Amorphous silica nanoparticles alter microtubule dynamics and cell migration

Abstract

Amorphous silica nanoparticles (SiO₂-NPs) have been studied for their toxic and genotoxic potential. Although contradictory data have been reported and the possible modes of action are not fully elucidated, aneugenic events have been reported, indicating the microtubule (MT) network as a potential target. To investigate this, we examined the effects of 59 nm (10 µg/ml) and 174 nm (7.5 µg/ml) SiO₂-NPs on MTs in mitotic and interphase A549 human lung carcinoma cells. No gross morphological changes of the mitotic spindle or induction of multipolar spindles were observed upon SiO₂-NPs treatment. The influence of SiO₂-NPs on the interphase MTs network dynamics was investigated by in situ depolymerisation/repolymerisation experiments. Results showed a clear increase in MT dynamics after SiO₂-NP treatment. Consistent with this, reduced levels of MT acetylation were observed. In addition, live cell microscopy demonstrated that SiO₂-NP treatment reduced A549 cell motility. The SiO₂-NP doses and conditions (serum-free) used in this study did not induce significant cell toxicity or MN frequencies. Therefore, the effects on MT dynamics, MT acetylation and migration observed, are direct effects of the SiO₂-NPs and not a consequence of NP overload or toxic or genotoxic effects.

• Cell migration
• in vitro
• microtubule dynamics
• mode of action
• silica nanoparticles

Acknowledgements

Authors acknowledge Dr. Patrizia Lavia for advice and support with optical microscopy and Dr. Leen Thomassen for providing us the fluorescent silica nanoparticles.

Declaration of interest

The authors declare no competing interests. This work was funded by the Belgian Ministry of Scientific Policy in the frame of the ‘‘Science for sustainable development’’ programme [SD/HE/02A]. LG received a postdoctoral fellowship from the Fund for Scientific Research–Flanders (FWO-Vlaanderen). This research is supported by an InterUniversity Attraction Pole grant (IAP-P7-07). Live cell imaging experiments were performed at the Nikon Reference Centre, CNR Institute of Biology, Molecular Medicine and Nanobiotechnology.

Supplementary material available online

Supplementary Table 1 and Figure 1