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  • The inhibitors of apoptosis (IAPs) and their emerging role in cancer. 9916987

    The inhibitor of apoptosis protein family has been characterized over the past 5 years, initially in baculovirus and more recently in metazoans. The IAPs are a widely expressed gene family of apoptotic inhibitors from both phylogenic and physiologic points of view. The diversity of triggers against which the IAPs suppress apoptosis is greater than that observed for any other family of apoptotic inhibitors including the bcl-2 family. The central mechanisms of IAP apoptotic suppression appear to be through direct caspase and pro-caspase inhibition (primarily caspase 3 and 7) and modulation of and by the transcription factor NF-kappaB. Although evidence for a direct oncogenic role for the IAPs has yet to be delineated, a number of lines of evidence point towards this class of protein playing a role in oncogenesis. The strongest evidence for IAP involvement in cancer is seen in the IAP called survivin. Although not observed in adult differentiated tissue, survivin is present in most transformed cell lines and cancers tested to date. Survivin has been shown to inhibit caspase directly and apoptosis in general, moreover survivin protein levels correlate inversely with 5 year survival rates in colorectal cancer. Recent data has also implicated survivin in cell cycle control. The second line of evidence for IAP involvement in cancer comes from their emerging role as mediators and regulators of the anti-apoptotic activity of v-Rel and NF-kappaB transcription factor families. The IAPs have been shown to be induced by NF-kappaB or v-Rel in multiple cell lines and conversely, HIAP1 and HIAP2 have been shown to activate NF-kappaB possibly forming a positive feed-back loop. Overall a picture consistent with an IAP role in tumour progression rather than tumour initiation is emerging making the IAPs an attractive therapeutic target.
    Dokumententyp:
    Referenz
    Produkbestellnummer:
    07-753
    Produktbezeichnung:
    Anti-RIAP-3 (XIAP) Antibody

  • HDAC inhibitors restore the capacity of aged mice to respond to haloperidol through modulation of histone acetylation. 24366052

    Antipsychotic drugs are widely prescribed to elderly patients for the treatment of a variety of psychopathological conditions, including psychosis and the behavioral disturbances associated with dementia. However, clinical experience suggests that these drugs may be less efficacious in the elderly individuals than in the young. Recent studies suggest that aging may be associated with epigenetic changes and that valproic acid (VPA), a histone deacetylase inhibitor, may reverse such changes. However, it is not yet known whether HDAC inhibitors can modulate age-related epigenetic changes that may impact antipsychotic drug action. In this study, we analyzed conditioned avoidance response (CAR) and c-Fos expression patterns to elucidate the effect of HDAC inhibitors VPA and entinostat (MS-275) on behavioral and molecular markers of the effects of haloperidol (HAL) in aged mice. Our results showed that HAL administration failed to suppress the avoidance response during the CAR test, suggesting an age-related decrease in drug efficacy. In addition, HAL-induced c-Fos expression in the nucleus accumbens shell and prefrontal cortex was significantly lower in aged mice as compared with young mice. Pretreatment with VPA and MS-275 significantly improved HAL effects on the CAR test in aged mice. Also, VPA and MS-275 pretreatment restored HAL-induced increases in c-Fos expression in the nucleus accumbens shell and prefrontal cortex of aged mice to levels comparable with those observed in young mice. Lastly, but most importantly, increases in c-Fos expression and HAL efficacy in the CAR test of the HAL+VPA and HAL+MS-275 groups were correlated with elevated histone acetylation at the c-fos promoter region in aged mice. These findings suggest that pretreatment with VPA or MS-275 increases the behavioral and molecular effects of HAL in aged mice and that these effects occur via modulation of age-related histone hypoacetylation in the nucleus accumbens shell and prefrontal cortex.
    Dokumententyp:
    Referenz
    Produkbestellnummer:
    17-20000
    Produktbezeichnung:
    Magna ChIP™ G Tissue Kit

  • Monoclonal antibodies directed to different regions of vascular endothelial cadherin extracellular domain affect adhesion and clustering of the protein and modulate endot ... 11238107

