Effect of Denosumab on the Change of Osteoclast Precursors Compared to Zoledronate Treatment in Postmenopausal Women with Osteoporosis

Background@#A rapid increase in bone turnover and bone loss has been observed in response to the discontinuation of denosumab. It led to an acute increase in the fracture risk, similar to that observed in the untreated patients. We aimed to investigate the effect of denosumab on osteoclast (OC) precursor cells compared to that of zoledronate. @*Methods@#The study compared the effects of denosumab (60 mg/24-week) and zoledronate (5 mg/48-week) over 48 weeks in postmenopausal women with osteoporosis. From patients’ peripheral mononuclear cells, CD14+/CD11b+/vitronectin receptor (VNR)- and CD14+/CD11b+/VNR+ cells were isolated using fluorescent-activated cell sorting, representing early and late OC precursors, respectively. The primary endpoint was the changes in OC precursors after 48 weeks of treatment. @*Results@#Among the 23 patients, 11 were assigned to the denosumab group and 12 to the zoledronate group (mean age, 69 years). After 48 weeks, the changes in OC precursors were similar between and within the groups. Serum C-terminal telopeptide of type I collagen levels were inversely correlated with OC precursor levels after denosumab treatment (r=-0.72, P<0.001). Lumbar spine, femur neck, and total hip bone mineral density (BMD) increased in both groups. Lumbar spine BMD increased more significantly in the denosumab group than in the zoledronate group. @*Conclusions@#Denosumab and zoledronate treatments induced similar changes in OC precursors. During denosumab treatment, old age and suppressed bone turnover were associated with increased OC precursor cell populations. Further validation studies with prospective designs are required.

Anticancer Activity of Tubulosine through Suppression of Interleukin-6-Induced Janus Kinase 2/Signal Transducer and Activation of Transcription 3 Signaling / 한국유방암학회지

PURPOSE: The chemical structure of tubulosine has been known since the mid-1960s. However, little is known about its biological and pharmacological functions. The aim of this study was to investigate the novel functions of tubulosine in cancer treatment, specifically in breast cancer. METHODS: An Unpaired (Upd)-induced Drosophila cell line and interleukin (IL)-6-stimulated human breast cancer cell lines were used to investigate the biological and pharmacological activities of tubulosine in vitro. To investigate the activities of tubulosine, we performed molecular and cellular experiments such as Western blot and reverse transcription polymerase chain reaction analyses, immunoprecipitation and terminal deoxynucleotidyl transferase dUTP nick end labeling assays, and immunofluorescence staining using breast cancer cell lines. RESULTS: Tubulosine exhibited anticancer activity in IL-6-stimulated human breast cancer cells. Moreover, tubulosine reduced the tyrosine phosphorylation level and transcriptional activity of signal transducer and activator of transcription (STAT) protein at 92E in Upd-induced Drosophila cells. Additionally, tubulosine suppressed IL-6-induced Janus kinase 2 (JAK2)/STAT3 signaling, resulting in decreased viability and induction of apoptotic cell death in breast cancer cells. Interestingly, inhibition of IL-6-induced JAK2/STAT3 signaling by tubulosine was associated with the blocking of IL-6 receptor (IL-6R) and glycoprotein 130 (gp130) binding. CONCLUSION: Tubulosine exhibits anticancer activity through functional inhibition of IL-6-induced JAK2/STAT3 signaling by targeting IL-6Rα/gp130 binding in breast cancer cells. These findings suggest that tubulosine may hold promise for the treatment of inflammation-associated cancers, including breast cancer.

T Cell-Specific Knockout of STAT3 Ameliorates Dextran Sulfate Sodium-Induced Colitis by Reducing the Inflammatory Response

Signal transducer and activator of transcription 3 (STAT3) has a crucial role in various autoimmune disorders including, inflammatory bowel disease (IBD). Our previous study demonstrated that STAT3 activation by IL-6 in colonic epithelial cells exacerbates experimental ulcerative colitis. Activated T lymphocytes are also found in ulcerative colitis patients with intestinal inflammation, but the role of STAT3 in T cells remains elusive. To determine the STAT3 function of T cells in intestinal inflammation, we generated T cell-specific STAT3 knockout (KO) mice and used dextran sulfate sodium (DSS) to induce colitis. In this study, we demonstrated that T cell-specific STAT3 deletion alleviated DSS-induced colitis in mice, resulting in reduced histological scores and myeloperoxidase (MPO) activity. Importantly, the population of T cells in the spleen and lymph nodes was significantly decreased in the control and DSS-induced groups of STAT3 KO mice. In addition, STAT3 deficiency in T cells markedly reduced the production of interferon (IFN)-γ, IL-6, and IL-17A, whereas IL-10 secretion was increased. Collectively, the results suggest that STAT3 in T cells may be a therapeutic target in ulcerative colitis by balancing the immune response through T cell homeostasis.

