Interaction of tacrolimus ( FK506 ) and its metabolites with FKBP and calcineurin .
DB00864
SUB
( FK506 ) is a strong immuno-suppressant and shows its activity through inhibiting
P60568
REA
mRNA transcription by forming pentameric complex with intracellular receptor ( FK506 binding protein 12 kDa or
P62942
REA
) , Ca2 + , calmodulin , and calcineurin . Here , we report the binding activity to
P62942
REA
, the pentameric complex formation and Con-A response inhibiting activities of 7 metabolites . C15 - demethylated metabolite ( M - 3 ) needed higher quantity to compete in Con-A assay and in pentamer formation assay , although it binds more strongly to
P62942
REA
. The result suggests that the ability to form a pentameric complex is not a two step reaction with the first binding to
P62942
REA
, but a single step reaction by components for the pentamer formation .
1
Structure and function of eritadenine and its 3 - deaza analogues : potent inhibitors of S-adenosylhomocysteine hydrolase and hypocholesterolemic agents . d -
DB03769
MEN
( DEA ) is a potent inhibitor of S-adenosyl-l-homocysteine hydrolase (
P23526
REA
) and has hypocholesterolemic activity . We have hypothesized that 3 - deaza-DEA (
P01024
REA
- DEA ) and its analogues retain high level of
P23526
REA
inhibitory activity and have resistance to deamination and glycosidic bond hydrolysis in vivo . Such
P01024
REA
- DEA analogues would have much higher hypocholesterolemic activity .
P01024
REA
- DEA , and its methyl ester (
P01024
REA
- OMeDEA ) and its methyl amido (
P01024
REA
- NMeDEA ) were synthesized to examine their
P23526
REA
inhibitory and hypocholesterolemic activities . A crystal structure of
P23526
REA
containing
P01024
REA
- DEA was determined and confirmed that DEA and
P01024
REA
- DEA bound to the same site of
P23526
REA
with the same binding mode . The
P23526
REA
inhibitory activities of
P01024
REA
- DEA ( K ( I )= 1.5 microM ) and
P01024
REA
- OMeDEA ( K ( I )= 1.5 microM ) are significantly lower than that of DEA ( K ( I )= 30 nM ) , while rats fed by
P01024
REA
- DEA and
P01024
REA
- OMeDEA decrease the total plasma cholesterol and phospholipids by 36-40 % and 23 % , respectively , which is similar to the level of reductions ( 42 % and 27 % ) by DEA .
P01024
REA
- NMeDEA lost most of the
P23526
REA
inhibitory activity ( K ( I )= 30 microM ) and dietary
P01024
REA
- NMeDEA does not decrease cholesterol and phospholipid in plasma but decreases the triacylglycerol level by 16 % . DEA and
P01024
REA
- DEA analogues are neither substrates nor inhibitors of adenosine deaminase .
2
Effects of antihistamines on the function of human α7 - nicotinic acetylcholine receptors . Effects of the histamine H₁ receptor (
P35367
REA
) antagonists ( antihistamines ) , promethazine ( PMZ ) , orphenadrine ( ORP ) , chlorpheniramine ( CLP ) ,
DB06691
MEN
( PYR ) , diphenhydramine ( DPH ) , citerizine ( CTZ ) , and triprolidine ( TRP ) on the functional properties of the cloned α7 subunit of the human nicotinic acetylcholine receptor expressed in Xenopus oocytes were investigated . Antihistamines inhibited the α7 - nicotinic acetylcholine receptor in the order PYR > CLP > TRP > PMZ > ORP ≥ DPH ≥ CTZ . Among the antihistamines , PYR showed the highest reversible inhibition of acetylcholine ( 100 µM ) - induced responses with IC₅₀ of 6.2 µM . PYR-induced inhibition was independent of the membrane potential and could not be reversed by increasing the concentration of acetylcholine . Specific binding of [ ¹²⁵I ] α-bungarotoxin , a selective antagonist for α7 - nicotinic acetylcholine receptor , was not changed in the presence of PYR suggesting a non-competitive inhibition of nicotinic receptors . In line with functional experiments , docking studies indicated that PYR can potentially bind allosterically with the α7 transmembrane domain . Our results indicate that the H₂-H₄ receptor antagonists tested in this study ( 10 µM ) showed negligible inhibition of α7 - nicotinic acetylcholine receptors . On the other hand , H₁ receptor antagonists inhibited the function of human α7 - nicotinic acetylcholine receptor , with varying potencies . These results emphasize the importance of α7 - nicotinic acetylcholine receptor for future pharmacological / toxicological profiling .
