A physiologically-based pharmacokinetic model of oseltamivir phosphate and its carboxylate metabolite for rats and humans.

Oseltamivir phosphate (OP, Tamiflu®) is a widely used prodrug for the treatment of influenza viral infections. Orally administered OP is rapidly hydrolyzed by the carboxylesterases in animals to oseltamivir carboxylate (OC), a potent influenza virus neuraminidase inhibitor. The goals of this study were to develop and validate a physiologically-based pharmacokinetic (PBPK) model of OP/OC in rats and humans, and to predict the internal tissue doses for OP and OC in humans after receiving OP orally. To this end, a PBPK model of OP/OC was first developed in the rat, which was then scaled up to humans by replacing the physiological and biochemical parameters with human-specific values. The proposed PBPK model consisted of an OP and an OC sub-models each containing nine first-order, flow-limited tissue/organ compartments. OP metabolism to OC was assumed to carry out mainly by hepatic carboxylesterases although extra-hepatic metabolism also occurred especially in the plasma. The PBPK model was developed and validated by experimental data from our laboratories and from the literature. The proposed PBPK model accurately predicted the pharmacokinetic behavior of OP and OC in humans and rats after receiving a single or multiple doses of OP orally or an OC dose i.v. The PBPK model was used to predict the internal tissue doses of OP and OC in a hypothetical human after receiving the recommended dose of 75 mg/kg OP b.i.d. for 6 days. Steady-state OC concentrations in the plasma and major organs such as the lung and the brain were higher than the minimum in vitro IC50 reported for H1N1 influenza virus neuraminidase, confirming OP is an effective, anti-viral agent. OP side-effects in the gastrointestinal tract and brain of humans were explainable by the tissue doses found in these organs. The PBPK model provides a quantitative tool to evaluate the relationship between an externally applied dose of OP and the internal tissue doses in humans. As such the model can be used to adjust the dose regimens for adult patients in disease states e.g., renal failure and liver damage.

The Wnt modulator ICG­001 mediates the inhibition of nasopharyngeal carcinoma cell migration in vitro via the miR­150/CD44 axis.

The Wnt signaling pathway is known to serve an important role in the control of cell migration. The present study analyzed the mechanisms underlying the in vitro modulation of the migration of nasopharyngeal carcinoma (NPC) cells by the CREB­binding protein/catenin antagonist and Wnt modulator ICG­001. The results revealed that ICG­001­mediated inhibition of tumor cell migration involved downregulated mRNA and protein expression of the Wnt target gene cluster of differentiation (CD)44. It was also demonstrated that ICG­001 downregulated the expression of CD44, and this effect was accompanied by restored expression of microRNA (miRNA)­150 in various NPC cell lines. Using a CD44 3'­untranslated region luciferase reporter assay, miR­150 was confirmed to be a novel CD44­targeting miRNA, which could directly target CD44 and subsequently regulate the migration of NPC cells. The present study provides further insight into the inhibition of tumor cell migration through the modulation of miRNA expression by the Wnt modulator ICG­001.

Korean Red Ginseng extract induces angiogenesis through activation of glucocorticoid receptor.

BACKGROUND: Our previous studies have demonstrated that ginsenoside-Rg1 can promote angiogenesis in vitro and in vivo through activation of the glucocorticoid receptor (GR). Furthermore, microRNA (miRNA) expression profiling has shown that Rg1 can modulate the expression of a subset of miRNAs to induce angiogenesis. Moreover, Rb1 was shown to be antiangiogenic through activation of a different pathway. These studies highlight the important functions of miRNAs on ginseng-regulated physiological processes. The aim of this study was to determine the angiogenic properties of Korean Red Ginseng extract (KGE). METHODS AND RESULTS: Combining in vitro and in vivo data, KGE at 500 µg/mL was found to induce angiogenesis. According to the miRNA sequencing, 484 differentially expressed miRNAs were found to be affected by KGE. Among them, angiogenic-related miRNAs; miR-15b, -23a, -214, and -377 were suppressed by KGE. Meanwhile, their corresponding angiogenic proteins were stimulated, including vascular endothelial growth factor, vascular endothelial growth factor receptor-2, endothelial nitric oxide synthase, and MET transmembrane tyrosine kinase. The miRNAs-regulated signaling pathways of KGE were then found by Cignal 45-Pathway Reporter Array, proving that KGE could activate GR. CONCLUSION: KGE was found capable of inducing angiogenesis both in vivo and in vitro models through activating GR. This study provides a valuable insight into the angiogenic mechanisms depicted by KGE in relation to specific miRNAs.

