The Effects of Self-Care Intervention Programs for Elderly with Mild Cognitive Impairment.

This study examined the effects of a self-care intervention program on self-efficacy, dementia-preventive behavior, cognitive function, depression, and quality of life in elderly with mild cognitive impairment. The study employed a quasi-experimental study design using a nonequivalent control group pre-post. Data were analyzed using the chi-square test, independent t-test, and repeated-measures ANOVA. The results of the study showed that the program reduced dementia risk and strengthened self-care ability in older adults with MCI.

Anti-photoaging effect of aaptamine in UVB-irradiated human dermal fibroblasts and epidermal keratinocytes.

Chronic exposure to ultraviolet (UV) irradiation causes sunburn, inflammatory responses, skin cancer, and photoaging. Photoaging, in particular, generates reactive oxygen species (ROS) that stimulate mitogen-activated protein kinase (MAPK) signaling and transcription factors. UV irradiation also activates matrix metalloproteinases (MMPs) expression and inactivates collagen synthesis. Aaptamine, a marine alkaloid isolated from the marine sponge, has been reported to have antitumor, antimicrobial, antiviral, and antioxidant activities. However, the photo-protective effects of aaptamine have not been elucidated. In this study, our data demonstrated that aaptamine deactivated UVB-induced MAPK and activator protein-1 signaling by suppressing ROS, resulting in attenuating the expression of MMPs in UVB-irradiated human dermal fibroblasts. Aaptamine also decreased proinflammatory cytokines such as cyclooxygenase-2, tumor necrosis factor-α, interleukin-1ß, and nuclear factor-kappa B subunits in UVB-irradiated human keratinocytes. In conclusion, we suggest that aaptamine represents a novel and effective strategy for treatment and prevention of photoaging.

Panduratin A, an activator of PPAR-α/δ, suppresses the development of oxazolone-induced atopic dermatitis-like symptoms in hairless mice.

AIMS: Panduratin A isolated from Boesenbergia pandurata (Roxb.) has been reported to have antioxidant, anti-inflammatory, and anti-allergic activities. However, the effect of panduratin A on atopic dermatitis (AD) has not been studied. In the present study, we investigated the efficacy of panduratin A, an activator of peroxisome proliferator-activated receptors (PPAR) α/δ, using oxazolone-induced AD-like model in hairless mice. MAIN METHODS: To determine PPARα/δ activation of panduratin A, HaCaT, Hs68, and COS-7 cells were treated with panduratin A, then PPARα/δ and PPAR response element (PPRE) activities were assessed with a reporter gene assay. For the in vivo study, oral administration of panduratin A was performed for 4weeks, with oxazolone treatment every other day. The efficacy of panduratin A on parameters of oxazolone-induced AD was assessed physiologically, morphologically, and immunologically. KEY FINDINGS: Panduratin A increased PPARα/δ and PPRE activation both in vitro and in vivo. Panduratin A attenuated dermatitis-associated barrier damage as demonstrated by transepidermal water loss, erythema, and filaggrin expression. Furthermore, infiltration of inflammatory cells and epidermal thickness in the skin were decreased. Panduratin A decreased serum immunoglobulin (Ig) E and interleukin-4 levels but increased IgG2a and interferon-γ levels. In addition, panduratin A decreased inflammation-associated molecules in the skin. Panduratin A also decreased Th2-associated molecules and increased Th1/regulatory T cell (Treg)-associated molecules in the spleen. SIGNIFICANCE: Panduratin A showed a beneficial effect on AD by modulating Th1/Th2/Treg-associated immune response and is a potential candidate for treating AD.

Fucosterol inhibits matrix metalloproteinase expression and promotes type-1 procollagen production in UVB-induced HaCaT cells.

