Cell culture density dependent toxicity and chromatin changes upon cadmium treatment in murine pre-B-cells

Abstract

Murine pre-B-cells grown in the presence of lower (1 microM) or higher (5 microM) concentration of cadmium chloride were separated into 13 fractions by centrifugal elutriation. The rate of DNA synthesis after cadmium treatment determined in permeable cells was dependent on cell culture density during cadmium treatment. Cell cycle analysis revealed a shift in the profile of DNA synthesis from replicative to repair DNA synthesis upon cadmium treatment. The study of the relationship between cell culture density and cell diameter at lower and higher cell densities in the presence of 1 microM cadmium chloride concentration showed that a. at 5 x 10(5) cell/ml or lower densities cells were shrinking indicating apoptotic changes, b. at higher cell culture densities the average cell size increased, c. the treatment of cells with low CdCl(2) concentration (1 microM) at higher cell culture density (>5 x 10(5) cell/ml) did not change significantly the average cell diameter. At 5 microM cadmium concentration and higher cell culture densities (>5 x 10(5) cell/ml) the average cell size decreased in each elutriated fraction. Most significant inhibition of cell growth took place in early S phase (2.0-2.5 C value). Apoptotic chromatin changes in chromatin structure after cadmium treatment were seen as large extensive disruptions, holes in the nuclear membrane and stickiness of incompletely folded chromosomes.

Preapoptotic chromatin changes induced by ultraviolet B irradiation in human erythroleukemia K562 cells

“…Since the potential to distinguish among different chromatotoxic effects is of diagnostic significance, we have started to determine and systematize the effects of cadmium treatment [12], gamma irradiation [13]. Genotoxic treatments may have multiple effects on different cell lines, therefore we have used two cell lines (Chinese hamster ovary cells and murine preB cells) for cadmium treatment and have seen the same large extensive disruptions and holes in the nuclear membrane and sticky incompletely folded chromosomes typical for cadmium treatment [13,27].…”

Gamma irradiation induced apoptotic changes in the chromatin structure of human erythroleukemia K562 cells

“…Chromatin changes induced by cadmium treatment were markedly different from those seen after c-irradiation, but cadmium-induced chromatin changes were the same in different cells. Apoptotic chromatin changes in chromatin structure after cadmium treatment were seen as large extensive disruptions, holes in the nuclear membrane and stickiness of incompletely folded chromosomes [26,27]. After c-irradiation the cellular and nuclear sizes were inceased, the DNA content was lower in each elutriated subpopulation of cells, the progression of cell cycle was arrested in early S phase, the chromatin condensation was blocked between the fibrillary chromatin and precondensed elongated chromosome forms and the number and size of apoptotic bodies were inversely correlated with the progression of the cell cycle [11].…”

Time-Lapse Analysis of Cell Death in Mammalian and Fungal Cells

“…To induce apoptosis, similar concentrations for Pb treatment were applied as earlier when the apoptotic agent was Cd (Banfalvi et al, 2007b). HaCaT cells at about 80% confluence were grown for 15 h, and then 1 mM Pb(NO 3 ) 2 was added to the cell culture and cells were grown further for 9 h. Photographs were taken after 1 day every minute.…”

“…By performing cell cycle synchronization using high resolution of centrifugal elutriation (Banfalvi, 2008a), we could distinguish typical damaged chromatin forms from normal structures in those cells that have undergone apoptosis (Banfalvi et al, 2005(Banfalvi et al, , 2006(Banfalvi et al, , 2007a(Banfalvi et al, , 2007bUjvarosi et al, 2007;Banfalvi, 2008bBanfalvi, , 2009). The morphological investigations of apoptosis, which are based primarily on microscopy (Kerr et al, 1995;Gorman et al, 1996;Kravtsov et al, 1999), grasped only moments of the process.…”