The search for pyruvate kinase-R activators; from a HTS screening hit via an impurity to the discovery of a lead series.

Pyruvate kinase (PK) is an essential component of cellular metabolism, converting ADP and phosphoenolpyruvate (PEP) to pyruvate in the final step of glycolysis. Of the four unique isoforms of pyruvate kinase, R (PKR) is expressed exclusively in red blood cells and is a tetrameric enzyme that depends on fructose-1,6-bisphosphate (FBP) for activation. PKR deficiency leads to hemolysis of red blood cells resulting in anemia. Activation of PKR in both sickle cell disease and beta-thalassemia patients could lead to improved red blood cell fitness and survival. The discovery of a novel series of substituted urea PKR activators, via the serendipitous identification and diligent characterization of a minor impurity in an High Throughput Screening (HTS) hit will be discussed.

Physiologically Based Pharmacokinetic (PBPK) Modeling to Predict CYP3A-Mediated Drug Interaction between Saxagliptin and Nicardipine: Bridging Rat-to-Human Extrapolation.

The aim of this study was to predict the cytochrome P450 3A (CYP3A)-mediated drug-drug interactions (DDIs) between saxagliptin and nicardipine using a physiologically based pharmacokinetic (PBPK) model. Initially, in silico and in vitro parameters were gathered from experiments or the literature to construct PBPK models for each drug in rats. These models were integrated to predict the DDIs between saxagliptin, metabolized via CYP3A2, and nicardipine, exhibiting CYP3A inhibitory activity. The rat DDI PBPK model was completed by optimizing parameters using experimental rat plasma concentrations after co-administration of both drugs. Following co-administration in Sprague-Dawley rats, saxagliptin plasma concentration significantly increased, resulting in a 2.60-fold rise in AUC, accurately predicted by the rat PBPK model. Subsequently, the workflow of the rat PBPK model was applied to humans, creating a model capable of predicting DDIs between the two drugs in humans. Simulation from the human PBPK model indicated that nicardipine co-administration in humans resulted in a nearly unchanged AUC of saxagliptin, with an approximate 1.05-fold change, indicating no clinically significant changes and revealing a lack of direct translation of animal interaction results to humans. The animal-to-human PBPK model extrapolation used in this study could enhance the reliability of predicting drug interactions in clinical settings where DDI studies are challenging.

A long term study of the difference in efficacy and effect rate of various concentrations of retinol (1500-6600 IU) in middle aged women.

Retinol is widely used for topical application for antiaging. However, the efficacy and effect rate of different concentrations of retinol have been rarely analyzed. Therefore, in this study, the efficacy and rate of effect of retinol concentrations from 1500 to 6600 IU, on various skin parameters, have been compared. Seventy-two Korean women aged 40-59 years participated in this study. Retinol was used by them for 24 weeks; the effects were measured at 0, 2, 4, 8, 12, and 24 weeks. The measurement parameters for aging were crow's feet, forehead wrinkles, nasolabial fold, dermal density, and elasticity and that for skin color were skin brightness, yellowness, redness, and standard deviation of skin brightness. The texture of the skin was measured by measuring the skin roughness and pores, and the skin barrier function was evaluated through hydration, sebum, and desquamation. Low concentration retinol (1500-2500 IU) had a significantly higher effect in skin color, brightness, and elasticity and faster improvement rate in skin brightness and elasticity compared to that for high concentration (3300-6600 IU). High concentration of retinol had a significantly higher effect in wrinkles, dermal density and pores and faster improvement rate for wrinkles, skin texture, pores, and desquamation compared to that for low concentration. This study evaluated the changes caused by different concentration of retinol over a long period of time. The results of this study have great implications as the optimal concentration of retinol can be prescribed for an accurate period for the desired results without side effects.

Dynamic visualization of ultraviolet dose on skin with sunscreen applied using minimum erythema dose.