Ultraviolet (UV) radiation damages human skin and causes skin diseases such as epidermal hyperplasia, sunburn, inflammatory responses and photoaging. Photoaging is associated with upregulated matrix metalloproteinase (MMP) expression and downregulated collagen synthesis. Fucosterol, which is isolated from marine brown algae, has been reported to possess antioxidant and anticancer activities; however, its effects on photoaging are unknown. This study assessed the effects of fucosterol on photoaging and investigated its mechanisms of action in UV-irradiated immortalized human keratinocytes (HaCaT) by enzyme-linked immunosorbent assay, semi-quantitative reverse transcription-polymerase chain reaction, Western blot analysis and 2',7'-dichlorofluorescein diacetate assay. Our results showed that fucosterol attenuated UV-induced MMP and inflammatory cytokine expression by deactivating mitogen-activated protein kinases (MAPKs) induced by reactive oxygen species. Fucosterol also increased type-I procollagen and antioxidant enzyme expression. Taken together, fucosterol regulates the expression of MMPs and type-I procollagen in UV-irradiated HaCaT by modulating MAPK, suggesting it as a potential candidate for prevention and treatment of skin aging.

Effects of macelignan isolated from Myristica fragrans (Nutmeg) on expression of matrix metalloproteinase-1 and type I procollagen in UVB-irradiated human skin fibroblasts.

Exposure to ultraviolet (UV) light causes premature skin aging that is associated with upregulated matrix metalloproteinases (MMPs) and decreased collagen synthesis. Macelignan, a natural lignan compound isolated from Myristica fragrans HOUTT. (nutmeg), has been reported to possess antioxidant and antiinflammatory activities. This study assessed the effects of macelignan on photoaging and investigated its mechanisms of action in UV-irradiated human skin fibroblasts (Hs68) by reverse transcription-polymerase chain reaction, Western blot analysis, 2',7'-dichlorofluorescein diacetate assay, and enzyme-linked immunosorbent assay. Our results show that macelignan attenuated UV-induced MMP-1 expression by suppressing phosphorylation of mitogen-activated protein kinases (MAPKs) induced by reactive oxygen species. Macelignan also increased type I procollagen expression and secretion through transforming growth factor ß (TGF-ß)/Smad signaling. These findings indicate that macelignan regulates the expression of MMP-1 and type I procollagen in UV-irradiated human skin fibroblasts by modulating MAPK and TGF-ß/Smad signaling, suggesting its potential as an efficacious antiphotoaging agent.

Inhibitory effects of panduratin A on allergy-related mediator production in rat basophilic leukemia mast cells.

Immediate-type hypersensitivity is characterized by elevated levels of immunoglobulin E (IgE) and activated mast cell plays a crucial role by releasing granule contents, lipid-derived mediators, cytokines, and chemokines. To evaluate the antiallergic effects of panduratin A isolated from Boesenbergia pandurata Roxb., we determined its effects on calcium (Ca(2+)) influx, degranulation, and inflammatory mediators in calcium ionophore A23187 and phorbol 12-myristate 13-acetate (PMA)-stimulated rat basophilic leukemia (RBL-2H3) cells. Panduratin A (20 µM) inhibited secretion of ß-hexosaminidase (46.69 ± 9.6 %), histamine (34.32 ± 2.1 %), and Ca(2+) influx (43.84 %). Panduratin A reduced the production of prostaglandin E(2) (PGE(2), 47.58 ± 3.4 %), leukotriene B(4) (LTB(4), 98.15 ± 1.6 %), and the mRNA expression of cyclooxygenase-2, 5-lipoxygenase, interleukin (IL)-4, IL-13, and tumor necrosis factor-α. Furthermore, panduarin A attenuated phosphorylation of Akt, the mitogen-activated protein kinases (MAPK) extracellular signal-regulated kinase (ERK), p38, and c-Jun N-terminal kinase (JNK) expression. These results indicate that panduratin A might be useful as an agent against immediate-type hypersensitivity.

Macelignan inhibits histamine release and inflammatory mediator production in activated rat basophilic leukemia mast cells.

Type I allergy is characterized by the release of granule-associated mediators, lipid-derived substances, cytokines, and chemokines by activated mast cells. To evaluate the anti-allergic effects of macelignan isolated from Myristica fragrans Houtt., we determined its ability to inhibit calcium (Ca(2+)) influx, degranulation, and inflammatory mediator production in RBL-2 H3 cells stimulated with A23187 and phorbol 12-myristate 13-acetate. Macelignan inhibited Ca(2+) influx and the secretion of ß-hexosaminidase, histamine, prostaglandin E(2), and leukotriene C(4); decreased mRNA levels of cyclooxygenase-2, 5-lipoxygenase, interleukin-4 (IL-4), IL-13, and tumor necrosis factor-α; and attenuated phosphorylation of Akt and the mitogen-activated protein kinases extracellular signal-regulated kinase, p38, and c-Jun N-terminal kinase. These results indicate the potential of macelignan as a type I allergy treatment.

