Cell cycle model selection for leukemia and its impact in chemotherapy outcomes
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2015 Elsevier B.V. The cell cycle is the biological process used by cells to replicate their genetic material and give birth to new cells that are in turn eligible to proliferate. It is highly regulated by the timed expression of proteins which trigger cell cycle events such as the start of DNA replication or the commencement of mitosis (when the cell physically divides into two daughter cells). Mathematical models of the cell cycle have been widely developed both at the intracellular (protein kinetics) and macroscopic (cell duplication) levels. Due to the cell cycle specificity of most chemother-apeutic drugs, these models are increasingly being used for the study and simulation of cellular kinetics in the area of cancer treatment. In this work, we present a population balance model (PBM) of the cell cycle in leukemia that uses intracellular protein expression as state variable to represent phase progress. Global sensitivity analysis highlighted cell cycle phase durations as the most significant parameters; experiments were performed to extract them and the model was validated. Our model was then tested against other differential cell cycle models (ODEs, delay differential equations (DDEs)) in their ability to fit experimental data and oscillatory behavior. We subsequently coupled each of them with a pharmacokinetic/pharmacodynamic model of chemotherapy delivery that was previously developed by our group. Our results suggest that the particular cell cycle model chosen highly affects the outcome of the simulated treatment, given the same steady-state kinetic parameters and drug dosage/scheduling, with our PBM appearing to be the most sensitive under the same dose.