Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0021051 (immunodeficiency)
 71,517 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 1.3-kb segment of Escherichia coli DNA containing the regulatory gene, araC, and the promoter of the araBAD operon was amplified by the polymerase chain reaction (PCR) and cloned into pUC18, resulting in plasmid pKB130 that produced the alpha fragment of beta-galactosidase upon addition of L-arabinose (L-ara). A synthetic gene for human immunodeficiency virus (HIV)-1 preprotease was placed downstream of the ara-BAD promoter in pKB130 to create a translational fusion inducible by addition of L-ara. The fusion protein correctly autoprocessed in vivo to yield a mature 99-amino-acid HIV-1 protease, which was found predominantly in inclusion bodies. This material could be refolded to an active form, which was purified to homogeneity. A small fraction of the protease was expressed in vivo as a soluble active form, which allowed the monitoring of expression during fermentation by a rapid and simple whole cell assay employing an HIV-1 protease-specific fluorogenic substrate.
 ...
PMID:High-level expression and purification of mature HIV-1 protease in Escherichia coli under control of the araBAD promoter. 136 41

In this report, we have compared the uptake, metabolism, and relevant enzymology of a novel anti-acquired immunodeficiency syndrome drug, 2'-fluoro-2',3'-dideoxyarabinosyladenine (2'-F-dd-ara-A) with the corresponding properties of its parent compound 2',3'-dideoxyadenosine (2',3'-ddAdo) in three human T cell lines, MOLT-4, ATH8, and CEM. In previous communications, we have reported that the primary route of metabolism of 2',3'-ddAdo in human T lymphoblasts is catabolic, i.e., deamination to 2',3'-dideoxyinosine (2',3'-ddlno). At this point, the metabolic pathway diverges, to result in either cleavage and inactivation of 2',3'-ddlno by purine nucleoside phosphorylase or in 5'-phosphorylation by a phosphotransferase, a reaction that generates 2',3'-inosine monophosphate and ultimately the putative active metabolite 2',3'-dideoxy-ATP. Studies with kinase-deficient mutant CEM lines indicate, however, that 2'-F-dd-ara-A favors a more direct anabolic route toward formation of 2'-fluoro-dideoxynucleotides, catalyzed initially by 2'-deoxycytidine kinase. In MOLT-4 cells, amounts of 2'-fluoro-dideoxyarabinosyladenine di- and triphosphate formed were approximately 20-fold and 5-fold greater than the respective accumulation of 2',3'-dideoxy-ADP and 2',3'-dideoxy-ATP over the same time of exposure. This metabolic profile was supported by enzymological studies, which revealed that 2'-F-dd-ara-A is deaminated 10 times less rapidly than ddAdo and that the resulting deaminated product is resistant to hydrolysis by purine nucleoside phosphorylase. Under similar conditions, ddAdo was rapidly degraded through cleavage of its deamination product ddlno. Like ddAdo, 2'-F-dd-ara-A was found to be transported by passive diffusion and does not enter cells via the purine nucleoside transport carrier system. However, the rate of entry of 2'-F-dd-ara-A was about half that of ddAdo (9.7 pmol/10(6) cells/min for 2'-F-dd-ara-A versus 18.4 pmol/10(6) cells/min for ddAdo). This investigation, therefore, demonstrates that, under the conditions studied, 2'-F-dd-ara-A and its deamination product 2'-fluoro-2',3'-dideoxyarabinosylhypoxanthine have metabolic properties that differ significantly from those of their parent compounds ddAdo and ddlno. These properties, combined with the previously reported resistance of the fluorinated nucleosides to acid degradation, make these compounds interesting candidates for further study as orally administered agents for the inhibition of human immunodeficiency virus replication in patients with acquired immunodeficiency syndrome.
 ...
PMID:2'-Fluoro-2',3'-dideoxyarabinosyladenine: a metabolically stable analogue of the antiretroviral agent 2',3'-dideoxyadenosine. 210 83

