Cell kinetics in tumour cords studied by a model with variable cell cycle length.

Area of Science:

• Mathematical modeling
• Cancer biology
• Cell kinetics

Background:

• Tumor cords, cylindrical arrangements of tumor cells around blood vessels, are key structures in solid tumors.
• Understanding cell proliferation and kinetics within these cords is vital for predicting tumor growth and response to therapy.
• Previous models often simplified cell movement and cycle dynamics, potentially limiting their accuracy.

Purpose of the Study:

• To develop a mathematical model of cell proliferation in tumor cords at a stationary state.
• To incorporate cell migration and cell cycle variability into the model.
• To compare model predictions with experimental data and assess the impact of migration on kinetic parameter estimation.

Main Methods:

• Developed a continuum mathematical model representing tumor cords.
• Included cell migration from inner to outer zones and a multi-compartment cell cycle model (including a quiescent compartment).
• Accounted for cell-to-cell variability in cycle transit times and microenvironment-dependent kinetic parameter changes.
• Validated the model by comparing its predictions to literature data on labeling index and fraction of labeled mitoses after 3H-thymidine pulse labeling.

Main Results:

• The model successfully describes proliferative behavior and incorporates cell migration and cycle variability.
• Theoretical predictions were compared against experimental tumor data.
• Demonstrated that cell migration within the tumor cord can lead to significant underestimation of cell cycle progression changes along the cord radius.

Conclusions:

• Cell migration is a critical factor influencing the observed cell kinetics in tumor cords.
• Ignoring cell migration can lead to inaccurate assessments of tumor cell proliferation and dynamics.
• The developed model provides a more comprehensive framework for studying tumor cord cell kinetics and can inform therapeutic strategies.