Synthesis of 2'-deoxyuridine and 5-fluoro-2'-deoxyuridine derivatives and evaluation in antibody targeting studies.
Derivatives of 2'-deoxyuridine and of the anticancer agent 5-fluoro-2'-deoxyuridine (FdUR) were linked indirectly via a human serum albumin carrier (HSA) to the murine antiosteosarcoma monoclonal antibody 791T/36. Starting from the 2'-deoxyuridines 1a and 1b, the new nucleosides containing 5'-succinamic acid 7 and 5'-maleamic acid 8 spacers were synthesized from the key intermediate 5'-aminonucleoside 4, and the ribofuronamidobenzoic acid 13 from ribofuranuronic acid 10. These nucleosides were linked via their spacer functionality to HSA. High molar substitution ratios (MSR: moles of drug/mole of HSA) of 25-40 for these derivative-HSA conjugates were achieved. All derivatives were less cytotoxic than the parent drug against both antigen positive osteogenic sarcoma 791T and antigen negative bladder carcinoma T24 cell lines; no IC50 was achieved with any derivative against 791T cells. The fluorodeoxyuridine-HSA conjugates were then further linked via a stable thioether bond to the mouse monoclonal antibody 791T/36. The optimum fluorinated 5'-succinamic acid immunoconjugate exhibited an IC50 of 1 microM against 791T and T24 cells, slightly better than that of fluorodeoxyuridine. The unconjugated derivative 7 was much less cytotoxic than immunoconjugate, with an IC50 of 62 microM on T24 cells, and failed to reach 50% inhibition of 791T cell growth at 290 microM concentration. Derivative 7-HSA conjugate was 10-fold less cytotoxic than the immunoconjugate against both cell lines. Immunoconjugates synthesized with the other 5-fluoro derivatives were unable to effect 50% inhibition of growth of cell lines. Nonfluorinated derivatives and their HSA conjugates and immunoconjugates exhibited no cytotoxicity.
Cancer Research Campaign Laboratories, University of Nottingham, University Park, U.K.
T F
TF
Henn
M C
MC
Garnett
S R
SR
Chhabra
B W
BW
Bycroft
R W
RW
Baldwin
D000911:Antibodies, Monoclonal / Q000737:chemistry; D000912:Antibodies, Neoplasm / Q000737:chemistry; D000964:Antimetabolites, Antineoplastic / Q000138:chemical synthesis* / Q000494:pharmacology; D003857:Deoxyuridine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000494:pharmacology; D004354:Drug Screening Assays, Antitumor; D005467:Floxuridine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000494:pharmacology; D006801:Humans; D012709:Serum Albumin / Q000737:chemistry; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D000912:Antibodies, Neoplasm; D000964:Antimetabolites, Antineoplastic; D012709:Serum Albumin; D005467:Floxuridine; D003857:Deoxyuridine