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Deak J, McElfresh M, Clem JR, Hao Z, Konczykowski M, Muenchausen R, Foltyn S, Dye R. Irreversibility line in YBa2Cu3O7 thin films: Correlation of transport and magnetic behavior. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 49:6270-6279. [PMID: 10011613 DOI: 10.1103/physrevb.49.6270] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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102
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Hao Z, Hu CR. Flux motion in anisotropic type-II superconductors near Hc2. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 48:16818-16821. [PMID: 10008272 DOI: 10.1103/physrevb.48.16818] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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103
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Hao Z. Transverse magnetization, torque, and anisotropy in anisotropic type-II superconductors in the mixed state. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 48:16822-16825. [PMID: 10008273 DOI: 10.1103/physrevb.48.16822] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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104
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Clem JR, Hao Z. Theory for the hysteretic properties of the low-field dc magnetization in type-II superconductors. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 48:13774-13783. [PMID: 10007779 DOI: 10.1103/physrevb.48.13774] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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105
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Hao Z, Clem JR. Comment on "From isotropic to anisotropic superconductors: A scaling approach". PHYSICAL REVIEW LETTERS 1993; 71:301. [PMID: 10054916 DOI: 10.1103/physrevlett.71.301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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106
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Hao Z, Stowe EE, Ahluwalia G, Baker DC, Hebbler AK, Chisena C, Musser SM, Kelley JA, Perno CF, Johns DG. Characterization of 2',3'-dideoxycytidine diphosphocholine and 2',3'-dideoxycytidine diphosphoethanolamine. Prominent phosphodiester metabolites of the anti-HIV nucleoside 2',3'-dideoxycytidine. Drug Metab Dispos 1993; 21:738-44. [PMID: 7690699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
2',3'-Dideoxycytidine (ddCyd) is among the most potent of the anti-human immunodeficiency virus (HIV) agents of the dideoxynucleoside class. Its pharmacologically active metabolite 2',3'-dideoxycytidine 5'-triphosphate (ddCTP) is an effective inhibitor of HIV reverse transcriptase and thus of HIV replication. ddCyd differs, however, from other dideoxynucleoside agents such as 3'-azido-3'-deoxythymidine and 2',3'-dideoxyinosine in its capacity to generate phosphodiester metabolites (i.e. ddCDP choline and ddCDP ethanolamine). We have synthesized and characterized these two diesters, and established their identity with the metabolites formed in ddCyd-treated Molt-4 cells. Toward this end, the biologically generated metabolites have been isolated on a preparative scale and compared with the synthetic compounds mass spectroscopically, chromatographically, and enzymatically (i.e. their relative susceptibility to the catabolic enzymes alkaline phosphatase and venom phosphodiesterase). The concentration reached by each of these two phosphodiesters within cells can, under certain conditions, equal or exceed that of ddCTP, and their half-times of disappearance are long, indicating that they may serve as depot forms of ddCyd. The possible role of these phosphodiesters in contributing to the unusual toxicity of ddCyd is discussed.
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Deak J, McElfresh M, Clem JR, Hao Z, Konczykowski M, Muenchausen R, Foltyn S, Dye R. Identifying the loss of critical current density in YBa2Cu3O7 thin films. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 47:8377-8380. [PMID: 10004871 DOI: 10.1103/physrevb.47.8377] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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108
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Dodd HM, Horn N, Hao Z, Gasson MJ. A lactococcal expression system for engineered nisins. Appl Environ Microbiol 1992; 58:3683-93. [PMID: 1482189 PMCID: PMC183161 DOI: 10.1128/aem.58.11.3683-3693.1992] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The nisin-producing Lactococcus lactis strain FI5876 has been modified and developed for use as an expression system for engineered nisin variants. Insertional inactivation of the resident nisA gene had a polar effect on downstream genes, including those involved in nisin immunity. However, subsequent chromosomal rearrangements in this region involving a newly discovered insertion element (IS905) generated a strain that was deficient in the nisA gene product but expressed those nisin determinants necessary for prenisin maturation, secretion, and immunity. Complementation of the lesion in the nisA gene by plasmid-encoded nisA genes containing site-specific mutations resulted in the exclusive production of altered nisins containing specific amino acid substitutions.
