Investigating Heterogeneity in the Long-term Maintenance of Cellular Phenotype Following Ionizing Radiation
Year: 2023
Type: dissertation
Abstract: Ionizing radiation (IR) is commonly used to kill cancer cells by causing DNA damage. Cells initiate DNA repair pathways and cell cycle arrests to suppress cell death, and the differential activation of these pathways can lead to several distinct fates in neighbouring irradiated cells. Some cells die rapidly by apoptosis, some proliferate indefinitely, while others activate another mode of cell death or permanently exit the cell cycle into senescence. We established scRNA-seq data analysis pipelines for tracing transcriptionally heterogeneous fates in vitro, and my preliminary data demonstrate separable gene expression when a homogeneous cell population (MCF10A cells) is irradiated. My work is focused on establishing a long-term live-cell imaging assay for tracing the diverse fates of irradiated cells at the single-cell level. Using this system, the timepoint, frequency, and state of cell divisions can be observed in normal and pharmacologically modified conditions, and we traced fate outcomes in cells irradiated during different cell cycle phases as DNA damage burden increases, as classical DNA damage response kinases are inhibited, and when cell fate is artificially directed towards different modes of death. Through fate mapping of single-cells, I envision this system as an aid to establishing novel deterministic features of IR-induced cell fate outcomes, identifying candidate pathways associated with fate emergence for further investigation, and guiding novel avenues for rationally shaping heterogeneity in fate following IR. This will provide a deeper understanding of why some cells are responsive to treatment, activating favorable modes of cell death, while others are left behind to repopulate a tumor and drive local cancer recurrence after treatment.
Source: TSpace (University of Toronto)
Author: Mohamed Tageldein, Maha
Institution: University of Toronto
Language: English
Subfield: Radiology, Nuclear Medicine and Imaging
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W7133003830