In the course of drug development, analysis of cellular efficacy represents a critical stage before drugs proceed into in vivo studies. For anti-cancer drugs, one method of choice is to assess the drug's impact on tumor cell proliferation. Usually proliferation is analysed in 2D format, analysing cell growth on a flat surface. However, accumulating data suggest that cells behave in a more physiological manner when growing in a 3D matrix. In fact, the gold standard for analysing the transformed status of cells is growth in soft agar, a semi-solid medium in which epithelial cells grow in 3D due to their transformation-related anchorage-independent status. In order to allow a more physiological cellular drug screening for proliferation as well as for transformation, we have now established soft agar assays in 96 well format for 60 tumor cell lines derived from solid tumors. Our data show the multitude of outcomes that may be expected from such a comprehensive study, e.g. we present IC50 analyses indicating that the same compound can have seemingly contradictory, i.e. stimulatory as well as inhibitory activity on soft agar growth, depending on concentration and tested cell line. We propose screening of compounds for impact on cellular soft agar growth as a mandatory prerequisite before testing a drug in vivo.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5681. doi:1538-7445.AM2012-5681