Abstract
Amanda M. Smith1,4,*, Christine R.C. Zhang1,4,*, Alexandre S. Cristino1,6, John P. Grady1,5, J. Lynn Fink1 and Andrew S. Moore1,2,3,4
1 The University of Queensland Diamantina Institute, The University of Queensland, Woolloongabba, Australia
2 Oncology Services Group, Queensland Children’s Hospital, South Brisbane, Australia
3 Child Health Research Centre, The University of Queensland, South Brisbane, Australia
4 Current address: Washington University in Saint Louis, Saint Louis, Missouri, United States of America
5 Current address: Garvan Institute of Medical Research, Darlinghurst, Australia
6 Current address: Griffith Institute for Drug Discovery, Brisbane Innovation Park, Nathan, Australia
* These authors contributed equally to this work
Correspondence to:
Andrew S. Moore, | email: | andy.moore@health.qld.gov.au |
J. Lynn Fink, | email: | l.fink@uq.edu.au |
Keywords: myeloid leukemia; therapy; drug resistance; hematological malignancies; gene mutation
Abbreviations: MEKi: MEK inhibitor(s); TR: THP-1 cells with resistance to AZD6244
Received: January 30, 2019 Accepted: August 12, 2019 Published: October 08, 2019
ABSTRACT
Kinases such as MEK are attractive targets for novel therapy in cancer, including acute myeloid leukaemia (AML). Acquired and inherent resistance to kinase inhibitors, however, is becoming an increasingly important challenge for the clinical success of such therapeutics, and often arises from mutations in the drug-binding domain of the target kinase. To identify possible causes of resistance to MEK inhibition, we generated a model of resistance by long-term treatment of AML cells with AZD6244 (selumetinib). Remarkably, resistance to MEK inhibition was due to acquired PTEN haploinsufficiency, rather than mutation of MEK. Resistance via this mechanism was confirmed using CRISPR/Cas9 technology targeting exon 5 of PTEN. While PTEN loss has been previously implicated in resistance to a number of other therapeutic agents, this is the first time that it has been shown directly and in AML.