Publications

9-(2-Phosphonylmethoxyethyl)adenine (PMEA), a potent inhibitor of human immunodeficiency virus (HIV), caused a dose-dependent suppression of tumor formation, and mortality associated therewith, in 6-day-old NMRI mice inoculated intracerebrally with Moloney murine sarcoma virus (MSV). Even at a dose as low as 1 mg/kg/day, PMEA effected a significant delay in tumor formation. When evaluated in parallel with PMEA, 3'-azido-2',3'-dideoxythymidine (AZT) conferred a comparable tumor-inhibitory effect at a 5- to 10-fold higher dose than PMEA. Prolonged treatment of MSV-infected mice with PMEA resulted in long-term survivors without apparent signs of tumor development. In view of the propensity of HIV to spread to the central nervous system (CNS), the marked activity shown by PMEA against experimental retrovirus infection of the brain in mice points to its potential in the treatment of AIDS and other retrovirus infections of the CNS.

Various 2-arylideneindanones 1, 2-arylidenetetralones 2, and 2-arylidenebenzosuberones 3 were synthesized with the aim of determining the relative orientations of the two aryl rings which favored cytotoxicity. Molecular modeling of the unsubstituted compound in each series revealed differences in the spatial arrangements of the two aryl rings, and evaluation of these compounds against P388, L1210, Molt 4/C8, and CEM cells as well as a panel of human tumor cell lines indicated that in general the order of cytotoxicity was 3 > 2 > 1. In particular 2-(4-methoxyphenylmethylene)-1-benzosuberone (3k) had the greatest cytotoxicity, possessing 11 times the potency of the reference drug melphalan when all five screens were considered. Series 3 was considered in further detail. First, excision of the aryl ring fused to the cycloheptanone moiety in series 3 led to some 2-arylidene-1-cycloheptanones 4 which had approximately one-third of the bioactivity of the analogues 3. Second, in some screens cytotoxicity was correlated negatively with the sigma values and positively with the MR constants of the substituents in the arylidene aryl ring of 3. Third, X-ray crystallography of five representative compounds (3i,k-n) revealed differences in the locations of the aryl rings which may have contributed to the variations in cytotoxicity. Finally three members of series 3 inhibited RNA and protein syntheses and induced apoptosis in human Jurkat T cells. This study has revealed that 2-arylidene-1-benzosuberones are a group of useful cytotoxic agents, and in particular 3k serves as a prototypic molecule for subsequent structural modifications.

Several new analogues of the novel anti-HIV agent cosalane have been synthesized and evaluated as inhibitors of HIV-1 integrase and protease, HIV-1 replication, HIV-1 and HIV-2 cytopathicity, HIV-1- and HIV-2-mediated syncytium formation, and cytopathicity of a variety of human pathogenic viruses. The congeners displayed enhanced potencies relative to cosalane itself as inhibitors of HIV-1 integrase and protease. The two most potent analogues against HIV-1 integrase displayed IC50 values of 2.2 microM, while the three most potent compounds against HIV-1 protease had IC50 values in the 0.35-0.39 microM range. In addition to its activity against HIV-1 and HIV-2 cytopathicity, cosalane inhibited the cytopathic effects of herpes simplex virus-1, herpes simplex virus-2, and human cytomegalovirus at concentrations that were well below the cytotoxic concentrations. Potentially useful antiviral activities were also revealed for some of the new cosalane congeners against influenza virus, Junin virus, and Tacaribe virus.

Starting from 3-O-mesyl-1,2-O-isopropylidene-alpha-D-allofuranose (9) the anomeric mixtures of the requisite carbohydrates 1,2-di-O-acetyl-6-O-benzoyl-5-deoxy-3-O-mesyl-D-allofuranoses++ + 17A alpha/beta, 1,2-di-O-acetyl-5,6-di-O-benzoyl-3-O-mesyl-D-allofuranoses 17B alpha/beta, and 1,2-di-O-acetyl-5,6-di-O-benzoyl-3-O-mesyl-L-talofuranoses 17C alpha/beta were synthesized. 1,2-Di-O-acetyl-5-O-benzoyl-6-deoxy-3-O-mesyl-D-allofuranoses++ + 17D alpha/beta and the corresponding L-talofuranoses 17E alpha/beta were obtained from 6-deoxy-3,5-di-O-benzoyl-1,2-O-isopropylidene-alpha-D- allofuranose (12) and the corresponding beta-L-talofuranose 13. Coupling of these sugar derivatives with thymine gave the beta-nucleoside derivatives 18A-E. Treatment of compounds 18A-E with DBU produced the corresponding 2,3'-anhydro nucleosides 19A-E with a free 2'-OH group. After deoxygenation of 2'-O-[[(4-methylphenyl)oxy]thiocarbonyl] compounds 20A-E with tributyltin hydride the 2,3'-anhydro bridge of the 2'-deoxynucleosides 21A-E was opened with LiN3 to produce the protected 3'-azido-2,3'-dideoxynucleoside derivatives 22A-G. Saponification with NaOCH3 gave 1-(3'-azido-2',3',5'-trideoxy-beta-D-allofuranosyl)thymine (2; homo-AZT), the 5'-C-(hydroxymethyl) derivatives of AZT 1-(3'-azido-2',3'- dideoxy-beta-D-allofuranosyl)thymine (3) and 1-(3'-azido-2',3'-dideoxy-alpha-L-talofuranosyl)thymine (4), and the 5'-C-methyl derivatives of AZT 1-(3'-azido-2',3',6'-trideoxy-beta-D-allofuranosyl)thymine (5) and 1-(3'-azido-2',3',6'-trideoxy-alpha-L-talofuranosyl)thymine (6). Compounds 2-6 were evaluated for their inhibitory effect on human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2) replication in MT-4 cells and found inactive at subtoxic concentrations. Compounds 2-4 and 6 are not effective against herpes simplex virus type 1 (HSV-1) and type 2 (HIV-2), vaccinia virus (VV), and vesicular stomatitis virus (VSV) at 400 micrograms/mL. 5 is slightly active against HSV-1, HSV-2 and VV at 150, 300, and 300 micrograms/mL, respectively.

