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Blood. 2015 May 7;125(19):2948-57. doi: 10.1182/blood-2014-07-586511. Epub 2015 Feb 10.

miRs-138 and -424 control palmitoylation-dependent CD95-mediated cell death by targeting acyl protein thioesterases 1 and 2 in CLL.

Author information

1
Department I of Internal Medicine and Center of Integrated Oncology, University Hospital of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Cologne, Germany;
2
Department of Chemical Biology, Max Planck Institute for Molecular Physiology, Dortmund, Germany;
3
Department of Chemistry and Chemical Biology, Technical University Dortmund, Dortmund, Germany;
4
Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Cologne, Germany;
5
Department of Chemical Biology, Max Planck Institute for Molecular Physiology, Dortmund, Germany; Department of Chemistry and Chemical Biology, Technical University Dortmund, Dortmund, Germany;
6
Department of Chemistry and Chemical Biology, Technical University Dortmund, Dortmund, Germany; Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, Dortmund, Germany; and.
7
Department I of Internal Medicine and Center of Integrated Oncology, University Hospital of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Cologne, Germany; Department I of Internal Medicine, Klinikum Schwabing, Munich, Germany.

Abstract

Resistance toward CD95-mediated apoptosis is a hallmark of many different malignancies, as it is known from primary chronic lymphocytic leukemia (CLL) cells. Previously, we could show that miR-138 and -424 are downregulated in CLL cells. Here, we identified 2 new target genes, namely acyl protein thioesterase (APT) 1 and 2, which are under control of both miRs and thereby significantly overexpressed in CLL cells. APTs are the only enzymes known to promote depalmitoylation. Indeed, membrane proteins are significantly less palmitoylated in CLL cells compared with normal B cells. We identified APTs to directly interact with CD95 to promote depalmitoylation, thus impairing apoptosis mediated through CD95. Specific inhibition of APTs by siRNAs, treatment with miRs-138/-424, and pharmacologic approaches restore CD95-mediated apoptosis in CLL cells and other cancer cells, pointing to an important regulatory role of APTs in CD95 apoptosis. The identification of the depalmitoylation reaction of CD95 by APTs as a microRNA (miRNA) target provides a novel molecular mechanism for how malignant cells escape from CD95-mediated apoptosis. Here, we introduce palmitoylation as a novel posttranslational modification in CLL, which might impact on localization, mobility, and function of molecules, survival signaling, and migration.

PMID:
25670628
PMCID:
PMC4654424
DOI:
10.1182/blood-2014-07-586511
[Indexed for MEDLINE]
Free PMC Article

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