5-(2-iodovinyl)-2--deoxyuridine and brivudine

Murine mammary carcinoma FM3A cells, deficient in cytosol thymidine (dThd) kinase (TK) activity and transformed by the herpes simplex virus type 1 (HSV-1) or type 2 (HSV-2) TK gene (designated FM3A TK-/HSV-1 TK+ and FM3A TK-/HSV-2 TK+, respectively) proved extremely sensitive to the cytostatic action of the potent antiherpetic drugs (E)-5-(2-bromovinyl)-2'-deoxyuridine (BVDU) and (E)-5-(2-iodovinyl)-2'-deoxyuridine (IVDU). The fact that FM3A TK-/HSV-2 TK+ cells were 5-fold more sensitive to the cytostatic action of BVDU and IVDU but incorporated [125I]IVDU to a 20-fold lower extent into their DNA than did FM3A TK-/HSV-1 TK+ cells led us to conclude that incorporation of these compounds into DNA of HSV TK gene-transformed cell lines is not directly related to their cytostatic action. In attempts to unravel the mechanism of the cytostatic effects of BVDU and IVDU on HSV TK gene-transformed FM3A cells, both compounds were submitted to an intensive biochemical study. Thymidylate synthase was identified as the principal target enzyme for the cytostatic action of BVDU and IVDU since (i) both compounds were far more inhibitory to 2(1)-deoxyuridine (dUrd) than to dThd incorporation into HSV TK gene-transformed FM3A cell DNA, (ii) the cytostatic action of BVDU and IVDU was more readily reversed by dThd than by dUrd, (iii) both compounds strongly inhibited the metabolic pathway leading to the incorporation of 2'-deoxycytidine (dCyd) into DNA thymidylate, (iv) BVDU and IVDU strongly inhibited tritium release from [5-3H]dCyd and [5-3H]dUrd in intact HSV TK gene-transformed FM3A cells, and (v) [125I]IVDU accumulated intracellularly as its 5'-monophosphate to concentration levels considerably higher than those required to inhibit partially purified thymidylate synthase. The inhibitory effects mentioned under (i) to (iv) were not observed with the parental FM3A/0 and FM3A/TK- cells; they were more pronounced for FM3A TK-/HSV-2 TK+ cells than for FM3A TK-/HSV-1 TK+ cells, which correlates with the differential cytostatic effects of BVDU and IVDU on these cells.

Topics: Animals; Antiviral Agents; Bromodeoxyuridine; Cell Division; Cell Line, Transformed; DNA; Genes, Viral; Idoxuridine; Mice; Simplexvirus; Thymidine Kinase; Thymidylate Synthase

The incorporation of (E)-5-(2-iodovinyl)-2'-deoxyuridine (IVDU) into DNA of varicella-zoster virus (VZV)-infected human embryo fibroblasts was studied, using thymidine kinase-positive (TK+) and thymidine kinase-negative (TK-) VZV strains. [125I]IVDU was taken up by cells infected with TK+ VZV-, but not by TK- VZV- or mock-infected cells. [125I]IVDU was incorporated into both VZV DNA and cellular DNA of TK+ VZV-infected cells. When the cells were exposed to 0.3 microM IVDU, a more marked shift was noted in the buoyant density of viral DNA than of host DNA. In contrast, the DNAs isolated from TK- VZV- or mock-infected cells did not exhibit a detectable incorporation of [125I]IVDU. [125I] IVDU-labeled VZV DNA was purified from the viral nucleocapsids of TK+ VZV-infected cells. Substitution of no more than 0.1-1% of the thymidine residues in the VZV DNA by IVDU seemed to suffice to inhibit the replication of VZV.

Topics: Autoradiography; Biological Transport; Bromodeoxyuridine; Cells, Cultured; DNA, Viral; Dose-Response Relationship, Drug; Herpesvirus 3, Human; Humans; Idoxuridine; Nucleic Acid Hybridization; Thymidine; Thymidine Kinase; Time Factors; Virus Replication

The carbocyclic analogues of the potent and selective antiherpes agents (E)-5-(2-bromovinyl)-2'-deoxyuridine (BVDU), (E)-5-(2-iodovinyl)-2'-deoxyuridine (IVDU), and (E)-5-(2-bromovinyl)-2'-deoxycytidine (BVDC) were synthesized by conventional methods with use of carbocyclic 2'-deoxyuridine as starting material. C-BVDU, C-IVDU, and C-BVDC were equally selective, albeit slightly less potent, in their antiherpes action than BVDU, IVDU, and BVDC. Although resistant to degradation by pyrimidine nucleoside phosphorylases, C-BVDU did not prove more effective than BVDU in the systemic (oral, intraperitoneal) or topical treatment of HSV-1 infections in mice.

