Antileukemic Efficacy of BET Inhibitor in a Preclinical Mouse Model of MLL-AF4+ Infant ALL

We investigated the anti-leukemic effects of the Bromodomain and Extra Terminal inhibitor I-BET151 on primary MLL-AF4 patient samples, using a xenotransplantation mouse model of MLL+ infant ALL in vivo. We reported that I-BET151 treatment impairs the engraftment and the disease burden of primary MLL+ infant ALL samples transplanted into immunedeficient mice. I-BET151 is able to arrest the growth of leukemic cells by blocking cell division and rapidly inducing apoptosis, through the deregulation of crucial target genes of the BRD4 and HOXA9/HOXA7 network. Moreover I-BET151 sensitizes glucocorticoid-resistant MLL+ cells to Prednisolone. Finally we observed that I-BET151 treatment is even more efficient when used in combination with HDAC inhibitor.

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Bardini M, Trentin L, Rizzo F, Vieri M, Savino AM, Garrido Castro P, Fazio G, Van Roon EHJ, Kerstjens M, Smithers N, Prinjha RK, Te Kronnie G, Basso G, Stam RW, Pieters R, Biondi A, Cazzaniga G