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Biomedical subjects

W H Prusoff

Publications and source records attributed to W H Prusoff.

At least 37 records · Page 2Linked to original sources
PubMed1988

Effect of thymidine on uptake, DNA alkylation, and DNA repair in L1210 cells treated with 1,3-bis(2-chloroethyl)-1-nitrosourea or 3'-[3-(2-chloroethyl)-3-nitrosoureido]-3'-deoxythymidine.

In order to define the mechanism for the enhancement by thymidine (dThd) of the antitumor activity of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) and 3'-[3-(2-chloroethyl)-3-nitrosoureido]-3'-deoxythymidine (3'-CTNU) in mice, we have investigated the effect(s) of dThd on the uptake of nitrosourea by L1210 cells in culture, DNA alkylation, and repair of the alkyl lesion. Using a rapid centrifugation technique through silicone:paraffin oil, we observe a 1.3- and 1.5-fold increase in the uptake of radioactivity from 0.1 mM [chloroethyl-14C]BCNU in the presence of a 5- and 25-fold excess of dThd, respectively. Similarly, an enhancement of DNA alkylation was observed upon treatment of L1210 cells for up to 3 h with 0.1 mM [chloroethyl-14C]BCNU from 70 pmol 14C/mg DNA in control to 85, 95, and 120 pmol 14C/mg DNA with equimolar 5- and 25-fold excess dThd, respectively. No effect of dThd on the uptake of 0.1 mM [chloroethyl-14C]-3'-CTNU was observed, although a small increase in DNA alkylation at 3 h was evident. DNA repair, as measured by the amount of radioactivity remaining associated with the DNA after an initial 2-h treatment with labeled BCNU was largely unaffected by dThd. Although dThd appears to enhance the cellular uptake of BCNU and the alkylation of DNA by both BCNU and 3'-CTNU, dealkylative repair proceeds unhindered in the presence of dThd.

Alkylation↗
PubMed1988

Unusual structural features of 2',3'-dideoxycytidine, an inhibitor of the HIV (AIDS) virus.

The structure and conformation of 2',3'-dideoxycytidine, a potent inhibitor of the human immunodeficiency virus, was determined by X-ray crystallography. The nucleoside crystallizes in the tetragonal space group P4(1)2(1)2 with cell dimensions a = b = 8.698(4) and c = 26.155(9) A. Atomic parameters were refined by full-matrix least squares to a final value of R = 0.037 for 1926 observed reflections. The conformation of the furanose ring corresponds to the unusual C3'exo/C4'endo (3T4) pucker, similar to that found in one of the molecules of 3'-azidothymidine (AZT). The glycosidic torsion angle is also smaller than expected. The relevance of these unusual structural features to anti-AIDS activity is assessed.

Acquired Immunodeficiency Syndrome↗
PubMed1988

The effect of 5'-amino-5'-deoxythymidine on the pattern of polyadenylation of herpes simplex virus type 1 ribonucleic acid.

Treatment of herpes simplex virus type 1 (HSV-1) infected Vero cells with 5'-amino-5'-deoxythymidine (AdThd) causes a 65% reduction in the amount of total viral RNA present at late times of infection. This decrease is apparent as early as 6 hours post infection, affecting the levels of viral cytoplasmic polyadenylated (poly(A+] species to a greater extent than non-polyadenylated (poly(A-] RNA. Cytoplasmic viral poly(A+) RNA is present in AdThd-treated cultures at only 10% control poly(A+) levels, yet there is no evidence of a direct inhibition of RNA polyadenylation. Underrepresentation of RNA species in the cytoplasm is not sequence-specific. The results suggest that the antiviral activity of AdThd may involve not only incorporation into viral DNA, with a resultant decrease in viral transcription, but also perturbation of the relative amounts of viral poly(A+) RNA and poly(A-) RNA.

Animals↗
PubMed1988

Synthesis and antiviral activity of various 3'-azido analogues of pyrimidine deoxyribonucleosides against human immunodeficiency virus (HIV-1, HTLV-III/LAV).

Various 3'-azido analogues of pyrimidine deoxyribonucleosides have been synthesized and tested against human immunodeficiency virus (HIV-1, HTLV-III/LAV) in human peripheral blood mononuclear cells. Among these compounds, the 3'-azido analogues of thymidine (2), 3-(3-oxo-1-propenyl)thymidine (21), 2'-deoxyuridine (1), 2'-deoxy-5-bromouridine(5), 2'-deoxy-5-fluorocytidine (19), 2'-deoxy-5-iodouridine (6), 2'-deoxycytidine (18), 2'-deoxy-5-fluorouridine (4), 2'-deoxy-5-thiocyoanatouridine (16), 2'-deoxy-5-methylcytidine (20), 2'-deoxy-5-aminouridine (7), and 2'-deoxy-5-hydroxyuridine (10) were found to have significant antiviral activity, with EC50 values of 0.002, 0.01, 0.2, 1.0, 1.0, 1.1, 1.2, 4.8, 5.1, 5.1, 6.2, and 10 microM, respectively. The structure-activity relationships are discussed.

