Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.1.21 (thymidine kinase)
 7,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

By screening water and MeOH extracts of 30 Chinese medicinal plants for their anti-herpes simplex virus (HSV)-1 activity, a MeOH extract of the root tubers of Stephania cepharantha HAYATA showed the most potent activity on the plaque reduction assay with an IC50 value of 18.0 microg/ml. Of 49 alkaloids isolated from the MeOH extract, 17 alkaloids were found to be active against HSV-1, including 13 bisbenzylisoquinoline, 1 protoberberine, 2 morphinane and 1 proaporphine alkaloids, while benzylisoquinoline and hasubanane alkaloids were inactive. Although N-methylcrotsparine was active against HSV-1, as well as HSV-1 thymidine kinase deficient (acyclovir resistant type, HSV-1 TK-) and HSV-2 (IC50 values of 8.3, 7.7 and 6.7 microg/ml, respectively), it was cytotoxic. FK-3000 was found to be the most active against HSV-1, HSV-1 TK- and HSV-2 (IC50 values of 7.8, 9.9 and 8.7 microg/ml) with in vitro therapeutic indices of 90, 71 and 81, respectively. FK-3000 was found to be a promising candidate as an anti-HSV agent against HSV-1, acyclovir (ACV) resistant-type HSV-1 and HSV-2.
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PMID:Anti-herpes simplex virus activity of alkaloids isolated from Stephania cepharantha. 1022 Feb 83

This experiment tested the hypothesis that thyroid hormones are essential for a milk production response to growth hormone (GH) and prolactin (PRL). Prior to breeding, female transgenic mice expressing the herpes simplex type-I thymidine kinase in the thyroid were treated with ganciclovir to ablate thyroid follicular cells. To provide for normal gestation, thyrocyte-ablated mice were supplied thyroxine (T4) in drinking water (0.2 microgram/ml) until 7 days before parturition. Litter size was adjusted to 9 pups, hormone administration began on Day 2 of lactation, and mice were sacrificed on Day 12. There were 5-6 mice in each of 7 treatments that included nonablated controls, thyrocyte-ablated controls, and thyrocyte-ablated mice treated with T4, GH, PRL, GH + T4, and PRL + T4. Thyroxine was administered in drinking water, and GH and PRL (20 microgram/d) were administered by subcutaneous injection. Compared with thyrocyte-ablated controls, litter weight gain was unaffected when dams were treated with GH, PRL, or T4 alone. However, when dams were treated with GH or PRL in combination with T4, litter weight gain increased 13% compared with thyrocyte-ablated controls and 18% compared with GH or PRL-treated mice. Concentration of T4 in serum of pups averaged 62 ng/ml and did not differ among treatments. Concentration of T4 in serum of dams averaged 76 ng/ml when T4-treated. Thyroxine 5'-deiodinase (5'D), the enzyme that converts T4 to triiodothyronine, was quantitated in liver, kidney, and mammary gland. Quantity of 5'D was lower in liver and kidney of thyrocyte-ablated dams without T4 than in respective tissues of mice treated with T4, and there was no effect of GH or PRL. However, in mammary gland, 5'D was increased by treatment with GH, PRL, or T4. Data show that thyroid hormones are necessary for a galactopoietic response to GH and PRL and demonstrate a unique organ-specific regulation of 5'D by galactopoietic hormones.
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PMID:Prolactin and growth hormone stimulation of lactation in mice requires thyroid hormones. 1046 Jun 96

Ovarian cancer is the fourth most common cause of death in women. Gene therapy using the herpes simplex virus thymidine kinase (HSV-tk) gene followed by ganciclovir (GCV) treatment has been successfully applied in the treatment of different cancers in experimental animals and in humans. In a recent report, we have demonstrated that the HSV-tk/GCV system can be used efficiently to kill human epithelial ovarian cancer cells (Gynecol Obstet Invest 1997;43:268-75). In this work, we wanted to test the ability of the HSV-tk/GCV to treat ovarian cancer in an animal model.The immune-deficient nude mice model was employed, and mice were injected intraperitoneally with the human epithelial ovarian cancer cell line OVCAR3, 10(8) cell/mouse. The mice were divided into three different groups, groups 1 and 2 were treated by intraperitoneal injection of adenovirus carrying the HSV-tk gene (ad-tk) on day 3 after cell implantation. Group 1 received 2 x 10(8) pfu/mouse; group 2 received 20 x 10(8) pfu/mouse. Group 3 did not receive any viral injection and served as our negative control. All mice received GCV 10 mg/kg IP bid for 6 days. All mice were hosted in the same facilities and had access to food and water ad libitum. Mice in group 3 started to show clinical manifestations of disease by day 10, and all mice were dead by day 21 (16 +/- 1.5). At this point mice in groups 1 and 2 appeared perfectly healthy. Autopsy done on group 3 mice demonstrated multiple cancer implants in the abdominal cavity plus hemorrhagic ascitis. In contrast, autopsy on sample mice from groups 1 and 2 at the same time point failed to demonstrate any macroscopic or microscopic cancer.On further follow-up, mice in groups 1 and 2 started to show cancer-related signs, eg, weight loss, movement difficulty, poor reflex response, and finally death. Survival varied between 50 and 101 days with a mean of 66 +/- 17 days for group 1 and 74 +/- 13 days for group 2. Autopsy done on treated mice demonstrated multiple cancer implants and ascitis. In conclusion, a single injection of ad-tk/GCV was able to improve survival in an ovarian cancer mouse model from an average of 16 days to 74 days. Trials with multiple injection in a novel immune-competent mouse model of ovarian cancer are underway in our laboratory.
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PMID:Gene therapy of epithelial ovarian cancer using adenoviral vectors. 1083 93

