Investigation of the Mechanism of Action by Comprehensive Transcriptome Analysis

To elucidate the SLFN12 RNase effector function, we used whole-genome microarray expression profiling as a discovery platform to identify genes that potentially drive anticancer efficacy upon OPB-171775 treatment. The compound was treated for 8 or 24 hours in control PFSK1 cells and siSLFN12 knockdown PFSK1 cells. Gene set enrichment analysis (GSEA) revealed a significant enrichment of gene sets associated with ribosomal function and the endoplasmic reticulum (ER) stress response in OPB-treated cells compared to control cells. PFSK1 cells were treated with siControl and siSLFN12 for 48 hours. Cells were then treated with OPB-171775 or DMSO control for 8 or 24 hours. Three independent experiments were performed at each time point (8 or 24 hours).