Irinotecan (CPT-11), a derivative of camptothecin, is an inhibitor of DNA topoisomerase I (Topo I). Irinotecan has antitumor activity by preventing DNA strand reattachment through binding to the Topo I complex, resulting in double-stranded DNA breaks and cell death.

方法：人乳腺癌细胞 MCF-7 用 Irinotecan (10-320 µg/mL) 处理 24-48 h，使用 trypan blue 检测细胞活力。
结果：Irinotecan 处理 24 h，10 µg/mL 时细胞活力降至 85.5%，160 µg/mL 时活力降至 58%。Irinotecan 处理 48 h，160 µg/mL 时活力降至 33%。[1]
方法：HCT116 p53+/+,hMLH1+、p53+/+,hMLH1- 和 p53-/-,hMLH1- 用 Irinotecan (4.5 µM) 处理 48 h，使用 Flow Cytometry 分析细胞周期情况。
结果：Irinotecan 处理在所有三种细胞系中诱导不同持续时间的 G2/M 停滞。在 p53+/+、hMLH1+ 细胞系中维持阻滞至少 12 天。在治疗开始后的 6-9 天内，p53+/+、hMLH1- 细胞系中的阻滞缓慢释放，表明 hMLH1 分子的状态可能间接或直接影响 G2/M 阻滞的维持。在 p53-/- 细胞系中，G2/M 阻滞在治疗开始后 4 天内就已经终止。[2]

方法：为检测体内抗肿瘤活性，将 Irinotecan (40 mg/kg) 腹腔注射给 MLL 重排 ALL 异种移植物的 NSG 小鼠模型，每周三次，持续四周。
结果：Irinotecan 在体内有效抑制 MLL 重排 ALL 的体内生长。[3]
方法：为检测体内抗肿瘤活性，将 Irinotecan (10 mg/kg 每四天一次，给药四次；或 40 mg/kg 每四天一次，给药六次) 腹腔注射给携带五种 CRC 异种移植瘤的 swiss nu/nu 小鼠。
结果：在低剂量 Irinotecan 下，五个异种移植物中的四个对 Irinotecan 有反应，生长延迟长达 10 天。在高剂量 Irinotecan 下，五个异种移植物显示出可变但显著的反应。[4]

Irinotecan is dissolved in DMSO and stored, and then diluted with appropriate medium before use[1]. To determine the effects of Irinotecan in combination with 5-FU, the MTT assay is used. Depending on the cell lines, 10,000 to 20,000 cells per well are seeded in 96-well plates and incubated for 24 h in complete medium. On day 2, cells are incubated in the absence or presence of Irinotecan for 30 min followed by 5-FU for 24 h. After another 24 h in complete medium without any additives, MTT reagent is added on day 4 to initiate the assay and the cells are incubated for an additional 4 h at 37°C. After removal of the medium and dissolving the crystals with acidified isopropanol, the samples are analyzed using an ELISA plate reader at 570 nm. The value at 650 nm is subtracted as background[1].