Ultrastructural Complexity of Nuclear Components During Early Apoptotic Phases in Breast Cancer Cells

Abstract

Fractal morphometry was used to investigate the ultrastructural features of the plasma membrane, perinuclear membrane and nuclear chromatin in SK‐BR‐3 human breast cancer cells undergoing apoptosis. Cells were incubated with 1 μM calcimycin (A23187) for 24 h. Cells in the early stage of apoptosis had fractal dimension (FD) values indicating that their plasma membranes were less rough (lower FD) than those of control cells, while their perinuclear membranes were unaffected. Changes of the chromatin texture within the entire nucleus and in selected nuclear domains were more pronounced in treated cells. This confirms that the morphological reorganization imputable to a loss of structural complexity (reduced FD) occurs in the early stage of apoptosis, is accompanied by the inhibition of distinct enzymatic events and precedes the onset of conventional cellular markers, which can only be detected during the active phases of the apoptotic process.

Nuclear patterns of human breast cancer cells during apoptosis: characterisation by fractal dimension and co-occurrence matrix statistics

“…However, evidence for the spatial-textural reorganisation of nuclear chromatin in the early apoptotic phases of SK-BR-3 cells is provided by the changes in six out of thirteen second-order statistics parameters estimated by GLCM analysis. These findings support the low FD data presented in a previous paper, in which fractal analysis alone was used to characterise early phases of apoptosis by quantifying ultrastructural changes of cellular membranes and nuclear components (Castelli and Losa 2001). The behaviour and the ultrastructural rearrangement of nuclear domains and ribonucleoprotein-containing structures have been documented during overt apoptosis of lymphoid cells by conventional morphological and morphometric approaches (Falcieri et al 1994a(Falcieri et al , 1994bBiggiogera et al 1997;Stuppia et al 1996).…”

“…They underline the possible involvement of sialosphingolipid molecules, such as GM 3 and GD 3 , as signalling mediators and inducers of apoptosis (De Maria et al 1997;Marquina et al 1996;Nojiri et al 1999). At first glance, the loss of membrane gangliosides and their altered expression, which is caused by the apoptotic process and might be attributable to reduced expression by a shedding mechanism and/or to altered metabolic pathways, are in agreement with the reduction of the ultrastructural complexity of the plasma membrane at the initial and late phases of apoptosis (Castelli and Losa 2001). Our finding of a loss of morphological traits in the nuclei of calcimycininduced apoptotic cells supports data reported by authors who have shown a significant reduction in the FD of intranuclear chromatin in lymphoid Jurkat cells, in which apoptosis had been induced with APO/Fas (Santoro et al 2002).…”

“…Fractal morphometry has been employed to analyse electronmicroscopic (EM) images and to characterise nuclear euchromatin and heterochromatin domains (Chan 1995;Marinelli et al 1998) of lymphoid cells , normal and malignant liver cell nuclei (Nielsen et al 1999), lymphocytic nuclear membranes in Mycosis fungoides and chronic dermatitis (Bianciardi et al 2002) and pericellular membranes of healthy immune competent lymphocytes and human leukemic cells (Losa et al 1992). Recently, the fractal method was employed to document the feasibility of using ultrastructural changes in cell surface and nuclear inter(eu)chromatin to assess the early phases of apoptosis in human breast cancer cells prior to changes in conventional cell markers (Castelli and Losa 2001). Methods based on grey-level density discrimination have been applied to histological sections to measure the FD of the chromatin texture of nuclei in normal and malignant cells (Landini and Rippin 1996;Irinopoulou et al 1993;MacAulay and Palcic 1990;Doudkine et al 1995;Einstein et al 1998;Wehn et al 1999).…”

Extracting Diagnostic Information from Optical Coherence Tomography Images of Diabetic Retinal Tissues Using Depth-dependent Attenuation rate and Fractal Analysis

“…A decrease of this parameter in case of pathologic retinal deformation, or degradation due to apoptosis (cell death) is expected. 1 As cells undergo this apoptosis process, bodies within the cell, like the nucleus or mitochondria, go through structural changes. Apoptotic changes can be detected by analyzing the light scattered by these bodies.…”

“…Two classification methods were used. The first method is based on finding the attenuation coefficients for the OCT signal that propagates through various regions of the retinal tissue [1].…”