MicroRNA profiling study reveals miR-150 in association with metastasis in nasopharyngeal carcinoma.

MicroRNAs (miRNAs) are small non-coding RNAs that play a crucial role in pathogenesis of human cancers. Several miRNAs have been shown to involve in nasopharyngeal carcinoma (NPC) pathogenesis through alteration of gene networks. A global view of the miRNA expression profile of clinical specimens would be the best way to screen out the possible miRNA candidates that may be involved in disease pathogenesis. In this study, we investigated the expression profiles of miRNA in formalin-fixed paraffin-embedded tissues from patients with undifferentiated NPC versus non-NPC controls using a miRNA real-time PCR platform, which covered a total of 95 cancer-related miRNAs. Hierarchical cluster analysis revealed that NPC and non-NPC controls were clearly segregated. Promisingly, 10 miRNA candidates were differentially expressed. Among them, 9 miRNAs were significantly up-regulated of which miR-205 and miR-196a showed the most up-regulated in NPC with the highest incidence percentage of 94.1% and 88.2%, respectively, while the unique down-regulated miR-150 was further validated in patient sera. Finally, the in vitro gain-of-function and loss-of-function assays revealed that miR-150 can modulate the epithelial-mesenchymal-transition property in NPC/HK-1 cells and led to the cell motility and invasion. miR-150 may be a potential biomarker for NPC and plays a critical role in NPC tumourigenesis.

Role of G3BP1 in glucocorticoid receptor-mediated microRNA-15b and microRNA-23a biogenesis in endothelial cells.

MicroRNAs (miRNAs) are a family of non-coding RNAs that play crucial roles in regulating various normal cellular responses. Recent studies revealed that the canonical miRNA biogenesis pathway is subject to sophisticated regulation. Hormonal control of miRNA biogenesis by androgen and estrogen has been demonstrated, but the direct effects of the glucocorticoid receptor (GR) on miRNA biogenesis are unknown. This study revealed the role of GR in miRNA maturation. We showed that two GR agonists, dexamethasone and ginsenoside-Rg1 rapidly suppressed the expression of mature miR-15b, miR-23a, and miR-214 in human endothelial cells. RNA pulldown coupled with proteomic analysis identified GTPase-activating protein (SH3 domain) binding protein 1 (G3BP1) as one of the RNA-binding proteins mediating GR-regulated miRNA maturation. Activated GR induced phosphorylation of v-AKT Murine Thymoma Viral Oncogene Homologue (AKT) kinase, which in turn phosphorylated and promoted nuclear translocation of G3BP1. The nuclear G3BP1 bound to the G3BP1 consensus sequence located on primary miR-15b~16-2 and miR-23a~27a~24-2 to inhibit their maturation. The findings from this study have advanced our understanding of the non-genomic effects of GR in the vascular system.

A Device for Performing Cell Migration/Wound Healing in a 96-Well Plate.

The cell migration/wounding assay is a commonly used method to study cell migration and other biological processes, such as angiogenesis and tumor metastasis. In this assay, cells are grown to form a confluent monolayer and a mechanical wound is created by scratching with a device. Then the migration rate of the cells towards the denuded area can be monitored by imaging. Our 8-channel mechanical wounder is designed to tackle most of the problems associated with the cell migration assay. Firstly, our wounder can be easily sterilized by autoclaving or with common disinfectants. Secondly, the individual adjustable pins allow even contact with the cell culture plate so that sharp and reproducible wounds can be created. Thirdly, the guiding bars on both sides of the wounder ensure consistent wounding position in each well. The use of disposable plastic pipette tips for wounding can further provide better handling of the wounder as well as to minimize cross-contamination. In conclusion, our cell wounder can provide researchers with a user friendly and reproducible device for performing the cell migration assay using the standard 96-well culture plate.