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.

Benzoxathiol derivative BOT-4-one suppresses L540 lymphoma cell survival and proliferation via inhibition of JAK3/STAT3 signaling

Persistently activated JAK/STAT3 signaling pathway plays a pivotal role in various human cancers including major carcinomas and hematologic tumors, and is implicated in cancer cell survival and proliferation. Therefore, inhibition of JAK/STAT3 signaling may be a clinical application in cancer therapy. Here, we report that 2-cyclohexylimino-6-methyl-6,7-dihydro-5H-benzo [1,3]oxathiol-4-one (BOT-4-one), a small molecule inhibitor of JAK/STAT3 signaling, induces apoptosis through inhibition of STAT3 activation. BOT-4-one suppressed cytokine (upd)-induced tyrosine phosphorylation and transcriptional activity of STAT92E, the sole Drosophila STAT homolog. Consequently, BOT-4-one significantly inhibited STAT3 tyrosine phosphorylation and expression of STAT3 downstream target gene SOCS3 in various human cancer cell lines, and its effect was more potent in JAK3-activated Hodgkin's lymphoma cell line than in JAK2-activated breast cancer and prostate cancer cell lines. In addition, BOT-4-one-treated Hodgkin's lymphoma cells showed decreased cell survival and proliferation by inducing apoptosis through down-regulation of STAT3 downstream target anti-apoptotic gene expression. These results suggest that BOT-4-one is a novel small molecule inhibitor of JAK3/STAT3 signaling and may have therapeutic potential in the treatment of human cancers harboring aberrant JAK3/STAT3 signaling, specifically Hodgkin's lymphoma.

STAT3 inhibits the degradation of HIF-1alpha by pVHL-mediated ubiquitination

Hypoxia-inducible factor 1alpha (HIF-1alpha) is rapidly degraded by the ubiquitin-proteasome pathway under normoxic conditions. Ubiquitination of HIF-1alpha is mediated by interaction with von Hippel-Lindau tumor suppressor protein (pVHL). In our previous report, we found that hypoxia-induced active signal transducer and activator of transcription3 (STAT3) accelerated the accumulation of HIF-1alpha protein and prolonged its half-life in solid tumor cells. However, its specific mechanisms are not fully understood. Thus, we examined the role of STAT3 in the mechanism of pVHL-mediated HIF-1alpha stability. We found that STAT3 interacts with C-terminal domain of HIF-1alpha and stabilizes HIF-1alpha by inhibition of pVHL binding to HIF-1alpha. The binding between HIF-1alpha and pVHL, negative regulator of HIF-1alpha stability, was interfered dose-dependently by overexpressed constitutive active STAT3. Moreover, we found that the enhanced HIF-1alpha protein levels by active STAT3 are due to decrease of poly-ubiquitination of HIF-1alpha protein via inhibition of interaction between pVHL and HIF-1alpha. Taken together, our results suggest that STAT3 decreases the pVHL-mediated ubiquitination of HIF-1alpha through competition with pVHL for binding to HIF-1alpha, and then stabilizes HIF-1alpha protein levels.

LYR71, a derivative of trimeric resveratrol, inhibits tumorigenesis by blocking STAT3-mediated matrix metalloproteinase 9 expression

Tumor migration/invasion is the main cause of tumor progression and STAT3 is needed to enhance tumor migration/invasion by up-regulating MMP-9. Thus, agents that inhibit STAT3 activation may be used as an anticancer drug. We present herein that 6-methyl-2-propylimino-6, 7-dihydro-5H-benzo [1, 3]-oxathiol- 4-one (LYR71) , a derivative of trimeric resveratrol, has an anticancer activity through inhibition of STAT3 activation. We found that LYR71 suppressed STAT3 activation and inhibited the expression and activity of MMP-9 in RANTES-stimulated breast cancer cells. In addition, LYR71 reduced RANTES-induced MMP-9 transcripts by blocking STAT3 recruitment, dissociating p300 and deacetylating histone H3 and H4 on the MMP-9 promoter. Furthermore, LYR71 inhibited tumor migration/invasion in RANTES-treated breast cancer cells and consequently blocked tumor progression in tumor-bearing mice. Taken together, the results of this study suggest that LYR71 can be therapeutically useful due to the inhibition effect of STAT3-mediated MMP-9 expression in breast cancer cells.

