Evaluating the effects reduced EMI1 expression has on chromosome instability and cellular transformation in colorectal cancer
| dc.contributor.author | Campos GudiƱo, Rubi | |
| dc.contributor.examiningcommittee | Wigle, Jeffrey (Biochemistry and Medical Genetics) | |
| dc.contributor.examiningcommittee | Hombach-Klonisch, Sabine (Human Anatomy and Cell Science) | |
| dc.contributor.supervisor | McManus, Kirk | |
| dc.date.accessioned | 2023-07-31T18:41:22Z | |
| dc.date.available | 2023-07-31T18:41:22Z | |
| dc.date.issued | 2023-07-26 | |
| dc.date.submitted | 2023-07-26T19:10:34Z | en_US |
| dc.degree.discipline | Biochemistry and Medical Genetics | en_US |
| dc.degree.level | Master of Science (M.Sc.) | |
| dc.description.abstract | Colorectal cancer (CRC) is the fourth most diagnosed and second most lethal cancer in Canada. As such, understanding the aberrant genetics driving disease development is critical to ultimately develop early detection methods or novel therapeutic strategies aimed at improving the lives and outcomes of CRC patients. Chromosome instability (CIN), or ongoing changes in chromosome complements, is a predominant form of genome instability and driver of genetic and cell-to-cell heterogeneity associated with ~85% of CRCs, suggesting it may be a key mechanism driving CRC development. CIN enables the acquisition of copy number alterations conferring selective growth, proliferation and survival advantages. Despite these associations, the aberrant genes underlying CIN remain mostly unknown. Preliminary screens of potential CIN genes identified EMI1 as a strong candidate CIN gene as its reduced expression resulted in increased CIN-associated phenotypes. EMI1 encodes an F-box protein, a subunit of the SCF complex that ubiquitylates proteins, targeting them for their proteolytic degradation via the 26S proteasome. However, the impact reduced EMI1 expression has on CIN, cellular transformation and oncogenesis remains unknown. Therefore, the current study seeks to provide novel insight into the effects diminished EMI1 expression has on CIN and cellular transformation in a CRC context. I hypothesize that reduced EMI1 expression induces CIN that promotes cellular transformation. I addressed this hypothesis by evaluating the short- and long-term impact diminished EMI1 expression has on malignant and non-malignant colonic epithelial cells. Briefly, siRNA and CRISPR/Cas9 approaches coupled with single-cell quantitative imaging microscopy (QuantIM) were employed to assess changes in CIN-associated phenotypes. Analyses revealed that short-term EMI1 silencing induced significant increases in nuclear areas, micronucleus formation and aberrant chromosome numbers relative to controls. In the long-term experiments, EMI1 clones exhibited ongoing and statistically significant changes in CIN-associated phenotypes over ~2.5 months. Chromosome enumeration revealed EMI1 clones exhibited dynamic changes in chromosome numbers over time. The ongoing changes in chromosome complements (i.e., CIN) corresponded with various cellular transformation phenotypes, including increased proliferation and anchorage-independent growth. Collectively, this work identifies EMI1 as a novel CIN gene in clinically relevant models, suggesting EMI1 may contribute to early pathogenic events driving CRC development. | |
| dc.description.note | October 2023 | |
| dc.identifier.uri | http://hdl.handle.net/1993/37436 | |
| dc.language.iso | eng | |
| dc.rights | open access | en_US |
| dc.subject | Colorectal cancer | |
| dc.subject | Chromosome instability | |
| dc.subject | SCF Complex | |
| dc.subject | EMI1 | |
| dc.subject | Quantitative imaging microscopy | |
| dc.subject | CRISPR/Cas9 | |
| dc.title | Evaluating the effects reduced EMI1 expression has on chromosome instability and cellular transformation in colorectal cancer | |
| dc.type | master thesis | en_US |
| local.subject.manitoba | no |