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Cho JH, Hao Z, Johnston DC. Magnetization scaling of single-crystal Bi2Sr2CaCu2O8 below Tc. PHYSICAL REVIEW. B, CONDENSED MATTER 1992; 46:8679-8682. [PMID: 10002652 DOI: 10.1103/physrevb.46.8679] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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110
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Hao Z, Clem JR. Angular dependences of the thermodynamic and electromagnetic properties of the high-Tc superconductors in the mixed state. PHYSICAL REVIEW. B, CONDENSED MATTER 1992; 46:5853-5856. [PMID: 10004398 DOI: 10.1103/physrevb.46.5853] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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111
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Perno CF, Cooney DA, Gao WY, Hao Z, Johns DG, Foli A, Hartman NR, Caliò R, Broder S, Yarchoan R. Effects of bone marrow stimulatory cytokines on human immunodeficiency virus replication and the antiviral activity of dideoxynucleosides in cultures of monocyte/macrophages. Blood 1992; 80:995-1003. [PMID: 1379854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Cells of the monocyte lineage are important targets for the replication of human immunodeficiency virus (HIV). Our group and others have previously shown that granulocyte-macrophage colony-stimulating factor (GM-CSF) stimulates HIV replication in monocyte/macrophages, but that it also enhances the anti-HIV activity of 2',3'-dideoxy-3'-azidothymidine (AZT). In the present study, we have explored the effects of other bone marrow stimulatory cytokines on the replication of HIV and on the anti-HIV activity of certain dideoxynucleosides in human peripheral blood monocyte/macrophages (M/M). Like GM-CSF, macrophage CSF (M-CSF) enhanced HIV replication in M/M. In contrast, granulocyte CSF (G-CSF) and erythropoietin (Epo) had no such effects. The anti-HIV activity of zidovudine (AZT) was increased in M/M exposed to GM-CSF. In contrast, the anti-HIV activity of AZT was unchanged in M/M exposed to M-CSF, and the activities of 2',3'-dideoxycytidine (ddC) and 2',3'-dideoxyinosine (ddl) were unchanged or slightly diminished in M/M stimulated with GM-CSF or M-CSF. These differential activities of AZT and ddC were paralleled by differential effects of the cytokines on the anabolism of these drugs to their active 5'-triphosphate moieties. GM-CSF increased the levels of AZT-5'-triphosphate (at least in part through an increase in thymidine kinase activity) and overall induced an increase in the ratio of AZT-5'-triphosphate/thymidine-5'-triphosphate. In contrast, M-CSF-induced increases in AZT-5'-triphosphate were roughly matched by increases in thymidine-5'-triphosphate. Also, GM-CSF- or M-CSF-induced increases in the levels of ddC-5'-triphosphate were associated with parallel increases in the levels of deoxycytidine-5'-triphosphate (the physiologic nucleoside that competes at the level of reverse transcriptase), so that there was relatively little net change in the ddC-5'-triphosphate/deoxycytidine-5'-triphosphate ratio. Thus, bone marrow stimulatory cytokines may have a variety of effects on HIV replication and on the activity and metabolism of dideoxynucleosides in M/M.
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Hao Z, Hang B, Wang Y. [Hypoglycemic effect of fructus Ligustri Lucidi]. ZHONGGUO ZHONG YAO ZA ZHI = ZHONGGUO ZHONGYAO ZAZHI = CHINA JOURNAL OF CHINESE MATERIA MEDICA 1992; 17:429-31, 447. [PMID: 1445651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The decoction of Fructus Ligustri Lucidi (FLL) 15.30 g/kg ig for 10 days significantly decreased the blood glucose level in normal mice. FLL 30 g/kg before or after the treatment of alloxan also decreased the blood glucose level in alloxan diabetic mice. The elevation of blood glucose level induced by adrenaline or glucose was antagonized by FLL.
