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Biology subjects

Eide, C. A.

Publications and source records attributed to Eide, C. A..

2 recordsLinked to original sources

A Rapid Gene Expression Profiler Classifies AML Tumor Responsiveness to Standard Therapies

The emergence of transcriptional signatures that define cell types and pathways has made it possible to guide cancer therapy selection through gene expression profiling. We developed a rapid qPCR-based platform to profile cell state, stemness, and BCL2 family gene expression as a companion diagnostic test for acute myeloid leukemia (AML). We validated the stability and utility of the signatures across multiple measurement platforms and using patient samples from two centers. Integrating these signatures with clinical features enables an expedient means to predict the likelihood of patient responses to two standard-of-care therapies: intensive chemotherapy and hypomethylating agent plus venetoclax (HMA+Ven). For patients treated with HMA+Ven, expression levels of the promonocyte-like signature and BCL2 add predictive value for response and overall survival in multivariable models that include genetic features. The incorporation of the rapid profiler into the prospective evaluation of newly diagnosed AML patients may enhance treatment stratification and improve outcomes.

cancer biology↗

Autophosphorylation of the oncogenic protein TEL-ABL confers resistance to the allosteric ABL inhibitor asciminib

Chromosomal translocations that fuse the ABL1 gene to BCR and TEL cause human leukemias. Oligomerization and the loss of an inhibitory myristoylation modification lead to unregulated kinase activity of the BCR-ABL and TEL-ABL fusion proteins. ATP-competitive ABL inhibitors, such as imatinib and ponatinib, are effective against both fusion proteins. We discovered that asciminib, an allosteric inhibitor of BCR-ABL that binds to the myristoyl binding site in the ABL kinase domain, is >2000-fold less potent against TEL-ABL than BCR-ABL in cell-growth assays. This is surprising because the ABL components of the two fusion proteins, including the asciminib binding sites, have identical sequence. We deleted a short helical segment in the ABL kinase domain that closes over asciminib when it is bound. This deletion results in asciminib resistance in BCR-ABL, but has no effect on TEL-ABL, suggesting that the native autoinhibitory mechanism that asciminib engages in BCR-ABL is disrupted in TEL-ABL. We show, using mammalian cell expression and single-molecule microscopy, that BCR-ABL is mainly dimeric while TEL-ABL forms higher-order oligomers. Oligomerization can promote trans-autophosphorylation of ABL, and we find that a regulatory phosphorylation site in the SH3 domain of ABL (Tyr 89) is highly phosphorylated in TEL-ABL. This phosphorylation is expected to disassemble the autoinhibited conformation of ABL, thereby preventing asciminib binding. We show that TEL-ABL is intrinsically susceptible to inhibition by asciminib, but that increased phosphorylation results in resistance. Our results demonstrate that different ABL fusion proteins can have dramatically different responses to allosteric inhibitors due to differential phosphorylation. One Sentence SummaryWhen TEL-ABL is phosphorylated, it is insensitive to asciminib. However, when TEL-ABL is dephosphorylated by a phosphatase, asciminib sensitivity is restored.

biochemistry↗