1843u89 and Leukemia

1843u89 has been researched along with Leukemia* in 1 studies

Other Studies

1 other study(ies) available for 1843u89 and Leukemia

Article	Year
Clustering of mutations in the first transmembrane domain of the human reduced folate carrier in GW1843U89-resistant leukemia cells with impaired antifolate transport and augmented folate uptake. The Journal of biological chemistry, 2000, Oct-06, Volume: 275, Issue:40 We have studied the molecular basis for the resistance of human CEM leukemia cells to GW1843, a thymidylate synthase inhibitor. GW1843-resistant cells displayed a approximately 100-fold resistance to GW1843 and methotrexate but were collaterally sensitive to the lipophilic antifolates trimetrexate and AG337, which enter cells by diffusion. These cells exhibited a 12-fold decreased methotrexate influx but surprisingly had a 2-fold decreased folic acid growth requirement. This was associated with a 4-fold increased influx of folic acid, a 3.5-fold increased steady-state level of folic acid, and a 2.3-fold expansion of the cellular folate pool. Characterization of the transport kinetic properties revealed that GW1843-resistant cells had the following alterations: (a) 11-fold decreased transport K(m) for folic acid; (b) 6-fold increased transport K(m) for GW1843; and (c) a slightly increased transport V(max) for folic acid. Sequence analysis showed that GW1843-resistant cells contained the mutations Val-29 --> Leu, Glu-45 --> Lys, and Ser-46 --> Ile in the first transmembrane domain of the reduced folate carrier. Transfection of the mutant-reduced folate carrier cDNA into methotrexate transport null cells conferred resistance to GW1843. This is the first demonstration of multiple mutations in a confined region of the human reduced folate carrier in an antifolate-resistant mutant. We conclude that certain amino acid residues in the first transmembrane domain play a key role in (anti)folate binding and in the conferring of drug resistance. Topics: Antimetabolites, Antineoplastic; Biological Transport; Blotting, Northern; Blotting, Southern; Blotting, Western; Carrier Proteins; Cell Division; Cell Membrane; Chlorides; DNA Mutational Analysis; DNA, Complementary; Dose-Response Relationship, Drug; Drug Resistance, Neoplasm; Enzyme Inhibitors; Exons; Folic Acid; Folic Acid Antagonists; Humans; Indoles; Inhibitory Concentration 50; Isoindoles; Kinetics; Leucovorin; Leukemia; Membrane Proteins; Membrane Transport Proteins; Methotrexate; Mutagenesis, Site-Directed; Mutation; Polymorphism, Single-Stranded Conformational; Protein Structure, Secondary; Protein Structure, Tertiary; Quinazolines; Recombinant Proteins; Reduced Folate Carrier Protein; Thymidylate Synthase; Time Factors; Transfection; Trimetrexate; Tumor Cells, Cultured	2000

Article

Year

Clustering of mutations in the first transmembrane domain of the human reduced folate carrier in GW1843U89-resistant leukemia cells with impaired antifolate transport and augmented folate uptake.

The Journal of biological chemistry, 2000, Oct-06, Volume: 275, Issue:40

We have studied the molecular basis for the resistance of human CEM leukemia cells to GW1843, a thymidylate synthase inhibitor. GW1843-resistant cells displayed a approximately 100-fold resistance to GW1843 and methotrexate but were collaterally sensitive to the lipophilic antifolates trimetrexate and AG337, which enter cells by diffusion. These cells exhibited a 12-fold decreased methotrexate influx but surprisingly had a 2-fold decreased folic acid growth requirement. This was associated with a 4-fold increased influx of folic acid, a 3.5-fold increased steady-state level of folic acid, and a 2.3-fold expansion of the cellular folate pool. Characterization of the transport kinetic properties revealed that GW1843-resistant cells had the following alterations: (a) 11-fold decreased transport K(m) for folic acid; (b) 6-fold increased transport K(m) for GW1843; and (c) a slightly increased transport V(max) for folic acid. Sequence analysis showed that GW1843-resistant cells contained the mutations Val-29 --> Leu, Glu-45 --> Lys, and Ser-46 --> Ile in the first transmembrane domain of the reduced folate carrier. Transfection of the mutant-reduced folate carrier cDNA into methotrexate transport null cells conferred resistance to GW1843. This is the first demonstration of multiple mutations in a confined region of the human reduced folate carrier in an antifolate-resistant mutant. We conclude that certain amino acid residues in the first transmembrane domain play a key role in (anti)folate binding and in the conferring of drug resistance.

Topics: Antimetabolites, Antineoplastic; Biological Transport; Blotting, Northern; Blotting, Southern; Blotting, Western; Carrier Proteins; Cell Division; Cell Membrane; Chlorides; DNA Mutational Analysis; DNA, Complementary; Dose-Response Relationship, Drug; Drug Resistance, Neoplasm; Enzyme Inhibitors; Exons; Folic Acid; Folic Acid Antagonists; Humans; Indoles; Inhibitory Concentration 50; Isoindoles; Kinetics; Leucovorin; Leukemia; Membrane Proteins; Membrane Transport Proteins; Methotrexate; Mutagenesis, Site-Directed; Mutation; Polymorphism, Single-Stranded Conformational; Protein Structure, Secondary; Protein Structure, Tertiary; Quinazolines; Recombinant Proteins; Reduced Folate Carrier Protein; Thymidylate Synthase; Time Factors; Transfection; Trimetrexate; Tumor Cells, Cultured

2000