3
[ The importance of determination of interleukin - 10 in the blood of patients with systemic lupus erythematosus ] . BACKGROUND : Hitherto , not very numerous investigations provided so far only few often controversial findings on the importance of interleukin - 10 (
P22301
REA
) in systemic lupus erythematosus ( SLE ) . The objective of the present investigation was to assess whether there exist practically applicable relations between the serum level of
P22301
REA
, clinical and laboratory indicators of activity of the disease and serum levels of selected cytokines or their soluble receptors . METHODS AND RESULTS : The authors analyzed a group of 23 patients with SLE ( 23 women and 1 man , median age 37 years ) .
P22301
REA
and other cytokines were examined by the ELISA method , the clinical activity of the disease was evaluated by the ECLAM system ( European Consensus Lupus Activity Measurement ) . Elevated
P22301
REA
values ( > 5 pg / ml ) were assessed in 10 ( 43 % ) patients . Correlation analysis ( Pearson ' s test , p < 0.05 ) revealed statistically significant relations between
P22301
REA
levels and the activity of the disease , values of antibody levels against dsDNA and levels of the soluble receptor
P60568
REA
( sIL - 2R ) in serum . Conversely , no relationship was revealed between values of
P22301
REA
and values of
P01024
REA
and C4 complement components , IL - 1 ,
P60568
REA
,
P05231
REA
, sIL - 6R ,
P01375
REA
, sTNFR-alpha and
P27352
REA
- gamma . CONCLUSIONS : Elevated
P22301
REA
serum levels in patients with SLE did not have , with the exception of the index of clinical activity of the disease , antibodies against dsDNA and sIL - 2R any statistically significant relations to laboratory indicators of disease activity and levels of selected cytokines and their soluble receptors .
4
Korean Red
DB01404
MEN
Extract Attenuates 3 - Nitropropionic Acid-Induced Huntington's-Like Symptoms . Korean red ginseng ( KRG ) possesses neuroprotective activity . However , the potential neuroprotective value of KRG for the striatal toxicity is largely unknown . We investigated whether KRG extract ( KRGE ) could have a neuroprotective effect in a 3 - nitropropionic acid - ( 3 - NP ) induced ( i . p . ) Huntington ' s disease ( HD ) model . KRGE ( 50 , 100 , and 250 mg / kg / day , p . o . ) was administrated 10 days before 3 - NP injection ( pre-administration ) , from the same time with 3 - NP injection ( co-administration ) , or from the peak point of neurological impairment by 3 - NP injection ( post-administration ) . Pre-administration of KRGE produced the greatest neuroprotective effect in this model . Pre-administration of KRGE significantly decreased 3 - NP-induced neurological impairment , lethality , lesion area , and neuronal loss in the 3 - NP-injected striatum . KRGE attenuated microglial activation and phosphorylation of mitogen-activated protein kinases ( MAPKs ) and nuclear factor-kappa B ( NF-κB ) signal pathway . KRGE also reduced the level of mRNA expression of tumor necrosis factor-alpha , interleukin - ( IL - ) 1β ,
P05231
REA
, inducible nitric oxide synthase , and OX - 42 . Interestingly , the intrathecal administration of SB203580 ( a p38 inhibitor ) or PD98059 ( an inhibitor of MAPK Kinase , MEK ) increased the survival rate in the 3 - NP-induced HD model . Pre-administration of KRGE may effectively inhibit 3 - NP-induced striatal toxicity via the inhibition of the phosphorylation of MAPKs and NF-κB pathways , indicating its therapeutic potential for suppressing Huntington's-like symptoms .
5
Gene-based vaccines and immunotherapeutics . DNA vaccines , comprised of plasmid DNA encoding proteins from pathogens , allergens , and tumors , are being evaluated as prophylactic vaccines and therapeutic treatments for infectious diseases , allergies , and cancer ; plasmids encoding normal human proteins are likewise being tested as vaccines and treatments for autoimmune diseases . Examples of in vivo prophylaxis and immunotherapy , based on different types of immune responses ( humoral and cellular ) , in a variety of disease models and under evaluation in early phase human clinical trials are presented . Viral vectors continue to show better levels of expression than those achieved by DNA plasmid vectors . We have focused our clinical efforts , at this time , on the use of recombinant viral vectors for both vaccine as well as cytokine gene transfer studies . We currently have four clinical programs in cancer immunotherapy . Two nonspecific immunotherapy programs are underway that apply adenoviral vectors for the transfer of cytokine genes into tumors in situ . An adenovirus-IFN gamma construct ( TG1042 ) is currently being tested in phase II clinical trials in cutaneous lymphoma . A similar construct , adenovirus -
P60568
REA
( TG1024 ) , also injected directly into solid tumors , is currently being tested in patients with solid tumors ( about one-half of which are melanoma ) . Encouraging results are seen in both programs . Two cancer vaccine immunotherapy programs focus on two cancer-associated antigens : human papilloma virus E6 and E7 proteins and the epithelial cancer-associated antigen
P15941
REA
. Both are encoded by a highly attenuated vaccinia virus vector [ modified vaccinia Ankara ( MVA ) ] and both are coexpressed with
P60568
REA
. Encouraging results seen in both of these programs are described .
