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The PDK1 master kinase is over-expressed in acute myeloid leukemia and promotes PKC-mediated survival of leukemic blasts
journal contribution
posted on 2023-06-09, 13:12 authored by Joanna Zabkiewicz, Lorna Pearn, Robert K Hills, Rhys MorganRhys Morgan, Alex Tonks, Alan K Burnett, Richard L DarleyPDK1 is a master kinase that activates at least six protein kinase groups including AKT, PKC and S6K and is a potential target in the treatment of a range of malignancies. Here we show overexpression of PDK1 in over 40% of myelomonocytic acute leukemia patients. Overexpression of PDK1 occurred uniformly throughout the leukemic population, including putative leukemia-initiating cells. Clinical outcome analysis revealed PDK1 overexpression was associated with poorer treatment outcome. Primary acute myeloid leukemia blasts over-expressing PDK1 showed improved in vitro survival and ectopic expression of PDK1 promoted the survival of myeloid cell lines. Analysis of PDK1 target kinases revealed that PDK1 overexpression was most closely associated with increased phosphorylation of PKC isoenzymes and inhibition of PKC strongly inhibited the survival advantage of PDK1 over-expressing cells. Membrane localization studies implicated PKCa as a major target for PDK1 in this disease. PDK1 over-expressing blasts showed differential sensitivity to PDK1 inhibition (in the low micromolar range) suggesting oncogene addiction, whilst normal bone marrow progenitors were refractory to PDK1 inhibition at effective inhibitor concentrations. PDK1 inhibition also targeted subpopulations of leukemic blasts with a putative leukemia-initiating cell phenotype. Together these data show that overexpression of PDK1 is common in acute myelomonocytic leukemia and is associated with poorer treatment outcome, probably arising from the cytoprotective function of PDK1. We also show that therapeutic targeting of PDK1 has the potential to be both an effective and selective treatment for these patients, and is also compatible with current treatment regimes.
History
Publication status
- Published
File Version
- Published version
Journal
HaematologicaISSN
1592-8721Publisher
Ferrata Storti FoundationExternal DOI
Issue
5Volume
99Page range
858-864Department affiliated with
- Biochemistry Publications
Research groups affiliated with
- Haematology Research Group Publications
Full text available
- Yes
Peer reviewed?
- Yes
Legacy Posted Date
2018-05-10First Open Access (FOA) Date
2018-05-10First Compliant Deposit (FCD) Date
2018-05-09Usage metrics
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