    Vascular endothelial cadherin (VE-cadherin) is an endothelial cell-specific cadherin that plays an important role in the control of vascular organization. Blocking VE-cadherin antibodies strongly inhibit angiogenesis, and inactivation of VE-cadherin gene causes embryonic lethality due to a lack of correct organization and remodeling of the vasculature. Hence, inhibitors of VE-cadherin adhesive properties may constitute a tool to prevent tumor neovascularization. In this paper, we tested different monoclonal antibodies (mAbs) directed to human VE-cadherin ectodomain for their functional activity. Three mAbs (Cad 5, BV6, BV9) were able to increase paracellular permeability, inhibit VE-cadherin reorganization, and block angiogenesis in vitro. These mAbs could also induce endothelial cell apoptosis in vitro. Two additional mAbs, TEA 1.31 and Hec 1.2, had an intermediate or undetectable activity, respectively, in these assays. Epitope mapping studies show that BV6, BV9, TEA 1.31, and Hec 1.2 bound to a recombinant fragment spanning the extracellular juxtamembrane domains EC3 through EC4. In contrast, Cad 5 bound to the aminoterminal domain EC1. By peptide scanning analysis and competition experiments, we defined the sequences TIDLRY located on EC3 and KVFRVDAETGDVFAI on EC1 as the binding domain of BV6 and Cad 5, respectively. Overall, these results support the concept that VE-cadherin plays a relevant role on human endothelial cell properties. Antibodies directed to the extracellular domains EC1 but also EC3-EC4 affect VE-cadherin adhesion and clustering and alter endothelial cell permeability, apoptosis, and vascular structure formation.
    Dokumententyp:
    Referenz
    Produkbestellnummer:
    MABT129
    Produktbezeichnung:
    Anti-VE-Cadherin Antibody (CD144), clone BV9

  • Anti-PHF antibodies: an immunohistochemical marker of the lesions of the Alzheimer's disease. Characterization and comparison with Bodian's silver impregnation. 2409667

    An immune serum raised against paired helical filaments (PHF) was able to stain senils plaques (SP) and neurofibrillary tangles (NFT) specifically, the two characteristic lesions of the dementia of Alzheimer-type. This polyclonal antibody against PHF was characterized by immunochemistry and also compared with the classical Bodian silver staining. NFT and SP were observed where they were expected: in the fronto-temporal neo-cortex and hippocampus of Alzheimer-type patients, and also in hippocampus of non-demented elderly subjects. The pattern of SP visualized by the two methods was identical whereas NFT were not detected specifically by silver salts, specially in the nervous tissue where NFT were in discrete quantities. Since the preparation of the antigen is very easy and the resulting antibodies are specific, we conclude that this technique will be of considerable interest for routine neuropathological diagnosis. Finally, the properties of our anti-PHF antibody are compared with those reported in the literature. This antibody will probably be a good tool for the identification of the chemical nature of PHF components.
    Dokumententyp:
    Referenz
    Produkbestellnummer:
    AB1518
    Produktbezeichnung:
    Anti-Neurofibrillary Tangles Antibody

  • HDAC inhibitors act with 5-aza-2'-deoxycytidine to inhibit cell proliferation by suppressing removal of incorporated abases in lung cancer cells. 18560576

    5-Aza-2'-deoxycytidine (5-aza-CdR) is used extensively as a demethylating agent and acts in concert with histone deacetylase inhibitors (HDACI) to induce apoptosis or inhibition of cell proliferation in human cancer cells. Whether the action of 5-aza-CdR in this synergistic effect results from demethylation by this agent is not yet clear. In this study we found that inhibition of cell proliferation was not observed when cells with knockdown of DNA methyltransferase 1 (DNMT1), or double knock down of DNMT1-DNMT3A or DNMT1-DNMT3B were treated with HDACI, implying that the demethylating function of 5-aza-CdR may be not involved in this synergistic effect. Further study showed that there was a causal relationship between 5-aza-CdR induced DNA damage and the amount of [(3)H]-5-aza-CdR incorporated in DNA. However, incorporated [(3)H]-5-aza-CdR gradually decreased when cells were incubated in [(3)H]-5-aza-CdR free medium, indicating that 5-aza-CdR, which is an abnormal base, may be excluded by the cell repair system. It was of interest that HDACI significantly postponed the removal of the incorporated [(3)H]-5-aza-CdR from DNA. Moreover, HDAC inhibitor showed selective synergy with nucleoside analog-induced DNA damage to inhibit cell proliferation, but showed no such effect with other DNA damage stresses such as gamma-ray and UV, etoposide or cisplatin. This study demonstrates that HDACI synergistically inhibits cell proliferation with nucleoside analogs by suppressing removal of incorporated harmful nucleotide analogs from DNA.
    Dokumententyp:
    Referenz
    Produkbestellnummer:
    05-636
    Produktbezeichnung:
    Anti-phospho-Histone H2A.X (Ser139) Antibody, clone JBW301

