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IL13Rα2 promotes the proliferative switch required for outgrowth of breast cancer brain metastases

ABSTRACT: The survival of women with brain metastases (BM) from breast cancer remains very poor, and more than 80% will die within a year of their diagnosis. Here we define the function of IL13Rα2 in outgrowth of breast cancer brain metastases (BCBM) in vitro and in vivo, and postulate IL13Rα2 as a suitable therapeutic target for BM. Experimental design: We performed IHC staining of IL13Rα2 in BCBM to define its prognostic value. Using inducible-shRNAs in TNBC and HER2+ breast-brain metastatic models we assessed IL13Rα2 function in vitro and in vivo. We performed RNAseq and functional studies to define the molecular mechanisms underlying IL13Rα2 function in BCBM. Results: High IL13Rα2 expression in BCBM predicted worse survival after BM diagnoses. IL13Rα2 was essential for cancer-cell survival, promoting proliferation while repressing invasion. IL13Rα2 KD resulted in repression of cell cycle and proliferation mediator Cyclin D2 and upregulation of Ephrin B1 signaling. Ephrin-B1 (i) promoted invasion of BC cells in vitro, (ii) marked micrometastasis and invasive fronts in BCBM, (iii) predicted shorter disease-free survival (DFS) and BM-free survival (BMFS) in breast primary tumors known to metastasize to the brain. In experimental metastases models, which bypass early tumor invasion, downregulation of IL13Rα2 prior or after tumor seeding and brain intravasation decreased BMs, suggesting that IL13Rα2 and a switch to a more proliferative phenotype is critical to BM outgrowth.

ORGANISM(S): Homo sapiens

PROVIDER: GSE165898 | GEO | 2021/06/30

REPOSITORIES: GEO

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IL13Rα2 promotes the proliferative switch required for outgrowth of breast cancer brain metastases

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