Tubulosine selectively inhibits JAK3 signalling by binding to the ATP-binding site of the kinase of JAK3.

Gain- or loss-of-function mutations in Janus kinase 3 (JAK3) contribute to the pathogenesis of various haematopoietic malignancies and immune disorders, suggesting that aberrant JAK3 signalling is an attractive therapeutic target to treat these disorders. In this study, we performed structure-based computational database screening using the 3D structure of the JAK3 kinase domain and the National Cancer Institute diversity set and identified tubulosine as a novel JAK3 inhibitor. Tubulosine directly blocked the catalytic activity of JAK3 by selective interacting with the JAK3 kinase domain. Consistently, tubulosine potently inhibited persistently activated and interleukin-2-dependent JAK3, and JAK3-mediated downstream targets. Importantly, it did not affect the activity of other JAK family members, particularly prolactin-induced JAK2/signal transducer and activator of transcription 5 and interferon alpha-induced JAK1-TYK2/STAT1. Tubulosine specifically decreased survival and proliferation of cancer cells, in which persistently active JAK3 is expressed, by inducing apoptotic and necrotic/autophagic cell death without affecting other oncogenic signalling. Collectively, tubulosine is a potential small-molecule compound that selectively inhibits JAK3 activity, suggesting that it may serve as a promising therapeutic candidate for treating disorders caused by aberrant activation of JAK3 signalling.

Evaluation and Optimization of the Anti-Melanogenic Activity of 1-(2-Cyclohexylmethoxy-6-hydroxy-phenyl)-3-(4-hydroxymethyl-phenyl)-propenone Derivatives.

The chemical modification and optimization of biologically active compounds are essential steps in the identification of promising lead compounds for drug development. We previously reported the anti-melanogenic activity of 1-(2-cyclohexylmethoxy-6-hydroxy-phenyl)-3-(4-hydroxymethyl-phenyl)-propenone (chalcone 21). In this study, we synthesized 21 derivatives of chalcone 21 and evaluated their anti-melanogenic activity in -MSH-induced B16F10 cells. (E)-N-(4-(3-(2-(Cyclohexylmethoxy)phenyl)-3-oxoprop-1-en-1-yl)phenyl)acetamide (chalcone 21-21) exhibited the strongest inhibition of cellular melanin production, with an IC50 value of 0.54 M. It was more potent than chalcone 21 and the known anti-melanogenic agents kojic acid and arbutin, whose IC50 values were 4.9, 38.5, and 148.4 M, respectively. Chalcone 21-21 decreased the expression and activity of tyrosinase. It also decreased the expression of TRP1, TRP2 and MITF, the phosphorylation of CREB and ERK1/2, and the transcriptional activity of MITF and CRE. Our results demonstrate that chalcone-21-21 is an effective lead compound with anti-melanogenic activity.

6-Gingerol Suppresses Adipocyte-Derived Mediators of Inflammation In Vitro and in High-Fat Diet-Induced Obese Zebra Fish.

The present study was performed to investigate the molecular mechanism of 6-gingerol on adipocyte-mediated systemic inflammation in vitro and in high-fat diet-induced obese zebra fish. 6-Gingerol decreased adipogenesis due to the suppression of adipocyte differentiation markers, including peroxisome proliferator-activated receptor gamma, CCAATT enhancer binding protein α, and adipocyte protein 2, and triglyceride synthesis enzymes, including sterol regulatory element-binding protein-1, fatty acid synthase, lysophosphatidic acid acyltransferase, and acyl-coA : diacylglycerol acyltransferase 1, in 3T3-L1. A coculture insert system using 3T3-L1 with RAW 264.7 (coculture insert system using fully differentiated 3T3-L1 cells with RAW 264.7 macrophages) revealed that 6-gingerol increased anti-inflammatory cytokine interleukin-10. The expression of TNFα, monocyte chemotactic protein-1, interleukin-1ß, and interleukin-6 were decreased in the coculture insert system using fully differentiated 3T3-L1 cells with RAW 264.7 macrophages treated with 6-gingerol. Moreover, the coculture insert system using fully differentiated 3T3-L1 cells with RAW 264.7 macrophages treated with 6-gingerol inhibited the protein expression of TNFα and monocyte chemotactic protein-1 in RAW 264.7. 6-Gingerol decreased c-JUN N-terminal kinase and I kappa B kinase beta and its downstream target AP-1 expression in the coculture insert system using fully differentiated 3T3-L1 cells with RAW 264.7 macrophages. Furthermore, 6-gingerol decreased the expression of inducible nitric oxide synthase stimulated by the coculture insert system using fully differentiated 3T3-L1 cells with RAW 264.7 macrophages in RAW 264.7 and attenuated nitric oxide production in diet-induced obese zebra fish. Our results suggest that 6-gingerol suppresses inflammation through the regulation of the c-JUN N-terminal kinase-I kappa B kinase beta and its downstream targets.

