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Biochemistry Research International
Volume 2013 (2013), Article ID 730874, 9 pages
http://dx.doi.org/10.1155/2013/730874
Review Article

Cell Shape and Cardiosphere Differentiation: A Revelation by Proteomic Profiling

1Department of Pediatric Cardiology, Tokyo Women’s Medical University, 8-2, Kawada-cho, Shinjuku, Tokyo 162-8666, Japan
2Department of Legal Medicine, School of Medicine, Tokyo Women’s Medical University, 8-1 Kawada-cho, Shinjuku, Tokyo 162-8666, Japan
3University of Toronto and University Health Network, Toronto, ON, M5G1L7, Canada
4Nihon Pharmaceutical University, 10281 Inacho-komuro, Kita-adachi-gun, Saitama-ken, Saitama 362-0806, Japan

Received 30 April 2013; Accepted 8 July 2013

Academic Editor: Jan A. Miernyk

Copyright © 2013 Nanako Kawaguchi 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

Stem cells (embryonic stem cells, somatic stem cells such as neural stem cells, and cardiac stem cells) and cancer cells are known to aggregate and form spheroid structures. This behavior is common in undifferentiated cells and may be necessary for adapting to certain conditions such as low-oxygen levels or to maintain undifferentiated status in microenvironments including stem cell niches. In order to decipher the meaning of this spheroid structure, we established a cardiosphere clone (CSC-21E) derived from the rat heart which can switch its morphology between spheroid and nonspheroid. Two forms, floating cardiospheres and dish-attached flat cells, could be switched reversibly by changing the cell culture condition. We performed differential proteome analysis studies and obtained protein profiles distinct between spherical forms and flat cells. From protein profiling analysis, we found upregulation of glycolytic enzymes in spheroids with some stress proteins switched in expression levels between these two forms. Evidence has been accumulating that certain chaperone/stress proteins are upregulated in concert with cellular changes including proliferation and differentiation. We would like to discuss the possible mechanism of how these aggregates affect cell differentiation and/or other cellular functions.