5,7-Dimethoxyflavone, an activator of PPARα/γ, inhibits UVB-induced MMP expression in human skin fibroblast cells.

Peroxisome proliferator-activated receptors (PPARs), which are members of the nuclear hormone receptor superfamily, are a family of ligand-activated transcription factors that consist of three isotypes (PPAR α, δ and γ). PPAR activity was previously thought to be limited to lipid metabolism and glucose homeostasis; however, intensive studies of PPARα/γ in recent years have revealed their importance in age-related inflammation and photoaging as regulators of cytokines, matrix metalloproteinases (MMPs) and nuclear factor-kappa B (NF-κB). We evaluated the ability of the PPARα/γ activator 5,7-dimethoxyflavone (5,7-DMF) to inhibit ultraviolet B (UVB)-induced MMP expression in Hs68 human skin fibroblasts. Hs68 cells were treated with 5,7-DMF and then exposed to UVB irradiation. MMP expression, production and activity were determined by reverse transcription-polymerase chain reaction, enzyme-linked immunosorbent assay and gelatin zymography. PPARα/γ expression, catalase expression, and mitogen-activated protein kinase (MAPK), activator protein-1 (AP-1) and NF-κB signalling were evaluated by Western blot analysis. PPARα/γ activity was assessed with the GAL4/PPARα/γ transactivation assay. We found that 5,7-DMF strongly decreased MMP expression, production and activity. In addition, 5,7-DMF significantly increased PPARα/γ activation and catalase expression, thereby downregulating UVB-induced reactive oxygen species (ROS) production, ROS-induced MAPK signalling and downstream transcription factors. Finally, 5,7-DMF reduced IκBα phosphorylation, blocked NF-κB p65 nuclear translocation, strongly suppressed proinflammatory cytokines such as interleukin-6 (IL-6) and IL-8. 5,7-DMF prevents UVB-induced MMP expression by suppressing UVB-induced oxidative stress and age-related inflammation via NF-κB and MAPK/AP-1 pathways. Our findings suggest the usefulness of 5,7-DMF for preventing and treating skin photoaging.

Boesenbergia pandurata attenuates diet-induced obesity by activating AMP-activated protein kinase and regulating lipid metabolism.

Obesity, a chronic metabolic disorder, is characterized by enlarged fat mass and dysregulation of lipid metabolism. The medicinal plant, Boesenbergia pandurata (Roxb.) Schltr., has been reported to possess anti-oxidative and anti-inflammatory properties; however, its anti-obesity activity is unexplored. The present study was conducted to determine whether B. pandurata extract (BPE), prepared from its rhizome parts, attenuated high-fat diet (HFD)-induced obesity in C57BL/6J mice. The molecular mechanism was investigated in 3T3-L1 adipocytes and HepG2 human hepatoma cells. BPE treatment decreased triglyceride accumulation in both 3T3-L1 adipocytes and HepG2 hepatocytes by activating AMP-activated protein kinase (AMPK) signaling and regulating the expression of lipid metabolism-related proteins. In the animal model, oral administration of BPE (200 mg/kg/day for 8 weeks) significantly reduced HFD-induced body weight gain without altering the amount of food intake. In addition, elevated serum levels of total cholesterol, low-density lipoprotein cholesterol, and triglycerides were suppressed by BPE administration. Fat pad masses were reduced in BPE-treated mice, as evidenced by reduced adipocyte size. Furthermore, BPE protected against the development of nonalcoholic fatty liver by decreasing hepatic triglyceride accumulation. BPE also activated AMPK signaling and altered the expression of lipid metabolism-related proteins in white adipose tissue and liver. Taken together, these findings indicate that BPE attenuates HFD-induced obesity by activating AMPK and regulating lipid metabolism, suggesting a potent anti-obesity agent.

Age-dependent decline in supragranular long-term synaptic plasticity by increased inhibition during the critical period in the rat primary visual cortex.

