NR2F2 is a key downstream effector of NF1 loss in estorgen receptor positive breast cancer (RNA-seq)
NF1 loss-of-function mutations are enriched in hormone receptor positive (HR+) metastatic breast cancer (MBC) and mediate endocrine therapy resistance. To identify therapeutic vulnerabilities in this context, we performed CRISPR/Cas9 screens in wildtype and NF1 knockout isogenic HR+ models and identified NR2F2, an orphan nuclear receptor, to be essential specifically in NF1 loss cells. The NR2F2 dependence was induced as a consequence of NR2F2 upregulation via the activation of the MAPK pathway in these cells. Enforced overexpression of NR2F2 was sufficient to confer endocrine therapy resistance in the absence of NF1 loss, while of NR2F2 knockout or knockdown could enhance the efficacy of endocrine therapies in NF1 WT and NF1 loss models. Mechanistically, our comprehensive multi-omics approaches revealed that NR2F2 modulates chromatin accessibility and regulates ER-dependent transcription through its interaction with ER, transcriptional coregulators and chromatin remodelers at chromatin. Specifically, increased NR2F2 in NF1 loss cells dramatically enhanced the association with transcriptional corepressors, which resulted in attenuation of chromatin accessibility and ER occupancy, and impaired ER transcriptional program. Our findings identify the nuclear receptor NR2F2 as a downstream effector of NF1 loss, and it is essential and potentially druggable mediator of endocrine therapy resistance. We performed gene expression profiling analysis using data obtained from RNA-seq of MCF7 sgNT, sgNF1, sgNR2F2 and double knockout (DKO) cells under different conditions. Overall design: Comparative gene expression profiling analysis of RNA-seq data for MCF7 sgNT, sgNF1, sgNR2F2 and double knockout (DKO) cells under different conditions.