  • CK2 inhibitors increase the sensitivity of HSV-1 to interferon-β. 21722672

    Herpes simplex virus type 1 (HSV-1) requires the activities of cellular kinases for efficient replication. The host kinase, CK2, has been shown or is predicted to modify several HSV-1 proteins and has been proposed to affect one or more steps in the viral life cycle. Furthermore, potential cellular and viral substrates of CK2 are involved in antiviral pathways and viral counter-defenses, respectively, suggesting that CK2 regulates these processes. Consequently, we tested whether pharmacological inhibitors of CK2 impaired HSV-1 replication, either alone or in combination with the cellular antiviral factor, interferon-β (IFN-β). Our results indicate that the use of CK2 inhibitors results in a minor reduction in HSV-1 replication but enhanced the inhibitory effect of IFN-β on replication. This effect was dependent on the HSV-1 E3 ubiquitin ligase, infected cell protein 0 (ICP0), which impairs several host antiviral responses, including that produced by IFN-β. Inhibitors of CK2 did not, however, impede the ability of ICP0 to induce the degradation of two cellular targets: the promyelocytic leukemia protein (PML) and the DNA-dependent protein kinase catalytic subunit (DNA-PKcs). Notably, this effect was only apparent for HSV-1, as the CK2 inhibitors did not enhance the antiviral effect of IFN-β on either vesicular stomatitis virus or adenovirus type 5. Thus, our data suggest that the activity of CK2 is required for an early function during viral infection that assists the growth of HSV-1 in IFN-β-treated cells.
    Dokumententyp:
    Referenz
    Produkbestellnummer:
    MAB3678
    Produktbezeichnung:
    Anti-Chloramphenicol Acetyltransferase Antibody, clone CAT-1

  • EGFR inhibitors exacerbate differentiation and cell cycle arrest induced by retinoic acid and vitamin D3 in acute myeloid leukemia cells. 23974111

    By means of an unbiased, automated fluorescence microscopy-based screen, we identified the epidermal growth factor receptor (EGFR) inhibitors erlotinib and gefitinib as potent enhancers of the differentiation of HL-60 acute myeloid leukemia (AML) cells exposed to suboptimal concentrations of vitamin A (all-trans retinoic acid, ATRA) or vitamin D (1α,25-hydroxycholecalciferol, VD). Erlotinib and gefitinib alone did not promote differentiation, yet stimulated the acquisition of morphological and biochemical maturation markers (including the expression of CD11b and CD14 as well as increased NADPH oxidase activity) when combined with either ATRA or VD. Moreover, the combination of erlotinib and ATRA or VD synergistically induced all the processes that are normally linked to terminal hematopoietic differentiation, namely, a delayed proliferation arrest in the G0/G1 phase of the cell cycle, cellular senescence, and apoptosis. Erlotinib potently inhibited the (auto)phosphorylation of mitogen-activated protein kinase 14 (MAPK14, best known as p38(MAPK)) and SRC family kinases (SFKs). If combined with the administration of ATRA or VD, the inhibition of p38(MAPK) or SFKs with specific pharmacological agents mimicked the pro-differentiation activity of erlotinib. These data were obtained with 2 distinct AML cell lines (HL-60 and MOLM-13 cells) and could be confirmed on primary leukemic blasts isolated from the circulation of AML patients. Altogether, these findings point to a new regimen for the treatment of AML, in which naturally occurring pro-differentiation agents (ATRA or VD) may be combined with EGFR inhibitors.
    Dokumententyp:
    Referenz
    Produkbestellnummer:
    Mehrere
    Produktbezeichnung:
    Mehrere

  • Monoclonal antibodies distinguish several differentially phosphorylated states of the two largest rat neurofilament subunits (NF-H and NF-M) and demonstrate their existen ... 3119789

    A new panel of greater than 300 monoclonal antibodies (mAbs) was prepared to the high, middle, and low Mr rat neurofilament (NF) subunits (NF-H, NF-M and NF-L, respectively). NF proteins were purified both from native, i.e., phosphorylated rat NFs and from enzymatically dephosphorylated rat NFs. The resulting mAbs were used to biochemically and immunochemically distinguish and characterize distinct and differentially phosphorylated isoforms of NF subunits. By immunoblot, all mAbs specific for NF-L and some mAbs specific for NF-M detected their specific NF subunit regardless of whether or not the NFs had been treated with alkaline phosphatase, and such antibodies were termed "phosphate-independent" or P[ind] mAbs. The other mAbs were specific for NF-M, NF-H, or for both NF-M and NF-H, and they recognized epitopes in the COOH termini of these subunits. Significantly, the latter mAbs could discriminate different isoforms of NF-M and NF-H, depending on the phosphorylation state of each variant. Such mAbs were assigned to one of 4 distinct categories on the basis of their performance in immunoblots of progressively dephosphorylated rat NF samples and by immunohistochemistry of various adult rat nervous tissues: (1) P[-] mAbs preferentially stained neuronal perikarya and dendrites, and they recognized only extensively dephosphorylated (and nonphosphorylated) NF-H; (2) P[+] mAbs stained axons more strongly than perikarya, and primarily blotted phosphorylated, but not nonphosphorylated, forms of NF-H and NF-M; (3) P[++] mAbs stained axons almost to the exclusion of perikarya, and in blots recognized only the extensively phosphorylated forms of NF-H and NF-M (i.e., subunits subjected to limited enzymatic dephosphorylation); (4) P[ ] mAbs also predominantly stained axons, but the briefest alkaline phosphatase treatment abolished the NF-M and NF-H immunobands produced by these mAbs. Two-dimensional gel analysis and immunoblotting of total proteins from adult rat dorsal root ganglion verified mAb specificity in situ, and showed that differentially phosphorylated isoforms of NF-M and NF-H occur in vivo. This provided additional evidence that mAbs can detect all 4 phosphorylation-dependent endogenous isoelectric variants of NF-H and NF-M.(ABSTRACT TRUNCATED AT 400 WORDS)
    Dokumententyp:
    Referenz
    Produkbestellnummer:
    Mehrere
    Produktbezeichnung:
    Mehrere