BACKGROUND: Visualizing the ultraviolet (UV) dose on skin serve as an intuitive approach to ensure appropriate sunscreen usage and reduce the risk of erythema. UV dose is determined by a number of external factors, such as properties of sunscreens, weather, and type of outdoor activity. We propose a framework for visualizing UV doses that considers various external factors. MATERIALS AND METHODS: First, the skin of a three-dimensional human model was represented using triangular meshes, and various static postures and dynamic motions were simulated to express outdoor activities. Then, we evaluated the persistency and insufficiency properties of sunscreen, which are time dependent and directly affect the effectiveness of the sunscreen skin protection factor (SPF) during UV exposure. Finally, to calculate the UV dose in real time, we tracked the trajectory of the sun and motion of the skin while considering the time-dependent properties of sunscreen. RESULTS: An S/W system was implemented based on the proposed framework to visualize the distribution of UV doses through dynamic color changes in exposed skin areas. The color types include true colors, which represent the minimum erythema dose (MED), and pseudo colors representing states before 1 MED is reached. We devised various examples to discuss the usability of the proposed framework. CONCLUSION: The system conveniently displays the MED according to an individual's skin phototype. When the properties of a wide range of commercial sunscreens are added to the system database, it is expected that the rate of appropriate sunscreen usage by customers will increase.

Skin biophysical properties including impaired skin barrier function determine ultraviolet sensitivity.

BACKGROUND: The levels of burning susceptibility to ultraviolet (UV) radiations are affected by various factors, including Fitzpatrick skin types, skin color, sex, and ethnicity. However, studies on the relationship between skin biophysical properties and erythemal responses to UV radiations are rare. OBJECTIVE: This study aimed to investigate biophysical properties of the skin that determined individual skin sensitivity to UV radiation. METHODS: As an indicator of skin sensitivity to UV radiation, Korean women were subjected to minimal erythema dose (MED) testing. The skin biophysical properties, such as skin hydration, transepidermal water loss (TEWL), were measured. MED were also evaluated in further variations in the skin, including barrier disruption. RESULTS: A significant negative correlation was observed between TEWL and MED. With an increase in TEWL, that represents reduced skin barrier function, skin UV sensitivity also increased. Artificial alteration of skin conditions also changed erythemal response to UV radiation. When the skin barrier was disrupted, MED significantly decreased, indicating increased skin UV sensitivity. It is hypothesized that the altered penetration of UV radiation into the stratum corneum under the respective skin conditions caused different erythema reactions. CONCLUSION: For the first time in a clinical study, the skin biophysical properties, including skin barrier function, were found to have significant effects on skin sensitivity to UV radiation. This finding could help predict individual susceptibility to UV damage. Therefore, skincare products that improve skin conditions associated with UV sensitivity, as well as sunscreen are important for protection against the hazards of UV radiation.

Comparison of Pharmacokinetics and Anti-Pulmonary Fibrosis-Related Effects of Sulforaphane and Sulforaphane N-acetylcysteine.

Sulforaphane (SFN), belonging to the isothiocyanate family, has received attention owing to its beneficial activities, including chemopreventive and antifibrotic effects. As sulforaphane N-acetylcysteine (SFN-NAC), a major sulforaphane metabolite, has presented similar pharmacological activities to those of SFN, it is crucial to simultaneously analyze the pharmacokinetics and activities of SFN and SFN-NAC, to comprehensively elucidate the efficacy of SFN-containing products. Accordingly, the anti-pulmonary fibrotic effects of SFN and SFN-NAC were assessed, with simultaneous evaluation of permeability, metabolic stability, and in vivo pharmacokinetics. Both SFN and SFN-NAC decreased the levels of transforming growth factor-ß1-induced fibronectin, alpha-smooth muscle actin, and collagen, which are major mediators of fibrosis, in MRC-5 fibroblast cells. Regarding pharmacokinetics, SFN and SFN-NAC were metabolically unstable, especially in the plasma. SFN-NAC degraded considerably faster than SFN in plasma, with SFN being formed from SFN-NAC. In rats, SFN and SFN-NAC showed a similar clearance when administered intravenously; however, SFN showed markedly superior absorption when administered orally. Although the plasma SFN-NAC concentration was low owing to poor absorption following oral administration, SFN-NAC was converted to SFN in vivo, as in plasma. Collectively, these data suggest that SFN-NAC could benefit a prodrug formulation strategy, possibly avoiding the gastrointestinal side effects of SFN, and with improved SFN-NAC absorption.

