Targeting SUMOylation sensitizes Acute myeloid leukemia to Venetoclax treatment
Ontology highlight
ABSTRACT: Acute myeloid leukemia (AML) is a hematopoietic cancer characterized by the proliferation and accumulation of aberrant immature myeloid progenitor blasts in bone marrow and peripheral blood. Venetoclax (VEN), a selective B-cell lymphoma 2 (BCL-2) inhibitor, has received FDA approval for AML treatment in combination with hypomethylating agents (HMA). However, treatment failure and therapy resistance present an urgent need for new therapies to overcome VEN resistance and enhance VEN efficacy. We propose inhibition of SUMOylation as a novel therapy with the potential to address this need. SUMOylation regulates protein function by covalently attaching Small Ubiquitin-like MOdifier (SUMO) proteins to target proteins via an enzymatic cascade. Our study aims to evaluate the effects of SUMOylation inhibition on anti-AML activity of VEN and dissert the underlying mechanism.
Project description:Therapy resistance represents a major clinical challenge in acute myeloid leukemia (AML). Here we define a “MitoScore” signature that identifies high mitochondrial oxidative phosphorylation (OxPHOS) in vivo and in AML patients. Primary AML cells with cytarabine (AraC) resistance and high MitoScore relied on mitochondrial Bcl2 and were highly sensitive to venetoclax (VEN) plus AraC (but not to VEN plus azacytidine, AZA). Single-cell transcriptomics of VEN+AraC-residual cell populations revealed adaptive resistance associated with changes in OxPHOS, electron transport chain complex (ETC) and the TP53 pathway.
Project description:The combination of venetoclax with azacitidine (ven/aza) has recently emerged as a promising regimen for acute myeloid leukemia (AML), with approximately 70% of newly diagnosed patients achieving complete remission (CR). However, 30% of newly diagnosed and nearly all relapsed patients do not achieve CR with ven/aza. Mechanistically, we previously reported that ven/aza efficacy is based on eradication of AML stem cells through a mechanism involving inhibition of amino acid metabolism, a process which is required in primitive AML cells to drive oxidative phosphorylation. In the present study we demonstrate that resistance to ven/aza occurs as a consequence of up-regulated fatty acid oxidation (FAO), which occurs either as an intrinsic property of RAS pathway mutations, or as a compensatory adaptation in relapsed disease. Utilization of FAO obviates the need for amino acid metabolism into the TCA cycle, thereby rendering ven/aza ineffective. Importantly, we show that pharmacological inhibition of FAO via use of MCL-1 or CPT1 inhibitor drugs restores targeting of ven/aza resistant AML stem cells. Based on these findings we propose that inhibition of FAO is a potential therapeutic strategy to address ven/aza resistance.
Project description:The combination of venetoclax with azacitidine (ven/aza) has recently emerged as a promising regimen for acute myeloid leukemia (AML), with approximately 70% of newly diagnosed patients achieving complete remission (CR). However, 30% of newly diagnosed and nearly all relapsed patients do not achieve CR with ven/aza. Mechanistically, we previously reported that ven/aza efficacy is based on eradication of AML stem cells through a mechanism involving inhibition of amino acid metabolism, a process which is required in primitive AML cells to drive oxidative phosphorylation. In the present study we demonstrate that resistance to ven/aza occurs as a consequence of up-regulated fatty acid oxidation (FAO), which occurs either as an intrinsic property of RAS pathway mutations, or as a compensatory adaptation in relapsed disease. Utilization of FAO obviates the need for amino acid metabolism into the TCA cycle, thereby rendering ven/aza ineffective. Importantly, we show that pharmacological inhibition of FAO via use of MCL-1 or CPT1 inhibitor drugs restores targeting of ven/aza resistant AML stem cells. Based on these findings we propose that inhibition of FAO is a potential therapeutic strategy to address ven/aza resistance.
