Similar Datasets
Project description:Drug-tolerant “persister” cells underlie the emergence of drug-resistant clones and allow residual tumors to survive therapy; thus, represent an attractive therapeutic target to mitigate relapse. With the promising outcome, yet some resistance cases surfaced after the approval of venetoclax (ABT-199), we defined a novel invasive drug resistance mechanism induced by Bcl2 inhibitor via examining the evolution of drug tolerant persister clones generated with ABT-199 treatment. The ABT-199 drug-tolerant persister cells showed genetic alteration by losing the copy number at 18q21 paralleled with BCL2, PMAIP1 and TCF4 gene downregulation. The persister status are generated through major enhancer-remodeling mediated transcriptional activation of the super enhancer, which offered unique opportunity for overcoming the drug resistance. The insight of major determinant for ABT-199 persistence evolution identified the molecular vulnerability in Bcl2 inhibitor resistant lymphoma cells through CDK7 pathway inhibition. The combined CDK7 and BCL2 inhibition was found to be more effective against ABT-199 persistence ex vivo and in vivo rather than the parental line, and CDK7 inhibition eliminated the persister phenotype by blocking dynamic active enhancer formation to further prevent the evolution of drug resistance. Together, these studies unified genetic alteration and non-mutational adaptive response as a drug resistance mechanism, more importantly, demonstrated a rationale for transcriptional inhibition-based combination strategies to prevent and overcome drug resistance in B-cell malignancies.
2019-05-01 | GSE116129 | GEO
Project description:Drug-tolerant “persister” cells underlie the emergence of drug-resistant clones and allow residual tumors to survive therapy; thus, represent an attractive therapeutic target to mitigate relapse. With the promising outcome, yet some resistance cases surfaced after the approval of venetoclax (ABT-199), we defined a novel invasive drug resistance mechanism induced by Bcl2 inhibitor via examining the evolution of drug tolerant persister clones generated with ABT-199 treatment. The ABT-199 drug-tolerant persister cells showed genetic alteration by losing the copy number at 18q21 paralleled with BCL2, PMAIP1 and TCF4 gene downregulation. The persister status are generated through major enhancer-remodeling mediated transcriptional activation of the super enhancer, which offered unique opportunity for overcoming the drug resistance. The insight of major determinant for ABT-199 persistence evolution identified the molecular vulnerability in Bcl2 inhibitor resistant lymphoma cells through CDK7 pathway inhibition. The combined CDK7 and BCL2 inhibition was found to be more effective against ABT-199 persistence ex vivo and in vivo rather than the parental line, and CDK7 inhibition eliminated the persister phenotype by blocking dynamic active enhancer formation to further prevent the evolution of drug resistance. Together, these studies unified genetic alteration and non-mutational adaptive response as a drug resistance mechanism, more importantly, demonstrated a rationale for transcriptional inhibition-based combination strategies to prevent and overcome drug resistance in B-cell malignancies.
2019-05-01 | GSE116097 | GEO
Project description:Chromosomal deletion and chromatin remodeling Drive ABT-199 Resistance in B-cell Lymphomas
| PRJNA477350 | ENA
Project description:Chromosomal deletion and chromatin remodeling Drive ABT-199 Resistance in B-cell Lymphomas [RNA-seq]
| PRJNA477352 | ENA
Project description:Chromosomal deletion and chromatin remodeling Drive ABT-199 Resistance in B-cell Lymphomas [ChIP-seq]
| PRJNA477330 | ENA
Project description:Drug-tolerant “persister” tumor cells underlie the emergence of drug-resistant clones contribute to relapse and disease progression; thus, identifying actionable targets that disable persisters and mitigate relapse are a high priority need. Although the BCL2-targeting agent venetoclax (ABT-199) has shown promising responses in mantle cell and double hit B cell lymphomas, resistance often arises, yet mechanistically how this occurs is unclear. Here we report that ABT-199 resistance can evolve from persister clones that have selective deletions at 18q21 that involve the drug target BCL2 and the apoptotic regulators Noxa (PMAIP1) and TCF4. Notably, reprogramming of super enhancers (SE) in persisters contributes to resistance, where there is a selection for SE-directed overexpression of the apoptotic regulator BCL2A1 and oncogenic transcription factors IKZF1 and FOXC1. At the same time, the SE reprogramming confers an opportunity for overcoming ABT-199 resistance. An unbiased drug screen on a platform that recapitulates the lymphoma microenvironment revealed that persisters are vulnerable to inhibitors of transcription initiation and elongation, and especially so to inhibitors of cyclin-dependent kinase 7 (CDK7) that is essential for transcription initiation. Specifically, CDK7 loss or inhibition eliminated the persister phenotype by disabling SE-driven expression of BCL2A1, IKZF1 and FOXC1. Thus, the co-treatment of ABT-199 with CDK7 inhibitors blocked the evolution of drug resistance, and provoked tumor regression in models of mantle cell lymphoma (MCL) and double hit lymphomas (DHL) that overexpress both MYC and BCL2. Together, these findings establish loss of apoptotic regulators and an adaptive transcriptional response as drug resistance mechanisms in lymphoma, more importantly, establish a rationale for transcription inhibition-based combination strategies to prevent and overcome drug resistance in B cell malignancies toward BCL2 inhibitor.