Role of microRNA-520h in 20(R)-ginsenoside-Rg3-mediated angiosuppression.

BACKGROUND: Ginsenoside-Rg3, the pharmacologically active component of red ginseng, has been found to inhibit tumor growth, invasion, metastasis, and angiogenesis in various cancer models. Previously, we found that 20(R)-ginsenoside-Rg3 (Rg3) could inhibit angiogenesis. Since microRNAs (miRNAs) have been shown to affect many biological processes, they might play an important role in ginsenoside-mediated angiomodulation. METHODS: In this study, we examined the underlying mechanisms of Rg3-induced angiosuppression through modulating the miRNA expression. In the miRNA-expression profiling analysis, six miRNAs and three miRNAs were found to be up- or down-regulated in vascular-endothelial-growth-factor-induced human-umbilical-vein endothelial cells (HUVECs) after Rg3 treatment, respectively. RESULTS: A computational prediction suggested that mature hsa-miR-520h (miR-520h) targets ephrin receptor (Eph) B2 and EphB4, and hence, affecting angiogenesis. The up-regulation of miR-520h after Rg3 treatment was validated by quantitative real-time polymerase chain reaction, while the protein expressions of EphB2 and EphB4 were found to decrease, respectively. The mimics and inhibitors of miR-520h were transfected into HUVECs and injected into zebra-fish embryos. The results showed that overexpression of miR-520h could significantly suppress the EphB2 and EphB4 protein expression, proliferation, and tubulogenesis of HUVECs, and the subintestinal-vessel formation of the zebra fish. CONCLUSION: These results might provide further information on the mechanism of Rg3-induced angiosuppression and the involvement of miRNAs in angiogenesis.

Anti-inflammatory effects of indirubin derivatives on influenza A virus-infected human pulmonary microvascular endothelial cells.

Influenza A virus (IAV) poses global threats to human health. Acute respiratory distress syndrome and multi-organ dysfunction are major complications in patients with severe influenza infection. This may be explained by the recent studies which highlighted the role of the pulmonary endothelium as the center of innate immune cells recruitment and excessive pro-inflammatory cytokines production. In this report, we examined the potential immunomodulatory effects of two indirubin derivatives, indirubin-3'-(2,3-dihydroxypropyl)-oximether (E804) and indirubin-3'-oxime (E231), on IAV (H9N2) infected-human pulmonary microvascular endothelial cells (HPMECs). Infection of H9N2 on HPMECs induced a high level of chemokines and cytokines production including IP-10, RANTES, IL-6, IFN-ß and IFN-γ1. Post-treatment of E804 or E231 could significantly suppress the production of these cytokines. H9N2 infection rapidly triggered the activation of innate immunity through phosphorylation of signaling molecules including mitogen-activated protein kinases (MAPKs) and signal transducer and activator of transcription (STAT) proteins. Using specific inhibitors or small-interfering RNA, we confirmed that indirubin derivatives can suppress H9N2-induced cytokines production through MAPKs and STAT3 signaling pathways. These results underscore the immunomodulatory effects of indirubin derivatives on pulmonary endothelium and its therapeutic potential on IAV-infection.

A Novel, Stable, Estradiol-Stimulating, Osteogenic Yam Protein with Potential for the Treatment of Menopausal Syndrome.

