Early redistribution of plasma membrane phosphatidylserine is a general feature of apoptosis regardless of the initiating stimulus: inhibition by overexpression of Bcl-2 and Abl.

Abstract

SummaryA critical event during programmed cell death (PCD) appears to be the acquisition of plasma membrane (PM) changes that allows phagocytes to recognize and engulf these cells before they rupture. The majority of PCD seen in higher organisms exhibits strikingly similar morphological features, and this form of PCD has been termed apoptosis. The nature of the PM changes that occur on apoptotic cells remains poorly defined. In this study, we have used a phosphatidylserine (PS)-binding protein (annexin V) as a specific probe to detect redistribution of this phospholipid, which is normally confined to the inner PM leaflet, during apoptosis. Here we show that PS externalization is an early and widespread event during apoptosis of a variety of murine and human cell types, regardless of the initiating stimulus, and precedes several other events normally associated with this mode of cell death. We also report that, under conditions in which the morphological features ofapoptosis were prevented (macromolecular synthesis inhibition, overexpression of Bcl-2 or Abl), the appearance of PS on the external leaflet of the PM was similarly prevented. These data are compatible with the notion that activation of an inside-outside PS translocase is an early and widespread event during apoptosis.

All-trans retinoic acid (ATRA)-induced apoptosis is preceded by G1 arrest in human MCF-7 breast cancer cells

“…In early stages of apoptosis, dramatic changes in the organization of plasma membrane take place, among which is the translocation of phosphatidylserine (PS) residues (which, in non-apoptotic cells, lay in the inner phospholipidic leaflet) to the outer surface of apoptotic cells (Martin et al, 1995). Relatively early apoptotic MCF-7 cells therefore become positive for Annexin V, while being negative for PI, which is excluded from the cells; this was apparent in fluorescent and phase-contrast microscopy (data not shown).…”

Multimodal immunogenic cancer cell death as a consequence of anticancer cytotoxic treatments

“…2,47 In general, CRT exposure during ICD is an earlier process occurring within a few hours than PS externalization. 48 The ecto-CRT induction capacity of ICD inducers has been shown to depend on the properties of ER stress and ROS production. 2,37,49 Cancer cells can induce ecto-CRT followed by disturbance of the ER structure with GADD34 activation and PERK phosphorylation.…”

In vitro measurement of cell death with the annexin A5 affinity assay

“…However, it has become evident that most forms of cell death share the phenomenon of cell surface expression of PS 6 . Externalization of PS is an early event in the sequence of steps leading to cell death; it starts well before the plasma membrane integrity is compromised 7 . PS is therefore a likely ligand for target-specific measurement of cell death.…”

“…Fragmentation of DNA occurs in the late stages of cell death, after PS expression has started 7 . This method consists of many steps and is consequently time consuming.…”