CytarabineS1648

Cytarabine (AraC) is phosphorylated into a triphosphate form (Ara-CTP) involving deoxycytidine kinase (dCK), which competes with dCTP for incorporation into DNA, and then blocks DNA synthesis by inhibiting the function of DNA and RNA polymerases. Cytarabine displays a higher growth inhibitory activity towards wild-type CCRF-CEM cells compared to other acute myelogenous leukemia (AML) cells with IC50 of 16 nM. ^[1] Increasing concentrations of Cytarabine (IC50 of 0.69 μM) results in decreased metabolic activity of sensitive rat leukemic cell line RO/1, and the cell toxity can be highly enhanced by transfection with human wt dCK (IC50 of 0.037 μM) but not the inactive, alternatively spliced dCK forms. ^[2] Cytarabine apparently induces apoptosis of rat sympathetic neurons at 10 μM, of which 100 μM shows the highest toxicity and kills over 80% of the neurons by 84 hours, involving the release of mitochondrial cytochrome-c and the activation of caspase-3, and the toxicity can be attenuated by p53 knockdown and delayed by bax deletion. ^[3]