-
[show abstract]
[hide abstract]
ABSTRACT: A new strategy for fast fluorescent detection of cysteine (Cys), based on a response-assisted electrostatic attraction, is demonstrated. By utilizing this strategy, we designed and synthesized three fluorescent probes for the specific detection of Cys under actual physiological conditions. The probe m-CP, a coumarin fluorophore conjugated with a substituted methyl pyridinium group through an unsaturated ketone unit, showed highly selective and sensitive detection for cysteine (Cys) over homocysteine (Hcy) and glutathione (GSH). The kinetic analysis indicated that the sensing process was highly accelerated (a response time less than 1 min) by the response-assisted electrostatic attraction. More importantly, control experiments with isomeric probes first demonstrated that the spatial charge configuration of the probe played an important role in Cys-preferred selectivity and kinetic rate acceleration. Furthermore, the practical utility of the probe m-CP in the fluorescent labeling of Cys residues within proteins was demonstrated. Finally, these probes were employed in living cell imaging with HeLa cells, in which it displayed satisfactory cell permeability and enabled us to distinguish active thiols in the cytoplasm, nucleus, and mitochondria.
Chemistry 04/2013; · 5.93 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A new turn-on fluorescent probe for fast detection of cysteine in physiological conditions, based on a new response-assisted electrostatic attraction strategy, is reported. The practical utility of the probe in fluorescent protein labeling and subcellular imaging is also demonstrated.
Chemical Communications 07/2012; 48(70):8793-5. · 6.17 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: BACKGROUND: Cryptopleurine, a phenanthroquinolizidine alkaloid, was known to exhibit anticancer activity; however, the underlying mechanism is poorly understood. Because the nuclear factor-κB (NF-κB) transcription factors control many physiological processes including inflammation, immunity, and development and progression of cancer, we investigated the effects of cryptopleurine on tumor necrosis factor alpha (TNF-α)-induced NF-κB activation pathway and on the expression of NF-κB-regulated gene products associated with many pathophysiological processes. METHODOLOGY AND PRINCIPAL FINDING: MDA-MB231, MDA-MB435, MCF-7, HEK293, RAW264.7 and Hep3B cells were used to examine cryptopleurine's effect on the NF-κB activation pathway. Major assays were promoter-reporter gene assay, electrophoretic mobility shift assay (EMSA), in vitro immune complex kinase assay, real-time PCR, Western blot analysis, and Matrigel invasion assay. Experiments documenting cell proliferation and apoptosis were analyzed by MTT method and flow cytometry, respectively. The results indicated that cryptopleurine suppressed the NF-κB activation through the inhibition of IκB kinase (IKK) activation, thereby blocking the phosphorylation and degradation of the inhibitor of NF-κB alpha (IκBα) and the nuclear translocation and DNA-binding activity of p65. The suppression of NF-κB by cryptopleurine led to the down-regulation of gene products involved in inflammation, cell survival, proliferation, invasion, and angiogenesis. CONCLUSIONS AND SIGNIFICANCE: Our results show that cryptopleurine inhibited NF-κB activation pathway, which leads to inhibition of inflammation, proliferation, and invasion, as well as potentiation of apoptosis. Our findings provide a new insight into the molecular mechanisms and a potential application of cryptopleurine for inflammatory diseases as well as certain cancers associated with abnormal NF-κB activation.
PLoS ONE 01/2012; 7(6):e40355. · 4.09 Impact Factor
-
Juan Ma,
He Liang,
Hong Ri Jin,
Nguyen Tien Dat,
Shan Yu Zhang,
Ying Zi Jiang,
Ji Xing Nan,
Donghao Li,
Xue Wu,
Jung Joon Lee, Xuejun Jin
[show abstract]
[hide abstract]
ABSTRACT: The nuclear factor-κB (NF-κB) transcription factors control many physiological processes including inflammation, immunity, and apoptosis. In our search for NF-κB inhibitors from natural resources, we identified yangonin from Piper methysticum as an inhibitor of NF-κB activation. In the present study, we demonstrate that yangonin potently inhibits NF-κB activation through suppression of the transcriptional activity of the RelA/p65 subunit of NF-κB. This compound significantly inhibited the induced expression of the NF-κB-reporter gene. However, this compound did not interfere with tumor necrosis factor-α (TNF-α)-induced inhibitor of κBα (IκBα) degradation, p65 nuclear translocation, and DNA-binding activity of NF-κB. Further analysis revealed that yangonin inhibited not only the induced NF-κB activation by overexpression of RelA/p65, but also transactivation activity of RelA/p65. Moreover, yangonin did not inhibit TNF-α-induced activation of p38, but it significantly impaired activation of extracellular signal-regulated kinase 1/2 and stress-activated protein kinase/c-Jun NH(2)-terminal kinase. We also demonstrated that pretreatment of cells with this compound prevented TNF-α-induced expression of NF-κB target genes, such as interleukin 6, interleukin 8, monocyte chemotactic protein 1, cyclooxygenase-2 and inducible nitric oxide. Taken together, yangonin could be a valuable candidate for the intervention of NF-κB-dependent pathological conditions such as inflammation.
