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Open Access Primary research

Low-dose etoposide-treatment induces endoreplication and cell death accompanied by cytoskeletal alterations in A549 cells: Does the response involve senescence? The possible role of vimentin

Anna Litwiniec1*, Lidia Gackowska2, Anna Helmin-Basa2, Agnieszka Żuryń3 and Alina Grzanka3

Author Affiliations

1 Laboratory of Biotechnology, Department of Genetics and Breeding of Root Crops, Plant Breeding and Acclimatization Institute - National Research Institute Radzików, 05-870 Błonie, Research Division in Bydgoszcz, Powstańców Wielkopolskich 10, 85-090, Bydgoszcz, Poland

2 Laboratory of Clinical and Experimental Immunology, Department of Immunology, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Curie Skłodowskiej 9, 85-094, Bydgoszcz, Poland

3 Department of Histology and Embryology, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Karłowicza 24, 85-092, Bydgoszcz, Poland

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Cancer Cell International 2013, 13:9  doi:10.1186/1475-2867-13-9

Published: 5 February 2013

Abstract

Background

Senescence in the population of cells is often described as a program of restricted proliferative capacity, which is manifested by broad morphological and biochemical changes including a metabolic shift towards an autophagic-like response and a genotoxic-stress related induction of polyploidy. Concomitantly, the cell cycle progression of a senescent cell is believed to be irreversibly arrested. Recent reports suggest that this phenomenon may have an influence on the therapeutic outcome of anticancer treatment. The aim of this study was to verify the possible involvement of this program in the response to the treatment of the A549 cell population with low doses of etoposide, as well as to describe accompanying cytoskeletal alterations.

Methods

After treatment with etoposide, selected biochemical and morphological parameters were examined, including: the activity of senescence-associated ß-galactosidase, SAHF formation, cell cycle progression, the induction of p21Cip1/Waf1/Sdi1 and cyclin D1, DNA strand breaks, the disruption of cell membrane asymmetry/integrity and ultrastructural alterations. Vimentin and G-actin cytoskeleton was evaluated both cytometrically and microscopically.

Results and conclusions

Etoposide induced a senescence-like phenotype in the population of A549 cells. Morphological alterations were nevertheless not directly coupled with other senescence markers including a stable cell cycle arrest, SAHF formation or p21Cip1/Waf1/Sdi1 induction. Instead, a polyploid, TUNEL-positive fraction of cells visibly grew in number. Also upregulation of cyclin D1 was observed. Here we present preliminary evidence, based on microscopic analyses, that suggest a possible role of vimentin in nuclear alterations accompanying polyploidization-depolyploidization events following genotoxic insults.

Keywords:
Senescence-like phenotype; Etoposide; Polyploidy; Depolyploidization; Vimentin; G-actin