Analysis of gene expression change in cancer cells induced by nucleolar stress

Accumulating evidence indicate that aberrantly increased ribosome biogenesis is a hallmark of cancer. As such, there is a growing interest in the development of strategies to target this pathway for cancer therapeutic. It is well established that inhibition of any steps of ribosome biogenesis induces a nucleolar stress characterized by p53 activation and subsequent cell cycle arrest and/or cell death. However, cells derived from solid tumors have demonstrated different degree of sensitivity to ribosome biogenesis inhibition, where cytostatic effects rather than apoptosis are more often observed. The reason for this is not clear and the p53-specific transcriptional program induced after nucleolar stress has not been previously investigated. To investigate changes in gene expression induced by nucleolar stress we performed gene expression analysis comparing RNA from HCT116 (p53 WT) cells treated with control (duplicate experiment) vs. Las1L siRNAs (two different siRNAs). HCT116 cells were treated with control siRNA (in duplicate), Las1L siRNA #1 or Las1L siRNA #2 for 72 hours. Total RNAs, extracted with Trizol reagent (Invitrogen), were amplified, labeled, and hybridized to an Illumina HumanHT-12 v4 expression bead chip kit using standard protocols at The Microarray Core Lab, UT McGovern Medical School. All analyses were performed using GenomeStudio software (Illumina, Inc.).