Layering sunscreen with facial makeup enhances its sun protection factor under real-use conditions.

BACKGROUND: The proper application of sunscreen is important to ensure protection of the skin against ultraviolet (UV) damage. Sunscreens are used in various ways in real world situations, which alters their UV protection efficacy. In this study, we simulated typical consumer use of sunscreen, which is often sequentially covered with facial makeup, in a laboratory study. METHODS: We compared the sun protection factors (SPF) of sunscreen and makeup products after consecutive layering of the products. RESULTS: The SPF of each sunscreen and makeup product was dramatically lower than stated on the label upon application of a typical amount used by a consumer, which is lower than recommended. For high-SPF products, the drop in effective protection was proportionally greater than those for the low-SPF products upon application of lower doses. However, layering sunscreen and makeup products greatly increased the effective SPF compared with that achieved by single application of each product, even when the amount of each product used was below the recommended level. CONCLUSION: Layering sunscreen with makeup may compensate for insufficient sunscreen application in real-life conditions by providing an additional source of UV protection and improving the homogeneity of coverage. Our results suggest that recommending consecutive application of sunscreen and makeup products may be a practical and useful approach to improving UV protection that would not require additional steps in the facial care routines of many individuals.

Development of 20(S)-Protopanaxadiol-Loaded SNEDDS Preconcentrate Using Comprehensive Phase Diagram for the Enhanced Dissolution and Oral Bioavailability.

In this study, we aimed to develop a 20(S)-protopanaxadiol (PPD)-loaded self-nanoemulsifying drug delivery system (SNEDDS) preconcentrate (PSP) using comprehensive ternary phase diagrams for enhanced solubility, physical stability, dissolution, and bioavailability. Capmul MCM C8 and Capryol 90 were selected as the oil phase owing to the high solubility of PPD in these vehicles (>15%, w/w). Novel comprehensive ternary phase diagrams composed of selected oil, surfactant, and PPD were constructed, and the solubility of PPD and particle size of vehicle was indicated on them for the effective determination of PSP. PSPs were confirmed via particle size distribution, physical stability, and scanning electron microscope (SEM) with the dispersion of water. The optimized PSP (CAPRYOL90/Kolliphor EL/PPD = 54/36/10, weight%) obtained from the six possible comprehensive ternary phase diagrams showed a uniform nanoemulsion with the particle size of 125.07 ± 12.56 nm without any PPD precipitation. The PSP showed a dissolution rate of 94.69 ± 2.51% in 60 min at pH 1.2, whereas raw PPD showed negligible dissolution. In oral pharmacokinetic studies, the PSP group showed significantly higher Cmax and AUCinf values (by 1.94- and 1.81-fold, respectively) than the raw PPD group (p < 0.05). In conclusion, the PSP formulation with outstanding solubilization, dissolution, and in-vivo oral bioavailability could be suggested using effective and comprehensive ternary phase diagrams.

Preparation and Characterization of Tenofovir Disoproxil-Loaded Enteric Microparticle.

Tenofovir disoproxil (TD) has narrow absorption site mostly in upper intestinal tract where tenofovir rapidly decomposes. The aim of this work was to prepare and evaluate tenofovir disoproxil-loaded enteric microparticles (TDEMs) for the enhanced duodenal delivery. TDEMs were composed of TD, eudragit L-100 (EL) and ethyl cellulose (EC) as release-controlling polymers. For the physicochemical characterization, TDEMs were evaluated in terms of encapsulation efficiency (EE%), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR). The dissolution test was also performed while continuously changing the medium pH. The EE% of TD in TDEMs was good and more than 90%. The EC and EL formed a physically mixed structure and maintained their respective properties in TDEMs as confirmed by SEM image and FT-IR analysis. Combination of EL and EC gave higher enteric properties to TDEMs than the single use of EL or EC. The optimized TDEM (TD/EL/EC = 0.2/1/1, w/w/w ratio) yielded mean dissolution rate less than 10% in 1 h at pH 1.2, but completed dissolution with a dissolution more than 85% within 1 h at pH 6.5. Thus, the suggested TDEM would be promising enteric microparticles for the intensive delivery of TD to the duodenum.

