, but not in p53-deficient cancer cells. Furthermore, TRIAD1 knockdown significantly reduced the growth inhibitory and cytotoxic effects of Nutlin-3a in p53WT cancer cells, as demonstrated by cell viability assays, cell cycle analysis, clonogenic growth, and soft-agar colony forming assays. Together, these data indicate that TRIAD1 regulates Nutlin-3a-mediated p53 activation and the cytotoxic activity of Nutlin-3a. J. Cell. Biochem. 118: 1733-1740, 2017. © 2016 Wiley Periodicals, Inc.

Titrated extract of Centella asiatica increases hair inductive property through inhibition of STAT signaling pathway in three-dimensional spheroid cultured human dermal papilla cells.

Dermal papilla (DP) is a pivotal part of hair follicle, and the smaller size of the DP is related with the hair loss. In this study, we investigated the effect of titrated extract of Centella asiatica (TECA) on hair growth inductive property on 3D spheroid cultured human DP cells (HDP cells). Significantly increased effect of TECA on cell viability was only shown in 3D sphered HPD cells, not in 2D cultured HDP cells. Also, TECA treatment increased the sphere size of HDP cells. The luciferase activity of STAT reporter genes and the expression of STAT-targeted genes, SOCS1 and SOCS3, were significantly decreased. Also, TECA treatment increased the expression of the hair growth-related signature genes in 3D sphered HDP cells. Furthermore, TECA led to downregulation of the level of phosphorylated STAT proteins in 3D sphered HDP cells. Overall, TECA activates the potential of hair inductive capacity in HDP cells.

Cooperative actions of p21WAF1 and p53 induce Slug protein degradation and suppress cell invasion.

How the p53 transcription factor/tumor suppressor inhibits cell invasion is poorly understood. We demonstrate that this function of p53 requires its direct interaction with p21(WAF1), a transcriptional target of p53, and that both p21 and p53 bind to Slug, which promotes cell invasion. Functional studies reveal that p21 and p53 cooperate to facilitate Mdm2-dependent Slug degradation and that this p53 function is mimicked by p53(R273H), a mutant lacking trans-activating activity. These actions of p21 and p53 are induced by γ-irradiation of cells and also operate in vivo. This is the first study to elucidate a mechanism involving p53 and p21 cooperation.

Effects of er-miao-san extracts on TNF-alpha-induced MMP-1 expression in human dermal fibroblasts.

BACKGROUND: Various health benefits have been attributed to Er-Miao-San (EMS), a traditional Chinese herbal formulation that contains equal amounts of cortex phellodendri (Phellodendron amurense Ruprecht) and rhizoma atractylodis (Atractylodes lancea D.C). However, its effect on the anti-inflammatory activity in human dermal fibroblasts (HDFs) and the mechanism underlying this effect are unknown. RESULTS: This study investigated the effects of EMS on TNF-α-induced MMP-1 expression in HDFs. Our data show that EMS inhibited TNF-α-induced MMP-1 expression in a concentration-dependent manner. Interestingly, EMS maintained IκB content without inhibiting the phosphorylation of MAPKs, which are well-established upstream kinases of NF-κB. Moreover, EMS reduced the level of nuclear p65 protein in HDFs. Luciferase assay revealed that EMS inhibits the transcriptional activity of NF-κB by stabilizing IκB. Our results show that EMS exerts its anti-inflammatory effect by inhibiting NF-κB-regulated genes such as IL-1ß and IL-8. Moreover, EMS effectively inhibited TNF-α-induced expression of MMP-1 via the NF-κB pathway. CONCLUSIONS: Taken together, our data suggest that EMS could potentially be used as an anti-inflammatory and anti-aging treatment.

Arctiin blocks hydrogen peroxide-induced senescence and cell death though microRNA expression changes in human dermal papilla cells.

BACKGROUND: Accumulating evidence indicates that reactive oxygen species (ROS) are an important etiological factor for the induction of dermal papilla cell senescence and hair loss, which is also known alopecia. Arctiin is an active lignin isolated from Arctium lappa and has anti-inflammation, anti-microbial, and anti-carcinogenic effects. In the present study, we found that arctiin exerts anti-oxidative effects on human hair dermal papilla cells (HHDPCs). RESULTS: To better understand the mechanism, we analyzed the level of hydrogen peroxide (H2O2)-induced cytotoxicity, cell death, ROS production and senescence after arctiin pretreatment of HHDPCs. The results showed that arctiin pretreatment significantly inhibited the H2O2-induced reduction in cell viability. Moreover, H2O2-induced sub-G1 phase accumulation and G2 cell cycle arrest were also downregulated by arctiin pretreatment. Interestingly, the increase in intracellular ROS mediated by H2O2 was drastically decreased in HHDPCs cultured in the presence of arctiin. This effect was confirmed by senescence associated-beta galactosidase (SA-ß-gal) assay results; we found that arctiin pretreatment impaired H2O2-induced senescence in HHDPCs. Using microRNA (miRNA) microarray and bioinformatic analysis, we showed that this anti-oxidative effect of arctiin in HHDPCs was related with mitogen-activated protein kinase (MAPK) and Wnt signaling pathways. CONCLUSIONS: Taken together, our data suggest that arctiin has a protective effect on ROS-induced cell dysfunction in HHDPCs and may therefore be useful for alopecia prevention and treatment strategies.

