Cancer cells form thin fibers that connect them to each other, called tunneling nanotubes (TNTs), which enable intercellular communication. TNTs are understood to serve as pathways for the transmission of various cellular materials and signals and are thought to play roles in cellular physiological activity and the survival of cancer cells. We investigated the mechanical properties of TNTs by varying the elastic modulus of cell adhesion substrates (E = ~GPa, ~MPa, ~100kPa), based on the hypothesis that TNTs may contribute to the transmission of mechanical stress between cells. First, we observed cell adhesion to substrate with different elastic modulus using human cervical cancer (HeLa) cells under fluorescence microscopy. Then, the internal tension, axial spring constant, and elastic modulus of TNTs were estimated from force-displacement curves obtained by indentation measurements using an atomic force microscope. As a result, it was shown that the cell adhesion area and TNT internal tension increased on the hard substrate with elastic modulus in the GPa range, and no significant difference were observed in TNT axial spring constants and TNT elastic modulus. However, no differences were observed in cell adhesion area or TNT mechanical properties between the substrate with the ~100 kPa and MPa orders. HeLa cells might not be able to detect these slight differences in the elasticity of the substrate. Overall, our results indicate that TNTs may influence neighboring cells by transmitting mechanical cues in a manner dependent on the extracellular mechanical environment.
Ota et al. (Wed,) studied this question.