Knockdown of core binding factorβ alters sphingolipid metabolism
Abstract
Core binding factor (CBF) is a heterodimeric transcription factor containing one of three DNA‐binding proteins of the Runt‐related transcription factor family (RUNX1–3) and the non‐DNA‐binding protein, CBFβ. RUNX1 and CBFβ are the most common targets of chromosomal rearrangements in leukemia. CBF has been implicated in other cancer types; for example RUNX1 and RUNX2 are implicated in cancers of epithelial origin, including prostate, breast, and ovarian cancers. In these tumors, CBF is involved in maintaining the malignant phenotype and, when highly over‐expressed, contributes to metastatic growth in bone. Herein, lentiviral delivery of CBFβ‐specific shRNAs was used to achieve a 95% reduction of CBFβ in an ovarian cancer cell line. This drastic reduction in CBFβ expression resulted in growth inhibition that was not associated with a cell cycle block or an increase in apoptosis. However, CBFβ silencing resulted in increased autophagy and production of reactive oxygen species (ROS). Since sphingolipid and ceramide metabolism regulates non‐apoptotic cell death, autophagy, and ROS production, fumonsin B1 (FB1), an inhibitor of ceramide synthase, was used to alter ceramide production in the CBFβ‐silenced cells. FB1 treatment inhibited the CBFβ‐dependent increase in autophagy and provided a modest increase in cell survival. To document alterations to sphingolipids in the CBFβ‐silenced cells, ceramide, and lactosylceramide levels were directly examined by mass spectrometry. Substantial increases in ceramide species and decreases in lactosylceramides were identified. Altogether, this report provides evidence that CBF transcriptional pathways control cellular survival, at least in part, through sphingolipid metabolism. J. Cell. Physiol. 228: 2350–2364, 2013. © 2013 Wiley Periodicals, Inc.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Aug 23, 2013
- Source ID
- 10.1002/jcp.24406
Entities
People
- Adam H. Greer
- Floyd Galiano
- J. Nathan Davis
- James Cardelli
- Katie Fennell
- Marcie Fowler
- Ross S. Berkowitz
- Shari Meyers
- Shu‐wing Ng
- Thomas Yong
- Yara W. Moustafa
Organizations
- Harvard Medical School
- LSU Health Sciences Center New Orleans
- Quinnipiac University
- United States Army Institute of Surgical Research
- United States Department of Defense