Project description:Hypomethylating agents (HMAs) are frontline therapies effective at altering the natural course of Myelodysplastic Neoplasms (MDS). However, acquired resistance and treatment failure are hallmarks of HMA therapy. Developing effective and rational HMA-focused combinatorial therapies is challenging as the underlying mechanisms driving HMA efficacy are complex. To address this clinical need, we performed a genome-wide CRISPR-Cas9 screen in a human MDS-derived cell line, MDS-L, and characterized TOPORS as a highly ranked target that synergizes with HMAs to reduce leukemic burden and improve survival in xenograft models. We demonstrated that the depletion of TOPORS mediates sensitivity to HMAs by predisposing leukemic blasts to an impaired DNA damage response (DDR) accompanied by an accumulation of SUMOylated DNMT1 in HMA-treated TOPORS-depleted cells. Importantly, the combination of HMAs with targeting of TOPORS did not functionally impair healthy hematopoiesis. While inhibitors of TOPORS are currently unavailable, we show that inhibition of SUMOylation (upstream of TOPORS functions) with TAK-981 partially phenocopies HMA-sensitivity and DDR impairment. Overall, our data suggest that the combination of HMAs with the inhibition of SUMOylation demonstrates a favourable therapeutic index and represents a rational framework towards the treatment of High-Risk MDS (HR-MDS) or Acute Myeloid Leukemia (AML).
Project description:Hypomethylating agents (HMAs) are frontline therapies effective at altering the natural course of Myelodysplastic Neoplasms (MDS). However, acquired resistance and treatment failure are hallmarks of HMA therapy. Developing effective and rational HMA-focused combinatorial therapies is challenging as the underlying mechanisms driving HMA efficacy are complex. To address this clinical need, we performed a genome-wide CRISPR-Cas9 screen in a human MDS-derived cell line, MDS-L, and characterized TOPORS as a highly ranked target that synergizes with HMAs to reduce leukemic burden and improve survival in xenograft models. We demonstrated that the depletion of TOPORS mediates sensitivity to HMAs by predisposing leukemic blasts to an impaired DNA damage response (DDR) accompanied by an accumulation of SUMOylated DNMT1 in HMA-treated TOPORS-depleted cells. Importantly, the combination of HMAs with targeting of TOPORS did not functionally impair healthy hematopoiesis. While inhibitors of TOPORS are currently unavailable, we show that inhibition of SUMOylation (upstream of TOPORS functions) with TAK-981 partially phenocopies HMA-sensitivity and DDR impairment. Overall, our data suggest that the combination of HMAs with the inhibition of SUMOylation demonstrates a favourable therapeutic index and represents a rational framework towards the treatment of High-Risk MDS (HR-MDS) or Acute Myeloid Leukemia (AML).
Project description:Hypomethylating agents (HMAs) are frontline therapies effective at altering the natural course of Myelodysplastic Neoplasms (MDS). However, acquired resistance and treatment failure are hallmarks of HMA therapy. Developing effective and rational HMA-focused combinatorial therapies is challenging as the underlying mechanisms driving HMA efficacy are complex. To address this clinical need, we performed a genome-wide CRISPR-Cas9 screen in a human MDS-derived cell line, MDS-L, and characterized TOPORS as a highly ranked target that synergizes with HMAs to reduce leukemic burden and improve survival in xenograft models. We demonstrated that the depletion of TOPORS mediates sensitivity to HMAs by predisposing leukemic blasts to an impaired DNA damage response (DDR) accompanied by an accumulation of SUMOylated DNMT1 in HMA-treated TOPORS-depleted cells. Importantly, the combination of HMAs with targeting of TOPORS did not functionally impair healthy hematopoiesis. While inhibitors of TOPORS are currently unavailable, we show that inhibition of SUMOylation (upstream of TOPORS functions) with TAK-981 partially phenocopies HMA-sensitivity and DDR impairment. Overall, our data suggest that the combination of HMAs with the inhibition of SUMOylation demonstrates a favourable therapeutic index and represents a rational framework towards the treatment of High-Risk MDS (HR-MDS) or Acute Myeloid Leukemia (AML).