Journal of Pharmacological Sciences 01/2012; 118(4):447-54. · 2.08 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Cryptotanshinone (CTN), one of the major constituents of tanshinones, was investigated for anti-inflammatory activity in the murine macrophage cell line RAW 264.7. CTN inhibited the production of nitric oxide (NO) production, as well as expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) in lipopolysaccharide (LPS)-stimulated macrophages. Since CTN was considered as inhibiting LPS-triggered phosphorylation of mitogen-activated protein kinase (MAPK) and nuclear factor (NF)-κB activation, we consequently evaluated the expression of toll-like receptor 4 (TLR4) and CD14, as well as phosphorylation of TGF-β-activated kinase 1 (TAK1). CTN reduced the expression of CD14 and TLR4, and suppressed LPS-induced phosphorylation of TAK1. Furthermore, CTN significantly increased the survival rate against LPS challenge in D-galactosamine-sensitized mice, which was in line with in vitro results. These results suggested that CD14/TLR4 and TAK1 might be the potential molecular targets for addressing the protective effects of CTN on LPS-induced inflammatory effects in macrophages.
International immunopharmacology 08/2011; 11(11):1871-6. · 2.21 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A new water-soluble receptor 1 has been synthesized and it showed selective recognition of zwitterionic arginine in aqueous media. Moreover, the receptor 1 could be regard as a facile tool for protein labeling and quantitative determination (LOD = 15 nM).
Chemical Communications 02/2011; 47(13):3921-3. · 6.17 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Cucurbitacin B, a natural triterpenoid is well-known for its strong anticancer activity, and recent studies showed that the compound inhibits JAK/STAT3 pathway. In this study, we demonstrate for the first time that cucurbitacin B is also a potent inhibitor of NF-κB activation. Our results showed that cucurbitacin B inhibited TNF-α-induced expression of NF-κB reporter gene and NF-κB target genes in a dose-dependent manner, however, it did not prevent either stimuli-induced degradation of IκBα or nuclear translocation and DNA-binding activity of NF-κB. On the other hand, cucurbitacin B dose-dependently suppressed not only NF-κB activation induced by overexpression of RelA/p65 but also transactivation activity of RelA/p65 subunit of NF-κB. Consistently, treatment of HeLa cells with the compound significantly suppressed TNF-α-induced activation of Akt and phosphorylation of Ser536 in RelA/p65, which is required for transactivation activity. Consequently, cucurbitacin B inhibited TNF-α-induced expression of NF-κB-dependent anti-apoptotic proteins such as c-IAP1, c-IAP2, XIAP, TRAF1, and TRAF2 and sensitized TNF-α-induced cell death. Taken together, our results demonstrated that cucurbitacin B could be served as a valuable candidate for the intervention of NF-κB-dependent pathological condition such as cancer.
Journal of Cellular Biochemistry 02/2011; 112(6):1643-50. · 2.87 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: LIGHT is a member of tumor necrosis factor (TNF) superfamily, and its function is mediated through lymphotoxin-β receptor (LTβR), which is known to play important roles in inflammatory and immune responses through activation of NF-κB signaling pathways. However, molecular mechanism of LTβR ligation-induced NF-κB signaling remains incompletely understood. In this report we demonstrate that a novel zinc-finger protein 91 (ZFP91) is a critical regulator in LIGHT-induced activation of non-canonical NF-κB pathway. ZFP91 appears to be required for NF-κB2 (p100) processing to p52, nuclear translocation of p52 and RelB, and DNA-binding activity of NF-κB in LIGHT-induced activation of non-canonical NF-κB pathway. Furthermore, ZFP91 knock-down by RNA interference blocks the LIGHT-induced accumulation of NIK and p100 processing, as well as the expression of non-canonical NF-κB target genes. These data clearly indicate that ZFP91 is a key regulator in LIGHT-induced activation of non-canonical NF-κB pathway in LTβR signaling.
