Study on Mechanical Properties of Thrombomodulin-transfected Cancer Cells by Atomic Force Microscopy

Thrombomodulin (TM) is a glycoprotein distributed on cell membrane, which can alter the coagulant activity of thrombin in terms of forming complexes with thrombin. Recent studies have demonstrated novel functions of TM on regulating cell-to-cell adhesion and cell morphology of cancer cells. In this study, atomic force microscopy (AFM) was used to investigate the effect of TM on regulating cell morphology and mechanical properties in TM-negative human melanoma A2058 cells (vector cells) and another cell type which transfected with green fluorescent protein-tagged TM (TMG cells). The results showed the cellular morphology of TMG cells having larger flattened fan-shaped lamellipodia protrusion, lower height of the cell-cell junction and clearer stress fiber-like cytoskeleton compared with the vector cells. In addition, the Young's modulus of TMG cells (2646 +/- 309 Pa) was higher than that of TM negative cells (1687 +/- 235 Pa). These preliminary results demonstrate the TM glycoprotein possibly plays an important role to regulate the cellular lamellipodia protrusion, spreading and stiffness.