Atomic force microscopy measurement of cytostructural elements involved in the nanodynamics of tumour cell invasion

Cytostructural features associated with the invasive characteristics of brain tumour cells have been inspected and measured with atomic force microscopy. In one case the invadopodia extended from a T98 human glioblastoma cell departed from a linear path by 1 mrad for each 240 nm of axial extension from the point where its curvature began. In another cell, diametrically opposed invadopodia were projected over the collagen substrate and were co-aligned to within < 175 mrad (10°) of a common axis. In the latter case, an estimate of the torque that would be needed to overcome the adhesion forces and rotate the cell via moments applied by the invadopodia led to a value of 7 nN µm. From measurements by others of the interactions between glioma cells and collagen, the implied adhesion force for this cell was ≈ 0.5 nN, which was consistent with still other values reported in the literature. The measured mean radius of the cell was roughly 15 µm. The implications of these results for understanding and slowing the invasion of tumour cells through the extracellular matrix of the brain are discussed.