2Institute of Carcinogenesis, Blokhin Cancer Research Center, Russian Academy of Medical Sciences, Kashirskoe Shosse 24, 115478 Moscow, Russia; fax: (499) 324-1205
3Institute of Clinical Oncology, Blokhin Cancer Research Center, Russian Academy of Medical Sciences, Kashirskoe Shosse 23, 115478 Moscow, Russia
4Dept of Pathology and Immunology, Faculty of Medicine, University of Geneva, CMU, Geneva, Switzerland
* To whom correspondence should be addressed.
Received May 16, 2012; Revision received June 25, 2012
Malignant cell transformation requires changes in the ability of cells to migrate. The disruption of actin cytoskeleton and intercellular adhesions is an important component of the acquisition of invasive properties in epithelial malignancies. The invasive ability of carcinoma cells is associated with reduced expression of adhesion junction molecules and increased expression of mesenchymal markers, frequently referred to as epithelial-to-mesenchymal transition (EMT). Standard features of the EMT program in cancer cells include fibroblastic phenotype, downregulation of the epithelial marker E-cadherin, induction of Snail-family transcription factors, as well as expression of mesenchymal proteins. We compared the epithelial and mesenchymal marker profiles of nonmalignant HaCaT keratinocytes to the corresponding profiles of cervical carcinoma cell lines C-33A, SiHa, and CaSki. The characteristics of the EMT appeared to be more developed in SiHa and CaSki cervical cancer cells. Further activation of the EMT program in cancer cells was induced by epidermal growth factor. Decreased epithelial marker E-cadherin in CaSki cells was accompanied by increased mesenchymal markers N-cadherin and vimentin. Downregulated expression of E-cadherin in SiHa and CaSki cells was associated with increased expression of Snail transcription factor. Our goal was to study actin reorganization in the EMT process in cell cultures and in tissue. We found that β-cytoplasmic actin structures are disorganized in the cervical cancer cells. The expression of β-cytoplasmic actin was downregulated.
KEY WORDS: epithelial-to-mesenchymal transition, E-cadherin, cervical carcinoma, cytoplasmic actin isoforms