title: Quantitative phosphotyrosine profiling of patient-derived xenografts identifies therapeutic targets in pediatric leukemia.
abstract: Activating mutations in tyrosine kinases (TKs) drive pediatric high-risk acute lymphoblastic leukemia (ALL) and confer resistance to standard chemotherapy. Therefore, there is urgent need to characterize dysregulated TK signaling axes in patients with ALL and identify actionable kinase targets for the development of therapeutic strategies. Here, we present the first study to quantitatively profile TK activity in xenografted patient biopsies of high-risk pediatric ALL. We integrated a quantitative phosphotyrosine profiling method with 'spike-in' stable isotope labeling with amino acids in cell culture (SILAC) and quantified 1394 class I phosphorylation sites in 16 ALL xenografts. Moreover, hierarchical clustering of phosphotyrosine sites could accurately classify these leukemias into either B or T-cell lineages with the high-risk early T-cell precursor (ETP) and Ph-like ALL clustering as a distinct group. Furthermore, we validated this approach by using specific kinase pathway inhibitors to perturb ABL1, FLT3, and JAK TK signaling in four xenografted patient samples. By quantitatively assessing the tyrosine phosphorylation status of activated kinases in xenograft models of ALL, we were able to identify and validate clinically relevant targets. Therefore, this study highlights the application and potential of phosphotyrosine profiling for identifying clinically relevant kinase targets in leukemia.
authors.affiliation: Leukemia Biology, Childrens Cancer Institute.
authors.forename: Sibasish
authors.initials: S
authors.lastname: Dolai
authors.affiliation: Leukaemia Biology, Children's Cancer Institute.
authors.forename: Keith C S
authors.initials: KC
authors.lastname: Sia
authors.affiliation: Leukaemia Biology Program, Childrens Cancer Institute.
authors.forename: Alissa K
authors.initials: AK
authors.lastname: Robbins
authors.affiliation: Mark Wainwright Analytical Centre, Bioanalytical Mass Spectrometry Facility.
authors.forename: Ling
authors.initials: L
authors.lastname: Zhong
authors.affiliation: Cancer Theme, South Australian Health and Medical Research Institute (SAHMRI).
authors.forename: Sue L
authors.initials: SL
authors.lastname: Heatley
authors.affiliation: Divison of Oncology, Children's Hospital of Philadelphia.
authors.forename: Tiffaney L
authors.initials: TL
authors.lastname: Vincent
authors.affiliation: Competence Center Functional Genomics, University of Greifswald.
authors.forename: Falko
authors.initials: F
authors.lastname: Hochgräfe
authors.affiliation: Leukaemia Biology, Children's Cancer Institute.
authors.forename: Rosemary
authors.initials: R
authors.lastname: Sutton
authors.affiliation: Molecular Medicine, UTHSC San Antonio.
authors.forename: Raushan T
authors.initials: RT
authors.lastname: Kurmasheva
authors.affiliation: Women's & Children's Hospital, SA Pathology.
authors.forename: Tamas
authors.initials: T
authors.lastname: Revesz
authors.affiliation: Cancer Theme, SAHMRI.
authors.forename: Deborah L
authors.initials: DL
authors.lastname: White
authors.affiliation: Greehey Children's Cancer Research Institute, The University of Texas Health Science Center at San Antonio.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Houghton
authors.affiliation: Cancer Therapy Evaulation Program, National Cancer Institute.
authors.forename: Malcolm A
authors.initials: MA
authors.lastname: Smith
authors.affiliation: Oncology, Children's Hospital of Philadelphia.
authors.forename: David T
authors.initials: DT
authors.lastname: Teachey
authors.affiliation: Department of Biochemistry and Molecular Biology, Monash University.
authors.forename: Roger J
authors.initials: RJ
authors.lastname: Daly
authors.affiliation: Bioanalytical Mass Spectrometry Facility, University of New South Wales.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Raftery
authors.affiliation: Children's Cancer Institute Australia for Medical Research, Lowy Cancer Research Centre, UNSW rlock@ccia.org.au.
authors.forename: Richard B
authors.initials: RB
authors.lastname: Lock