DL-β,β-Difluoroglutamic Acid Mediates Position-Dependent Enhancement or Termination of Pteroylpoly(γ-Glutamate) Synthesis Catalyzed by Folylpolyglutamate Synthetase

Exploitation of folate and antifolate polyglutamylation to achieve selective anticancer chemotherapy

“…PteGl u-~f-Gl u. glutamylation has been achieved by biochemical modulation and by structural changes specific to individual antifolates; each of these strategies has distinct disadvantages in addition to their advantages (reviewed in [26]). We have proposed that a generic structural change that enhances polyglutamylation of any folate/antifolate would be a more successful strategy [26]. For reasons described earlier, our search for a generic means of enhancing polyglutamylation focused on Glu analogs.…”

“…These data suggested that substitution of/3,/3-F2Glu for Glu would increase the efficiency of polyglutamylation of any folate/antifolate. This hypothesis was tested by preparing and characterizing analogs of MTX and folic acid containing fl,/3-F2Glu [20,26]. Both fl,fl-F2MTX (5) and/3,fl-PteF2Glu (6) were more efficient substrates for purified human FPGS than their respective protio congeners (Table 1).…”

“…Since both a 2,4-diamino antifolate (i.e., 5) and a natural folate (i.e., 6) showed increased FPGS substrate effi- ciency, substitution of fl,fl-F2Glu for Glu appears to be a generic means of enhancing polyglutamylation. However, extensive analysis of the FPGS reaction products and of the biological properties of 5 revealed an unusual property of this substitution [26]. Although addition of the first 7-Glu moiety to fl,flF2Glu-substituted folates/antifolates is highly efficient (Table 1), the reaction essentially stops after one addition.…”

Synthesis and Biological Activity of Folic Acid and Methotrexate Analogues Containing l-threo-(2S,4S)-4-Fluoroglutamic Acid and dl-3,3-Difluoroglutamic Acid

“…1,2 Previous publications from our laboratories have documented the use of fluorinated glutamic acids 3,4 and the corresponding fluoroglutamatecontaining analogues of MTX 5,6 as informative probes to investigate the polyglutamylation process. 1,2 Previous publications from our laboratories have documented the use of fluorinated glutamic acids 3,4 and the corresponding fluoroglutamatecontaining analogues of MTX 5,6 as informative probes to investigate the polyglutamylation process.…”

“…1,2 Previous publications from our laboratories have documented the use of fluorinated glutamic acids 3,4 and the corresponding fluoroglutamatecontaining analogues of MTX 5,6 as informative probes to investigate the polyglutamylation process. 6,9 The well-documented effects of the reduced folate, 5-formyltetrahydrofolic acid (leucovorin) in the rescue of cells treated with "high-dose" MTX chemotherapy 10 and the potentiation of 5-fluorouracil cytotoxicity 11 suggests that fluoroglutamate-containing analogues of folic acid and leucovorin might serve as useful probes of the role of polyglutamylation in folic acid and/or leucovorin biochemistry and pharmacology in intact mammalian cells. 6,9 The well-documented effects of the reduced folate, 5-formyltetrahydrofolic acid (leucovorin) in the rescue of cells treated with "high-dose" MTX chemotherapy 10 and the potentiation of 5-fluorouracil cytotoxicity 11 suggests that fluoroglutamate-containing analogues of folic acid and leucovorin might serve as useful probes of the role of polyglutamylation in folic acid and/or leucovorin biochemistry and pharmacology in intact mammalian cells.…”