Single-walled carbon nanotube-induced mitotic disruption

Area of Science:

• Nanotechnology
• Cell Biology
• Occupational Health

Background:

• Carbon nanotubes (CNTs) are widely used in various industries.
• Occupational exposure to CNTs poses risks due to their small size and persistence.
• Previous studies indicated mitotic spindle aberrations from CNT exposure.

Purpose of the Study:

• To investigate the effects of single-walled carbon nanotubes (SWCNTs) on human airway epithelial cells at occupationally relevant concentrations.
• To assess cellular damage, including mitotic spindle disruption and genotoxicity, following SWCNT exposure.

Main Methods:

• Primary and immortalized human airway epithelial cells were exposed to SWCNTs for 24-72 hours.
• Doses were equivalent to 20 weeks of exposure at the Permissible Exposure Limit.
• Cellular damage, including centrosome fragmentation, mitotic spindle disruption, aneuploidy, and cytotoxicity, was analyzed.
• Nanotube localization within cells was examined using 3D reconstructions.

Main Results:

• SWCNT exposure at occupationally relevant doses caused fragmented centrosomes, disrupted mitotic spindles, and aneuploidy.
• Multipolar mitotic spindles constituted 95% of disrupted mitoses, indicating a mitotic checkpoint response.
• SWCNTs were found within centrosome structures and associated with spindle microtubules.
• Significant cytotoxicity was observed after three days, but increased proliferation occurred seven days post-exposure.

Conclusions:

• SWCNTs disrupt the mitotic spindle and centrosome integrity at occupationally relevant doses.
• Observed aneuploidy and increased proliferation suggest a potential role in tumorigenesis and cancer progression.
• Caution is advised during the handling and processing of SWCNTs due to their genotoxic potential.