title: Prodrugs of thymidylate synthase inhibitors: potential for antibody directed enzyme prodrug therapy (ADEPT).
abstract: Prodrugs of quinazoline antifolate thymidylate synthase (TS) inhibitors have been designed and synthesized for use in antibody-directed enzyme prodrug therapy (ADEPT). The syntheses of the alpha-linked dipeptides of two potent thymidylate synthase inhibitors, ZD1694 [N-[5-[N-(3,4-dihydro-2-methyl-4-oxoquinazolin-6- ylmethyl)-N-methylamino]-2-thenoyl]-L-glutamic acid] and ICI198583 ¿N-[4-[N-[(2-methyl-3,4-dihydro-4-oxo-6-quinazolinyl) methyl]-N-prop-2-ynylamino]benzoyl]-L-glutamic acid¿ are described. The alpha-carboxyl of the glutamic acid has been linked through an amide bond to an L-alanine or an L-glutamic acid. The alpha-linked L-dipeptide prodrugs were designed to be activated to their corresponding thymidylate synthase inhibitors at a tumour site by prior administration of a monoclonal antibody conjugated to the enzyme carboxypeptidase A (CPA). The viability of a colorectal cell line was monitored with the potential prodrugs in the presence or absence of CPA or with the parent drugs alone. All the dipeptides had greatly decreased cytotoxicity, with a deactivation of approximately 100-fold for the ZD1694 prodrugs and approximately 20-200-fold for the ICI198583 prodrugs. Activation of the alpha-linked L-alanine dipeptides with CPA led to a cytotoxicity enhancement of approximately 10-100 fold.
authors.affiliation: CRC Centre for Cancer Therapeutics, Institute of Cancer Research, Sutton, Surrey, UK.
authors.forename: C J
authors.initials: CJ
authors.lastname: Springer
authors.forename: V
authors.initials: V
authors.lastname: Bavetsias
authors.forename: A L
authors.initials: AL
authors.lastname: Jackman
authors.forename: F T
authors.initials: FT
authors.lastname: Boyle
authors.forename: D
authors.initials: D
authors.lastname: Marshall
authors.forename: R B
authors.initials: RB
authors.lastname: Pedley
authors.forename: G M
authors.initials: GM
authors.lastname: Bisset
mesh_terms: D000970:Antineoplastic Agents / Q000138:chemical synthesis / Q000494:pharmacology*; D001711:Biotransformation; D002268:Carboxypeptidases / Q000378:metabolism; D043422:Carboxypeptidases A; D016503:Drug Delivery Systems; D004354:Drug Screening Assays, Antitumor; D004791:Enzyme Inhibitors / Q000138:chemical synthesis / Q000494:pharmacology*; D005492:Folic Acid / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000494:pharmacology; D006801:Humans; D011355:Prodrugs / Q000138:chemical synthesis / Q000494:pharmacology*; D011799:Quinazolines / Q000138:chemical synthesis / Q000494:pharmacology*; D013876:Thiophenes / Q000138:chemical synthesis / Q000494:pharmacology*; D013940:Thymidylate Synthase / Q000037:antagonists & inhibitors*; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; D004791:Enzyme Inhibitors; D011355:Prodrugs; D011799:Quinazolines; D013876:Thiophenes; D005492:Folic Acid; D013940:Thymidylate Synthase; D002268:Carboxypeptidases; D043422:Carboxypeptidases A; C068874:raltitrexed; C059966:ICI 198583