Phloroglucinol Enhances Anagen Signaling and Alleviates H2O2-Induced Oxidative Stress in Human Dermal Papilla Cells.

Phloroglucinol (PG) is one of the abundant isomeric benzenetriols in brown algae. Due to its polyphenolic structure, PG exhibits various biological activities. However, the impact of PG on anagen signaling and oxidative stress in human dermal papilla cells (HDPCs) is unknown. In this study, we investigated the therapeutic potential of PG for improving hair loss. A non-cytotoxic concentration of PG increased anagen-inductive genes and transcriptional activities of ß-Catenin. Since several anagen-inductive genes are regulated by ß-Catenin, further experiments were performed to elucidate the molecular mechanism by which PG upregulates anagen signaling. Various biochemical analyses revealed that PG upregulated ß-Catenin signaling without affecting the expression of Wnt. In particular, PG elevated the phosphorylation of protein kinase B (AKT), leading to an increase in the inhibitory phosphorylation of glycogen synthase kinase 3 beta (GSK3ß) at serine 9. Treatment with the selective phosphoinositide 3-kinase/AKT inhibitor, LY294002, restored the increased AKT/GSK3ß/ß-Catenin signaling and anagen-inductive proteins induced by PG. Moreover, conditioned medium from PG-treated HDPCs promoted the proliferation and migration of human epidermal keratinocytes via the AKT signaling pathway. Subsequently, we assessed the antioxidant activities of PG. PG ameliorated the elevated oxidative stress markers and improved the decreased anagen signaling in hydrogen peroxide (H2O2)-induced HDPCs. The senescence-associated ß-galactosidase staining assay also demonstrated that the antioxidant abilities of PG effectively mitigated H2O2-induced senescence. Overall, these results indicate that PG potentially enhances anagen signaling and improves oxidative stress-induced cellular damage in HDPCs. Therefore, PG can be employed as a novel therapeutic component to ameliorate hair loss symptoms.

Deguelin Restores Paclitaxel Sensitivity in Paclitaxel-Resistant Ovarian Cancer Cells via Inhibition of the EGFR Signaling Pathway.

Background: Ovarian cancer is one of women's malignancies with the highest mortality among gynecological cancers. Paclitaxel is used in first-line ovarian cancer chemotherapy. Research on paclitaxel-resistant ovarian cancer holds significant clinical importance. Methods: Cell viability and flow cytometric assays were conducted at different time and concentration points of deguelin and paclitaxel treatment. Immunoblotting was performed to assess the activation status of key signaling molecules important for cell survival and proliferation following treatment with deguelin and paclitaxel. The fluo-3 acetoxymethyl assay for P-glycoprotein transport activity assay and cell viability assay in the presence of N-acetyl-L-cysteine were also conducted. Results: Cell viability and flow cytometric assays demonstrated that deguelin resensitized paclitaxel in a dose- and time-dependent manner. Cotreatment with deguelin and paclitaxel inhibited EGFR and its downstream signaling molecules, including AKT, ERK, STAT3, and p38 MAPK, in SKOV3-TR cells. Interestingly, cotreatment with deguelin and paclitaxel suppressed the expression level of EGFR via the lysosomal degradation pathway. Cotreatment did not affect the expression and function of P-glycoprotein. N-acetyl-L-cysteine failed to restore cell cytotoxicity when used in combination with deguelin and paclitaxel in SKOV3-TR cells. The expression of BCL-2, MCL-1, and the phosphorylation of the S155 residue of BAD were downregulated. Moreover, inhibition of paclitaxel resistance by deguelin was also observed in HeyA8-MDR cells. Conclusion: Our research showed that deguelin effectively suppresses paclitaxel resistance in SKOV3-TR ovarian cancer cells by downregulating the EGFR and its downstream signaling pathway and modulating the BCL-2 family proteins. Furthermore, deguelin exhibits inhibitory effects on paclitaxel resistance in HeyA8-MDR ovarian cancer cells, suggesting a potential mechanism for paclitaxel resensitization that may not be cell-specific. These findings suggest that deguelin holds promise as an anticancer therapeutic agent for overcoming chemoresistance in ovarian cancer.

Whitening and moisturizing enhancing effects of three-dimensional human adipose-derived mesenchymal stem cell-conditioned medium-containing cream.

