CRISPR-Cas9 directed modelling of estrogen receptor mutations identified in breast cancer

ABSTRACT: 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.

ORGANISM(S): Homo sapiens

PROVIDER: GSE147745 | GEO | 2022/08/09

REPOSITORIES: GEO