JAC Advance Access originally published online on November 22, 2006
Journal of Antimicrobial Chemotherapy 2007 59(1):80-86; doi:10.1093/jac/dkl454
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Pronounced in vitro and in vivo antiretroviral activity of 5-substituted 2,4-diamino-6-[2-(phosphonomethoxy)ethoxy] pyrimidines
21 Rega Institute for Medical Research, K.U.Leuven B-3000 Leuven, Belgium 2 Centre for New Antivirals and Antineoplastics, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic 166 10 Praha, Czech Republic
Received 29 June 2006; returned 12 September 2006; revised 14 September 2006; accepted 10 October 2006
*Corresponding author. Tel: +32-16-33-73-52; Fax: +32-16-33-73-40; E-mail: jan.balzarini{at}rega.kuleuven.be
Objectives: To discover new potent and selective anti-human immunodeficiency virus (HIV) acyclic nucleoside phosphonate (ANP) drugs with in vivo antiretroviral activity.
Methods: New acyclic pyrimidine nucleoside phosphonate derivatives that mimic the structure of the anti-HIV purine nucleoside phosphonates 9-(2-phosphonylmethoxyethyl)adenine (PMEA, adefovir) and (R)-9-(2-phosphonylmethoxypropyl)adenine (PMPA, tenofovir) were designed by linking the acyclic side chain of the ANPs through an ether bond to the C-6 position instead of the N-1 position of the pyrimidine ring. The compounds were evaluated against HIV and Moloney murine sarcoma virus (MSV) in cell culture, including a broad variety of HIV-1 clade clinical isolates and relevant mutant (drug-resistant) HIV-1 isolates. Their antiviral activities were correlated and investigated in an in vivo model consisting of MSV-infected newborn mice. MSV-induced tumour formation and associated death were recorded in drug-treated animals.
Results: Several 5-substituted 6-[2-(phosphonomethoxy)ethoxy]-2,4-diaminopyrimidine (PMEO-DAPy) analogues were found to inhibit a broad variety of HIV-1 clinical isolates. They showed a more favourable cross-resistance profile to mutant virus isolates than adefovir and tenofovir. There was a close correlation between inhibition of MSV in C3H/3T3 cells and inhibition of HIV-1 in CEM cells. The PMEO-DAPy derivatives potently inhibited MSV-induced tumour cell formation in newborn mice. The 5-methyl analogue PMEO-5-Me-DAPy proved markedly more inhibitory to MSV-induced tumour cell formation and associated animal death than its unsubstituted parent PMEO-DAPy derivative. When compared with adefovir, PMEO-5-Me-DAPy was less toxic and more antivirally active in MSV-infected mice.
Conclusions: PMEO-5-Me-DAPy deserves further (pre)clinical investigations as a candidate anti-HIV drug.
Keywords: HIV , MSV , acyclic nucleoside phosphonates , ANP , antiretroviral drugs , PMEO-DAPy