The crystal structures of the full-length Herpes simplex virus type 1 thymidine kinase in its unligated form and in a complex with an adenine analogue have been determined at 1.9 A resolution. The unligated enzyme contains four water molecules in the thymidine pocket and reveals a small induced fit on substrate binding. The structure of the ligated enzyme shows for the first time a bound adenine analogue after numerous complexes with thymine and guanine analogues have been reported. The adenine analogue constitutes a new lead compound for enzyme-prodrug gene therapy. In addition, the structure of mutant Q125N modifying the binding site of the natural substrate thymidine in complex with this substrate has been established at 2.5 A resolution. It reveals that neither the binding mode of thymidine nor the polypeptide backbone conformation is altered, except that the two major hydrogen bonds to thymidine are replaced by a single water-mediated hydrogen bond, which improves the relative acceptance of the prodrugs aciclovir and ganciclovir compared with the natural substrate. Accordingly, the mutant structure represents a first step toward improving the virus-directed enzyme-prodrug gene therapy by enzyme engineering.
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PMID:Nucleoside binding site of herpes simplex type 1 thymidine kinase analyzed by X-ray crystallography. 1105 41

Sulfated polysaccharides exhibit many biological properties such as antiviral and anticoagulant activities. Herein, we report the antiviral activity of sulfated galactans extracted from the red sea-weed Bostrychia montagnei against herpes simplex virus types 1 (strain F and the thymidine kinase-deficient strains Field and B2006) and 2 (strain G). Two crude extracts obtained with cold and hot water as well as some fractions obtained by anion exchange chromatography, inhibited significantly the replication of the different strains of herpesviruses as determined by plaque reduction assays. The inhibitory effect of the compounds studied here took place only when they were added during the adsorption period. They were found to be highly selective antiviral substances, causing no impairment of Vero cell viability. Furthermore, they had no direct inactivating effect on virions by incubation in a virucidal assay. The antiviral activity could be correlated with the molecular weight and sulfate content of the polysaccharides. Although sulfated polysaccharides are generally endowed with anticoagulant properties, the results of the activated partial thromboplastin time and the thrombine time assays indicated that the natural sulfated polysaccharides from Bostrychia montagnei have very low anticoagulant activity, confirming that there is no relation between the antiviral and anticoagulant properties.
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PMID:Inhibitory effect of sulfated galactans from the marine alga Bostrychia montagnei on herpes simplex virus replication in vitro. 1129 40

6-Chloropurine derivatives of gamma-(Z)-ethylidene-2,3-dimethoxybutenolide 3a, gamma-(Z)-ethylidene-2-methoxy-3-(4-nitro)benzyloxybutenolide 3b, gamma-(Z)-ethylidene-2-(4-nitro)benzyloxy-3-methoxybutenolide 3c, gamma-(Z)-ethylidene-2,3-di(4-nitro)benzyloxybutenolide 3d, and dimethylphosphono-gamma-(Z)-ethylidene-2,3-dimethoxybutenolide 11 as well as the adenine derivative of gamma-(Z)-ethylidene-2,3-dimethoxybutenolide 6 were synthesized. The key steps in the high-yield synthesis of 6 involved hydration/dehydration of the C(4)=C(5) in the precursor 3a. In the presence of NH4OH at elevated temperature, 3a underwent a reverse Michael-type addition with water to produce hydrate 5. At 37 degrees C, 6 was also hydrated in the presence of S-adenosyl-L-homocysteine hydrolase to afford 5. Butenolide 6 exhibited an inhibitory property toward the enzyme. Such type II (enzyme-mediated addition of water across C(4)=C(5)) mechanism is the first example of "enzyme-substrate intermediate" inactivation of S-adenosyl-L-homocysteine hydrolase. In contrast with type I mechanism-based inactivation, reduction of enzyme-bound NADP(+) to NADPH was not observed. Upon treatment with HCl, stereoselective dehydration of 5 occurred to give the target molecule 6. At ambident temperature, 3a was hydrated in the presence of NH4OH or pig liver esterase to produce 6-chloropurine derivative 4. An unambiguous proof of the structures of 3-5 was obtained by X-ray crystallographic analysis. For the synthesis of phosphonate derivative 11, the key step involved chlorination of phosphonate 9 by use of CF3SO2Cl and 1,8-diazabicyclo[5.4.0]undec-7-ene in CH2Cl2. 6-Chloropurine-containing butenolide 3d, 6-chloropurine derivative of 4-hydroxybutenolide 4, and adenine-containing 4-hydroxybutenolide 5 did not show anticancer and antiviral activities. 6-Chloropurine-containing ethylidene-2,3-dialkoxybutenolides 3a-c and phosphonate 11, however, exhibited inhibitory activity against murine leukemias (L1210 and P388), breast carcinoma (MCF7), and human T-lymphoblasts (Molt4/C8 and CEM/0) cell lines. They were also notably active toward thymidine kinase-deficient varicella-zoster virus (TK(-)VZV). Adenine-containing ethylidene-2,3-dimethoxybutenolide 6 exhibited marked selectivity in cytostatic activity against the murine leukemia (P388) cell line.
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PMID:Synthesis and biological evaluation of purine-containing butenolides. 1135 10