Supragranular long-term potentiation (LTP) and depression (LTD) are continuously induced in the pathway from layer 4 during the critical period in the rodent primary visual cortex, which limits the use of supragranular long-term synaptic plasticity as a synaptic model for the mechanism of ocular dominance (OD) plasticity. The results of the present study demonstrate that the pulse duration of extracellular stimulation to evoke a field potential (FP) is critical to induction of LTP and LTD in this pathway. LTP and LTD were induced in the pathway from layer 4 to layer 2/3 in slices from 3-wk-old rats when FPs were evoked by 0.1- and 0.2-ms pulses. LTP and LTD were induced in slices from 5-wk-old rats when evoked by stimulation with a 0.2-ms pulse but not by stimulation with a 0.1-ms pulse. Both the inhibitory component of FP and the inhibitory/excitatory postsynaptic potential amplitude ratio evoked by stimulation with a 0.1-ms pulse were greater than the values elicited by a 0.2-ms pulse. Stimulation with a 0.1-ms pulse at various intensities that showed the similar inhibitory FP component with the 0.2-ms pulse induced both LTD and LTP in 5-wk-old rats. Thus extracellular stimulation with shorter-duration pulses at higher intensity resulted in greater inhibition than that observed with longer-duration pulses at low intensity. This increased inhibition might be involved in the age-dependent decline of synaptic plasticity during the critical period. These results provide an alternative synaptic model for the mechanism of OD plasticity.

A novel mode of action of YC-1 in HIF inhibition: stimulation of FIH-dependent p300 dissociation from HIF-1{alpha}.

Hypoxia-inducible factor (HIF)-1 plays a key role in tumor promotion by inducing approximately 60 genes required for tumor adaptation to hypoxia; thus, it is viewed as a target for cancer therapy. For this reason, YC-1, which down-regulates HIF-1alpha and HIF-2alpha at the post-translational level, is being developed as a novel anticancer drug. We here found that YC-1 acts in a novel manner to inhibit HIF-1. In the Gal4 reporter system, which is not degraded by YC-1, YC-1 was found to significantly inactivate the COOH-terminal transactivation domain (CAD) of HIF-1alpha, whereas it failed to inactivate CAD(N803A) mutant. In coimmunoprecipitation assays, YC-1 stimulated factor inhibiting HIF (FIH) binding to CAD even in hypoxia, whereas it failed to increase the cellular levels of hydroxylated Asn803 of CAD. It was also found that YC-1 prevented p300 recruitment by CAD in mammalian two-hybrid and coimmunoprecipitation assays. The involvement of FIH in YC-1-induced CAD inactivation was confirmed in EPO-enhancer and Gal4 reporter systems using FIH small interfering RNA and dimethyloxalylglycine FIH inhibitor. Indeed, FIH inhibition rescued HIF target gene expressions repressed by YC-1. In cancer cell lines other than Hep3B, YC-1 inhibits HIF-1alpha via the FIH-dependent CAD inactivation as well as via the protein down-regulation. Given these results, we suggest that the functional inactivation of HIF-alpha contributes to the YC-1-induced deregulation of hypoxia-induced genes.

Racial and ethnic comparisons of nursing home residents at admission.

OBJECTIVE: To present racial/ethnic comparisons of comprehensive profiles of nursing home residents at admission, including whites, African Americans, Hispanics, Asians/Pacific Islanders, and American Indians/Alaska Natives. METHODS: More than 885,000 admission assessments recorded in the national Minimum Data Set (MDS) were analyzed. Racial and ethnic analyses of the MDS admission assessments were conducted using the software package SAS. RESULTS: There were significant racial/ethnic differences in gender and age, with minority residents more likely to be male and younger. African American, Hispanic, and Asian/Pacific Islanders were significantly more likely than white residents to exhibit total dependence in the self-performance of the ADLs and to have greater cognitive impairments, with Asian/Pacific Islanders the most physically dependent and cognitively impaired. DISCUSSION: The results illustrate significant and substantive differences among the racial/ethnic groups for many demographic characteristics, as well as health-related indicators and conditions. This analysis suggests that the general perspective that economically disadvantaged minorities enter nursing homes in worse condition than whites is too simplistic. More research, particularly qualitative studies of specific minority groups, will advance our understanding of why members of some racial/ethnic groups require nursing home placement sooner than other groups.