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113
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Hao Z, Clem JR. Limitations of the London model for the reversible magnetization of type-II superconductors. PHYSICAL REVIEW LETTERS 1991; 67:2371-2374. [PMID: 10044409 DOI: 10.1103/physrevlett.67.2371] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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114
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Coffey MW, Hao Z. Dipolar electric field induced by a vortex moving in an anisotropic superconductor. PHYSICAL REVIEW. B, CONDENSED MATTER 1991; 44:5230-5234. [PMID: 9998332 DOI: 10.1103/physrevb.44.5230] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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115
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Clem JR, Coffey MW, Hao Z. Lower critical field of a Josephson-coupled layer model of high-Tc superconductors. PHYSICAL REVIEW. B, CONDENSED MATTER 1991; 44:2732-2738. [PMID: 9999843 DOI: 10.1103/physrevb.44.2732] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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116
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Ford H, Cooney DA, Ahluwalia GS, Hao Z, Rommel ME, Hicks L, Dobyns KA, Tomaszewski JE, Johns DG. Cellular pharmacology of cyclopentenyl cytosine in Molt-4 lymphoblasts. Cancer Res 1991; 51:3733-40. [PMID: 1712247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The toxicity, uptake, and metabolism of the oncolytic nucleoside cyclopentenyl cytosine (CPEC) have been examined in the Molt-4 line of human lymphoblasts. This compound is known to be converted to its 5'-triphosphate, which inhibits CTP synthetase and depletes the pools of cytidine nucleotides. In the Molt-4 system, the concentration of drug reducing proliferation by 50% in a 24-h incubation was between 50 and 100 nM. Cytidine, uridine, and nitrobenzylthioinosine almost fully prevented the cytotoxicity of CPEC when introduced shortly before or together with the drug, but only cytidine was effective as an antidote when added 12 h after 200 nM CPEC. Studies of the cellular entry of CPEC revealed that nitrobenzylthioinosine fully blocked this process over a 60-s interval and for as long as 2 h, suggesting that the initial interiorization was mediated by facilitated diffusion. In Molt-4 cells incubated with tritiated CPEC, 9 metabolites could be distinguished: prominent among these was cyclopentenyl uridine (CPEU), the deamination product of CPEC; other major metabolites included the 5'-mono-, di-, and triphosphates of CPEC, and of CPEU, along with two phosphodiesters provisionally identified as CPEC-diphosphate choline and CPEC-diphosphate ethanolamine. When the accumulation of CPEC-5'-triphosphate was measured as a function of concentration of the drug in the medium, the process was found not to be saturable by levels of CPEC up to 1000 nM. In cells incubated with 200 nM drug, CPEC-5'-triphosphate accumulated rapidly and linearly for approximately 4 h, the time for doubling of the concentration being 2 h. After a 16-h incubation with 100 nM CPEC, the concentration of CPEC-5'-triphosphate was 50-fold that of the parent drug in the medium and could be readily monitored spectrophotometrically in high-pressure liquid chromatography effluents without recourse to radiolabeled nucleoside. In 2-h incubations, the concentration of free CPEC required to reduce CTP by 50% was 150 nM; this corresponded to a CPEC-5'-triphosphate level of 750 nM. After washout of extracellular CPEC, CPEC-5'-triphosphate decayed with a half-life that ranged from 9 to 14 h. Twenty-four h after washout of 200 nM CPEC (the concentration of drug reducing proliferation by 80%), cells had not resumed proliferation, and CTP pools were still depressed by 90%. Cytidine, uridine, and nitrobenzylthioinosine all strongly repressed the anabolic phosphorylation of CPEC when added to Molt-4 cells along with the drug.(ABSTRACT TRUNCATED AT 400 WORDS)
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Balzarini J, Holy A, Jindrich J, Dvorakova H, Hao Z, Snoeck R, Herdewijn P, Johns DG, De Clercq E. 9-[(2RS)-3-fluoro-2-phosphonylmethoxypropyl] derivatives of purines: a class of highly selective antiretroviral agents in vitro and in vivo. Proc Natl Acad Sci U S A 1991; 88:4961-5. [PMID: 1711214 PMCID: PMC51787 DOI: 10.1073/pnas.88.11.4961] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
A new class of compounds, 9-[(2RS)-3-fluoro-2-phosphonylmethoxypropyl] [(RS)-FPMP] derivatives of purines, is described that has selective activity against a broad spectrum of retroviruses [including human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2)] but not other RNA or DNA viruses. This activity spectrum is completely different from that of the parental compounds, 9-[(2S)-3-hydroxy-2-phosphonylmethoxypropyl] [(S)-HPMP] derivatives of purines, which are active against a broad range of DNA viruses. The racemic (RS)-FPMP derivatives of adenine and 2,6-diaminopurine, termed (RS)-FPMPA and (RS)-FPMPDAP, respectively, are markedly more selective as in vitro antiretroviral agents than their 9-(2-phosphonylmethoxyethyl) (PME) counterparts, PMEA and PMEDAP. Also, (RS)-FPMPA and (RS)-FPMPDAP have a substantially higher therapeutic index in mice in inhibiting Moloney murine sarcoma virus-induced tumor formation and associated death and are markedly less inhibitory to human bone marrow cells than PMEA and PMEDAP. The diphosphate derivative of (RS)-FPMPA [(RS)-FPMPApp] is a potent and selective inhibitor of HIV-1 reverse transcriptase but not of HSV-1 DNA polymerase or DNA polymerase alpha. (RS)-FPMPApp, akin to PMEA diphosphate (PMEApp), acts as a DNA chain terminator. The DNA chain-terminating properties of PMEApp and (RS)-FPMPApp seem to be a prerequisite for acyclic nucleoside phosphonates to exhibit antiretrovirus (i.e., anti-HIV) activity.