Comparison of anti-oxidant activities of seventy herbs that have been used in Korean traditional medicine

Many herbs have been used as therapeutics in Korean traditional medicine. In view of their clinical indications, anti-oxidant activity may contribute to their pharmacological effects. However, anti-oxidant information on these plants has not been available. In this study, seventy herbs which have been used in Korean traditional medicine were selected and screened for anti-oxidant activity using their water extracts. The anti-oxidant activity was assessed by their ability to inhibit three oxidation reactions; luminol/Fenton reagent, 2, 7-dichlorodihydrofluorescein (DCHF)/Fenton reagent and DCHF/peroxynitrite. In each assay, 70 herbs were divided into two groups; anti-oxidant group which inhibited the respective oxidation reaction and was majority (about 60 herbs), and pro-oxidant group which enhanced the oxidation reaction but was minority (more or less 10 herbs). When the herbs were listed in the order of their anti-oxidant strength, the orders obtained from each assay were found to be quite similar. The upper top rankers (more or less 10 herbs) in each assay showed strong activity compared to the others. The uppermost rankers in each assay were Rubus coreanus Miquel/ Rubus schizostylus, Schisandra chinensis Baillon/ Schizandra chinensis and Terminalia chebula Retzius/ Terminalia chebula. Of the pro-oxidant herbs, about 4-5 herbs were strongly pro-oxidant, which enhanced the control oxidation reactions to 150-300%. But the meaning of this observation is not known since few of them in one assay were also anti-oxidant in other assays. The results obtained in the present study may serve as information for understanding pharmacological effects of these herbs and developing new drugs from them.

Anti-inflammatory effects of 8-hydroxydeoxyguanosine in LPS-induced microglia activation: suppression of STAT3-mediated intercellular adhesion molecule-1 expression

To elucidate the roles of 8-hydroxydeoxyguanosine (oh8dG), the nucleoside of 8-hydroxyguanine (oh8Gua), we examined the effects of oh8dG upon LPS-induced intercellular adhesion molecule-1 (ICAM-1) expression and the underlying mechanisms in brain microglial cells. We found that oh8dG reduces LPS-induced reactive oxygen species (ROS) production, STAT3 activation, and ICAM-1 expression. oh8dG also suppresses pro-inflammatory cytokines, such as TNF-alpha, IL-6 and IFN-gamma. Overexpression of dominant negative STAT3 completely diminshed STAT3-mediated ICAM-1 transcriptional activity. Chromatin immunoprecipitation studies revealed that oh8dG inhibited recruitment of STAT3 to the ICAM-1 promoter, followed by a decrease in ICAM-1 expression. Using mice lacking a functional Toll-like receptor 4 (TLR4), we demonstrated that, while TLR4+/+ microglia were activated by LPS, TLR4-/-microglia exhibited inactivated STAT3 in response to LPS. Evidently, LPS modulates STAT3-dependent ICAM-1 induction through TLR4-mdiated cellular responses. Oh8dG apparently plays a role in anti-inflammatory actions via suppression of ICAM-1 gene expression by blockade of the TLR4-STAT3 signal cascade in inflammation-enhanced brain microglia. Therefore, oh8dG in the cytosol probably functions as an anti-inflammatory molecule and should be considered as a candidate for development of anti-inflammatory agents.