A novel protein, designated as DOI, isolated from the Chinese yam (Dioscorea opposita Thunb.) could be the first protein drug for the treatment of menopausal syndrome and an alternative to hormone replacement therapy (HRT), which is known to have undesirable side effects. DOI is an acid- and thermo-stable protein with a distinctive N-terminal sequence Gly-Ile-Gly-Lys-Ile-Thr-Thr-Tyr-Trp-Gly-Gln-Tyr-Ser-Asp-Glu-Pro-Ser-Leu-Thr-Glu. DOI was found to stimulate estradiol biosynthesis in rat ovarian granulosa cells; induce estradiol and progesterone secretion in 16- to 18-month-old female Sprague Dawley rats by upregulating expressions of follicle-stimulating hormone receptor and ovarian aromatase; counteract the progression of osteoporosis and augment bone mineral density; and improve cognitive functioning by upregulating protein expressions of brain-derived neurotrophic factor and TrkB receptors in the prefrontal cortex. Furthermore, DOI did not stimulate the proliferation of breast cancer and ovarian cancer cells, which suggest it could be a more efficacious and safer alternative to HRT.

Ginsenoside-Rg1 induces angiogenesis by the inverse regulation of MET tyrosine kinase receptor expression through miR-23a.

Therapeutic angiogenesis has been implicated in ischemic diseases and wound healing. Ginsenoside-Rg1 (Rg1), one of the most abundant active components of ginseng, has been demonstrated as an angiogenesis-stimulating compound in different models. There is increasing evidence implicating microRNAs (miRNAs), a group of non-coding RNAs, as important regulators of angiogenesis, but the role of microRNAs in Rg1-induced angiogenesis has not been fully explored. In this report, we found that stimulating endothelial cells with Rg1 could reduce miR-23a expression. In silico experiments predicted hepatocyte growth factor receptor (MET), a well-established mediator of angiogenesis, as the target of miR-23a. Transfection of the miR-23a precursor or inhibitor oligonucleotides validated the inverse relationship of miR-23a and MET expression. Luciferase reporter assays further confirmed the interaction between miR-23a and the MET mRNA 3'-UTR. Intriguingly, ginsenoside-Rg1 was found to increase MET protein expression in a time-dependent manner. We further demonstrated that ginsenoside-Rg1-induced angiogenic activities were indeed mediated through the down-regulation of miR-23a and subsequent up-regulation of MET protein expression, as confirmed by gain- and loss-of-function angiogenic experiments. In summary, our results demonstrated that ginsenoside-Rg1 could induce angiogenesis by the inverse regulation of MET tyrosine kinase receptor expression through miR-23a. This study has broadened our understanding of the non-genomic effects of ginsenoside-Rg1, and provided molecular evidence that warrant further development of natural compound as novel angiogenesis-promoting therapy.

Therapeutic targeting of CBP/ß-catenin signaling reduces cancer stem-like population and synergistically suppresses growth of EBV-positive nasopharyngeal carcinoma cells with cisplatin.

Nasopharyngeal carcinoma (NPC) is an EBV-associated epithelial malignancy prevalent in southern China. Presence of treatment-resistant cancer stem cells (CSC) may associate with tumor relapse and metastasis in NPC. ICG-001 is a specific CBP/ß-catenin antagonist that can block CBP/ß-catenin-mediated transcription of stem cell associated genes and enhance p300/ß-catenin-mediated transcription, thereby reducing the CSC-like population via forced differentiation. In this study, we aimed to evaluate the effect of ICG-001 on the CSC-like population, and the combination effect of ICG-001 with cisplatin in the C666-1 EBV-positive NPC cells. Results showed that ICG-001 inhibited C666-1 cell growth and reduced expression of CSC-associated proteins with altered expression of epithelial-mesenchymal transition (EMT) markers. ICG-001 also inhibited C666-1 tumor sphere formation, accompanied with reduced SOX2(hi)/CD44(hi) CSC-like population. ICG-001 was also found to restore the expression of a tumor suppressive microRNA-145 (miR-145). Ectopic expression of miR-145 effectively repressed SOX2 protein expression and inhibited tumor sphere formation. Combination of ICG-001 with cisplatin synergistically suppressed in vitro growth of C666-1 cells and significantly suppressed growth of NPC xenografts. These results suggested that therapeutically targeting of the CBP/ß-catenin signaling pathway with ICG-001 can effectively reduce the CSC-like population and combination with cisplatin can effectively suppress the growth of NPC.