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118
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Balzarini J, holy A, Jindrich J, Dvorakova H, Hao Z, Snoeck R, Herdewijn P, Johns D, De Clercq E. Potent and selective anti-retrovirus activity of 9-(RS)-(3-fluoro-2-phosphonylmethoxypropyl) purine derivatives. Antiviral Res 1991. [DOI: 10.1016/0166-3542(91)90091-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Hao Z, Clem JR. Reversible magnetization and torques in anisotropic high- kappa type-II superconductors. PHYSICAL REVIEW. B, CONDENSED MATTER 1991; 43:7622-7630. [PMID: 9996380 DOI: 10.1103/physrevb.43.7622] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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120
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Balzarini J, Hao Z, Herdewijn P, Johns DG, De Clercq E. Intracellular metabolism and mechanism of anti-retrovirus action of 9-(2-phosphonylmethoxyethyl)adenine, a potent anti-human immunodeficiency virus compound. Proc Natl Acad Sci U S A 1991; 88:1499-503. [PMID: 1705039 PMCID: PMC51046 DOI: 10.1073/pnas.88.4.1499] [Citation(s) in RCA: 164] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
9-(2-Phosphonylmethoxyethyl)adenine (PMEA) is a potent and selective inhibitor of retrovirus (i.e., human immunodeficiency virus) replication in vitro and in vivo. Uptake of PMEA by human MT-4 cells and subsequent conversion to the mono- and diphosphorylated metabolites (PMEAp and PMEApp) are dose-dependent and occur proportionally with the initial extracellular PMEA concentrations. Adenylate kinase is unable to phosphorylate PMEA. However, 5-phosphoribosyl-1-pyrophosphate synthetase directly converts PMEA to PMEApp with a Km of 1.47 mM and a Vmax that is 150-fold lower than the Vmax for AMP. ATPase, 5'-phosphodiesterase, and nucleoside diphosphate kinase are able to dephosphorylate PMEApp to PMEAp, albeit to a much lower extent than the dephosphorylation of ATP. PMEApp has a relatively long intracellular half-life (16-18 hr) and has a much higher affinity for the human immunodeficiency virus-specified reverse transcriptase than for the cellular DNA polymerase alpha (Ki/Km: 0.01 and 0.60, respectively). PMEApp is at least as potent an inhibitor of human immunodeficiency virus reverse transcriptase as 2',3'-dideoxyadenosine 5'-triphosphate. Being an alternative substrate to dATP, PMEApp acts as a potent DNA chain terminator, and this may explain its anti-retrovirus activity.
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Hao Z, Clem JR, McElfresh MW, Civale L, Malozemoff AP, Holtzberg F. Model for the reversible magnetization of high- kappa type-II superconductors: Application to high-Tc superconductors. PHYSICAL REVIEW. B, CONDENSED MATTER 1991; 43:2844-2852. [PMID: 9997583 DOI: 10.1103/physrevb.43.2844] [Citation(s) in RCA: 118] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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122
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Masood R, Ahluwalia GS, Cooney DA, Fridland A, Marquez VE, Driscoll JS, Hao Z, Mitsuya H, Perno CF, Broder S. 2'-Fluoro-2',3'-dideoxyarabinosyladenine: a metabolically stable analogue of the antiretroviral agent 2',3'-dideoxyadenosine. Mol Pharmacol 1990; 37:590-6. [PMID: 2109183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
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.
