Abstract
Understanding the regulatory programs enabling cancer stem cells (CSCs) to self-renew and drive tumorigenicity could identify new treatments. Through comparative chromatin-state and gene expression analyses in ovarian CSCs versus non-CSCs, we identified FOXK2 as a highly expressed stemness-specific transcription factor in ovarian cancer. Its genetic depletion diminished stemness features and reduced tumor initiation capacity. Our mechanistic studies highlight that FOXK2 directly regulated IRE1α (encoded by ERN1) expression, a key sensor for the unfolded protein response (UPR). Chromatin immunoprecipitation and sequencing revealed that FOXK2 bound to an intronic regulatory element of ERN1. Blocking FOXK2 from binding to this enhancer by using a catalytically inactive CRISPR/Cas9 (dCas9) diminished IRE1α transcription. At the molecular level, FOXK2-driven upregulation of IRE1α led to alternative XBP1 splicing and activation of stemness pathways, while genetic or pharmacological blockade of this sensor of the UPR inhibited ovarian CSCs. Collectively, these data establish what we believe is a new function for FOXK2 as a key transcriptional regulator of CSCs and a mediator of the UPR, providing insight into potentially targetable new pathways in CSCs.
| Original language | English (US) |
|---|---|
| Article number | e151591 |
| Journal | Journal of Clinical Investigation |
| Volume | 132 |
| Issue number | 10 |
| DOIs | |
| State | Published - May 16 2022 |
Funding
We thank Horacio Cardenas for helpful edits and Debabrata Chakravarti for insightful comments. This research was supported by funding from the US Department of Veterans Affairs (BX000792-09A2), the Diana Princess of Wales endowed Professorship from the Robert H. Lurie Comprehensive Cancer Center to DM, and NCI U54 CA268084-02 (to DM and MA). Tumor specimens were procured through the Tissue Pathology Core and sequencing was performed in the NUSeq Core supported by NCI CCSG P30 CA060553 awarded to the Robert H. Lurie Comprehensive Cancer Center. Flow cytometry analyses were performed in the Northwestern University Flow Cytometry Core Facility supported by Cancer Center grant NCI CA060553. Imaging of TMAs was performed in the Center for Advanced Microscopy/Nikon Imaging Center (CAM) at Northwestern University supported by NCI grant CA060553. This research was supported in part through the computational resources and staff contributions provided for the Quest high-performance computing facility at Northwestern University, which is jointly supported by the Office of the Provost, the Office for Research, and Northwestern University Information Technology.
ASJC Scopus subject areas
- General Medicine