Optimization of Hydroxypropyl Methylcellulose and Dextrin in Development of Dried Nanosuspension for Poorly Water-Soluble Drug.

The purpose of this study is to identify the effects of a stabilizer and matrix former in the development of a celecoxib dried nanosuspension (DNS) for high dissolution rate and drug loading. Tween 80 and Hydroxypropyl Methylcellulose (HPMC) were used as stabilizers in the bead-milling process and dextrin was used as the matrix former in the spray-drying. Various nanosuspensions (NS) were prepared by varying the ratio of HPMC and dextrin, and the physicochemical properties of each formulation were evaluated for particle size, morphology, drug loading, crystallinity, redispersibility, physical stability and dissolution rate. HPMC efficiently stabilized the NS system and reduced the particle size of NS. The mean particle size of the NS with 0.5% HPMC (w/v) was the smallest (248 nm) of all formulations. Dextrin has been shown to inhibit the increase of particle size efficiently, which is known to occur frequently when NS is being solidified. As the dextrin increased in DNS, the dissolution rates of reconstituted NS were significantly improved. However, it was confirmed that more than the necessary amount of dextrin in DNS reduced the dissolution and drug loading. The dissolution of celecoxib in DNS prepared at the ratio (drug:dextrin, 1:2.5) was almost the highest. The dissolution of optimal formulation was 95.8% at 120 min, which was 2.0-fold higher than that of NS dried without dextrin. In conclusion, these results suggest that the formulation based on Tween 80, HPMC and dextrin may be an effective option for DNS to enhance its in vitro dissolution and in vivo oral absorption.

Evaluation of anisotropic properties of striae distensae with regard to skin surface texture and viscoelasticity.

BACKGROUND: Striae distensae (SD) are skin lesions of parallel streaks, which mostly occur during rapid tissue expansion. Considering the etiological mechanism of SD, including dermal network ruptures and alignment to mechanical stretch, structural directionality or anisotropy could be expected. Non-invasive objective methods for measuring the anisotropy of SD have not been suggested yet. Therefore, we evaluated the anisotropic properties of SD with regard to skin surface texture and viscoelasticity, to verify them as new objective evaluation parameters of SD. METHODS: Thirty-two healthy subjects with SD on their body participated. Anisotropy of skin surface texture and biomechanical properties of SD-involved skin and adjacent normal skin was assessed and compared. RESULTS: Analysis of skin surface texture, based on the ×60 magnified images, revealed that SD have more disordered patterns compared to the regular honeycomb patterns seen in the normal surrounding skin. SD have bigger sizes of each blob than normal skin. The overall anisotropy of skin texture was significantly higher in SD. Skin biomechanical parameters, measured using Cutiscan® , indicated the less deformable, less recovered, and less viscoelastic properties of SD. When comparing viscoelastic properties over 360°, SD were more anisotropic than the adjacent normal skin as well. CONCLUSION: We observed that SD were significantly more anisotropic than adjacent normal skin with regard to skin surface texture and viscoelasticity. Therefore, anisotropy could be an objective evaluation parameter to represent the distinctive features of SD. It can be applied for evaluation of the SD severity and clinical efficacy of various treatments.

Metabolic Stability of D-Allulose in Biorelevant Media and Hepatocytes: Comparison with Fructose and Erythritol.

