Glucocorticoid transcriptome in S49 lymphoid cells expressing Bcl2

S49 (Neo) cells die by apoptosis following dexamethasone (dex) treatment whereas S49 cells expressing Bcl2 are resistant to glucocorticoid-induced cell death. Provocatively, mimicking the loss of intracellular potassium using a low dose of a microbial toxin that acts as a potassium ionophore in combination with dex overcame the resistance afforded by Bcl2 and killed the cells. The ability of the microbial toxin to trigger apoptosis of S49 (Bcl2) cells depends critically on the duration of dex treatment, as a 48-hour dex treatment sensitized the cells to die whereas a 24-hour exposure did not. To determine how the glucocorticoid signaling profile differs at these two time points, we performed RNAseq on RNA isolated from S49 (Neo) cells and S49 (Bcl2) cells treated with and without dex for 24 and 48 hours. Overall design: S49 (Neo) are S49.1 mouse lymphoma cells stably transfected with a recombinant amphitropic retrovirus carrying a G418 (Neomycin) antibiotic resistance gene (Cancer Res 1992; 52: 5407-5411), and S49 (Bcl2) cells were additionally transfected with the Bcl2 proto-oncogene (Cancer Res 1992; 52: 5407-5411). S49 (Neo) cells and S49 (Bcl2) cells were treated with and without dexamethasone for 24 or 48 hours. Total RNA was extracted and purified from cells using a QIAGEN RNeasy RNA isolation kit according to the manufacturer's protocol. RNA-seq libraries were generated with 1 mg of RNA as input using the TruSeq RNA Sample Prep Kit (Illumina, San Diego, CA) and poly(A)-enriched according to the TruSeq protocol. Indexed samples were sequenced using the 75-bp paired-end protocol via the NextSeq500 (Illumina) according to the manufacturer's protocol.