Topics: Animals; Antineoplastic Agents; Antiviral Agents; Bromodeoxyuridine; Cell Division; Cell Line; Cyclopentanes; Cytopathogenic Effect, Viral; Deoxycytidine; Deoxyuridine; Herpes Simplex; Humans; Mice; Mice, Hairless; Rabbits; Rats; Simplexvirus; Vaccinia virus; Vesicular stomatitis Indiana virus; Virus Cultivation

The carbocyclic analogues of (E)-5-(2-bromovinyl)-2'-deoxyuridine (C-BVDU) and (E)-5-(2-iodovinyl)-2'-deoxyuridine (C-IVDU), in which the sugar moiety is replaced by a cyclopentane ring, are as efficient substrates for the herpes simplex type 1 (HSV-1)-encoded thymidine kinase (TK) as their parent compounds (BVDU and IVDU). This conclusion is based on the binding affinities (Ki) of BVDU, IVDU, C-BVDU and C-IVDU to the HSV-1 TK and on the phosphorylation rates (Km, Vmax) of (125I)IVDU and (125I)C-IVDU by the enzyme. The specific phosphorylation of C-BVDU and C-IVDU by the viral TK may explain why these compounds are highly selective inhibitors of HSV-1 replication.

Topics: Animals; Antiviral Agents; Bromodeoxyuridine; Idoxuridine; Kidney; Kinetics; Phosphorylation; Rabbits; Simplexvirus; Thymidine Kinase

Murine mammary carcinoma (FM3A TK-/HSV-1 TK+) cells, which are thymidine kinase (TK)-deficient but have been transformed with the herpes simplex virus type 1 (HSV-1) TK gene are inhibited in their growth by (E)-5-(2-bromovinyl)-2'-deoxyuridine (BVDU), (E)-5-(2-iodovinyl)-2'-deoxyuridine (IVDU) and (E)-5-(2-bromovinyl)-2'-deoxycytidine (BVDC) at 0.5, 0.5 and 0.8 ng/ml, respectively; i.e., a concentration 5000 to 20 000-fold lower than that required to inhibit the growth of the corresponding wild-type FM3A/0 cells. Hence, transformation of tumor cells with the HSV-1 TK gene makes them particularly sensitive to the cytostatic action of BVDU and related compounds.

Topics: Animals; Antiviral Agents; Bromodeoxycytidine; Bromodeoxyuridine; Cell Division; Cell Line; Female; Genes, Viral; Idoxuridine; Mammary Neoplasms, Experimental; Mice; Mice, Inbred C3H; Phosphorylation; Simplexvirus; Thymidine Kinase; Transformation, Genetic

(E)-5-(2-Bromovinyl)-2'-deoxyuridine (BVDU) and various structurally related analogues thereof, i.e., (E)-5-(2-iodovinyl)-2'-deoxyuridine (IVDU) and (E)-5-(2-bromovinyl)-2'-deoxycytidine (BVDC), and the carbocyclic analogues of BVDU, IVDU, and BVDC, were evaluated for their inhibitory effects on the growth of murine mammary carcinoma FM3A cells, deficient in thymidine kinase (TK) activity but transformed with the herpes simplex virus type 1 (HSV-1) TK gene (designated FM3A/TK-/HSV-1 TK+). BVDU and its congeners were much more inhibitory to the growth of FM3A/TK-/HSV-1 TK+ than to the growth of the wild type (FM3A/0) cells. For BVDU, for example, the 50% inhibitory dose for the FM3A/TK-/HSV-1 TK+ cells was 0.5 ng/ml, as compared to 11 micrograms/ml for the FM3A/0 cells. Evidently, BVDU and its congeners required phosphorylation by the HSV-1 TK to exert their cytostatic action. In attempts to evaluate further the mechanism of this cytostatic action, BVDU, IVDU, and their carbocyclic analogues were evaluated for their inhibitory effects on thymidylate synthetase (TS) and their incorporation into DNA. TS was identified as one, but not the sole, target in the cytostatic activity of BVDU and its derivatives. With [125I]IVDU and its carbocyclic analogue C-[125I]IVDU, clear evidence was obtained for the incorporation of these radiolabeled analogues into DNA of the FM3A/TK-/HSV-1 TK+ cell line and a TS-deficient mutant thereof, FM3A/TK-/HSV-1 TK+/TS-. No incorporation was detected with [125I]IVDU or C-[125I]IVDU into DNA of FM3A/0 and FM3A/TS- cells. To what extent the incorporation of [125I]IVDU and C-[125I]IVDU contributed to their cytostatic action against FM3A/TK-/HSV-1 TK+ cells remains the subject of further study.