Hypoxia activates the cyclin D1 promoter via the Jak2/STAT5b pathway in breast cancer cells

Hypoxia, a common consequence of solid tumor growth in breast cancer or other cancers, serves to propagate a cascade of molecular pathways which include angiogenesis, glycolysis, and various cellcycle control proteins. As we have shown previously, hypoxia activates STAT5 (signal transducer and activator of transcription 5) and increases its binding activity to the GAS element in mammary epithelial cells. In this study we attempted to elucidate the mechanism by which cyclin D1 is regulated by the STAT5 protein under hypoxic conditions. Our data demonstrate that hypoxia (2% O2) or desferrioxamine (DFO) induces tyrosine and serine phosphorylation of STAT5 in human breast cancer cells (MCF-7) and mammary epithelial cells (HC11). Imunoprecipitation and subsequent Western analysis showed that Jak2 leads to the tyrosine phosphorylation and activation of STAT5a or STAT5b under hypoxic conditions. Using a transfected COS-7 cell model system, we demonstrate that the activity of a cyclin D1 promoter-luciferase construct increased under hypoxic conditions or DFO treatment. The activity of the STAT5b/cyclin D1 promoter increased significantly by 12 h of hypoxia, whereas the activity of the STAT5a/cyclin D1 promoter was unaffected under hypoxic conditions. These increases in promoter activity are predominantly mediated by the Jak2/ STAT5b signaling pathway. We have shown by EMSA that hypoxia induces STAT5 to bind to the cyclin D1 promoter (GAS-1) in MCF-7 and HC11 cells. These data suggest that STAT5b may mediate the transcriptional activation of cyclin D1 after hypoxic stimulation.

Interleukin-7 Receptor is Indispensable for Proliferation and Survival in Thymic gamma sigma T Cell Development

BACKGROUND: Interleukin-7 receptor (IL-7R) alpha-deficient mice have small numbers of B cells and alpha beta T cells in periphery, they totally lack gamma sigma T cells. In addition, the V-J recombination and transcription of TCRgamma genes is also severely impaired in IL-7Ralpha-deficient mice. Stat5, a signaling molecule of the IL-7R, induces germline transcription in the TCRgamma locus, and promotes V-J recombination and gamma sigma T cell development. However, the roles for IL-7R signaling pathway in thymic or extrathymic gamma sigma T cell development are largely unknown. METHODS: To clarify the role of the IL-7 receptor in proliferation and survival of gamma sigma T cells, we introduced the TCR gamma sigma transgene, Vgamma2/ Vsigma5, into IL-7Ralpha-deficient mice, and investigated the development of gamma sigma T cells. RESULTS: We found that Vgamma2/Vsigma5 transgene restored gamma sigma T cells in the epithelium of the small intestine (IEL) but not in the thymus and the spleen. Further addition of a bcl-2 transgene resulted in partial recovery of gamma sigma T cells in the thymus and the spleen of these mice. CONCLUSION: Taken together, this study revealed that the IL-7Ralpha is indispensable for proliferation and survival mainly in thymic gamma sigma T cell development.

Hypoxia activates signal transducers and activators of transcription 5 (STAT5) and increases its binding activity to the GAS element in mammary epithelial cells

STATs (signal transducers and activators of transcription) are proteins with dual functions: signal transducers in the cytoplasm and transcriptional activators in the nucleus. STAT proteins act as transcription factors activated by phosphorylation on its tyrosine residues upon stimulation by various cytokines. The phosphorylated STAT molecules then form homo- or heterodimers through SH2-mediated interaction and translocate into the nucleus to activate the transcription of various target genes. STAT5 recognizes the interferon-gamma activated site TTCNNNGAA (GAS sequence) in the promoter region of the beta-casein gene. Except for prolactin-dependent beta-casein production in mammary gland cells, the biological consequences of STAT5a activation in various systems are not clear. Here we showed that STAT5a was phosphorylated 10 min after desferrioxamine (DFO) treatment, and reached a maximum induction at 4 h in mammary epithelial cells (HC11) and transfected COS-7 cells. Under hypoxic conditions (2% O2), a maximal phosphorylation of STAT5a was observed within 6 h. EMSA (electrophoretic mobility shift assay) showed that DFO or hypoxia enhanced the binding activities of STAT5a DNA to beta-casein gene promoter in mammary epithelial cells (HC11) and transfected COS-7 cells. These results showed that DFO or hypoxia induces tyrosine phosphorylation of STAT5a and also increases the binding activity of STAT5a DNA in mammary epithelial cells. Our data suggest that the STAT5 may act as a mediator in hypoxia-mediated gene expression.

Molecular Cloning of Mouse Interleukin-2 Receptor bata-Chain Gene Promoter / 대한면역학회지

No abstract available.