A synthetic gene encoding for HIV‐1 integrase was designed to circumvent the intrinsic instability and the repressor elements present in the wild‐type gene. High‐level expression of HIV‐1 integrase was obtained in various human cell lines independently of viral accessory proteins. A human 293T cell line was selected that stably expresses HIV‐1 integrase and has growth kinetics comparable to the parental cell line. The enzyme was localized in the nucleus and remained stably associated with the chromosomes during mitosis. Lentiviral vector particles carrying the inactivating D64V mutation in the integrase gene were capable of stably transducing 293T cells when complemented in the producer cells with integrase expressed from the synthetic gene. When the cell line that stably expresses integrase was infected with the defective viral particles, complementation of integrase activity was detected as well. Expression of active HIV‐1 integrase in human cells will facilitate the study of the interplay between host and viral factors during integration.—Cherepanov, P., Pluymers, W., Claeys, A., Proost, P., De Clercq, E., Debyser, Z. High‐level expression of active HIV‐1 integrase from a synthetic gene in human cells. FASEB J. 14, 1389–1399 (2000)

Selective Laser Melting (SLM) is an Additive Manufacturing (AM) technique in which a part is built up in a layer- by-layer manner by melting the top surface layer of a powder bed with a high intensity laser according to sliced 3D CAD data. In this work, mechanical properties like tensile strength, elongation, Young's modulus, impact toughness and hardness are investigated for SLM-produced AlSi10Mg parts, and compared to conventionally cast AlSi10Mg parts. It is shown that AlSi10Mg parts with mechanical properties comparable or even exceeding to those of conventionally cast AlSi10Mg can be produced by SLM.

Abstract We have demonstrated that thymidylate synthase (TS) activity is enhanced by more than 10- to 20-fold in HCMV-infected HEL cells as compared to non-infected cells. The increase in TS activity was found (i) to parallel the progression of the viral cytopathic effect over a 5-days period, (ii) to be independent of viral DNA synthesis and to result from an early event in the viral replicative cycle. Several compounds known to be targeted at TS, such as 5-fluoro-dUrd, 5-trifluoromethyl-dUrd, and 5-formyl-dUrd, inhibited TS activity in HCMV-infected cells and, concomitantly, displayed HCMV activity. The exact impact of inhibition of TS activity in the overall anti-HCMV activity of the test compounds remains however to be determined.

sponsorship: The authors acknowledge the kind help of Mr. A. Madhukar Reddy, Secretary and Correspondent, S.R. College of Pharmacy, Warangal, India for providing laboratory facilities for the present research work and the technical assistance of Mrs. Leentje Persoons, Mrs. Lies Van den Heurck, Mr. Steven Carmans and Mrs. Anita Camps was greatly appreciated. The antiviral/cytostatic assays were supported by the KU Leuven (GOA 10/14). (KU Leuven|GOA 10/14)

A series of novel 1,2,4-triazole derivatives has been designed and synthesized. All of the new compounds were evaluated for their anti-HIV activities in MT-4 cells. Three of them showed moderate activities against wild-type HIV-1 with an EC50 ranging from 17.4 μM to 4.87 μM. Among the active compounds, 3-((4-(3,4-dimethoxybenzylideneamino)- 5-(furan-2-yl)-4H-1,2,4-triazol-3-ylthio)methyl)benzonitrile (4d) was identified as the promising compound (EC50 = 17.4 μM, SI =13). However, no compound displayed inhibitory activity against HIV-2. Keywords: HIV-1, AIDS, NNRTIs, Triazoles, Synthesis, Anti-HIV-1 activity, NNRTIs, LC Autosampler Device, heterocyclic scaffold, Nexus 470FT-IR

We have recently reported the discovery of an entirely new category of potent antivaricella-zoster virus agents based on novel deoxynucleoside analogues bearing unusual fluorescent bicyclic furo base moieties. Initial studies revealed an absolute requirement of a long alkyl side-chain, with an optimal length of C8-C10, for antiviral activity. However, the impact of this requirement on the physical properties of these compounds is high: inherent lipophilicity and extremely poor aqueous solubility, which may limit the use of these nucleosides as drugs. In order to address this issue, we have now prepared a new series of analogues, bearing ether and glycol type side-chains, designed to improve the aqueous solubility of the compounds. Synthesis of target nucleosides involved Pd-catalysed coupling of terminal alkynes with 5-iodo-2'-deoxyuridine. The 5-alkynyl nucleosides thus obtained were then treated with copper (I) iodide to produce the desired bicyclic analogues. As anticipated, the new compounds exhibited a dramatic increase in aqueous solubility, although antiviral activity was significantly reduced. A possible correlation between antiviral activity and overall compound lipophilicity is discussed.