Topics: Animals; Antiviral Agents; Bromodeoxyuridine; Cell Division; Cell Transformation, Viral; DNA; Idoxuridine; Iodine Radioisotopes; Mammary Neoplasms, Experimental; Mice; Mice, Inbred C3H; Simplexvirus; Thymidine Kinase; Thymidylate Synthase; Tritium

The effect of (E)-5-(2-bromovinyl)-2'-deoxyuridine (BVDU) on replication of Epstein-Barr virus (EBV) was investigated and compared with Acyclovir (ACV). Both drugs inhibited EBV replication very rapidly. However, the inhibitory effect of ACV was readily reversed after removal of the drug, in contrast to the more prolonged effect exerted by BVDU, which persisted for more than 21 days. The 50% inhibitory doses of BVDU for virus replication (ED50) and lymphoblastoid cell growth (ID50) were 0.06 microM and 390 microM, respectively; the in vitro therapeutic index (ID50/ED50) was 6,500. Synthesis of EBV-induced polypeptides with molecular weights of 145K, 140K and 110K was partially reduced by BVDU. When superinfected Raji cells were exposed to 125I-labeled (E)-5-(2-iodovinyl)-2'-deoxyuridine (IVDU), larger amounts of (125I)IVDU were incorporated into viral DNA than cellular DNA.

Topics: Acyclovir; Antiviral Agents; Bromodeoxyuridine; Cell Line; DNA; DNA, Viral; Dose-Response Relationship, Drug; Herpesvirus 4, Human; Humans; Idoxuridine; Kinetics; Lymphocytes; Molecular Weight; Peptide Biosynthesis; Peptides; Viral Proteins; Virus Replication

Radiohalogenated (E)-5-(2-iodovinyl)-2'-deoxyuridine (IVDU, 4) and (E)-5-(2-bromovinyl)-2'-deoxyuridine (BVDU, 5) were synthesized by reaction of (E)-5-(2-carboxyvinyl)-2'-deoxyuridine (1) with radiolabelled iodide or bromide in the presence of chloramine-T. A "no-carrier-added" synthesis of [131I]IVDU was completed within 30 min providing a radiochemical yield of 65%. Alternatively, radioactive iodine was incorporated into IVDU using a halogen isotope exchange reaction catalyzed by cuprous ion. [82Br]BVDU was also prepared by direct neutron activation of unlabelled BVDU.

Topics: Antiviral Agents; Bromine; Bromodeoxyuridine; Encephalitis; Herpes Simplex; Humans; Idoxuridine; Iodine Radioisotopes; Isotope Labeling; Radioisotopes; Radionuclide Imaging

E-5-(2-Bromovinyl)-2'-deoxyuridine (BrvdUrd) and E-5-(2-iodovinyl)-2'-deoxyuridine (IvdUrd) are among the most potent and selective inhibitors of herpes simplex virus type 1 (HSV-1) replication. To elucidate the site of inhibition, we examined whether the halovinyl analogs are incorporated into DNA using two approaches. (i) In assays with purified DNA polymerases omitting dTTP from the reaction system, addition of either BrvdUTP or IvdUTP increased the polymerization reaction, indicating that these two analog triphosphates can be alternate substrates. (ii) When HSV-1-infected Vero cells were grown in the presence of either BrvdUrd or IvdUrd, there was an increase in the density of both the viral and cellular DNA. The viral DNA had 40% of its thymidine moiety substituted by IvdUrd when the concentration of [125I]IvdUrd was 24 microM (in the absence of added thymidine). At 30 microM BrvdUrd and 1 microM [2-14C]thymidine, the viral DNA had only 11% of its thymidine moiety substituted by BrvdUrd, presumably because of the presence of added thymidine. Following digestion of [125I]IvdUrd-substituted DNA with DNase 1, venom phosphodiesterase, and alkaline phosphatase, the radioactivity co-migrated with nonradioactive IvdUrd in thin layer chromatography. Under similar conditions, no detectable incorporation of either [125I]IvdUrd or BrvdUrd into mock-infected Vero cell DNA was observed. Thus, IvdUrd and BrvdUrd are incorporated into DNA of HSV-1 infected cells but not into DNA of uninfected cells.

Topics: Animals; Bromodeoxyuridine; Cell Line; Cell Transformation, Viral; Deoxyuridine; DNA Polymerase II; DNA Replication; DNA, Viral; Halogens; Idoxuridine; Kidney; Simplexvirus; Structure-Activity Relationship; Vinyl Compounds; Virus Replication

Topics: Animals; Antiviral Agents; Bromodeoxyuridine; Cytosol; Deoxyuridine; Herpesvirus 3, Human; Humans; Idoxuridine; In Vitro Techniques; Mitochondria; Phosphorylation; Rabbits; Simplexvirus; Substrate Specificity; Thymidine Kinase

Topics: Animals; Antiviral Agents; Bromodeoxyuridine; Cell Line; Deoxyuridine; Fluorodeoxyuridylate; Idoxuridine; Rabbits; Simplexvirus; Structure-Activity Relationship