Extracellular matrix regulates microfilament and vinculin organization in C6-glioma cells

Since the extracellular matrix (ECM) has a role in regulating cell proliferation it has been hypothesized that unregulated growth of transformed cells results from an inability of cells to interpret the constraints on growth as dictated by the ECM. The most likely candidate to communicate the restraint on growth to the nucleus is the cytoskeleton because it is the only cytoplasmic structure to physically connect the nucleus and plasma membrane. The purpose of this study was to determine whether the cytoskeleton, specifically the microfilaments (MF), of the C6-glioma cell line possesses the ability to respond to changes in the ECM. The C6-glioma cell line was chosen as a model because it exhibits the characteristics of a tumor cell, both in vivo and in vitro. In this study cells were grown on bare glass, Matrigel, laminin and type IV collagen prior to staining with phalloidin tetramethylrhodamine B isothiocyanate or antibodies specific to vinculin to visualize MF and adhesion plaques, respectively. On the basis of MF orientation, network complexity and location of adhesion plaques, this study reports that the cytoskeletal arrangements of C6 cells grown on various substrates are distinctly different. Each distinct organization pattern may reflect a change of cell behavior promoted by the different culture conditions. The significance of this study is that it demonstrates that the process of transformation in C6-glioma cells has not interfered with the cells ability to recognize, interpret and adapt to changes in the ECM.