Mapping Cell-in-Cell Structures in Oral Squamous Cell Carcinoma.

Area of Science:

• Oncology
• Cell Biology
• Biotechnology

Background:

• Cell-in-cell (CIC) structures are linked to aggressive oral squamous cell carcinoma (OSCC) and poor patient outcomes.
• Understanding the molecular mechanisms of CIC formation in OSCC requires advanced in vitro models.

Purpose of the Study:

• To investigate cell-in-cell (CIC) structures in oral squamous cell carcinoma (OSCC) using a 3D spheroid model.
• To analyze the formation, morphology, and location of CIC structures within the tumor microenvironment.

Main Methods:

• Oral squamous cell carcinoma (OSCC) and cancer-associated fibroblast (CAF) cell lines were cultured into spheroids using a bioprinting system.
• Spheroid morphology, including hypoxic and proliferative zones, was analyzed over time using microscopy and image analysis software.
• Cell-in-cell structure occurrence, complexity, and morphology were assessed within different spheroid regions.

Main Results:

• Well-formed spheroids mimicking the tumor microenvironment (hypoxic core, proliferative periphery) developed within 6 hours.
• Cell-in-cell (CIC) structures were observed in both homotypic and heterotypic spheroids.
• CIC structures were predominantly found in the proliferative zones of mixed OSCC/CAF spheroids, with instances of 'complex cannibalism' noted.

Conclusions:

• The 3D spheroid model effectively replicates key features of the OSCC tumor microenvironment, including CIC formation.
• This model provides a valuable platform for further research into the morphology, development, and prognostic significance of CIC structures in OSCC.