Supplemental Figure S1 shows the integration of CRISPR/Cas9 loss-of-function screens to identify dependencies and liabilities in BH3-mimetics treatments.
Supplemental Figure S2 demonstrates that increased mitochondria-ER interactions contribute to BH3-mimetics resistance.
Supplemental Figure S3 shows that mitophagy affects the responsiveness of AML cells to BH3-mimetics.
Supplemental Figure S4 reveals that enhanced autophagic clearance of mitochondria as a mechanism of resistance to BH3-mimetics in AML.
Supplemental Figure S5 exhibits the synergism between BH3-mimetics and macroautophagy inhibition in human AML.
Supplemental Figure S6 shows that deletion of MFN2 or MARCH5 sensitizes AML cells to BH3-mimetics.
Supplemental Figure S7 displays that targeting of MFN2 or MARCH5 impairs the process of mitophagy.
ARTICLE ABSTRACT
BH3-mimetics are used as an efficient strategy to induce cell death in several blood malignancies, including acute myeloid leukemia (AML). Venetoclax, a potent BCL-2 antagonist, is used clinically in combination with hypomethylating agents for the treatment of AML. Moreover, MCL-1 or dual BCL-2/BCL-xL antagonists are under investigation. Yet, resistance to single or combinatorial BH3-mimetics therapies eventually ensues. Integration of multiple genome-wide CRISPR/Cas9 screens revealed that loss of mitophagy modulators sensitizes AML cells to various BH3-mimetics targeting different BCL-2 family members. One such regulator is MFN2, whose protein levels positively correlate with drug resistance in patients with AML. MFN2 overexpression is sufficient to drive resistance to BH3-mimetics in AML. Insensitivity to BH3-mimetics is accompanied by enhanced mitochondria-endoplasmic reticulum interactions and augmented mitophagy flux which acts as a pro-survival mechanism to eliminate mitochondrial damage. Genetic or pharmacologic MFN2 targeting synergizes with BH3-mimetics by impairing mitochondrial clearance and enhancing apoptosis in AML.
