Chemotherapeutic agents circumvent emergence of dasatinib-resistant BCR-ABL kinase mutations in a precise mouse model of Philadelphia chromosome–positive …

N Boulos, HL Mulder, CR Calabrese… - Blood, The Journal …, 2011 - ashpublications.org
N Boulos, HL Mulder, CR Calabrese, JB Morrison, JE Rehg, MV Relling, CJ Sherr…
Blood, The Journal of the American Society of Hematology, 2011ashpublications.org
The introduction of cultured p185BCR-ABL-expressing (p185+) Arf−/− pre-B cells into
healthy syngeneic mice induces aggressive acute lymphoblastic leukemia (ALL) that
genetically and phenotypically mimics the human disease. We adapted this high-throughput
Philadelphia chromosome–positive (Ph+) ALL animal model for in vivo luminescent imaging
to investigate disease progression, targeted therapeutic response, and ALL relapse in living
mice. Mice bearing high leukemic burdens (simulating human Ph+ ALL at diagnosis) …
Abstract
The introduction of cultured p185BCR-ABL-expressing (p185+) Arf−/− pre-B cells into healthy syngeneic mice induces aggressive acute lymphoblastic leukemia (ALL) that genetically and phenotypically mimics the human disease. We adapted this high-throughput Philadelphia chromosome–positive (Ph+) ALL animal model for in vivo luminescent imaging to investigate disease progression, targeted therapeutic response, and ALL relapse in living mice. Mice bearing high leukemic burdens (simulating human Ph+ ALL at diagnosis) entered remission on maximally intensive, twice-daily dasatinib therapy, but invariably relapsed with disseminated and/or central nervous system disease. Although relapse was frequently accompanied by the eventual appearance of leukemic clones harboring BCR-ABL kinase domain (KD) mutations that confer drug resistance, their clonal emergence required prolonged dasatinib exposure. KD P-loop mutations predominated in mice receiving less intensive therapy, whereas high-dose treatment selected for T315I “gatekeeper” mutations resistant to all 3 Food and Drug Administration–approved BCR-ABL kinase inhibitors. The addition of dexamethasone and/or L-asparaginase to reduced-intensity dasatinib therapy improved long-term survival of the majority of mice that received all 3 drugs. Although non–tumor-cell–autonomous mechanisms can prevent full eradication of dasatinib-refractory ALL in this clinically relevant model, the emergence of resistance to BCR-ABL kinase inhibitors can be effectively circumvented by the addition of “conventional” chemotherapeutic agents with alternate antileukemic mechanisms of action.
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