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The Scientific World Journal
Volume 2014, Article ID 618698, 10 pages
http://dx.doi.org/10.1155/2014/618698
Research Article

Identification of p53 and Its Isoforms in Human Breast Carcinoma Cells

1Laboratory of Molecular Biology and Endocrinology, “Vinča” Institute of Nuclear Sciences, University of Belgrade, Mihaila Petrovića Alasa 12-14, P.O. Box 522, 11 001 Belgrade, Serbia
2Biomedical Department, Institute for Pharmaceutical Research and Development, Galenika a.d., Pasterova 2, 11 000 Belgrade, Serbia
3Department of Biology and Human Genetics, Institute of Physiology, Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11 000 Belgrade, Serbia
4Department of Chemistry, Institute for Chemistry, Technology and Metallurgy, University of Belgrade, Studentski trg 12-16, 11000 Belgrade, Serbia

Received 4 September 2013; Accepted 12 November 2013; Published 5 January 2014

Academic Editors: N. L. Banik and T. Mikawa

Copyright © 2014 Zorka Milićević et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

In breast carcinoma, disruption of the p53 pathway is one of the most common genetic alterations. The observation that the p53 can express multiple protein isoforms adds a novel level of complexity to the outcome of p53 mutations. p53 expression was analysed by Western immunoblotting and immunohistochemistry using monoclonal antibodies DO-7, Pab240, and polyclonal antiserum CM-1. The more frequently p53-positive nuclear staining has been found in the invasive breast tumors. One of the most intriguing findings is that mutant p53 appears as discrete dot-shaped regions within the nucleus of breast cancer cells. In many malignant cells, the nucleolar sequestration of p53 is evident. These observations support the view that the nucleolus is involved directly in the mediation of p53 function or indirectly by the control of the localization of p53 interplayers. p53 expressed in the nuclear fraction of breast cancer cells revealed a wide spectrum of isoforms. p53 isoforms ΔNp53 (47 kDa) and Δ133p53β (35 kDa), known as dominant-negative repressors of p53 function, were detected as the most predominant variants in nuclei of invasive breast carcinoma cells. The isoforms expressed also varied between individual tumors, indicating potential roles of these p53 variants in human breast cancer.