AQP3 Increases Intercellular Cohesion in NSCLC A549 Cell Spheroids through Exploratory Cell Protrusions

Area of Science:

• Cell Biology
• Cancer Research
• Biophysics

Background:

• Tumor cell aggregation is crucial for survival after losing matrix attachment and during metastasis.
• The mechanotransduction mechanisms driving solitary tumor cell clustering, particularly in non-small cell lung cancer (NSCLC), remain unclear.
• Cell surface protrusions may mediate physical contact between detached, floating tumor cells.

Purpose of the Study:

• To investigate the role of cell surface protrusions in the aggregation of free-floating tumor cells.
• To elucidate the mechanotransduction pathways involved in tumor cell clustering in NSCLC.
• To determine the function of aquaporin 3 (AQP3) in cell aggregation and migration.

Main Methods:

• Utilized poly-2-hydroxyethyl methacrylate-based 3D culture to mimic in vivo tumor cell cluster formation.
• Performed suprastructural analysis and time-lapse holotomography on human NSCLC A549 cell spheroids.
• Conducted global gene expression analysis and aquaporin 3 (AQP3) gene knockdown experiments.

Main Results:

• Finger-like protrusions, stabilized by the actin cytoskeleton, were observed in A549 cell spheroids.
• Free-floating cells exhibited exploratory coalescence of these protrusions.
• Knockdown of AQP3 disrupted multicellular aggregate formation via actomyosin cytoskeleton rearrangement and reduced cell transmigration.

Conclusions:

• Cell detachment upregulates AQP3, which drives cell surface protrusions through actomyosin remodeling.
• AQP3-mediated aggregation of free-floating cells is critical for collective metastasis.
• These findings highlight AQP3's role in NSCLC aggressiveness and metastatic potential.