Patients with congenital T lymphocyte deficiency disorders received transplants with parental bone marrow depleted of mature T cells by the use of an anti-T cell monoclonal antibody (CT-2) and complement. Our results with 16 consecutive patients (20 transplants) showed rapid engraftment of donor cells; cytoreduction (busulfan, cytosine arabinoside [ara-C], cyclophosphamide) was used in six transplants, and marrow ablation was used in six (ara-C, cyclophosphamide, 1,365-cGy total body irradiation). No patient received prophylactic anti-graft-v-host disease (GVHD) therapy posttransplant, and only one patient developed significant GVHD, which involved the skin, liver, and gastrointestinal tract. Seven others showed some manifestations of GVHD, but these were of minimal clinical significance and required only occasional steroid therapy. Overall, eight patients are alive and well; eight did not survive. Polyclonal immunoglobulin synthesis by donor memory B cells was seen shortly after transplantation, with peak donor-derived serum levels seen approximately 2 months after transplantation. After this initial immunoglobulin synthesis waned, another wave of B cell responses developed. This immunoglobulin response appears to be permanent. T cell functions appeared as soon as 3 weeks after transplantation. This experience in a variety of patients with combined immunodeficiency who received transplants with monoclonal antibody T cell-depleted marrow shows gratifying results with a consistent T and B cell benefit.
 ...
PMID:Immunologic reconstitution after haploidentical bone marrow transplantation for immune deficiency disorders: treatment of bone marrow cells with monoclonal antibody CT-2 and complement. 330 60

A new acyclic nucleoside phosphonate (13) containing an adenine moiety was synthesized, which acted as an excellent inhibitor of calf mucosal adenosine deaminase. This inhibitory property allows it to exert great synergistic effect on certain antiviral agents (e.g., ara-A, 37). Phosphonate 13 was not phosphorylated by the bovine brain guanylate kinase nor by 5-phosphoribosyl 1-pyrophosphate synthetase. Syntheses of biologically active nucleotide phosphonate 40 and its phosphonoamidate derivative 42 were accomplished, which showed remarkable activity against herpes viruses and exhibited low host cell toxicity. 3'-Azido-nucleoside phosphonate 20 and 3'-fluoronucleoside phosphonate 32, as well as the corresponding dinucleotide analogs 47 and 48, and their respective phosphonoamidates 53-56 were also synthesized as new compounds, among which phosphonoamidates 53-56 showed potent activity against human immunodeficiency virus. Phosphonoamidates 55 and 56 bearing a methyl D-alaninate moiety exhibited less cellular toxicity than 53 and 54 bearing a methyl L-alaninate moiety. Nucleotide phosphonate 40 as well as dinucleotide phosphonates 47 and 48 were found susceptible to degradation by phosphodiesterases. Their respective phosphonoamidates 42 and 53-56, however, were completely resistant to snake venom and spleen enzymes.
 ...
PMID:Design, synthesis, and structure-activity relationship of novel dinucleotide analogs as agents against herpes and human immunodeficiency viruses. 747 92

The glycosylation of 3,4-dicyano-2-[(ethoxymethylene)amino]pyrrole (7) with 2-deoxy-2-fluoro-alpha-D-erythro-pentofuranosyl bromide (2) furnished an anomeric mixture of nucleosides (8a,b). This mixture was separated, and the individual anomers were treated with methanolic ammonia to effect a concomitant deblocking and ring closure. This furnished both anomers of 2'-deoxy-2'-fluoro-ara-toyocamycin (9a,b). The cyano moiety of 9b was converted to the carboxamide moiety to furnish 2'-deoxy-2'-fluoro-ara-sangivamycin (10) and to the thiocarboxamide moiety to furnish 2'-deoxy-2'-fluoro-ara-thiosangivamycin (11). The target compounds 10 and 11 showed similar antiproliferative activity against L1210 cells in vitro, with IC50's of 3 and 5 microM. Antiviral evaluation revealed a somewhat different pattern of activity. All analogs, both alpha and beta anomers, were active against human cytomegalovirus (HCMV), albeit the beta anomers were most active. The beta anomers also were active against herpes simplex virus type 1 (HSV-1) and human immunodeficiency virus (HIV). Compound 10 was most active in the series, ca. 10-fold more potent than 11; IC50's for 10 ranged from 4 to 25 nM for HCMV, HIV, and varicella zoster virus (VZV) and from 30 to 500 nM for HSV-1. Even though compound 10 was cytotoxic, which will probably preclude its use as an antiviral drug (IC50's = 0.2-5.5 microM), the difference between cytotoxicity and activity against HCMV, HIV, and VZV was sufficient to indicate specific activity against a viral target.
 ...
PMID:Synthesis and antiproliferative and antiviral activity of 2'-deoxy-2'-fluoroarabinofuranosyl analogs of the nucleoside antibiotics toyocamycin and sangivamycin. 756 46

