Migration of anchorage-dependent mammalian cells
Doctor of Philosophy
Cell migration affects many physiologic and pathologic processes in mammalian organisms. Thus, our ability to modulate these processes depends on understanding how cell migration is controlled by soluble factors, cell-substrate interactions and metabolic pathways. To accurately quantify the effects of external stimuli, cell migration was studied using a computer-automated technique that combined video microscopy, digital time-lapse and image analysis. This approach enabled us to monitor large cell populations and characterize the migration behavior of individual cells. The effect of receptor/ligand interactions on the migration of endothelial cells was studied first. Bioactive glass surfaces were prepared by covalently binding on them short adhesive peptides and the spatial distribution of the bound peptides was characterized with fluorescence studies. Locomotion analysis showed that endothelial cells migrated on the bioactive surfaces with significantly increased persistence and random motility coefficients. Since migration is a major factor in determining proliferation rates of anchorage-dependent cells, this type of surface modification can be used to accelerate the endothelization of synthetic vascular grafts and increase their implantation success rates. The role of metabolism on cell motility was investigated by testing the hypothesis that glycolysis is required for cancer cell migration. Our measurements demonstrated that rat prostate cancer cells grown in conditioned media did not require glucose to maintain migration. Conditioned media helped these cells adapt to inhibition of glycolysis or mitochondrial respiration by increasing activity of the uninhibited pathway. To test the ability of soluble factors to protect the endothelium and improve its wound healing response, we studied the morphology and migration of endothelial cells exposed to ionizing irradiation. Soluble growth factors had no effect on the migration speed of endothelial cells and did not reverse the hyperplasia observed after exposing these cells to radiation. However, heparin significantly reduced irradiated cell size especially when used together with basic fibroblast growth factor. Finally, a computer model was developed to describe the dynamics of large populations of migrating, interacting and proliferating cells. Simulation results agreed well with experimental data. This model has predictive capabilities that make it particularly useful for tissue engineering applications.
Cell biology; Chemical engineering