Dataset Information

AMP-Activated Protein Kinase Contributes to Apoptosis Induced by the Bcl-2 Inhibitor Venetoclax in Acute Myeloid Leukemia.

ABSTRACT: The treatment of acute myeloid leukemia (AML) remains a challenge especially among the elderly. The Bcl-2 inhibitor venetoclax recently showed significant survival benefits in AML patients when combined to low-dose cytarabine or azacitidine. Bcl-2 inhibition initiate mitochondrial apoptosis, but also respiration and cellular ATP production in AML. AMP-Activated Protein Kinase (AMPK) is a central energy sensor activated by increased AMP:ATP ratio to restore the cellular energy balance. Unexpectedly, we observed that venetoclax inhibited AMPK activity through caspase-dependent degradation of AMPK subunits in AML cells. On the other hand, genetic models of AMPK invalidation and re-expression suggested that AMPK participated to the early stages of apoptotic response through a negative regulation of multi-domain anti-apoptotic effectors such as Mcl-1 or Bcl-xL. Together our results suggested a new link between AMPK and Bcl-2-dependent mitochondrial apoptosis that participated to the anti-leukemic activity of venetoclax in AML.

SUBMITTER: Legrand N

PROVIDER: S-EPMC8656606 | biostudies-literature | 2021 Nov

REPOSITORIES: biostudies-literature

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AMP-Activated Protein Kinase Contributes to Apoptosis Induced by the Bcl-2 Inhibitor Venetoclax in Acute Myeloid Leukemia.

Legrand Noémie N Pradier Amandine A Poulain Laury L Mouche Sarah S Birsen Rudy R Larrue Clément C Simonetta Federico F Tamburini Jerome J

Cancers 20211127 23

The treatment of acute myeloid leukemia (AML) remains a challenge especially among the elderly. The Bcl-2 inhibitor venetoclax recently showed significant survival benefits in AML patients when combined to low-dose cytarabine or azacitidine. Bcl-2 inhibition initiate mitochondrial apoptosis, but also respiration and cellular ATP production in AML. AMP-Activated Protein Kinase (AMPK) is a central energy sensor activated by increased AMP:ATP ratio to restore the cellular energy balance. Unexpected ...[more]

PMID: 34885077

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Project description:IntroductionThe emergence of resistance to the highly successful BCL2-directed therapy is a major unmet need in acute myeloid leukemia (AML), an aggressive malignancy with poor survival rates. Towards identifying therapeutic options for AML patients who progress on BCL2-directed therapy, we studied a clinical-stage CDK7 inhibitor XL102, which is being evaluated in solid tumors (NCT04726332).Materials and methodsTo determine the anti-proliferative effects of XL102, we performed experiments including time-resolved fluorescence resonance energy transfer, target occupancy, cell cycle and apoptosis-based assays. We also included genetically characterized primary myeloid blasts from de novo and relapsed/refractory AML patients. For mechanistic studies, CRISPR/Cas9 mediated knockout of CDK7 and c-Myc and immunoblotting were performed. NOD/SCID orthotropic and subcutaneous AML xenografts were used to determine anti-leukemic effects. To assess the synergistic effects of XL102 with Venetoclax, we performed RNA sequencing and gene set enrichment analysis using Venetoclax sensitive and resistant model systems.ResultsXL102, a highly specific, orally bioavailable covalent inhibitor of CDK7. Inhibitory effect on CDK7 by XL102 in primary myeloid blasts (n = 54) was in nanomolar range (mean = 300 nM; range = 4.0-952 nM). XL102 treated AML cells showed a reduction in phosphorylation levels of Serine 2/5/7 at carboxy-terminal domain of RNA polymerase II. T-loop phosphorylation of CDK1(Thr161) and CDK2(Thr160) was inhibited by XL102 in dose-dependent manner leading to cell-cycle arrest. c-Myc downregulation and enhanced levels of p53 and p21 in XL102 treated cells were observed. Increased levels of p21 and activation of p53 by XL102 were mimicked by genetic ablation of CDK7, which supports that the observed effects of XL102 are due to CDK7 inhibition. XL102 treated AML xenografts showed remarkable reduction in hCD45 + marrow cells (mean = 0.60%; range = 0.04%-3.53%) compared to vehicle control (mean = 38.2%; range = 10.1%-78%), with corresponding increase in p53, p21 and decrease in c-Myc levels. The data suggests XL102 induces apoptosis in AML cells via CDK7/c-Myc/p53 axis. RNA-sequencing from paired Venetoclax-sensitive and Venetoclax-resistant cells treated with XL102 showed downregulation of genes involved in proliferation and apoptosis.ConclusionTaken together, XL102 with Venetoclax led to synergistic effects in overcoming resistance and provided a strong rationale for clinical evaluation of XL102 as a single agent and in combination with Venetoclax.

Project description:BackgroundVenetoclax (VTX) is an anticancer drug. It is a selective Bcl-2 inhibitor that is clinically used for the treatment of patients with lymphomas and leukemias. Treatment with VTX, however, is accompanied by severe adverse events such as tumor lysis syndrome and neutropenia, because VTX readily binds to serum proteins, which results in poor pharmacokinetics and poor tumor tissue concentration. To avoid such adverse events, VTX is administered using a daily or weekly ramp-up schedule that is cumbersome in clinical situations.AimsTo overcome these shortcomings, we prepared a novel polyethylene glycol (PEG)-drug conjugate of VTX (PEG-VTX) and evaluated its cytotoxic effects on acute myeloid leukemia (AML) both in vitro and in vivo.Methods and resultsVTX and 4-armed PEG derivatives were covalently attached through an amide bond linker. In a series of in vitro studies, PEG-VTX selectively induced potent growth inhibition of MV4-11 human AML cells via the inducement of Bcl-2-mediated apoptosis. PEG-VTX had the effect of free VTX, presumably due to the protease-mediated release of VTX from the conjugates. In in vivo studies with AML tumor-xenograft mice models, intravenous PEG-VTX promoted sufficient tumor growth suppression. Compared with a regimen of oral free VTX, the intravenous regimen in those studies used a VTX dosage that was 15-30 times smaller for an OCI-AML-2 xenograft model and a dosing regimen that was less frequent for an MV4-11 xenograft model. The most important development, however, was the absence of weight loss related to severe side effects throughout the treatments. An increase in water solubility and the resultant hydrodynamic size of VTX via PEGylation improved the pharmacokinetics of VTX by avoiding protein interactions and lessening the extravasation from blood. The result was an increase in tumor accumulation and a decrease in the nonspecific distribution of VTX.ConclusionThe results of this study suggest that PEG-VTX could be an alternative therapeutic option for the safe and effective treatment of patients with AML.

Dataset Information

AMP-Activated Protein Kinase Contributes to Apoptosis Induced by the Bcl-2 Inhibitor Venetoclax in Acute Myeloid Leukemia.

Publications

AMP-Activated Protein Kinase Contributes to Apoptosis Induced by the Bcl-2 Inhibitor Venetoclax in Acute Myeloid Leukemia.

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