6
Displacement of
Q01826
REA
- bound histone deacetylase 1 corepressor by the human immunodeficiency virus type 1 transactivator induces expression of interleukin - 2 and its receptor in T cells . One hallmark of human immunodeficiency virus type 1 ( HIV - 1 ) infection is the dysregulation of cytokine gene expression in T cells . Transfection of T cells with human T-cell leukemia type 1 or 2 transactivator results in the induction of the T-cell-restricted cytokine interleukin - 2 (
P60568
REA
) and its receptor ( IL - 2Ralpha ) . However , no T-cell-specific factor ( s ) has been directly linked with the regulation of
P60568
REA
and IL - 2Ralpha transcription by influencing the promoter activity . Thymocytes from
Q01826
REA
( special AT-rich sequence binding protein 1 ) knockout mice have been shown to ectopically express IL - 2Ralpha , suggesting involvement of
Q01826
REA
in its negative regulation . Here we show that
Q01826
REA
, a T-cell-specific global gene regulator , binds to the promoters of human
P60568
REA
and IL - 2Ralpha and recruits histone deacetylase 1 (
Q13547
REA
) in vivo .
Q01826
REA
also interacts with Tat in HIV - 1 - infected T cells . The functional interaction between HIV - 1 Tat and
Q01826
REA
requires its PDZ-like domain , and the binding of the
Q13547
REA
corepressor occurs through the same . Furthermore , Tat competitively displaces
Q13547
REA
that is bound to
Q01826
REA
, leading to increased acetylation of the promoters in vivo . Transduction with
Q01826
REA
interaction-deficient soluble Tat ( Tat 40-72 ) and reporter assays using a transactivation-negative mutant ( C22G ) of Tat unequivocally demonstrated that the displacement of
Q13547
REA
itself is sufficient for derepression of these promoters in vivo . These results suggest a novel mechanism by which HIV - 1 Tat might overcome
Q01826
REA
- mediated repression in T cells .
7
P40189
REA
- linked signal transduction promotes the differentiation and maturation of dendritic cells . In order to explore the role of
P40189
REA
- linked signal transduction in the differentiation and maturation of dendritic cells ( DC ) , the mAb , B -
P28222
REA
, an agonist of
P40189
REA
, was used for the activation of
P40189
REA
on DC . The effects of cytokines and of anti -
P40189
REA
mAb on the proliferation of DC , and their expression of IL - 12 and
P33681
REA
(
P33681
REA
- 1 ) by DC were evaluated . DC differentiating from peripheral blood mononuclear cells did not express the
P05231
REA
receptor alpha chain , but expressed
P40189
REA
. Anti -
P40189
REA
mAb promoted the proliferation of DC , induced by
P05112
REA
and granulocyte macrophage colony stimulating factor ( GM -
P04141
REA
) , by up-regulating the GM -
P04141
REA
receptor on DC . DC induced by
P40189
REA
mAb and cytokines expressed DC-derived CC chemokine , as measured by RT-PCR . Induced DC also stimulated strong proliferation of autologous T cells in mixed lymphocyte reaction since an up-regulated expression of IL - 12 and
P33681
REA
(
P33681
REA
- 1 ) was observed in DC activated by anti -
P40189
REA
mAb . Thus ,
P40189
REA
signal transduction is important for the differentiation and maturation of DC .
