A mechanical model of tumor encapsulation and transcapsular spread

Area of Science:

• Oncology
• Biophysics
• Mathematical Biology

Background:

• Solid tumor growth involves complex physical forces and cellular interactions.
• Tumor encapsulation and spread are critical processes in cancer progression.
• Existing hypotheses for capsule formation include active (foreign body) and passive (expansive growth) mechanisms.

Purpose of the Study:

• To present a mathematical modeling framework for tumor growth, encapsulation, and spread.
• To test and compare active versus passive hypotheses of tumor capsule formation.
• To investigate the role of protease production in transcapsular tumor spread.

Main Methods:

• Development of a mechanical mathematical model simulating tumor physical forces and cellular interactions.
• Model simulations to evaluate capsule formation under active, passive, and combined growth hypotheses.
• Modification of the model to incorporate pressure-dependent protease production by tumor cells.

Main Results:

• Active responses alone, while controlling growth via collagen deposition, are insufficient for capsule formation.
• Passive responses can produce encapsulated tumors with minimal internal connective tissue.
• Combined active and passive responses result in denser capsules and increased intratumoral connective tissue.
• Tumor cell pressure-dependent protease production correlates with transcapsular spread (invasion).

Conclusions:

• Passive expansive growth is crucial for effective tumor encapsulation.
• A combination of active and passive mechanisms leads to more robust capsule formation.
• Tumor cell-produced proteases, influenced by mechanical pressure, are implicated in invasive spread.