The relationship between metastatic potential and in vitro mechanical properties of osteosarcoma cells.

Osteosarcoma is the most frequent primary tumor of bone and is characterized by its high tendency to metastasize in lungs. Although in case of being early diagnosed treatment results in a 5-year survival rate of nearly 60%, prognosis of patients with secondary lesions at diagnosis is poor and their 5-year survival rate remains below 30%. In the present work we have used a number of analytical methods to investigate the impact of increased metastatic potential on the biophysical properties and force generation of osteosarcoma cells. With that aim we used two paired osteosarcoma cell lines, with each one comprising a parental line with low metastatic potential and its experimentally selected, highly metastatic form. Mechanical characterization was performed by means of atomic force microscopy, tensile biaxial deformation and real-time deformability, and cell traction was measured using two-dimensional and micropost-based traction force microscopy. Our results reveal that the low metastatic osteosarcoma cells display larger spreading sizes and generate higher forces than the experimentally selected highly malignant variants. In turn, the outcome of the cell-stiffness measurements strongly depends on the used method and state of the probed cell, indicating that only a set of phenotyping methods provides the full picture of cell mechanics.