Curcumin attenuates cytochrome P450 induction in response to 2,3,7,8-tetrachlorodibenzo-p-dioxin by ROS-dependently degrading AhR and ARNT.

TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) is a highly toxic environmental contaminant. When exposed to TCDD, mammalian cells undergo malignant transformation via abnormal intracellular signaling cascades, and the robust inductions of cytochrome P450 (CYP) enzymes are considered to mediate carcinogenesis by producing genotoxic metabolites. We here examined whether curcumin has preventive activity against TCDD-induced CYP production and cell transformation. Initially, the cellular levels of cytochrome P450 (CYP) 1A1 and 1B1 were examined, because these are known to generate estrogen metabolites that mediate genotoxic stress. Curcumin inhibited CYP1A1 and 1B1 induction by TCDD at the mRNA and protein levels. Notably, the nuclear levels of arylhydrocarbon receptor (AhR) and AhR nuclear translocator (ARNT) were decreased by curcumin, but those in the cytoplasm were not. It was also found that oxidative stress mediated the curcumin-induced degradations of AhR and ARNT. Furthermore, in vitro transformation assays showed that in normal human embryonic kidney cells and normal prostate cells curcumin prevents the anchorage-independent growth induced by TCDD. In conclusion, curcumin attenuates AhR/ARNT-mediated CYP induction by dioxin and presumably this mode-of-action may be responsible for the curcumin prevention of malignant transformation. The findings of this study should be found helpful in the design stage of pharmacodynamic studies for developing curcumin as a chemopreventive or anticancer agent.

Exendin-4 induction of Egr-1 expression in INS-1 beta-cells: interaction of SRF, not YY1, with SRE site of rat Egr-1 promoter.

Glucagon-like peptide-1 (GLP-1) induces several immediate early response genes such as c-fos, c-jun, and early growth response-1 (Egr-1), which are involved in cell proliferation and differentiation. We recently reported that exendin-4 (EX-4), a potent GLP-1 agonist, upregulated Egr-1 expression via phosphorylation of CREB, a transcription factor in INS-1 beta-cells. This study was designed to investigate the role of another transcription factors, serum response factor (SRF) and Yin Yang-1 (YY1), in EX-4-induced Egr-1 expression. EX-4 significantly increased Egr-1 mRNA and subsequently its protein level. EX-4-induced Egr-1 expression was inhibited by pretreatment with a PKA inhibitor, H-89, and an MEK inhibitor, PD 98059. The siRNA-mediated inhibition of PKA and ERK1 resulted in significant reduction of EX-4-induced Egr-1 expression. Promoter analyses showed that SRE clusters were essential for Egr-1 transcription, and YY1 overexpression did not affect Egr-1 promoter activity. EMSA results demonstrated that EX-4-induced transient increase in DNA-protein complex on SRE site, and that both SRF and phospho-SRF were bound to this site. Treatment of either YY1 consensus oligonucleotide or YY1 antibody did not effect the change of density or migration of the DNA-protein complex. Collectively, EX-4-induced Egr-1 expression is largely dependent on cAMP-mediated extracellular signal-regulated kinase activation, and EX-4 induces Egr-1 transcription via the interaction of SRF and phospho-SRF to SRE sites.

Differential cholinergic modulation of Ca2+ transients evoked by backpropagating action potentials in apical and basal dendrites of cortical pyramidal neurons.

The effect of the cholinergic agonist carbachol (CCh) on backpropagating action potential (bAP)-evoked Ca2+ transients in distal apical and basal dendrites of layer 2/3 pyramidal neurons in the primary visual cortex of rats was studied using whole cell recordings and confocal Ca2+ imaging. In the presence of CCh (20 microM), initial bAP-evoked Ca2+ transients were followed by large propagating secondary Ca2+ transients that were restricted to proximal apical dendrites < or =40 microm from the soma. In middle apical dendrites (41-100 microm from the soma), Ca2+ transients evoked by AP bursts at 20 Hz, but not by single APs, were increased by CCh without secondary transients. CCh failed to increase the bAP-evoked Ca2+ transients in distal apical dendrites (101-270 microm from the soma). In contrast, in basal dendrites, CCh increased Ca2+ transients evoked by AP bursts, but not by single APs, and these transients were relatively constant over the entire length of the dendrites. CCh further increased the enhanced bAP-evoked Ca2+ transients in the presence of 4-aminopyridine (200 microM), an A-type K+ channel blocker, in basal and apical dendrites, except in distal apical dendrites. CCh increased large Ca2+ transients evoked by high-frequency AP bursts in basal dendrites, but not in distal apical dendrites. CCh-induced increase in Ca2+ transients was mediated by InsP3-dependent Ca2+-induced Ca2+-release. These results suggest that cholinergic stimulation differentially increases the bAP-evoked increase in [Ca2+]i in apical and basal dendrites, which may modulate synaptic activities in a location-dependent manner.

