CRISPR-Cas9 directed modelling of estrogen receptor mutations identified in breast cancer
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PROVIDER: PRJNA616301 | ENA |
REPOSITORIES: ENA
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Project description:Estrogen receptor (ER) is the major driver of a large proportion of breast cancers, and many therapies have been designed to target it. These include anti-estrogens, which target ER directly, and aromatase inhibitors, which instead prevent the biosynthesis of estrogen in post-menopausal women. These therapies have been largely successful, but unfortunately many patients eventually succumb to resistance. A hotspot of mutations in exon 8 of ESR1, which cause the ER to be constitutively active, have been discovered in advanced breast cancer patients, and are one cause of resistance to aromatase inhibitors as well as a reduced response to anti-estrogen therapies. Since most studies in to these mutations have so far focused on the mostly commonly seen mutations, Y537S and D538G, it is important to extend our understanding to other frequently found mutations to determine whether there are intrinsic differences between them. For this purpose, CRISPR-Cas9 was used in order to model the following mutations found in exon 8 of ESR1 in breast cancer patients, L536R, Y537C, Y537S, Y537N and D538G, in MCF7 cells, with between two to four clones of each mutation generated. Growth in the absence of estrogen and in the presence of various SERDs was tested to investigate differences in sensitivity between mutations. RNA-seq was carried out in the ESR1 mutant MCF7 lines under full medium conditions to look for gene expression changes compared to WT, shared between all mutations, or the possibility of differences between specific mutations, which were not due to the fact that the ESR1 mutant lines can grow in the absence of estrogen. The results of which should provide great insight into potential alternative genes or pathways, which could be targeted in patients harbouring these mutations.
2022-08-09 | GSE147745 | GEO
Project description:Frequent and extensive Cas9-directed genomic damage
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Project description:Chromatin-directed proteomics-identified network of endogenous androgen receptor in prostate cancer cells
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Project description:The clustered regularly interspaced short palindromic repeat (CRISPR)-associated enzyme Cas9 is an RNA-guided nuclease that has been widely adapted for genome editing in eukaryotic cells. However, the in vivo target specificity of Cas9 is poorly understood and most studies rely on in silico predictions to define the potential off-target editing spectrum. Using chromatin immunoprecipitation followed by sequencing (ChIP-seq), we delineate the genome-wide binding panorama of catalytically inactive Cas9 directed by two different single guide (sg) RNAs targeting the Trp53 locus. Cas9:sgRNA complexes are able to load onto multiple sites with short seed regions adjacent to 5’NGG3’ protospacer adjacent motifs (PAM). Examination of dmCas9 binding sites using two Trp53 targeting sgRNAs in Arf -/- MEF cell line (mouse).
2014-08-29 | E-GEOD-57650 | biostudies-arrayexpress
Project description:Based on the hypothesis that, enhancing the local concentration of donor oligos could increase the correction rates, we generated and tested novel CRISPR-Cas9 systems, in which the DNA repair template is covalently conjugated to Cas9 (RNPD system). To validate our results from the HEK293T reporter cells, we here tested our approach at different endogenous genomic loci and in different cell types. We first targeted the human beta globin (HBB) locus in the K562 cell line, and analyzed correction- and editing frequencies using next generation sequencing (NGS). Next we targeted the Rosa26 and proprotein convertase subtilisin/kexin type 9 (Pcsk9) locus in mouse embryonic stem cells (mESCs). Here, RNPD system was always compared to Cas9 SNAP-tag fusion proteins with uncoupled donor oligos. To also directly compare the engineered RNPD system to the classical CRISPR-Cas9 system, we performed experiments where we used wild-type Cas9 with the uncoupled donor oligos as a control. We therefore targeted the fluorescent reporter locus as well as the endogenous loci HBB, empty spiracles homeobox 1 (EMX1), and C-X-C chemokine receptor type 4 (CXCR4) in HEK293T cells. Finally, we performed the analysis of three computationally predicted off-target sites of the reporter locus.
