A Hyperactive Signalosome in Acute Myeloid Leukemia Drives Addiction to a Tumor-Specific Hsp90 Species

• AML cells with hyperactivated signaling networks become dependent on teHsp90
• This AML addiction results in vulnerability to inhibitors of teHsp90 function
• Leukemias with hyperactivated networks are likely candidates for teHsp90i therapy

SummaryAcute myeloid leukemia (AML) is a heterogeneous and fatal disease with an urgent need for improved therapeutic regimens given that most patients die from relapsed disease. Irrespective of mutation status, the development of aggressive leukemias is enabled by increasing dependence on signaling networks. We demonstrate that a hyperactive signalosome drives addiction of AML cells to a tumor-specific Hsp90 species (teHsp90). Through genetic, environmental, and pharmacologic perturbations, we demonstrate a direct and quantitative link between hyperactivated signaling pathways and apoptotic sensitivity of AML to teHsp90 inhibition. Specifically, we find that hyperactive JAK-STAT and PI3K-AKT signaling networks are maintained by teHsp90 and, in fact, gradual activation of these networks drives tumors increasingly dependent on teHsp90. Thus, although clinically aggressive AML survives via signalosome activation, this addiction creates a vulnerability that can be exploited with Hsp90-directed therapy.

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