Three-Dimensional (3D) Cell Cultures in Cell-based Assays for in-vitro Evaluation of Anticancer Drugs

Abstract

This study systematically investigated the cell proliferation rates, spheroid structures, cellular responses to different anti-cancer drugs, the expression of drug action-related proteins, and the possible correlations among these properties of 3D spheroids on Matrigel in comparison to 2D monolayer cells, using two cancer cell lines-the prostate cancer cell line, DU145, and the oral cancer cell line, CAL27. Compared to the traditional 2D-cultured cells, 3D-cultured CAL27 cells had enhanced proliferation by approximately 50-70% at various seeding cell densities, whereas 3D-cultured DU145 cells showed reduced proliferation at all tested seeding cell densities by 20-40%. In drug tests, the sensitivity of 3D-cultured DU145 cells relative to 2D-cultured cells showed an obvious drug action mechanism dependency in response to three anticancer drugs, Rapamycin, Docetaxel, and Camptothecin, whereas 3D-cultured CAL27 cells responded more sensitively than 2D-cultured cells to all three tested drugs, Docetaxel, Bleomycin, and Erlotinib, indicating the relative proliferation rate between 3D and 2D cultured cells may be a dominating factor in this case and mitigated the factor of drug action mechanism. The elevated expression of EGFR in 3D-cultured CAL27 was correlated with its more sensitive response to Erlotinib (acting through binding to EGRF) compared to 2D-cultured cells; Similarly, the expression of βIII tubulin in 3D-cultured DU145 cells was found to be increased and correlated with their higher resistance to Doxetaxel compared to 2D-cultured cells.