2018-06-04 | E-MTAB-6808 | biostudies-arrayexpress
Project description:Gene disruption by CRISPR/Cas9 is highly efficient and relies on the error-prone non-homologous end-joining (NHEJ) pathway. Conversely, precise gene editing requires homology-directed repair (HDR), which occurs at a lower frequency than NHEJ in mammalian cells. Here, by testing whether manipulation of DNA repair factors would improve HDR efficacy, we show that transient ectopic co-expression of RAD52 and a dominant-negative 53BP1 (dn53BP1) synergize to enable efficient HDR using a single-stranded oligonucleotide DNA donor template at multiple loci in human cells, including patient-derived induced pluripotent stem (iPS) cells. Co-expression of RAD52 and dn53BP1 improves multiplexed HDR-mediated editing, whereas expression of RAD52 alone enhances HDR with Cas9 nickase. Our data show that the frequency of NHEJ-mediated DSB repair in the presence of these two factors is not suppressed, and suggest that dn53BP1 competitively antagonizes 53BP1 to augment HDR in combination with RAD52. Importantly, co-expression of RAD52 and dn53BP1 does not alter Cas9 off-target activity. These findings support the use of RAD52 and dn53BP1 co-expression to overcome bottlenecks that limit HDR in precision genome editing.
2017-11-23 | GSE103241 | GEO
Project description:Estrogen receptor alpha (ESR1) mutations have been identified in hormone therapy resistant breast cancer and primary endometrial cancer. Analyses in breast cancer suggests that mutant ESR1 exhibits estrogen independent activity. In endometrial cancer, ESR1 mutations are associated with worse outcomes and less obesity, however experimental investigation of these mutations has not been performed. Using a unique CRISPR/Cas9 strategy, we introduced the D538G mutation, a common endometrial cancer mutation that alters the ligand binding domain of ESR1, while epitope tagging the endogenous locus. We discovered estrogen-independent mutant ESR1 genomic binding that is significantly altered from wildtype ESR1. The D538G mutation impacted expression, including a large set of non-estrogen regulated genes, and chromatin accessibility, with most affected loci bound by mutant ESR1. Mutant ESR1 is unique from constitutive ESR1 activity as mutant-specific changes are not recapitulated with prolonged estrogen exposure. Overall, D538G mutant ESR1 confers estrogen-independent activity while causing additional regulatory changes in endometrial cancer cells that are distinct from breast cancer cells.
2019-06-11 | GSE132428 | GEO
Project description:Estrogen receptor alpha (ESR1) mutations have been identified in hormone therapy resistant breast cancer and primary endometrial cancer. Analyses in breast cancer suggests that mutant ESR1 exhibits estrogen independent activity. In endometrial cancer, ESR1 mutations are associated with worse outcomes and less obesity, however experimental investigation of these mutations has not been performed. Using a unique CRISPR/Cas9 strategy, we introduced the D538G mutation, a common endometrial cancer mutation that alters the ligand binding domain of ESR1, while epitope tagging the endogenous locus. We discovered estrogen-independent mutant ESR1 genomic binding that is significantly altered from wildtype ESR1. The D538G mutation impacted expression, including a large set of non-estrogen regulated genes, and chromatin accessibility, with most affected loci bound by mutant ESR1. Mutant ESR1 is unique from constitutive ESR1 activity as mutant-specific changes are not recapitulated with prolonged estrogen exposure. Overall, D538G mutant ESR1 confers estrogen-independent activity while causing additional regulatory changes in endometrial cancer cells that are distinct from breast cancer cells.
2019-06-11 | GSE132426 | GEO
Project description:Estrogen receptor alpha (ESR1) mutations have been identified in hormone therapy resistant breast cancer and primary endometrial cancer. Analyses in breast cancer suggests that mutant ESR1 exhibits estrogen independent activity. In endometrial cancer, ESR1 mutations are associated with worse outcomes and less obesity, however experimental investigation of these mutations has not been performed. Using a unique CRISPR/Cas9 strategy, we introduced the D538G mutation, a common endometrial cancer mutation that alters the ligand binding domain of ESR1, while epitope tagging the endogenous locus. We discovered estrogen-independent mutant ESR1 genomic binding that is significantly altered from wildtype ESR1. The D538G mutation impacted expression, including a large set of non-estrogen regulated genes, and chromatin accessibility, with most affected loci bound by mutant ESR1. Mutant ESR1 is unique from constitutive ESR1 activity as mutant-specific changes are not recapitulated with prolonged estrogen exposure. Overall, D538G mutant ESR1 confers estrogen-independent activity while causing additional regulatory changes in endometrial cancer cells that are distinct from breast cancer cells.
2019-06-11 | GSE132424 | GEO
Project description:Assessing and enhancing migration of human myogenic progenitors using directed iPS cell differentiation and advanced tissue modelling
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