Resistance to HSP90 inhibition involving loss of MCL1 addiction

Sara Busacca, Edward WP Law, Ian R Powley, David A Proia, Manuel Sequeira, John Le Quesne, Astero Klabatsa, Jennifer M Edwards, Kyle B Matchett, Jinli Luo, J Howard Pringle, Mohamed El-Tanani, Marion MacFarlane, Dean A Fennell

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)
30 Downloads (Pure)


Inhibition of the chaperone heat-shock protein 90 (HSP90) induces apoptosis, and it is a promising anti-cancer strategy. The mechanisms underpinning apoptosis activation following HSP90 inhibition and how they are modified during acquired drug resistance are unknown. We show for the first time that, to induce apoptosis, HSP90 inhibition requires the cooperation of multi BH3-only proteins (BID, BIK, PUMA) and the reciprocal suppression of the pro-survival BCL-2 family member MCL1, which occurs via inhibition of STAT5A. A subset of tumour cell lines exhibit dependence on MCL1 expression for survival and this dependence is also associated with tumour response to HSP90 inhibition. In the acquired resistance setting, MCL1 suppression in response to HSP90 inhibitors is maintained; however, a switch in MCL1 dependence occurs. This can be exploited by the BH3 peptidomimetic ABT737, through non-BCL-2-dependent synthetic lethality.
Original languageEnglish
Pages (from-to)1483-1492
Number of pages10
Early online date22 Jun 2015
Publication statusPublished (in print/issue) - 24 Mar 2016


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