Erythroid/megakaryocytic differentiation confers BCL-XL dependency and venetoclax resistance in acute myeloid leukemia

• Published in: Blood Vol. 141; no. 13; pp. 1610 - 1625
• Main Authors: Kuusanmäki, Heikki, Dufva, Olli, Vähä-Koskela, Markus, Leppä, Aino-Maija, Huuhtanen, Jani, Vänttinen, Ida, Nygren, Petra, Klievink, Jay, Bouhlal, Jonas, Pölönen, Petri, Zhang, Qi, Adnan-Awad, Shady, Mancebo-Pérez, Cristina, Saad, Joseph, Miettinen, Juho, Javarappa, Komal K., Aakko, Sofia, Ruokoranta, Tanja, Eldfors, Samuli, Heinäniemi, Merja, Theilgaard-Mönch, Kim, Wartiovaara-Kautto, Ulla, Keränen, Mikko, Porkka, Kimmo, Konopleva, Marina, Wennerberg, Krister, Kontro, Mika, Heckman, Caroline A., Mustjoki, Satu
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 30-03-2023
• Subjects: Animals; Apoptosis; bcl-X Protein - genetics; Bridged Bicyclo Compounds, Heterocyclic - pharmacology; Bridged Bicyclo Compounds, Heterocyclic - therapeutic use; Cell Differentiation; Cell Line, Tumor; Humans; Leukemia, Megakaryoblastic, Acute - drug therapy; Leukemia, Megakaryoblastic, Acute - genetics; Leukemia, Myeloid, Acute - drug therapy; Leukemia, Myeloid, Acute - genetics; Leukemia, Myeloid, Acute - metabolism; Lymphoma, B-Cell; Mice; Myeloid Cell Leukemia Sequence 1 Protein - genetics; Proto-Oncogene Proteins c-bcl-2 - genetics
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.2021011094

•High-throughput screening of >500 drugs identifies BCL-XL inhibitor sensitivity and venetoclax resistance in erythroid/megakaryocytic AML.•BCL2L1 (BCL-XL) is highly expressed in erythroid/megakaryocytic AML and is essential for their survival based on CRISPR screens.
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Myeloid neoplasms with erythroid or megakaryocytic differentiation include pure erythroid leukemia, myelodysplastic syndrome with erythroid features, and acute megakaryoblastic leukemia (FAB M7) and are characterized by poor prognosis and limited treatment options. Here, we investigate the drug sensitivity landscape of these rare malignancies. We show that acute myeloid leukemia (AML) cells with erythroid or megakaryocytic differentiation depend on the antiapoptotic protein B-cell lymphoma (BCL)-XL, rather than BCL-2, using combined ex vivo drug sensitivity testing, genetic perturbation, and transcriptomic profiling. High-throughput screening of >500 compounds identified the BCL-XL–selective inhibitor A-1331852 and navitoclax as highly effective against erythroid/megakaryoblastic leukemia cell lines. In contrast, these AML subtypes were resistant to the BCL-2 inhibitor venetoclax, which is used clinically in the treatment of AML. Consistently, genome-scale CRISPR-Cas9 and RNAi screening data demonstrated the striking essentiality of BCL-XL-encoding BCL2L1 but not BCL2 or MCL1, for the survival of erythroid/megakaryoblastic leukemia cell lines. Single-cell and bulk transcriptomics of patient samples with erythroid and megakaryoblastic leukemias identified high BCL2L1 expression compared with other subtypes of AML and other hematological malignancies, where BCL2 and MCL1 were more prominent. BCL-XL inhibition effectively killed blasts in samples from patients with AML with erythroid or megakaryocytic differentiation ex vivo and reduced tumor burden in a mouse erythroleukemia xenograft model. Combining the BCL-XL inhibitor with the JAK inhibitor ruxolitinib showed synergistic and durable responses in cell lines. Our results suggest targeting BCL-XL as a potential therapy option in erythroid/megakaryoblastic leukemias and highlight an AML subgroup with potentially reduced sensitivity to venetoclax-based treatments.
Acute myeloid leukemia (AML) with erythroid or megakaryocytic differentiation (pure erythroid leukemia, myelodysplastic syndrome with erythroid features, and acute megakaryocytic leukemia) has a poor response to therapy and a poor prognosis. Kuusanmäki and colleagues report on a high-throughput screen to identify potential drugs with improved efficacy. The authors show that these subtypes depend on BCL-XL and not on BCL2 or MCL; consequently, BCL-XL inhibition was effective in cell lines and primary cells that were resistant to venetoclax.