D-allulose, a C-3 epimer of D-fructose, is a rare monosaccharide used as a food ingredient or a sweetener. In the present study, the in vitro metabolic stability of D-allulose was examined in biorelevant media, that is, simulated gastric fluid (SGF) and fasted state simulated intestinal fluid (FaSSIF) containing digestive enzymes, and in cryopreserved human and rat hepatocytes. The hepatocyte metabolic stabilities of D-allulose were also investigated and compared with those of fructose and erythritol (a sugar-alcohol with no calorific value). D-allulose was highly stable in SGF (97.8% remained after 60 min) and in FaSSIF (101.3% remained after 240 min), indicating it is neither pH-labile nor degraded in the gastrointestinal tract. D-allulose also exhibited high levels of stability in human and rat hepatocytes (94.5-96.8% remained after 240 min), whereas fructose was rapidly metabolized (43.1-52.6% remained), which suggested these two epimers are metabolized in completely different ways in the liver. The effects of D-allulose on glucose and fructose levels were negligible in hepatocytes. Erythritol was stable in human and rat hepatocytes (102.1-102.9% remained after 240 min). Intravenous pharmacokinetic studies in rats showed D-allulose was eliminated with a mean half-life of 72.2 min and a systemic clearance of 15.8 mL/min/kg. Taken together, our results indicate that D-allulose is not metabolized in the liver, and thus, unlikely to contribute to hepatic energy production.

Structures of full-length plasma kallikrein bound to highly specific inhibitors describe a new mode of targeted inhibition.

Plasma kallikrein (pKal) is a serine protease responsible for cleaving high-molecular-weight kininogen to produce the pro-inflammatory peptide, bradykinin. Unregulated pKal activity can lead to hereditary angioedema (HAE) following excess bradykinin release. HAE attacks can lead to a compromised airway that can be life threatening. As there are limited agents for prophylaxis of HAE attacks, there is a high unmet need for a therapeutic agent for regulating pKal with a high degree of specificity. Here we present crystal structures of both full-length and the protease domain of pKal, bound to two very distinct classes of small-molecule inhibitors: compound 1, and BCX4161. Both inhibitors demonstrate low nM inhibitory potency for pKal and varying specificity for related serine proteases. Compound 1 utilizes a surprising mode of interaction and upon binding results in a rearrangement of the binding pocket. Co-crystal structures of pKal describes why this class of small-molecule inhibitor is potent. Lack of conservation in surrounding residues explains the ∼10,000-fold specificity over structurally similar proteases, as shown by in vitro protease inhibition data. Structural information, combined with biochemical and enzymatic analyses, provides a novel scaffold for the design of targeted oral small molecule inhibitors of pKal for treatment of HAE and other diseases resulting from unregulated plasma kallikrein activity.

Preparation and Characterization of Celecoxib Nanosuspension Using Bead Milling.

The aim of this study is to develop nanosuspension for improved dissolution of poorly water-soluble celecoxib. We first prepared coarse suspension of celecoxib with Tween 80 and hydroxypropyl methylcellulose as stabilizers, and then fabricated nanosuspension using the bead milling technique. Depending on milling time, the physical properties of nanosuspension were evaluated by photon correlation spectroscopy (e.g., particle size and distribution) and scanning electron microscopy (SEM) (e.g., morphology). As results, the mean size of crystalline celecoxib particles was highly reduced (368.1±14.5 nm) as milling process proceeded comparing to celecoxib powder (6.5±1.0 µm). Morphology of milled celecoxib particles has changed considerably from bar-shape or plate-shape to needle-shape due to a high energy caused by milling. In the dissolution test, the celecoxib nanosuspension showed an improved dissolution profile at pH 1.2 compared to celecoxib powder (less than 1%). In contrast, 53.4% of celecoxib in nanosuspension was dissolved up to 30 minutes, demonstrating improved dissolution of celecoxib. Taken together, bead-milled nanosuspension could be an effective strategy that can improve the dissolution and bioavailability.

Flurbiprofen-Loaded Solid SNEDDS Preconcentrate for the Enhanced Solubility, In-Vitro Dissolution and Bioavailability in Rats.

