Ganetespib limits ciliation and cystogenesis in autosomal‐dominant polycystic kidney disease (ADPKD)

Abstract

Autosomal-dominant polycystic kidney disease (ADPKD) is associated with progressive formation of renal cysts, kidney enlargement, hypertension, and typically end-stage renal disease. In ADPKD, inherited mutations disrupt function of the polycystins (encoded by PKD1 and PKD2), thus causing loss of a cyst-repressive signal emanating from the renal cilium. Genetic studies have suggested ciliary maintenance is essential for ADPKD pathogenesis. Heat shock protein 90 (HSP90) clients include multiple proteins linked to ciliary maintenance. We determined that ganetespib, a clinical HSP90 inhibitor, inhibited proteasomal repression of NEK8 and the Aurora-A activator trichoplein, rapidly activating Aurora-A kinase and causing ciliary loss in vitro. Using conditional mouse models for ADPKD, we performed long-term (10 or 50 wk) dosing experiments that demonstrated HSP90 inhibition caused durable in vivo loss of cilia, controlled cystic growth, and ameliorated symptoms induced by loss of Pkd1 or Pkd2. Ganetespib efficacy was not increased by combination with 2-deoxy-d-glucose, a glycolysis inhibitor showing some promise for ADPKD. These studies identify a new biologic activity for HSP90 and support a cilia-based mechanism for cyst repression.-Nikonova, A. S., Deneka, A. Y., Kiseleva, A. A., Korobeynikov, V., Gaponova, A., Serebriiskii, I. G., Kopp, M. C., Hensley, H. H., Seeger-Nukpezah, T. N., Somlo, S., Proia, D. A., Golemis, E. A. Ganetespib limits ciliation and cystogenesis in autosomal-dominant polycystic kidney disease (ADPKD).

Tulp3 Is a Ciliary Trafficking Gene that Regulates Polycystic Kidney Disease

“…This led to the hypothesis that in the absence of PC1, a CDCA signal drives cyst formation [15]. Additionally, pharmacological ablation of cilia can ameliorate the cystic phenotype in mouse models of ADPKD [35]. In this study, we found that concomitant Tulp3 deletion ameliorated the Pkd1 cystic phenotype in the adult.…”

Unexpected Activities in Regulating Ciliation Contribute to Off-target Effects of Targeted Drugs

“…Mice were euthanized at 6.5 months of age to collect kidneys and other organs for analysis. MRI analysis, pathologic assessment of cyst formation, and immunofluorescence assessment of cilia in renal cells was performed as described in detail in (29,32).…”

“…Organs from euthanized mice were collected, fixed in 10% phosphate-buffered formaldehyde (formalin), embedded in paraffin, sectioned at 5-mm intervals, and processed for H&E staining or immunofluorescence-based IHC as described in (32). For cilia staining, kidney sections were incubated overnight with primary mAbs against acetylated a-tubulin (sc-23950; Santa Cruz Biotechnology), with further 1-hour incubation with secondary antibodies labeled with Alexa Fluor 488.…”

“…1A and B). On the basis of previously defined activities, as controls we used the Aurora-A kinase (AURKA) inhibitor alisertib as an agent to block ciliary disassembly (22,34), and the HSP90 inhibitor ganetespib as an agent to induce ciliary disassembly (32). Comparison of ciliation pre-and posttreatment using high content microscopy identified 6 kinase inhibitors that caused significant resorption of cilia within 2.5 hours of drug addition, and 5 kinase inhibitors that blocked serum-induced resorption of cilia at the same time point ( Supplementary Table S4).…”

“…In ADPKD, reduction of ciliation in renal cells limits cystogenesis, reducing kidney volume (32,47); conversely, in cancer, loss of cilia has been associated with tumorigenesis (10). We used two models to explore the effect of sunitinib on ciliation in vivo.…”