Direct quantification of circulating miRNAs in different stages of nasopharyngeal cancerous serum samples in single molecule level with total internal reflection fluorescence microscopy.

MicroRNAs (miRNAs) are small noncoding RNAs that regulate human gene expression at the post-transcriptional level. Growing evidence indicates that the expression profile of miRNAs is highly correlated with the occurrence of human diseases including cancers. Playing important roles in complex gene regulation processes, the aberrant expression pattern of various miRNAs is implicated in different types and even stages of cancer. Besides localizing in cells, many of these miRNAs are found circulating around the body in a wide variety of fluids such as urine, serum and saliva. Surprisingly, these extracellular circulating miRNAs are highly stable and resistant to degradation, and therefore, are considered as promising biomarkers for early cancer diagnostic via noninvasive extraction from body fluids. Unfortunately, the abundance of these small RNAs is ultralow in the body fluids, making it challenging to quantify them in complex sample matrixes. Establishing a sensitive, specific yet simple assay for an accurate quantification of circulating miRNAs is therefore desirable. Our group previously reported a sensitive and specific detection assay of miRNAs in single molecule level with the aid of total internal reflection fluorescence microscopy. In this work, we advanced the assay to differentiate the expression of a nasopharyngeal carcinoma (NPC) up-regulator hsa-mir-205 (mir-205) in serum collected from patients of different stages of NPC. To overcome the background matrix interference in serum, a locked nucleic acid-modified molecular beacon (LNA/MB) was applied as the detection probe to hybridize, capture and detect target mir-205 in serum matrix with enhanced sensitivity and specificity. A detection limit of 500 fM was achieved. The as-developed method was capable of differentiating NPC stages by the level of mir-205 quantified in serum with only 10 µL of serum and the whole assay can be completed in 1 h. The experimental results agreed well with those previously reported whereas the quantity of miR-205 determined by our assay was found comparable to that of quantitative reverse transcription polymerase chain reaction (qRT-PCR), supporting that this assay can be served as a promising noninvasive detection tool for early NPC diagnosis, monitoring and staging.

Bioactive proteins and peptides isolated from Chinese medicines with pharmaceutical potential.

Some protein pharmaceuticals from Chinese medicine have been developed to treat cardiovascular diseases, genetic diseases, and cancer. Bioactive proteins with various pharmacological properties have been successfully isolated from animals such as Hirudo medicinalis (medicinal leech), Eisenia fetida (earthworm), and Mesobuthus martensii (Chinese scorpion), and from herbal medicines derived from species such as Cordyceps militaris, Ganoderma, Momordica cochinchinensis, Viscum album, Poria cocos, Senna obtusifolia, Panax notoginseng, Smilax glabra, Ginkgo biloba, Dioscorea batatas, and Trichosanthes kirilowii. This article reviews the isolation methods, molecular characteristics, bioactivities, pharmacological properties, and potential uses of bioactive proteins originating from these Chinese medicines.

Self-assembling protein platform for direct quantification of circulating microRNAs in serum with total internal reflection fluorescence microscopy.

MicroRNA (miRNA) has recently emerged as a new and important class of cellular regulators. Strong evidences showed that aberrant expression of miRNA is associated with a broad spectrum of human diseases, such as cancer, diabetes, cardiovascular and psychological disorders. However, the short length and low abundance of miRNA place great challenges for conventional techniques in the miRNA quantification and expression profiling. Here, we report a direct, specific and highly sensitive yet simple detection assay for miRNA without sample amplification. A self-assembled protein nanofibril acted as an online pre-concentrating sensor to detect the target miRNA. Locked nucleic acid (LNA) of complimentary sequence was served as the probe to capture the target miRNA analyte. The quantification was achieved by the fluorescence intensity measured with total internal reflection fluorescence microscopy. A detection limit of 1 pM was achieved with trace amount of sample consumption. This assay showed efficient single-base mismatch discrimination. The applicability of quantifying circulating mir-196a in both normal and cancer patient's serums was also demonstrated.

