Similar Datasets
Project description:The drug efflux pump ABCB1 (ATP binding cassette subfamily B member 1) confers chemotherapy resistance in acute myeloid leukemia (AML). We recently identified an ABCB1 enhancer that is activated in response to a range of cellular stressors, including anthracycline chemotherapy. Stress drives increased ABCB1 expression and allows leukemia cells to escape from targeted third-generation ABCB1 inhibition.
| S-EPMC7051134 | biostudies-literature
Project description:The drug efflux pump ABCB1 is a key driver of chemoresistance, and high expression predicts treatment failure in acute myeloid leukemia (AML). In this study, we identified and functionally validated the network of enhancers that controls expression of ABCB1. We show that exposure of leukemia cells to daunorubicin activated an integrated stress response-like transcriptional program to induce ABCB1 through remodeling and activation of an ATF4-bound, stress-responsive enhancer. Protracted stress primed enhancers for rapid increases in activity following re-exposure of cells to daunorubicin, providing an epigenetic memory of prior drug treatment. In primary human AML, exposure of fresh blast cells to daunorubicin activated the stress-responsive enhancer and led to dose-dependent induction of ABCB1. Dynamic induction of ABCB1 by diverse stressors, including chemotherapy, facilitated escape of leukemia cells from targeted third-generation ABCB1 inhibition, providing an explanation for the failure of ABCB1 inhibitors in clinical trials. Stress-induced upregulation of ABCB1 was mitigated by combined use of the pharmacologic inhibitors U0126 and ISRIB, which inhibit stress signaling and have potential for use as adjuvants to enhance the activity of ABCB1 inhibitors.
| S-EPMC7269587 | biostudies-literature
Project description:The drug efflux pump ABCB1 is a key driver of chemoresistance, and high expression predicts for treatment failure in acute myeloid leukemia (AML). We show that both acute and chronic exposure of leukemia cells to daunorubicin activates an integrated stress response-like transcriptional program to induce ABCB1 through remodeling and dynamic activation of an ATF4-bound, stress-responsive enhancer. In primary human AML, stress-responsive ABCB1 enhancers are accessible and acetylated, and exposure of fresh blast cells to daunorubicin induces ABCB1 in a dose-dependent manner. Dynamic induction of ABCB1 by diverse stressors, including chemotherapy, facilitates escape of leukemia cells from targeted third-generation ABCB1 inhibition. Stress-induced up regulation of ABCB1 is mitigated by combined use of pharmacologic inhibitors U0126 and ISRIB, which inhibit stress signaling.
2020-02-03 | GSE131824 | GEO
Project description:The drug efflux pump ABCB1 is a key driver of chemoresistance, and high expression predicts for treatment failure in acute myeloid leukemia (AML). We show that both acute and chronic exposure of leukemia cells to daunorubicin activates an integrated stress response-like transcriptional program to induce ABCB1 through remodeling and dynamic activation of an ATF4-bound, stress-responsive enhancer. In primary human AML, stress-responsive ABCB1 enhancers are accessible and acetylated, and exposure of fresh blast cells to daunorubicin induces ABCB1 in a dose-dependent manner. Dynamic induction of ABCB1 by diverse stressors, including chemotherapy, facilitates escape of leukemia cells from targeted third-generation ABCB1 inhibition. Stress-induced up regulation of ABCB1 is mitigated by combined use of pharmacologic inhibitors U0126 and ISRIB, which inhibit stress signaling.
2020-02-03 | GSE131823 | GEO
Project description:Dynamic induction of drug resistance through a stress-responsive enhancer in acute myeloid leukemia
| PRJNA545085 | ENA
Project description:Dynamic induction of drug resistance through a stress-responsive enhancer in acute myeloid leukemia [CHIP-seq]
| PRJNA545089 | ENA
Project description:Dynamic induction of drug resistance through a stress-responsive enhancer in acute myeloid leukemia [RNA-seq]
| PRJNA545090 | ENA
Project description:Non-genetic drug resistance is increasingly recognised in various cancers. Molecular insights into this process are lacking and it is unknown whether stable non-genetic resistance can be overcome. Using single cell RNA-sequencing of paired drug naïve and resistant AML patient samples and cellular barcoding in a unique mouse model of non-genetic resistance, here we demonstrate that transcriptional plasticity drives stable epigenetic resistance. With a CRISPR-Cas9 screen we identify regulators of enhancer function as important modulators of the resistant cell state. We show that inhibition of Lsd1 (Kdm1a) is able to overcome stable epigenetic resistance by facilitating the binding of the pioneer factor, Pu.1 and cofactor, Irf8, to nucleate new enhancers that regulate the expression of key survival genes. This enhancer switching results in the re-distribution of transcriptional co-activators, including Brd4, and provides the opportunity to disable their activity and overcome epigenetic resistance. Together these findings highlight key principles to help counteract non-genetic drug resistance.
| S-EPMC6586637 | biostudies-literature
Project description:Acute myeloid leukemia (AML) is an aggressive hematologic neoplasm resulting from the malignant transformation of myeloid progenitors. Despite intensive chemotherapy leading to initial treatment responses, relapse caused by intrinsic or acquired drug resistance represents a major challenge. Here, we report that histone 3 lysine 27 demethylase KDM6A (UTX) is targeted by inactivating mutations and mutation-independent regulation in relapsed AML. Analyses of matched diagnosis and relapse specimens from individuals with KDM6A mutations showed an outgrowth of the KDM6A mutated tumor population at relapse. KDM6A expression is heterogeneously regulated and relapse-specific loss of KDM6A was observed in 45.7% of CN-AML patients. KDM6A-null myeloid leukemia cells were more resistant to treatment with the chemotherapeutic agents cytarabine (AraC) and daunorubicin. Inducible re-expression of KDM6A in KDM6A-null cell lines suppressed proliferation and sensitized cells again to AraC treatment. RNA expression analysis and functional studies revealed that resistance to AraC was conferred by downregulation of the nucleoside membrane transporter ENT1 (SLC29A1) by reduced H3K27 acetylation at the ENT1 locus. Our results show that loss of KDM6A provides cells with a selective advantage during chemotherapy, which ultimately leads to the observed outgrowth of clones with KDM6A mutations or reduced KDM6A expression at relapse.
| S-EPMC7214274 | biostudies-literature
Project description:In addition to spliceosome gene mutations, oncogene expression and drug resistance in AML might influence exon expression. We performed exon-array analysis and exon-specific PCR (ESPCR) to identify specific landscapes of exon expression that are associated with DEK and WT1 oncogene expression and the resistance of AML cells to AraC, doxorubicin or azacitidine. Data were obtained for these five conditions through exon-array analysis of 17 cell lines and 24 patient samples and were extended through qESPCR of samples from 152 additional AML cases. More than 70% of AEUs identified by exon-array were technically validated through ESPCR. In vitro, 1,130 to 5,868 exon events distinguished the 5 conditions from their respective controls while in vivo 6,560 and 9,378 events distinguished chemosensitive and chemoresistant AML, respectively, from normal bone marrow. Whatever the cause of this effect, 30 to 80% of mis-spliced mRNAs involved genes unmodified at the whole transcriptional level. These AEUs unmasked new functional pathways that are distinct from those generated by transcriptional deregulation. These results also identified new putative pathways that could help increase the understanding of the effects mediated by DEK or WT1, which may allow the targeting of these pathways to prevent resistance of AML cells to chemotherapeutic agents.
| S-EPMC4823079 | biostudies-other