Altered expression pattern of integrin alphavbeta3 correlates with actin cytoskeleton in primary cultures of human breast cancer

Sophia Havaki¹ , Mirsini Kouloukoussa¹ , Kawther Amawi¹ , Yiannis Drosos² , Leonidas D Arvanitis³ , Nikos Goutas⁴ , Dimitrios Vlachodimitropoulos⁴ , Stamatis D Vassilaros⁵ , Eleni Z Katsantoni⁶ , Irene Voloudakis-Baltatzis⁷ , Vassiliki Aleporou-Marinou² , Christos Kittas¹ and Evangelos Marinos¹

¹Laboratory of Histology and Embryology, Medical School, University of Athens, 75 Mikras Asias Str., 11527 Goudi, Greece

²Department of Genetics and Biotechnology, School of Biology, University of Athens, Panepistimioupoli, 15701 Ilissia, Greece

³Department of Anatomy and Pathology, Medical School, University of Thessaly, 22 Papakiriazi Str., 41222, Larissa, Greece

⁴Laboratory of Forensic Medicine and Toxicology, Medical School, University of Athens, 75 Mikras Asias Str., 11527 Goudi, Greece

⁵Prolipsis" Medical Centre, 3 Sevastias Str., Athens, Greece

⁶Hematology Division, Biomedical Research Foundation, Academy of Athens, 4 Soranou Ephesiou, 11527 Athens, Greece

⁷Department of Electron Microscopy and Cell Biology, Research Centre of Oncology "G. Papanikolaou", Saint Savvas Anticancer Hospital, Alexandras Av. 171, Athens, Greece

author email corresponding author email

Cancer Cell International 2007, 7:16doi:10.1186/1475-2867-7-16


Published:	2 October 2007

Abstract

Background

Integrins are transmembrane adhesion receptors that provide the physical link between the actin cytoskeleton and the extracellular matrix. It has been well established that integrins play a major role in various cancer stages, such as tumor growth, progression, invasion and metastasis. In breast cancer, integrin alphavbeta3 has been associated with high malignant potential in cancer cells, signaling the onset of widespread metastasis. Many preclinical breast cancer studies are based on established cell lines, which may not represent the cell behavior and phenotype of the primary tumor of origin, due to undergone genotypic and phenotypic changes. In the present study, short-term primary breast cancer cell cultures were developed. Integrin alphavbeta3 localization was studied in correlation with F-actin cytoskeleton by means of immunofluorescence and immunogold ultrastructural localization. Integrin fluorescence intensities were semi-quantitatively assessed by means of computerized image analysis, while integrin and actin expression was evaluated by Western immunoblotting.

Results

In the primary breast cancer epithelial cells integrin alphavbeta3 immunofluorescence was observed in the marginal cytoplasmic area, whereas in the primary normal breast epithelial cells it was observed in the main cell body, i.e. in the ventrally located perinuclear area. In the former, F-actin cytoskeleton appeared well-formed, consisting of numerous and thicker stress fibers, compared to normal epithelial cells. Furthermore, electron microscopy showed increased integrin alphavbeta3 immunogold localization in epithelial breast cancer cells over the area of stress fibers at the basal cell surface. These findings were verified with Western immunoblotting by the higher expression of integrin beta3 subunit and actin in primary breast cancer cells, revealing their reciprocal relation, in response to the higher motility requirements, determined by the malignant potential of the breast cancer cells.

Conclusion

A model system of primary breast cancer cell cultures was developed, in an effort to maintain the closest resembling environment to the tumor of origin. Using the above system model as an experimental tool the study of breast tumor cell behavior is possible concerning the adhesion capacity and the migrating potential of these cells, as defined by the integrin alphavbeta3 distribution in correlation with F-actin cytoskeleton.