Ginsenoside compound K induces apoptosis in nasopharyngeal carcinoma cells via activation of apoptosis-inducing factor.

BACKGROUND: Nasopharyngeal carcinoma (NPC) has a high incidence rate in Southern China. Although there are conventional therapies, the side effects and toxicities are not always tolerable for patients. Recently, the tumoricidal effect of ginsenosides on different cancer cells has been studied. This study aims to investigate the anti-cancer effect of ginsenosides on NPC cells and their underlying mechanism. METHODS: The cytotoxicity of ginsenosides on NPC cell line HK-1 was measured by MTT assay. Apoptosis was detected by propidium iodide staining followed by flow cytometry. A xenograft tumor model was established by injecting nude mice with HK-1 cells. The activation of caspases and apoptosis-inducing factor (AIF) were evaluated by Western blot analysis. Nuclear translocation of AIF was also studied by immunofluorescence staining. Mitochondrial membrane potential was measured by JC-1 dye using flow cytometry. RESULTS: Four ginsenosides, 20 (S)-Rh2, compound K (CK), panaxadiol (PD) and protopanaxadiol (PPD), induced apoptotic cell death in HK-1 cells in a concentration-dependent manner. CK inhibited HK-1 xenograft tumor growth most extensively and depleted mitochondrial membrane potential depolarization and induced translocation of AIF from cytoplasm to nucleus in HK-1 cells. In addition, depletion of AIF by siRNA abolished CK-induced HK-1 cell death. CONCLUSION: Ginsenoside CK-induced apoptosis of HK-1 cells was mediated by the mitochondrial pathway and could significantly inhibit tumor growth in vivo.

Ginseng extracts restore high-glucose induced vascular dysfunctions by altering triglyceride metabolism and downregulation of atherosclerosis-related genes.

The king of herbs, Panax ginseng, has been used widely as a therapeutic agent vis-à-vis its active pharmacological and physiological effects. Based on Chinese pharmacopeia Ben Cao Gang Mu and various pieces of literature, Panax ginseng was believed to exert active vascular protective effects through its antiobesity and anti-inflammation properties. We investigated the vascular protective effects of ginseng by administrating ginseng extracts to rats after the induction of diabetes. We found that Panax ginseng can restore diabetes-induced impaired vasorelaxation and can reduce serum triglyceride but not cholesterol level in the diabetic rats. The ginseng extracts also suppressed the expression of atherosclerosis-related genes and altered the expression of lipid-related genes. The results provide evidence that Panax ginseng improves vascular dysfunction induced by diabetes and the protective effects may possibly be due to the downregulation of atherosclerosis-related genes and altered lipid metabolism, which help to restore normal endothelium functions.

A novel Hsp90 inhibitor AT13387 induces senescence in EBV-positive nasopharyngeal carcinoma cells and suppresses tumor formation.

BACKGROUND: Nasopharyngeal carcinoma (NPC) is an epithelial malignancy strongly associated with Epstein-Barr virus (EBV). AT13387 is a novel heat shock protein 90 (Hsp90) inhibitor, which inhibits the chaperone function of Hsp90 and reduces expression of Hsp90-dependent client oncoproteins. This study aimed to evaluate both the in vitro and in vivo antitumor effects of AT13387 in the EBV-positive NPC cell line C666-1. RESULTS: Our results showed that AT13387 inhibited C666-1 cell growth and induced cellular senescence with the downregulation of multiple Hsp90 client oncoproteins EGFR, AKT, CDK4, and restored the protein expression of negative cell cycle regulator p27. We also studied the ability of AT13387 to restore p27 expression by downregulation of AKT and the p27 ubiquitin mediator, Skp2, using AKT inhibitor and Skp2 siRNA. In the functional study, AT13387 inhibited cell migration with downregulation of a cell migration regulator, HDAC6, and increased the acetylation and stabilization of α-tubulin. We also examined the effect of AT13387 on putative cancer stem cells (CSC) by 3-D tumor sphere formation assay. AT13387 effectively reduced both the number and size of C666-1 tumor spheres with decreased expression of NPC CSC-like markers CD44 and SOX2. In the in vivo study, AT13387 significantly suppressed tumor formation in C666-1 NPC xenografts. CONCLUSION: AT13387 suppressed cell growth, cell migration, tumor sphere formation and induced cellular senescence on EBV-positive NPC cell line C666-1. Also, the antitumor effect of AT13387 was demonstrated in an in vivo model. This study provided experimental evidence for the preclinical value of using AT13387 as an effective antitumor agent in treatment of NPC.

