Activities of Masked 2′,3′-Dideoxynucleoside Monophosphate Derivatives against Human Immunodeficiency Virus in Resting Macrophages

Abstract

The anti-human immunodeficiency virus (HIV) activity of aryloxyphosphoramidate protides of a number of anti-HIV nucleoside analogues was assessed in resting primary monocyte-macrophages (M/M). While 2,3-dideoxythymidine (d4T), 2,3-dideoxyadenosine (ddA), and 2,3-dideoxy-2,3-didehydroadenosine (d4A) protides showed an anti-HIV activity that was 25-to 625-fold greater than the parent nucleotides d4T, ddA, and d4A, respectively, other aryloxyphosphoramidate protides showed similar or even lower anti-HIV activities than their parent compounds. This variable anti-HIV effect is most likely related to the different dynamics of intracellular nucleoside monophosphate release from the protides. Our results indicate the potential advantage of therapeutic use of this approach for some nucleotide analogues to affect HIV replication in M/M, one of the major reservoirs of HIV in vivo.In all body compartments, resting monocyte-macrophages (M/M) can be infected by human immunodeficiency virus (HIV) (1, 12-14, 27, 34, 37). Because of their resistance to the cytopathic effect of the virus, M/M are considered the most relevant reservoir of HIV in the body (10,18,26,31) and a crucial target for a successful therapeutic approach (2,3,35).M/M are characterized by some cellular peculiarities that affect not only virus replication (6, 28; S. Aquaro, P. Bagnarelli, M. Clementi, T. Guenci, R. Calio', and C. F. Perno, Program Abstr. 6th Conf. Retrovir. Opportunistic Infect., abstr. 607, 1999.) but also the activity of antiviral drugs (31, 33). Indeed, their resting status, and thus their limited DNA synthesis, does not require, for physiological functions, high intracellular levels of 2Ј-deoxynucleotide pools. As a consequence, and despite the limited phosphorylation of anti-HIV nucleoside analogues typically found in M/M, the ratio of the triphosphate forms of nucleoside reverse transcriptase inhibitors (NRTIs) to their natural triphosphorylated 2Ј-deoxynucleotide counterparts is higher than that found in lymphocytes (4). Thus, not surprisingly, the currently approved NRTIs for clinical use, i.e., azidothymidine (AZT), 2Ј,3Ј-dideoxyinosine, 2Ј,3Ј-dideoxycytidine (ddC), (Ϫ)(L)-3Ј-thia-2Ј,3Ј-dideoxycytidine (3TC), 2Ј,3Ј-didehydro-2Ј,3Ј-dideoxythymidine (d4T), show anti-HIV efficacies in M/M greater than those found in lymphocytes (4).Despite this increased anti-HIV efficacy in M/M, the in vivo antiviral activity of most NRTIs in sequestered compartments is still suboptimal for a number of reasons, including the limited penetration of most NRTIs in sanctuaries (11, 16) and the high expression of p170 glycoprotein in M/M (17), that may affect the overall intracellular drug concentrations in M/M. Therefore, attempts should be made to increase the intracellular concentration of the triphosphate forms of the NRTIs in M/M.To conveniently bypass the first phosphorylation step of NRTIs, masked nucleoside 5Ј-monophosphate (MP) prodrugs have been synthesized. These compounds were designed to act as monophosphorylated membrane-soluble prodrugs of the ...

Inhibition of Human Immunodeficiency Virus Replication by a Dual CCR5/CXCR4 Antagonist

“…For HIV-2 p27 Ag detection, the INNOTEST from Innogenetics (Temse, Belgium) was used. Human primary monocytes/macrophages (M/M) were obtained by previously published procedures (2,48). Briefly, PBMCs were separated by Ficoll-Hypaque gradient and seeded in plastic 48-well plates (Costar, Cambridge, Mass.)…”

Phosphoramidates and phosphonamidates (ProTides) with antiviral activity

“…As part of research project (sponsored by GlaxoSmithKline in Research Triangle Park North Carolina) devoted to discover anti-HIV and anti-HBV agents, McGuigan’s team applied the ProTide approach to 2′,3′-didehydro-2′,3′-dideoxyadenosine and other 2′,3′-dideoxy nucleosides including 2′,3′-dideoxyuridine, -adenosine, -3′-fluoroadenosine, -uridine 147–153 and also to the carbocyclic nucleoside ABC [11] with significant enhancement of its antiviral activity. 154 Phosphoramidates of other carbocyclic nucleosides were also explored such as carbocyclic adenosine derivatives and 2′,3′-dideoxy-2′3′-didehydro-7-deazaadenosine and they were shown to possess potent antiviral activity against HIV and HBV.…”

An Introduction to Nucleoside and Nucleotide Analogues

“…For example, highly variable anti-HIV activities in vitro have been observed for aryloxyphosphoramidate-substituted nucleoside analogues. Activity varied with target cell line, the endogenous nucleoside being mimicked and individual analogue structure, and was most probably related to the extent of unmasking activity to release the monophosphate [37].…”