Inhibition of tyrosinase activity and melanin production by the chalcone derivative 1-(2-cyclohexylmethoxy-6-hydroxy-phenyl)-3-(4-hydroxymethyl-phenyl)-propenone.

Abnormal accumulation of melanin pigments in the skin can be lead to hyperpigmentation disorders and melanoma. Melanin biosynthesis is ultimately regulated by the rate-limiting enzyme tyrosinase. In the present study, we synthesized chalcone derivatives and identified 1-(2-cyclohexylmethoxy-6-hydroxy-phenyl)-3-(4-hydroxymethyl-phenyl)-propenone (chalcone-21) as an anti-melanogenic substance in B16F10 melanoma cells. Chalcone-21 strongly inhibited cellular melanin production and tyrosinase activity in B16F10 melanoma cells stimulated with α-melanocyte stimulating hormone (α-MSH) or protoporphyrin IX. In addition, the compound suppressed not only the expression of tyrosinase, tyrosinase-related protein-1 (TRP-1), TRP-2, and microphthalmia-associated transcription factor (MITF), but also the transcriptional activity of tyrosinase and MITF. Our results demonstrated chalcone-21 to be an effective depigmenting agent.

Signal transducer and activator of transcription 3-mediated CD133 up-regulation contributes to promotion of hepatocellular carcinoma.

UNLABELLED: Enhanced expression of the cancer stem cell (CSC) marker, CD133, is closely associated with a higher rate of tumor formation and poor prognosis in hepatocellular carcinoma (HCC) patients. Despite its clinical significance, the molecular mechanism underlying the deregulation of CD133 during tumor progression remains to be clarified. Here, we report on a novel mechanism by which interleukin-6/signal transducer and activator of transcription 3 (IL-6/STAT3) signaling up-regulates expression of CD133 and promotes HCC progression. STAT3 activated by IL-6 rapidly bound to CD133 promoter and increased protein levels of CD133 in HCC cells. Reversely, in hypoxic conditions, RNA interference silencing of STAT3 resulted in decrease of CD133 levels, even in the presence of IL-6, with a concomitant decrease of hypoxia-inducible factor 1 alpha (HIF-1α) expression. Active STAT3 interacted with nuclear factor kappa B (NF-κB) p65 subunit to positively regulate the transcription of HIF-1α providing a mechanistic explanation on how those three oncogenes work together to increase the activity of CD133 in a hypoxic liver microenvironment. Activation of STAT3 and its consequent induction of HIF-1α and CD133 expression were not observed in Toll-like receptor 4/IL-6 double-knockout mice. Long-term silencing of CD133 by a lentiviral-based approach inhibited cancer cell-cycle progression and suppressed in vivo tumorigenicity by down-regulating expression of cytokinesis-related genes, such as TACC1, ACF7, and CKAP5. We also found that sorafenib and STAT3 inhibitor nifuroxazide inhibit HCC xenograft formation by blocking activation of STAT3 and expression of CD133 and HIF-1α proteins. CONCLUSION: IL-6/STAT3 signaling induces expression of CD133 through functional cooperation with NF-κB and HIF-1α during liver carcinogenesis. Targeting STAT3-mediated CD133 up-regulation may represent a novel, effective treatment by eradicating the liver tumor microenvironment.

Metformin enhances the anti-adipogenic effects of atorvastatin via modulation of STAT3 and TGF-ß/Smad3 signaling.