8
Synteny mapping in the bovine : genes from human chromosome 4 . Genes homologous to those located on human chromosome 4 ( HSA 4 ) were mapped in the bovine to determine regions of syntenic conservation among humans , mice , and cattle . Previous studies have shown that two homologs of genes on HSA 4 ,
Q96G03
REA
and P28838 , are located in bovine syntenic group U15 ( chromosome 6 ) . The homologous mouse genes , Pgm - 1 and Pep - 7 , are on MMU 5 . Using a panel of bovine x hamster hybrid somatic cells , we have assigned homologs of 11 additional HSA 4 loci to their respective bovine syntenic groups . D4S43 , D4S10 ,
P09417
REA
,
P01591
REA
,
P00325
REA
,
P10721
REA
, and IF were assigned to syntenic group U15 . This syntenic arrangement is not conserved in the mouse , where D4s43 , D4s10 , Qdpr , and Igj are on MMU 5 while Adh - 2 is on MMU 3 .
P60568
REA
,
P02675
REA
,
P02679
REA
, and
P03951
REA
, which also reside on MMU 3 , were assigned to bovine syntenic group U23 . These data suggest that breaks and / or fusions of ancestral chromosomes carrying these genes occurred at different places during the evolution of humans , cattle , and mice .
9
Integrin alpha 5 - induced
P00533
REA
activation by prothrombin triggers hepatocyte apoptosis via the JNK signaling pathway . We have previously shown that prothrombin , a blood coagulation factor , can cause an inhibition of DNA synthesis in normal rat hepatocytes . To explore the mechanisms of this prothrombin action , we examined its effects on the activation of fibronectin receptor integrin alpha 5 , since fibronectin was found to be degraded by prothrombin actions in primary hepatocyte cultures . We found that prothrombin treatment of rat hepatocytes without addition of any growth factor induced tyrosine phosphorylation of integrin alpha 5 and interaction of integrin alpha 5 with epidermal growth factor receptor (
P00533
REA
) , leading to
P00533
REA
tyrosine phosphorylation at tyrosine residues DB00135 - 845 and DB00135 - 1173 .
P00533
REA
tyrosine phosphorylation triggered phosphorylation of its down-stream target Shc and the activation of the c-Jun N-terminal kinase ( JNK ) pathway .
P00734
REA
also induced hepatocyte apoptosis , a change in cell shape and activation of caspase 3 pathway . The JNK pathway is most likely involved in prothrombin-induced hepatocyte apoptosis , because pre-treatment of hepatocytes with JNK kinase inhibitor II ( SP600125 ) antagonized these prothrombin actions . The data suggest that integrin-related
P00533
REA
activation by prothrombin can induce cell growth inhibition and apoptosis via an
P00533
REA
- JNK signaling pathway .
10
Meta-analysis of oral DB00669 therapy for migraine : number needed to treat and relative cost to achieve relief within 2 hours . OBJECTIVE : To determine the cost-effectiveness of the
P28222
REA
/ 1D agonists , or triptans , in the acute treatment of migraine . METHODS : To determine the cost-effectiveness of the triptans , a meta-analysis was conducted of the efficacy data from 27 oral DB00669 trials , using the endpoint of " pain-free " status within 2 hours after initial dosing as the indicator of efficacy . Efficacy data were used to determine the number needed to treat (
Q13423
REA
) to achieve pain-free status in 1 patient within 2 hours postdose and then applied the per-dose costs for each DB00669 to the
Q13423
REA
values . RESULTS : Rizatriptan 10 mg and almotriptan 12.5 mg were the most cost-effective of the triptans , costing $ 48.34 and $ 48.57 US dollars , respectively , to achieve pain-free status in 1 patient within 2 hours postdose .
DB00998
MEN
2.5 mg was the most costly , with a cost-effective ratio of $ 162.49 US dollars . All other triptans fell between these extremes : zolmitriptan 5 mg ( $ 65.18 US dollars ) , sumatriptan 100 mg ( $ 70.83 US dollars ) , sumatriptan 50 mg ( $ 75.67 US dollars ) , zolmitriptan 2.5 mg ( $ 78.74 US dollars ) , and naratriptan 2.5 mg ( $ 141.43 US dollars ) , in decreasing order of cost-effectiveness . CONCLUSION : Using an
Q13423
REA
analysis , the least-costly drugs to achieve migraine cure within 2 hours are rizatriptan 10 mg and almotriptan 12.5 mg . From a population health perspective , the lower acquisition cost of almotriptan 12.5 mg allows for effective treatment of more patients than rizatriptan 10 mg for no additional medication cost .
