The natural product withaferin A (WFA) exhibits antitumor and antiangiogenesis activity in vivo, which results from this drug's potent growth inhibitory activities. Here, we show that WFA binds to the intermediate filament (IF) protein, vimentin, by covalently modifying its cysteine residue, which is present in the highly conserved α-helical coiled coil 2B domain. WFA induces vimentin filaments to aggregate in vitro, an activity manifested in vivo as punctate cytoplasmic aggregates that colocalize vimentin and F-actin. WFA's potent dominant-negative effect on F-actin requires vimentin expression and induces apoptosis. Finally, we show that WFA-induced inhibition of capillary growth in a mouse model of corneal neovascularization is compromised in vimentin-deficient mice. These findings identify WFA as a chemical genetic probe of IF functions, and illuminate a potential molecular target for withanolide-based therapeutics for treating angioproliferative and malignant diseases.
|Number of pages||12|
|Journal||Chemistry and Biology|
|State||Published - Jun 25 2007|
Bibliographical noteFunding Information:
We thank Jack Goodman from the UK Mass Spectrometry Core Facility, Greg Bauman and Jennifer Strange from Flow Cytometry Core Facility, and Mary Engle from Imaging and Histology Core Center for their expert technical assistance, and J. Ambati and A. Pearson for scientific discussions. R.M. is supported by a Fight for Sight Foundation grant-in-aid, Kentucky Science and Engineering Foundation award, and a Research to Prevent Blindness Challenge Award to the Department of Ophthalmology; C.-G.Z. by NIDA/NIH; K.B.K. by the Kentucky Lung Cancer Research Program; D.M.M is the recipient of a Burroughs Wellcome Fund Clinical Scientist Award in Translational Research, and is supported by the Arthritis Foundation and NHLB/NIH and NIAID/NIH. The authors declare no conflicts of interest.
ASJC Scopus subject areas
- Molecular Medicine
- Molecular Biology
- Drug Discovery
- Clinical Biochemistry