The TP53 Apoptotic Network is a Primary Mediator of Resistance to BCL2 inhibition in AML Cells
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ABSTRACT:
PROVIDER: PRJNA540210 | ENA |
REPOSITORIES: ENA
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Project description:To study mechanisms underlying resistance to the BCL2 inhibitor venetoclax in acute myeloid leukemia (AML), we used a genome-wide CRISPR/Cas9 screen to identify gene knockouts resulting in drug resistance. We validated TP53, BAX, and PMAIP1 as genes whose inactivation results in venetoclax resistance in AML cell lines. Resistance to venetoclax resulted from an inability to execute apoptosis driven by BAX loss, decreased expression of BCL2, and/or reliance on alternative BCL2 family members such as BCL2L1. The resistance was accompanied by changes in mitochondrial homeostasis and cellular metabolism. Evaluation of TP53 knockout cells for sensitivities to a panel of small-molecule inhibitors revealed a gain of sensitivity to TRK inhibitors. We relate these observations to patient drug responses and gene expression in the Beat AML dataset. Our results implicate TP53, the apoptotic network, and mitochondrial functionality as drivers of venetoclax response in AML and suggest strategies to overcome resistance. SIGNIFICANCE: AML is challenging to treat due to its heterogeneity, and single-agent therapies have universally failed, prompting a need for innovative drug combinations. We used a genetic approach to identify genes whose inactivation contributes to drug resistance as a means of forming preferred drug combinations to improve AML treatment.See related commentary by Savona and Rathmell, p. 831.This article is highlighted in the In This Issue feature, p. 813.
| S-EPMC6606338 | biostudies-literature
Project description:We established BFSigs labeled as the BCL2, MCL1/BCL2, and BFL1/MCL1 signatures that identify key anti-apoptotic proteins. Unsupervised clustering based on BFSig information consistently classified AML patients into three robust subtypes across different AML cohorts, implying the existence of biological entities revealed by the BFSig approach. Lastly, we successfully confirmed the validity of BFSigs using NanoString technology.
2022-07-27 | GSE209822 | GEO
Project description:This SuperSeries is composed of the SubSeries listed below.
2019-04-30 | GSE130414 | GEO
Project description:AMPK activation enhances apoptotic priming and BCL2 dependence via PERK phosphorylation
| PRJNA623197 | ENA
Project description:TP53-mutant acute myeloid leukemia (AML) and myelodysplastic neoplasms (MDS) are characterized by chemotherapy resistance and represent an unmet clinical need. Chimeric antigen receptor (CAR) T-cell therapy might be a promising therapeutic option for TP53-mutant AML/MDS. However, the impact of TP53 deficiency in AML cells on the efficacy of CAR T-cells is unknown. We here show that CAR T-cells engaging TP53-deficient leukemia cells exhibit a prolonged interaction time, upregulate exhaustion markers, and are unable to control AML cell outgrowth in vitro and in vivo compared to TP53 wildtype cells. Transcriptional profiling revealed that the mevalonate pathway is upregulated in TP53-deficient AML cells under CAR T-cell attack, while CAR T-cells engaging TP53-deficient AML cells downregulate the Wnt pathway. In vitro rational targeting of either of these pathways rescues AML cell sensitivity to CAR T-cell-mediated killing. We thus demonstrate that TP53 deficiency confers resistance to CAR T-cell therapy and identify the mevalonate pathway as a therapeutic vulnerability of TP53-deficient AML cells engaged by CAR T-cells, and the Wnt pathway as a promising CAR T-cell therapy-enhancing approach for TP53-deficient AML/MDS.
