Cytarabine 是核苷类似物，可引起 S 期细胞周期停滞并抑制DNA聚合酶。它对HSV具有抗病毒作用。它抑制DNA 合成的IC50为16 nM。

Cytarabine is converted to the triphosphate form within the cell and then competes with cytidine for incorporation into DNA. Because the arabinose sugar sterically hinders the rotation of the molecule within DNA, DNA replication ceases, specifically during the S phase of the cell cycle. Cytarabine is an antimetabolite analog of cytidine with a modified sugar moiety (arabinose instead of ribose). This agent also inhibits DNA polymerase, resulting in a decrease in DNA replication and repair.

作用于妊娠Wistar大鼠胎盘时,Cytarabine（250 mg/kg）阻碍胎盘生长,且增加胎盘滋养细胞凋亡,处理3小时后开始增加,6小时达峰,48小时回到处理前水平,且明显增强 p53蛋白及其转录靶点基因,如p21, cyclinG1 ,fas和 caspase-3活性.作用于急性白血病时,Cytarabine引起G1/S期停顿和同步化, 且低剂量可使患白血病Brown Norway大鼠存活时间增加,表明高剂量Cytarabine与抗人类白血病效果无关.

Cytarabine（10 μM） 可诱导大鼠交感神经元凋亡, 100 μM毒性最高,在神经元84 h内可杀死80%神经元（包含线粒体细胞色素-c释放, caspase-3激活）, 通过抑制p53基因可降低毒性,删除bax基因可使毒性延迟产生。Cytarabine可抑制野生型CCRF-CEM 细胞生长活性（IC50：16 nM）,效果远高于其他急性骨髓性白血病。 Cytarabine 浓度依赖性地降低敏感大鼠白血病细胞系RO/1的代谢活性(IC50：0.69 μM) , 且作用于人类野生型脱氧胞啶激酶 (IC50 为 0.037 μM) 时可使细胞毒性增强。

In Vitro Growth Inhibition Assay: Stock solution of Cytarabine is prepared in absolute ethanol, and serial dilutions of Cytarabine are prepared. CCRF-CEM cells are suspended in RPMI medium supplemented with 10% FBS, 0.1% gentamicin, and 1% sodium pyruvate. The cells are suspended in their respective media to give 10 mL volumes of cell suspension at a final density of 3-6 × 104 cells/mL. Appropriate volumes of Cytarabine solution are transferred to the cell suspensions, and incubation is continued for 72 hours. The cells are spun down and resuspended in fresh Cytarabine -free medium, and final cell counts are determined. The data are analyzed by sigmoidal curve fitting of the cell count versus Cytarabine concentration, and the results are expressed as the IC50 (Cytarabine concentration that inhibits cell growth to 50% of the control value).

Cells are incubated in the presence of different concentrations of Cytarabine at 37 °C for 24, 48, and 72 hours. At the time of 20-, 44-, or 68-hour incubation in the presence of Cytarabine, 10 mL of cell proliferation reagent WST-1 solution is added. After 2- and 4-hour incubation with WST-1, cell metabolic activity is assessed with colorimetric changes quantified by measuring the absorbance in a spectrophotometer at 450 nm. And cell division times are calculated from eosin counting in parallel with viability assay(Only for Reference)

147-94-4

C9H13N3O5

243.22

Cytosine β-D-arabinofuranoside;Arabinocytidine;Ara-C;阿糖胞苷;Cytosine Arabinoside

H2O:24.3 mg/mL (100 mM)
DMSO:12.2 mg/mL (50 mM)
Powder: -20°C for 3 years
In solvent: -80°C for 2 years