The Role of Mitotic Gene Bookmarking in the Epithelial-to-Mesenchymal Transition in Breast Cancer
Conference Year
January 2019
Abstract
The epithelial to mesenchymal transition (EMT), a cellular transformation through which epithelial cells lose their adhesive properties and epithelial phenotype for a migratory and often aggressive/invasive mesenchymal phenotype, plays an important role in the initiation of breast cancer. Previous studies by our group have shown that loss of the RUNX1 transcription factor leads to the initiation of the EMT in mammary breast epithelial cells. However, the precise epigenetic mechanism by which RUNX1 maintains the epithelial phenotype remains incompletely understood. We hypothesize that RUNX1 functions through mitotic gene bookmarking, an epigenetic mechanism in which RUNX1 occupies target genes throughout mitosis to regulate their expression immediately after mitosis and maintain normal cellular proliferation, differentiation, and phenotype. A recent study in our lab showed retention of RUNX1 on a subset of RNA Pol - I and II - transcribed protein coding genes and long non-coding RNA genes important in determination of epithelial phenotype. Inhibition of RUNX1 DNA binding resulted in distinct changes in cellular morphology, gene expression, and global protein synthesis. This study provides the conceptual framework for my project, i.e., to characterize the role(s) of a candidate subset of RUNX1-bookmarked genes in the initiation of the EMT at the onset of breast cancer development. This study will follow the following outline: cells will be synchronized in mitosis followed by elimination of RUNX1 through an auxin-induced degron (AID) system. Cells will then be released for transcriptome analysis by global run-on (GRO) sequencing (which will allow for specific sequencing only of nascent RNA transcribed post RUNX1 degradation), western blot, and qPCR, as well as phenotypic analysis of morphological changes through immunofluorescence microscopy. Overlap of significantly altered genes with genes previously identified as bookmarked by RUNX1 will provide us with a clearer understanding of the mechanism by which RUNX1 regulates essential genes to maintain cellular stability and phenotype, which when left unregulated contribute to breast cancer development.
Primary Faculty Mentor Name
Sayyed Kaleem Zaidi
Secondary Mentor Name
Janet L. Stein
Graduate Student Mentors
Joshua Rose
Faculty/Staff Collaborators
Sayyed Kaleem Zaidi (Graduate Student Mentor)
Status
Undergraduate
Student College
College of Arts and Sciences
Second Student College
Graduate College
Program/Major
Biochemistry
Second Program/Major
Pharmacology
Primary Research Category
Biological Sciences
Secondary Research Category
Health Sciences
The Role of Mitotic Gene Bookmarking in the Epithelial-to-Mesenchymal Transition in Breast Cancer
The epithelial to mesenchymal transition (EMT), a cellular transformation through which epithelial cells lose their adhesive properties and epithelial phenotype for a migratory and often aggressive/invasive mesenchymal phenotype, plays an important role in the initiation of breast cancer. Previous studies by our group have shown that loss of the RUNX1 transcription factor leads to the initiation of the EMT in mammary breast epithelial cells. However, the precise epigenetic mechanism by which RUNX1 maintains the epithelial phenotype remains incompletely understood. We hypothesize that RUNX1 functions through mitotic gene bookmarking, an epigenetic mechanism in which RUNX1 occupies target genes throughout mitosis to regulate their expression immediately after mitosis and maintain normal cellular proliferation, differentiation, and phenotype. A recent study in our lab showed retention of RUNX1 on a subset of RNA Pol - I and II - transcribed protein coding genes and long non-coding RNA genes important in determination of epithelial phenotype. Inhibition of RUNX1 DNA binding resulted in distinct changes in cellular morphology, gene expression, and global protein synthesis. This study provides the conceptual framework for my project, i.e., to characterize the role(s) of a candidate subset of RUNX1-bookmarked genes in the initiation of the EMT at the onset of breast cancer development. This study will follow the following outline: cells will be synchronized in mitosis followed by elimination of RUNX1 through an auxin-induced degron (AID) system. Cells will then be released for transcriptome analysis by global run-on (GRO) sequencing (which will allow for specific sequencing only of nascent RNA transcribed post RUNX1 degradation), western blot, and qPCR, as well as phenotypic analysis of morphological changes through immunofluorescence microscopy. Overlap of significantly altered genes with genes previously identified as bookmarked by RUNX1 will provide us with a clearer understanding of the mechanism by which RUNX1 regulates essential genes to maintain cellular stability and phenotype, which when left unregulated contribute to breast cancer development.