Antiviral Agents↗
PubMed1988

Synthesis and antiviral evaluation of carbocyclic analogues of 2'-azido- and 2'-amino-2'-deoxycytidine.

Carbocyclic analogues of 2'-azido- and 2'-amino-2'-deoxycytidine, compounds 8 and 9, were synthesized by an eight-step synthesis from (+/-)-(1 alpha,2 alpha,3 beta,5 beta)-3-amino-5-(hydroxymethyl)-1,2- cyclopentanediol (1), which was prepared from cyclopentadiene via an eight-step route. These compounds were tested in vitro against herpes simplex virus type 1 (HSV-1). The 2'-amino analogue was found to show moderate antiviral activity, with an ED50 of 50 microM. However, the 2'-azido analogue was not active at a concentration up to 400 microM.

Antiviral Agents↗
PubMed1987

Effect of incorporation of 5-iodo-2'-deoxyuridine into HSV-1 DNA on virion sensitivity to ultraviolet light.

First generation progeny herpes simplex type 1 (HSV-1) virions grown in the presence of 5-iodo-2'-deoxyuridine (IdUrd) were irradiated with either 254 or 302 nm ultraviolet (u.v.) light. The kinetics of virus inactivation revealed decreased sensitivity of IdUrd-substituted virions to irradiation with 302 nm light under all conditions examined, and with 254 nm u.v. light when substituted and control virions were irradiated at equal particle concentrations. Comparison of virus survival after irradiation measured in Vero or Xeroderma Pigmentosum (complementation group A) cells indicated that cellular repair of ultraviolet-induced lesions was not a significant factor in the observed decrease in u.v. sensitivity. IdUrd substitution altered neither the formation of ultraviolet-induced thymidine photoproducts nor the ability of irradiated virions to express delayed early viral enzymes (thymidine kinase, DNA polymerase). It is suggested that nucleocapsid proteins or the highly ordered structure of IdUrd-substituted virions play a key role in u.v. desensitization, either by the formation of non-lethal photoproducts or by the prevention of the formation of DNA-uracilyl free radicals.

DNA Repair↗
PubMed1987

Enhancement of the anticancer activity of bis(2-chloroethyl)nitrosourea in mice by coadministration of 2'-deoxyuridine, 2'-deoxycytidine, or thymidine.

The previous observation that the coadministration of a single dose of thymidine with the 3'-chloroethylnitrosourea analog of thymidine (3'-[3-(2-chloroethyl-3-nitrosoureido]-3'-deoxythymidine, 3'-CTNU) to mice bearing the L1210 or P388 leukemia enhanced the antitumor activity of 3'-CTNU, has led to a similar study of the potential effect on antitumor activity where thymidine, 2'-deoxyuridine, or 2'-deoxycytidine is coadministered with 1,3-bis(2-chloroethyl)-1-nitrosourea. Three levels of 1,3-bis(2-chloroethyl)-1-nitrosourea (10, 15, and 20 mg/kg) were coadministered to mice bearing the L1210 leukemia or the B16/F10 melanoma with each of the deoxyribonucleosides (2 g/kg). There was not only an increase in average days of survival of those that perished, but also a marked increase in the number of greater than 60-day survivors. The present report is a result of a determination of whether the augmented anticancer activity produced by a single injection of thymidine with 3'-CTNU was restricted to nitrosourea analogs of thymidine. The present study reveals not only that the phenomena of enhanced anticancer activity by the coadministration of thymidine can be extended to non-thymidine-containing nitrosoureas, but also that the coadministration of thymidine with 1,3-bis(2-chloroethyl)-1-nitrosourea produced an even more marked enhancement of antitumor activity than that previously observed when thymidine was coadministered with 3'-CTNU.

Animals↗
PubMed1987

Synthesis and antiviral activity of various 3'-azido, 3'-amino, 2',3'-unsaturated, and 2',3'-dideoxy analogues of pyrimidine deoxyribonucleosides against retroviruses.

