Design and synthesis of dually branched 5'-norcarbocyclic adenosine phosphonodiester analogue as a new anti-HIV prodrug

Phosphonate prodrugs: an overview and recent advances

Phosphonates, often used as isosteric replacements for phosphates, can provide important interactions with an enzyme. Due to their high charge at physiological pH, however, permeation into cells can be a challenge. Protecting phosphonates as prodrugs has shown promise in drug delivery. Thus, a variety of structures and cleavage/activation mechanisms exist, enabling release of the active compound. This review describes the structural diversity of these pro-moieties, relevant cleavage mechanisms and recent advances in the design of phosphonate prodrugs.

Prodrugs of phosphonates and phosphates: crossing the membrane barrier

A substantial portion of metabolism involves transformation of phosphate esters, including pathways leading to nucleotides and oligonucleotides, carbohydrates, isoprenoids and steroids, and phosphorylated proteins. Because the natural substrates bear one or more negative charges, drugs that target these enzymes generally must be charged as well, but small charged molecules can have difficulty traversing the cell membrane by means other than endocytosis. The resulting dichotomy has stimulated a great deal of effort to develop effective prodrugs, compounds that carry little or no charge to enable them to transit biological membranes, but able to release the parent drug once inside the target cell. This chapter presents recent studies on advances in prodrug forms, along with representative examples of their application to marketed and developmental drugs.

Blocking of exchange proteins directly activated by cAMP leads to reduced replication of Middle East respiratory syndrome coronavirus

The outbreak of Middle East respiratory syndrome coronavirus (MERS-CoV) infections and diseases represents a potential threat for worldwide spread and requires development of effective therapeutic strategies. In this study, we revealed a novel positive function of an exchange protein directly activated by cyclic AMP 1 (cAMP-1; Epac-1) on MERS-CoV replication. Specifically, we have shown that Epac-specific inhibitor treatment or silencing Epac-1 gene expression rendered cells resistant to viral infection. We believe Epac-1 inhibitors deserve further study as potential therapeutic agents for MERS-CoV infection.