Adipocyte accumulation is associated with the development of obesity and obesity-related diseases. Interactions of master transcription factors and signaling cascades are required for adipogenesis. Regulation of excessive adipogenic processes may be an attractive therapeutic for treatment of obesity and obesity-related diseases. In this study, we found that atorvastatin exerts an anti-adipogenic activity in 3T3-L1 pre-adipocytes, and that this activity is elevated in combination with metformin. Expression of the adipogenic master regulators PPARγ and C/EBPα, and their target gene aP2, was suppressed by atorvastatin. Furthermore, atorvastatin treatment resulted in increased activation of the key master regulator of cellular energy homeostasis, AMPK. These biological activities of atorvastatin were elevated in combination with metformin. These anti-adipogenic activities were associated with regulation of the STAT3 and TGF-ß signaling cascades, resulting in the regulation of the expression of STAT3 target genes, such as KLF5, p53, and cyclin D1, and TGF-ß signaling inhibitory genes, such as SMAD7. Our results suggest that combination therapy with atorvastatin and metformin may have therapeutic potential for the treatment of obesity and obesity-related diseases caused by excessive adipogenesis.

Anti-angiogenic activity of thienopyridine derivative LCB03-0110 by targeting VEGFR-2 and JAK/STAT3 Signalling.

Vascular endothelial growth factor receptor-2 (VEGFR-2) and Janus kinase (JAK)/signal transducer and activator of transcription 3 (STAT3) signalling are important for tumor angiogenesis and metastasis. In this study, we identified (3-(2-(3-(morpholinomethyl)phenyl)thieno[3,2-b]pyridin-7-ylamino)phenol (LCB03-0110) as a potent angiogenesis inhibitor. LCB03-0110 inhibited VEGFR-2 and JAK/STAT3 signalling in primary cultured human endothelial cells and cancer cells. An in vitro kinase assay and molecular modelling revealed that LCB03-0110 inhibited VEGFR-2, c-SRC and TIE-2 kinase activity via preferential binding at the ATP-binding site of their kinases. LCB03-0110 successfully occupied the hydrophobic pocket of VEGFR-2, c-SRC and TIE-2. LCB03-0110 also inhibited hypoxia-induced HIF/STAT3 and EGF- or angiopoietin-induced signalling cascades. In addition, LCB03-0110 inhibited VEGF-induced proliferation, viability, migration and capillary-like tube formation. LCB03-0110 also suppressed the sprouting of endothelial cells in the rat aorta and the formation of new blood vessels in the mouse Matrigel plug assay, but also suppressed pulmonary metastasis and tumor xenograft in mice. Our results suggest that LCB03-0110 is a potential candidate small molecule for blocking angiogenesis mediated by aberrant activation of VEGFR-2 and JAK/STAT3 signalling.

Blockage of Stat3 enhances the sensitivity of NSCLC cells to PI3K/mTOR inhibition.

The PI3K/Akt/mTOR axis in lung cancer is frequently activated and implicated in tumorigenesis. Specific targeting of this pathway is therefore an attractive therapeutic approach for lung cancer. However, non-small cell lung cancer cells are resistant to BEZ235, a dual inhibitor of PI3K and mTOR. Interestingly, blockage of Stat3 with a selective inhibitor, S3I-201, or siRNA dramatically sensitized the BEZ235-induced cell death, as evident from increased PARP cleavage. Furthermore, inhibition of Stat3 led to enhancement of cell death induced by LY294002, a PI3K inhibitor. Treatment of cells with a combination of BEZ235 and S3I-201 significantly induced the proapoptotic transcription factor, CHOP, and its targets, Bim and DR4. Knockdown of CHOP or Bim suppressed cell death stimulated by the combination treatment, implicating the involvement of these BEZ235/S3I-201-induced factors in pronounced cell death. Moreover, the BEZ235/S3I-201 combination enhanced TRAIL-induced cell death. Our results collectively suggest that blockage of Stat3 presents an effective strategy to overcome resistance to PI3K/Akt/mTOR inhibition.

Chronic non-social stress affects depressive behaviors but not anxiety in mice.

