The impact of CRISPR/Cas9 generated mutations in pioneer transcription factors FOXA1 and GATA3 on oestrogen receptor function
(2018) MOBN03 20172Degree Projects in Molecular Biology
- Abstract
- Breast cancer is the most common cancer among women and two thirds of all breast cancers are classified as oestrogen receptor positive.
ER is a transcription factor that regulates gene expression and promote cell proliferation that is critical in mammary gland development, and its aberrant activity is commonly present in breast cancer.
As a nuclear receptor, ER activity could be diverted by either its aberrant DNA-binding that enables a direct regulation of gene expression and/or its aberrant response to an activating ligand, oestrogen. The ability of ER transcription factors to bind DNA and activate gene transcription is deregulated in most breast cancers in the absence of mutations in this transcription factor, where ER is no longer... (More) - Breast cancer is the most common cancer among women and two thirds of all breast cancers are classified as oestrogen receptor positive.
ER is a transcription factor that regulates gene expression and promote cell proliferation that is critical in mammary gland development, and its aberrant activity is commonly present in breast cancer.
As a nuclear receptor, ER activity could be diverted by either its aberrant DNA-binding that enables a direct regulation of gene expression and/or its aberrant response to an activating ligand, oestrogen. The ability of ER transcription factors to bind DNA and activate gene transcription is deregulated in most breast cancers in the absence of mutations in this transcription factor, where ER is no longer under usual control mechanisms.
Because ERs drive most breast cancers in the absence of mutations in its coding region, we hypothesise that the ER function may be diverted in breast cancer through epigenetic mechanisms, thus aberrant ER activities becomes a key driving force in inducing uncontrolled cell proliferation that lead to development and progression of oestrogen-induced breast cancers. We also propose that lowering the expression of transcription factors FOXA1 and GATA3 may deregulate ER function through epigenetic mechanisms and revert methylation patterns. in ER binding sites, from hypo- to hypermethylated. (Less) - Popular Abstract
- The hidden mechanisms of breast cancer
Breast cancer is the most common cancer type in women in the world today. While good treatments for majority of breast cancers exist, the resistance to these drugs is not uncommonly acquired during the treatment. Oestrogen receptor is a protein which is very important for balance inside the cells and is deregulated in overwhelming majority of breast cancers. Two proteins called FOXA1 and GATA3 has been recently proven to be often coupled with oestrogen receptor which makes them potential key elements in unlocking the underlying mechanisms in breast cancer.
Incidence of breast cancer is three times higher in Northern American and Western Europe than it is in Eastern Asia and Central Africa. Also,... (More) - The hidden mechanisms of breast cancer
Breast cancer is the most common cancer type in women in the world today. While good treatments for majority of breast cancers exist, the resistance to these drugs is not uncommonly acquired during the treatment. Oestrogen receptor is a protein which is very important for balance inside the cells and is deregulated in overwhelming majority of breast cancers. Two proteins called FOXA1 and GATA3 has been recently proven to be often coupled with oestrogen receptor which makes them potential key elements in unlocking the underlying mechanisms in breast cancer.
Incidence of breast cancer is three times higher in Northern American and Western Europe than it is in Eastern Asia and Central Africa. Also, the incidence grows with the level of how developed the region is. This indicates a clear connection to environmental causes which can be connected to the modern lifestyle. One of the first changes that happens inside the cells as a response to environmental factors are alterations of epigenetic patterns. Epigenetics is a discipline in molecular biology focused on DNA changes which do not involve change of the actual DNA sequence but rather additional functional groups on the DNA strand and histones (proteins around which DNA molecules are wrapped).
The relationship between FOXA1 and GATA3 proteins and the methylation changes in breast cancer is not clear. It is just like the question about a chicken and an egg, not obvious which one came first. Is it that these proteins are upregulated due to demethylation or the opposite scenario where another cause upregulates FOXA1 and GATA3 which in turn cause demethylation by their actions?
CRISPR/Cas9 technology
To find out if there is a clear and reversible relationship between our target proteins and methylation the proteins will be knocked-out (disabled) in the cancer cells. Several strategies and tools to achieve this exit. However, knocking-out a gene is never an easy task. Few years ago, a revolutionary technology has become popular for genome editing; CRISPR/Cas9 system. The name stands for Clustered Regularly Interspaced Short Palindromic Repeats and CRISPR associated protein 9. This system should be easy to use and extremely specific and efficient. Throughout the course of my project I found even though it is supposed to be an easy to use system I have spent months optimising it.
Populations of cancer cells with partially knocked-out FOXA1 and GATA3 have been collected and will be analysed using the newest methylation sequencing technology to estimate what methylation changes are connected to removal of FOXA1 and GATA3. This is possible as the cells which do not lack these two proteins will have the same methylation patterns and the control so the only observed differences in methylation (if any) will be due to removal of FOXA1 and GATA3.
Master’s Degree Project in Molecular Biology 60 credits 2018
Department of Biology, Lund University
Advisor: Zdenko Herceg
Epigenetics Group, International Agency for Research on Cancer (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/8963475
- author
- Bobrik, Miroslav
- supervisor
- organization
- course
- MOBN03 20172
- year
- 2018
- type
- H2 - Master's Degree (Two Years)
- subject
- language
- English
- id
- 8963475
- date added to LUP
- 2018-11-26 16:24:08
- date last changed
- 2018-11-26 16:24:08
@misc{8963475,
abstract = {{Breast cancer is the most common cancer among women and two thirds of all breast cancers are classified as oestrogen receptor positive.
ER is a transcription factor that regulates gene expression and promote cell proliferation that is critical in mammary gland development, and its aberrant activity is commonly present in breast cancer.
As a nuclear receptor, ER activity could be diverted by either its aberrant DNA-binding that enables a direct regulation of gene expression and/or its aberrant response to an activating ligand, oestrogen. The ability of ER transcription factors to bind DNA and activate gene transcription is deregulated in most breast cancers in the absence of mutations in this transcription factor, where ER is no longer under usual control mechanisms.
Because ERs drive most breast cancers in the absence of mutations in its coding region, we hypothesise that the ER function may be diverted in breast cancer through epigenetic mechanisms, thus aberrant ER activities becomes a key driving force in inducing uncontrolled cell proliferation that lead to development and progression of oestrogen-induced breast cancers. We also propose that lowering the expression of transcription factors FOXA1 and GATA3 may deregulate ER function through epigenetic mechanisms and revert methylation patterns. in ER binding sites, from hypo- to hypermethylated.}},
author = {{Bobrik, Miroslav}},
language = {{eng}},
note = {{Student Paper}},
title = {{The impact of CRISPR/Cas9 generated mutations in pioneer transcription factors FOXA1 and GATA3 on oestrogen receptor function}},
year = {{2018}},
}