Open AccessKinetics of apoptotic markers in exogeneously induced apoptosis of EL4 cells
Author(s) -
Jessel Robert,
Haertel Steffen,
Socaciu Carmen,
Tykhonova Svetlana,
Diehl Horst A.
Publication year - 2002
Publication title -
journal of cellular and molecular medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.44
H-Index - 130
eISSN - 1582-4934
pISSN - 1582-1838
DOI - 10.1111/j.1582-4934.2002.tb00313.x
Subject(s) - apoptosis , annexin a5 , dna fragmentation , staurosporine , phosphatidylserine , annexin , propidium iodide , fragmentation (computing) , biology , microbiology and biotechnology , membrane fluidity , inducer , biophysics , programmed cell death , phospholipid , biochemistry , membrane , signal transduction , ecology , protein kinase c , gene
We investigated the time‐dependence of apoptotic events in EL4 cells by monitoring plasma membrane changes in correlation to DNA fragmentation and cell shrinkage. We applied three apoptosis inducers (staurosporine, tubericidine and X‐rays) and we looked at various markers to follow the early‐to‐late apoptotic events: phospholipid translocation (identified through annexin V‐fluorescein assay and propidium iodide), lipid package (via merocyanine assay), membrane fluidity and anisotropy (via fluorescent measurements), DNA fragmentation by the fluorescence‐labeling test and cell size measurements. The different apoptotic inducers caused different reactions of the cells: staurosporine induced apoptosis most rapidly in a high number of cells, tubercidine triggered apoptosis only in the S phase cells, while X‐rays caused a G2/M arrest and subsequently apoptosis. Loss of lipid asymmetry is promptly detectable after one hour of incubation time. The phosphatidylserine translocation, decrease of lipid package and anisotropy, and the increase of membrane fluidity appeared to be based on the same process of lipid asymmetry loss. Therefore, the DNA fragmentation and the cell shrinkage appear to be parallel and independent processes running on different time scales but which are kinetically inter‐related. The results indicate different signal steps to apoptosis dependent on inducer characteristics but the kinetics of “early‐to‐late” apoptosis appears to be a fixed program.