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R. Birsen et al.
impairment (Figure 6D and E; Online Supplementary Figure S5). The association of erastin and APR-246 also had a synergistic effect on cell viability in five primary AML samples (Figure 6F). There was no correlation between the basal levels of GPX4 and SLC7A11 proteins and the sensitivity to APR-246 (Online Supplementary Figure S6A and B). Altogether, these data suggest that the ability of AML cells to prevent lipid peroxides accumulation by increasing their cystine uptake to support GSH after
exposure to APR-246 is a key determinant of the sensitiv- ity to this compound.
The association of APR-246 and ferroptosis inducers has a synergistic anti-leukemic activity in vitro
We next determined whether targeting ferroptosis path- ways in combination with APR-246 can increase the anti- leukemic activity of this compound, mimicking SLC7A11 inhibition.DownregulationofGPX4byRNAinterference
A
C
D
Figure 5. SLC7A11 overexpression prevents glutathione depletion and cell death following APR-246 exposure. (A) Cystine uptake in MOLM-14 and OCI-AML2 cells lines at 16 hours (h) post-APR-246 (100 mM) and Fer1 (10 mM) treatment. Fer1 was associated to prevent cell death and allowed analysis of cystine uptake. (B) Immunoblotting analysis of SLC7A11 in MOLM-14 cells treated for 16 h with dimethyl sulfoxide (DMSO) or APR-246 (n=2). b-actin was used as a loading control. (C and D) Cell death (%) (C) and glutathione (GSH) (mBCI) measurement (D) of the indicated cells at 20 h post-APR-246 treatment (n=3). For GSH measurement, Fer1 was associated to prevent cell death and allowed analysis of GSH depletion. Error bars ± standard deviation. Statistics by t-test. *P<0.05, **P<0.01, ***P<0.0001.
B
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haematologica | 2022; 107(2)