Department of Biomedical Sciences, College of Medicine, The Catholic University of Korea, 505 Banpo-dong, Seocho-ku, Seoul, 137-701, South Korea.
Arch Pharm Res. 2013 May;36(5):634-40. doi: 10.1007/s12272-013-0061-2. Epub 2013 Mar 28.
Multicellular layers (MCL) of cancer cells is an in vitro 3-dimensional (3D) model that mimics avascular microregions of human solid tumors and has been shown to be useful in pharmacokinetic-pharmacodynamic studies of anticancer agents. We investigated whether Ki-67, which is widely used as a proliferation marker, can be used to evaluate changes in proliferative fractions following drug exposure in MCL of HT-29 human colorectal cancer cells. Ki-67 expression was monitored and compared between cancer cells cultured as monolayers or MCL. Drug distribution and Ki-67 expression were evaluated within MCL following exposure to doxorubicin and paclitaxel. Ki-67 expression was observed in the nuclei of proliferating cells in monolayers, tumor xenograft, and multicellular spheroids. In MCL, however, Ki-67 expression was detected in the membrane/cytoplasm as well as in the nucleus throughout MCL. Neither the location nor the level of expression changed following drug exposure, whereas drug-induced apoptosis increased. Our data show that membranous/cytoplasmic Ki-67 may not be valid as a marker for the proliferative activity of cells grown as MCL. Studies for non-nuclear localization and its mechanism in 3D in vitro models of other cell lines are warranted.
多细胞层（MCL）的癌细胞是一种体外 3 维（3D）模型，模拟了人类实体肿瘤的无血管微区，已被证明在抗癌药物的药代动力学-药效学研究中非常有用。我们研究了 Ki-67 是否可以作为增殖标志物，用于评估 HT-29 人结直肠癌细胞 MCL 中药物暴露后增殖分数的变化。监测并比较了单层或 MCL 培养的癌细胞中的 Ki-67 表达。评估了多柔比星和紫杉醇暴露后 MCL 内的药物分布和 Ki-67 表达。Ki-67 在单层培养的增殖细胞、肿瘤异种移植物和多细胞球体的细胞核中观察到。然而，在 MCL 中，Ki-67 表达在整个 MCL 的膜/细胞质以及细胞核中均有检测到。药物暴露后，Ki-67 的位置和表达水平均未发生变化，而药物诱导的细胞凋亡增加。我们的数据表明，作为 MCL 生长细胞增殖活性的标志物，膜/细胞质 Ki-67 可能并不有效。有必要对其他细胞系的 3D 体外模型中的非核定位及其机制进行研究。
