RT Journal Article SR Electronic T1 A stochastic mathematical model of 4D tumour spheroids with real-time fluorescent cell cycle labelling JF bioRxiv FD Cold Spring Harbor Laboratory SP 2021.11.28.470300 DO 10.1101/2021.11.28.470300 A1 Jonah J. Klowss A1 Alexander P. Browning A1 Ryan J. Murphy A1 Elliot J. Carr A1 Michael J. Plank A1 Gency Gunasingh A1 Nikolas K. Haass A1 Matthew J. Simpson YR 2021 UL http://biorxiv.org/content/early/2021/11/29/2021.11.28.470300.abstract AB In vitro tumour spheroid experiments have been used to study avascular tumour growth and drug design for the last 50 years. Unlike simpler two-dimensional cell cultures, tumour spheroids exhibit heterogeneity within the growing population of cells that is thought to be related to spatial and temporal differences in nutrient availability. The recent development of real-time fluorescent cell cycle imaging allows us to identify the position and cell cycle status of individual cells within the growing population, giving rise to the notion of a four-dimensional (4D) tumour spheroid. In this work we develop the first stochastic individual-based model (IBM) of a 4D tumour spheroid and show that IBM simulation data qualitatively and quantitatively compare very well with experimental data from a suite of 4D tumour spheroid experiments performed with a primary human melanoma cell line. The IBM provides quantitative information about nutrient availability within the spheroid, which is important because it is very difficult to measure these data in standard tumour spheroid experiments. Software required to implement the IBM is available on GitHub, https://github.com/ProfMJSimpson/4DFUCCI.Competing Interest StatementThe authors have declared no competing interest.