OBJECTIVES: In vitro activities of thymidine kinase (TK, EC 2.7.1.21), adenosine kinase (AK, EC 2.7.1.20) and deoxycytidine kinase (dCK, EC 2.7.1.74) enzymes involved in the salvage pathway of DNA precursor synthesis, in homogenates of the rat liver and kidney, were examined. Type I iodothyronine-5'-deiodinase (5'D-I) is the main enzyme responsible for peripheral metabolism of thyroid hormones. This occurs especially in the liver, kidney and muscle. The activity of 5'D-I is inhibited bypropylthiouracil (PTU), an antithyroid drug. METHODS: The liver and kidney were collected from rats pretreated in vivo with either a 0.1% solution of PTU in drinking water for 2 weeks or injected with levothyroxine (L-T(4), 50 &mgr;g/kg BW, daily) for 2 weeks. The enzyme activities were measured by ascending chromatography and expressed asthe amounts of radioactive reaction products of the phosphorylation of dThd (for TK), ofdAdo (for AK and dCK) and of dGuo (for dCK). RESULTS: In liver homogenates, PTU-pretreatment decreased the activities of the three enzymes when compared to control values and those of L-T(4)-treated animals; also L-T(4) injections decreased the AK and dCK activities in the liver homogenates. PTU-pretreatment increased TK activity and the rate of dGuo phosphorylation in kidney homogenates, when compared to controls and to the L-T(4)-pretreated animals. Conversely, both PTU- and L-T(4)-pretreatment reduced the rate of dAdo phosphorylation in kidney homogenates. CONCLUSION: Changes in the activities of examined enzymes which participate inpyrimidine orpurine metabolism of the salvage pathway of DNA synthesis in the liver afterPTU-pretreatment (as shown herein) are similar to the changes of the 5'D-I activity after PTU-treatment (as reported by others). Thus, the observations suggest a role of the salvage pathway of DNA synthesis in the peripheral metabolism of thyroid hormones.
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PMID:Pyrimidine and purine salvage deoxyribonucleoside metabolism in hepatic and renal homogenates from rats pretreated with propylthiouracil or L-thyroxine. 1145 32

9-[(3-[18F]Fluoro-1-hydroxy-2-propoxy)methyl]guanine ([18F]FHPG, 2) has been synthesized by nucleophilic substitution of N(2)-(p-anisyldiphenylmethyl)-9-[[1-(p-anisyldiphenylmethoxy)-3-toluenesulfonyloxy-2-propoxy]methyl]guanine (1) with potassium [18F]fluoride/Kryptofix 2.2.2 followed by deprotection with 1 N HCl and purification with different methods in variable yields. When both the nucleophilic substitution and deprotection were carried out at 90 degrees C and the product was purified by HPLC (method A), the yield of compound 2 was 5-10% and the synthesis time was 90 min from EOB. However, if both the nucleophilic substitution and deprotection were carried out at 120 degrees C and the product was purified by HPLC, the yield of compound 2 decreased to 2%. When compound 2 was synthesized at 90 degrees C and purified by Silica Sep-Pak (method B), the yield increased to 10-15% and the synthesis time was 60 min from EOB. Similarly, 9-(4-[18F]fluoro-3-hydroxymethylbutyl)guanine ([18F]FHBG, 4) was synthesized with method A and method B in 9% and 10-15% yield, respectively, in a synthesis time of 90 and 60 min, respectively, from EOB. Compound 2 was relatively unstable in acidic medium at 120 degrees C while compound 4 was stable under the same condition. Both compound 2 and compound 4 had low lipid/water partition coefficient (0.126 +/- 0.022, n=5 and 0.165 +/- 0.023, n=5, respectively). Although it contains non-radioactive ganciclovir ( approximately 5-30 microg) as a chemical by-product, compound 2 synthesized by method B has a similar uptake in 9L glioma cells as that synthesized by method A, and is a potential tracer for imaging herpes simplex virus thymidine kinase gene expression in tumors using PET. Similarly, compound 4 synthesized by method B contains approximately 10-25 microg of penciclovir as a chemical by-product. Thus, the simplified one pot synthesis (method B) is a useful method for synthesizing both compound 2 and compound 4 in good yield for routine clinical use, and the method is readily amenable for automation.
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PMID:A simplified one-pot synthesis of 9-[(3-[18F]fluoro-1-hydroxy-2-propoxy)methyl]guanine([18F]FHPG) and 9-(4-[18F]fluoro-3-hydroxymethylbutyl)guanine ([18F]FHBG) for gene therapy. 1157 10