CCAAT box is required for the induction of human thrombospondin-1 gene by trichostatin A.

Histone deacetylase (HDAC) inhibitors have been reported to inhibit angiogenesis as well as tumor growth. Thrombospondin-1 (TSP1) has been recognized as a potent inhibitor of angiogenesis. Such an action of TSP1 may account for the effect of HDAC inhibitors. In the present study, we investigated the molecular mechanism by which trichostatin A, a HDAC inhibitor, induces the expression of TSP1 gene. Trichostatin A increased both mRNA and protein levels of TSP1 in HeLa cells. Promoter and actinomycin D chase assays showed that trichostatin A-induced TSP1 expression was regulated at the transcriptional level without changing mRNA stability. CCAAT box on the TSP1 promoter was found to primarily mediate the trichostatin A response by deletion and mutation analyses of the TSP1 promoter. Electrophoretic mobility shift assay indicated that CCAAT-binding factor (CBF) was specifically bound to the CCAAT box of TSP1 promoter. Moreover, chromatin immunoprecipitation assay showed that trichostatin A increased the binding of acetylated form of histone H3 to the CCAAT box region of TSP1 promoter. Taken together, these results strongly suggest that trichostatin A activates the transcription of TSP1 gene through the binding of transcription factor CBF to CCAAT box and the enhanced histone acetylation. Thus, the present study provides the clue that the inhibition of angiogenesis by trichostatin A is accomplished through the upregulation of TSP1, the anti-angiogenic factor.

HIF-1alpha controls keratinocyte proliferation by up-regulating p21(WAF1/Cip1).

The cyclin-dependent kinase inhibitor p21(WAF1/Cip1) plays a central role in a spatial and temporal balance of epidermal keratinocyte proliferation and growth arrest. However, what controls p21 expression in keratinocytes remains uncertain. Hypoxia-inducible factor 1alpha (HIF-1alpha) does not only express a variety of genes essential for hypoxic adaptation, but also up-regulates p21 so as to slow down cell cycle under hypoxic conditions. In the present study, we examined the role of HIF-1alpha in p21-mediated growth arrest of keratinocyte. Keratinocyte proliferation was arrested in the G1 phase at a high cell density. p21 was also up-regulated in a cell density-dependent manner and was found to be highly expressed in epidermal keratinocytes of normal human skins. In addition, in the same specimens and cells, we noted robust HIF-1alpha expression. HIF-1alpha siRNAs inhibited p21 expression and released the G1 arrest. In vivo, moreover, the intradermal injection of HIF-1alpha siRNA attenuated p21 expression in rat epidermis and induced skin hyperplasia. Mechanistically, we propose that the production of mitochondrial reactive oxygen species and the activation of the MEK/ERK pathway are involved in the HIF-1alpha stabilization in keratinocytes. These results imply that HIF-1alpha functions as an up-stream player in the p21-mediated growth arrest of keratinocytes.

Contribution of HIF-1alpha or HIF-2alpha to erythropoietin expression: in vivo evidence based on chromatin immunoprecipitation.

