Cytarabine (Ara-C) is a nucleoside analog, an inhibitor of DNA synthesis (IC50=16 nM). Cytarabine inhibits DNA polymerase and induces cell cycle arrest, autophagy, and apoptosis. Cytarabine has antitumor activity.

DNA synthesis:16 nM

方法：原代 AML 细胞用 Cytarabine (10-5000 nM) 处理 24 h，使用 MTT 方法检测细胞活力。
结果：Cytarabine 具有剂量依赖性的生长抑制作用，IC50 为1.12 μM。[1]
方法：人组织细胞淋巴瘤细胞 U937 用 Cytarabine (10-1000 nM) 处理 72 h，使用 Flow Cytometry 检测细胞周期情况。
结果：Cytarabine 剂量依赖性地降低了用 10 和 100 nM 处理的细胞中 G1 期的细胞比例，并增加了 S 期的比例。当以最高剂量 1000 nM 施用时，Cytarabine 引起亚 G1 期和 G2/M 期比例的显著增加。[2]

方法：为研究 AML 的化疗耐药性，将 Cytarabine (10-60 mg/kg) 腹腔注射给携带人 AML 肿瘤的 NSG 小鼠，每天一次，持续五天。
结果：在所有接受 60 mg/kg Cytarabine 治疗的小鼠中，在治疗后 2 周出现细胞还原作用，治疗后 4-13 周复发。最低白血病负担和外周血复发时间方面，模型中存在剂量-反应关系。[3]
方法：为检测体内抗肿瘤活性，将 Cytarabine (6.25 mg/kg，每天一次) 和 sorafenib (60 mg/kg，每天两次) 腹腔注射给携带人 AML 肿瘤 U937 的 NOD-SCID-IL2R γnull 小鼠模型，每周一次或持续四十八天。
结果：Cytarabine 与 sorafenib 联合使用在体内产生了强大的抗 AML 活性。[4]

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)