Various 3'-azido, 3'-amino, 2',3'-unsaturated, 2',3'-dideoxy, and 5-substituted analogues of pyrimidine deoxyribonucleosides have been prepared and tested against Moloney-murine leukemia virus (M-MULV), a mammalian T-lymphotropic retrovirus in vitro. Among these compounds, the 3'-azido analogues of thymidine, 2'-deoxy-5-bromouridine, and 2'-deoxy-5-iodouridine, the 2',3'-unsaturated analogue of thymidine and and 2'-deoxycytidine, and 2',3'-dideoxycytidine were found to be most active, with ED50 values of 0.02, 1.5, 3.0, 2.5, 3.7, and 4.0 microM, respectively. These active compounds were nontoxic to the host SC-1 cells up to 100 microM concentration. The 3'-azido analogues of thymidine and 2'-deoxy-5-bromouridine were also tested in vitro against HTLV-III/LAV/AAV ("AIDS" virus) and found to be significantly active, with ED50 values of 0.23 and 2.3 microM, respectively. The structure-activity relationships are discussed.

Antiviral Agents↗
PubMed1986

Measurement of carbamoylating activity of nitrosoureas and isocyanates by a novel high-pressure liquid chromatography assay.

A new assay for carbamoylating activity using reversed phase liquid chromatography (HPLC) is described which offers several advantages over existing assays. A comparison was made of the extent of carbamoylation of the amino group of 5'-amino-5'-deoxythymidine (5'-AdThd) by chloroethyl isocyanate and a series of six nitrosoureas upon incubation (37 degrees) at pH 7.4 in phosphate-buffered saline. Determinations can be made in less than 30 min, whereas more than 24 hr are required in the paper chromatography method of Wheeler et al. [Cancer Res. 34, 194 (1974)]. There is a very high coefficient of correlation (r = 0.986, N = 7, P less than 0.001) between these two methods of analysis which allows compounds assayed by the new procedure to be compared to the data compiled through the earlier assay. The application of the new assay to the analysis of the rate of carbamoylating activity for these agents is presented, and a mechanistic basis for the marked differences among these structurally similar compounds is discussed.

Chromatography, High Pressure Liquid↗
PubMed1986

Potential targets for antiviral chemotherapy.

Serendipity and random screening have been successful in producing effective antiviral agents. The increase in our knowledge of the basic biochemistry of viral replication and of virus-host interrelationships has revealed not only an understanding of the targets upon which existing antiviral agents exert their inhibitory effect, but also has uncovered new potential targets. The hope is that such molecular understanding will afford the synthesis of compounds with selective antiviral activity. A review of various viral targets which are potentially susceptible to attack, and a few approaches for development of antiviral agents are presented.

Antiviral Agents↗
PubMed1986

Production of herpes simplex virus type 1 thymidine kinase in the presence of thymidine analogues.

Treatment of herpes simplex virus type 1 (HSV-1) infected Vero, BHK, BHKtk- and LMtk- cells with 5-iodo-5'-amino-2',5'-dideoxyuridine (AIdUrd) caused increased synthesis of ICP36 and an increase in HSV-1 thymidine kinase (tk) activity at late times of infection. The overproduced ICP36 was identified as the HSV-1 encoded tk protein by immunoprecipitation. Whereas the thymidine analogue 5'-amino-5'-deoxythymidine (AdThd) caused an increase in HSV-1 tk synthesis and activity in wild type Vero and BHK cells, 5-iodo-2'-deoxyuridine (IdUrd) caused a similar increase only in tk- cells (LMtk-, BHKtk-). In vivo and in vitro stabilization studies using a [35S]methionine pulse-chase experiment or heat inactivation studies with purified HSV-1 tk revealed that stabilization of tk by the analogues could not account for the extent of the observed increase. Since overproduction of tk is observed only at late times of infection, it is suggested that the presence of these thymidine analogues in either the viral DNA or the cellular nucleotide pools is responsible for the observed differential effects.

Animals↗
PubMed1986

Synthesis and biological activity of several amino nucleoside-platinum(II) complexes.

