Investigating the transcriptional regulation of BCL11A in Triple-negative Breast Cancer

Breast cancer is the most common type of cancer in women worldwide. It can be classified into several subtypes based on the histological expression of Estrogen, Progesterone and HER-2 receptors. The most aggressive subtype of breast cancer is called Triple-negative breast cancer (TNBC) and is clinically defined by the absence of the three receptors mentioned above. These TNBC patients have the poorest prognostic outcome among the subtypes and highest mortality rate due to the lack of targeted treatments. A recent study has shown the expression of the transcription regulator BCL11A, to be upregulated specifically in TNBC compared to the other subtypes of breast cancer. In addition, BCL11A has also been experimentally demonstrated to be an oncogene in these aggressive tumours, thus making it an interesting target for new drug developments. However, little is known about how BCL11A is regulated at the transcriptional level in breast cancer. To tackle this problem, this project implements a novel proteomic approach utilising the Clustered regularly interspaced short palindromic repeats – CRISPR associated 9 (CRISPR-Cas9) technology, to identify putative transcriptional regulators of BCL11A in TNBC. The first step of this project involves the identification of regulatory sites on BCL11A that display high transcriptional regulations. This was achieved using the CRISPR-Cas9 knock-out approach. We then employed the mutated catalytically inactive Cas9 (dCas9) to target these sites and to pull down proteins in close proximity. This novel approach led to the identification of DEK, SSRP1 and PSIP1 as potential regulators of BCL11A’s expression. Experimentally, I found knocking- down DEK, SSRP1 and PSIP1 resulted in a reduction in BCL11A’s expression in TNBC. These results highlight a novel approach for the identification of transcription regulators of BCL11A’s in TNBC and potential targets for therapeutic interventions for these patients.

Name dc:type.qualificationname

Doctor of Philosophy (PhD)

Level dc:type.qualificationlevel

Doctoral

Grantor dc:publisher.institution

University of Cambridge

Year dc:date.issued

2019

Author dc:creator

• Tsang, Nicola Hoi Yee

Advisor dc:contributor.advisor

• Khaled, Walid

• Breast Cancer
• Triple-negative Breast Cancer
• BCL11A
• Transcription
• CRISPR-Cas9
• RIME
• DEK
• SSRP1
• PSIP1

Licence

• https://www.repository.cam.ac.uk/bitstreams/c6a8d60c-3e76-4c5c-bb86-7526144d32e7/download
• https://www.rioxx.net/licenses/all-rights-reserved/

Language dc:language

en

DOI dc:identifier.doi

https://doi.org/10.17863/CAM.44739

OAI identifier oai:identifier

oai:www.repository.cam.ac.uk:1810/297685