Publication Date:
2016-12-02
Description:
Introduction: Philadelphia chromosome-like acute lymphoblastic leukemia (Ph-like ALL) is a high-risk subtype characterized by kinase-activating alterations. One recurrent alteration is the ETV6-NTRK3 fusion, which results in constitutive activation of NTRK3, a member of the neurotrophic receptor kinase family. ETV6-NTRK3 has been identified in a range of malignancies, including breast cancer, pediatric glioma and infantile fibrosarcoma. The oncogenic role of ETV6-NTRK3 in B-cell ALL has not been investigated. The goals of this study were to assess the development of leukemia in genetically engineered models of ETV6-NTRK3, and to investigate efficacy of the specific TRK A, B and C inhibitor, LOXO-101, currently in clinical trials for the treatment of solid tumor patients who harbor NTRK fusions. Methods: For in vitro studies, kinase fusions were expressed in IL3 dependent Ba/F3 cells. To generate a genetically engineered mouse model, we used a previously reported conditional knockin model of Etv6-NTRK3 (Cancer Cell 2007;12:542-558), whereby the human portion of NTRK3 cDNA encoding the tyrosine kinase domain was inserted into exon 6 of the mouse Etv6 locus, downstream of a floxed transcriptional terminator sequence. Expression of the Etv6-NTRK3 protein was accomplished using Cre-recombinase driven by the B-lineage promoter CD19. A patient derived xenograft (PDX) model of ETV6-NTRK3 was established by engrafting primary human ALL cells expressing luciferase into NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NSG) mice. Phosphoflow cytometry analysis and sensitivity to LOXO-101 was assessed in vitro and in vivo. Results: Etv6-NTRK3/+, CD19-Cre mice developed aggressive disease with 100% penetrance and a median latency of 38 days (n=27). The average body weight of Etv6-NTRK3/+, CD19-Cre mice was significantly reduced compared to age-matched Etv6-NTRK3/+ controls (13.9 vs 20.2g, p
Print ISSN:
0006-4971
Electronic ISSN:
1528-0020
Topics:
Biology
,
Medicine
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