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Updated: Oct 9, 2026
Identification of Transcription Factor Regulators using Medium-Throughput Screening of Arrayed Libraries and a Dual-Luciferase-Based Reporter
Published on: March 27, 2020
Assessment of tumor necrosis factor receptor and Fas signaling pathways by transcriptional profiling
1Division of Molecular Pharmacology, Huntsman Cancer Institute, University of Utah, Salt Lake City 84112, USA.
Abstract:
Apoptosis, or programmed cell death, is an important mechanism by which cells are eliminated during immune regulation and embryonic development. Aberrations in the signaling pathways leading to apoptosis may result in cancer, autoimmune diseases, or inflammatory disorders. In view of this, an understanding of the signaling capabilities of apoptosis-inducing or death receptors is essential to understanding their roles in biology and disease. We used cDNA microarrays to examine the downstream transcriptional effects of two members of the tumor necrosis factor (TNF) family of death receptor ligands. We compared the transcriptional responses of a model colon cancer cell line, HT29, to TNF-alpha and anti-Fas activating antibody. Both ligands induced a subset of genes characteristic of activation of the transcription factor nuclear factor-kappaB (NF-kappaB). Follow-up analyses demonstrated that, although TNF-alpha activated NF-kappaB through IkappaB-alpha degradation, alpha-Fas treatment led to NF-kappaB activation through a mechanism distinct from IkappaB-alpha degradation.
Insights
Programmed cell death (apoptosis) is vital for development and immunity. This study reveals distinct NF-kappaB activation pathways for TNF-alpha and anti-Fas, crucial for understanding diseases like cancer.
Area of Science:
- Cell Biology
- Molecular Biology
- Immunology
Background:
- Apoptosis, or programmed cell death, is critical for normal biological processes, including immune regulation and embryonic development.
- Dysregulation of apoptosis signaling pathways is implicated in various diseases such as cancer, autoimmune disorders, and inflammatory conditions.
- Understanding the signaling mechanisms of death receptors is essential for elucidating their roles in health and disease.
Purpose of the Study:
- To investigate the downstream transcriptional effects of two tumor necrosis factor (TNF) family death receptor ligands.
- To compare the transcriptional responses induced by TNF-alpha and anti-Fas activating antibody in a colon cancer cell line.
- To elucidate the specific signaling pathways, particularly nuclear factor-kappaB (NF-kappaB) activation, utilized by these ligands.
Main Methods:
- Utilized cDNA microarrays to analyze gene expression changes.
- Compared the transcriptional profiles of HT29 colon cancer cells treated with TNF-alpha and anti-Fas.
- Performed follow-up analyses to investigate the mechanisms of NF-kappaB activation.
Main Results:
- Both TNF-alpha and anti-Fas treatments induced a common set of genes associated with nuclear factor-kappaB (NF-kappaB) activation.
- TNF-alpha activated NF-kappaB via the degradation of IkappaB-alpha.
- Anti-Fas antibody treatment activated NF-kappaB through a pathway independent of IkappaB-alpha degradation.
Conclusions:
- TNF-alpha and anti-Fas signaling pathways converge on NF-kappaB activation but utilize distinct upstream mechanisms.
- The differential activation of NF-kappaB by death receptor ligands has significant implications for understanding cellular responses in development and disease.
- Further research into these distinct pathways could offer novel therapeutic targets for apoptosis-related diseases.
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