title: Hierarchical paracrine interaction of breast cancer associated fibroblasts with cancer cells via hMAPK-microRNAs to drive ER-negative breast cancer phenotype.
abstract: Multiple juxtacrine and paracrine interactions occur between cancer cells and non-cancer cells of the tumor microenvironment (TME) that direct tumor progression. Cancer Associated Fibroblasts (CAFs) are an integral component of the TME, and the majority of breast tumor stroma is comprised of CAFs. Heterotypic interactions between cancer cells and non-cancer cells of the TME occur via soluble agents, including cytokines, hormones, growth factors, and secreted microRNAs. We previously identified a microRNA signature indicative of hyperactive MAPK signaling (hMAPK-miRNA signature) that significantly associated with reduced recurrence-free and overall survival. Here we report that the hMAPK-miRNA signature associates with a high metric of stromal cell infiltrate, and we investigate the role of microRNAs, particularly hMAPK-microRNAs, secreted by CAFs on estrogen receptor (ER) expression in breast cancer cells. ER-positive MCF-7/ltE2- cells were treated with conditioned media (CM) from CAFs derived from breast cancers of different PAM50 subtypes (CAFBAS, CAFHER2, and CAFLA). CAF CM isolated specifically from ER-negative primary breast tumors led to ER repression in vitro. Nanoparticle tracking analysis and transmission electron microscopy confirmed the presence of CAF-secreted exosomes in CM and the uptake of these exosomes by the ER+ MCF-7/ltE2- cells. Differentially expressed microRNAs in CAF CM as well as in MCF-7/ltE2- cells treated with this CM were identified. Knockdown of miR-221/222 in CAFBAS resulted in knockdown of miR221/222 levels in the conditioned media and the CM from CAFBAS; miR221/222 knockdown rescued ER repression in ER-positive cell lines treated with CAFBAS-CM. Collectively, our results demonstrate that CAF-secreted microRNAs are directly involved in ER-repression, and may contribute to the MAPK-induced ER repression in breast cancer cells.
authors.affiliation: a Cancer Biology; University of Miami ; Miami , FL USA.
authors.forename: Sanket H
authors.initials: SH
authors.lastname: Shah
authors.affiliation: c Sylvester Comprehensive Cancer Center; University of Miami Miller School of Medicine ; Miami , FL USA.
authors.forename: Philip
authors.initials: P
authors.lastname: Miller
authors.affiliation: d Diabetes Research Institute; University of Miami Miller School of Medicine ; Miami , FL USA.
authors.forename: Marta
authors.initials: M
authors.lastname: Garcia-Contreras
authors.affiliation: a Cancer Biology; University of Miami ; Miami , FL USA.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Ao
authors.affiliation: c Sylvester Comprehensive Cancer Center; University of Miami Miller School of Medicine ; Miami , FL USA.
authors.forename: Leah
authors.initials: L
authors.lastname: Machlin
authors.affiliation: e Department of Biology ; University of Miami ; Miami , FL USA.
authors.forename: Emilio
authors.initials: E
authors.lastname: Issa
authors.affiliation: b Department of Internal Medicine ; University of Miami Miller School of Medicine ; Miami , FL USA.|c Sylvester Comprehensive Cancer Center; University of Miami Miller School of Medicine ; Miami , FL USA.
authors.forename: Dorraya
authors.initials: D
authors.lastname: El-Ashry
mesh_terms: D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D017077:Culture Media, Conditioned; D055354:Exosomes / Q000502:physiology; D005260:Female; D005347:Fibroblasts / Q000201:enzymology*; D015870:Gene Expression; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D061986:MCF-7 Cells; D035683:MicroRNAs / Q000502:physiology*; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D019899:Paracrine Communication; D010641:Phenotype; D034622:RNA Interference; D011960:Receptors, Estrogen / Q000235:genetics / Q000378:metabolism*; D059016:Tumor Microenvironment
chemical_list: D017077:Culture Media, Conditioned; D035683:MicroRNAs; D020928:Mitogen-Activated Protein Kinases; D011960:Receptors, Estrogen; C525709:MIR221, human; C525710:MIR222, human
keywords: CAFs; Estrogen receptor; MAPK; TME; exosomes; microRNA