The mechanism of divergent anti-human immunodeficiency virus type 1 (HIV-1) activity of various 2',3'-dideoxynucleoside analogs (ddNs) in peripheral blood mononuclear cells (PBM) was studied. We demonstrate that the in vitro anti-HIV-1 activity of various ddNs varies profoundly and that the divergent antiviral activity is related to the extent of anabolic phosphorylation of each ddN and its counterpart 2'-deoxynucleoside (dN). We also show that certain ddNs cause a reduction of their counterpart dNTP formation in PBM in the following order: 2',3'-dideoxycytidine (ddC) >> 2',3'-didehydro-2',3'-dideoxythymidine (d4T), 3'-thia-2',3'-dideoxycytidine (3TC), 2',3'-dideoxyinosine (ddI), 2',3'-dideoxyguanosine (ddG) > 3'-azido-2',3'-dideoxythymidine (AZT) > 2'-beta-fluoro-2',3'-dideoxyadenosine (F-ara-ddA). Based on the phosphorylation profiles, anti-HIV-1 ddNs can be classified into two groups: (i) cell-activation-dependent ddNs such as AZT and d4T that are preferentially phosphorylated, yield higher ratios of ddNTP/dNTP, and exert more potent anti-HIV-1 activity in activated cells than in resting cells; and (ii) cell-activation-independent ddNs including ddI (and 2',3'-dideoxyadenosine), F-ara-ddA, ddG, ddC, and 3TC that produce higher ratios of ddNTP/dNTP and exert more potent anti-HIV-1 activity in resting cells. These data should provide a basis for the elucidation of the mechanism of the divergent antiretroviral activity of ddNs.
 ...
PMID:Divergent anti-human immunodeficiency virus activity and anabolic phosphorylation of 2',3'-dideoxynucleoside analogs in resting and activated human cells. 817 73

We determined the anti-human immunodeficiency virus type 1 (anti-HIV-1) activities of various dideoxy-nucleoside analogs by using phytohemagglutinin-activated peripheral blood mononuclear cells (PHA-PBMs) and resting PBMs (R-PBMs) as target cells. The comparative order of anti-HIV-1 activity in PHA-PBMs was azidothymidine (AZT) > dideoxycytidine (ddC) > dideoxythymidinene (d4T) > dideoxyinosine (ddI) and 9-(2-phosphonylmethoxyethyl)adenine (PMEA) > 2'-beta-fluoro-dideoxyadenosine (F-ara-ddA), while that in R-PBMs was ddC > ddI, PMEA, and F-ara-ddA, >> AZT and d4T. A pronucleotide, bis-(S-acetylthioethanol)phosphotriester-ddAMP, which bypasses the anabolic monophosphorylation step for the intracellular delivery of ddAMP, was highly active both in PHA-PBMs and R-PBMs. These data may have basic and clinical relevance in the design of anti-HIV chemotherapy, particularly combination chemotherapy with dideoxynucleosides, and in the development of active pronucleotides.
 ...
PMID:Comparative analysis of anti-human immunodeficiency virus type 1 activities of dideoxynucleoside analogs in resting and activated peripheral blood mononuclear cells. 858 44