11
Generation of Epstein-Barr virus-specific cytotoxic T lymphocytes resistant to the immunosuppressive drug tacrolimus ( FK506 ) . Adoptive transfer of autologous Epstein-Barr virus-specific cytotoxic T lymphocytes ( EBV-CTLs ) to solid organ transplant ( SOT ) recipients has been shown safe and effective for the treatment of EBV-associated posttransplantation lymphoproliferative disorders ( PTLDs ) . SOT recipients , however , require the continuous administration of immunosuppressive drugs to prevent graft rejection , and these agents may significantly limit the long-term persistence of transferred EBV-CTLs , precluding their use as prophylaxis .
DB00864
SUB
( FK506 ) is one of the most widely used immunosuppressive agents in SOT recipients , and its immunosuppressive effects are largely dependent on its interaction with the 12 - kDa FK506 - binding protein (
P62942
REA
) . We have knocked down the expression of
P62942
REA
in EBV-CTLs using a specific small interfering RNA ( siRNA ) stably expressed from a retroviral vector and found that
P62942
REA
- silenced EBV-CTLs are FK506 resistant . These cells continue to expand in the presence of the drug without measurable impairment of their antigen specificity or cytotoxic activity . We confirmed their FK506 resistance and anti-PTLD activity in vivo using a xenogenic mouse model , suggesting that the proposed strategy may be of value to enhance EBV-specific immune surveillance in patients at high risk of PTLD after transplantation .
12
Role of xanthine oxidoreductase and NAD ( P ) H oxidase in endothelial superoxide production in response to oscillatory shear stress . Oscillatory shear stress occurs at sites of the circulation that are vulnerable to atherosclerosis . Because oxidative stress contributes to atherosclerosis , we sought to determine whether oscillatory shear stress increases endothelial production of reactive oxygen species and to define the enzymes responsible for this phenomenon . Bovine aortic endothelial cells were exposed to static , laminar ( 15 dyn / cm2 ) , and oscillatory shear stress ( + / - 15 dyn / cm2 ) . Oscillatory shear increased superoxide ( O2 . - ) production by more than threefold over static and laminar conditions as detected using electron spin resonance (
P03372
REA
) . This increase in O2 * - was inhibited by oxypurinol and culture of endothelial cells with tungsten but not by inhibitors of other enzymatic sources .
DB05262
MEN
also prevented H2O2 production in response to oscillatory shear stress as measured by dichlorofluorescin diacetate and Amplex Red fluorescence . DB02134 - dependent O2 * - production was increased in homogenates of endothelial cells exposed to oscillatory shear stress . This was associated with decreased xanthine dehydrogenase (
P47989
REA
) protein levels and enzymatic activity resulting in an elevated ratio of xanthine oxidase ( XO ) to
P47989
REA
. We also studied endothelial cells lacking the p47phox subunit of the NAD ( P ) H oxidase . These cells exhibited dramatically depressed O2 * - production and had minimal XO protein and activity . Transfection of these cells with p47phox restored XO protein levels . Finally , in bovine aortic endothelial cells , prolonged inhibition of the NAD ( P ) H oxidase with apocynin decreased XO protein levels and prevented endothelial cell stimulation of O2 * - production in response to oscillatory shear stress . These data suggest that the NAD ( P ) H oxidase maintains endothelial cell XO levels and that XO is responsible for increased reactive oxygen species production in response to oscillatory shear stress .
13
DB08875 (
DB05153
MEN
) for the treatment of locally advanced or metastatic progressive medullary thyroid cancer . DB08875 (
DB05153
MEN
) is an oral multiple receptor tyrosine kinase inhibitor manufactured by Exelixis Inc . , CA , USA . It mainly inhibits three tyrosine kinase receptors : MET ,
P35968
REA
and
P07949
REA
. In both preclinical and clinical studies it has been shown to inhibit tumor angiogenesis , invasiveness and metastases . The most frequent side effects are fatigue , diarrhea , decreased appetite , nausea , weight loss and palmar-plantar erythrodysesthesia . A Phase III clinical trial ( EXAM study ) of
DB05153
MEN
versus placebo in advanced and progressive medullary thyroid cancer showed a 28 versus 0 % overall response rate and a progression-free survival of 11.2 versus 4.0 months ( hazard ratio : 0.28 ; 95 % CI : 0.19- 0.40 ; p < 0.0001 ) in patients treated with cabozantinib and placebo , respectively . The drug has been approved by the US FDA for the treatment of advanced / progressive metastatic medullary thyroid cancer in the USA . The
P15941
REA
is now evaluating its approval in Europe .
