Research Area: Immunology Biological Activity: Abitrexate(Methotrexate) is an antimetabolite and antifolate agent with antineoplastic and immunosuppressant activities. Methotrexate competitively and irreversibly inhibits dihydrofolate reductase (DHFR), resulting in inhibition of purine nucleotide and thymidylate synthesis and, subsequently, inhibition of DNA and RNA syntheses. Methotrexate also exhibits potent immunosuppressant activity although the mechanism(s) of actions is unclear. [1,2] In a panel of six pediatric leukemia and lymphoma cell lines, this drug performed growth inhibitory activity with median IC50 78 nM. [3] |