2023-10-31 | GSE246335 | GEO
Project description:Activation of the MYC oncogene is common in B-cell lymphomas, and frequently associated with compensatory events that dampen Myc-induced apoptosis, such as over-expression of anti-apoptotic Bcl2-family proteins. For example, concurrent translocations of MYC and BCL2 in a subset of Diffuse large B-cell lymphoma (DLBCL) lead to the high-grade “double-hit” lymphoma subtype (DHL), characterized by dismal prognosis in the face of current front-line regimens, thus calling for the pursuit of tailored therapeutic strategies. Here, we show that Myc and Bcl2 modulate the sensitivity of B-cells to IACS-010759, a selective inhibitor of mitochondrial respiratory complex I. Myc activation in non-transformed lymphoid precursors suppressed endogenous Bcl2 and sensitized the cells to IACS-010759-induced apoptosis. Treatment with the Bcl2 inhibitor venetoclax also sensitized to IACS-010759, while overexpression of Bcl-2 was protective. IACS-010759 engaged an ATF4-driven Integrated Stress Response (ISR) with dual anti- and pro-apoptotic effects, the latter mediated by the CHOP transcription factor, which contributed to selective killing of Myc-overexpressing cells. In line with the above data, IACS-010759 and venetoclax synergized in killing human DHL cells, and showed strong combinatorial effects in a pre-clinical setting. In a Bcl2-negative Burkitt’s lymphoma cell line, instead, IACS-010759 synergized with the Mcl-1 inhibitor S63845. Altogether, our data point to the combination of IACS-010759 with distinct Bcl2-family inhibitors for therapeutic reactivation of the intrinsic apoptotic pathway in Myc-associated B-cell lymphomas
2022-03-01 | GSE149073 | GEO
Project description:Super-enhancers (SEs), which are composed of large clusters of enhancers densely loaded with the Mediator complex, transcription factors and chromatin regulators, drive high expression of genes implicated in cell identity and disease, such as lineage-controlling transcription factors and oncogenes. BRD4 and CDK7 are positive regulators of SE-mediated transcription. By contrast, negative regulators of SE-associated genes have not been well described. Here we show that the Mediator-associated kinases cyclin-dependent kinase 8 (CDK8) and CDK19 restrain increased activation of key SE-associated genes in acute myeloid leukaemia (AML) cells. We report that the natural product cortistatin A (CA) selectively inhibits Mediator kinases, has anti-leukaemic activity in vitro and in vivo, and disproportionately induces upregulation of SE-associated genes in CA-sensitive AML cell lines but not in CA-insensitive cell lines. In AML cells, CA upregulated SE-associated genes with tumour suppressor and lineage-controlling functions, including the transcription factors CEBPA, IRF8, IRF1 and ETV6. The BRD4 inhibitor I-BET151 downregulated these SE-associated genes, yet also has anti-leukaemic activity. Individually increasing or decreasing the expression of these transcription factors suppressed AML cell growth, providing evidence that leukaemia cells are sensitive to the dosage of SE-associated genes. Our results demonstrate that Mediator kinases can negatively regulate SE-associated gene expression in specific cell types, and can be pharmacologically targeted as a therapeutic approach to AML. This SuperSeries is composed of the SubSeries listed below.
2015-09-25 | GSE65161 | GEO
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.
2021-11-12 | GSE183329 | GEO
Project description:Expression of proteins regulating apoptosis (BCL-2, MCL-1, BCL-X and BAX) in acute myeloid leukemia (AML) blasts at diagnosis have been shown to be associated with disease-free survival. The concentrations of these proteins are combined in the Anti Apoptotic index (AAI). We previously found that the initially high apoptosis-resistance of AML cells decreased after therapy, while regaining high levels at relapse. This suggested a dynamic regulation of apoptosis. We hypothesized that expression of apoptosis-related proteins in AML blasts, and possibly also in bystander cells in the bone marrow, is regulated by extracellular factors present in the AML microenvironment. Tumor cell communication with its microenvironment is emerging as an important determinant playing multiple roles in cancer. Both soluble factors and extracellular vesicles (EVs), most notably exosomes, have been shown to influence cellular processes of malignant and normal cells in the tumor microenvironment. We performed a proteomics analysis of the whole secretome as well as of EVs secreted by AML blasts to pinpoint released protein factors that might mediate apoptosis-resistance.
2016-10-21 | MSV000080266 | MassIVE
Project description:Therapy resistance is a major challenge in the treatment of cancer. Here, we performed CRISPR/Cas9 screens across a broad range of therapies used in acute myeloid leukemia (AML) to identify genomic determinants of drug response. Our screens uncovered a selective dependency on RNA splicing factors whose loss preferentially synergized with the BCL2 inhibitor venetoclax. Loss of the splicing factor RBM10 augmented response to venetoclax in leukemia yet was completely dispensable for normal hematopoiesis. Combined RBM10 and BCL2 inhibition led to mis-splicing and inactivation of the inhibitor of apoptosis XIAP and downregulation of BCL2A1, an anti-apoptotic protein implicated in venetoclax resistance. A novel inhibitor of splicing kinase families CLKs and DYRKs led to intron retention of key splicing factors identified from our screens, synergized with venetoclax, and overcame resistance to BCL2 inhibition. Our findings underscore the central importance of splicing in modulating apoptosis and provide a strategy to improve venetoclax-based treatments.
2022-10-31 | GSE199160 | GEO