Role of MIF/CXCL8/CXCR2 signaling in the growth of nasopharyngeal carcinoma tumor spheres.

Macrophage migration inhibitory factor (MIF) and CXCL8 (also named IL-8) are strongly expressed in the tissues of nasopharyngeal carcinoma (NPC). However, their role in the growth of NPC has not been fully examined. This study aims to evaluate the functions of MIF and CXCL8 on the growth of NPC tumor spheres. The elevated expression of CXCL8 in tumor over normal tissues was confirmed in 37 pairs of biopsies from NPC patients. In the in vitro study, all the poorly differentiated NPC cell lines, including the EBV-positive C666-1, and the EBV-negative CNE-1, CNE-2, SUNE-1, HNE-1 and HONE-1 cells, were found to express CXCL8 and MIF. Therefore, the EBV-positive C666-1 cell was selected to examine for the role of MIF and CXCL8 in the growth of the NPC tumor spheres. Functional study showed that the growth of C666-1 tumor spheres, under the nutrient poor or growth factor supplemented culture conditions, could be inhibited by the CXCL8 specific peptide inhibitor. The growth of the tumor spheres could also be reduced by the CXCR2 specific inhibitor SB225002 or the PI3K/AKT inhibitor LY294002, indicating that the endogenously produced CXCL8 plays an autocrine role in the growth of the tumor spheres. Further mechanistic studies revealed that the gene expression of CXCL8 could be reduced by the MIF specific small interfering RNA (siRNA) or NF-κB inhibitor parthenolide, and the growth of tumor spheres was also reduced after MIF siRNA transfection. Taken together, the present study highlights the role of MIF/CXCL8/CXCR2 axis in the growth of NPC tumor spheres. Chemotherapeutic interference of this signaling pathway may help to control the growth of the NPC tumor.

Ginsenoside Rb1 induces type I collagen expression through peroxisome proliferator-activated receptor-delta.

Wrinkle formation is one of the primary characteristics of skin aging, the major cause of wrinkle is the loss of structural protein type I collagen in dermal layer of skin. Topical application of natural substances to reduce wrinkle is gaining attention in recent years. Although a number of polyphenoic compounds are suggested to prevent ultraviolet-induced wrinkle, very few of them are able to increase type I collagen synthesis directly. Ginseng has been known in folk medicine of its beneficial effect to skin. The present study investigate the effect of ginsenoside on type I collagen induction in human dermal fibroblasts. Ginsenoside Rb1 was shown to induce type I collagen expression in dermal fibroblasts in a dose- and time-dependent manner. Recent studies suggest the important post-transcriptional regulatory role of microRNAs; here we demonstrated that miR-25 can directly inhibit type I collagen protein expression, and treatment of fibroblasts with Rb1 can reduce the inhibition by decreasing miR-25 level. Furthermore, we identified that the nuclear receptor, peroxisome proliferator-activated receptor-delta (PPARδ) is the key mediator of Rb1-induced type I collagen expression. Knockdown of PPARδ by small-interference RNA abolished the Rb1-induced type I collagen production and reversed the Rb1-suppressed miR-25 expression. These results demonstrated that ginsenoside Rb1 can increase target gene expression through transcriptional pathway, at the same time, inhibit the corresponding miRNA expression to minimize the translation repression. Furthermore, this study provide solid support of ginsenoside Rb1-induced type I collagen expression, which warrant further study in the dermatological application of ginsenosides in skin disorders.