The aim of this work was to prepare and optimize a solid self-nanoemulsifying drug delivery system pre-concentrate (SSP) containing water-insoluble flurbiprofen (FL) using a novel pseudo-ternary phase diagram. The pseudo-ternary phase diagram, composed of FL as the drug and dispersion core, Kollisolv MCT 70 as the oil phase, and TPGS (tocopherol polyethylene glycol 1000 succinate) as the surfactant, was constructed for the determination of the SSP region. SSP was investigated in terms of particle size, physical state by differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD), in vitro dissolution and oral pharmacokinetics in rats. The determined SSP (FL/Kollisolv MCT 70/TPGS = 10/10/80, weight %) in the pseudo-ternary phase diagram had the melting point of 32.37 °C and uniform mean particle size of below 30 nm without any precipitation of FL in the dispersion. In the dissolution test, the SSP exhibited 95.70 ± 3.40% of release at 15 min, whereas the raw FL showed poor dissolution (i.e., 6.75 ± 1.30%) at that time point. In addition, the SSP showed the enhanced oral absorption (i.e., 1.93-fold increase in AUCinfinite) as compared to the suspension group of raw FL. Therefore, the developed SSP would be a promising drug delivery system with excellent solubilization, dissolution, and bioavailability for FL.

Simultaneous Determination of Procainamide and N-acetylprocainamide in Rat Plasma by Ultra-High-Pressure Liquid Chromatography Coupled with a Diode Array Detector and Its Application to a Pharmacokinetic Study in Rats.

A simple, sensitive, and reliable reversed-phase, Ultra-High-Pressure Liquid Chromatography (UHPLC) coupled with a Diode Array Detector (DAD) method for the simultaneous determination of Procainamide (PA) and its major metabolite, N-acetylprocainamide (NAPA), in rat plasma was developed and validated. A simple deproteinization method with methanol was applied to the rat plasma samples, which were analyzed using UHPLC equipped with DAD at 280 nm, and a Synergi™ 4 µm polar, reversed-phase column using 1% acetic acid (pH 5.5) and methanol (76:24, v/v) as eluent in isocratic mode at a flow rate 0.2 mL/min. The method showed good linearity (r² > 0.998) over the concentration range of 20-100,000 and 20-10,000 ng/mL for PA and NAPA, respectively. Intra- and inter-day accuracies ranged from 97.7 to 110.9%, and precision was <10.5% for PA and 99.7 to 109.2 and <10.5%, respectively, for NAPA. The lower limit of quantification was 20 ng/mL for both compounds. This is the first report of the UHPLC-DAD bioanalytical method for simultaneous measurement of PA and NAPA. The most obvious advantage of this method over previously reported HPLC methods is that it requires small sample and injection volumes, with a straightforward, one-step sample preparation. It overcomes the limitations of previous methods, which use large sample volume and complex sample preparation. The devised method was successfully applied to the quantification of PA and NAPA after an intravenous bolus administration of 10 mg/kg procainamide hydrochloride to rats.

Discovery of a Novel Highly Selective Histamine H4 Receptor Antagonist for the Treatment of Atopic Dermatitis.

The histamine H4 receptor (H4R), a member of the G-protein coupled receptor family, has been considered as a potential therapeutic target for treating atopic dermatitis (AD). A large number of H4R antagonists have been disclosed, but no efficient agents controlling both pruritus and inflammation in AD have been developed yet. Here, we have discovered a novel class of orally available H4R antagonists showing strong anti-itching and anti-inflammation activity as well as excellent selectivity against off-targets. A pharmacophore-based virtual screening system constructed in-house successfully identified initial hit compound 9, and the subsequent homology model-guided optimization efficiently led us to discover pyrido[2,3- e]tetrazolo[1,5- a]pyrazine analogue 48 as a novel chemotype of a potent and highly selective H4R antagonist. Importantly, orally administered compound 48 exhibits remarkable efficacy on antipruritus and anti-inflammation with a favorable pharmacokinetic (PK) profile in several mouse models of AD. Thus, these data strongly suggest that our compound 48 is a promising clinical candidate for treatment of AD.

Effects of poloxamer 407-induced hyperlipidemia on hepatic multidrug resistance protein 2 (Mrp2/Abcc2) and the pharmacokinetics of mycophenolic acid in rats.