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Hao Z, Cooney DA, Farquhar D, Perno CF, Zhang K, Masood R, Wilson Y, Hartman NR, Balzarini J, Johns DG. Potent DNA chain termination activity and selective inhibition of human immunodeficiency virus reverse transcriptase by 2',3'-dideoxyuridine-5'-triphosphate. Mol Pharmacol 1990; 37:157-63. [PMID: 1689452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
2',3'-Dideoxyuridine (ddUrd) exhibits poor if any anti-human immunodeficiency virus (HIV) activity in ATH8 and MT-4 cells. This is in agreement with the failure of ddUrd to be efficiently anabolized intracellularly to its 5'-triphosphate metabolite. However, 2',3'-dideoxyuridine-5'-triphosphate (ddUTP) proved to be a potent and selective inhibitor of the reverse transcriptase of HIV (Ki, 0.05 microM) and avian myeloblastosis virus (Ki, 1.0 microM). Bacterial DNA polymerase I, mammalian DNA polymerase alpha, terminal deoxyribonucleotidyl transferase, and Moloney murine leukemia virus reverse transcriptase were resistant to ddUTP. ddUTP is incorporated into the growing DNA chain principally at dTTP sites and inhibits further elongation. The potential of ddUTP as an anti-HIV therapeutic agent merits further investigation. However, to achieve this goal, it will be necessary to resort to techniques capable of delivering preformed phosphorylated ddUrd to the susceptible cells.
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Ahluwalia GS, Grem JL, Hao Z, Cooney DA. Metabolism and action of amino acid analog anti-cancer agents. Pharmacol Ther 1990; 46:243-71. [PMID: 2108451 DOI: 10.1016/0163-7258(90)90094-i] [Citation(s) in RCA: 179] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The preclinical pharmacology, antitumor activity and toxicity of seven of the more important amino acid analogs, with antineoplastic activity, is discussed in this review. Three of these compounds are antagonists of L-glutamine: acivicin, DON and azaserine; and two are analogs of L-aspartic acid: PALA and L-alanosine. All five of these antimetabolites interrupt cellular nucleotide synthesis and thereby halt the formation of DNA and/or RNA in the tumor cell. The remaining two compounds, buthionine sulfoximine and difluoromethylornithine, are inhibitors of glutathione and polyamine synthesis, respectively, with limited intrinsic antitumor activity; however, because of their powerful biochemical actions and their low systemic toxicities, they are being evaluated as chemotherapeutic adjuncts to or modulators of other more toxic antineoplastic agents.
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Freeman HS, Hao Z, Hsu WN. The Chromatographic Behavior of some Hydrophilic Dyes and Dye Intermediates on Thin Layers of Strong and Weak Ion Exchangers. ACTA ACUST UNITED AC 1989. [DOI: 10.1080/01483918908051770] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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126
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Perno CF, Yarchoan R, Cooney DA, Hartman NR, Webb DS, Hao Z, Mitsuya H, Johns DG, Broder S. Replication of human immunodeficiency virus in monocytes. Granulocyte/macrophage colony-stimulating factor (GM-CSF) potentiates viral production yet enhances the antiviral effect mediated by 3'-azido-2'3'-dideoxythymidine (AZT) and other dideoxynucleoside congeners of thymidine. J Exp Med 1989; 169:933-51. [PMID: 2538549 PMCID: PMC2189284 DOI: 10.1084/jem.169.3.933] [Citation(s) in RCA: 213] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
We have investigated the influence of granulocyte-macrophage CSF (GM-CSF) on the replication of HIV-1 in cells of monocyte/macrophage (M/M) lineage, and its effect on the anti-HIV activity of several 2'3'-dideoxynucleoside congeners of thymidine in these cells in vitro. We found that replication of both HTLV-IIIBa-L (a monocytotropic strain of HIV-1) and HTLV-IIIB (a lymphocytotropic strain) is markedly enhanced in M/M, but not in lymphocytes exposed to GM-CSF in culture. Moreover, GM-CSF reduced the dose of HIV required to obtain productive infection in M/M. Even in the face of this increased infection, GM-CSF also enhanced the net anti-HIV activity of 3'-azido-2'3'-dideoxythymidine (AZT) and several related congeners: 2'3'-dideoxythymidine (ddT), 2'3'-dideoxy-2'3'-didehydrothymidine (D4T), and 