  • The Ras Inhibitors Caveolin-1 and Docking Protein 1 Activate Peroxisome Proliferator-Activated Receptor {gamma} through Spatial Relocalization at Helix 7 21690289

    Peroxisome proliferator-activated receptor γ (PPARγ) is a transcription factor that promotes differentiation and cell survival in the stomach. PPARγ upregulates and interacts with caveolin-1 (Cav1), a scaffold protein of Ras/mitogen-activated protein kinases (MAPKs). The cytoplasmic-to-nuclear localization of PPARγ is altered in gastric cancer (GC) patients, suggesting a so-far-unknown role for Cav1 in spatial regulation of PPARγ signaling. We show here that loss of Cav1 accelerated proliferation of normal stomach and GC cells in vitro and in vivo. Downregulation of Cav1 increased Ras/MAPK-dependent phosphorylation of serine 84 in PPARγ and enhanced nuclear translocation and ligand-independent transcription of PPARγ target genes. In contrast, Cav1 overexpression sequestered PPARγ in the cytosol through interaction of the Cav1 scaffolding domain (CSD) with a conserved hydrophobic motif in helix 7 of PPARγ\'s ligand-binding domain. Cav1 cooperated with the endogenous Ras/MAPK inhibitor docking protein 1 (Dok1) to promote the ligand-dependent transcriptional activity of PPARγ and to inhibit cell proliferation. Ligand-activated PPARγ also reduced tumor growth and upregulated the Ras/MAPK inhibitors Cav1 and Dok1 in a murine model of GC. These results suggest a novel mechanism of PPARγ regulation by which Ras/MAPK inhibitors act as scaffold proteins that sequester and sensitize PPARγ to ligands, limiting proliferation of gastric epithelial cells.
    Dokumententyp:
    Referenz
    Produkbestellnummer:
    05-368
    Produktbezeichnung:
    Anti-phospho-Ser/Thr-Pro MPM-2 Antibody

  • Serum antibodies critically affect virus-specific CD4+/CD8+ T cell balance during respiratory syncytial virus infections. 20971927

    Following infection with respiratory syncytial virus (RSV), reinfection in healthy individuals is common and presumably due to ineffective memory T cell responses. In peripheral blood of healthy adults, a higher CD4(+)/CD8(+) memory T cell ratio was observed compared with the ratio of virus-specific effector CD4(+)/CD8(+) T cells that we had found in earlier work during primary RSV infections. In mice, we show that an enhanced ratio of RSV-specific neutralizing to nonneutralizing Abs profoundly enhanced the CD4(+) T cell response during RSV infection. Moreover, FcγRs and complement factor C1q contributed to this Ab-mediated enhancement. Therefore, the increase in CD4(+) memory T cell response likely occurs through enhanced endosomal Ag processing dependent on FcγRs. The resulting shift in memory T cell response was likely amplified by suppressed T cell proliferation caused by RSV infection of APCs, a route important for Ag presentation via MHC class I molecules leading to CD8(+) T cell activation. Decreasing memory CD8(+) T cell numbers could explain the inadequate immunity during repeated RSV infections. Understanding this interplay of Ab-mediated CD4(+) memory T cell response enhancement and infection mediated CD8(+) memory T cell suppression is likely critical for development of effective RSV vaccines.
    Dokumententyp:
    Referenz
    Produkbestellnummer:
    MAB858-2-5
    Produktbezeichnung:
    Anti-RSV Antibody, glycoprotein, all type A, B strains, clone 131-2G