14
Forced dimerization increases the activity of Δ
P00533
REA
/ EGFRvIII and enhances its oncogenicity . Delta epidermal growth factor receptor ( Δ
P00533
REA
) , an in-frame deletion mutant of the extracellular ligand-binding domain , which occurs in about 30 % of glioblastoma , is a potent oncogene that promotes tumor growth and progression . The signaling of Δ
P00533
REA
is ligand-independent and low intensity , allowing it to evade the normal mechanisms of internalization and degradation by the endocytic machinery and hence is persistent . The basis of the oncogenic potential of Δ
P00533
REA
remains incompletely understood , including whether dimerization plays an important role in its signal and whether its oncogenic potential is dependent on its relatively low intensity , when compared with the acutely activated wild-type receptor . To examine these two important questions , we have generated a chimeric Δ
P00533
REA
that allows forced dimerization via domains derived from variants of the
P62942
REA
protein that are brought together by FK506 derivatives . Forced dimerization of chimeric Δ
P00533
REA
significantly increased the intensity of its signal , as measured by receptor phosphorylation levels , suggesting that the naturally occurring Δ
P00533
REA
does not form strong or stable dimers as part of its low level signal . Interestingly , the increased activity of dimerized , chimeric Δ
P00533
REA
did not promote receptor internalization , implying that reduced rate of endocytic downregulation of Δ
P00533
REA
is an inherent characteristic . Significantly , forced dimerization enhanced the oncogenic signal of the receptor , implying that the Δ
P00533
REA
is a potent oncogene despite , not because of its low intensity .
15
Interpretation of point-of-care INR results in patients treated with dabigatran . BACKGROUND : Point-of-care devices for measurement of the international normalized ratio ( INR ) are commonly used to monitor therapy and maintain therapeutic levels of anticoagulation in patients treated with vitamin K antagonists .
DB06695
MENMAX
DB06695
MEN
, a new oral , reversible direct thrombin inhibitor approved for stroke prevention in patients with atrial fibrillation does not require routine coagulation monitoring . However , case reports have identified falsely elevated point-of-care INR levels in patients treated with dabigatran using one of these devices ( Hemochron ) . This in vitro study was designed to verify this issue . METHODS : We compared INR levels in whole blood and plasma using a Hemochron Jr . Signature + point-of-care device ( International Technidyne Corporation , Edison , NJ ) with routine laboratory monitoring , using blood from healthy volunteers that was spiked with increasing concentrations of dabigatran . RESULTS :
P00734
REA
time and INR levels were increased about 2 - to 4 - fold with the point-of-care device compared with laboratory measures across the plasma dabigatran concentration range 50-1400 ng / mL . At plasma concentrations of dabigatran likely to be observed in patients , at a dose of 150 mg twice daily ( 60-275 ng / mL ) , whole blood point-of-care INR values increased from 1.7 to 4.0 , versus 1.1 to 1.5 measured with the laboratory coagulometer . Similar differences in prothrombin time were observed in plasma samples . CONCLUSIONS : INR levels in patients taking dabigatran are substantially higher using a Hemochron Jr . point-of-care device compared with laboratory values . We discourage the use of these devices specifically , as well as the use of the INR in general , for measuring the anticoagulant effect of dabigatran .
16
Oxidation of alcohols and reduction of aldehydes derived from methyl - and dimethylpyrenes by cDNA-expressed human alcohol dehydrogenases . Some methylated pyrenes can form DNA adducts in rat tissues after benzylic hydroxylation and sulpho conjugation . However , oxidation of the intermediate alcohols to carboxylic acids is an important competing pathway leading to detoxification . We previously showed that co-administration of ethanol or
DB01213
MEN
strongly enhances DNA adduct formation by 1 - hydroxymethylpyrene , indicating an involvement of alcohol dehydrogenases ( ADHs ) in the detoxification . This mechanism may be involved in the observed synergism of smoking and alcohol consumption in certain human cancers . In a preceding study , cDNA-expressed human
P00325
REA
efficiently oxidised 1 - , 2 - and 4 - hydroxymethylpyrene ; these reactions were inhibited in the presence of ethanol or
DB01213
MEN
. Here we report that
P00326
REA
,
P00326
REA
and
P08319
REA
also show substantial activity towards these substrates and two further congeners , 1 - hydroxymethyl - 6 - methylpyrene and 1 - hydroxymethyl - 8 - methylpyrene . All four DB00067 forms also catalysed the reverse reaction , implying that the aldehydes have to be sequestered by other enzymes , such as aldehyde dehydrogenases , for final detoxification .
P00326
REA
and
P08319
REA
activities towards hydroxymethylpyrenes were more strongly inhibited in the presence of ethanol and
DB01213
MEN
than those of
P00325
REA
.