Several platinum(II) complexes of 3',5'-diamino-3',5'-dideoxythymidine (compound 1), 5'-amino-5'-deoxythymidine (compound 2), and 3'-amino-3'-deoxythymidine (compound 3) and the respective 2'-deoxyuridine amino nucleoside complexes, 4-6, have been synthesized. Whereas compounds 1, 2, and 4-6 had no inhibitory effect on the replication of murine L1210 cells in cell culture, compound 3 [(3'-AdThd)2PtCl2] inhibited these cells with an ED50 of 0.8 microM. Incubation of L1210 cells with 10-20 microM compound 3 for 2 h produced less than 18% inhibition of RNA, DNA, or protein synthesis, which is of questionable significance. However a 16-h incubation resulted in an increased uptake of labeled thymidine into DNA (77%), labeled uridine into RNA (17%), and labeled amino acids into protein (100%). These unexpected results indicate that inhibition of macromolecules may not be involved in the inhibition of the replication of L1210 cells. The increased incorporation of labeled metabolites into macromolecules may be related to the increase in cell volume after a 2-h incubation of L1210 cells with compound 3 plus a marked increase after 2 h in the proportion of cells in their S phase. Compound 3 appears to delay the progression of cells through their cell cycle. A marked inhibitory effect on the transport of methionine or aminoisobutyric acid into L1210 cells was found with compound 3, which was slightly greater than that produced with cisplatin. Compound 3 had a dose-dependent effect on the survival of mice bearing the L1210 ascites neoplasm, with a T/C X 100 of 175 at a dose of 320 mg/kg. Investigation of the kinetics of decomposition in aqueous systems demonstrated that the primary UV-absorbing decomposition product is 3'-amino-3'-deoxythymidine and that only a limited amount of the compound is formed (less than 8%). Although 3'-amino-3'-deoxythymidine could account for a part of the inhibition of the replication of L1210 cells in culture, it cannot account for the inhibition of amino acid transport by compound 3, the platinum complex of 3'-amino-3'-deoxythymidine. Compound 3 has been shown to limit part of the amino acid uptake into L1210 cells in a similar manner to cisplatin.

Amino Acids↗
PubMed1986

Antineoplastic activity of 3'-(chloroethyl)nitrosourea analogues of 2'-deoxyuridine and 2'-deoxy-5-fluorouridine.

The (chloroethyl)nitrosourea analogues of 2'-deoxyuridine and 2'-deoxy-5-fluorouridine, 3'-[3-(2-chloroethyl)-3-nitrosoureido]-2',3'-dideoxyuridine (3'-CdUNU, 7) and 3'-[3-(2-chloroethyl)-3-nitrosoureido]-2,3'-dideoxy-5-fluorouridine (3'-CFdUNU, 8), have been synthesized by treatment of the corresponding 3'-amino nucleosides with chloroethyl isocyanate, followed by nitrosation of the resulting ureas. Nucleoside nitrosoureas 7 and 8 exhibited marked anticancer activity against L1210 leukemia in tumor-bearing mice. At an optimum dosage level of 40 mg/kg, 7 and 8 produced 90% and 60% "cures" (greater than 60-day survivors), respectively. The structure-activity relationships are discussed.

Alkylation↗
PubMed1986

Synthesis and biological activity of 5-phenylselenenyl-substituted pyrimidine nucleosides.

Several 5-phenylselenenyl derivatives of pyrimidine nucleosides were synthesized by electrophilic addition of phenylselenenyl chloride to the nucleosides under basic conditions. With use of this route, 5-(phenylselenenyl)-6-azauracil was also prepared. These compounds may serve as inhibitors of thymidylate synthase, as potential antiviral and anticancer agents, and as versatile intermediates for the synthesis of 5- or 6-substituted nucleosides. 5-(Phenylselenenyl)arabinosyluracil (PSAU, 4) and the corresponding cytosine analogue (PSAC, 5) were poor inhibitors of a promyelocytic leukemia cell line that was arabinosylcytosine-resistant. PSAU and PSAC were significantly less active than ara-C against L1210 cells and were found to selectively interfere with the cellular uptake and/or phosphorylation of 2'-deoxycytidine and 2'-deoxyuridine in intact L1210 cells.

Animals↗
PubMed1985

Preparative and analytical high-performance liquid chromatographic methods in the synthesis and analysis of decomposition of nitrosourea nucleosides.

Details are given for reversed-phase, adsorption, and aqueous ammonia-modified adsorption high-performance liquid chromatographic systems developed to separate 3'-chloroethylnitrosourea analogues of thymidine, 2'-deoxyuridine, and 5-fluoro-2'-deoxyuridine from their decomposition products and synthetic precursors. The effect of varying the substituent at the 3'- and 5-position on relative retention in each system is discussed. These systems are used to purify intermediates in the synthesis of these potent antineoplastic agents, and for the simultaneous analysis of the nitrosourea nucleosides and their breakdown products in kinetic studies of their decomposition. Application of these methods to the analysis of the kinetics of the breakdown of these compounds is demonstrated, with detection limits (signal-to-noise ratio = 2) in the 1-2 ng range.

Chemical Phenomena↗