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Exp Cell Res. 2015 Feb 1;331(1):58-72. doi: 10.1016/j.yexcr.2014.09.034. Epub 2014 Oct 7.

Withaferin A disrupts ubiquitin-based NEMO reorganization induced by canonical NF-κB signaling.

Author information

1
McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin-Madison, 6159 Wisconsin Institute for Medical Research, 1111 Highland Avenue, Madison, WI 53705, USA; Medical Scientist Training Program, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, WI 53705, USA; Cellular and Molecular Biology Program, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, WI 53705, USA.
2
McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin-Madison, 6159 Wisconsin Institute for Medical Research, 1111 Highland Avenue, Madison, WI 53705, USA.
3
McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin-Madison, 6159 Wisconsin Institute for Medical Research, 1111 Highland Avenue, Madison, WI 53705, USA; Cellular and Molecular Biology Program, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, WI 53705, USA.
4
Department of Medicine, Division of Hematology and Oncology, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, WI 53705, USA.
5
McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin-Madison, 6159 Wisconsin Institute for Medical Research, 1111 Highland Avenue, Madison, WI 53705, USA; Medical Scientist Training Program, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, WI 53705, USA; Molecular and Cellular Pharmacology Program, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, WI 53705, USA.
6
McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin-Madison, 6159 Wisconsin Institute for Medical Research, 1111 Highland Avenue, Madison, WI 53705, USA; Medical Scientist Training Program, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, WI 53705, USA; Cellular and Molecular Biology Program, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, WI 53705, USA. Electronic address: smiyamot@wisc.edu.

Abstract

The NF-κB family of transcription factors regulates numerous cellular processes, including cell proliferation and survival responses. The constitutive activation of NF-κB has also emerged as an important oncogenic driver in many malignancies, such as activated B-cell like diffuse large B cell lymphoma, among others. In this study, we investigated the impact and mechanisms of action of Withaferin A, a naturally produced steroidal lactone, against both signal-inducible as well as constitutive NF-κB activities. We found that Withaferin A is a robust inhibitor of canonical and constitutive NF-κB activities, leading to apoptosis of certain lymphoma lines. In the canonical pathway induced by TNF, Withaferin A did not disrupt RIP1 polyubiquitination or NEMO-IKKβ interaction and was a poor direct IKKβ inhibitor, but prevented the formation of TNF-induced NEMO foci which colocalized with TNF ligand. While GFP-NEMO efficiently formed TNF-induced foci, a GFP-NEMO(Y308S) mutant that is defective in binding to polyubiquitin chains did not form foci. Our study reveals that Withaferin A is a novel type of IKK inhibitor which acts by disrupting NEMO reorganization into ubiquitin-based signaling structures in vivo.

KEYWORDS:

ABC type diffuse large B-cell lymphoma; Apoptosis; IKK; NEMO; NEMO foci; NF-κB; Ubiquitin; Withaferin A

PMID:
25304104
PMCID:
PMC4302062
DOI:
10.1016/j.yexcr.2014.09.034
[Indexed for MEDLINE]
Free PMC Article

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