Elucidating the role of the gap 0 switch 2 gene in breast cancer

Breast cancer has the second highest cancer mortality rate in women in the United States. While current treatments have significantly improved patient outlook, breast cancer patients continue to face the risk of developing treatment resistance and experiencing relapse. Additionally, triple-negative breast cancer remains a lethal disease with few efficient therapeutic targets compared to receptor-positive breast cancer. This thesis summarizes the investigation of the gap 0 switch 2 gene and its impact on estrogen-receptor positive breast cancer and triple-negative breast cancer. G0/G1 switch gene 2 (G0S2) is known to inhibit lipolysis by inhibiting adipose triglyceride lipase (ATGL). In this report, we dissect the role of G0S2 in ER+ versus ERbreast cancer. Overexpression of G0S2 in ER- cells increased cell proliferation, while G0S2 overexpression in ER+ cells decreased cell proliferation. Transcriptome analysis revealed that G0S2 mediated distinct but overlapping transcriptional responses in ERand ER+ cells. G0S2 reduced expression of genes associated with an epithelial phenotype, especially in ER- cells, including CDH1, ELF3, STEAP4 and TACSTD2, suggesting promotion of the epithelial-mesenchymal transition (EMT). G0S2 also repressed the expression of genes involved in estrogen signaling and estrogen receptor target gene signatures, especially in ER+ cells, including TFF1 and TFF3. In addition, G0S2 overexpression increased cell migration in ER- cells and increased estrogen deprivation sensitivity in ER+ cells. Interestingly, two genes downstream of ATGL in fat utilization and very important in steroid hormone biosynthesis, HMGCS1 and HMGCS2, were downregulated in G0S2 overexpressing ER+ cells. In addition, HSD17B11, a gene that converts estradiol to its less estrogenic derivative, estrone, was highly upregulated in iii G0S2 overexpressing ER+ cells, suggesting G0S2 overexpression has a negative effect on estradiol production and maintenance. High expression of G0S2 and HSD17B11 was associated with improved relapse-free survival in breast cancer patients while high expression of HMGSC1 was associated with poor survival. Finally, we deleted G0S2 in breast cancer-prone MMTV-PyMT mice. Our data indicates a complex role for G0S2 in breast cancer, dependent on ER status, that may be partially mediated by suppression of the estrogen signaling pathway.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

VMS - Comparative Biosciences

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2023

Author dc:creator

• Corbet, Andrea K

Contributors dc:contributor

• Spinella, Michael
• Bagchi, Indrani
• Nelson, Erik
• Bonthuis, Paul

• Breast Cancer
• Antiestrogen
• Epithelial Mesenchymal Transition
• Estrogen Receptor
• G0s2

Statement dc:rights

• Copyright 2023 Andrea Corbet

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/121479

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F121479