The etiology of most psychiatric disorders is still incompletely understood. However, growing evidence suggests that stress is a potent environmental risk factor for depression and anxiety. In rodents, various stress paradigms have been developed, but psychosocial stress paradigms have received more attention than non-social stress paradigms because psychosocial stress is more prevalent in humans. Interestingly, some recent studies suggest that chronic psychosocial stress and social isolation affects mainly anxiety-related behaviors in mice. However, it is unclear whether chronic non-social stress induces both depression- and anxiety-related phenotypes or induces one specific phenotype in mice. In the present study, we examined the behavioral consequences of three chronic non-social stress paradigms: chronic predictable (restraint) stress (CPS), chronic unpredictable stress (CUS), and repeated corticosterone-HBC complex injection (RCI). Each of the three paradigms induced mild to severe depression/despair-like behaviors in mice and resulted in increased immobility in a tail suspension test. However, anxiety-related phenotypes, thigmotaxis and explorative behaviors, were not changed by the three paradigms. These results suggest that depression- and anxiety-related phenotypes can be dissociated in mouse stress models and that social and non-social stressors might affect brain circuits and behaviors differently.

BST-2 is a potential activator of invasion and migration in tamoxifen-resistant breast cancer cells.

Bone marrow stromal cell antigen 2 (BST-2) is a type II transmembrane protein that is known to be a therapeutic target in several types of cancer. However, despite its clinical importance, the roles of BST-2 expression have remained elusive. Here, we found that BST-2 expression is up-regulated in tamoxifen-resistant MCF-7 human breast cancer (TRM-7) cells, resulting in enhanced invasiveness and migration. Matrigel and wound healing assays also showed that overexpression of BST-2 increased invasion and migration in MCF-7 cells, whereas invasion and migration were decreased by the silencing of BST-2 in TRM-7 cells. In addition, B16F10 cells expressing BST-2 showed increased metastatic melanoma nodule growth in a lung metastasis mouse model. Furthermore, BST-2 expression and promoter activity were regulated by activated signal transducer and activator of transcription 3 (STAT3). Taken together, our results indicate that BST-2 is an important factor in the invasiveness and motility of tamoxifen-resistant breast cancer cells, and that its expression and activity are regulated by activated STAT3. Therefore, regulation of BST-2 is a potential therapeutic target for tamoxifen-resistant breast cancer.

Purple Corn Extract Improves Dry Eye Symptoms in Models Induced by Desiccating Stress and Extraorbital Lacrimal Gland Excision.

Dry eye disease (DED) occurs when there are not enough tears, and the associated symptoms-burns, itching, and a gritty feeling in the eye-can cause great discomfort. The purpose of this study was to evaluate the therapeutic effect of purple corn extract (PCE) on DED. Pretreatment with PCE prevented desiccation-stress-induced cell damage in human retinal pigment epithelial cells and primary human corneal epithelial cells. Furthermore, PCE reduced the mRNA expression of inflammatory mediators in the induction of desiccation stress. The therapeutic effects of PCE on DED were evaluated in an animal model with induced unilateral excision of the exorbital lacrimal gland. The administration of PCE was effective at recovering tear production, corneal surface irregularity, and conjunctival goblet cell density, as well as at reducing apoptotic cell death in the outer layer of the corneal epithelium. Collectively, PCE improved dry eye symptoms, and, therefore, it could be a potential agent to ameliorate and/or treat DED.

Development and applications of enzymatic modified starch with high water solubility providing a continuous supply of glucose.

Amylopectin clusters (APCs) are produced by cyclodextrin glucanotransferase (EC 2.4.1.19). Their solubility rate in aqueous solution was found to be 16.7 %. The weight-average molecular weight of APCs is ∼105 Da, as determined by multiangle laser light scattering analysis. Side chain length analysis indicated that the relative proportions of side chains with a degree of polymerization in the ranges of 2-8 and 25-50 decreased and increased, respectively, during preparation of APCs. In the exercise experiment, the blood glucose level of rats was higher in the APC-treated group than in the groups treated with commercial carbohydrate supplement (CCD) and glucose. In the forced swimming test, the swimming time in the APC and CCD groups increased by 22.6 % and 31.1 %, respectively, compared with the glucose administration group. The insulin levels were also similar between the APC and CCD groups. However, the glycogen levels in the liver and muscles of mice were significantly higher in the APC group than control group. These results suggest that APCs could potentially enhance endurance when added to sports drinks.

Heukharang lettuce (Lactuca sativa L.) leaf extract displays sleep-promoting effects through GABAA receptor.