P00326
REA
was only inhibited at very high concentrations of the modulators . In conclusions , several human ADHs are capable of detoxifying benzylic alcohols of alkylated polycyclic aromatic hydrocarbons . However , some competing substrates and inhibitors may affect all these redundant detoxification systems , although to various extents .
17
Induction of differentiation and apoptosis in leukaemic cell lines by the novel benzamide family histone deacetylase 2 and 3 inhibitor MI - 192 . Histone deacetylase inhibitors ( HDACIs ) are in advanced clinical development as cancer therapeutic agents . However , first generation HDACIs such as butyrate and valproate are simple short chain aliphatic compounds with moieties resembling acetyl groups , and have a broad spectrum of activity against HDACs . More complex second generation HDACIs undergoing clinical trials , such as the benzamide group compounds MS - 275 and
DB05651
MEN
, are specific primarily for
Q13547
REA
and
Q92769
REA
. To expand the repertoire of available HDACIs and HDAC specificities we created a novel benzamide-based compound named MI - 192 . When tested against purified recombinant HDACs , MI - 192 had marked selectivity for the class I enzymes ,
Q92769
REA
and
O15379
REA
. Screening in the NCI 60 screen demonstrated that MI - 192 had greatly enhanced efficacy against cells of leukaemic origin . When tested in culture against the acute myeloid leukaemic cell lines U937 , HL60 and Kasumi - 1 , MI - 192 induced differentiation and was cytotoxic through promotion of apoptosis . MI - 192 therefore justifies further investigation and development as a potential therapeutic agent for use in leukaemia .
18
Human epidermal Langerhans ' cells are targets for the immunosuppressive macrolide tacrolimus ( FK506 ) . BACKGROUND : The immunosuppressive macrolide tacrolimus ( FK506 ) has been shown to inhibit allergic contact dermatitis in animal models as well as in human beings . More recently , successful treatment of atopic dermatitis with an ointment containing tacrolimus has been reported . OBJECTIVES : We explored the effects of this compound on epidermal Langerhans ' cells ( LCs ) , which are known to play an important pathophysiologic role in inflammatory skin diseases . METHODS : The expression of the intracellular FK506 binding protein (
P62942
REA
) was monitored on freshly isolated and cultured epidermal LCs . Phenotyping and functional exploration of LCs treated with different concentrations of tacrolimus and beta-methasone valerate ( betaMv ) were performed . RESULTS :
P62942
REA
is expressed in freshly isolated LCs but is lost while they are maturating into mature dendritic cells .
DB00864
SUB
inhibited the expression of IL - 2R ( CD25 ) and of the costimulatory molecules
P33681
REA
(
P33681
REA
. 1 ) and
P25942
REA
. Expression of MHC class I and II was also affected , whereas
P42081
REA
(
P33681
REA
. 2 ) expression was not altered . In contrast , betaMv strongly increased the expression of CD25 . Paradoxically , while decreasing
P25942
REA
and MHC class I expression , betaMv significantly increased the expression of MHC class II ,
P33681
REA
, and
P42081
REA
on cultured LCs but impaired their allostimulatory activity .
DB00864
SUB
was about 100 times more potent than betaMv at inhibiting LC stimulatory function . CONCLUSION :
DB00864
SUB
can exert immunopharmacologic alterations on LCs , which may account , at least in part , for the therapeutic effect of this compound in eczematous skin diseases .
19
The complex of FK506 - binding protein 12 and FK506 inhibits calcineurin phosphatase activity and IgE activation-induced cytokine transcripts , but not exocytosis , in mouse mast cells . FK506 and cyclosporin A ( DB00091 ) are immunosuppressive agents that inhibit
P60568
REA
production by activated T cells , but only DB00091 inhibits IgE activation-induced cytokine transcripts in mouse
P08700
REA
- dependent , bone marrow-derived mast cells ( BMMC ) . We previously associated the resistance of BMMC to FK506 with a deficiency in the expression of FK506 binding protein ( FKBP ) 12 , a molecule that forms a complex with FK506 capable of inhibiting calcineurin phosphatase activity in vitro . In this report , we establish that
P62942
REA
mediates FK506 inhibition of both calcineurin phosphatase activity and IgE activation-induced cytokine transcripts in a Kirsten murine sarcoma virus-immortalized mast cell line that is
P62942
REA
deficient . Overexpression of
P62942
REA
by transfection enhanced the ability of FK506 to inhibit calcineurin phosphatase activity ( IC50 = 2 nM ) , compared with cells transfected with the expression vector alone ( IC50 > 30 nM ) . The IC50 value for FK506 inhibition of IgE activation-induced transcripts for
P01375
REA
decreased from 40 nM in vector control cells to 10 nM in
P62942
REA
transfectants . Similarly , the IC50 value for inhibition of
P05231
REA
transcripts decreased from > 1000 nM in vector control cells to 35 nM in
P62942
REA
transfectants . In contrast , activation-elicited release of the secretory granule mediator beta-hexosaminidase was only partially inhibited by FK506 at 1000 nM , regardless of the levels of
P62942
REA
expressed by the cells . Thus ,
P62942
REA
is the dominant cytosolic protein that mediates FK506 inhibition of
P01375
REA
and
P05231
REA
transcripts .
