PT  - JOURNAL ARTICLE
AU  - Shuai Ye
AU  - Dinara Sharipova
AU  - Marya Kozinova
AU  - Lilli Klug
AU  - Jimson D’Souza
AU  - Martin G. Belinsky
AU  - Katherine J. Johnson
AU  - Margret B. Einarson
AU  - Kathy Cai
AU  - Karthik Devarajan
AU  - Yan Zhou
AU  - Samuel Litwin
AU  - Michael C. Heinrich
AU  - Ronald DeMatteo
AU  - Margaret von Mehren
AU  - James Duncan
AU  - Lori Rink
TI  - Kinome Profiling of Gastrointestinal Stromal Tumors Using Multiplexed Inhibitor Beads and Mass Spectrometry Identifies Wee1 as Candidate Therapeutic Target
AID  - 10.1101/2020.06.07.138693
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.06.07.138693
4099  - http://biorxiv.org/content/early/2020/06/08/2020.06.07.138693.short
4100  - http://biorxiv.org/content/early/2020/06/08/2020.06.07.138693.full
AB  - Gastrointestinal stromal tumor (GIST) management has been revolutionized by the identification of activating mutations in KIT and PDGFRA and clinical application of receptor tyrosine kinase (RTK) inhibitors in advanced disease. Stratification of GIST into molecularly defined subsets provides insight into clinical behavior and response to approved targeted therapies. Although these RTK inhibitors are effective in most GIST, resistance remains a significant clinical obstacle. Development of effective strategies for refractory GIST requires identification of novel targets to provide additional therapeutic options. Global kinome profiling has potential to identify critical signaling networks and reveal protein kinases that are essential in GIST. Using Multiplexed Inhibitor Beads and Mass Spectrometry paired with a super-SILAC kinome standard, we explored the majority of the kinome in GIST specimens from the three most common molecular subtypes to identify novel kinase targets. Kinome profiling revealed distinct signatures in GIST subtypes. PDGFRA-mutant GIST had elevated tumor associated macrophage (TAM) kinases and immunohistochemical analysis confirmed increased TAMs present in these tumors. Kinome profiling with loss-of-function assays revealed a significant role for G2-M tyrosine kinase, Wee1, in GIST survival. In vitro and in vivo studies revealed significant efficacy of MK-1775 (Wee1 inhibitor) in combination with avapritinib in KIT and PDGFRA-mutant GIST cell lines, and notable efficacy of MK-1775 as a monotherapy in the PDGFRA-mutant line. These studies provide strong preclinical justification for the use of MK-1775 in GIST.Competing Interest StatementThe authors have declared no competing interest.