Dihydrofolate reductase mutant with exceptional resistance to methotrexate but not to trimetrexate.
Two double (F31A/F34A, I60A/L67G) and one quadruple (F31A/F34A/I60A/L67G) mutant murine dihydrofolate reductases were constructed and evaluated for their ability to impart antifolate resistance. Both I60A/L67G and F31A/F34A/I60A/L67G were found to be unstable and devoid of catalytic activity. The K(i) values for F31A/F34A, methotrexate (MTX), bis-MTX, and PT-523 were found to be 10100-, 4410-, and 617-fold higher than the wild-type enzyme, respectively, but only 13.5-fold higher for trimetrexate (TMTX). These findings suggest that F31A/F34A could be used for gene therapy to render normal cells resistant to MTX but sensitive to TMTX.
Pineda
Pamela
P
Departments of Medicinal Chemistry and of Genetics and Development, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Kanter
Aaron
A
McIvor
R Scott
RS
Benkovic
Stephen J
SJ
Rosowsky
Andre
A
Wagner
Carston R
CR
D000970:Antineoplastic Agents / Q000138:chemical synthesis* / Q000737:chemistry; D019008:Drug Resistance, Neoplasm; D005493:Folic Acid Antagonists / Q000138:chemical synthesis* / Q000737:chemistry; D007700:Kinetics; D008727:Methotrexate / Q000737:chemistry*; D009154:Mutation; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification; D013762:Tetrahydrofolate Dehydrogenase / Q000737:chemistry* / Q000235:genetics*; D016597:Trimetrexate / Q000737:chemistry*
D000970:Antineoplastic Agents; D005493:Folic Acid Antagonists; D011994:Recombinant Proteins; D013762:Tetrahydrofolate Dehydrogenase; D016597:Trimetrexate; D008727:Methotrexate