Withaferin A targets heat shock protein 90 in pancreatic cancer cells

Yanke Yu, Adel Hamza, Tao Zhang, Mancang Gu, Peng Zou, Bryan Newman, Yanyan Li, A. A.Leslie Gunatilaka, Chang Guo Zhan, Duxin Sun

Research output: Contribution to journalArticlepeer-review

206 Scopus citations

Abstract

The purpose of this study is to investigate the efficacy and the mechanism of Hsp90 inhibition of Withaferin A (WA), a steroidal lactone occurring in Withania somnifera, in pancreatic cancer in vitro and in vivo. Withaferin A exhibited potent antiproliferative activity against pancreatic cancer cells in vitro (with IC50s of 1.24, 2.93 and 2.78 μM) in pancreatic cancer cell lines Panc-1, MiaPaCa2 and BxPc3, respectively. Annexin V staining showed that WA induced significant apoptosis in Panc-1 cells in a dose-dependent manner. Western blotting demonstrated that WA inhibited Hsp90 chaperone activity to induce degradation of Hsp90 client proteins (Akt, Cdk4 and glucocorticoid receptor), which was reversed by the proteasomal inhibitor, MG132. WA-biotin pull down assay of Hsp90 using Panc-1 cancer cell lysates and purified Hsp90 showed that WA-biotin binds to C-terminus of Hsp90 which was competitively blocked by unlabeled WA. Co-immunoprecipitation exhibited that WA (10 μM) disrupted Hsp90-Cdc37 complexes from 1 to 24 h post-treatment, while it neither blocked ATP binding to Hsp90, nor changed Hsp90-P23 association. WA (3, 6 mg/kg) inhibited tumor growth in pancreatic Panc-1 xenografts by 30% and 58%, respectively. These data demonstrate that Withaferin A binds Hsp90, inhibits Hsp90 chaperone activity through an ATP-independent mechanism, results in Hsp90 client protein degradation, and exhibits in vivo anticancer activity against pancreatic cancer.

Original languageEnglish (US)
Pages (from-to)542-551
Number of pages10
JournalBiochemical Pharmacology
Volume79
Issue number4
DOIs
StatePublished - Feb 15 2010

Keywords

  • Cdc37
  • Client protein
  • Hsp90
  • Pancreatic cancer
  • Reactive cysteine
  • Withaferin A

ASJC Scopus subject areas

  • Biochemistry
  • Pharmacology

Fingerprint

Dive into the research topics of 'Withaferin A targets heat shock protein 90 in pancreatic cancer cells'. Together they form a unique fingerprint.

Cite this