Targeting the Hsp90-associated viral oncoproteome in gammaherpesvirus-associated malignancies

Utthara Nayar, Pin Lu, Rebecca L. Goldstein, Jelena Vider, Gianna Ballon, Anna Rodina, Tony Taldone, Hediye Erdjument-Bromage, Max Chomet, Ronald Blasberg, Ari Melnick, Leandro Cerchietti, Gabriela Chiosis, Y. Lynn Wang, Ethel Cesarman

Research output: Contribution to journalArticlepeer-review

Abstract

PU-H71 is a purine-scaffold Hsp90 inhibitor that, in contrast to other Hsp90 inhibitors, displays unique selectivity for binding the fraction of Hsp90 that is preferentially associated with oncogenic client proteins and enriched in tumor cells (teHsp90). This property allows PU-H71 to potently suppress teHsp90 without inducing toxicity in normal cells. We found that lymphoma cells infected by Epstein-Barr virus or Kaposi sarcoma-associated herpes virus (KSHV) are exquisitely sensitive to this compound. Using PU-H71 affinity capture and proteomics, an unbiased approach to reveal oncogenic networks, we identified the teHsp90 interactome in KSHV+ primary effusion lymphoma cells. Viral and cellular proteins were identified, including many involved in nuclear factor (NF)-kB signaling, apoptosis, and autophagy. KSHV vFLIP is a viral oncoprotein homologous to cFLIPs, with NF-kB–activating and antiapoptotic activities. We show that teHsp90 binds vFLIP but not cFLIPs. Treatment with PU-H71 induced degradation of vFLIP and IKKg, NF-kB downregulation, apoptosis and autophagy in vitro, and more importantly, tumor responses in mice. Analysis of the interactome revealed apoptosis as a central pathway; therefore, we tested a BCL2 family inhibitor in primary effusion lymphoma cells. We found strong activity and synergy with PU-H71. Our findings demonstrate PU-H71 affinity capture identifies actionable networks that may help design rational combinations of effective therapies.

Original languageEnglish (US)
Pages (from-to)2837-2847
Number of pages11
JournalBlood
Volume122
Issue number16
DOIs
StatePublished - 2013
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Immunology
  • Hematology
  • Cell Biology

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