Circulating erythropoietin (EPO) is mainly produced by the kidneys and mediates erythrogenesis in bone marrow and nonhematopoietic cell survival. EPO is also produced in other tissues where it functions as a paracrine. Moreover, the hypoxic induction of EPO is known to be mediated by HIF-1alpha and HIF-2alpha, but it remains obscure as to which of these two mediators mainly contributes to EPO expression. Thus, we designed in vivo experiments to evaluate the contributions made by HIF-1alpha and HIF-2alpha to EPO expression. In mice exposed to mild whole body hypoxia, HIF-1alpha and HIF-2alpha were both induced in all tissues examined. However, EPO mRNA was expressed in kidney and brain, but not in liver and lung. Likewise, chromatin immunoprecipitation (CHIP) analyses demonstrated that HIF-1alpha or HIF-2alpha binding to the EPO gene increased under hypoxic conditions only in kidney and brain. A comparison of CHIP data and EPO mRNA levels suggested that, during mild hypoxia, renal EPO transcription is induced equally by HIF-1alpha and HIF-2alpha, but that brain EPO is mainly induced during hypoxia by HIF-2alpha. Thus, HIF-1alpha and HIF-2alpha appear to contribute to EPO expression tissue specifically.

Caffeic acid and its synthetic derivative CADPE suppress tumor angiogenesis by blocking STAT3-mediated VEGF expression in human renal carcinoma cells.

Tumor angiogenesis is required for tumor development and is stimulated by angiogenic inducers like VEGF (vascular endothelial growth factor). Our previous study demonstrated that STAT3 (signal transducer and activator of transcription 3) up-regulates HIF-1alpha (hypoxia inducible factor-1alpha) protein stability and enhances HIF-1-mediated VEGF expression in hypoxic solid tumor cells, thus suggesting that the inhibition of STAT3 signaling may have clinical applications. In this study, we examined in vitro and in vivo, whether caffeic acid (CA) or its derivative CADPE [3-(3,4-dihydroxy-phenyl)-acrylic acid 2-(3,4-dihydroxy-phenyl)-ethyl ester] exert anticancer activity by targeting STAT3. It was found that CA or CADPE significantly inhibit STAT3 activity, and that this in turn down-regulates HIF-1alpha activity. Consequently, sequential blockade of STAT3 and HIF-1alpha resulted in the down-regulation of VEGF by inhibiting their recruitment to the VEGF promoter. In mice bearing a Caki-I carcinoma, both CA and CADPE retarded tumor growth and suppressed STAT3 phosphorylation, HIF-1alpha expression, vascularization and STAT3-inducible VEGF gene expression in tumors. Taken together, our results demonstrate that CA and CADPE are potential inhibitors of STAT3 and that they suppress tumor angiogenesis by inhibiting the activity of STAT3, the expression of HIF-1alpha and VEGF.

Open channel block of A-type, kv4.3, and delayed rectifier K+ channels, Kv1.3 and Kv3.1, by sibutramine.

The effects of sibutramine on voltage-gated K+ channel (Kv)4.3, Kv1.3, and Kv3.1, stably expressed in Chinese hamster ovary cells, were investigated using the whole-cell patch-clamp technique. Sibutramine did not significantly decrease the peak Kv4.3 currents, but it accelerated the rate of decay of current inactivation in a concentration-dependent manner. This phenomenon was effectively characterized by integrating the total current over the duration of a depolarizing pulse to +40 mV. The IC50 value for the sibutramine block of Kv4.3 was 17.3 microM. Under control conditions, the inactivation of Kv4.3 currents could be fit to a biexponential function, and the time constants for the fast and slow components were significantly decreased after the application of sibutramine. The association (k+1) and dissociation (k-1) rate constants for the sibutramine block of Kv 4.3 were 1.51 microM-1s-1 and 27.35 s-1, respectively. The theoretical KD value, derived from k-1/k+1, yielded a value of 18.11 microM. The block of Kv4.3 by sibutramine displayed a weak voltage dependence, increasing at more positive potentials, and it was use-dependent at 2 Hz. Sibutramine did not affect the time course for the deactivating tail currents. Neither steady-state activation and inactivation nor the recovery from inactivation was affected by sibutramine. Sibutramine caused the concentration-dependent block of the Kv1.3 and Kv3.1 currents with an IC50 value of 3.7 and 32.7 microM, respectively. In addition, sibutramine reduced the tail current amplitude and slowed the deactivation of the tail currents of Kv1.3 and Kv3.1, resulting in a crossover phenomenon. These results indicate that sibutramine acts on Kv4.3, Kv1.3, and Kv3.1 as an open channel blocker.