Biochemical and Biophysical Research Communications 10/2010; 400(4):581-6. · 2.48 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The NF-κB transcription factors control many physiological processes, including inflammation, immunity, and apoptosis. Its activity contributes to the development of various cell malignancies. NF-κB-inducing kinase (NIK) plays a pivotal role in NF-κB activation. However, the molecular mechanism to stabilize and activate NIK remains elusive, although it is known that cIAP1/2 (cellular inhibitor of apoptosis 1 and 2) ubiquitinate NIK for degradation. Here, we report a novel NF-κB-related zinc finger protein 91 (ZFP91) that stabilizes and activates NIK in a ubiquitination-dependent manner. We show that ZFP91 interacts with and promotes the Lys(63)-linked ubiquitination of NIK and subsequent processing of p100 to p52. The results of in vitro biochemical assays indicate that ZFP91 functions as an E3 ligase directly to NIK. Remarkably, the ubiquitination of NIK coincides with its Thr(559) phosphorylation. Furthermore, knockdown of ZFP91 expression by RNA interference inhibits the CD40 ligation-induced activation of NIK and p100 processing as well as the expression of noncanonical NF-κB target genes. These data clearly indicate that ZFP91 is an important regulator of the noncanonical NF-κB pathway.
Journal of Biological Chemistry 10/2010; 285(40):30539-47. · 4.77 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Hypoxia-inducible factor-1 and nuclear factor-kappaB have become important targets in cancer treatment due to their critical role in the regulation of genes involved in tumorigenesis. Bioassay-guided fractionation of the methanol extract of Trichosanthes kirilowii seeds led to the isolation of a naturally rare isoaurone, 4',6-dihydroxy-4-methoxyisoaurone (1), together with three known compounds, cucurbitacin B (2), 6-(3-hydroxy-4-methoxystyryl)-4-methoxy-2H-pyran-2-one (3), and blumenol A (4). All compounds inhibited HIF-1 and NF-kappaB activities in reporter assays. Compounds 1-3 potently inhibited HIF-1alpha accumulation and VEGF secretion under hypoxic condition. These results suggest that the tumor cell growth inhibitory activity of T. kirilowii is likely associated with the inhibition of HIF-1 and NF-kappaB activities.
Journal of Natural Products 05/2010; 73(6):1167-9. · 3.13 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The hepatoprotective effects of sarmentosin-containing extracts of Sedum sarmentosum (SS) in D-galactosamine (D-GalN) / lipopolysaccharide (LPS)-induced fulminant hepatic failure mouse model. Pretreatment with SS markedly protected mice from lethal liver injury, which has known to be associated with an abrupt elevation of serum tumor necrosis factor (TNF)-α level. Indeed, SS significantly blocked the elevation of TNF-α and alanine aminotransferase and aspartate aminotransferase as well. SS also remarkably reduced number of apoptotic hepatocytes and DNA fragmentation in the liver, which correlated with blockade of caspase-3 activation. In addition, SS suppressed the increased expression of toll-like receptor 4 (TLR4). The activation of c-Jun NH(2)-terminal kinase, extracellular signal-regulated kinase, and p38 induced by D-GalN/LPS was also significantly suppressed by SS treatment. Furthermore, SS significantly inhibited the activation of nuclear factor-κB. In RAW 264.7 cells stimulated with LPS, TNF-α release and TLR4 expression was suppressed by SS pretreatment, which was in line with in vivo results. These findings suggested that SS prevents D-GalN/LPS-induced fulminant hepatic failure, and this protection is likely associated with its anti-apoptotic activity and the down-regulation of mitogen activated protein kinase activity associated at least in part with suppressing the transcription of LPS receptors.
Journal of Pharmacological Sciences 01/2010; 114(2):147-57. · 2.08 Impact Factor
-
Mi-Sun Won,
Namhui Im,
Soohyun Park,
Shanthaveerappa K Boovanahalli,
Yinglan Jin, Xuejun Jin,
Kyung-Sook Chung,
Moorim Kang,
Kiho Lee,
Song-Kyu Park,
Hwan Mook Kim,
Byoung Mog Kwon,
Jung Joon Lee,
Kyeong Lee
[show abstract]
[hide abstract]
ABSTRACT: Hypoxia-inducible factor (HIF)-1 is a therapeutic target in solid tumors. We report the novel benzimidazole analogue AC1-004, obtained from a chemical library using an HRE-dependent cell-based assay in colorectal carcinoma HCT-116 cells. The accumulation of hypoxia-induced HIF-1alpha was inhibited by compound AC1-004 in various cancer cells, including HCT-116, MDA-MB435, SK-HEP1, and Caki-1. Further, AC1-004 down-regulated VEGF and EPO, target genes of HIF-1, and inhibited in vitro tube formation of HUVEC, suggesting its potential inhibitory activity on angiogenesis. Importantly, AC1-004 was found to regulate the stability of HIF-1alpha through the Hsp90-Akt pathway, leading to the degradation of HIF-1alpha. An in vivo antitumor study demonstrated that AC1-004 reduced tumor size significantly (i.e., by 58.6%), without severe side effects. These results suggest the benzimidazole analogue AC1-004 is a novel HIF inhibitor that targets HIF-1alpha via the Hsp90-Akt pathway, and that it can be used as a new lead in developing anticancer drugs.
