Inhibition of MEK and ATR is effective in a B-cell acute lymphoblastic leukemia model driven by Mll-Af4and activated Ras

Autor: Chu, S. Haihua, Song, Evelyn J., Chabon, Jonathan R., Minehart, Janna, Matovina, Chloe N., Makofske, Jessica L., Frank, Elizabeth S., Ross, Kenneth, Koche, Richard P., Feng, Zhaohui, Xu, Haiming, Krivtsov, Andrei, Nussenzweig, Andre, Armstrong, Scott A.
Zdroj: Blood Advances; October 2018, Vol. 2 Issue: 19 p2478-2490, 13p
Abstrakt: Infant B-cell acute lymphoblastic leukemias (B-ALLs) that harbor MLL-AF4rearrangements are associated with a poor prognosis. One important obstacle to progress for this patient population is the lack of immunocompetent models that faithfully recapitulate the short latency and aggressiveness of this disease. Recent whole-genome sequencing of MLL-AF4B-ALL samples revealed a high frequency of activating RASmutations; however, single-agent targeting of downstream effectors of the RASpathway in these mutated MLL-r B-ALLs has demonstrated limited and nondurable antileukemic effects. Here, we demonstrate that the expression of activating mutant N-RasG12Dcooperates with Mll-Af4to generate a highly aggressive serially transplantable B-ALL in mice. We used our novel mouse model to test the sensitivity of Mll-Af4/N-RasG12Dleukemia to small molecule inhibitors and found potent and synergistic preclinical efficacy of dual targeting of the Mek and Atr pathways in mouse- and patient-derived xenografts with both mutations in vivo, suggesting this combination as an attractive therapeutic opportunity that might be used to treat patients with these mutations. Our studies indicate that this mouse model of Mll-Af4/N-RasB-ALL is a powerful tool to explore the molecular and genetic pathogenesis of this disease subtype, as well as a preclinical discovery platform for novel therapeutic strategies.
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