2020-05-26 | PXD010193 | Pride
Project description:Drug-tolerant "persister" tumor cells underlie emergence of drug-resistant clones and contribute to relapse and disease progression. Here we report that resistance to the BCL-2 targeting drug ABT-199 in models of mantle cell lymphoma and double-hit lymphoma evolves from outgrowth of persister clones displaying loss of 18q21 amplicons that harbor BCL2. Further, persister status is generated via adaptive super-enhancer remodeling that reprograms transcription and offers opportunities for overcoming ABT-199 resistance. Notably, pharmacoproteomic and pharmacogenomic screens revealed that persisters are vulnerable to inhibition of the transcriptional machinery and especially to inhibition of cyclin-dependent kinase 7 (CDK7), which is essential for the transcriptional reprogramming that drives and sustains ABT-199 resistance. Thus, transcription-targeting agents offer new approaches to disable drug resistance in B-cell lymphomas.
| S-EPMC6945775 | biostudies-literature
Project description:Background and purposeAlthough the ongoing clinical trials of ABT-263 and ABT-199 in chronic lymphocytic leukaemia (CLL) have indicated that BH3 mimetics hold considerable promise, understanding the mechanism of CLL resistance to BH3 mimetics remains a challenge.Experimental approachThe LD50 values of ABT-737, ABT-263 and ABT-199 in a number of primary CLL cells from 40 patients, were determined. The levels of Bcl-2 family proteins, including phosphorylated Bcl-2 (pBcl-2) and their interactions were measured by immunoblotting and co-immunoprecipitation. In vitro binding assays were performed by isothermal titration calorimetry and ELISA. BH3 profiling in isolated mitochondria was analysed.Key resultsThe ratio of (Mcl-1 + pBcl-2) to Bcl-2 expression provided the most significant predictive marker for the cytotoxic potential of ABT-737, ABT-263 and ABT-199 in the panel of CLL samples. Mechanistically, pBcl-2 inhibited the effects of the ABT compounds on the displacement of Bax and Bim from Bcl-2, thereby suppressing mitochondrial apoptosis. The ABT compounds exhibited 100-300-fold lower binding affinity to the glutamic acid, phosphomimetic, mutant of Bcl-2 (T69E, S70E and S87E; EEE-Bcl-2). BH3 peptides exhibited different rank orders of binding affinities to full-length WT-Bcl-2 and full-length EEE-Bcl-2.Conclusions and implicationsOur study suggested that a structural alteration in the BH3-binding groove was induced by phosphorylation of Bcl-2. Our data also provided a framework to overcome resistance of CLL cells to the ABT compounds by combining pBcl-2 kinase inhibitors with the ABT compounds.
| S-EPMC4728412 | biostudies-literature
Project description:BH3-only proteins trigger the stress apoptosis pathway and chemical mimetics have great potential for cancer therapy. BH3-only proteins inhibit antiapoptotic members of the Bcl-2 family. Promising BH3 mimetic ABT-737 and the related orally available compound ABT-263 (navitoclax) bind avidly to antiapoptotic Bcl-2, Bcl-xL, and Bcl-w. However, their interaction with Bcl-xL provokes thrombocytopenia, which has proven to be the dose-limiting toxicity. We have tested the efficacy of ABT-199, a new Bcl-2-specific BH3 mimetic, against aggressive progenitor cell lymphomas derived from bitransgenic myc/bcl-2 mice. As a single agent, ABT-199 was as effective as ABT-737 in prolonging survival of immunocompetent tumor-bearing mice without causing thrombocytopenia. Both drugs acted rapidly but, contrary to prevailing models, their apoptotic activity did not rely upon the BH3-only protein Bim. When ABT-737 was combined with the proteosome inhibitor bortezomib or CDK inhibitor purvalanol, many treated animals achieved long-term remission.
| S-EPMC3606065 | biostudies-literature
Project description:ABT-199, a potent and selective small-molecule antagonist of BCL-2, is being clinically vetted as pharmacotherapy for the treatment of acute myeloid leukemia (AML). However, given that prolonged monotherapy tends to beget resistance, we sought to investigate the means by which resistance to ABT-199 might arise in AML and the extent to which those mechanisms might be preempted. Here we used a pathway-activating genetic screen to nominate MCL-1 and BCL-XL as potential nodes of resistance. We then characterized a panel of ABT-199-resistant myeloid leukemia cell lines derived through chronic exposure to ABT-199 and found that acquired drug resistance is indeed driven by the upregulation of MCL-1 and BCL-XL. By targeting MCL-1 and BCL-XL, resistant AML cell lines could be resensitized to ABT-199. Further, preemptively targeting MCL-1 and/or BCL-XL alongside administration of ABT-199 was capable of delaying or forestalling the acquisition of drug resistance. Collectively, these data suggest that in AML, (1) the selection of initial therapy dynamically templates the landscape of acquired resistance via modulation of MCL-1/BCL-XL and (2) appropriate selection of initial therapy may delay or altogether forestall the acquisition of resistance to ABT-199.
| S-EPMC4901329 | biostudies-literature