Biochemical and Biophysical Research Communications 06/2009; 385(1):16-21. · 2.48 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Hypoxia-inducible factor-1 (HIF-1) is the central mediator of cellular responses to low oxygen concentrations and vital to many aspects of cancer biology. Bioassay-guided fractionation of the chloroform-soluble extracts of Morus species using a hypoxia response element (HRE)-dependent reporter assay led to identification of six benzofurans (1-6) and two chalcone-derived Diels-Alder adducts (7, 8) from Mori Cortex Radicis and three prenylated benzofurans (9-11) and four chalcone-derived Diels-Alder adducts (12-15) from Morus bombycis. The structure of the new 2-arylbenzofuran-type compound, moracin Q (3), was elucidated by spectroscopic methods, and the absolute configuration of 2 was determined for the first time. The selected compounds (1-3, 5, 7, 9, 10, and 12) from the cell-based reporter assay were found to inhibit hypoxia-induced HIF-1alpha accumulation in a dose-dependent manner in human hepatocelluar carcinoma cell-line Hep3B cells. Furthermore, these compounds were also active against hypoxia-induced vascular endothelial growth factor (VEGF) secretion in Hep3B cells.
Journal of Natural Products 01/2009; 72(1):39-43. · 3.13 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Hypoxia-inducible factor-1 (HIF-1) is the central mediator of cellular responses to low oxygen and vital to many aspects of cancer biology. In a search for HIF-1 inhibitors, we identified a quassinoid 6alpha-tigloyloxychaparrinone (TCN) as an inhibitor of HIF-1 activation from Ailantus altissima. We here demonstrated the effect of TCN on HIF-1 activation induced by hypoxia or CoCl2. TCN showed the potent inhibitory activity against HIF-1 activation induced by hypoxia in various human cancer cell lines. This compound markedly decreased the hypoxia-induced accumulation of HIF-1alpha protein dose-dependently, whereas it did not affect the expressions of HIF-1beta and topoisomerase-I. Furthermore, TCN prevented hypoxia-induced expression of HIF-1 target genes for vascular endothelial growth factor (VEGF) and erythropoietin. Further analysis revealed that TCN strongly inhibited HIF-1alpha protein synthesis, without affecting the expression level of HIF-1alpha mRNA or degradation of HIF-1alpha protein. Moreover, the levels of phosphorylation of extracellular signal-regulated kinase-1/2 (ERK1/2), mitogen-activated protein (MAP) kinase-interacting protein kinase-1 (MNK1) and eukaryotic initiation factor 4E (eIF4E) were significantly suppressed by the treatment of TCN, without changing the total levels of these proteins. Our data suggested that TCN may exhibit anticancer activity by inhibiting HIF-1alpha translation through the inhibition of eIF4E phosphorylation pathway and thus provide a novel mechanism for the anticancer activity of quassinoids. TCN could be a new HIF-1-targeted anticancer agent and be effective on mammalian target of rapamycin (mTOR)-targeted cancer therapy, in which mTOR inhibition increases eIF4E phosphorylation.
European Journal of Pharmacology 09/2008; 592(1-3):41-7. · 2.52 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: We report a new series of HIF-1alpha inhibitors which were obtained through structural modifications of previously reported lead 1. The in vitro inhibitory potencies of newly synthesized compounds were evaluated against hypoxia-induced HIF-1 activation using cell-based reporter assay in three human cancer cell lines including SK-Hep-1, Hep3B, and AGS cells. Several compounds displayed significant inhibitory activity in all the three tested cell lines. In particular, analogue 17 displayed potent inhibition of hypoxia-induced accumulation of HIF-1alpha protein in Hep3B cell line, in addition to the dose-dependent inhibition of HIF-1 target genes VEGF and EPO.