ETHNOPHARMACOLOGICAL RELEVANCE: Although lettuce is traditionally known to have hypnotic and sedative effects, to date, only a few studies have documented its sleep-promoting effects and elucidated the related mechanisms. AIM OF THE STUDY: We aimed to investigate the sleep-promoting activity of Heukharang lettuce leaf extract (HLE) with increased lactucin content, known as a sleep-promoting substance in lettuce, in animal models. MATERIALS AND METHODS: To evaluate the effect of HLE on sleep behavior, analysis of electroencephalogram (EEG), gene expression of brain receptors, and activation mechanisms using antagonists were investigated in rodent models. RESULTS: High-performance liquid chromatography analysis showed that HLE contained lactucin (0.78 mg/g of extract) and quercetin-3-glucuronide (1.3 mg/g of extract). In the pentobarbital-induced sleep model, the group administered 150 mg/kg of HLE showed a 47.3% increase in sleep duration time as compared to the normal group (NOR). The EEG analysis showed that the HLE significantly increased non-rapid eye movement (NREM), where delta waves were improved by 59.5% when compared to the NOR, resulting in increased sleep time. In the caffeine-induced arousal model, HLE significantly decreased the awake time increased by caffeine administration (35.5%) and showed a similar level to NOR. In addition, HLE increased the gene and protein expression of gamma-aminobutyric acid receptor type A (GABAA), GABA type B, and 5-hydroxytryptamine (serotonin) receptor 1A. In particular, in comparison to the NOR, the group administered 150 mg/kg HLE showed an increase in expression levels of GABAA and protein by 2.3 and 2.5 times, respectively. When the expression levels were checked using GABAA receptor antagonists, HLE showed similar levels to NOR, as the sleep duration was reduced by flumazenil (45.1%), a benzodiazepine antagonist. CONCLUSIONS: HLE increased NREM sleep and significantly improved sleep behavior due to its action on the GABAA receptors. The collective findings suggest that HLE can be used as a novel sleep-enhancing agent in the pharmaceutical and food industries.

Purple Corn Extract Improves Benign Prostatic Hyperplasia by Regulating Prostate Cell Proliferation and Apoptosis.

Purple corn (Zea mays L.), utilized as a natural pigment in food production and processing, has been used to treat obesity, cystitis, and urinary tract infections. However, no reports of its use for benign prostatic hyperplasia (BPH) exist. Purple corn extract (PCE) contains anthocyanins, particularly cyanidin-3-O-glucoside, which have various pharmacological characteristics. Therefore, this study sought to elucidate the ameliorative effect of PCE on BPH in dihydrotestosterone (DHT)-stimulated WPMY-1 cells and testosterone propionate (TP)-induced rats. Expression levels of the upregulated androgen receptor (AR) and its related genes in DHT-stimulated WPMY-1 cells were reduced by PCE, and proapoptotic gene expression increased by modulating the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling cascade. PCE reduced the weight of the enlarged prostate by inhibiting the androgen/AR signaling-related markers. Histological variations in the prostate epithelium caused by TP injection were restored by PCE. Thus, PCE alleviates BPH by modulating prostate cell proliferation and apoptosis.

Squeaking sound in total hip arthroplasty using ceramic-on-ceramic bearing surfaces.

PURPOSE: To evaluate the causes and frequency of the squeaking sound in ceramic-on-ceramic THA. MATERIALS AND METHODS: This study included 61 hips of 50 patients who underwent ceramic-on-ceramic THA in our hospital from March 1999 to April 2005. The average age at the time of operation was 57.6 years. The average duration of follow-up was 69.5 months. Three different acetabular components were used: Osteonics (Stryker, USA: 24 cases), Bicontact (Aesculap, Germany: 27 cases) and ABG (Howmedica, UK: 10 cases). RESULTS: Fourteen (22.9%) of the 61 cases had a squeaking sound, and this sound started a mean of 47.57 months after the operation. Except in one case, the squeaking sound remained until the last follow-up. There was no difference in acetabular component position between the squeaking and nonsqueaking groups. The squeaking sound was found to be related to the BMI (body mass index) and cup design. It occurred frequently in patients with high BMI who had received a total hip arthroplasty using an Osteonics cup. Among 11 of the patients, squeaking occurred while squatting, and in 3 patients while walking. Six patients suffered from mild restrictions on their activities of daily living, and 8 had more than moderate restrictions with squeaking sounds. CONCLUSION: A squeaking sound in THA using ceramic-on-ceramic surfaces is not a rare complication, and often affects the patient's behavior.

