Regensburg 2013 – scientific programme

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BP: Fachverband Biologische Physik

BP 32: Cell Adhesion and Mechanics

BP 32.9: Talk

Friday, March 15, 2013, 11:45–12:00, H43

Impact of Temperature on Cell Nuclei Integrity — •Enrico Warmt, Tobias Kießling, Roland Stange, Anatol Fritsch, and Josef Käs — Universität Leipzig, Germany

The deformation of cells in Optical Stretcher experiments is considered to be caused exclusively by the deformation of the cellular cytoskeleton. However, the visual appearance of certain cell types during the stretching process implicates events taking place in the cell organelles, especially the cell nucleus. To obtain a more detailed view into the cell we dyed the nucleus in different cell lines and stretched many cells to examine the behavior of the nucleus. At a certain laser power, we observe an abrupt restructuring of the nucleus of MCF-7 cells. This restructuring is irreversible and does not occur during a second stretch of the same cell. Interestingly, the intensity of the restructuring differs between cell lines in a highly reproducible way: While MCF-7 and HMEC show a significant restructuring, less or almost no restructuring is observed on MDA-MB-231, MDA-MB-436 and MCF-10A cells. By controlling the ambient temperature, we show that restructuring is triggered by a laser-induced increase in temperature during measurement and occurs at 45 to 55 °C. It is known that the nuclear matrix as well as the nuclear lamina is thermolabile and some proteins denature in this temperature range, which potentially causes the observed nuclear restructuring and probably leads to cell death. The underlying physical processes and the origin of the variations among cell lines have to be clarified.