3'-azido-2'3'-dideoxyuridine (AZddU). Inhibition of viral replication in GM-CSF-exposed M/M was achieved with concentrations of AZT and related drugs, which were 10-100 times lower than those inhibitory for HIV-1 in monocytes in the absence of GM-CSF. Other dideoxynucleosides not related to AZT showed unchanged or decreased anti-HIV activity in GM-CSF-exposed M/M. To investigate the possible biochemical basis for these effects, we evaluated the metabolism of several drugs in M/M exposed to GM-CSF. We observed in these cells markedly increased levels of both parent and mono-, di-, and triphosphate anabolites of AZT and D4T compared with M/M not exposed to GM-CSF. By contrast, only limited increases of endogenous competing 2'-deoxynucleoside-5'-triphosphate pools were observed after GM-CSF exposure. Thus, the ratio of AZT-5'-triphosphate/2'-deoxythymidine-5'-triphosphate and 2'3'-dideoxy-2'3'-didehydrothymidine-5'-triphosphate/2'-deoxythymi dine- 5'-triphosphate is several-fold higher in GM-CSF-exposed M/M, and this may account for the enhanced activity of such drugs in these cells. Taken together, these findings suggest that GM-CSF increases HIV-1 replication in M/M, while at the same time enhancing the anti-HIV activity of AZT and related congeners in these cells. These results may have implications in exploring new therapeutic strategies in patients with severe HIV infection.
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Hao Z, Cooney DA, Hartman NR, Perno CF, Fridland A, DeVico AL, Sarngadharan MG, Broder S, Johns DG. Factors determining the activity of 2',3'-dideoxynucleosides in suppressing human immunodeficiency virus in vitro. Mol Pharmacol 1988; 34:431-5. [PMID: 2459590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Mitsuya and Broder [Proc. Natl. Acad. Sci. USA 83:1911-1915 (1986)] demonstrated that every purine (adenosine, guanosine, and inosine) and pyrimidine (cytidine and thymidine) nucleoside containing the 2',3'-dideoxyribose configuration, when evaluated against human immunodeficiency virus (HIV) in vitro, significantly suppressed both the infectivity and the cytopathic effect of the virus, with 2',3'-dideoxycytidine (ddCyd) being the most potent of the series (total antiviral protection at 0.5-1.0 microM). We have compared three factors likely to be of significance in determining the pharmacological activity of these compounds, i.e., (i) their abilities to influence pool sizes of physiological deoxynucleoside-5'-triphosphates, (ii) their capacity to generate the corresponding 2',3'-dideoxynucleoside-5'-triphosphates, and (iii) the effectiveness of these nucleoside-5'-triphosphates as inhibitors of HIV reverse transcriptase. In MOLT-4 cells (a human T cell line), ddCyd was the compound most efficiently converted to its 5'-triphosphate, whereas 2',3'-dideoxyguanosine and 2',3'-dideoxythymidine were the compounds least efficiently converted, generating levels of their corresponding 5'-triphosphates less than 0.1% of that seen with ddCyd when these nucleosides were compared on an equimolar basis (5 microM). The 3'-azido analogue of 2',3'-dideoxythymidine fell intermediate between these two extremes. As inhibitors of HIV reverse transcriptase, however, all the 5'-triphosphates, with the exception of 2',3'-dideoxyinosine-5'-triphosphate, fell within a narrow range of activity (Ki, 0.10-0.26 microM), affinities some 40-60 fold greater than those of the corresponding physiological 2'-deoxynucleoside-5'-triphosphates. Significant alterations in pool sizes of physiological 2'-deoxynucleoside-5'-triphosphates were not observed at pharmacologically effective drug levels. The relative ability of 2',3'-dideoxynucleosides to generate 5'-triphosphates intracellularly thus correlates much more closely than do the other two factors examined, in capacity to block HIV replication. These studies support the conclusion that, for purposes of design of new compounds of this general class, factors influencing efficiency of nucleotide formation and degradation (e.g., membrane transport mechanisms, affinities for nucleoside kinases and for nucleotide kinases and phosphatases) may be of equal or even greater importance than differences in the relative abilities of the resultant 2',3'-dideoxynucleoside-5'-triphosphates to inhibit the viral reverse transcriptase.
