Coordination of Fenretinide-Induced Apoptosis by Stress-Responsive Regulators in Leukemia Cells

Pharmacological intervention affecting intracellular redox balance often results in oxidative stress-mediated apoptosis, which also represents a new direction for cancer therapeutic designs. However, mechanistic links between redox signals and their downstream effects on apoptosis have not yet been elucidated in cancer cells. Here, we report a detailed analysis of fenretinide-induced apoptosis in leukemia-derived cells through a systems approach, integrating experimental and computational methods together with advanced data mining tools. Robust transcriptome profiling reveals numerous stress-responsive events at the temporal and spatial levels, including oxidative stress, endoplasmic reticulum stress/unfolded protein response, translational repression, proteasome activation, and apoptosis induction. Moreover, stress-responsive transcription factors, as highlighted by NRF2 and HSF1, play prominent roles in the configuration of these relevant events. Several lines of evidence suggest that these stress-responsive regulators and thus their target genes are involved not only in converting oxidative signaling into downstream effects but also in coordinating the progression of cell apoptosis. This study provides a roadmap for understanding oxidative stress-mediated apoptosis in cancer cells, which may be further developed into more sophisticated therapeutic protocols, as implicated by synergistic induction of cell apoptosis using proteasome inhibitors with fenretinide.