5-alkynyl analogs of arabinouridine and 2'-deoxyuridine: Cytostatic activity against herpes simplex virus and varicella-zoster thymidine kinase gene-transfected cells

A group of arabinouridines (TMSEAU, EAU, IEAU-TA) and 2'-deoxyuridines (TMSEDU, EDU, IEDU) having a variety of substituents at the uracil C-5 position (trimethylsilylethynyl, TMSE; ethynyl, E; or iodoethynyl, IE), and the sugar C-2' position (2'-arabino OH in arabinouridine, AU; or 2'-deoxyribo H in 2'-deoxyuridine, DU) were prepared to acquire antiviral structure-activity relationships. A broad-spectrum viral panel screen showed that these 5-alkynylarabino/deoxy-uridines exhibit moderate anti-HSV-1 activity, with no difference in potency between arabinouridines and 2'-deoxyuridines. The 2'-deoxyuridines TMSEDU, EDU, and IEDU, unlike the arabinouridines, exhibited potent antiviral activity against cytomegalovirus, but they were also highly cytostatic. The abilities of the 5-alkynylarabino/deoxy-uridines to inhibit nontransfected (wild-type or thymidine kinase-deficient, tk(-)) and viral gene transfected (HSV-1, HSV-2, or VZV thymidine kinase-positive, tk(+)) FM3A and OST (osteosarcoma) cells were determined. This group of 5-alkynylarabino/deoxy-uridines showed an enhanced ability to inhibit cells transfected with a viral thymidine kinase gene (HSV-1tk(+), HSV-2tk(+), VZVtk(+)) relative to wild-type or thymidine kinase-deficient (tk(-)) cells.