Gamendazole Inhibits ADPKD Cell Proliferation and Induces Cytoskeletal Rearrangements

University of Kansas
posted on 08/25/2009

• request more info 
•   
•  LICENSE ONLINE

Inhibition of Hsp90 chaparone activity has shown great potential in anticancer therapeutics. Hsp90 inhibition causes proteasomal degradation of client proteins, including signaling kinases and cell surface receptors, leading to decreased cell proliferation. We have examined the novel Hsp90 inhibitor gamendazole (GMZ) to determine if it has antiproliferative effects on primary human ADPKD cyst epithelial cells. GMZ, a lonidamine-derived indazole carboxylate compound, is well-tolerated in animal studies. In this study, MTT assays showed that GMZ significantly inhibited both cAMP- and EGF-induced proliferation of ADPKD cells in a dose-dependent manner (1 M 25 M GMZ for 72h). This was verified by DAPI staining to count dividing cells, which showed that GMZ treatment (50 M for 16h) decreased the mitotic index in comparison to untreated controls (2.6% vs. 4.1%, P<0.05), and that 100 M GMZ was even more effective (1.7% vs. 4.1%, P<0.01). Western blotting of GMZ-treated ADPKD cells (50 M for 48h) showed decreased P-ERK levels (71.2% of controls; n = 2), while total ERK levels were unchanged; and decreased levels of the Hsp90 client proteins ErbB2 and Cdk4. To determine if GMZ treatment alters actin cytoskeleton dynamics, ADPKD cells were stained with phalloidin and examined by fluorescence microscopy. GMZ-treated cultures had a higher proportion of smaller cells with fewer and smaller lamellipodia and decreased cytoplasmic actin staining. Wound-healing scratch assays showed that GMZ-treated ADPKD cells were unable to accomplish wound closure even at low GMZ concentration (10 M), consistent with an alteration in the actin cytoskeleton and effects on cell motility. Thus, GMZ treatment decreases ADPKD cell proliferation and motility and as such may slow cyst formation. These properties, along with its low toxicity, make GMZ an attractive candidate for treatment of ADPKD. KU is willing to enter into a Confidential Disclosure Agreement for the purpose of negotiating a License Agreement. If you are interested in learning details of this invention, please contact: James G. Baxendale Executive Director, Technology Transfer & Intellectual Property at: jbaxendale@ku.edu Or Christopher Zien, Ph.D. Licensing Associate, Technology Transfer & Intellectual Property at: czien@ku.edu Updated: October 20, 2008