title: Folate-based inhibitors of thymidylate synthase: synthesis and antitumor activity of gamma-linked sterically hindered dipeptide analogues of 2-desamino-2-methyl-N10-propargyl-5,8-dideazafolic acid (ICI 198583).
abstract: In an effort to synthesize inhibitors of thymidylate synthase (TS) that do not undergo polyglutamation, a series of gamma-linked sterically hindered dipeptide analogues of 2-desamino-2-methyl-N10-propargyl-5,8-dideazafolic acid (ICI 198583) was prepared. A methyl, ethyl, or propargyl group was incorporated into the gamma-glutamyl amide bond of gamma-linked L,L dipeptide derivatives of ICI 198583, such as ICI 198583-gamma-L-Glu. In addition, steric bulk was introduced on either side of the gamma-glutamyl bond of ICI 198583-gamma-L-Glu or ICI 198583-gamma-L-Ala. The resulting dipeptide analogues, e.g., ICI 198583-gamma-MeGlu and ICI 198583-gamma-Aib, were apparently stable to in vivo hydrolysis but poorer inhibitors of TS and L1210 cell growth. However, introduction of 7-Me, 2'-F substitution into the quinazoline nucleus gave significant improvement in the inhibitory activity against thymidylate synthase. Compounds 28-30, the 7-Me, 2'-F derivatives of ICI 198583-gamma-MeGlu, ICI 198583-gamma-EtGlu, and ICI 198583-gamma-PgGlu, respectively, were potent inhibitors of TS (K(iapp) = 0.21-1.1 nM) and L1210 cell growth (IC50 = 0.05-0.34 microM) and were similar to that seen with the most potent gamma-linked L,D dipeptide derivatives of ICI 198583 previously synthesized. Furthermore, the low cross-resistance ratios for the L1210:R(D1694)/L1210 cell line indicated that 28-30 do not undergo polyglutamation.
authors.affiliation: CRC Centre for Cancer Therapeutics at The Institute of Cancer Research, Cancer Research Campaign Laboratories, Sutton, Surrey, England.
authors.forename: V
authors.initials: V
authors.lastname: Bavetsias
authors.forename: A L
authors.initials: AL
authors.lastname: Jackman
authors.forename: J H
authors.initials: JH
authors.lastname: Marriott
authors.forename: R
authors.initials: R
authors.lastname: Kimbell
authors.forename: W
authors.initials: W
authors.lastname: Gibson
authors.forename: F T
authors.initials: FT
authors.lastname: Boyle
authors.forename: G M
authors.initials: GM
authors.lastname: Bisset
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects; D004151:Dipeptides / Q000138:chemical synthesis* / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D005492:Folic Acid / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D007939:Leukemia L1210 / Q000473:pathology; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D051379:Mice; D013940:Thymidylate Synthase / Q000037:antagonists & inhibitors*
chemical_list: D000970:Antineoplastic Agents; D004151:Dipeptides; D004791:Enzyme Inhibitors; D005492:Folic Acid; D013940:Thymidylate Synthase; C059966:ICI 198583