Sophoricoside from Styphnolobium japonicum improves experimental atopic dermatitis in mice.

BACKGROUND: Abnormal immune responses, specifically excessive differentiation of Th2 cells, are associated with the development of atopic dermatitis (AD). Sophoricoside, the genistein-4'-ß-D-glucoside isolated from Styphnolobium japonicum, has previously demonstrated anti-inflammatory and immunosuppressive effects along with IL-3 and IL-5 inhibitory activities. Therefore, we speculated that sophoricoside could regulate AD by regulating abnormal immune responses. PURPOSE: To investigate the role of sophoricoside on AD-like allergic skin inflammation induced by ovalbumin (OVA) or 2,4,6-trinitrochlorobenzene (TNCB) in mouse models. METHODS: Sophoricoside was isolated from the 70% ethanol extract of S. japonicum dried mature seeds. After being submitted to a purification process, its purity was assessed by high-performance liquid chromatography (HPLC). The effects of sophoricoside were determined in vivo by OVA- and TNCB-induced AD-like allergic skin inflammation in mice. Skin tissues were subjected with hematoxylin-eosin (H&E), Giemsa and toluidine blue staining. In vitro CD4+ T cell differentiation was performed and the levels of serum immunoglobulins, cytokines, and genes related to CD4+ T cell differentiation were determined by enzyme-linked immunosorbent assay (ELISA) and quantitative real-time PCR. Cytokine bioassay, mixed lymphocytes reaction and cell viability assay were performed. RESULTS: Topical application of sophoricoside decreased the symptoms of AD-like allergic skin inflammation, including elevated hypertrophic scars with spongiotic epidermis, epidermal hyperplasia, hyperkeratosis, infiltration of immune, and mast cells, dermal thickness, amounts of immunoglobulins, and pro-inflammatory cytokines, and the mast cell population in the skin. Sophoricoside also decreased T cell antigen receptor (TCR)-mediated immune responses. In particular, sophoricoside suppressed the differentiation of naïve CD4+ T cells into Th cell subsets, including Th1, Th2, and Th17, by inhibiting the expression of their subset-specific master transcription factors, leading to suppression of the expression and production of these cell subset-specific cytokines. CONCLUSION: Sophoricoside can improve AD-like allergic skin diseases mainly by inhibiting pathogenic CD4+ T cell differentiation and immune responses.

Sophoricoside from Sophora japonica ameliorates allergic asthma by preventing mast cell activation and CD4+ T cell differentiation in ovalbumin-induced mice.

Asthma is a chronic inflammatory lung disorder with continuously increasing prevalence worldwide. Novel strategies are needed to prevent or improve asthma. The aim of this study was to investigate the effects of sophoricoside from Sophora japonica on allergic asthma. The mature seeds of S. japonica contain a large amount of sophoricoside. Sophoricoside reduced allergic and asthmatic symptoms by suppressing airway inflammation and antibody-antigen reaction in mouse models. In particular, sophoricoside suppressed immune cell recruitment into the airway lumens of the lungs and production of pro-inflammatory cytokines in the bronchoalveolar lavage fluid (BALF) of ovalbumin (OVA)-induced mice. It also decreased the amounts of histamine and arachidonic acid metabolites released in OVA-induced mice and antibody-antigen stimulated mast cells. In addition, sophoricoside decreased differentiation of naïve CD4+ T cells into T helper type 1 (Th1), Th2, and Th17 cells. Overall, we demonstrated that sophoricoside improved allergic asthma by suppressing mast cell activation and CD4+ T cell differentiation.

Effects of Astragalus Extract Mixture HT042 on Circulating IGF-1 Level and Growth Hormone Axis in Rats.

