Evolution of transcriptomic profiles in relapsed inv(16) acute myeloid leukemia.

Acute myeloid leukemia (AML) with inv(16) is typically associated with a favourable prognosis. However, up to 40 % of patients will eventually experience disease relapse. Herein, we dissected the genomic and transcriptomic profile of inv(16) AML to identify potential prognostic markers and therapeutic vulnerabilities. Sequencing data from 222 diagnostic samples, including 44 relapse/refractory patients, revealed a median of 1 concomitant additional mutation, cooperating with inv(16) in leukemogenesis. Notably, the mutational landscape at diagnosis did not differ significantly between patients experiencing primary induction failure or relapse when compared to the rest of the cohort, except for an increase in the mutational burden in the relapse/refractory group. RNA-Seq of unpaired diagnostic(n=7) and relapse(n=6) samples allowed the identification of oxidative phosphorylation (OXPHOS) as one of the most significantly downregulated pathways at relapse. Considering that OXPHOS could be targeted by Venetoclax/Azacitidine combination, we explored its biological effects on an inv(16) cell-line ME-1, but there was no additional advantage in terms of cell death over Azacitidine alone. To enhance Venetoclax efficacy, we tested in vitro effects of Metformin as a potential drug able to enhance chemosensitivity of AML cells by inhibiting the mitochondrial transfer. By challenging ME-1 with this combination, we observed a significant synergistic interaction at least similar to that of Venetoclax/Azacitidine. In conclusions, we identified a downregulated expression of oxidative phosphorylation (OXPHOS) at relapse in AML with inv(16), and explored the in vitro effects of metformin as a potential drug to enhance chemosensitivity in this setting.