Bioorganic & Medicinal Chemistry Letters 12/2007; 17(22):6305-10. · 2.55 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The hypoxia-inducible factor-1 (HIF-1) has been known to be correlated to the adaptation and proliferation of tumor cells; therefore HIF-1 has become an important target in the development of anticancer drugs. A phytochemical study of the CHCl3-soluble fraction of Salvia miltiorrhiza, which strongly inhibited hypoxia-induced reporter gene expression, led to the isolation of 12 abietane-type diterpenes. Of these compounds, sibiriquinone A (1), sibiriquinone B (2), cryptotanshinone (3), and dihydrotanshinone I (4) potently inhibited hypoxia-induced luciferase expression with IC50 values of 0.34, 3.36, 1.58, and 2.05 microM on AGS cells, a human gastric cancer cell line, and 0.28, 3.18, 1.36, and 2.29 microM on Hep3B cells, a human hepatocarcinoma cell line, respectively. Consistently, 1 and 4 dose-dependently suppressed the HIF-1alpha accumulation and 1 inhibited mRNA expression of vascular endothelial growth factor (VEGF) under hypoxia. These results suggest that the anticancer activity of tanshinones is likely at least in part associated with their inhibition of HIF-1 accumulation.
Journal of Natural Products 08/2007; 70(7):1093-7. · 3.13 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Structural modification of a compound discovered during screening using an HRE-dependent reporter assay has revealed a novel class of HIF-1 inhibitors, which potently inhibit the HIF-1alpha protein accumulation and its target gene expression under hypoxic conditions in human hepatocellular carcinoma Hep3B cells.
Journal of Medicinal Chemistry 05/2007; 50(7):1675-84. · 5.25 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A bioassay-guided phytochemical investigation on the methanol extract of Boehmeria pannosa, using a HIF-1-mediated reporter gene assay, led to the isolation of two phenanthroquinolizidine alkaloids, (-)-cryptopleurine (1) and (-)-(15R)-hydroxycryptopleurine (2). The structure of the new compound 2 was determined by spectroscopic methods. Compounds 1 and 2 potently inhibited the hypoxia-induced expression of a reporter gene under the control of a hypoxia response element (HRE) with IC(50) values of 8.7 and 48.1 nM, respectively. Furthermore, 1 and 2 suppressed the accumulation of HIF-1alpha protein in a dose-dependent manner, but not the HIF-1beta protein and inhibited expression of vascular endothelial growth factor (VEGF) by hypoxia.
Journal of Natural Products 08/2006; 69(7):1095-7. · 3.13 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Nuclear factor-kappaB (NF-kappaB) and the signaling pathways that regulate its activity have become a focal point for intense drug discovery and development efforts. NF-kappaB regulates the transcription of a large number of genes, particularly those involved in immune, inflammatory, and antiapoptotic responses. In our search for NF-kappaB inhibitors from natural resources, we identified cardamomin, 2',4'-dihydroxy-6'-methoxychalcone, as an inhibitor of NF-kappaB activation from Alpinia conchigera Griff (Zingiberaceae). In present study, we demonstrated the effect of cardamomin on NF-kappaB activation in lipopolysaccharide (LPS)-stimulated RAW264.7 cells and LPS-induced mortality. This compound significantly inhibited the induced expression of NF-kappaB reporter gene by LPS or tumor necrosis factor (TNF)-alpha in a dose-dependent manner. LPS-induced production of TNF-alpha and NO as well as expression of inducible nitric-oxide synthase and cyclooxygenase-2 was significantly suppressed by the treatment of cardamomin in RAW264.7 cells. Also, cardamomin inhibited not only LPS-induced degradation and phosphorylation of inhibitor kappaBalpha (IkappaBalpha) but also activation of inhibitor kappaB (IkappaB) kinases and nuclear translocation of NF-kappaB. Further analyses revealed that cardamomin did not directly inhibit IkappaB kinases, but it significantly suppressed LPS-induced activation of Akt. Moreover, cardamomin suppressed transcriptional activity and phosphorylation of Ser536 of RelA/p65 subunit of NF-kappaB. However, this compound did not inhibit LPS-induced activation of extracellular signal-regulated kinase and stress-activated protein kinase/c-Jun NH(2)-terminal kinase, but significantly impaired activation of p38 mitogen-activated protein kinase. We also demonstrated that pretreatment of cardamomin rescued C57BL/6 mice from LPS-induced mortality in conjunction with decreased serum level of TNF-alpha. Together, cardamomin could be valuable candidate for the intervention of NF-kappaB-dependent pathological condition such as inflammation.
Journal of Pharmacology and Experimental Therapeutics 02/2006; 316(1):271-8. · 3.83 Impact Factor
