N-(adamantyl-1)methyl, N-(adamantyl-2), and N-(omega-aminodecyl) amides of vancomycin, eremomycin, and dechloroeremomycin aglycons and their des-(N-Me-D-Leu) derivatives were synthesized and their antibacterial and anti-HIV activities were investigated. Carboxamides with an intact peptide core demonstrated activity against glycopeptide-susceptible and -resistant bacteria (1-32 microM). N-(adamantyl-1)methylcarboxamide of eremomycin aglycons had good antiretroviral activity (1.6 microM against HIV-1). Compounds with destroyed peptide core [des-(N-Me-D-Leu)-aglycon amides] were inactive against both glycopeptide-sensitive and -resistant bacteria. (Adamantyl-1)methylamide of des-(N-Me-D-Leu)-eremomycin aglycon had good antiretroviral activity (EC50 of 5.5 microM for HIV-1 and 3.5 microM for HIV-2). (Adamantyl-1)methylamides of eremomycin aglycon and its des-(N-Me-d-Leu)-derivative are the most promising and selective antiretroviral agents. Their ability to induce bacterial resistance to glycopeptide antibiotics during prolonged administration may be expected to be very low or absent. This might make the use of these derivatives feasible in the prolonged therapy or prophylaxis of HIV infections.
Anno 2015, the race for developing the ideal therapy, or what is now called "cure," for hepatitis C virus infection has continued unabatedly. The targets (NS3/4A protease, NS5A protein, and NS5B polymerase) have remained the same, and the number of compounds [direct-acting antivirals (DAAs)] interacting with these targets has continued to increase. Whereas pan-genotypic activity has remained a mandatory requirement, the problem of virus drug resistance has become less crucial. The need for combining DAAs acting at different sites has remained compelling, with the drugs used for combinations emanating from the same pharmaceutical company, that is, Gilead (sofosbuvir and ledipasvir) (Gilead Sciences, Foster City, CA, USA) (AbbVie, North Chicago, IL, USA), AbbVie (ABT/r, ombitasvir, and dasabuvir), and BMS (Bristol-Myers Squibb), (New York City, NY, USA) (asunaprevir and daclatasvir) among the leading contenders. At stake is the definitive cure of HCV infection [as reflected by a sustained viral response (SVR) after 12 weeks of treatment]. This SVR is expected to reduce cirrhosis and hepatocellular carcinoma, two complications inherently linked to HCV infection. Unlike hepatitis B virus and human immunodeficiency virus, HCV infection can be definitely and permanently cured by antiviral therapy because HCV has no long-term reservoir in the body. Peginterferon combined with ribavirin and even the first-wave protease inhibitors telaprevir and boceprevir now belong to the milestones that had an important, although historical, role in the final conquest of hepatitis C.
No abstract is provided for this article.
The acyclic nucleoside phosphonate HPMPC [( S )-1-[3-hydroxy-2-(phosphonomethoxy)propyl]cytosine, cidofovir, Vistide ® ] has a unique profile among the antiviral agents in that it is active against a much broader spectrum of DNA viruses than any other antiviral agent, and, furthermore, shows a long-lasting antiviral activity, thus enabling infrequent dosing (for intravenous administration, as infrequent as once a week or every other week). HPMPC owes its antiviral activity to a selective inhibitory effect on viral DNA synthesis: as has been demonstrated for human cytomegalovirus (CMV), HPMPC leads to DNA chain termination following the incorporation of two consecutive HPMPC residues. The activity spectrum of HPMPC encompasses herpes-, adeno-, polyoma-, papilloma-, and poxviruses. It has been approved for the treatment of CMV retinitis in AIDS patients and has proved effective in the treatment of herpes simplex virus (HSV) infections (particularly those that are resistant to acyclovir), human papilloma virus (HPV) infections ( e.g. anogenital warts and recurrent laryngeal papillomatosis) and poxvirus infections ( e.g. molluscum contagiosum). It is now further explored for its therapeutic potential in the treatment of HSV, CMV and HPV infections, and various other DNA virus infections, including adenovirus infections ( e.g. keratoconjunctivitis), polyomavirus infections such as PML (progressive multifocal leukoencephalopathy), poxvirus infections ( e.g. molluscum contagiosum), Epstein-Barr virus (EBV)-associated infections, and human herpesvirus type 8 (HHV-8)-associated infections ( e.g. Kaposi's sarcoma).
Strong hydrogen-bonding forces between the Thr26 and Thr26′of the protease stabilize the internal cage of the dimeric triad of the aspartyl HIV-1 protease (Asp25Thr26Gly27 and Asp25′Thr26′Gly27′, respectively). The interaction of reversible inhibitors of HIV-1 protease is based on (i) strong hydrogen-bonding forces between the main chain (─CONH─) oxygen atoms of Gly27 and/or Gly27′and hydrogen-bond donating moieties of a drug, and (ii) hydrogen bonds between the oxygen of the catalytic Asp25 and/or Asp25′carboxylates and aliphatic hydroxyl groups of a drug. The free entry of natural substrates into the active-site cavity is sterically hindered by inhibitors, so that the catalytic Asp carboxylates cannot interact with natural substrates. Irreversible inhibitors interact with the nucleophilic carboxylate moiety of Asp25 of HIV-1 protease by covalent bonding.
The reverse transcriptase (RT) of the human immunodeficiency virus type 1 (HIV-1) is composed of two subunits of 66 and 51 kDa in a 1 to 1 ratio. Because dimerization is a prerequisite for enzymatic activity, interference with the dimerization process could constitute an alternative antiviral strategy for RT inhibition. Here we describe an in vitro assay for the study of the dimerization state of HIV-1 reverse transcriptase based on chemical crosslinking of the subunits with dimethylsuberimidate. Crosslinking results in the formation of covalent bonds between the subunits, so that the crosslinked species can be resolved by denaturing gel electrophoresis. Crosslinked RT species with molecular weight greater than that of the dimeric form accumulate during a 1-15-min time course. Initial evidence suggests that those high molecular weight species represent trimers and tetramers and may be the result of intramolecular crosslinking of the subunits of a higher-order RT oligomer. A peptide that corresponds to part of the tryptophan repeat motif in the connection domain of HIV-1 RT inhibits crosslink formation as well as enzymatic activity. The crosslinking assay thus allows the investigation of the effect of inhibitors on the dimerization of HIV-1 RT.