Astragalus extract mixture HT042 is a standardized functional food granted by the Korean FDA for promoting "Children's Height Growth". In this study, we determined whether HT042 affects circulatory Insulin-like growth factor-1 (IGF-1) after administration and investigated whether Growth hormone (GH), Growth hormone-releasing hormone receptor (GHRH-R), and Growth hormone secretagogue receptor (GHS-R) mRNAs are expressed in the pituitary, and whether Growth hormone-releasing hormone (GHRH) and Somatostatin (SST) are expressed in the hypothalamus. We also evaluated the growth effect of HT042 on endochondral bone formation. Male Sprague-Dawley rats in the control and HT042 groups were orally administered a single dose of the control and HT042, respectively, and those in the recombinant human GH (rhGH) group were subcutaneously injected with rhGH. Tetracycline was injected intraperitoneally 72 h prior to sacrifice to decide endochondral bone formation. To determine the endocrine or paracrine/autocrine mechanism, we evaluated the expression of local BMP-2 and IGF-1, an immunohistochemical study after HT042 administration. It was confirmed that the growth-promoting effect of HT042 can be contributed to the increase in serum IGF-1, which can be stimulated by GH secretion. Administration of HT042 modulated the activity of GHRH-R and GHR-S in the pituitary gland and promoted GH secretion, thereby changing longitudinal growth through GH/IGF-1 mediation. Results for GHRH and SST expression demonstrated that the hypothalamus can be influenced and mediated by HT042 through a complex neuroendocrine regulatory system. In addition, it was confirmed by oral administration for 10 days that HT042 increased bone formation in cartilage, which is important for height growth. The effect of HT042 could be owing to upregulation of local Bone morphogenetic protein-2 (BMP-2) and IGF-1 expression in the growth plate, which could be regarded as a GH-dependent autocrine/paracrine pathway, as well as circulatory IGF-1.

NSC114792, a novel small molecule identified through structure-based computational database screening, selectively inhibits JAK3.

BACKGROUND: Human or animals lacking either JAK3 or the common gamma chain (gammac) expression display severe combined immunodeficiency disease, indicating the crucial role of JAK3 in T-cell development and the homeostasis of the immune system. JAK3 has also been suggested to contribute to the pathogenesis of tumorigenesis. Recent studies identified activating JAK3 mutations in patients with various hematopoietic malignancies, including acute megakaryoblastic leukemia. Importantly, functional analyses of some of those JAK3 mutations have been shown to cause lethal hematopoietic malignancies in animal models. These observations make JAK3 an ideal therapeutic target for the treatment of various human diseases. To identify novel small molecule inhibitors of JAK3, we performed structure-based virtual screen using the 3D structure of JAK3 kinase domain and the NCI diversity set of compounds. RESULTS: We identified NSC114792 as a lead compound. This compound directly blocked the catalytic activity of JAK3 but not that of other JAK family members in vitro. In addition, treatment of 32D/IL-2Rbeta cells with the compound led to a block in IL-2-dependent activation of JAK3/STAT5 but not IL-3-dependent activation of JAK2/STAT5. Consistent with the specificity of NSC114792 for JAK3, it selectively inhibited persistently-activated JAK3, but failed to affect the activity of other JAK family members and other oncogenic kinases in various cancer cell lines. Finally, we showed that NSC114792 decreases cell viability by inducing apoptosis through down-regulating anti-apoptotic gene expression only in cancer cells harboring persistently-active JAK3. CONCLUSIONS: NSC114792 is a lead compound that selectively inhibits JAK3 activity. Therefore, our study suggests that this small molecule inhibitor of JAK3 can be used as a starting point to develop a new class of drugs targeting JAK3 activity, and may have therapeutic potential in various diseases that are caused by aberrant JAK3 activity.

MS-1020 is a novel small molecule that selectively inhibits JAK3 activity.

In order to identify Janus kinase/signal transducer and activator of transcription (JAK/STAT) signalling inhibitors, a cell-based high throughput screening was performed using a plant extract library that identified Nb-(alpha-hydroxynaphthoyl)serotonin called MS-1020 as a novel JAK3 inhibitor. MS-1020 potently inhibited persistently-active STAT3 in a cell type-specific manner. Further examination showed that MS-1020 selectively blocked constitutively-active JAK3 and consistently suppressed interleukin-2-induced JAK3/STAT5 signalling but not prolactin-induced JAK2/STAT5 signalling. Furthermore, MS-1020 affected cell viability only in cancer cells harbouring persistently-active JAK3/STATs, and in vitro kinase assays showed MS-1020 binds directly with JAK3, blocking its catalytic activity. Therefore, the present study suggested that this reagent selectively inhibits JAK3 and subsequently leads to a block in STAT signalling. Finally, MS-1020 decreased cell survival by inducing apoptosis via down-regulation of anti-apoptotic gene expression. These results suggest that MS-1020 may have therapeutic potential in the treatment of cancers harbouring aberrant JAK3 signalling.