20
Regulation of Con A-dependent cytokine production from
P01730
REA
+ and CD8 + T lymphocytes by autosecretion of histamine . OBJECTIVES : Previously we have shown that both
P01730
REA
+ T cells and CD8 + T cells produce histamine when activated with Con A . The aim of this study was to examine whether cytokine production by these cells is regulated by autosecretion of histamine . MATERIALS :
P01730
REA
+ and CD8 + T cells were separated from spleen cells of C57BL / 6 mice and mice lacking the H1 receptor (
P35367
REA
) or
P25021
REA
, using anti -
P01730
REA
+ - and anti-CD 8 + - coupled magnetic beads , respectively . RESULTS : Depletion of the
P35367
REA
resulted in decreases in the release of
P60568
REA
and
P22301
REA
from both
P01730
REA
+ and CD8 + cells and increases in the release of
P05112
REA
from
P01730
REA
+ T cells and
P01579
REA
from CD8 + cells . Mice lacking the
P25021
REA
showed up-regulation of
P01579
REA
secretion from CD8 + cells and of
P05112
REA
from
P01730
REA
+ and CD8 + T cells . Release of
P60568
REA
and
P22301
REA
from
P01730
REA
+ as well as CD8 + cells was down-regulated in these mice . Both
P01730
REA
+ and CD8 + T cell fractions synthesized histamine , which was enhanced in the
P35367
REA
- deficient CD8 + T cells . Treatment of the cells with alpha-fluoromethyl-histidine , a specific inhibitor of HDC , or histaminase increased
P01579
REA
from CD8 + cells , whereas it had no appreciable effect on
P05112
REA
secretion from
P01730
REA
+ cells . CONCLUSION : These results suggest that cytokine production by
P01730
REA
+ and CD8 + T lymphocytes is regulated by autosecretion of histamine .
21
DB02134 oxidase inhibitor tungsten prevents the development of atherosclerosis in ApoE knockout mice fed a Western-type diet . Hyperlipidemia enhances xanthine oxidase ( XO ) activity . XO is an important source of reactive oxygen species ( ROS ) . Since ROS are thought to promote atherosclerosis , we hypothesized that XO is involved in the development of atherosclerosis . ApoE ( - / - ) mice were fed a Western-type ( WD ) or control diet . In subgroups , tungsten ( 700 mg / L ) was administered to inhibit XO . XO is a secreted enzyme which is formed in the liver as xanthine dehydrogenase (
P47989
REA
) and binds to the vascular endothelium . High expression of
P47989
REA
was found in the liver and WD increased liver
P47989
REA
mRNA and
P47989
REA
protein expression . WD induced the conversion of
P47989
REA
to the radical-forming XO . Moreover , WD increased the hepatic expression of
P25942
REA
, demonstrating activation of hepatic cells . Aortic tissue of ApoE ( - / - ) mice fed a WD for 6 months exhibited marked atherosclerosis , attenuated endothelium-dependent relaxation to acetylcholine , increased vascular oxidative stress , and mRNA expression of the chemokine KC . Tungsten treatment had no effect on plasma lipids but lowered the plasma XO activity . In animals fed a control diet , tungsten had no effect on radical formation , endothelial function , or atherosclerosis development . In mice fed a WD , however tungsten attenuated the vascular superoxide anion formation , prevented endothelial dysfunction , and attenuated KC mRNA expression . Most importantly , tungsten treatment largely prevented the development of atherosclerosis in the aorta of ApoE ( - / - ) mice on WD . Therefore , tungsten , potentially via the inhibition of XO , prevents the development of endothelial dysfunction and atherosclerosis in ApoE ( - / - ) mice on WD .