title: Induction of cell cycle-dependent cytotoxicity and apoptosis by new heterodinucleoside phosphate dimers of 5-fluorodeoxyuridine in PC-3 human prostate cancer cells.
abstract: Fluorodeoxyuridine (5-FdUrd) is an antineoplastic agent with clinical activity against different types of solid tumours. To enhance the effectiveness of this drug, we have synthesised new heterodinucleoside phosphate dimers of 5-FdUrd. These dimers were compared to 5-FdUrd for their cytotoxic effect and the cell cycle dependence of cytotoxicity, as well as for their capacity to induce apoptosis and inhibit thymidylate synthetase (TS) in androgen-independent human PC-3 prostate tumour cells. Incubation of the cells with the dimers N(4)-palmitoyl-2'-deoxycytidylyl-(3'-->5')-5-fluoro-2'-deoxyuri din e (dCpam-5-FdUrd) and 2'-deoxy-5-flourouridylyl-(3'-->5')-2'-deoxy-5-fluoro-N(4)-octa decylc ytidine (5-FdUrd-5-FdC18) resulted in a marked cytotoxicity with IC(50) values of 4 microM, similar to 5-FdUrd. In contrast to 5-FdUrd, 100% toxicity was achieved with concentrations of 100-200 microM 5-FdUrd-5-FdC18. Flow cytometric analysis revealed an increase in the cell population in S-phase after treatment with 5-FdUrd, 5-FdUrd-5-FdC18, and dCpam-5-FdUrd from 36 to 63%, 50%, and 77%, respectively. dCpam-5-FdUrd was more potent than 5-FdUrd in arresting the cell cycle. Significant S-phase arrest was indicated by a decreased proportion of cells in G1- and G2/M-phases. Cell cycle arrest and inhibition of cell proliferation were followed by apoptosis, as shown by a 6- to 8-fold increased binding of Apo2.7 antibody, a 9- to 11-fold increase in caspase-3 activity, DNA fragmentation, and by cell morphology showing the appearance of apoptotic bodies. Importantly, 5-FdUrd-5-FdC18 increased the number of apoptotic cells to 160% compared to 5-FdUrd under the same conditions. As with 5-FdUrd, the two dimers also inhibited TS in a time- and concentration-dependent manner, although requiring 100-fold higher concentrations. In conclusion, dCpam-5-FdUrd and 5-FdUrd-5-FdC18 exert stronger cytotoxicity and induce more S-phase arrest and apoptosis than does 5-FdUrd in PC-3 cells, suggesting their potential role in the treatment of human prostate cancer.
authors: Department of Pathology, University Hospital, CH-8091, Zürich, Switzerland.
authors: R M
authors: RM
authors: Cattaneo-Pangrazzi
authors: H
authors: H
authors: Schott
authors: H
authors: H
authors: Wunderli-Allenspach
authors: M
authors: M
authors: Derighetti
authors: R A
authors: RA
authors: Schwendener
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis; D002453:Cell Cycle / Q000187:drug effects; D002467:Cell Nucleus / Q000187:drug effects; D048429:Cell Size / Q000187:drug effects; D019281:Dimerization; D015226:Dinucleoside Phosphates / Q000494:pharmacology; D004354:Drug Screening Assays, Antitumor; D005467:Floxuridine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D008297:Male; D009838:Oligodeoxyribonucleotides / Q000494:pharmacology*; D011355:Prodrugs / Q000378:metabolism / Q000494:pharmacology; D011471:Prostatic Neoplasms / Q000188:drug therapy*; D013940:Thymidylate Synthase / Q000037:antagonists & inhibitors; D014407:Tumor Cells, Cultured
chemical_list: C408702:2'-deoxy-5-fluorouridylyl-(3'-5')-2'-deoxy-5-fluoro-N(4)-octadecylcytidine; D000970:Antineoplastic Agents; D015226:Dinucleoside Phosphates; C408701:N(4)-palmitoyl-2'-deoxycytidylyl-(3'-5')-5-fluoro-2'-deoxyuridine; D009838:Oligodeoxyribonucleotides; D011355:Prodrugs; D005467:Floxuridine; D013940:Thymidylate Synthase