Hepatic multidrug resistance-associated protein 2 (Mrp2) is responsible for the majority of the biliary elimination of endogenous and exogenous substances, therefore it is important to evaluate possible functional changes in Mrp2 activity under conditions of hyperlipidemia (HL). Thus, the present study assessed the protein expression and transporting activity of hepatic Mrp2 based on the in vivo biliary excretion of phenolsulfonphthalein (PSP) as a model anionic substrate for Mrp2 in poloxamer 407-induced hyperlipidemic rats (HL rats) and compared these values with those for control rats. The pharmacokinetics of mycophenolic acid (MPA) and mycophenolic acid-7-O-glucuronide (MPAG) were evaluated after the intravenous (5 mg/kg) and oral (10 mg/kg) administration of MPA to control and HL rats. In HL rats, the protein expression of hepatic Mrp2 and its biliary transporting activity exhibited significant reductions (by 24.3% and 24.6%, respectively) in the absence of a change in bile flow rate. Unexpectedly, HL and control rats showed comparable biliary excretion rates of MPAG due to the counter effects of the reduced expression and activity of Mrp2 and a 484% increase in the free fraction of MPAG in HL rats. The estimated biliary clearance value of free MPAG in HL rats was considerably slower (by 77.1%) than that in control rats. Although significant pharmacokinetic changes in total MPA and MPAG levels were not observed in HL rats, there was a marked increase in free MPA and MPAG levels. Clinically relevant pharmacokinetic changes in subjects with HL that are related to MRP2 could not be ruled out. Copyright © 2016 John Wiley & Sons, Ltd.

Pomolic acid inhibits metastasis of HER2 overexpressing breast cancer cells through inactivation of the ERK pathway.

Expression of the CXC chemokine receptor-4 (CXCR4), a G protein-coupled receptor, and HER2, a receptor tyrosine kinase, strongly correlates with tumor progression and metastatic potential of breast cancer cells. We report the identification of pomolic acid (PA) as a novel regulator of HER2 and CXCR4 expression. We found that PA downregulated the expression of HER2 and CXCR4 in SKBR3 cells in a dose- and time-dependent manner. When investigated for the molecular mechanism(s), it was found that the downregulation of HER2 and CXCR4 was not due to proteolytic degradation but rather to transcriptional regulation as indicated by downregulation of mRNA expression. Moreover, we show that PA inhibits phosphorylation of ERK and reduces NF-κB activation. Suppression of CXCR4 expression by PA correlated with the inhibition of CXCL12-induced invasion of HER2-overexpressing breast cancer cells. Overall, our results demonstrate for the first time that PA is a novel inhibitor of HER2 and CXCR4 expression via kinase pathways and may play a critical role in determining the metastatic potential of breast cancer cells.

Hispolon from Phellinus linteus induces apoptosis and sensitizes human cancer cells to the tumor necrosis factor-related apoptosis-inducing ligand through upregulation of death receptors.

The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a potent anticancer agent possessing the ability to induce apoptosis in various cancer cells but not in non­malignant cells. However, certain type of cancer cells are resistant to TRAIL­induced apoptosis and some acquire resistance after the first treatment. So development of an agent that can reduce or avoid resistance in TRAIL­induced apoptosis has garnered significant attention. The present study evaluated the anticancer potential of hispolon in TRAIL­induced apoptosis and indicated hispolon can sensitize cancer cells to TRAIL. As the mechanism of action was examined, hispolon was found to activate caspase­3, caspase­8 and caspase­9, while downregulating the expression of cell survival proteins such as cFLIP, Bcl­2 and Bcl­xL and upregulating the expression of Bax and truncated Bid. We also found hispolon induced death receptors in a non­cell type­specific manner. Upregulation of death receptors by hispolon was found to be p53-independent but linked to the induction of CAAT enhancer binding protein homologous protein (CHOP). Overall, hispolon was demonstrated to potentiate the apoptotic effects of TRAIL through downregulation of anti­apoptotic proteins and upregulation of death receptors linked with CHOP and pERK elevation.