Project description:Deep single-cell multi-omic profiling of drug resistance in patients with relapsed or refractory (rr) acute myeloid leukemia (AML) is a promising approach to understand and identify the molecular and cellular determinants of drug resistance. Here, we address this challenge by integrating single-cell ex vivo drug profiling (pharmacoscopy) with both bulk and single-cell resolved DNA, RNA, and protein profiling, as well as clinical annotations across samples of a cohort of 21 rrAML patients. Unsupervised data integration revealed ex vivo response to the Bcl-2 inhibitor venetoclax (VEN) to be significantly reduced in patients treated with the combination of a hypomethylating agent (HMA) and VEN compared to patients pre-exposed to HMA only, while also exposing innate Ven resistance in a subset of VEN-naive patients. Systematic molecular integration retrieved known and novel molecular mechanisms underlying VEN resistance and identified alternative therapeutic strategies in VEN resistant samples, including targeting increased proliferation by PLK inhibitor volasertib. Across data modalities, high CD36 expression on AML blasts was associated with VENres, while CD36-targeted antibody treatment ex vivo revealed striking sensitivity in VEN resistant AML. In summary, we showcase how single-cell multi-omic and functional profiling can facilitate the discovery of drug resistance mechanisms and emergent treatment vulnerabilities. Our dataset represents a comprehensive molecular and functional profiling of rrAML at single-cell resolution, providing a valuable resource for future studies.
Project description:The BCL-2 family plays important roles in acute myeloid leukemia (AML) and Venetoclax, a selective BCL-2 inhibitor, has received FDA approval for treatment of AML. However, drug resistance ensues after prolonged treatment, highlighting the need for a greater understanding of the underlying mechanisms. Using a genome-wide CRISPR/Cas9 screen in human AML, we identified genes whose inactivation sensitizes AML blasts to Venetoclax. Genes involved in mitochondrial organization and function were significantly depleted throughout our screen, including the mitochondrial chaperonin CLPB. We demonstrated that CLPB is upregulated in human AML, it is further induced upon acquisition of Venetoclax resistance and its ablation sensitizes AML cells to Venetoclax. Mechanistically, CLPB maintains the mitochondrial cristae structure via its interaction with the cristae-shaping protein OPA1, whereas its loss promotes apoptosis by inducing cristae remodeling and mitochondrial stress responses. Overall, our data suggest that targeting mitochondrial architecture may provide a promising approach to circumvent Venetoclax resistance.
Project description:Background: Targeting the metabolic dependencies of acute myeloid leukemia (AML) cells is a promising therapeutical strategy. In particular, the cysteine and methionine metabolism pathway (C/M) is significantly altered in AML cells compared to healthy blood cells. Moreover, methionine has been identified as one of the dominant amino acid dependencies of AML cells. Methods: Through RNA-seq, we found that the two nucleoside analogs 8-chloro-adenosine (8CA) and 8-amino-adenosine (8AA) significantly suppress the C/M pathway in AML cells, and methionine-adenosyltransferase-2A (MAT2A) is one of most significantly downregulated genes. Additionally, mass spectrometry analysis revealed that Venetoclax (VEN), a BCL-2 inhibitor recently approved by the FDA for AML treatment, significantly decreases the intracellular level of methionine in AML cells. Based on these findings, we hypothesized that combining 8CA or 8AA with VEN can efficiently target the Methionine-MAT2A-S-adenosyl-methionine (SAM) axis in AML. Results: Our results demonstrate that VEN and 8CA/8AA synergistically decrease the SAM biosynthesis and effectively target AML cells both in vivo and in vitro. Conclusions: These findings suggest the promising potential of combining 8CA/8AA and VEN for AML treatment by inhibiting Methionine-MAT2A-SAM axis and provide a strong rationale for our recently activated clinical trial.
Project description:Purpose: To show that 8-Cl-Ado can target FAO and synergizes with VEN to significantly decrease the oxygen consumption rate (OCR) and in turn OXPHOS in CD34-enriched AML cells. Methods: Using AML cell lines and LSC-enriched blast cells from pre-treatment AML patients, we evaluated the effects of 8-Cl-Ado, VEN and the 8-Cl-Ado/VEN combination on fatty acid metabolism, glycolysis and OXPHOS using liquid scintillation counting, a Seahorse XF Analyzer and gene set enrichment analysis (GSEA). Results: We here report that VEN and 8-Cl-Ado synergistically inhibited in vitro growth of AML cells. Furthermore, immunodeficient mice engrafted with MV4-11-Luc AML cells and treated with the combination of VEN plus 8-Cl-Ado had a significantly longer survival than mice treated with either drugs alone (p≤0.006). Conclusion: Taken together, the results suggest that 8-Cl-Ado enhances the antileukemic activity of VEN and that this combination represents a promising therapeutic regimen for treatment of AML.