Direct evidence that tumor cells soften when navigating confined spaces

Area of Science:

• Cellular mechanics
• Cancer biology
• Biophysics

Background:

• Cell mechanical properties influence physiological and pathological processes.
• Invasive cancer cells are often softer than non-tumor cells, suggesting softening aids migration.
• Direct evidence for tumor cell softening during confined migration is lacking.

Purpose of the Study:

• To investigate whether tumor cells soften during migration through confined spaces.
• To elucidate the cellular mechanisms underlying confinement-induced mechanical changes.
• To provide direct evidence for cell softening as a mechanism of cancer invasion.

Main Methods:

• Utilized polydimethylsiloxane microdevices with tapered, fibronectin-coated channels.
• Combined atomic force microscopy (AFM) for mechanical indentation with cell migration tracking.
• Employed superresolution imaging to analyze actomyosin stress fiber architecture.

Main Results:

• U2OS cells exhibited decreased stiffness as they transitioned from unconfined to confined migration.
• Confinement induced nuclear exclusion of Yes-associated protein.
• Actomyosin stress fiber architecture was remodeled by topographical confinement.
• Mechanical changes were intrinsically driven by confinement, not cell shape.

Conclusions:

• Demonstrated direct evidence that cells soften during confined migration.
• Supported cell softening as a mechanoadaptive mechanism facilitating cancer invasion.
• Highlighted the role of topographical confinement in driving cellular mechanical remodeling.