title: U937 variant cells as a model of apoptosis without cell disintegration.
abstract: The variant cell line U937V was originally identified by a higher sensitivity to the cytocidal action of tumor necrosis factor alpha (TNFα) than that of its reference cell line, U937. We noticed that a typical morphological feature of dying U937V cells was the lack of cellular disintegration, which contrasts to the formation of apoptotic bodies seen with dying U937 cells. We found that both TNFα, which induces the extrinsic apoptotic pathway, and etoposide (VP-16), which induces the intrinsic apoptotic pathway, stimulated U937V cell death without cell disintegration. In spite of the distinct morphological differences between the U937 and U937V cells, the basic molecular events of apoptosis, such as internucleosomal DNA degradation, phosphatidylserine exposure on the outer leaflet of the plasma membrane, caspase activation and cytochrome c release, were evident in both cell types when stimulated with both types of apoptosis inducer. In the U937V cells, we noted an accelerated release of cytochrome c, an accelerated decrease in mitochondrial membrane potential, and a more pronounced generation of reactive oxygen species compared to the reference cells. We propose that the U937 and U937V cell lines could serve as excellent comparison models for studies on the mechanisms regulating the processes of cellular disintegration during apoptosis, such as blebbing (zeiosis) and apoptotic body formation.
authors.affiliation: Department of Cell Biology, Intercollegiate Faculty of Biotechnology UG-MUG, Medical University of Gdansk, Gdansk, Poland.
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Stasiłojć
authors.forename: Sandra
authors.initials: S
authors.lastname: Pinto
authors.forename: Roksana
authors.initials: R
authors.lastname: Wyszkowska
authors.forename: Magda
authors.initials: M
authors.lastname: Wejda
authors.forename: Ewa M
authors.initials: EM
authors.lastname: Słomińska
authors.forename: Martyna
authors.initials: M
authors.lastname: Filipska
authors.forename: Patrycja
authors.initials: P
authors.lastname: Koszałka
authors.forename: Julian
authors.initials: J
authors.lastname: Swierczyński
authors.forename: Jose Enrique
authors.initials: JE
authors.lastname: O'Connor
authors.forename: Jacek Jerzy
authors.initials: JJ
authors.lastname: Bigda
mesh_terms: D017209:Apoptosis; D015153:Blotting, Western; D053453:Caspase 9 / Q000378:metabolism; D048430:Cell Shape; D045304:Cytochromes c / Q000378:metabolism; D053938:DNA Fragmentation; D004789:Enzyme Activation; D006801:Humans; D016403:Lymphoma, Large B-Cell, Diffuse / Q000473:pathology; D008928:Mitochondria / Q000378:metabolism; D008954:Models, Biological; D015398:Signal Transduction; D020298:U937 Cells
chemical_list: D045304:Cytochromes c; D053453:Caspase 9