Caspase-activated DNase is necessary and sufficient for oligonucleosomal DNA breakdown, but not for chromatin disassembly during caspase-dependent apoptosis of LN-18 glioblastoma cells
Sánchez-Osuna, María (Universitat Autònoma de Barcelona. Institut de Neurociències)
Garcia i Belinchón, Maria Mercè (Universitat Autònoma de Barcelona. Institut de Neurociències)
Iglesias Guimarais, Victoria (Universitat Autònoma de Barcelona. Institut de Neurociències)
Gil Guiñon, Estel (Universitat Autònoma de Barcelona. Institut de Neurociències)
Casanelles Abella, Elisenda (Universitat Autònoma de Barcelona. Institut de Neurociències)
Yuste, Victor J.. (Víctor José) (Universitat Autònoma de Barcelona. Departament de Bioquímica i de Biologia Molecular)

Date:	2014
Abstract:	Caspase-dependent apoptosis is a controlled type of cell death characterized by oligonucleosomal DNA breakdown and major nuclear morphological alterations. Other kinds of cell death do not share these highly distinctive traits because caspase-activated DNase (DFF40/CAD) remains inactive. Here, we report that human glioblastoma multiforme-derived LN-18 cells do not hydrolyze DNA into oligonucleosomal fragments after apoptotic insult. Furthermore, their chromatin remains packaged into a single mass, with no signs of nuclear fragmentation. However, ultrastructural analysis reveals that nuclear disassembly occurs, although compacted chromatin does not localize into apoptotic nuclear bodies. Caspases become properly activated, and ICAD, the inhibitor of DFF40/CAD, is correctly processed. Using cell-free in vitro assays, we show that chromatin from isolated nuclei of LN-18 cells is suitable for hydrolysis into oligonuclesomal fragments by staurosporine-pretreated SH-SY5Y cytoplasms. However, staurosporine-pretreated LN-18 cytoplasms do not induce DNA laddering in isolated nuclei from either LN-18 or SH-SY5Y cells because LN-18 cells express lower amounts of DFF40/CAD. DFF40/CAD overexpression makes LN-18 cells fully competent to degrade their DNA into oligonucleosome-sized fragments, and yet they remain unable to arrange their chromatin into nuclear clumps after apoptotic insult. Indeed, isolated nuclei from LN-18 cells were resistant to undergoing apoptotic nuclear morphology in vitro. The use of LN-18 cells has uncovered a previously unsuspected cellular model, whereby a caspase-dependent chromatin package is DFF40/CAD-independent, and DFF40/CAD-mediated double-strand DNA fragmentation does not warrant the distribution of the chromatin into apoptotic nuclear bodies. The studies highlight a not-yet reported DFF40/CAD-independent mechanism driving conformational nuclear changes during caspase-dependent cell death.
Grants:	Ministerio de Economía y Competitividad SAF2012-31485 Agència de Gestió d'Ajuts Universitaris i de Recerca 2009/SGR-346 Ministerio de Ciencia e Innovación BES-2099-028572 Ministerio de Ciencia e Innovación TRA2009-0185
Note:	Altres ajuts: FPU MICINN, MEC programa Ramón y Cajal
Rights:	Tots els drets reservats.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Apoptosis ; Apoptotic Nuclear Morphology ; Caspase ; Chromatin Disassembly ; DFF40/CAD ; DNA ; Deoxyribonuclease (DNase) ; Nucleus ; Oligonucleosomal DNA fragmentation
Published in:	Journal of biological chemistry, Vol. 289 Núm. 27 (2014) , p. 18752-18760, ISSN 1083-351X

DOI: 10.1074/jbc.M114.550020
PMID: 24838313

18 p, 9.5 MB

The record appears in these collections:
Research literature > UAB research groups literature > Research Centres and Groups (research output) > Health sciences and biosciences > Institut de Neurociències (INc)
Articles > Research articles
Articles > Published articles