A new class of 5-(1-cyanamido-2-haloethyl)-2'-deoxyuridines (4-6) and arabinouridines (7, 8) were synthesized by the regiospecific addition of halogenocyanamides (X-NHCN) to the 5-vinyl substituent of the respective 5-vinyl-2'-deoxyuridine (2) and 2'-arabinouridine (3). Reaction of 2 with sodium azide, ceric ammonium nitrate, and acetonitrile-methanol or water afforded the 5-(1-hydroxy-2-azidoethyl)-(10) and 5-(1-methoxy-2-azidoethyl)-2'-deoxyuridines (11). In vitro antiviral activities against HSV-1-TK(+) (KOS and E-377), HSV-1-TK(-), HSV-2, VZV, HCMV, and DHBV were determined. Of the newly synthesized compounds, 5-(1-cyanamido-2-iodoethyl)-2'-deoxyuridine (6) exhibited the most potent anti-HSV-1 activity, which was equipotent to acyclovir and superior to 5-ethyl-2'-deoxyuridine (EDU). In addition, it was significantly inhibitory for thymidine kinase deficient strain of HSV-1 (EC(50) = 2.3-15.3 microM). The 5-(1-cyanamido-2-haloethyl)-2'-deoxyuridines (4-6) all were approximately equipotent against HSV-2 and were approximately 1.5- and 15-fold less inhibitory for HSV-2 than EDU and acyclovir, respectively. Compounds 4-6 were all inactive against HCMV but exhibited appreciable antiviral activity against VZV. Their anti-VZV activity was similar or higher to that of EDU and approximately 5-12-fold lower than that of acyclovir. The 5-(1-cyanamido-2-haloethyl)-(7,8) analogues of arabinouridine were moderately inhibitory for VZV and HSV-1 (strain KOS), whereas compounds 10 and 11 were inactive against herpes viruses. Compounds 5 and 6 also demonstrated modest anti-hepatitis B virus activity against DHBV (EC(50) = 19.9-23.6 microM). Interestingly, the related 5-(1-azido-2-bromoethyl)-2'-deoxyuridine (1n) analogue proved to be markedly inhibitory to DHBV replication (EC(50) = 2.6-6.6 microM). All compounds investigated exhibited low host cell toxicity to several stationary and proliferating host cell lines as well as mitogen-stimulated proliferating human T lymphocytes.
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PMID:Synthesis and antiviral activity of novel 5-(1-cyanamido-2-haloethyl) and 5-(1-hydroxy(or methoxy)-2-azidoethyl) analogues of uracil nucleosides. 1158 57

Controlled release of a water-soluble low-molecular-weight drug from silicone and its usefulness as a local therapeutic drug were studied. For application to ganciclovir/helpes simplex virus thymidine kinase (GCV/HSV-tk) suicide gene therapy for brain tumor, two kinds of GCV-containing silicone formulations were prepared for evaluation. In vitro, GCV release from matrix-type formulation consisting of a single matrix was characterized by Fickian diffusion, while covered-rod-type formulation, in which the side surface of the outer layer was covered with 100% silicone, exhibited a near-zero-order release pattern. In an in vivo study using a rat 9L glioblastoma model, administration of GCV-silicone formulation into brain tumor yielded sustained intracerebral GCV concentration for 4 days after administration, with excellent antitumor effect equal to or better than that of daily intraperitoneal administration of aqueous solution of GCV, at a dose less than 1/100 of the total dose of solution for intraperitoneal administration. Furthermore, GCV was undetectable in blood, suggesting that decrease in systemic adverse reactions can be expected with intracerebral administration of GCV-silicone formulation.
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PMID:New drug delivery system for water-soluble drugs using silicone and its usefulness for local treatment: application of GCV-silicone to GCV/HSV-tk gene therapy for brain tumor. 1239 64


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