Analysis of sensitivity and cell death pathways mediated by anti-cancer drugs using three-dimensional culture system

Objective: The aim of this study was to evaluate the differences of cytotoxicity mediated by anti-cancer drugs between 2D and 3D culture conditions. Methodology: The colon cancer cell line HCT116 was cultured in 2D and 3D conditions. Anti-proliferation effects and cell death pathways of cytotoxic agents, i.e., SN-38 and multi-kinase inhibitors i.e., sorafenib were examined. Data was analyzed by Studentʼs t-test. Results: Although SN-38 induced significant apoptosis associated with caspase-3/7 activation in 2D condition, apoptosis and anti-proliferation effects of SN-38 dramatically diminished in 3D condition. In contrast, anti-proliferation effects mediated by sorafenib unchanged. Interestingly, sorafenib induced significant apoptosis in the cells locating in the center of the 3D spheroids, whereas it did not induce caspase activation in 2D condition. In addition, 2D culture with low glucose concentration, a model mimicking central condition of the spheroids, revealed the significant cell death with caspase activation by sorafenib. Conclusion: 3D culture system provide new findings regarding cytotoxicity of compounds which are not identified by the 2D culture.