Disaccharide Pyrimidine Nucleosides and Their Derivatives: A Novel Group of Cell-Penetrating Inhibitors of Poly(ADP-Ribose) Polymerase 1

Abstract

Nearly 30 synthetic nucleosides were tested with human recombinant poly(ADP-ribose) polymerase 1 as potential inhibitors of this enzyme. The most active compounds were some disaccharide analogues of thymidine: 3′-O-β-D-ribofuranosyl-5-iodo-dUrd (2d; IC50 = 45 μM), 3′-O-β-D-ribofuranosyl-2′-deoxythymidine (2e; IC50 = 38 μM), and 3′-O-β-D-ribofuranosyl-2′-deoxythymidine oxidized (4; IC50 = 25 μM). These compounds also reduced H2O2-induced synthesis of poly(ADP-ribose) in cultured human ovarian carcinoma (SKOV-3) cells in a dose-dependent manner. Furthermore, compounds 2d or 2e until a concentration of 1 mM did not affect growth of SKOV-3 cells, whereas dialdehyde compound 4, as well as thymidine, exhibited a significant cytotoxicity.