title: Two different pathways for necrotic cell death induced by free radicals.
abstract: Plasma membrane modifications have been widely recognized as crucial factors in cell injury and death. One of these modifications, surface blebbing, has been considered as an injury-marker associated with a series of biochemical and physiological modifications. Our study focused on the different effects of free radical-induced cell damage by quinone menadione (2-methyl-1,4-naphthoquinone) and by hyperthermic shock (45 degrees C) on the erythroleukemic cell line K562. Different techniques including immunofluorescence, freeze-fracturing, and electron paramagnetic resonance spectroscopy were employed. Menadione induced the formation of surface blebs, accompanied by a rearrangement of the microfilament system and changes in the distribution of plasma membrane proteins. In contrast, heat-shocked cells showed neither blebbing nor important cytoskeletal changes. Finally, the electron paramagnetic resonance results showed an increase in membrane order not specifically related to the type of free radical-induced stress. These cell death features appear to suggest the existence of two different types of pathways for necrotic cell death: both treatments induce cell injury and eventual death by modifying plasma membrane integrity and function. However, one involves cytoskeleton-dependent surface blebbing, whereas the other does not.
authors.affiliation: Department of Ultrastructures, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: W
authors.initials: W
authors.lastname: Malorni
authors.forename: S
authors.initials: S
authors.lastname: Paradisi
authors.forename: F
authors.initials: F
authors.lastname: Iosi
authors.forename: M T
authors.initials: MT
authors.lastname: Santini
mesh_terms: D016923:Cell Death / Q000187:drug effects / Q000502:physiology; D048429:Cell Size / Q000187:drug effects / Q000502:physiology; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals / Q000378:metabolism*; D005614:Freeze Fracturing; D006358:Hot Temperature; D008855:Microscopy, Electron, Scanning; D008856:Microscopy, Fluorescence; D009336:Necrosis / Q000139:chemically induced / Q000209:etiology* / Q000378:metabolism; D014407:Tumor Cells, Cultured; D014812:Vitamin K / Q000633:toxicity
chemical_list: D005609:Free Radicals; D014812:Vitamin K