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Perno CF, Yarchoan R, Cooney DA, Hartman NR, Gartner S, Popovic M, Hao Z, Gerrard TL, Wilson YA, Johns DG. Inhibition of human immunodeficiency virus (HIV-1/HTLV-IIIBa-L) replication in fresh and cultured human peripheral blood monocytes/macrophages by azidothymidine and related 2',3'-dideoxynucleosides. J Exp Med 1988; 168:1111-25. [PMID: 2844951 PMCID: PMC2189024 DOI: 10.1084/jem.168.3.1111] [Citation(s) in RCA: 188] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Because of the probable role of HIV-infected monocyte/macrophages in the pathogenesis and progression of AIDS, it is essential that antiretroviral therapy address viral replication in cells of this lineage. Several dideoxynucleosides have been shown to have potent in vitro and, in the case of 3'-azido-2',3'-dideoxythymidine (AZT) and 2',3'-dideoxycytidine (ddC), in vivo activity against HIV. However, because these compounds must be phosphorylated (activated) in target cells, and because monocyte/macrophages may have levels of kinases that differ from those in lymphocytes, we investigated the capacity of these drugs to suppress HIV replication in monocyte/macrophages using HIV-1/HTLV-IIIBa-L (a monocytotropic isolate). In the present study, we observed that HTLV-IIIBa-L replication in fresh human peripheral blood monocyte/macrophages was suppressed by each of three dideoxynucleosides: 3'-azido-2',3'-dideoxythymidine (AZT), 2',3'-dideoxycytidine (ddC), and 2',3'-dideoxyadenosine (ddA). Similar results were observed in 5-d-cultured monocyte/macrophages, although higher concentrations of the drugs were required. We then studied the metabolism of AZT and ddC in such cells. The phosphorylation of ddC to a triphosphate moiety was somewhat decreased in monocyte/macrophages as compared with H9 T cells. On the other hand, the phosphorylation of AZT in monocyte/macrophages was markedly decreased to 25% or less of the level in T cells. However, when we examined the level of the normal endogenous 2'-deoxynucleoside triphosphate pools, which compete with 2',3'-dideoxynucleoside triphosphate for viral reverse transcriptase, we found that the level of 2'-deoxycytidine-triphosphate (dCTP) was six- to eightfold reduced, and that of 2'-deoxythymidine-triphosphate (dTTP) was only a small fraction of that found in T cell lines. These results suggest that the ratio of dideoxynucleoside triphosphate to normal deoxynucleoside triphosphate is a crucial factor in determining the antiviral activity of dideoxynucleosides in HIV target cells, and that the lower levels of dTTP may account for the antiretroviral activity of AZT in the face of inefficient phosphorylation of this compound.
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Freeman HS, Hao Z, McIntosh SA, Mills KP. Purification of Some Water Soluble Azo Dyes by High-Speed Countercurrent Chromatography. ACTA ACUST UNITED AC 1988. [DOI: 10.1080/01483919808068327] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Ahluwalia G, Cooney DA, Mitsuya H, Fridland A, Flora KP, Hao Z, Dalal M, Broder S, Johns DG. Initial studies on the cellular pharmacology of 2',3'-dideoxyinosine, an inhibitor of HIV infectivity. Biochem Pharmacol 1987; 36:3797-800. [PMID: 3120727 DOI: 10.1016/0006-2952(87)90440-0] [Citation(s) in RCA: 157] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Cooney DA, Ahluwalia G, Mitsuya H, Fridland A, Johnson M, Hao Z, Dalal M, Balzarini J, Broder S, Johns DG. Initial studies on the cellular pharmacology of 2',3'-dideoxyadenosine, an inhibitor of HTLV-III infectivity. Biochem Pharmacol 1987; 36:1765-8. [PMID: 3107569 DOI: 10.1016/0006-2952(87)90235-8] [Citation(s) in RCA: 105] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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