Mechano-signalling, induced by fullerene C60 nanofilms, arrests the cell cycle in the G2/M phase and decreases proliferation of liver cancer cells.

Degradation of the extracellular matrix (ECM) changes the physicochemical properties and dysregulates ECM-cell interactions, leading to several pathological conditions, such as invasive cancer. Carbon nanofilm, as a biocompatible and easy to functionalize material, could be used to mimic ECM structures, changing cancer cell behavior to perform like normal cells. Experiments were performed in vitro with HS-5 cells (as a control) and HepG2 and C3A cancer cells. An aqueous solution of fullerene C60 was used to form a nanofilm. The morphological properties of cells cultivated on C60 nanofilms were evaluated with light, confocal, electron and atomic force microscopy. The cell viability and proliferation were measured by XTT and BrdU assays. Immunoblotting and flow cytometry were used to evaluate the expression level of proliferating cell nuclear antigen and determine the number of cells in the G2/M phase. All cell lines were spread on C60 nanofilms, showing a high affinity to the nanofilm surface. We found that C60 nanofilm mimicked the niche/ECM of cells, was biocompatible and non-toxic, but the mechanical signal from C60 nanofilm created an environment that affected the cell cycle and reduced cell proliferation. The results indicate that C60 nanofilms might be a suitable, substitute component for the niche of cancer cells. The incorporation of fullerene C60 in the ECM/niche may be an alternative treatment for hepatocellular carcinoma.