BACKGROUND: High-functional cosmetic products combined with the concept of "treatment" cosmetics are being introduced to the market. Cosmetic products containing a skin-derived microbiome, a three-dimensional (3D) stem cell culture medium, and low-molecular-weight collagen are being introduced, and these products are leading the cosmeceutical market. We aimed to confirm the potential of a 3D stem cell culture medium-containing cream as a skin-whitening and moisturizing product. AIM: To determine the enhancing effects of a cream containing 3D adipose tissue-derived mesenchymal stem cell-conditioned media (3D ADMSC-CM) on whitening and moisturization. METHODS: The inhibitory activities of tyrosinase (TYR) and melanin were confirmed using 3D ADMSC-CM. Furthermore, hyaluronic acid expression in 3D ADMSC-CM was verified. The clinical efficacy of the cream containing 3D ADMSC-CM was established by evaluating its antioxidant properties and effects on skin tone, radiance, freckles, and moisturization. RESULTS: The use of 3D ADMSC-CM suppressed the inhibitory effects of TYR and melanin by approximately 24% and 33%, respectively, and increased the expression of hyaluronic acid synthase. A significant difference was observed after 4 weeks of using 3D ADMSC-CM in the skin antioxidant evaluation. After 2 and 4 weeks of use, skin tone and radiance increased and skin freckles decreased significantly. Under extremely cold and dry weather conditions, the use of the cream increased skin moisturization. CONCLUSIONS: The 3D ADMSC-CM cream evaluated in an environment similar to the human body was found to enhance skin whitening and moisturization and can therefore be used in the skin care and cosmetic industries as a biocosmetic product.

Effects of Allium hookeri Extracts on Hair-Inductive and Anti-Oxidative Properties in Human Dermal Papilla Cells.

Oxidative stress and cellular senescence in dermal papilla cells (DPCs) are major etiological factors causing hair loss. In this study, the effect of the Allium hookeri extract (AHE) on hair-inductive and anti-oxidative properties was investigated in human DPCs. As a result, it was found that a non-cytotoxic concentration of the extracts increased the viability and size of the human DPC spheroid, which was associated with the increased expression of hair-growth-related genes in cells. To determine whether or not these effects could be attributed to intracellular anti-oxidative effects, liquid chromatography-mass spectrometry alongside various biochemical analyses are conducted herein. An ingredient called alliin was identified as one of the main components. Furthermore, AHE treatment induced a significant decrease in H2O2-mediated cytotoxicities, cell death, and cellular senescence in human DPCs. Upon analyzing these results with a molecular mechanism approach, it was shown that AHE treatment increased ß-Catenin and NRF2 translocation into the nucleus while inhibiting the translocation of NF-κB (p50) through p38 and PKA-mediated phosphorylations of GSK3ß, an upstream regulator of those proteins. These results overall indicate the possibility that AHE can regulate GSK3ß-mediated ß-Catenin, NRF2, and NF-κB signaling to enhance hair-inductive properties and ultimately protect against oxidative stress-induced cellular damage in human DPCs.

Anti-Melanogenic Effects of Lilium lancifolium Root Extract via Downregulation of PKA/CREB and MAPK/CREB Signaling Pathways in B16F10 Cells.

Hyperpigmentation disorders causing emotional distress require the topical use of depigmenting agents of natural origin. In this study, the anti-melanogenic effects of the Lilium lancifolium root extract (LRE) were investigated in B16F10 cells. Consequently, a non-cytotoxic concentration of the extract reduced intracellular melanin content and tyrosinase activity in a dose-dependent manner, correlating with the diminished expression of core melanogenic enzymes within cells. LRE treatment also inhibited cyclic adenosine monophosphate (cAMP) response element-binding protein (CREB)/microphthalmia-associated transcription factor signaling, which regulates the expression of tyrosinase-related genes. Upon examining these findings from a molecular mechanism perspective, LRE treatment suppressed the phosphorylation of protein kinase A (PKA), p38, and extracellular signal-related kinase (ERK), which are upstream regulators of CREB. In addition, L-phenylalanine and regaloside A, specifically identified within the LRE using liquid chromatography-mass spectrometry, exhibited inhibitory effects on melanin production. Collectively, these results imply that LRE potentially suppresses cAMP-mediated melanogenesis by downregulating PKA/CREB and mitogen-activated protein kinase (MAPK)/CREB signaling pathways. Therefore, it can be employed as a novel therapeutic ingredient of natural origin to ameliorate hyperpigmentation disorders.

Identification of Loliolide with Anti-Aging Properties from Scenedesmus deserticola JD052.

Herein, different extracts of Scenedesmus deserticola JD052, a green microalga, were evaluated in vitro as a potential anti-aging bioagent. Although post-treatment of microalgal culture with either UV irradiation or high light illumination did not lead to a substantial difference in the effectiveness of microalgal extracts as a potential anti-UV agent, the results indicated the presence of a highly potent compound in ethyl acetate extract with more than 20% increase in the cellular viability of normal human dermal fibroblasts (nHDFs) compared with the negative control amended with DMSO. The subsequent fractionation of the ethyl acetate extract led to two bioactive fractions with high anti-UV property; one of the fractions was further separated down to a single compound. While electrospray ionization mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR) spectroscopy analysis identified this single compound as loliolide, its identification has been rarely reported in microalgae previously, prompting thorough systematic investigations into this novel compound for the nascent microalgal industry.