A theoretical investigation of the effect of proliferation and adhesion on monoclonal conversion in the colonic crypt

• Published in: Journal of theoretical biology 2012-11, Vol.312, p.143-156
• Main Authors: Mirams, Gary R., Fletcher, Alexander G., Maini, Philip K., Byrne, Helen M.
• Format: Article
• Language: English
• Subjects: Algorithms; Cell Adhesion; Cell Proliferation; Cell Transformation, Neoplastic - genetics; Cell Transformation, Neoplastic - pathology; Clonal expansion; Clone Cells - cytology; Clone Cells - metabolism; Colon - cytology; Colon - metabolism; Colorectal crypt; Computer Simulation; Epithelial Cells - cytology; Epithelial Cells - metabolism; Humans; Intestinal Mucosa - cytology; Intestinal Mucosa - metabolism; Mathematical model; Models, Biological; Mutation; Stem cell
• ISSN: 0022-5193; 1095-8541
• DOI: 10.1016/j.jtbi.2012.08.002

The surface epithelium lining the intestinal tract renews itself rapidly by a coordinated programme of cell proliferation, migration and differentiation events that is initiated in the crypts of Lieberkühn. It is generally believed that colorectal cancer arises due to mutations that disrupt the normal cellular dynamics of the crypts. Using a spatially structured cell-based model of a colonic crypt, we investigate the likelihood that the progeny of a mutated cell will dominate, or be sloughed out of, a crypt. Our approach is to perform multiple simulations, varying the spatial location of the initial mutation, and the proliferative and adhesive properties of the mutant cells, to obtain statistical distributions for the probability of their domination. Our simulations lead us to make a number of predictions. The process of monoclonal conversion always occurs, and does not require that the cell which initially gave rise to the population remains in the crypt. Mutations occurring more than one to two cells from the base of the crypt are unlikely to become the dominant clone. The probability of a mutant clone persisting in the crypt is sensitive to dysregulation of adhesion. By comparing simulation results with those from a simple one-dimensional stochastic model of population dynamics at the base of the crypt, we infer that this sensitivity is due to direct competition between wild-type and mutant cells at the base of the crypt. We also predict that increases in the extent of the spatial domain in which the mutant cells proliferate can give rise to counter-intuitive, non-linear changes to the probability of their fixation, due to effects that cannot be captured in simpler models. ► We use a spatial cell-based model to study monoclonal conversion in the crypt. ► Mutations are introduced with varied height, proliferation and adhesion. ► Mutations occurring more than one cell from the crypt base rarely dominate. ► Changes to adhesion can significantly affect probability of domination. ► Changes to proliferation cause non-linear changes to the probability of domination.