Figure 4: Transgenic LDR cells used in a low-throughput drug screen. (a) Highly responsive cells chosen for the assay were expanded clonally, showing 70%–90% response to 25 mM butyrate (right), as compared to vehicle treated cells (left). (b) A 96-well plate used to screen compounds from the NCI structural diversity library was visualized after treatment with 4 μM compounds in DMSO, using a Discovery 1 fluorescent microscope platform and processed on the fly for visualization per well. Hits are easily detectable by marked increase in fluorescence. Parental untransfected mouse mammary adenocarcinoma cells were used to counter screen.