We extended our previous study with 3'-azido-3'-deoxythymidine nucleotides [Proc. Natl. Acad. Sci. USA 91:5771-5775 (1994)] and examined the effects on human immunodeficiency virus type 1 (HIV-1) integrase of the nucleotides of three nucleoside analogues currently under evaluation in clinical trials: beta-D-2',3'-didehydro-3'-deoxythymidine, beta-D-2'-ara-fluoro-2', 3'-dideoxyadenosine, and beta-L-2',3'-dideoxy-3'-thiacytidine. Beta-D-2',3'-Didehydro-3'-deoxythymidine and beta-D-2'-ara-fluoro-2',3'-dideoxyadenosine nucleotides had IC50 values for strand transfer of 100 and 200 microM, respectively, whereas the corresponding 2',3'-dideoxynucleoside triphosphates, ddT triphosphate and ddA triphosphate, did not inhibit the integrase at 800 and 200 microM, respectively. Beta-L-2',3'-Dideoxy-3'-thiacytidine triphosphate had no effect up to 500 microM. The L-enantiomers of 5-fluoro-2',3'-dideoxycytidine monophosphate and triphosphate had IC50 values of approximately 40 microM, whereas their D-enantiomer isomers showed no inhibition at 200 microM. NAD, pyridoxal phosphate, and coumermycin A1, which exhibit no antiviral activity but are typically used to probe nucleotide binding sites, were also tested. NAD was inactive, and its etheno derivative exhibited activity at 1 mM. In contrast, pyridoxal phosphate (IC50 = 18 microM and coumermycin A1 (IC50 = 5 microM were potent inhibitors. None of the coumermycin monomeric derivatives were active integrase inhibitors. The physiological ribonucleotides ATP and GTP inhibited HIV-1 integrase at or near cellular concentrations, suggesting that they may regulate HIV-1 integrase activity in cells. In general, the active nucleotides tested inhibited binding of HIV-1 integrase to its substrate DNA an inhibited an integrase deletion mutant containing only amino acids 50-212, indicating that nucleotides bind to the enzyme catalytic core. Consisently, the choice of nucleophile in the 3'-processing reaction was blocked to the same extent regardless of the nucleotide used (water, glycerol, or the viral DNA hydroxyl) by the enzyme. These observations suggest new strategies for antiviral drug development that could be based on nucleotide analogues as inhibitors of HIV-1 integrase.
 ...
PMID:Effects of nucleotide analogues on human immunodeficiency virus type 1 integrase. 860 89

Thymidine (Thd), 1-beta-D-arabinosylthymine (ara-T) and 3'-fluoro-3'-deoxythymidine (FLT) have been substituted at N-3 by a methyl or a 2-fluoroethyl group. FLT and ara-T are markedly inhibitory against human immunodeficiency virus type 1 (HIV-1) and HIV-2, and herpes simplex virus type 1 (HSV-1) and HSV-2, respectively. Modification at N-3 of these compounds markedly decreases both the antiviral and cytostatic activity of the parent compounds FLT and ara-T except for N-3-(methyl)-Thd that proved highly cytostatic for murine leukaemia L1210 cells. The decreased biological activity of the N-3-substituted pyrimidine nucleoside analogues coincides with a significantly lower affinity of the modified Thd analogues for the cellular and viral (activating) nucleoside kinases.
 ...
PMID:The effect of a methyl or 2-fluoroethyl substituent at the N-3 position of thymidine, 3'-fluoro-3'-deoxythymidine and 1-beta-D-arabinosylthymine on their antiviral and cytostatic activity in cell culture. 1654 2

The cytostatic deoxycytidine analog cytarabine (ara-C) is the most active agent available against acute myelogenous leukemia (AML). Together with anthracyclines, ara-C forms the backbone of AML treatment for children and adults. In AML, both the cytotoxicity of ara-C in vitro and the clinical response to ara-C therapy are correlated with the ability of AML blasts to accumulate the active metabolite ara-C triphosphate (ara-CTP), which causes DNA damage through perturbation of DNA synthesis. Differences in expression levels of known transporters or metabolic enzymes relevant to ara-C only partially account for patient-specific differential ara-CTP accumulation in AML blasts and response to ara-C treatment. Here we demonstrate that the deoxynucleoside triphosphate (dNTP) triphosphohydrolase SAM domain and HD domain 1 (SAMHD1) promotes the detoxification of intracellular ara-CTP pools. Recombinant SAMHD1 exhibited ara-CTPase activity in vitro, and cells in which SAMHD1 expression was transiently reduced by treatment with the simian immunodeficiency virus (SIV) protein Vpx were dramatically more sensitive to ara-C-induced cytotoxicity. CRISPR-Cas9-mediated disruption of the gene encoding SAMHD1 sensitized cells to ara-C, and this sensitivity could be abrogated by ectopic expression of wild-type (WT), but not dNTPase-deficient, SAMHD1. Mouse models of AML lacking SAMHD1 were hypersensitive to ara-C, and treatment ex vivo with Vpx sensitized primary patient-derived AML blasts to ara-C. Finally, we identified SAMHD1 as a risk factor in cohorts of both pediatric and adult patients with de novo AML who received ara-C treatment. Thus, SAMHD1 expression levels dictate patient sensitivity to ara-C, providing proof-of-concept that the targeting of SAMHD1 by Vpx could be an attractive therapeutic strategy for potentiating ara-C efficacy in hematological malignancies.
 ...
PMID:Targeting SAMHD1 with the Vpx protein to improve cytarabine therapy for hematological malignancies. 2814 43


1 2 Next >>